Optimisation Developments
Ltd. and West Herts College
The Link, Hemel
Hempstead
Environmental Statement - Volume 1
Project Ref: 25374
June 2013
Peter Brett Associates LLP
10 Queen Square
Bristol
BS1 4NT
T: 0117 9281560
F: 0117 9281570
E: bristol@peterbrett.com
The Link, Hemel Hempstead
Environmental Statement - Volume 1
We print on 100% recycled paper from sustainable suppliers accredited to ISO 14001.
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Environmental Statement - Volume 1
Document Control Sheet
Project Name: The Link, Hemel Hempstead
Project Ref:
25374
Report Title:
Environmental Statement - Volume 1
Date:
June 2013
Name
Position
Signature
Date
Prepared by:
Various
Various
NA
Various
Reviewed by:
Cicely Postan
Principal
CP
20/06/13
Approved by:
Chris Quinsee
Partner
CQ
24/06/13
For and on behalf of Peter Brett Associates LLP
Revision
Date
Description
Prepared
Reviewed
Approved
00
19/04/13
Draft for DBC review
Var
CP
QQ
01
20/06/13
Draft for review
Var
CP
CQ
Peter Brett Associates LLP disclaims any responsibility to the Client and others in respect of any
matters outside the scope of this report. This report has been prepared with reasonable skill, care and
diligence within the terms of the Contract with the Client and generally in accordance with the
appropriate ACE Agreement and taking account of the manpower, resources, investigations and
testing devoted to it by agreement with the Client. This report is confidential to the Client and Peter
Brett Associates LLP accepts no responsibility of whatsoever nature to third parties to whom this
report or any part thereof is made known. Any such party relies upon the report at their own risk.
© Peter Brett Associates LLP 2013
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Contents
1
Introduction ............................................................................................................................... 1
The Proposed Development .......................................................................................... 1
The Site .......................................................................................................................... 2
Terms and Definitions .................................................................................................... 3
The EIA, ES and Related Documents ........................................................................... 3
Consultation ................................................................................................................... 4
Project Team.................................................................................................................. 5
Structure of the Environmental Statement ..................................................................... 5
2
Site and Surrounding Area ...................................................................................................... 7
The Site .......................................................................................................................... 7
The surroundings ........................................................................................................... 8
History of the Site......................................................................................................... 10
Environmental Setting .................................................................................................. 11
3
The Proposed Development .................................................................................................. 12
Description of Proposed Development ........................................................................ 12
Utilities ......................................................................................................................... 17
Incorporated Mitigation ................................................................................................ 19
Consideration of Alternatives ....................................................................................... 20
4
Construction and Site Management ..................................................................................... 27
Introduction .................................................................................................................. 27
Construction Works & Programme .............................................................................. 27
Construction Management ........................................................................................... 28
Construction Traffic ...................................................................................................... 30
Construction Waste...................................................................................................... 31
5
Assessment Method ............................................................................................................... 32
Introduction .................................................................................................................. 32
EIA Regulations ........................................................................................................... 32
The EIA Process .......................................................................................................... 32
Screening and Scoping ................................................................................................ 33
Consultations ............................................................................................................... 34
Committed Developments ........................................................................................... 34
Assessment Assumptions ............................................................................................ 35
Assessing Effects......................................................................................................... 35
Uncertainty ................................................................................................................... 37
Mitigation of Adverse Effects ....................................................................................... 37
Residual Effects ........................................................................................................... 37
Significance Criteria ..................................................................................................... 37
Cumulative Effects ....................................................................................................... 38
Impact Interactions....................................................................................................... 39
Water Framework Directive Assessment..................................................................... 39
6
Planning and Policy Context ................................................................................................. 40
Introduction .................................................................................................................. 40
National Policy ............................................................................................................. 40
Local Policy .................................................................................................................. 43
Supplementary Planning Documents and Guidance ................................................... 48
Summary...................................................................................................................... 50
7
Hydrology and Drainage ........................................................................................................ 51
Introduction .................................................................................................................. 51
Policy Context .............................................................................................................. 51
Methodology ................................................................................................................ 56
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Baseline Conditions ..................................................................................................... 61
Potential Environmental Effects ................................................................................... 75
Mitigation and Enhancement Measures ...................................................................... 77
Residual Effects ........................................................................................................... 82
Summary...................................................................................................................... 83
References ................................................................................................................... 84
8
Ecology & Nature Conservation ............................................................................................ 86
Introduction .................................................................................................................. 86
Policy Context .............................................................................................................. 86
Methodology ................................................................................................................ 90
Baseline Conditions ..................................................................................................... 98
Potential effects ......................................................................................................... 106
Environmental measures and mitigation ................................................................... 108
Residual effects ......................................................................................................... 111
Summary.................................................................................................................... 118
References ................................................................................................................. 120
9
Ground Conditions ............................................................................................................... 121
Introduction ................................................................................................................ 121
Policy Context ............................................................................................................ 121
Methodology .............................................................................................................. 123
Baseline Conditions ................................................................................................... 126
Potential Effects ......................................................................................................... 131
Mitigation Measures ................................................................................................... 134
Residual Effects ......................................................................................................... 137
Summary.................................................................................................................... 139
References ................................................................................................................. 140
10
Socio-Economics .................................................................................................................. 143
Introduction ................................................................................................................ 143
Policy Context ............................................................................................................ 143
Methodology .............................................................................................................. 147
Baseline Conditions ................................................................................................... 150
Assessment of Effects ............................................................................................... 159
Mitigation .................................................................................................................... 168
Summary.................................................................................................................... 170
References ................................................................................................................. 171
11
Townscape and Visual ......................................................................................................... 172
Introduction ................................................................................................................ 172
Policy Context ............................................................................................................ 172
Methodology .............................................................................................................. 179
Baseline Conditions ................................................................................................... 199
Potential Effects ......................................................................................................... 223
Mitigation and Enhancement Measures .................................................................... 246
Residual Effects ......................................................................................................... 248
Summary.................................................................................................................... 256
References ................................................................................................................. 258
12
Transport and Access .......................................................................................................... 260
Introduction ................................................................................................................ 260
Policy Context ............................................................................................................ 260
Methodology .............................................................................................................. 267
Baseline Conditions ................................................................................................... 272
Potential Effects ......................................................................................................... 280
Mitigation Measures ................................................................................................... 287
Residual Effects ......................................................................................................... 288
Summary.................................................................................................................... 288
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13
Noise & Vibration .................................................................................................................. 290
Introduction ................................................................................................................ 290
Policy Context ............................................................................................................ 290
Methodology .............................................................................................................. 294
Baseline Conditions ................................................................................................... 301
Potential Effects ......................................................................................................... 301
Mitigation Measures ................................................................................................... 305
Residual Effects ......................................................................................................... 306
Summary.................................................................................................................... 307
References ................................................................................................................. 307
14
Air Quality .............................................................................................................................. 309
Introduction ................................................................................................................ 309
Policy Context ............................................................................................................ 309
Methodology .............................................................................................................. 312
Baseline Conditions ................................................................................................... 319
Potential Effects ......................................................................................................... 321
Mitigation & Enhancement ......................................................................................... 325
Residual Effects ......................................................................................................... 327
Summary.................................................................................................................... 327
References ................................................................................................................. 328
15
Archaeology .......................................................................................................................... 330
Introduction ................................................................................................................ 330
Policy Context ............................................................................................................ 330
Methodology .............................................................................................................. 332
Baseline Conditions ................................................................................................... 334
Potential Effects ......................................................................................................... 338
Mitigation Measures ................................................................................................... 339
Residual Effects ......................................................................................................... 339
Summary.................................................................................................................... 340
15.8
References ................................................................................................................. 340
16
Built Heritage ........................................................................................................................ 342
Introduction ................................................................................................................ 342
Policy Context ............................................................................................................ 342
Methodology .............................................................................................................. 345
Baseline Conditions ................................................................................................... 350
Potential Effects ......................................................................................................... 354
Mitigation Measures ................................................................................................... 362
Residual Effects ......................................................................................................... 367
Summary.................................................................................................................... 374
References ................................................................................................................. 375
17
Summary & Impact Interactions .......................................................................................... 376
Introduction ................................................................................................................ 376
Methodology .............................................................................................................. 376
Construction Effects ................................................................................................... 377
Operation Effects ....................................................................................................... 378
18
Glossary ................................................................................................................................ 380
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1
Introduction
The Proposed Development
1.1.1
This Environmental Statement (ES) has been prepared in respect of a planning application
by Optimisation Development Ltd. and West Herts College, for the redevelopment of land to
the north of Hemel Hempstead town centre, to be known as The Link, Hemel. Figure 1,
Appendix A.1 shows the location of this development.
1.1.2
The planning application is a hybrid application. A hybrid application is one where part of the
application is a full application with no matters reserved, while part is in outline and for which
subsequent reserved matters application(s) will be required. The majority of the site is
covered by the full application and is for a foodstore, a college building, associated car
parking and landscaping. The full application as includes the diversion of a section of the
River Gade where it runs through the site.
1.1.3
The outline part of the development is for additional college buildings and associated car
parking. The outline development is proposed on the north western part of the site, on the
opposite bank of the River Gade from the college buildings for which full permission is being
sought.
1.1.4
Figure 2, Appendix A.1 shows site red line boundaries and green outline site boundary.
1.1.5
This ES documents collectively the likely significant environmental effects of both the
detailed and the outline elements of the hybrid planning applications. This is to allow a
robust approach to the environmental assessment of the full effects of proposed
development at The Link, Hemel Hempstead on the environment.
1.1.6
Currently the site is covered by several different uses. The northern part of the site contains
the low density buildings of West Herts College and the more southerly part of the site is
occupied by buildings of Dacorum Civic Centre, which include Dacorum Borough Council
(DBC) offices. Marlowes Methodists Church is located on the site, fronting onto Marlows
south of the current West Herts College buildings. The River Gade flows through the western
part of the site in a southerly direction.
1.1.7
The site is centrally located in Hemel Hempstead, located just to the north of the town centre
between the Old Town and new town. The proposals seek to make more efficient use of this
central site to provide a new foodstore and improved college facilities, which will link old and
new towns. The proposals have been drawn up in accordance with the adopted Hemel
Hempstead Town Centre Masterplan Supplementary Planning Document (January 2013);
see Chapter 6.
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The Site
1.2.1
The site is a developed area in central Hemel Hempstead. The northern part contains the
‘pavilion’ style campus of West Herts College. These are predominantly low rise buildings
located in managed grassland containing groups of mature trees, although buildings
bordering on Marlowes are up to three storeys.
1.2.2
Further south the site contains the building of Dacorum Civic Centre, including the DBC
offices. These buildings are taller than the college of about three to four storeys and the
Council building includes undercroft car parking. The outside space around these buildings
within the site is predominantly roads, pavements and concrete hardstanding.
1.2.3
Other features of the site include the River Gade that bisects the site, running in a southerly
direction. The River Gade through of the site contains only a nominal flow of the river, with
the much of the water flowing from the north entering a culvert off-site that passes under the
site. The site slopes down from the east to the River Gade. There are two water abstraction
boreholes on the site and an associated pump houses.
1.2.4
The site currently contains mature trees as part of the parkland setting of the college.
However, only two clusters of trees on site covered by Tree Preservation Orders (TPO).
1.2.5
The majority of the college and civil centre buildings within the site date back to the 1960s
and relate to the creation of the Hemel Hempstead new town. However, some buildings are
more recent such as an extension to the rear of the civic centre.
1.2.6
There is a Wesleyan Chapel, currently in use as Marlowes Methodists Church. The building
dates from late 19th Century and is of some local character.
1.2.7
The site directly borders Marlowes to the east, with the college campus open to the road.
This road is characterised by retail and commercial uses and links the old town to the new
town, with taller residential blocks of flats and a listed church opposite the southern end of
the site.
1.2.8
The boundary to the north is with Queensway and is marked by several mature/semi-mature
trees and a low wall. On the opposite side of the road is the listed building ‘The Bury’ in its
grounds and the Gadebridge Park public open space. This is within the Hemel Hempstead
Old Town Conservation Area that slightly overlaps the northern part of the site.
1.2.9
The west of the site opens directly onto Leighton Buzzard Road with wide grass verges. The
northern end of the road opposite the college is characterised by the garden fences of
houses that back onto it.
1.2.10
The southern edge of the site currently links with the other buildings of the civic centre,
including the police station, health centre and magistrates’ court. These buildings are similar
in style and age to the Dacorum Civic Centre buildings.
1.2.11
More detail on the site is given in Chapter 2 of the ES.
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Terms and Definitions
1.3.1
For ease of reference the following terms have been used in the ES:

The Link, Hemel Hempstead – the name of the development, for which planning
permission is being sought through the hybrid planning application;

The site – the area within the planning application boundary of the hybrid planning
application (see Appendix A.1 Figure 2);

Proposed development – the development for which planning permission is sought,
comprising the redeveloped college, foodstore, petrol station and associated
development. This also includes additional college buildings for which outline planning
permission is sought (see Appendix A.3).

River Gade realignment – this is the short stretch (275 m) of the River Gade that is to be
realigned to the west to accommodate development on the eastern bank.

Proposed outline development – this is the north western section of the site where
outline planning permission is being sought for new college buildings and associated car
parking (see Appendix A.1 Figure 2).
The EIA, ES and Related Documents
1.4.1
This Environmental Statement presents the findings of an Environmental Impact Assessment
(EIA) undertaken in accordance with The Town and Country Planning (Environmental Impact
Assessment) Regulations 2011, referred to as the ‘EIA Regulations’.
1.4.2
Running concurrently with the design process, the EIA has sought to identify appropriate
design and construction measures and good practice to mitigate potential adverse
environmental effects and maximise environmental opportunities which might arise as a
consequence of the construction and operation of the proposed development as well as
determining the residual environmental effects remaining after mitigation has been
incorporated.
1.4.3
The ES comprises the following separate volumes:
1.4.4
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
Volume 1: Main Report;

Volume 2: Appendices; and

Non-Technical Summary.
The other principal documents to be submitted as part of the planning application are:

Planning Statement;

Retail Statement;
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
Design & Access Statement and Conservation Area Appraisal (DAS);

Statement of Community Engagement;

Transport Assessment;

Flood Risk Assessment; and

Energy and Sustainability Statement.
Consultation
1.5.1
There has been on-going consultation with various statutory and non-statutory bodies to
inform the design and the EIA process. This topic-specification consultation is identified as
appropriate in each of the topic chapters of this ES.
1.5.2
A comprehensive programme of community consultation was undertaken during the
preparation of the proposed development scheme. The consultation was focused on a
public exhibition on Friday 26 April at West Herts College and Saturday 27 April at Marlowes
Shopping Centre, supported by a project website, consultation telephone line and email
address for those unable to attend. Invitations were sent to key local stakeholders and over
250 neighbouring properties, while a flyer was delivered to around 8,500 properties in the
wider area around the site. The exhibition was also well publicised in the local press.
1.5.3
Over 750 people attended the exhibition over the two days and the local response to the
proposals was very positive. The vast majority of visitors to the exhibition and those
providing written feedback welcomed all aspects of the plan. A total of 147 feedback forms
were completed, showing strong support for the proposed development, including 90% in
support of a new Morrisons foodstore and PFS and 93% in favour of the new West Herts
College campus.
1.5.4
A range of comments were made during the consultation process and included on the
feedback forms. The majority of comments were generally supportive of the proposals,
including the need for better food shopping choice, new jobs and improved education
facilities locally. A range of detailed issues and queries were also raised and these related
primarily to:
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
Transport and access – including traffic generation, parking, highway works, access on
foot / cycle / bus, deliveries;

Design and landscaping – including detailed design of the new buildings, layout of the
site, impact on existing trees, new landscaping proposals;

Amenity – including noise and visual impact on residential properties to the west of
Leighton Buzzard Road.
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1.5.5
These matters are addressed through the design of the proposed development , including
full assessment of transport impacts, improved permeability of the site for pedestrians and
assessments to asses noise and visual effects.
1.5.6
Full details can be found in the Statement of Community Engagement submitted with the
application
Project Team
1.6.1
The design of the proposed development has involved two principal project teams dealing
with the college and the foodstore elements of development. However, there has also been
a coordinated approach between the two to develop the whole site masterplan and
development proposals. Members of the team include:

DLA Architecture: Architects, Masterplanners and built heritage;

Amec: Ecology & Nature Conservation;

Archaeology Solutions: Archaeology;

Peter Brett Associates LLP: Planning Consultant; EIA Coordination, Socio-Economics,
Noise & Vibration, and Air Quality;

DLA Landscape: Townscape and Visual;

Weetwoods: Hydrology & Drainage;

Applied Geology: Ground Conditions;

CgMs: Built Heritage: and

SKM: Transport and traffic.
Structure of the Environmental Statement
1.7.1
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The ES is structured as follows:

Chapter 2: description of the site and the surrounding area;

Chapter 3: summarises the proposed development, including utilities and the
consideration of alternatives;

Chapter 4: outlines the construction works;

Chapter 5: provides the methodology adopted to undertake the EIA;

Chapter 6: summarises the planning and policy context to the proposed development;

Chapters 7 to 16: comprise the technical assessment chapters;
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
Chapter 17: assesses impact interactions and cumulative effects; and

Chapter 18: provides a glossary of terms.
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2
Site and Surrounding Area
The Site
2.1.1
The site is within central Hemel Hempstead. It is located on the route from the old town
centre to the new centre created when Hemel Hempstead new town was created. The site
is around 4.1 hectares and is all previously developed land, although it contains areas of
open space and a section of the River Gade. Figure 3, Appendix A.1 shows the setting of
the site and key features in the area, Figure 4, Appendix A.1 shows the current character of
the site as a set of photographs.
2.1.2
The site falls from Marlowes in the east down to the existing route of the River Gade, which
bisects the site. There is a distinct drop in levels between the eastern and western parts of
the site.
2.1.3
The northern part of the site contains the low rise (predominantly 1-2 storeys) and low
density buildings of the Dacorum Campus of West Herts College. These buildings are
designed as a series of ‘pavilions’ within a landscape of managed grassland, semi-mature
and mature trees and the River Gade runs through the site between the college buildings.
There are numerous footpaths across the college site, including those that cross the River
Gade.
2.1.4
The buildings of the college date from the 1960s and are characterised by building materials
of concrete and glass with flat roofs. Each building is separated from its neighbours by wide
areas of mown grass. The college campus is open to the street on the east and west sides,
with the pavement separated from the road by wide grass verges on the western side. The
northern boundary has low stone wall separating it from Queensway and the southern end
has footpath and road links to the civic centre.
2.1.5
A narrow strip at the northern end of the site is covered by the Hemel Hempstead Old Town
Conservation Area. However, this only includes a small part of a one building.
2.1.6
The southern part of the site contains the buildings DBC offices as part of Dacorum Civic
Centre. The building was designed as the new Town Hall for Hemel Hempstead in the
1960s, it is also characterised by a concrete and glass construction with a flat roof. The
building is around 3 storeys high from the Marlowes frontage, although this hides the
undercroft car park. There is a more modern extension to the west of the 1960s building of
red brick construction also with a flat roof. The extension is around 2 storeys from ground
level connected to the main building by a first floor walkway and backs directly onto the River
Gade, encroaching on the River corridor.
2.1.7
There is a plaza in front of the main DBC office building on Marlowes and in general the
setting of the building is hard landscaping and roads. However, there is a small amount of
open space to the west of the extension on the opposite side of the River Gade.
2.1.8
The site also contains the Marlowes Methodists Church. This is a brick built church with a
steeply pitched tiled roof. The church, built as a Wesleyan Chapel, dates from the late 19th
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century in a single period. The church comprises of a nave with integral north and south
aisles and west porch, chancel and short north and south transepts. The grounds extend
into the site, although there is no graveyard associated with the church.
2.1.9
Both the college and the civic centre have associated car parking. The principal college car
park is in the northwest corner of the site. Access to car parking is off Queensway near the
Leighton Buzzard Road roundabout.
2.1.10
Further parking on the site is provided between the civic centre and college. In these
locations there is an additional college car park, on road public car parking and the
undercroft public car parking to the Civic Centre. Access to these car parks is from Dacorum
Way, that links to Marlowes between the DBC offices, with an additional access on the site
adjacent to the Methodists church. Dacorum Way access roads wraps around the whole
civic centre including beyond the site to the magistrates’ court, with an exit onto Combe
Road and a separate spur exiting onto Marlowes outside the site.
2.1.11
Pedestrian access to the college site is not restrained on Marlowes, with no fences or walls
separating the site from the public pavement. On the west side the college is also directly
accessible from the public pavement. However, limited crossing places over the River Gade
constrain access to parts of the site. The principal pedestrian access to the civic centre DBC
offices is from Marlowes. Additional pedestrian access points are from Dacorum Way and
footpaths covering the whole of the area containing civic centre buildings. However,
pedestrian routes from the south of the civic centre to the DBC offices are limited by the
change in levels and a design that favours access by car. However, overall east west links
across the site at present are poor.
2.1.12
Other features of the site include the River Gade a ‘chalk stream’ or ‘chalk bourne’ that
bisects the site, running in a southerly direction. The part of the River Gade that flows
through the site is only part of the total flow of the River Gade as water is diverted into a
culvert just north of the site. This travels under the site only re-joining the river in Kings
Langley. The river is characterised as relatively narrow and contains aquatic and wetland
plants that can obscure the water from view along much of its length in the spring and a
summer.
Further information on the character of the river can be found in the Water
Framework Directive (WFD) Assessment (Amec April 2013) prepared for the planning
application and shown in Appendix A.2.
2.1.13
There are two groundwater pumping stations and boreholes operated by Affinity Water on
the site, both just north of Dacorum Way. These extract water via two boreholes for the
public supply.
2.1.14
The site contains many mature and semi-mature trees. Two groups of trees are covered by
TPOs, both these groups are north of Dacorum Way and the civic centre.
The surroundings
2.2.1
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The site directly borders Marlowes to the east. The opposite side of the road to the site is
characterised by retail and commercial uses at the northern end of the road, which are
mostly three to four storeys, with upper storeys in use for storage, offices, and residential.
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Further south, opposite the Methodists church is a Maitland House, a six storey residential
care block.
2.2.2
Marlowes has several designated heritage features. Next to Maitland House is the Grade II
listed Marlowes Baptist Church and associated vicarage building. This mid-late Baptist
church was built in an Early English Gothic style in 1861. The west elevation presents a tall
proportioned façade, with gabled roof and unusual double west windows. The heritage
significance of this building lies in its relationship with the adjacent rectory and its historic
value as evidence for diversifying religious practices in nineteenth century Hemel
Hempstead.
2.2.3
Further south on Marlowes near the south eastern corner of the site is the three storey
stucco fronted 51 Marlowes, which is Grade II listed. This building dating from about 1740,
with remodelling in the 19th century, was built as a house but is now is use as offices with a
ground floor extension added in the 20th century.
2.2.4
The boundary to the north is with Queensway and is marked by several mature/semi-mature
trees and a low wall. On the opposite side of the road is the Grade II* listed building ‘The
Bury’. This is a late eighteenth century house that holds a prominent position in the
streetscape due to its high status appearance and a lack of garden planting. However, a line
of established evergreen trees and wide pavement and low wall separate it to some degree
from the road. The building is currently in use as the local register office. To the north the
historic parkland setting of The Bury is retained as Gadebridge Park. This means the
character of the building setting is more intact from the north than it is to the south where the
site is located.
2.2.5
Gadebridge Park public open space partly borders the site to the north. The open space is
part of the biggest part in Dacorum and provides a green wedge into the centre of Hemel
Hempstead. The park offers a range of formal and informal recreation provision, including
miniature golf and lawn bowling.
2.2.6
This area covered by a designated Hemel Old Town Conservation Area extends into the
northern edge of the site. The conservation area contains the buildings of Hemel Hempstead
old town centre, which as a result of new town development moving the town centre to the
south means medieval buildings remain relatively intact. The boundary of the designated
area extends along the backyards of the buildings fronting the High Street, including the
churchyard of Grade I listed St Mary’s Church and parts of Gadebridge Park along the
western side. To the south, the conservation area includes the end of the High Street and
also The Bury to the west, along with its gardens. Many buildings in the conservation area
have listed status. The conservation area slightly overlaps the northern part of the site.
2.2.7
Other listed buildings in the conservation area closest to the site are 4 Queensway (Grade
II), dating from the 18th century, with a later 19th century, with the ground flood altered by a
modern shopfront. Also, number 6 and 8, wrought iron frontrailings (Grade II*). This late
18th century building makes a positive contribution to the streetscape, rising to a height of
three storeys. The central door is approached up a short flight of steps and framed by the
wrought iron railings, adding emphasis.
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2.2.8
The west of the site opens directly onto Leighton Buzzard Road with wide grass verges on
the college side of the road. There is very limited activity on this road. For the majority of
the length of the site, the western side of Leighton Buzzard road is characterised by the
uniform back fences of the gardens of properties on Bury Road. The majority of development
to the west of the site is residential in character, predominantly semi-detached family
houses.
2.2.9
The southern edge of the site currently links with the other buildings of the civic centre,
including the health centre and magistrates’ court. These buildings are similar in style and
age to the Dacorum Civic Centre buildings. Directly adjacent to the site boundary is an area
of managed grass open space containing mature trees and a civic centre car park.
2.2.10
Further south of the site is Hemel Hempstead town centre, with the pedestrianised shopping
area around 500m from the nearest part of the site. Also, south of Combe Street and all of
the buildings of the wider civic centre is the registered Hemel Hempstead Water Garden also
known as the Jellicoe Water Garden.
History of the Site
2.3.1
The site is situated just to the south of the old town of Hemel Hempstead. The old town
dates back to Medieval times, with the St. Mary’s parish church built in the 12 th century.
During the Medieval period the hamlet developed between the mills at Bury and Piccotts End
on the banks of the River Gade, on agricultural land owned by the monastic college of the
Bon Hommes at Ashridge.
2.3.2
During the Post-Medieval period Hemel Hempstead prospered due to the corn trade and
several buildings from the 16th to 18th centuries still survive along the High Street (north of
the site). In the 1800’s the site itself contained water-cress beds along the banks of the River
Gade. In 1890, a brick built Wesleyan Chapel (now known as Marlowes Methodist Church)
was built in the south-east corner of the site in Gothic Geometrical style.
2.3.3
In the late 19th century maps show that the site was covered by buildings of various types.
This includes short terraces of housing, pubs, a water works, the watercress beds and
various businesses. At that time Queensway was known as Bury Road. A road on-site,
Alma Road, ran parallel to Bury Street with a right angle bend before the River Gade to a
junction with Bury Road. In the south of the site there was a public baths, on the corner of
Marlowes and Bath Street, which is in a similar location to the present day Dacorum Way.
Bury Mill was north of the site, with a sluice shown on the 1898 map.
2.3.4
Following the Second World War, proposals were drawn up for the building of a New Town
attached to Hemel Hempstead, one of several in the Country. The New Town centre was
developed at the south end of Marlowes. Development at that time involved clearing existing
buildings as part of the scheme to develop the new civic centre and college for the New
Town. In the early 1960s the Civic Centre (DBC offices), designed by Clifford Culpin
Partners, were built on the southern part of the site. Construction started on the college
buildings on the north of the site in 1961. It was then known as Dacorum College, with the
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first college buildings opened in 1963. In 1991 Dacorum College merged with Watford
College and Cassio College to become West Herts College (Dacorum Campus).
Environmental Setting
2.4.1
The site is within the Hemel Hempstead urban area. The site and immediate context is a
relatively densely developed area containing various town centre uses, including shops,
offices, civic buildings and homes. Figures 3 and 4, Appendix A.1 shows the setting.
2.4.2
Flood maps for the DBC Level 2 Strategic Flood Risk Assessment (SFRA) and Environment
Agency indicate that part of the south west corner is located within the 1 in 100 year flood
outline (Flood Zone 3). The SFRA flood map also indicates that part of the site is located
within the 1 in 20 year flood outline (Flood Zone 3b - functional floodplain).
2.4.3
The River Gade runs south through the site. This stretch of the river is identified as a chalk
stream, further information about the stream can be found in the WFD Assessment,
Appendix A.2. The river’s route through the site is not in its original course, diversion was
necessary in the construction of the Leighton Buzzard Road, part of the Hemel Hempstead
new town development.
2.4.4
Upstream of the site a significant proportion of the flow of the River Gade is diverted through
a culvert via a weir to the north of the site. This diversion continues even at times of low flow
in the river. The culvert runs under the site and does not re-join the River Gade until a pond
at King’s Langley Industrial Estate, well beyond Hemel Hempstead.
2.4.5
Downsteam of the site, the River Gade channel has been straightened and widened in 19571959 and a number of weirs constructed. This allowed for the formation of a series of ponds
that form Hemel Hempstead Water Gardens, designed as part of Hemel Hempstead new
town. These gardens are Grade II listed on the Register of Parks and Gardens of Special
Historic Interest.
2.4.6
As described in section 2.2, the site has several listed buildings around it, some of which
directly face the site and proposed development. This includes The Bury, 4 Queensway and
Marlowes Baptist Church. Also, the Hemel Hempstead Old Town Conservation Area is to the
north of the site and overlaps with a small strip of the northern part of the site that helps form
the setting of the Grade II* listed The Bury. The Conservation Area covers the entire
surviving area of the medieval core of the town and includes small sections of Gadebridge
Park to the north and west.
2.4.7
Gadebridge Park is to the north of the site, with the River Gade linking the two. The park
provides a green wedge into Hemel Hempstead linking the town centre to the open
countryside. However, immediately to the north of the site the park is characterised by
Queensway car park and the grounds of The Bury, rather that public open space.
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3
The Proposed Development
Description of Proposed Development
3.1.1
A planning application is being submitted for the detailed planning permission for:

A new foodstore (Gross Internal Area (GIA) 7843m 2), with a net sales area of 3958m2,
with associated car parking;

Six pump petrol filling station (PFS) (GIA 102m 2);

A new college facility for West Herts College (GIA 9383m 2), and associated car parking;

Associated access, landscaping and the diversion of a section of the River Gade.
3.1.2
In addition, outline planning permission is being sought for new college buildings and
associated car parking in the north west corner of the site.
3.1.3
The planning application is described as:
“Hybrid application for the demolition of existing buildings and structures for a
comprehensive redevelopment of the site comprising a replacement further education
college (Use Class D1), food superstore (Use Class A1), petrol filling station (sui generis),
parking and services space, new access and vehicular bridge across the River Gade, partial
diversion of River Gade, hard and soft landscaping and other associated works [IN FULL]
and further future expansion of the college (Use Class D1) and parking and services space
(IN OUTLINE with all matters reserved, except access).”
3.1.4
3.1.5
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A selection of the key plans submitted as part of the planning application, and which should
be read with the following description of the proposed development, are included as
Appendix A.3. The appendix includes:

Site Master Plan Lower Level (Drawing number: 2011-049/025);

Site Master Plan Upper Level (Drawing number: 2011-049/026)

Proposed Elevations – Morrisons (Drawing number: 2011-049_B01/210)

Proposed Elevations – West Herts College East West Elevations (Drawing number:
2012-168_B02/206)

Proposed Elevations – West Herts College North South Elevations (Drawing number:
2012-168-B02/207)

Landscape Masterplan (Drawing number: 9012-012/102)
Appendix A.3 also contains an illustrative drawing of the site showing the layout of the
proposed development and landscaping.
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3.1.6
Development will involve the demolition of all the college buildings on the site, all parts of the
civic centre on site and the Marlowes Methodist Church. The decked ‘plaza’ to the east of
the civic buildings will be retained.
New college buildings
3.1.7
The new college buildings covered by the full planning application are located adjacent to the
corner of Marlowes and Queensway in the north east of the site. The intention is for the
corner of the building on this junction to form a landmark building. The landmark features of
the building include the upper floors of the building projecting out over Marlowes, large
windows on Marlowes and at the corner giving views into the college, which are to be framed
with bronze colour cladding.
3.1.8
The design of the college makes use of the site dropping down towards the River Gade.
This means that although the main entrance on Marlowes is at ground floor level, towards
the west there is an additional lower ground floor, accommodated due to the change in
levels. The frontage on Marlowes is approximately 13.4m above ground level (3-storeys)
and 15.9 above ground level to the west (4-storeys).
3.1.9
The building will have two wings of educational accommodation, with workshops on the
lower ground floor, support classrooms on the first floor, and other teaching and common
rooms on the second floor. The building will be organised around an internal ‘street’, which
will allow access to and views of the specialist workshops and teaching spaces.
3.1.10
The college building will have a large window on the Marlowes elevation allowing passers by
a view into the automotive workshops. The building is designed to make use of darker brick
materials on the lower floors and white rendered upper floors
3.1.11
Car parking for the college will be provided to the west and south of the main building. 72
parking spaces will be provided; all will be surface level spaces. Cycle parking will also be
provided for staff and students based on predicted needs.
3.1.12
The existing character of Queensway will be retained to the north of the college by retention
of many of the mature trees within the site that border the road. There will be also new tree
planting adjacent to the college building.
The foodstore
3.1.13
A new foodstore is proposed in the middle section of the site, south of the new West Herts
College building.
3.1.14
The foodstore will be located directly south of the college building. The orientation and
location of the building means it will be prominent on Marlowes, with other prominent
facades facing the car park and the River Gade. On the Marlowes façade the foodstore will
be two-storeys except over the entrance where it rises to three to accommodate a roof
feature. Due to the change in levels across the site the elevations on the western façade are
three storeys.
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3.1.15
The main entrance to the foodstore itself will be on Marlwoes and is to be characterised by a
canopied colonnade to reflect the scale of shop units opposite, this wraps around the
foodstore from the entrance to the eastern façade. Facing brickwork will be used at the
ground floor level to complement nearby shops. This will be broken up with glazed sections
along Marlowes that provide views into the foodstore’s entrance area, café and checkout.
3.1.16
The roof above the entrance slopes down towards the River Gade, responding to the change
in levels. The design makes use of the change in levels across the site, with the foodstore
raised on stilts utilising the space beneath as an undercroft car park, although a small
amount of additional excavation will be required. The undercroft car park will sit below street
level at Marlowes. This means a large proportion of the foodstore parking will be hidden
from view. The surface car park will be divided up into smaller areas with some new trees
interspersed.
3.1.17
A further car park will be provided, associated with the foodstore but with access only from
Marlowes. This car park will be on the decked aree that is currently the plaza of the Civic
Centre.
3.1.18
The main foodstore car parks will provide 425 car parking spaces, 4 motorcycle bays and 12
cycle hoops (24 spaces). An upper deck car park will contain 73 car parking spaces.
Appropriate provision will be made for disabled and family spaces.
3.1.19
During foodstore opening hours a travelator will operate within the foodstore entrance area,
allowing shoppers and other pedestrian’s access from the lower level car parking areas on
the east of the site, to the higher level at Marlowes and the foodstore entrance. Externally,
there will also be a staircase providing public access across the site.
3.1.20
The foodstore service yard will be on the western side of the foodstore. It is surrounded by a
3m high fence to provide security, noise attenuation and visual screening. Landscaping will
be used to soften the appearance of the fence, with planting of trees, shrubs and climbing
plants. Further landscaping will be provided along the River Gade to create a softer edge for
the foodstore.
3.1.21
It is proposed that lighting on the developed site will be turned off overnight, after the
foodstore closes, with the exception of limited security lighting.
Petrol filing station and Car Wash
3.1.22
A new 6 pump PFS associated with the new foodstore will be built on the southern part of
the site and will include a car wash and 90 sqm kiosk.
3.1.23
The PFS will include above ground fuel tanks to avoid the potential risk on the aquifer from
below ground fuel storage. These Tanks have been specifically designed to meet the
requirements set down in the new revision of the Design, Construction, Modification,
Maintenance and Decommissioning of Filling stations more common Known as “The Blue
Book”. The tanks are built to high specification and will include secondary containment to
contain any fuel leakage from the primary tank, up to and more than the full capacity of the
primary tank. The PFS will contain two 60,000 litre petrol tanks and one 120,000 diesel tank.
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3.1.24
Tanks are also designed to meet public safety requirements, with petrol tanks having a
minimum of 2 hours of fire protection, protection against impact damage from vehicles and
ballistic resistance. A further protection measure allows for a further 2 house of protection
against fire, to give 4 hours in total. As they are above ground the tanks can also be
inspected but lead detections systems will also be fitted to constantly monitor the tanks.
3.1.25
A car wash complete with foul water drainage systems is proposed as part of the PFS. It is
to be situated to the south of the main PFS. Access to the car wash will be from the main
access point from the site and through the PFS.
3.1.26
Access to the PFS will be from the main access route over the River Gade from Leighton
Buzzard Road.
Access and Highway Works
3.1.27
A new primary access will be created to the site from Leighton Buzzard Road, with a new
vehicle and pedestrian bridge crossing the River Gade. This new access will be the main
route into the site enabling access to:

Vehicle access to the foodstore car park and PFS;

Pedestrian access from the west to the foodstore;

Vehicle access to the college car parking;

Access to the Affinity Water boreholes for maintenance.
3.1.28
The new junction with Leighton Buzzard Road is designed to accommodate predicted traffic
flows associated with the site in full operational use. The junction will provide for two lanes
of southbound traffic along the most of the length of Leighton Buzzard Road between the
junctions with Queensway and Combe Street.
3.1.29
A new access will also be created from Marlowes to the retained decked car park. This has
been designed to ensure safe access based on the gradients at the site, and makes sure of
the existing Marlowes / Dacorum Way junction arrangements. However, the access to the
site provided by the Marlowes / Dacorum Way junction will be stopped up. In addition, the
current access form Marlowes to the site, to gain access to the college car park, will also be
stopped up.
3.1.30
The proposed development is designed to ensure good access for pedestrians through and
around the site. To improve access around the site the proposed development includes the
improvement of the footway along the eastern side of Leighton Buzzard Road. An east west
pedestrian link will be provided through the site. This will run from the foodstore entrance,
down to the lower level via the travelator or staircase, through a defined route within the car
park, across the new footbridge over the River Gade and to the riverside walk, or
alternatively through the car park to the main road access bridge.
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The River Gade Diversion
3.1.31
The proposed development includes the diversion of a 250 metre stretch of the River Gade
within the site.
3.1.32
Along the river corridor an 8m buffer will be kept free of built development either side of the
river channel, except for the footbridge and vehicle access bridge and riverside path.
3.1.33
The diverted river channel will be of a comparable length to the existing channel through the
site. It is to be moved slightly to the west of the existing channel for most of the river’s length
through the site. However, where the river enters and exists the site will be maintained. The
river is being diverted to accommodate the access bridge and a satisfactory layout of
development on site; more detail on the reasons for diversion can be found in section 3.4
below and the WFD Assessment in Appendix A.2. The new stretch of river will have a
gravel substrate to match the existing substrate of the river. The design of the diverted river
section incorporates a variety of bank slopes, include a two stage channel to improve flow
velocity during low flows and provide refuges for aquatic fauna.
3.1.34
The two existing footbridges across the river will be removed and replaced by a new
accessible footbridge approximately 35m north of the proposed new main access bridge.
The bridge will link to a new riverside walk will be created along the route of the River Gade.
3.1.35
The riverside walk will provide an attractive route through the site, linking Queensway to the
town centre area. The route will include a section of timber boardwalk that will cross the
wetland area created just north of the new Leighton Buzzard access junction. The wetland
area is within the part of the site in Flood Zone 3. It will consist of an area that will be wet
during higher rainfall months and two ponds (that do not connect to the River Gade). These
ponds and wetland areas will provide water storage to reduce flood risk, as well as providing
new wildlife habitats on the site. The design of the river and the proposed diversion has
been subject of discussion and consultation with the Environment Agency.
3.1.36
Lighting will be provided along the riverside walkway to for the safety of cyclists and
pedestrians. However, lighting will be designed to maintain the dark conditions that
characterise the current River Gade corridor. This will be achieved setting back lighting and
directing it away from the corridor. In addition, with the exception of essential security lights,
the lights on the site will be switched off outside operational hours. Bankside planting of
trees and shrubs will also help contribute achieving dark conditions on the east bank of the
site (away from the riverside walk).
3.1.37
The existing culvert under the site that takes part of the River Gade flow will be maintained
and protected in its current position, with suitable easement provided.
Outline proposals for additional college buildings
3.1.38
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The outline element of the scheme is for a new educational building to be used by West
Herts College. An indicative building footprint is shown on the plans in Appendix A.3 which
includes a Gross External Area (GEA) for these additional college buildings of approximately
3100m2. The site also includes space for car parking and internal landscaping.
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3.1.39
For the purposes of assessment, it is assumed that the buildings will be three storeys, i.e. up
to 13m above ground level.
3.1.40
Full permission is being sought for the access to the site. This will provide access from
Queensway to the additional college buildings covered by the outline planning application.
This junction will provide for ‘left in and left out’ movements to ensure road safety in proximity
to the Leighton Buzzard roundabout.
Landscaping
3.1.41
A Landscaping Plan has been prepared for the site to show the location of new and retained
landscape features. This includes a line of retained trees along the northern boundary of the
site adjacent to Queensway. There will also be new planting of semi-mature trees and
shrubs along the River Gade as a feature of the riverside walk.
3.1.42
A line of semi-mature trees will be planted along the boundary with Leighton Buzzard Road
to reinforce the boundary and provide some compensation for the loss of trees elsewhere on
the site.
3.1.43
Adjacent to the foodstore entrance on Marlowes a new public space will be created, this will
include hard landscaping and seating areas and new planting. The boundary between the
decked car park and public area will be defined by hedge planting with the robust shrub
planting in front. An avenue of semi-mature tree planting will be provided in this area, which
will provide interest in the area and shade for seating provided beneath. The area will have
different paving that the rest of the pavement along Marlowes to define the area. Horizontal
louvered fencing panels will screen the pump house to the west.
Utilities
3.2.1
This section summarises the current utilities at and in the immediate vicinity of the site and
proposed diversions, upgrades and disconnections for the proposed development in order
that any significant environmental impacts arising from the required utility works can be
assessed within each of the technical assessments within the EIA.
Utility Provision
3.2.2
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The site has the following existing services:

High voltage (HV) and low voltage (LV) Electrical supplies;

Natural Gas Supplies;

Mains Water Supplies;

Data and Telecoms Supplies; and

Foul and Surface Water Drainage.
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3.2.3
The proposed increase in the density of development at the site and alterations to the
highway layout means that it will be necessary to upgrade the existing utilities to reflect the
new layout proposals. The utility strategy work will coordinate the proposals.
Summary of Existing Utilities Provision
3.2.4
Electricity: Existing mains run on and around the site predominantly along Marlowes and
Queensway. Existing connections are provided from Marlowes, Queensway and Dacorum
Way. Three sub-stations exist on the site located at a) rear of the town Hall, b) just off
Dacorum Way, and c) within the college campus.
3.2.5
Gas: There are three gas links onto the site. Two are provided from the main along
Marlowes and one from the main within Queensway.
3.2.6
Mains water supplies: The existing mains network is located within the site and along
Marlowes. Supplies to each of the existing buildings are fed locally from the existing mains.
In addition there are two water extraction pumps operated by Affinity which are located just
off Dacorum Way.
3.2.7
Data and telecom supplies: Several exist in the area with mains supply routes running down
Marlowes, Queensway and along Leighton Buzzard Road. Supplies to each of the existing
facilities are fed locally from the existing mains.
3.2.8
Sewer: Separate foul and surface water drainage runs exist across and adjacent to the site.
The main run is along Marlowes and Queensway. Connections from each of the facilities are
made into the sewers.
Potential Utility Works
3.2.9
The proposed development is denser than the buildings presently within the site boundary
and there will therefore be a requirement to increase the overall utility capacity. This will be
confirmed through further utility studies, including the requirements for re-routing, extension
of existing supplies, the alignment of utilities corridors and any associated easements.
3.2.10
It is anticipated that the following utility works will be required for the proposed development:
3.2.11
Electricity:
3.2.12

Relocation and upgrading of the existing sub-station facilities to meet new demand
requirements. New supplies to be provided from the new sub-stations.

As a consequence of the closure of part of Dacorum Way, mains routes are to be
diverted / terminated.

Potential diversion works along Marlowes to enable road re-alignment.
Gas:

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Potential diversion works along Marlowes to enable road re-alignment.
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
3.2.13
3.2.14
New supplies obtained from existing mains.
Water:

Existing boreholes and are to remain although the mechanical pumphouse will be
relocated on site.

New supplies to be obtained from existing mains.

Potential diversion works along Marlowes to enable road re-alignment.
Data and telecoms:

New supplies to be obtained from existing runs.

As a consequence of the proposed new access from Leighton Buzzard Road, potential
diversions to existing required.

Potential diversion works along Marlowes to enable Road re-alignment.
Incorporated Mitigation
3.3.1
The redevelopment of the site provides an improved link between the Old Town and new
town parts of Hemel Hempstead. The new uses, which front onto Marlowes, will form a
continuum of the built character of the town along both sides of Marlowes. The new
foodstore will encourage more people north out of the new town centre towards the Old
Town.
3.3.2
The foodstore has been designed with the main entrance on Marlowes. The new foodstore
has a bespoke design, tailored specifically to the site. The main entrance to the foodstore
will be on Marlowes and will feature a canopied colonnade. Facing brickwork will be used on
the groundfloor to complement other nearby shops, which will be broken up with glazed
sections along Marlowe’s offering views into the foodstore and providing an active frontage
at street level. Upper levels will utilise lighter coloured materials to produce an effect similar
to the medieval buildings on the High Street but also continue around the building providing
a clean contemporary feel to the remaining elevations.
3.3.3
Providing an improved college at the north eastern tip of the site will ensure that footfall is
maintained all the way along Marlowes and help to support the Old Town. Reducing the
footprint of the college also opens this site up for wider regeneration and the delivery of the
foodstore development.
3.3.4
The design of the college is intended to provide a new landmark feature facing onto the Old
Town. The design and use of materials have been chosen provide a character building in
this location, with large feature windows providing an active streetscape with views into the
college.
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3.3.5
The proposed College and foodstore will be lower than the existing Dacorum Borough
Council offices that are part of the civic centre.
3.3.6
The design of the realigned section of the River Gade is designed to mimic the natural form
and hydrology of a chalk river of this type. A buffer strip is to be retained along the realigned
river to be kept free of built development and allow a more natural bankside than parts of the
river currently experience. New riverbank planting in keeping with what would be expected
of a river of this kind will be provided. The design of the new river channel will also help
provide natural features. Planting and the design of the channel should help increase the
biodiversity potential on this stretch of the River Gade.
3.3.7
New water features on the site and adjacent to the River Gade allow for the storage of flood
water helping reduce the risk of flooding at the site. This includes an area of wetland
incorporated into the development. Part of this will available for water storage during times
of heavier rainfall, but would dry out at drier times. There would also be two ponds, that will
be ‘offline’ from the river and anticipated to remain wet at all time. Areas at higher risk of
flood will be kept free of development.
3.3.8
The improved riverside path along the River Gade will be of substantial benefit to the town
by creating an attractive walking route between Gadebridge Park and the town centre. The
development also will provide enhanced walking routes along Queensway, linking the
riverside path to the Old Town. A route to the south of the site will provide future east west
pedestrian links.
3.3.9
The landscaping masterplan scheme for the site will help reduce the visual impact of the
scheme, providing screening. In addition, landscaping will help mitigate in part for the loss of
trees on the site as a result of development.
3.3.10
The petrol filling station has been designed with above ground fuel storage tanks. This
reduces the risk to the Source Protection Zone 1 (SPZ1) that underlies the site by ensuring
the tanks can be regularly inspected and maintained and therefore reduce potential for links
and remove the risk of undetected leaks.
Consideration of Alternatives
3.4.1
The EIA Regulations require an ES to include an outline of the main alternatives considered
by the applicant, indicating the main reasons for the choice made, taking into account the
environmental effects.
3.4.2
This legal requirement is expressed in very general and high-level terms, requiring only the
inclusion of an "outline" of "main" alternatives and an "indication" of "main" reasons. .
3.4.3
It is a matter for the applicant to decide which alternatives it intends to consider. The EIA
Regulations do not expressly require that an applicant considers alternatives, although it is
widely encouraged at the policy level, both European and domestic, and is a feature of EIA
best practice.
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3.4.4
The consideration of alternatives in this ES goes beyond what is required, helping to explain
how alternatives were identified and why the proposed development was chosen in
preference to them.
3.4.5
Paragraph 83 of Circular 02/99 provides the following national policy guidance on the
consideration of alternatives in EIA: "...consideration of alternatives (including alternative
sites, choice of process, and the phasing of construction) is widely regarded as good
practice, and resulting in a more robust application for planning permission. Ideally, EIA
should start at the stage of site and process selection, so that the environmental merits of
practicable alternatives can be properly considered." This policy guidance has been taken
into account when preparing this ES.
3.4.6
Alternatives should only be studied where they are feasible, realistic and genuine. This may
depend on various factors, including planning policy, land ownership, financial viability,
technical feasibility and design quality. Options which are unlikely to be acceptable or
deliverable are not realistic alternatives and so do not need to be considered.
3.4.7
Whilst environmental effects are relevant when choosing between alternatives, other factors
are also relevant. The main selection criteria which the applicant has used when choosing
between the alternatives which it has studied include: planning policy, viability, design
quality, market requirements, site constraints and opportunities and environmental effects.
3.4.8
The following provides an outline of the main alternatives studied in relation to the proposed
development and the main reasons for choosing the proposed development in preference to
them. More detail on the iteration of alternatives can be found as part of the Water
Framework Directive Assessment, Appendix A.2.
No Development & Alternative Sites
3.4.9
The principal of redevelopment at the site is set through local policy by DBC. The current
Local Plan adopted in 2004 identifies the site within Hemel Hempstead Town Centre Zone 2,
allocated for civic, educational and professional uses as part of Area Proposals for Hemel
Hempstead Town Centre.
3.4.10
The uses on the site are further developed through the emerging Core Strategy that is
nearing adoption (examination completed in late 2012). Policy CS33: Hemel Hempstead
Town Centre relates specifically to the town centre and the development that is should be
delivered.
3.4.11
The Hemel Hempstead Town Centre Masterplan has been drawn up for the whole town
centre. The masterplan was adopted as a Supplementary Planning Document (SPD) in
January 2013 to support Core Strategy policy. The masterplan identifies that the site is
within ‘The Gade Zone’. In this location the masterplan supports the more efficient use of
the site by the college so that land can be made available for alternative uses, such as a
foodstore, as part of regeneration proposals. The masterplan specifically states that there is
an opportunity to deliver a new supermarket to the northern part of the Gade Zone as part of
a comprehensive redevelopment scheme. Chapter 5 references the planning statement for
the redevelopment of the Zone, as discussed above, and states that ‘it is envisaged that a
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new college and foodstore will be part of the first phase of development. This will be followed
by a new Public Service Quarter which will accommodate a new library and other civic uses’.
3.4.12
Therefore, the conclusion of this is clear in that a ‘no development’ scenario is not
compatible with policy and therefore should not be considered as reasonable. Furthermore,
the site has been identified by policy for a foodstore and college use, therefore no alternative
sites have been considered. Further information on the policy covering the site can be found
in Chapter 6 of this ES and the Planning Statement submitted with the planning application.
Site Layout and Floorspace
3.4.13
The Masterplan for the site identifies that the Gade Zone is the main value generator in
delivery of the town centre plan as a whole. In terms of viability and phasing, the Masterplan
makes it clear in paragraph 6.4.9 that the supermarket is one of the two individual elements
that drive much of the overall value on the site and is critical in the delivery of the overall
Masterplan objectives.
3.4.14
The Retail and Leisure Study (2006) recognises the potential for the wider ‘Civic Zone’ site
(which includes the site assessed here) to accommodate a food superstore; and also notes
that it is likely to function as an ‘edge of centre’ site. The Masterplan identifies the suitability
of the site for a ‘medium sized supermarket’. The applicant has determined that a foodstore
of the proposed size can be effectively accommodated on the site to create a viable use.
3.4.15
Based on the principle of providing retail and college development at the site a number of
options for site layout were considered. There was a need to making a final decision on
layout to ensure the new foodstore was would be financially viable as this is essential to
ensure the delivery of the college on the site. When considering a layout for the foodstore
and access arrangements it was necessary for the foodstore operation (Morrisons) to
consider the features that would make for a successful foodstore in Hemel Hempstead. The
key features were determined as:
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
The foodstore is situated in a location with a demographic profile that matches the profile
of the business to attract and retain customers and staff.

A visible and prominent profile site is necessary to attract and retain customers and staff,
including enabling vehicles to leave the highway network to visit the foodstore and park
conveniently and safely.

The foodstore is of the right size to accommodate the full range of the food offer with the
right size of space to accommodate staff and associated services (IT, warehousing, staff
facilities) in order to generate sufficient turnover to justify the wider development and to
compete with other large stores in the Hemel Hempstead catchment (primarily Tesco,
Jarman Way (4,361 m2 sales and Sainsbury’s, Apsley (4,637 m2 sales).

A petrol filling station (PFS) is located close to the foodstore and visible from the
highway, in order to attract further trade and enable the foodstore to compete with other
large foodstores that include a PFS offer (i.e. Tesco and Sainsbury’s both include PFS).
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
The site is large enough to accommodate the right number of car parking spaces to meet
the demand from customers and staff, given the majority of customer visits are once a
week family shopping trips with trolleys rather than smaller convenience top up shopping
trips with a basket.

The car parking spaces need to be located in close proximity to the foodstore entrance
to satisfy customer demand and for ease of access with a fully laden trolley on
completion of the shopping visit.

The foodstore entrance is located to ensure easy customer access for both car borne
shoppers entering via the car park and customers arriving on foot, via public transport or
taxi

The site is large enough to allow safe and segregated access for delivery vehicles to
maintain stock levels within the foodstore and avoid conflict with customer access and
parking.
3.4.16
If any one of these elements does not meet expectations, then the whole business case
used to support the development is undermined and viability of the development (and
Masterplan as a whole) is put at risk.
3.4.17
Furthermore, the site contains a number of constraints that had to be considered by the site
architects in drawing up their design, these are:
3.4.18
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
River Gade running through the site;

existing sewer and culvert with 12 m easement;

two pumphouses (Affinity Water) that need to remain in place;

site is partially within a category 3a flood risk zone;

there is a downward gradient across the site from Marlowes to Leighton Buzzard Road;

Transport modelling indicates that access from Leighton Buzzard Road would have least
impact on the traffic flows in and around the town centre;

Points of access from Leighton Buzzard Road were limited due to the location of the
culvert and sewer on the site, the gradients, the need to achieve safe sightlines;

there are a number of trees located within the site, including two areas of protected
trees; and

part of the site is within the Old Town Conservation Area.
Floorspace for the college has been determined by West Herts College as part of their
improvement plans. Existing college buildings on the site are not suitable for modern
educational needs and are becoming increasingly expensive to maintain. As a result the
campus is not meeting student’s needs and falls below acceptable standards, particularly
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when compared to the college’s new campus at Watford. The college floorspace has been
determined by what is required to provide modern teaching facilities, including workshops,
and to combine the Dacorum and Kings Langley campuses.
3.4.19
Based on the features of a successful foodstore and the possible constraints on
development the architects worked through an iterative process to determine the design and
layout of the site. Although, the formulation of the final design was a process four key
options were set out during the process based on the location of the main buildings on the
site. The options were considered consecutively and the four presented below represent the
evolution of site layout. Drawings relating to each option are shown in Appendix A.3.
Option 1 – College in the north with foodstore in the south
3.4.20
The design under this option was to have the college located in the north eastern corner of
the site fronting onto Marlowe’s and Queensway, as in the final layout.
3.4.21
This meets the aspirations of DBC of having a landmark building in this location with links to
the Old Town. Under this option the foodstore would be on the southern boundary of the
site, close to the primary shopping area and new Public Service Quarter. A shared access
can be provided to the foodstore and college.
3.4.22
This scheme has several weaknesses that prevent it being taken forward. The foodstore in
this location would require building on land occupied by the Affinity water borehole pump
houses, which is not possible as these need to be retained. The site also posed difficulties
in terms of creating a viable PFS and was not preferred by the applicants.
Option 2 – Foodstore to the north and college to the south
3.4.23
This option would see the college positioned on the southern boundary of the site with
frontage on Marlowes and would be near facilities of the civic centre such as the new library.
The foodstore would occupy the north eastern boundary of the site. Again as with the
preferred layout a shared access is possible off Leighton Buzzard Road.
3.4.24
The disadvantages of this scheme are that it does not comply with DBC guidance, as they
prefer the foodstore to the south nearer the town centre and college near the Old Town.
Again, there is potential for the college buildings to clash with the easement for the Affinity
Water boreholes. Also, the college buildings would be compromised with less available
floorspace. The foodstore in this location would also require additional excavation in order
to provide the car parking necessary to make the foodstore viable. Again, the River Gade
would require diversion.
Option 3 – Foodstore central on the site without River Gade diversion
3.4.25
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This option has the college in the north eastern corner but the position of the foodstore has
changed to bring it closer to the college, both as in the preferred layout. This option puts car
parking adjacent to the southern boundary. Again, the foodstore is near the existing town
centre. The location of the buildings ensures the easement for the pump houses is protected
and also meets the DBC guidance for the location of the college. The layout of the PFS
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works effectively and access is from a single point. The main difference in this option from
the preferred layout is the River Gade requires only minor diversion.
3.4.26
However, this layout means that insufficient parking spaces can be delivered around the
foodstore to enable it to trade at viable levels. In addition all the college’s car parking would
need to be away from the buildings on the opposite bank of the River Gade. Maintenance of
the route of the River Gade also means that there is no space to get a shared access to the
college and foodstore. Further river crossings would be needed to link the car parking to the
development.
Option 4 – Foodstore central on the site with River Gade diversion
3.4.27
This is the selected option and the final iteration of the design of the scheme.
3.4.28
This retains the location of the buildings in the positions favoured by DBC, with the college
providing a landmark building on the north eastern corner of the site facing the Old Town.
Car parking for the foodstore is on the southern boundary of the site and can accommodate
easements necessary for the Affinity Water boreholes. Some of the college car parking is
located between the foodstore and the college buildings, with the diverted River Gade
providing additional land for car parking to the south.
3.4.29
The diversion of the River Gade also allows shared access to the foodstore car park, college
and foodstore service yard. Car parking spaces can also be provided to make the foodstore
trade at more viable levels as the diversion allows the foodstore service yard to be pushed
back towards the college buildings. The layout also allows for the correct positioning of the
PFS for optimal use.
3.4.30
An additional access is provided to the site from Marlowes. This provides access to a
decked car park that provides additional town centre parking.
3.4.31
This option and option 3 require the loss of TPO trees to make way for the foodstore. The
option also requires the loss of mature trees specifically to accommodate the vehicle access.
The River Gade has to be diverted under this option. However, the final design of the
realignment allows for more natural features to be added into the river, such as more natural
banksides, increasing flow rates to introduce pools and riffles and maintain and expand
existing river sections in the site to provide wetland features.
Conclusion
3.4.32
It is evident that there are strong planning policy and regeneration argument to support the
proposed land uses in the Gade Zone and on the site. Key design issues have then been
worked through, to ensure that the site can be delivered and that help protect the public
water supply, meets the needs of DBC, and creates a viable new development for the
applicants. However, this does require diversion of the River Gade through much of the
development site.
3.4.33
The distribution of the land uses has been subject to discussion with DBC and key
stakeholders, including the Environment Agency. The decision to propose to divert part of
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the River Gade has not been taken lightly but is imperative to deliver the land uses sought to
start to deliver the regeneration of this part of Hemel Hempstead town centre. Without it, the
viability of the Council’s masterplan is undermined. The scheme submitted has sought to
optimise the land uses on the site and reflect the constraints of development. Diverting the
river would enable a viable development to proceed, and on this basis the applicant has
sought to use this opportunity enhance and improve the ecological status of the River Gade.
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4
Construction and Site Management
Introduction
4.1.1
This chapter provides information on the construction of the proposed development and the
management of the construction site.
4.1.2
An important element in the control of potential adverse environmental effects during the
construction phase will be in the implementation of a Construction Environmental
Management Plan (CEMP). This will outline the arrangements and management practices
to be adopted to minimise the environmental effects of construction and which will be agreed
with the DBC prior to the commencement of construction.
4.1.3
Topic areas for the CEMP are presented in Section 4.3 below.
4.1.4
It is proposed that the requirement for such a CEMP be secured through an appropriate
planning condition.
4.1.5
In addition it is anticipated that the construction works will be signed up to the Considerate
Constructor’s Scheme, a recognised system to drive and judge the effectiveness of
construction management.
Construction Works & Programme
4.2.1
It is anticipated, subject to receipt of planning permission, that construction is expected to
start in 2014 and be completed in a year. For the purposes of this assessment it has been
assumed that first occupation of the scheme would be at the start of 2015.
4.2.2
The first stage of development will comprise of an enablement contract which will include the
diversion of the River Gade, services diversions and the demolition of the existing buildings.
The foodstore and the college will then be constructed as two further phases.
4.2.3
The construction of the foodstore and the college will involve more than one principal
contractor and teams of sub-contractors, as the college and foodstore will be constructed
separately.
4.2.4
The key construction activities are likely to include:
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
Demolition and site clearance, including the crushing of demolition materials for re-use
on site where appropriate and the felling of trees;

Realignment of the River Gade;

Excavation of undercrofts, earthworks and remediation to create development plots;

Installation of foundations including use of piling;
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4.2.5

Removal of existing footbridges over the River Gade and construction of new footbridge
and new road bridge;

Construction of building structure, cladding and glazing and internal walls and partitions;

Installation of fixtures, fitting and building services;

Utility diversions, upgrades and connections; and

External landscaping, highway and drainage works.
The realignment of the River Gade will have specific construction activities that will include:

Channel and wetland areas excavation and profiling;

Import and placement of clay for lining the dry weather channel and placement of the
gravel layer;

Construction of river features to deflect current and profile banks;

Flooding of new channels;

Planting in river and bankside;

Connection of through flows; and

Infilling of old channel.
4.2.6
The timing of activities and phasing of construction of the River Gade is key to conserving
biodiversity in the river. Construction will be in phases that will allow watering one section of
the realignment at a time to minimise turbidity associated with wetting the substrate. This
will involve connecting each upstream end in turn and allowing it to fill with water and
planting to take place, before connecting the lower end and allowing flow to the next section.
4.2.7
Both old and new channels will be maintained for a period to allow relocation of flora and
fauna, before the old channel is filled. The aim will be for work to be undertaken during the
winter to allow for flora and fauna to establish in the spring and to minimise interference with
fish spawning. More information on construction is contained in the WFD Assessment,
Appendix A.2.
Construction Management
4.3.1
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All of the construction operations carry with them a range of issues to be dealt with in their
design, preparation and execution. Due to the town centre location of the site, best practice
in construction management will be required to minimise the environmental effects and
disruption that could be caused by such a construction project. This will minimise disruption
to affected communities, businesses and services, along with the local environment and
occupiers of all early phases of the development while later phases are under construction.
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4.3.2
It is proposed to utilise a Construction Environmental Management Plan (CEMP) to manage
the impacts of construction. The CEMP will identify a range of measures, in relation to
aspects such as noise and vibration, dust and air pollution, asbestos, contaminated land,
ecology, water resources and archaeology, which will be utilised during the construction of
the proposed development. The topics are shown in Table 4.1.
4.3.3
The format of the CEMP will need to be reviewed once the construction techniques and
methodologies to be employed in the various stages of the project are confirmed. The
CEMP will identify the responsibilities of all parties involved in the design, management and
construction of the development. It is anticipated that matters a CEMP would address
include the following, as well as the construction mitigation and enhancement measures
identified in each of the topic chapters of this ES.
Table 4.1: CEMP Areas to Address
Site Constraints and Conditions
Key Duties and Deliverables
Health & safety
Contractors’ competence and procurement
Method statements and risk assessments
Contractor communication and liaison
Performance monitoring and measurement
Personal Protective Equipment (PPE) standards
Accident reporting
Contaminated Land
Compliance with Environment Agency Pollution Prevention
Guidance
Method statements for fuel storage and transfer
Personal Protective Equipment (PPE) standards
Noise & vibration
Selection of appropriate plant
Preventative & mitigation measures
Hours of operation
Monitoring
Complaints procedure
Dust & air quality
Preventative & mitigation measures
Monitoring
Remediation
Complaints procedure
Reduction
Re-use
Waste minimisation & management
Recovery
Disposal (in accordance with the Duty of Care legislation)
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Ecology
Protection of key features
Tree fencing
River Gade specific measures
Minimising night lighting in the vicinity of the River Gade
Water Resources
Protection of resources and drains
Careful usage
Storage of materials away from water features
Information to contractors on required mitigation
Emergency planning & incident
control
Incident recognition
Emergency planning
Incident control and reporting
Site Logistics & Operations
Safety & security
Site logistics
Working hours
Maintaining access
General site layout, including: access, offices, routes,
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Site Constraints and Conditions
Key Duties and Deliverables
demarcation, lighting, deliveries, storage & setdown, welfare
facilities.
Security
Plant & equipment
Construction traffic
Designated access route
Community liaison
4.3.4
Liaison meetings
Telephone helpline
Designated point of contact
The site is located within a Groundwater Source Protection Zone and therefore a system of
driven cast piling is proposed for the site that will ensure that the groundwater is protected.
More information on this is shown in Chapter 9, Ground Conditions.
Construction Traffic
4.4.1
4.4.2
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Given the town centre location of the site, the management of construction traffic will be an
important consideration to minimise the environmental effects of construction. Access &
egress to and from the site will therefore be agreed with the relevant bodies where
necessary, taking into account the following:

Demolition;

Construction overview;

Programme of works;

Phasing of the development;

Description of works;

Enabling Works;

Building Superstructure;

Fit out; and

Site provisions for contractors including welfare facilities and travel / parking
arrangements.
Loading and unloading of materials and equipment will occur within the site boundary
wherever possible, minimising the likelihood of congestion on the highways surrounding the
site. To further minimise the likelihood of congestion, strict monitoring and control of all
vehicles entering and exiting the site will be maintained by:

Setting of specific delivery dates and collection times, where feasible;

Consolidating deliveries where feasible;
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4.4.3

Using a system of ‘just in time’ deliveries;

A requirement for authorisation when visiting the site via vehicles; and

Safely maintaining pedestrian access around the site perimeter.
The proposed development will involve the closure of Dacorum Way where it passes through
the site, although the road will still be accessible to the south of the site. There may also be
weekend closures of local roads in order to establish and remove the tower cranes or to
deliver large items of building plant. In addition, road closures will be necessary in relation to
the road works and car park works at the site. This will be agreed with DBC prior to
commencement should it be required.
Construction Waste
4.5.1
4.5.2
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Waste will be produced during the construction phase of the project, and will be minimised
and managed in accordance with the Sustainability Strategy (submitted with the planning
application). The contractor(s) will be required to implement a Site Waste Management Plan
(SWMP; in accordance with the requirements of the Site Waste Management Plan
Regulations 2008) to minimise and control the waste to be disposed of. The main aims of
the SWMP will be to ensure compliance with waste legislation and to move waste up the
hierarchy, diverting as much waste as possible from final disposal to more sustainable waste
management options, i.e.:

Reduction;

Re-use;

Recovery (i.e. recycling);

Disposal (i.e. landfill/incineration); and

The SWMP will need to be consistent with the CEMP.
At this pre-planning stage a framework Site Waste Management Strategy (SWMP) has been
prepared as a draft for contractors. This SWMP forms the basis of a detailed strategy to be
prepared by the principal contractor on the site, once appointed. The SWMP will help in the
sustainable management of waste arising on the site during earthworks, demolition and
construction, it is included as Appendix A.7.
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5
Assessment Method
Introduction
5.1.1
This chapter describes the process by which the EIA was carried out. It includes a
discussion of the relevant Regulations, the EIA process, consultations, and the assessment
method.
EIA Regulations
5.2.1
Procedures relating to the assessment of the environmental effects of development are
described in The Town and Country Planning (Environmental Impact Assessment)
Regulations 2011. These implement EC Directive 85/337/EEC, as amended, into domestic
legislation. The initial Directive and its three amendments have been codified by Directive
2011/92/EU. The Regulations set out the procedures for undertaking an EIA and the
information which is required in an Environmental Statement (ES). Formal guidance on
procedures under the EIA Regulations was issued in Circular 02/99 and the Government has
also published a booklet entitled ‘Environmental Impact Assessment: A Guide to Procedures’
(November 2000).
The EIA Process
5.3.1
5.3.2
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In general terms the main stages in the EIA are as follows:

Screening – determining the need for EIA;

Scoping – identifying significant issues, determining the scope of the EIA;

Data Review – drawing together and reviewing available data;

Baseline Surveys – undertaking baseline surveys and monitoring;

Assessment & iteration – assessing likely significant effects of development, evaluating
alternatives, providing feedback to design team on potential adverse impacts, modifying
development or imposing parameters, incorporating mitigation (including monitoring and
long-term management), assessing effects of mitigated development; and

Preparation of the ES.
It should also be noted that, as summarised in section 5.5, consultation with relevant
stakeholders has been undertaken throughout the EIA process.
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Screening and Scoping
Screening
5.4.1
To determine whether the development would constitute EIA development in the context of
the EIA Regulations a formal screening opinion was sought from DBC. This set out details
relating to the location of the site and what development was proposed. The screening letter
submitted to DBC is attached as Appendix A.5, dated August 2012.
5.4.2
DBC provided a screening opinion, stating that the proposed development would be an EIA
development and assessment of likely significant environment effects would be required.
The opinion was reached as it was considered that the proposals could have significant
effects on the environment “by virtue of factors such as pollution and the risk of accidents,
having regard in particular to substances or technologies used. It would also have significant
effects on the environment by virtue of the fact that it is proposed to divert a 150m length of
the River Gade.” The screening opinion is provided in Appendix A.5.
Scoping
5.4.3
Once it was agreed that EIA would be required for the proposed development, a scoping
exercise was undertaken to identify in more detail the potentially significant environmental
issues relating to the proposed development to ensure that they were subject to an
appropriate level of assessment, thereby providing a focus for the EIA.
5.4.4
The scoping exercise involved reviewing the proposed development in relation to existing
site conditions, the team’s experience of other projects of a similar nature, potentially
significant issues perceived by the team and consultees, and the means by which they would
be assessed.
5.4.5
The findings of the scoping exercises were documented in a detailed EIA Scoping Opinion
Request (prepared by Peter Brett Associates LLP, 19th September 2012), which was
submitted to DBC. The Scoping Report is provided in Appendix A.6 and includes a letter
from DBC as well as detailed comments from the Environment Agency and others.
5.4.6
DBC EIA Scoping Opinion (dated 24th October 2012) is provided in Appendix A.6. PBA
provided a response to the scoping opinion identifying how the ES would address the
matters raised. However, PBA raised some queries regarding air quality assessment at the
site. The email exchange to resolve and agree the assessment method is provided in
Appendix A.6. Addendum sections are included in the Scoping Opinion Request to take
account of DBC’s Scoping Opinion and subsequent discussions.
5.4.7
This ES has been prepared to document the assessment undertaken in accordance with the
Scoping Report and Scoping Opinion.
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Consultations
5.5.1
A comprehensive programme of consultations has been undertaken with statutory and nonstatutory organisations as well as an extensive community engagement programme of
events and workshops with the local community. Such consultations have been to
undertaken to inform the emerging design and the EIA.
5.5.2
As part of the EIA process the following consultees have been consulted to agree the scope
of the assessment, to provide information, to discuss assessment methods and findings, and
agree mitigation measures and design responses, more detail on specific consultation is
contained in ES technical chapters. Consultees have included:

Dacorum Borough Council (DBC);

Hertfordshire County Council;

Environment Agency;

Natural England; and

English Heritage.
5.5.3
The EIA has been undertaken to fulfil the requirements of the consultees and the assistance
of these consultees is gratefully acknowledged.
5.5.4
In addition a comprehensive programme of public consultation has been undertaken. This is
summarised in Section 1.5 drawing upon the Statement of Community Involvement
submitted with the planning application.
Committed Developments
5.6.1
The EIA Regulations require the assessment to consider the likely significant effects and
cumulative effects of the proposed development in the context of other major local
developments as well.
5.6.2
DBC was consulted to identify committed developments that should be considered in this
context, however, none were identified. Although the whole of Hemel Hempstead town
centre is subject to the renewal and regeneration masterplan, adopted as SPD (see Chapter
6) The Link is the first part of the regeneration that an application has been submitted for. As
other major local developments come forward and planning applications are submitted,
whether included in planning policy or not, they should be designed and assessed in the
context of The Link proceeding (assuming grant of planning permission).
5.6.3
The scope and approach of the Transport Assessment has been agreed with the County
Council as the local highways authority. This separately agreed the elements of town centre
development that should be included in the modelling of transport effects. The transport
data utilised in this ES (within the Transport & Access, Noise & Vibration and Air Quality
chapters) has been based on this modelling.
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Assessment Assumptions
5.7.1
The following assumptions have been used to ensure that the EIA has assessed the likely
significant environmental effects of the proposed development (unless otherwise specified in
each of the technical chapters):

The proposed development considered by the EIA comprises the scheme covered by
the hybrid application for full permission for the foodstore, petrol filling station, principal
college buildings and all associated car parking. With regards to the additional college
buildings where outline permission is being sought basic parameters have been used to
define the development and the detailed scheme drawings for those areas for which
detailed permission is sought;

Construction will commence 2014 and be completed in the same year, with development
starting with site clearance in the north and moving south through the site over the
construction period;

The site will be occupied from the start of 2015;

Baseline conditions are generally considered to be current conditions at the site and
surrounding area, unless significant changes are likely to occur in a ‘no development’
scenario. Such changes are identified as appropriate within each topic chapter; and

The proposed development for which outline consent is sought will be constructed to the
maximum building heights and extents. The assessment has also considered the
maximum schedule of development (as defined in Section 3.1) for which planning
permission is sought as this is likely to lead to reasonable worst case environmental
effects (e.g. as a result of traffic generated by the scheme and the visual impact).
Assessing Effects
Introduction
5.8.1
The assessment of likely significant environmental effects assesses the likely effects of the
proposed development against baseline conditions in the same year (i.e. providing an
assessment of ‘do something’ and ‘do nothing’).
Establishing Baseline Condition
5.8.2
A range of site surveys and data collection exercises have been used to identify
environmental conditions at the site. The surveys undertaken are reported in each of the
topic chapters.
5.8.3
The assessment has been based on technical surveys and assessments, the reporting of
which is frequently too detailed and lengthy for incorporation into Volume 1 of this ES. In
such instances the technical survey and assessment reports are provided in full as an
appendix to this ES (Volume 2), with a relevant summary and the reference for the full
survey or assessment provided in the ES. The geographical scope of these appended
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surveys and assessments has been based on the likelihood for significant effects in
accordance with the scoping exercise summarised above.
5.8.4
Current conditions have been used to define baseline conditions for the assessment. This is
appropriate as there is limited potential for conditions at the site to alter without this
development proceeding between now and the proposed completion year for the
development.
Assessing Operational Effects
5.8.5
To provide a robust assessment and one that is generally consistent between topic chapters,
the EIA has focused on assessing the environmental effects of the full, completed
development. Therefore the EIA has generally assessed the likely effects at the end of
construction, the year the development is proposed to be completed and fully
occupied/operational. This approach ensures that maximum exposure is considered as well
as the full environmental effects of development itself.
5.8.6
The Transport and Access chapter of the ES has been based on the Transport Assessment
(TA). The TA has been prepared in accordance with Department for Transport (‘Guidance
on Transport Assessment’, 2007) guidelines.
5.8.7
A notional future design year is used to assess the effects in some instances. This is used
where there is a need to consider effects once the site has become established and
landscaping has been given time to mature. Where this is the case it is identified in the
relevant ES technical chapter.
Assessing Construction Effects
5.8.8
The EIA has also assessed the potentially significant environmental effects that could occur
during the construction phase. These effects will vary substantially during the construction
process therefore judgements have been made to ensure that reasonable worst case effects
are tested through consideration of the processes most likely to lead to significant effects.
5.8.9
Construction effects should be temporary and the construction timetable is anticipated to be
within a year. Construction effects should also be intermittent, i.e. they will not occur
continually in one place throughout the duration of the construction works. This will have an
impact on the significance of effects and where necessary is identified in relevant ES
chapters.
5.8.10
In judging the significance of construction effects it has been assumed that the construction
mitigation measures identified and the proposed CEMP are fully implemented (as it is
expected would be required by a suitable planning condition).
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Uncertainty
5.9.1
The prediction of future effects inevitably involves a degree of uncertainty. Where
necessary, the topic chapters describe the principal factors giving rise to uncertainty in the
prediction of environmental effects and the degree of the uncertainty.
5.9.2
Confidence in predictions has been engendered by employing accepted assessment
methodologies, e.g. Design Manual for Roads and Bridges and the Guidelines for Ecological
Impact Assessment in the UK. Uncertainty inherent within the prediction has been
described. As a general principle the ES has described credible, worst case foreseeable
events and their effects.
5.9.3
Uncertainty also applies to the success or otherwise of measures to mitigate adverse
environmental effects. Where the success of a mitigation measure is uncertain, the extent of
the uncertainty has been identified in the ES and a suitable response identified.
Mitigation of Adverse Effects
5.10.1
The incorporation of mitigation measures; that is measures to avoid minimise or compensate
for adverse effects, is an integral part of the design and related EIA process. A description
and the significance of any likely residual effect, namely that which remains after mitigation
has been incorporated, is presented in each topic chapter.
5.10.2
Key mitigation measures that have been incorporated into the proposals as a result of the
EIA are identified in Section 3.3.
Residual Effects
5.11.1
Residual effects are the environmental effects that will remain after the incorporation of
mitigation measures.
5.11.2
It is these residual effects which should be considered when assessing the significance of
the proposed development, rather than the unmitigated effects as unmitigated effects will not
occur and only mitigated effects would be experienced. For instance, where a visual impact
may remain despite a landscaping scheme being implemented and becoming established.
However, clearly these impacts can be both positive and negative.
5.11.3
To provide an objective assessment of residual effects the significance of residual effects
has been determined and is identified in the ES. This allows for comparison of effects
between topics and also strengthens the assessment of impact interactions.
Significance Criteria
5.12.1
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The two principal criteria for determining significance of an environmental effect are the
magnitude of the effect and the sensitivity of the receptor; in addition the likelihood of the
effect occurring is also considered as appropriate. The approach to assessing and assigning
significance to an environmental effect has relied upon such factors as: consideration of the
EIA Regulations, guidelines, standards or codes of practice, the advice and views of
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statutory consultees and other interested parties, and expert judgement. The following
questions have been relevant in evaluating the significance of potential environmental
effects:
5.12.2

Which risk groups are affected and in what way?

Is the effect reversible or irreversible?

Does the effect occur over the short, medium or long term?

Is the effect permanent or temporary?

Does the effect increase or decrease with time?

Is the effect of local, regional, national or international importance?

Is it a positive, neutral or adverse effect?

Are health standards or environmental objectives threatened?

Are mitigating measures available and is it reasonable to require these?
Specific significance criteria have been prepared for each specialist topic, based on the
generic criteria, for adverse and beneficial effects, set out in Table 5.1.
Table 5.1: Generic Significance Criteria
Significance
Level
Criteria
Severe
Only adverse effects are assigned this level of importance as they represent key factors
in the decision-making process. These effects are generally, but not exclusively,
associated with sites and features of international, national or regional importance. A
change at a regional or borough scale site or feature may also enter this category.
Major
These effects are likely to be important considerations at a local or borough scale but, if
adverse, are potential concerns to the project and may become key factors in the
decision-making process.
Moderate
These effects, if adverse, while important at a local scale, are not likely to be key
decision-making issues. Nevertheless, the cumulative effect of such issues may lead to
an increase in the overall effects on a particular area or on a particular resource.
Minor
These effects may be raised as local issues but are unlikely to be of importance in the
decision-making process.
Not
Significant
No effect or effect which is beneath the level of perception, within normal bounds of
variation or within the margin of forecasting error.
Cumulative Effects
5.13.1
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As is explained above the potential effects of the development covered by both the outline
and full elements of the planning application have been considered collectively as the
proposed development. This has been done to ensure that the environmental effects of The
Link, Hemel Hempstead development can be fully understood.
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5.13.2
Section 5.6 above identifies that DBC has not identified any local major committed
developments in the area that need to be considered by the EIA. As a result the EIA has
considered the potential cumulative effects only of the proposed development. It will be up
to future applicants near the site to take into account The Link, Hemel should it receive
planning permission.
Impact Interactions
5.14.1
Chapter 17 of the ES provides the assessment of impact interactions, i.e. receptors being
affected by more than one environmental effect and therefore potentially being subject to a
more significant combined effect than the individual effects reported in each of the topic
chapters.
5.14.2
The approach adopted in the assessment is in accordance with the methodology set out
above, with further details provided in Chapter 17.
5.14.3
Chapter 17 therefore provides an overall summary of the effects of the proposed
development during construction and operation, and provides an overall judgement on the
beneficial or adverse environmental effect of the development.
Water Framework Directive Assessment
5.15.1
An assessment under the Water Framework Directive 2000 (WFD) has also been
undertaken for the site. This WFD Assessment is separate from the EIA process but
intrinsically linked.
5.15.2
Under the WFD, the assessment is required to demonstrate that the diversion of the River
Gade, as proposed by this development, would not compromise the current or future status
of the river. The WFD assessment considers the questions:

At the water body level, on a non-temporary basis, will the diversion result in
deterioration in the status of any elements, e.g. reduction from good to moderate status?

Will the option prevent the water body achieving good ecological status?

Can the scheme assist in the delivery of any River Basin Management Plan measures to
help achieve compliance?
5.15.3
The proposed diversion is assessed using guidance from the Environmental Agency (EA)
(Ref 488_10_SD01 and SD02), and consultation with the Environmental Agency, to ensure it
complies with the WFD. Full information on the methodology followed the purpose of the
WFD Assessment and the extensive consultation with the EA is included as Appendix A.2.
5.15.4
The WFD Assessment process has cross cutting issues for the ES, with elements of the
assessment relevant to the ES chapters on Hydrology and Drainage, Ground Conditions and
Ecology. Each of these chapters cross-references the WFD Assessment where necessary
to provide a comprehensive coverage of the potential for significant environmental effects
arising from the diversion.
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6
Planning and Policy Context
Introduction
6.1.1
This chapter provides a summary of planning policy considerations for the proposed
development. It includes reference to national and local adopted and emerging policy
guidance, and has been prepared in parallel with the standalone Planning Statement
submitted with the planning application to which the reader should refer should further
information be required.
Key policy documents
6.1.2
The site is located within the Dacorum Borough. The planning policy for the proposed
development comprises national planning policy and the adopted Local Plan saved policies.
There is also an emerging Core Strategy for the borough that is at a relatively advanced
stage, with consultation closing in March 2013 on the post examination changes to the Core
Strategy and a report of consultation prepared dated April 2013. Therefore, this can form a
material decision for determining planning applications.
6.1.3
There is also guidance on development at the site and the wider Hemel Hempstead town
centre area that has been prepared by the DBC.
6.1.4
The regional tier of planning was removed in January 2013 with the revocation of the East of
England Regional Spatial Strategy. Five policies are saved from the Hertfordshire Structure
Plan 1991-2011 (1998) that provide some sub-regional planning policy for the County.
However, none relate to the proposed development type or location, more detail can be
found in the Planning Statement submitted as part of the application.
6.1.5
The following sections set out the overall planning framework relevant to the proposed
development, rather than to identify each policy that may need to be considered. In this ES
the individual technical chapters each review the national legislation and planning policies
that may be relevant to that discipline.
National Policy
6.2.1
National planning policy is provided by the National Planning Policy Framework (NPPF –
Department for Communities and Local Government (DCLG), 2012), which was published
on 27th March 2012.
6.2.2
The NPPF replaces and revokes a raft of previous national guidance, including planning
policy guidance (PPGs), planning policy statements (PPSs) and circulars, with one
consolidated statement of national planning policy.
6.2.3
The NPPF makes the key points relevant to the proposed development, these relate to:

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Sustainable development;
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
Vitality of town centres;

Community facilities;

Sustainability transport;

Sustainable construction;

Conserving and enhancing the natural environment; and

Requiring good design.
Sustainable Development
6.2.4
The NPPF states at paragraph 14:
“At the heart of the National Planning Policy Framework is a presumption in favour of
sustainable development, which should be seen as a golden thread running through both
plan-making and decision-taking.
For decision-taking this means:
 Approving development proposals that accord with the development plan without delay;
and
 Where the development plan is absent, silent or relevant policies are out ‑of‑date,
granting permission unless:
 any adverse impacts of doing so would significantly and demonstrably outweigh the
benefits, when assessed against the policies in this Framework taken as a whole; or
 specific policies in this Framework indicate development should be restricted.”
6.2.5
Additionally, at paragraph 17, the NPPF includes core planning principles and states, inter
alia, that planning “should proactively drive and support sustainable economic development
to deliver the homes, business and industrial units, infrastructure and thriving local places
that the country needs. Every effort should be made objectively to identify and then meet the
housing, business and other development needs of an area, and respond positively to wider
opportunities for growth.”
Vitality of town centres
6.2.6
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In order to ensure the vitality of town centres, paragraph 23 states that planning policies
should be positive, promote competitive town centre environments and set out policies for
the management and growth of centres over the plan period. It sets out a series of matters
that should be considered by local authorities when drawing up local plans including
promoting competitive town centres that provide customer choice and a diverse retail offer
and which reflect the individuality of town centres; allocating a range of suitable sites to meet
the scale and type of retail, leisure, commercial, office, tourism, cultural, community and
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residential development needed in town centres – it is important that needs for retail, leisure,
office and other main town centre uses are met in full and are not compromised by limited
site availability - and allocating appropriate edge of centre sites for main town centre uses
that are well connected to the town centre where suitable and viable town centre sites are
not available.
Community Facilities
6.2.7
Paragraph 70 states that in order to deliver social, recreational and cultural facilities and
services the community needs, planning policies and decisions should plan positively for the
provision and use of shared space, community facilities (such as local shops, meeting
places, sports venues, cultural buildings, public houses and places of worship) and other
local services to enhance the sustainability of communities and residential environments;
and ensure that established shops, facilities and services are able to develop and modernise
in a way that is sustainable, and retained for the benefit of the community.
Sustainable Transport
6.2.8
6.2.9
Paragraph 32 confirms that all developments that generate significant amounts of movement
should be supported by a Transport Statement or Transport Assessment. Plans and
decisions should take account of whether:

The opportunities for sustainable transport modes have been taken up depending on the
nature and location of the site, to reduce the need for major transport infrastructure;

Safe and suitable access to the site can be achieved for all people; and

Improvements can be undertaken within the transport network that cost effectively limit
the significant impacts of the development. Development should only be prevented or
refused on transport grounds where the residual cumulative impacts of development are
severe.
Paragraph 34 adds that decisions should ensure developments that generate significant
movement are located where the need to travel will be minimised and the use of sustainable
transport modes can be maximised.
Sustainable construction
6.2.10
In determining planning applications, paragraph 96 states that local planning authorities
should expect new development to take account of landform, layout, building orientation,
massing and landscaping to minimise energy consumption.
6.2.11
Also, paragraph 99 adds that new development should be planned to avoid increased
vulnerability to the range of impacts arising from climate change. When new development is
brought forward in areas which are vulnerable, care should be taken to ensure that risks can
be managed through suitable adaptation measures, including through the planning of green
infrastructure.
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Conserving and enhancing the natural environment
6.2.12
6.2.13
Paragraph 118 confirms that local planning authorities, when determining planning
applications, should aim to conserve and enhance biodiversity by applying principles which
include:

If significant harm resulting from a development cannot be avoided (through locating on
an alternative site with less harmful impacts), adequately mitigated, or, as a last resort,
compensated for, then planning permission should be refused; and

Opportunities to incorporate biodiversity in and around developments should be
encouraged.
Paragraphs 123 to 125 state that planning decisions should aim to avoid noise from giving
rise to significant adverse impacts on health and quality of life as a result of new
development; ensure that any new development in Air Quality Management Areas is
consistent with the local air quality action plan; and limit the impact of light pollution from
artificial light on local amenity, and nature conservation.
Conserving and enhancing the historic environment
6.2.14
Paragraph 128 says that in determining applications, local planning authorities should
require an applicant to describe the significance of any heritage assets affected, including
any contribution made by their setting. The level of detail should be proportionate to the
assets’ importance and no more than is sufficient to understand the potential impact of the
proposal on their significance. Where a site on which development is proposed includes or
has the potential to include heritage assets with archaeological interest, local planning
authorities should require developers to submit an appropriate desk-based assessment and,
where necessary, a field evaluation.
Requiring good design
6.2.15
Paragraph 58 emphasises that planning policies and decisions should aim to ensure that
developments optimise the potential of the site to accommodate development, create and
sustain an appropriate mix of uses (including incorporation of green and other public space
as part of developments) and support local facilities and transport networks; and will function
well and add to the overall quality of the area, not just for the short term but over the lifetime
of the development.
Local Policy
Dacorum Borough Local Plan 2004
6.3.1
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The Dacorum Borough Local Plan was adopted in 2004 and is ’saved’ virtually in its entirety
until it is superseded by the Local Development Framework (LDF). The Local Plan sets out
the Borough Council’s planning policies and proposals for the period up to 2011 in
accordance with the Hertfordshire Structure Plan Review 1991-2011.
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Principle of development
6.3.2
On the Proposals Map that accompanies the Plan, the site falls within the Town Centre. The
Hemel Hempstead Town Centre Strategy identifies the site within Zone 2, which is allocated
for civic, educational and professional uses, as well as residential development. A small part
of the northern area of the site falls within the Hemel Hempstead High Street Conservation
Area and an Area of Archaeological Significance borders the site at its north-eastern tip.
6.3.3
The Masterplan and Gade Zone planning statements provide more detailed guidance for
what should be delivered at the site (see Section 6.4).
Town centre retail uses
6.3.4
The Local Plan supports a mix of uses in Hemel Hempstead town centre, Policy 9 sets out
the uses that are expected in town centres. This is supported by Policy 39 that defines town
centres as locations where the development of a broad range of compatible uses will be
permitted. These include, amongst others, shopping, social and community uses and
residential use.
6.3.5
Policy 42 sets out the type of retail development that will be permitted in town centres,
specifying that it is must be compatible with the size and function of the centre and the
centre’s historic and/or architectural character. Compatibility will be determined, amongst
other things, by the massing of buildings and how well vehicle movements and car parking
can be made to fit with the character of the local area.
6.3.6
Retail development is directed to the town centres of the borough, through a sequential
approach to site selection, as set out in Policy 38.
6.3.7
Policy 41 prioritises new retail development in town centres, in accordance with the
sequential approach to site selection (Policy 38). Development schemes in town centres are
encouraged which:
6.3.8
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
Are of a scale appropriate to the size, function and character of the centre (Policy 40);

Add to the range, variety and choice of shopping;

Improve the quality of the shopping environment;

Refurbish or reuse existing buildings;

Where appropriate improve accessibility of the centre by a choice of a means of
transport.
However, the location of the proposed development does not fall within either the main
shopping or mixed frontages shopping areas, as defined under Policy 42.
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Educational uses
6.3.9
As identified Policy 39 includes community uses amongst suitable town centre uses. Policy
67 states the importance of providing social and community facilities to meet the needs of all
sections of the community. Policy 68 allows for the provision of alternative provision of
community facilities if they are to be lost through proposed development, as is the case on
the site. More specifically Policy 69 permits colleges to be developed on sites in existing
town centres, subject to considerations such as car parking and retention of local character.
Design of development
6.3.10
6.3.11
Policy 10 of the Local Plan seeks to optimise the use of urban land. It states that vacant or
underused land and buildings should be brought into the appropriate use(s). Proposals for
new development will be judged against the following principles to secure the optimum use
of land in the long term:

All development must be planned and implemented in a co-ordinated way, taking a
comprehensive view of potential development opportunities in the immediate area
wherever possible;

General building development should be designed to achieve the maximum density
compatible with the character of the area, surrounding land uses, and other
environmental policies in the Plan;

Development should be accessible by a range of transport options, including passenger
transport; and

Development will be permitted if it makes optimum use of the land available, does not
prevent other land coming forward for development in the future, and is part of a
comprehensively planned development framework.
Policy 11 provides more detail on the DBC’s expectation that all development proposals are
of a high standard. Applicants will be required to provide sufficient information and
appropriately detailed plans to enable DBC to judge the full impact of the development
proposal, for instance relating to context, access, parking and pollution. Special impact
studies or environmental assessments may be required in some cases. As part of
considerations Policy 12 requires all applications to demonstrate capacity of existing and
potential infrastructure to absorb further development.
Heritage
6.3.12
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Policy 120 highlights the importance of development proposals in and near conservation
areas respecting local character and should be carried out in a manner which preserves or
enhances the established character or appearance of the area. Similarly, Policy 119 seeks
to ensure that development which could affect the character of listed buildings be designed
to maintain their setting, through the scale of proposed buildings, appearance and choice of
material.
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Flooding
6.3.13
Policy 107 states that a precautionary approach to flood risk will be taken when considering
development based on the sequential approach set out in PPG25 (since superseded by
PPS25 and most recently the NPPF). New building works within areas of high flood risk will
only be permitted in, inter alia, urban areas where appropriate flood defence measures are
included. A Flood Risk Assessment will be required for all sites where the Environment
Agency advises that the risk of flooding exists.
Draft Dacorum Core Strategy, June 2012
6.3.14
The Dacorum Core Strategy is currently in preparation; the Pre-Submission draft was
published in October 2011 for public consultation. The List of Proposed Amendments was
incorporated in June 2012 prior to the Examination in Public which commenced in early
October 2012. Since that time DBC have consulted on the Modifications to the PreSubmission Core Strategy (January 2013). The Core Strategy, once adopted, will establish
the overall pattern of development across the Borough up to 2031.
6.3.15
The Core Strategy is therefore significantly advanced and therefore is a material
consideration in the determination of planning applications. The relevant objectives and
policies are outlined in this section.
Principle of development
6.3.16
Policy CS1 relates to the distribution of development and identifies Hemel Hempstead as the
principal focus for homes, jobs and strategic services. It emphasises the importance of
enhancing the vitality and attractiveness of the town centre in accordance with Policy CS33
on Hemel Hempstead.
6.3.17
Policy CS4 sets out what development is appropriate in town centres and this includes
shopping uses and social and community uses. Mixed use development will be supported
where it supports the principles of sustainable development and does not conflict with other
policies.
6.3.18
Local objectives for the town centre include creating a new college and supermarket as well
as a better public footpath network. The Core Strategy identifies ‘The Gade Zone’ that
includes the site of proposed development as holding significant regeneration opportunities
for educational, civic, residential and multi-cultural uses.
6.3.19
Policy CS33 relates specifically to Hemel Hempstead’s Town Centre and states that new
development will contribute fully to the achievement of town centre uses, movement and
design principles and meet relevant opportunities for zones within the town centre. The
policy adds that a Town Centre Masterplan will be prepared to elaborate on this policy and
this is now adopted as an SPD (see Section 6.4).
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Town centre and retail development
6.3.20
Policy CS16 stipulates that new retail development will be assessed in terms of its location,
scale and impact. Most retail development will be directed to the town and local centres and
it will be permitted if it accords with the retail hierarchy and the sequential approach. Hemel
Hempstead, as a Principal Town Centre, will be the main destination for comparison goods,
shopping, leisure, entertainment, civic and cultural activities.
Design of development
6.3.21
Policy CS10 expects the design of all new development to follow the ‘3 step Approach to
Successful Design’ and should, amongst other things promote higher densities in and
around town centres, and deliver landmark buildings at movement and pedestrian gateways
and enhance focal points with high quality architecture.
6.3.22
Policy CS11 states that development should:
6.3.23

Respect and enhance the typical density of character areas, spaces between buildings
and the general character of neighbourhood areas;

Strengthen streetscape transitions and linkages between character areas;

Protect or enhance significant views within character areas;

Integrate with the character of the existing street pattern; and

Incorporate natural surveillance to deter crime and the fear of crime.
Policy CS29 sets out the Council’s approach to sustainable design and construction. New
development should normally comply with identified principles, including: providing an
adequate means of water supply, surface water and foul drainage; minimising impermeable
and lighter coloured surfaces within urban areas; and providing on-site recycling facilities for
waste.
Built heritage
6.3.24
Policy CS25 confirms that all development should help conserve and enhance Dacorum’s
natural and historic landscape. Proposals will be assessed for their impact on landscape
features to ensure that they conserve or improve the prevailing landscape quality, character
and condition.
Natural environment
6.3.25
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The Core Strategy specifically sets out policy that relates to better public access and links
through greenspace and the greater range of use in urban greenspace, this is covered by
Policy CS26.
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6.3.26
Policy CS31 addresses water management stating that water will be retained in the natural
environment as far as possible. Measures to restore natural flows in the river systems and
the water environment will be supported. Development will be required to avoid flood zones
2 and 3, minimise water runoff, secure opportunities to reduce the cause and impact of
flooding, and avoid damage to groundwater source protection zones.
Transport
6.3.27
Policy CS8 sets out the Council’s approach to sustainable transport. It stipulates that all new
development should contribute to a well-connected and accessible transport system that
prioritises pedestrians and cyclists. Policy CS9 states, inter alia, that the traffic generated
from new development must be compatible with the location, design and capacity of the
current and future operation of the road hierarchy, taking into account any planned
improvements and cumulative effects of incremental developments.
Supplementary Planning Documents and Guidance
6.4.1
Supplementary and guidance documents have been prepared for DBC that set out the type
and form of development that should be delivered in Hemel Hempstead town centre,
including on the site. The Supplementary Planning Documents (SPD) provides policy
guidance for delivering development.
Hemel Hempstead Town Centre Masterplan SPD, 2013
6.4.2
The Hemel Hempstead Town Centre Masterplan was published in January 2013 and is
adopted as SPD to support of local policy. It replaces the earlier Hemel Hempstead Civic
Zone Development Brief SPD.
6.4.3
The document splits the town centre in to a series of zones, as defined by the Core Strategy.
As before the site sits in the Gade Zone, which is described as containing “… a number of
large buildings that are vacant, under-utilised or no longer suitable for modern requirements.
There are also two large vacant sites in the form of the Market Square and the site of the
former “Dacorum Pavilion”. Buildings tend to be poorly related to the wider streetscape and
the River Gade, the public realm is generally poor and both east-west and north-south
pedestrian and cycle routes are inadequate.” (Para 2.9.1)
6.4.4
The masterplan indicates that there is a significant opportunity to regenerate this zone in part
due to high level of public sector ownership. Regeneration would deliver new educational
and civic facilities, alongside retail and residential space. The key strength of the zone is
considered to be its location near the heart of the town centre. The masterplan specifically
states that there is opportunity to deliver a new supermarket to the north zone as part of a
comprehensive redevelopment scheme.
6.4.5
Regeneration of the area can therefore help the north and south of the town centre become
better connected particularly through the delivery of the River Gade riverside paths. The
masterplan recognises the restrictions of development at the site due to the floodplain and
the groundwater protection zone.
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6.4.6
The masterplan specifically identifies the opportunity to deliver a new supermarket in the
north of the Gade Zone as part of a comprehensive redevelopment scheme.
Gade Zone Planning Policy Statement (GZPPS), 2012
6.4.7
This policy statement has been prepared by the Council on the broad policy, development
and design framework for the Gade Zone in Hemel Hempstead. The GZPPS is neither a
development plan document nor a supplementary planning document, but it is a material
consideration in the determination of planning applications in the Gade Zone. It was
produced in parallel with the current Masterplan to kick start the regeneration process and
help deliver a comprehensive guide for prospective developers.
6.4.8
Development proposals will be expected to follow the principles established within this
document. The GZPPS firstly sets out the constraints to the development of the Gade Zone,
which is divided into the northern, central and southern areas. It then outlines the
constraints to development across the zone; namely the River Gade, the groundwater
Source Protection Zone, utilities running under the Dacorum Way, access from the
Marlowes, and protected trees.
6.4.9
The statement indicates a number of uses which are considered to be appropriate. These
include:
6.4.10
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
Civic uses;

Retail;

Education;

Car parking; and

Residential.
With specific regard to the retail uses, the GZPPS confirms that there is a need for additional
convenience goods floorspace in Hemel Hempstead and that the Gade Zone is a preferable
location. It goes on to state that a new foodstore should be positioned in the southern area
of the Gade Zone. However, it then states that “land ownership arrangements between
Market Square and Combe Street, which were a serious issue during the Waterhouse
Square Project affecting the deliverability of the project, mean that it is unlikely that the
supermarket will be located there. The next best option is the land immediately north of
Combe Street (in the central area of the Gade Zone). It is noted that market drivers may
also affect the location since supermarkets require a sizable site with direct access and
views from the main vehicular route.” (Para. 8.18)
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Summary
6.5.1
The principle of development at the site is supported through policy. Hemel Hempstead is
identified as a location in need of regeneration with the area that includes the site being
identified as the Gade Zone. Within this zone there is support of development for a mix of
uses, including retail and retention of college facilities.
6.5.2
Development at the site will need to be designed in a way that respects the character of the
area. This will include conserving the character of the adjacent Old Town Conservation Area
and the listed buildings near and adjacent to the site.
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7
Hydrology and Drainage
Introduction
7.1.1
The chapter prepared by Weetwood Services Ltd (“Weetwood”) presents information related
to surface water (hydrology), groundwater (hydrogeology) and flood risk, as part of the EIA of
The Link, Hemel Hempstead.
7.1.2
The potential environmental impacts associated with the issues covered in this chapter cross
over with parts of the ES and should therefore be read in conjunction with Chapter 8
(Ecology and Nature Conservation), Chapter 9 (Ground Conditions) and associated reports,
as well as the Water Framework Directive (WFD) Assessment in Appendix A.2.
7.1.3
Information has been collected from a variety of sources to provide a baseline review of
hydrology and hydrogeology.
7.1.4
Informed by the baseline assessment, receptors of potential environmental effects
associated with surface and sub-surface hydrology arising from the proposed development
have been identified. Mitigation measures have been identified and residual effects
evaluated.
7.1.5
The assessment covers the construction and operational phases of the proposed
development.
Policy Context
7.2.1
There is a wide range of international and national legislation relevant to the assessment of
potential impacts to hydrology and drainage. In addition, there are many guidance
documents concerned with mitigating potential impacts. Relevant documents are listed in
Table 7.1.
Table 7.1: Relevant Key Legislation, Policy and Guidance Documents
Context
Legislation, Policies and Guidance Documents
Water Framework Directive 2000/60/EC
The Groundwater Directive 80/68/EEC
International
EC Dangerous Substances Directive 76/464/EEC and daughter directives
EC Freshwater Fish Directive 76/659/EEC and daughter directives
Drinking Water Directive 80/778/EEC
The Water Act 2003
The Water Environment (Water Framework Directive) (England and Wales)
Regulations 2003
National
The Control of Pollution (Oil Storage) (England) Regulations (2001)
The Groundwater Regulations 1998
The Surface Waters [Dangerous Substances (Classification)] Regulations 1998
Control of Substances Hazardous to Health (COSHH) Regulations (1998)
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Context
Legislation, Policies and Guidance Documents
The Environment Act 1995 (as amended)
The Surface Water (River Ecosystem) (Classification) Regulations 1994
The Water Resources Act 1991 (as amended 2003)
The Land Drainage Act 1991 (as amended)
Food and Environment Protection Act, 1985
The National Planning Policy Framework, 2012
WEBTAG Unit 3.3.11 The Water Environment Sub-Objective
CIRIA Report 648 (2006) Control of water pollution from linear construction
sites
CIRIA Report 609 (2004) Sustainable Drainage Systems – Hydraulic, structural
and water quality advice
CIRIA Report 532 (2001) Control of water pollution from construction sites
CIRIA Report 522 (2000) Sustainable urban drainage systems – design manual
for England and Wales
CIRIA Report 156 (1996) Infiltration Drainage – manual of good practice
CIRIA Report 142 (1994) Control of Pollution from Highway Drainage
Discharges
Code of Good Agricultural Practice for the Protection of Water (the “Water
Code”) (DEFRA 1998 as amended 2002)
Guidelines for the use of herbicides on weeds in or near watercourses and
lakes (DEFRA 1995 PB2289)
Environment Agency (EA) Pollution Prevention Guidelines (PPG), the most
relevant being:
• PPG 1 – General guide to water pollution and prevention;
• PPG 2 – Above ground oil storage tanks;
• PPG 3 - Use and design of oil separators in surface water drainage systems;
• PPG 5 – Works in, near or liable to affect watercourses;
• PPG 6 – Working at construction and demolition sites;
• PPG 8 – Safe storage and disposal of used oils;
• PPG 21 – Pollution incidence response planning;
• PPG 22 – Dealing with spillages on highways; and
• PPG 23 – Maintenance of structures over water.
Dacorum Borough Council Core Strategy, Submission Draft, June 2012
Dacorum Borough Council Core Strategy, Modifications to the Pre-Submission
Core Strategy, January 2013
Dacorum Borough Council Core Strategy Policies CS31 - Water Management
and CS32 Air, Soil and Water
Local
Dacorum Borough Local Plan, adopted April 2004
Dacorum Borough Council, Local Plan Saved Policies 107 - Development in
Areas of Flood Risk and 124 - Water Conservation and Sustainable Drainage
Systems
Gade Zone Planning Statement, April 2012, Dacorum Borough Council
Hemel Hempstead Town Centre Masterplan 2011-2021, Adopted January
2013, Dacorum Borough Council
Environment Agency, Thames River Basin Management Plan, 2009
Other sources of
information
Environment Agency, Thames Catchment Flood Management Plan, 2010
Environment Agency, Colne Catchment Abstraction Strategy, 2007
Dacorum Strategic Flood Risk Assessment, 2007, 2008
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Context
Legislation, Policies and Guidance Documents
National River Flow Archive
EA website
Water Framework Directive, 2000
7.2.2
The aim of the WFD is to establish “good ecological and chemical status in all surface waters
and groundwaters.” It also promotes the importance of sustainable water use. During the
implementation process, Local Planning Authorities (LPA) must not act in a way to
compromise the aims of the WFD. The WFD enables LPAs to enforce the control of diffuse
pollution at source. The development proposals must not compromise the potential for
delivering targets or actions set out in River Basin Management Plans (RBMP).
The Flood and Water Management Act, 2010
7.2.3
The Flood and Water Management Act 2010 (FWMA) implements several key
recommendations of Sir Michael Pitt’s Review of the Summer 2007 floods and presents a
new approach to the implementation and management of Sustainable Drainage System
(SuDS) including a new approvals and adoption process whereby planning applications for
new development would have to be accompanied by a SuDS application which will be
assessed by a SuDS Approval Body (SAB).
Water Resources Act, 1991
7.2.4
The Water Resources Act 1991 sets out the regulatory controls and restrictions that provide
protection to the water environment through controls on abstractions, impounding and
discharges, as well as identifying, amongst other things conservation, water quality and
drought provisions. The Act is supplemented by The Environment Protection Act 1991 which
established the Environment Agency and The Environment Act 1995 which provides for
integrated pollution control.
National Planning Policy Framework, 2012
7.2.5
The National Planning Policy Framework (NPPF) (CGL, 2012a) sets out the government’s
planning policies for England and how these are expected to be applied. The NPPF guides
LPAs and decision-takers both in drawing up plans and as a material consideration in
determining applications. It includes policies to ensure that flood risk is taken into account at
all stages in the planning process to avoid inappropriate development in areas at risk of
flooding, and to direct development away from areas of highest risk. In exceptional
circumstances where new development is necessary in flood risk areas the policy also aims
to make it safe, without increasing flood risk elsewhere, and, where possible, reducing flood
risk overall.
7.2.6
The NPPF advocates the use of the risk-based flood risk sequential test to steer new
development to areas at lowest probability of flooding. It also matches the flood risk
vulnerability of a development proposal to appropriate Flood Zones. For example, more
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sensitive developments, like hospitals, would not be permitted in areas at high risk of
flooding, although leisure and tourism developments may be allowed.
7.2.7
The NPPF provides details on how to include the potential effects of climate change on
development.
7.2.8
The government’s policies on conserving and enhancing the natural environment are
included in the NPPF, and guides local planning authorities and decision-takers on how
major new systems for pollution control and the management of contaminated land should
be taken into account when considering proposals for development.
7.2.9
The NPPF is accompanied by Technical Guidance which provides additional guidance to
ensure the effective implementation of the policy set out in the NPPF.
Adopted Dacorum Local Plan 1991-2011 (April 2004) and Dacorum Borough Council
Core Strategy (Modifications to the Pre-Submission Core Strategy 2013)
7.2.10
7.2.11
The relevant Local Plan policies are Policy 107: Development in Flood Risk Areas and Policy
124: Water Conservation and Sustainable Drainage Systems.

Policy 107 advocates that a precautionary approach to flood risk will be taken when
considering development based on the sequential approach set out in Planning Policy
Guidance Note 25 (subsequently superseded by Planning Policy Statement 25, and in
2012 by the NPPF).

Policy 124 is also relevant in that it highlights that applicants will be expected to
demonstrate that they have incorporated water conservation and sustainable drainage
practices into the design of their proposals.
The relevant Core Strategy policies are Policy CS31: Water Management and Policy CS32:
Air, Soil and Water.

Policy CS31 advocates retaining in the natural environment as far as possible and states
that measures to restore natural flows in the river systems and the water environment
will be supported and that supply to the Grand Union Canal should be maintained.

Policy CS32 states that “development will be required to help improve water quality
standards in line with the WFD, EA and Natural England Guidance.”
Building Regulations, 2010
7.2.12
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The Building Regulations Requirement H3 stipulates that rainwater from roofs and paved
areas is disposed of by, in order of priority: a soakaway or infiltration system; a nearby
watercourse; or a public sewer. The proposed surface water drainage strategy has taken
account of this order of priority.
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CIRIA C697, 2007
7.2.13
Sustainable Drainage System (SuDS) techniques as described in CIRIA C697 ‘The SuDS
Manual’ (CIRIA 2007) guidance aim to deal with surface water as close to the source as
possible and reproduce natural drainage patterns to prevent an increase in the volume and
peak discharge from development sites. CIRIA C697 provides developers with best practice
guidance on the planning, design, construction, operation and maintenance of SuDS.
‘Sewers for Adoption 7th Edition’, 2012
7.2.14
‘Sewers for Adoption 7th Edition’ provides guidance on the design, construction and
maintenance of drains and sewers outside buildings which are to be adopted by a relevant
public authority.
BS EN 752:2008 – ‘Drain and Sewer Systems Outside Buildings’, 2008
7.2.15
BS EN 752:2008 – ‘Drain and Sewer Systems Outside Buildings’ (2008), provides a
framework for the design, construction, rehabilitation, maintenance and operation of drain
and sewer systems outside buildings.
River Basin Management Plan, Thames River Basin District, 2009
7.2.16
The EA Thames River Basin Management Plan (TRBMP) focuses on achieving protection,
improvement and sustainable use of water and is a requirement of the WFD. The plan
identifies the management of future development as one of the key aspects which can
influence achievement of the WFD requirements.
Thames Catchment Flood Management Plan (CFMP)
7.2.17
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The EA Thames Catchment Flood Management Plan (TCFMP) is a high level strategic
planning document through which the EA will work with other stakeholders to identify and
agree policies for long-term flood risk over the next 50-100 years. It contains key messages
for the Thames region as a whole and more specifically for chalk tributaries to the River
Colne, including the River Gade. The key points with respect to the Colne catchment are
summarised below:

Safeguard the existing undeveloped natural floodplain through the appropriate
application of the sequential test;

Reduce the consequences of flooding through increasing public awareness of flooding;

Continue to reduce the impact of low frequency urban flooding (1 in 5 to 1 in 10 year
events) by maintaining conveyance where it is both effective and sustainable to do so,
and alleviating “pinch points” where possible;

Through urban areas, to naturalise the river where practicable; and
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
Gain a more complete understanding of surface water and drainage related flooding so
that any future improvements are part of a wider strategy for addressing these sources
of flooding.
Dacorum Strategic Flood Risk Assessment, 2007, 2008
7.2.18
DBC published its Level 1 Strategic Flood Risk Assessment (SFRA) in 2007 (DBC, 2007)
and its Level 2 SFRA in June 2008 (DBC, 2008).
7.2.19
The SFRA was carried out in close collaboration with officers of DBC and key stakeholders
such as the EA and Thames Water. The results allow the Local Authority to undertake the
Sequential and Exception Test required as part of the NPPF.
7.2.20
The SFRA makes a number of policy recommendations for new development summarised
below.

Achieve flood risk reduction through spatial planning and site design, including
application of the sequential test, flood resilient and resistant design, and ensure safe
access and egress;

Enhance and restore the river corridor, including setting back development from rivers
and raising bridge soffit levels;

Reduce surface runoff from new developments through the use of SuDS for new
developments, limiting runoff rates to Greenfield, and attenuating the 1 in 100 year
event;

Safeguard functional floodplain; and

Improve flood awareness and emergency planning.
Methodology
Baseline Data Collection
7.3.1
Details of the hydrology of the River Gade have been sourced from the DBC Level 2 SFRA
for Berkhamstead and Hemel Hempstead (DBC, 2008), the National River Flow Archive
(NRFA) and the Thames River Basin Management Plan (TRBMP).
7.3.2
The proposed development includes the diversion of 275m of the River Gade within the site
and the construction of a new crossing over the river. The potential impacts of the
realignment have been assessed by a WFD Assessment (AMEC, 2013) which is presented
in Appendix A.2.
7.3.3
Comprehensive river surveying has been undertaken as part of the WFD Assessment
providing a substantial body of baseline data for the River Gade within the site. The findings
are presented in Appendix A.2, and the detailed findings and baseline information from the
WFD assessment is summarised in this chapter.
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7.3.4
Information of the historical changes in the watercourse, including alignment and the
construction of the River Gade culvert, has been sourced from the SFRA and also on the
maps presented in Chapter 15 of this ES (Archaeology).
7.3.5
A review of historical flooding information in the vicinity of the site has been sourced from the
SFRA, the Environment Agency (EA), DBC, the British Hydrology Society (BHS) Chronology
of Flooding and through consultation with Thames Water and Hertfordshire County Council
(HCC).
7.3.6
Modelled fluvial flood outlines for the 1 in 100 year and 1 in 1000 year flood events have
been provided by the EA, from SFRA and from the hydraulic model of the River Gade
developed specifically for the SFRA (and provided to Weetwood by DBC).
7.3.7
No river gauging has been undertaken as part of the EIA process as sufficient information
was judged to be available from available sources.
7.3.8
Hydrogeological information for the site, including borehole data on underlying geology,
groundwater levels and water quality has been sourced from the Ground Investigation report
prepared by Applied Geology (Applied Geology, 2013), Appendix D.2. Information on
pumped abstraction by Affinity Water has been gained from the same source.
7.3.9
Information on hydrogeology has been sourced from an EA report on the Mid-Chilterns and
Colne Valley Chalk (Environmental Simulations International, 2005), the TRBMP (EA, 2009),
and the EA Catchment Abstraction Management Strategy for the River Colne (EA, 2007).
7.3.10
Details of the existing surface water drainage arrangements for the development site have
been sourced from the surface water drainage scheme developed by BSCP Ltd (see
Appendix B.5).
7.3.11
A detailed site specific Flood Risk Assessment (FRA) has been undertaken and the FRA
report accompanies the planning application.
7.3.12
The FRA report has been prepared in accordance with the requirements of the NPPF and
assesses the risk of flooding from a variety of potential sources including fluvial flooding from
the River Gade, from the failure of structures associated with reservoirs, canals and other
artificial structures, from groundwater emergence, and from surface water (pluvial, sewer
and highways). The assessment has been based on a detailed review of the information
provided in the sources listed as references and informed by consultation with relevant
stakeholders.
7.3.13
The FRA report presents a package of measures to mitigate on and off-site flood risk. The
mitigation measures have been informed by the previously referenced information sources
and consultees. The mitigation measures comply with the recommendations of the SFRA.
7.3.14
The key information presented in the FRA is presented in this chapter in sufficient detail to
enable this chapter to stand alone from the FRA report.
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Assessment
7.3.15
Surface and sub-surface receptors potentially susceptible to environmental impact from
flooding and drainage issues associated with the proposed development have been
identified. The identification of receptors has been informed by an assessment of baseline
conditions.
7.3.16
The ‘importance’ of each receptor has been designated using professional judgement and by
reference to the guidance criteria presented in Table 7.2.
7.3.17
The potential effects of the development on receptors have been identified using
professional experience guided by the baseline assessment, professional judgement and
stakeholder consultation.
7.3.18
Mitigation measures have been developed for each identified impact based on professional
experience and informed by best practices.
7.3.19
The magnitude of impacts following the application of the identified mitigation measures (i.e.
the residual impact) has been assessed with reference to the extent, magnitude and duration
of the effect and performance against environmental quality standards. See Table 7.3.
7.3.20
The significance of the residual (i.e. post mitigation) effects has been assessed based on the
importance of the receptor and the magnitude of the impact using the effect significance
matrix in Table 7.4.
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Table 7.2: Estimating Receptor Importance
Importance
Very High
Criteria
Receptor has a
high quality and
rarity on a
national or
regional scale
Measures
Surface Water:
 Designated Salmonid / Cyprinid fishery
 WFD Ecological status = High
 WFD Chemical status = Good
 Protected under EU or UK habitat legislation (e.g. Site of
Special Scientific Interest, EA Water Protection Zone, Ramsar
site)
Groundwater:
 Principal aquifer providing a regionally important resource or
supporting site protected under EU and UK habitat legislation
 Source Protection Zone 1
 WFD status = Good
Flood Risk:
 Flood Zone 3a and/or 3b
Surface Water:
 Major Cyprinid fishery
 WFD Ecological status = Good
 WFD Chemical status = Good
 Species protected under EU or UK habitat legislation
High
Receptor has a
high quality on a
local scale
Groundwater:
 Principal aquifer providing a locally important resource or
supporting river ecosystem
 Source Protection Zone 2
 WFD status = Good
Flood Risk:
 Flood Zone 2
Surface Water:
 WFD Ecological status = Moderate
 WFD Chemical status = Good
Medium
Receptor has a
medium quality
on a local scale
Groundwater:
 Secondary aquifer with limited connection to surface water
 WFD status = Good / Poor
 Source Protection Zone = 3
Flood Risk:
 Flood Zone = 2
Low
Receptor has a
low quality and
rarity on a local
scale
Surface Water:
 WFD Ecological status = Poor or Bad
 WFD Chemical status = Poor
Groundwater:
 Unproductive strata
 WFD status = Poor
Flood Risk:
 Flood Zone 1
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Table 7.3: Estimating the Magnitude of an Impact on a Receptor
Magnitude
Criteria
Descriptor
Surface Water:
 Reduction in WFD class
 High risk of pollution from a spillage
 Loss or extensive change to a fishery
 Loss or extensive change to a designated Nature Conservation
Site
Major
Adverse
Loss of receptor
or loss of
quality and /or
integrity of
receptor
Groundwater:
 Reduction in WFD class
 Loss of, or extensive change to an aquifer
 High risk of contamination of groundwater from polluted runoff
 Loss of, or extensive change to groundwater supported
wetlands
 Reduction in aquifer recharge
Flood Risk:
 100 year flood levels increased by at least 100 mm and/or
 Increase in flood risk due to potential blockage of new bridges or
other hydraulic structures
 Increase in extent of flood zones of > 3 ha
 Increase in properties at risk of flooding > 100
 Increase in people at risk of flooding > 100
Surface Water:
 Reduction in WFD class
 Medium risk of pollution from a spillage
 Partial loss of productivity of a fishery
Moderate
Adverse
Effect on
integrity of
receptor or loss
of part of
receptor
Groundwater:
 Reduction in WFD class
 Partial loss, or change to aquifer
 Medium risk of contamination of groundwater from polluted
runoff
 Partial loss of integrity of groundwater supported wetlands
Flood Risk:
 100 year flood levels increased by 50 - 100 mm
 Increase in flood risk due to potential blockage of new bridges or
other hydraulic structures
 Increase in extent of flood zones of 1 -3 ha
 Increase in properties in Flood Zone 2 and/or 3 of 25 -100
Surface Water:
 Minor risk of pollution from a spillage
Minor
Adverse
Negligible
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Measurable
change in
receptor quality
or vulnerability
Effect on
receptor but of
insufficient
magnitude to
affect the use or
integrity
Groundwater:
 Low risk of contamination of groundwater from polluted runoff
 Minor effects on groundwater supported wetlands
Flood Risk:
 100 year flood levels increased by less than 50 mm
 Increase in extent of flood zones of < 1 ha
 Increase in properties in Flood Zone 2 and/or 3 of 5-25
Surface Water:
 Negligible or no of pollution from a spillage
Groundwater:
 No measurable impact on aquifer
 Negligible risk of pollution from spillages
Flood Risk:
 Negligible change in flood levels (less than +/- 25 mm)
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Magnitude
Criteria
Descriptor


No change in extent of flood zones
Change in number of properties in Flood Zone 2 and/or 3 of <5
Surface Water:
 Improvement in WFD class
Minor
Beneficial
Some beneficial
effect on
receptor or a
reduced risk of
negative effect
occurring
Groundwater:
 Significant reduction in risk of pollution of groundwater by
spillage
Flood Risk:
 100 year flood levels reduced by less than 50 mm
 Reduction in extent of flood zones of < 1 ha
 Reduction in properties in Flood Zone 2 and/or 3 of 5-25
Surface Water:
 Improvement in WFD class
Moderate
Beneficial
Moderate
improvement of
receptor quality
Groundwater:
 Improvement in WFD class
 Major reduction in risk of pollution of groundwater by spillage
Flood Risk:
 100 year flood levels reduced by 50 - 100 mm
 Reduction in extent of flood zones of 1 - 3 ha
 Reduction in properties in Flood Zone 2 and/or 3 of 25-100
Surface Water:
 Improvement in WFD class
 Removal of existing polluting discharge to or removal of
likelihood of polluting discharge occurring
Major
Beneficial
Major
improvement in
receptor quality
Groundwater:
 Improvement in WFD class
 Removal of existing polluting discharge to aquifer or removal of
likelihood of polluting discharge occurring
 Increase in aquifer recharge
Flood Risk:
 100 year flood levels reduced by more than 100 mm
 Reduction in extent of flood zones of > 3 ha
 Reduction in properties in Flood Zone 2 and/or 3 >100
Table 7.4: Estimating the Significance of Potential Effects
Magnitude of Impact
Importance of
Receptor
Negligible
Small
Medium
Large
Very high
Not Significant
Minor/Moderate
Major
Severe
High
Not Significant
Minor
Moderate
Major
Medium
Not Significant
Not Significant
Minor
Moderate
Low
Not Significant
Not Significant
Not Significant
Minor
Baseline Conditions
River Gade Receptor
7.4.1
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The following section refers to a number of figures presented in Appendix B.1. The course
of the River Gade through the existing site is presented in Figure 7.1 and the location of the
boreholes used during the site investigation works are indicated on Figure 7.6.
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Hydrology
7.4.2
The River Gade rises on the dip slope of the Chiltern Hills near Great Gaddesden and flows
in a southerly direction through Hemel Hempstead before discharging into the Grand Union
Canal at NGR TL055060. Much of the flow then spills via a weir at NGR TL056059 and
flows south towards its confluence with the River Bulbourne at Two Waters (NGR
TL056057).
7.4.3
Between here and its confluence with the River Colne at Rickmansworth (NGR TQ072943),
the River Gade follows the Grand Union Canal through Apsley, King’s Langley and Croxley,
sometimes in a combined channel and sometimes separate from the canal.
7.4.4
The upper reaches of the River Gade form an ephemeral chalk stream rising from springs
near Hudnall Corner (at NGR TL012139). Above Great Gaddesden the watercourse is dry
throughout the summer months and only flows during winter periods.
7.4.5
Below Great Gaddesden flows increase gradually from spring seepages, treated sewage at
Great Gaddesden and surface water runoff.
7.4.6
The river in its natural state would exist as a small and shallow gravel-bed channel for most
of its length; however, it has been modified historically by installation of numerous weirs to
provide power for mills, by hard bank construction for amenity purposes in Hemel
Hempstead and by flood alleviation measures. The Gade catchment is part of the River
Colne catchment unit which drains into the River Thames at Staines.
7.4.7
The underlying geology is chalk, with some tertiary deposits and extensive boulder clay. As
a result the catchment is relatively permeable. The natural response of the river is relatively
slow with characteristically low peaks. Superimposed on this damped baseflow component
is a faster direct runoff component (particularly from urban areas).
7.4.8
Streams such as the River Gade that rise on chalk in southern England share a number of
hydrogeological, hydrological and ecological characteristics that, combined, define a river
type known as a ‘chalk stream’ or ‘chalk bourne’. Chalk streams were recognised as a
priority habitat in the UK Biodiversity Action Plan, developed to implement the Rio
Convention, and protection has been carried forward in the definition of rivers as a habitat of
principal importance under s.41 of the Natural Environment and Rural Communities Act
2006. Chalk streams of the Chilterns are recognised as part of the ‘rivers’ habitat defined
under s.41 of this Act.
7.4.9
The River Gade is gauged at the former site of Bury Mill upstream of the site (Station
Number 39089, Gade at Hemel Hempstead, NGR TL 053076) approximately 200m north of
the northern boundary of the site.
7.4.10
According to the National River Flow Archive (NRFA) gauging station information sheet
(provided in Appendix B.2) the catchment area to the gauging station is approximately
48.2km2. Continuous records of the station exist since 1975 and the mean flow over this
period is 0.16 m 3/s. The highest recorded flow of 1.2m 3/s was observed on 5 July 1983. It is
not known whether the 1983 peak was exceeded since 2011.
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7.4.11
The NRFA states that: the catchment is predominantly rural (overall urban extent of 3%) and
predominantly permeable, consisting of chalk but with some boulder clay cover. The
catchment has a baseflow index (BFI) of 0.92 indicating that a large proportion of the river
flow is from stored sources.
7.4.12
The findings of a river habitat survey of the River Gade through the site is presented in the
WFD Assessment and summarised below:
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
Generally natural with small reinforced sections of bank.

The left and right banks are reasonably natural and consist entirely of earth.

Two vegetated side bars were recorded along the left bank and three along the right
bank. A single vegetated mid-channel bar and unvegetated silt deposits were also
present.

The channel substrate comprises gravel / pebble but silt was also present.

The flow was mostly rippled or smooth with the occasional riffle.

The bank profile is asymmetrical with the left bank top height measuring approximately
1.5m compared to 0.75m for the right, mainly with a gentle slope but with some sections
of vertical and undercut bank.

The bank full width is 3m and the water width 1m, with an average depth of 0.2m.

The majority of the surrounding land comprises grassland which is managed via
mowing/trimming.

The channel is generally devoid of in-channel vegetation but a few emergent broadleaved herbs and emergent reeds are present in the upstream section.

The left bank supports occasional clumps of trees whilst the tree cover on the right hand
side is semi-continuous.

Part of the channel is shaded by overhanging boughs and there are underwater tree
roots.

When associated with minor bridge crossings, the whole of the bank profile is reinforced
with concrete.

The bank at the end of the reach is reinforced at the toe with wooden piling.

The reach contained abundant signal crayfish and stickleback.

No invasive plant species were recorded.
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Water Body Modifications
7.4.13
The River Gade has been extensively modified through Hemel Hempstead from the mid
1700’s (estimated date) on. The historical context, together with mapping, is presented in
Chapter 15 of this ES and the key changes with respect to channel alignment modifications
are summarised below. The current river alignment in the vicinity of the site is shown on
Figure 7.1, Appendix B.1.
7.4.14
The earliest available OS map, dated 1766, indicates the river running through the centre of
what is now Gadebridge Park in a southerly direction through the site. The map indicates a
mill race to the west of the natural channel, formed by diverting flows from the main channel
to the north. The channels appear to rejoin further south at a location close to or within the
site.
7.4.15
A tithe map dated 1843 again shows a diverted channel serving Bury Mill with the original
river channel continuing to flow through the centre of Gadebridge Park. The mill race feeds
a mill pond and an overflow channel has been constructed following an east-west alignment
to its confluence with the original watercourse to the east. The original watercourse
converges with the diverted ‘mill channel’ south of the mill. Both channels appear to run on
parallel but separate courses, although this is not clear from the mapping. The situation
described appears to have existed until the late 1950’s.
7.4.16
In circa 1959, the western ‘mill channel’ main channel was culverted to facilitate construction
of the Leighton Buzzard relief road. This culvert is referred to variously as the Hemel
Hempstead flood relief culvert (SFRA) and the flood relief culvert (Gade Zone Planning
Statement). However, in this chapter it is referred to as the River Gade culvert since a
significant proportion of the River Gade flow passes through it, even in relatively low flow
conditions.
7.4.17
The inlet to the River Gade culvert is immediately upstream (north) of Queensway. At this
point, the mill channel bifurcates, with part following an easterly course (as per the former
mill pond overflow) before turning south under Queensway (low single span culvert) and
through the site, and part continuing on a southerly course through the River Gade culvert.
The natural watercourse through the centre of Gadebridge Park is no longer shown on
mapping and current records indicate that it runs in a culvert through the park before
outfalling almost directly into the River Gade culvert.
7.4.18
The amount of flow diverted from the above ground mill channel into the River Gade culvert
is controlled by an adjustable weir upstream of the culvert inlet. Raising the height of the
weir crest by inserted timber boards will reduce the amount of water diverted into the River
Gade culvert and increase the flow in the above ground reach of the river through the site
and further south.
7.4.19
The River Gade culvert is understood to receive surface water runoff at a number of
locations as it passes through the site and further south, although the details of these inflows
are not known.
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7.4.20
The River Gade culvert is owned by Thames Water. It is approximately 2m x 2m and is
believed to run 5 m below ground level (to invert). The conveyance capacity is estimated to
be 9.4 m3/s based on an assumed gradient of 0.004 and a Mannings n of 0.017. This is
approximately 8 times greater than the largest recorded flow and 60 times greater than the
mean flow.
7.4.21
The culvert significantly reduces flood risk further south (i.e. in Hemel Hempstead) and it is
often referred to as the Hemel Hempstead flood relief culvert in the literature, including in the
Dacorum SFRA.
7.4.22
The open channel of the River Gade downstream of Queensway was realigned in the 1960’s
to accommodate the construction of the college in the 1960s by HCC and again when the
section of the Town Hall west of Dacorum Way was constructed.
7.4.23
Downstream of the development site the river channel from Combe Street to Moor End Road
was straightened and widened in the later 1950’s and a number of approximately 0.5m high
weirs were constructed allowing the formation of a series of ponds to form Hemel
Hempstead Water Gardens, as part of the development of Hemel Hempstead as a new
town. The channel banks are mainly concrete and the river bed is silty. The Water Gardens
are listed (Grade II) on the Register of Parks and Gardens of Special Historic Interest.
7.4.24
In about 2005, the River Gade between Moor End Road and south of the A4146 roundabout
was deculverted, realigned and ‘naturalised’ as part of the Riverside Shopping Centre
development. The creation of a two-stage channel has resulted in a relatively narrow but
fast flowing low-flow channel, a gravel bed and a varied flow regime (runs and pools). The
wider, high-flow channel has allowed for marginal planting and provides additional channel
capacity during high flows.
7.4.25
The River Gade culvert follows a north-south alignment past Hemel Hempstead and Apsley
before rejoining the above open River Gade channel via a lake at Kings Park Industrial
Estate in Kings Langley (NGR TL073038). This has not been verified by a site visit.
7.4.26
The River Gade from Hudnall to the Grand Union Canal is a designated Main River and the
EA has discretionary powers within the Water Resources Act 1991 to carry out works to the
river for which access must be maintained. The Land Drainage Byelaws require the prior
written consent of the EA for ‘Works Affecting Watercourses’ for any proposed works or
structures in, over, under or within a distance of 8 metres from the top of the banks of the
River.
7.4.27
The river bed from Gadebridge Park through to the Grand Union Canal is owned by DBC
which has a responsibility to maintain the river.
7.4.28
A number of initiatives for restoration of Chiltern chalk streams, including the River Gade, are
currently being pursued through the Dacorum Environmental Forum Water Group, which is
supported by DBC, the EA, Affinity Water and local stakeholder groups. The group has
developed the Dacorum Chalk River Restoration Strategy. The Chiltern Conservation Board
also leads the Chilterns Chalk Streams Project, in partnership with the Chiltern Society,
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Chiltern District Council, DBC, Buckinghamshire County Council, Affinity Water, Thames
Water, EA, The Wildlife Trusts and the Countryside Management Service.
Water Quality
7.4.29
In 2009 the EA adopted the EU WFD classification of water quality. The WFD Classification
is based on over 30 measures and uses a “one out, all out” methodology whereby the
poorest individual result drives the overall result (Environment Agency, 2011).
7.4.30
For surface waters there are two separate classifications for water bodies: ecological and
chemical. For a water body to be in overall good status both ecological and chemical status
must be at least good.
7.4.31
Ecological classification comprises: the condition of biological elements (e.g. fish
populations); concentrations of supporting physico-chemical elements (e.g. oxygen or
ammonia levels); concentrations of specific pollutants (e.g. copper) and hydro-morphological
quality (i.e. hydrology and morphology).
7.4.32
Ecological status is recorded on the scale of high, good, moderate, poor or bad. High
denotes largely undisturbed conditions and the other classes represent increasing deviation
from this natural (reference) condition. The ecological status classification for the water body
and the confidence in this is determined using the worst scoring quality element.
7.4.33
Chemical status is assessed by compliance with environmental standards for chemicals that
are listed in the Environmental Quality Standards Directive 2008/105/EC. These chemicals
include priority substances, priority hazardous substances and eight other pollutants carried
over from the Dangerous Substance Daughter Directives. Chemical status is recorded as
good or fail and is determined by the worst scoring chemical.
7.4.34
The reach of the River Gade that passes through the site has a WFD reference of “Gade
Upper Stretch Great Gaddesden to confluence with Bulbourne / GUC” (GB106039029900).
The water body is approximately 11 km in length.
7.4.35
Details of the current status of the water body as included in the TRBMP are presented in
Appendix B.3. Key parameters are summarised below:
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
The River Gade is identified as being “not assigned as a Heavily Modified Water Body or
Artificial Water Body.”

The water body has an overall moderate ecological status and a target of good
ecological status by 2015 has been set.

In terms of biological elements (fish and invertebrates) the water body has moderate
status.

From the results of ongoing data collection, the EA has confirmed that the site at Water
End meets the requirements for high status in 2012.
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
The overall physio-chemical status is moderate.
dissolved oxygen which is bad.

The overall hydromorphology status is not high. Hydrology is classified as moderate and
morphology as good.

Chemical status does not require assessment because priority substances and other
specific pollutants are not discharged into the water body in significant quantities.
All measures are high except for
7.4.36
The River Gade is designated as a salmonid water under the EC Freshwater Fish Directive.
This means that the water body is classed as a protected area under Article 6 of the WFD
and must comply with any additional standards, in this case relating to controls on
agricultural practice.
7.4.37
The development site is within a nitrate vulnerable zone as defined under the EC Nitrates
Directive, i.e. is in an areas that drains into nitrate polluted waters, or waters which could
become polluted by nitrates. However, the controls relate principally to a reduction in the
use of agricultural fertilisers and as such are not relevant to the proposed development.
7.4.38
Water quality data are presented in detail in the WFD Assessment Appendix A.2:
7.4.39
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
Water quality a short distance upstream of the development site shows no failures to
comply with environmental quality standards set by the WFD Directions (see Table 2.2
of the WFD Assessment Appendix A.2), taking account of the river typology applicable
to the River Gade.

In terms of the Surface Waters (Fishlife) Directions, the river fails to comply in relation to
oxygen demand (BOD5atu), marginally at Water End and for nitrites.

For ammoniacal nitrogen, the detection limit (30μg/l as nitrogen) was almost the same as
the 31μg/l 95%ile standard set by the Surface Waters (Fishlife) Directions so the
apparent exceedence of this standard cannot be regarded as conclusive.
With regards the site, a drainage investigation has been carried out by a specialist drainage
contractor to establish the connectivity and outfalls of the existing surface and foul drainage
systems. The investigations have identified the following:

Surface water from the existing buildings and hardstandings drains into the River Gade
culvert via a number of separate individual surface water drainage systems.

No surface water outfalls into the open channel reach of the River Gade as it passes
through the site were identified.

There are no attenuation tanks or fuel interceptors in the existing surface water drainage
systems. Consequently surface water runoff discharges at an uncontrolled rate to the
River Gade culvert and may be contaminated with pollutants, particularly during the “first
flush” following a dry period. The effect of any contaminant loading from this source may
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impact on the water quality of downstream water bodies including the River Gade, Grand
Union Canal and River Bulbourne.
Catchment Abstractions
7.4.40
According to the Envirocheck report (refer Appendix D.2) there is a surface water
abstraction approximately 290 m north-west of the site operated by DBC for spray irrigation.
7.4.41
The abstractions in the catchment further upstream are nearly all groundwater abstractions
and little of the groundwater abstracted for public water supply re-enters the catchment, most
sewage flowing to Maple Lodge sewage works near Rickmansworth, with treated effluent
discharged into the River Colne.
7.4.42
The Upper Gade was identified in the EA Restoring Sustainable River Abstraction
Programme (RSAP) and Colne Catchment Abstraction Management Strategy as a
catchment which suffers from over abstraction. In order to improve flows in the river under
drought conditions a number of options were identified in a Sustainability Report
commissioned by the EA. These options included weir modification and channel re-profiling
works in order to achieve an improved hydrological regime at times of low flow.
7.4.43
Subsequently, Three Valleys Water commissioned an audit of the 29 weirs identified on the
river between its source and the confluence with the Grand Union Canal south of Hemel
Hempstead. The study assessed the size, location and operation of the weirs and collected
macroinvertebrate samples at two sites upstream of Hemel Hempstead town centre. The
report recommended channel narrowing, to create more natural meanders, as well as
removal of a number of weirs, planting of marginal vegetation, the prevention of trampling by
cattle and the removal of invasive alien species. This would facilitate faster flowing water
and the development of a gravel bed typical of chalk streams.
7.4.44
For the urban reach, either the recreation of a separate river channel or the removal of the
large concrete weir structure and narrowing of the current channel were recommended to
create a more dynamic river environment replacing the existing slow flowing sections and
allow fish movement along the whole of this section.
Flood Risk
7.4.45
There is a history of recent flooding of Gadebridge Park upstream, most recently in March
2007 and November 2012. The extent of flooding of the park can be extensive and the flood
water can take some time to disperse due to the perched nature of the current channel.
7.4.46
There are no records of fluvial flooding further downstream in Hemel Hempstead or of the
site in the BHS Chronology of Flooding and no flooding of the site has occurred in recent
years.
7.4.47
The SFRA details that major fluvial flooding events occurred in the River Gade and River
Bulbourne catchments during 1879 and 1947 but states that “the flood events occurred
before the Hemel Hempstead flood relief scheme (i.e. the River Gade culvert) was
constructed in 1959. This offers significant protection to Hemel Hempstead to beyond a 100
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year standard of protection as well as some protection to Apsley and Kings Langley. Since
this became operational no further fluvial flooding has occurred in these areas.”
7.4.48
According to the EA flood map (Figure 7.2, Appendix B.1) the site is located in Flood Zones
1, 2 and 3. Table 1 of the NPPF Technical Guidance (Department of Communities and
Local Government, 2012b) provides the following flood zone definitions.

Flood Zone 1: Low Probability. Land assessed as having a less than 1 in 1000 annual
probability of river or flooding from the sea in any year (<0.1%).

Flood Zone 2: Medium Probability. Land assessed as having between a 1 in 100 and 1
in 1000 annual probability of river flooding (1% - 0.1%) or between a 1 in 200 and 1 in
1000 annual probability of flooding from the sea (0.5% - 0.1%) in any year.

Flood Zone 3a: High Probability. Land assessed as having a 1 in 100 or greater annual
probability of river flooding (>1%) or a 1 in 200 or greater annual probability of flooding
from the sea (>1%) in any year.

Flood Zone 3b: The Functional Floodplain. Land where water has to flow or be stored in
times of flood. The identification of the functional floodplain should take account of local
circumstance and not be defined solely on rigid probability parameters. However, land
which would flood with an annual probability of 1 in 20 or greater in any year should
provide a starting point for consideration and discussion.
7.4.49
The EA flood map does not take into account the presence of the River Gade culvert and
maps the extent of flooding that would occur should all flows in the river Gade be routed
along the above ground reach of the River Gade through the site. In reality, a significant
proportion of river flow passes through the River Gade culvert. Consequently, the EA flood
map significantly overstates flood risk on the site.
7.4.50
Appendix D of the SFRA presents a flood map based on hydraulic modelling specifically
undertaken for the SFRA (see Figure 7.3, Appendix B.1). The modelling includes the River
Gade culvert although the flood outlines presented on the flood map assume that the River
Gade culvert is 75% blocked. The SFRA flood outlines, although still conservative, indicate
that a smaller extent of the site is located within the 1 in 100 year flood outline (Flood Zone
3) than indicated by the EA flood map. The SFRA flood map also indicates that part of the
site is located within the 1 in 20 year flood outline (Flood Zone 3b - functional floodplain).
7.4.51
A more accurate flood map for the existing site layout has been prepared as part of the site
specific Flood Risk Assessment using modelled levels from the SFRA hydraulic model
superimposed on site levels provided by a topographic survey. It is presented in Figure 7.4,
Appendix B.1.
7.4.52
A building of the existing college is located in Flood Zone 3, a footprint of approximately 323
m2. Demolition of this building would increase flood storage on this part of the site, although
it is not possible to quantify this gain in volumetric terms until the final ground levels are
known.
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7.4.53
No incidences of highways flooding are recorded on HCC’s online fault reporting and
recording system1. The council holds a record of flooding of Leighton Buzzard Road on 22
December 20122 as follows: “Flooding deep enough to force traffic onto the west side of
Leighton Buzzard Road, covering most of carriageway for approx 9 metres. Happens after
rain and takes about 6 hours to dissipate afterwards” which appears to be due to the
highways drainage being overwhelmed by extended and heavy rainfall. Further information3
has identified that the flooding was north of the site and to the west of Gadebridge Park near
the junction with the A4147.
7.4.54
The SFRA indicates minor surface water flooding has occurred to the south of the site in the
vicinity of the Central Library in Combe Street. However, no further details are provided
regarding the cause, extent or regularity of flooding.
7.4.55
As previously stated, there are no attenuation tanks in the existing site surface water
drainage systems. Consequently surface water runoff discharges at an uncontrolled rate to
the River Gade culvert. Current drainage standards seek to prevent the uncontrolled release
of surface water to minimise the likelihood of development increasing flood risk downstream
due to fast runoff from impermeable surfaces.
Aquifer Receptor
Hydrogeology and Ground Conditions
7.4.56
The EA uses aquifer designations consistent with the EU WFD and EA Groundwater
Protection Policy. These reflect the importance of aquifers in terms of groundwater as a
resource for drinking water and its role in supporting rivers, lakes and wetland ecosystems.
7.4.57
The aquifer designation is in two categories - superficial (drift) and bedrock, and aquifers are
then classified according to whether they are principal or secondary.
7.4.58
Principal aquifers have high inter-granular and/or fracture permeability and may provide a
high level of water storage and support water supply and/or river baseflow on a strategic
scale. Secondary aquifers include a wide range of rock layers or drift deposits with an
equally wide range of water permeability and storage. Secondary aquifers are subdivided
into two types:

Secondary A - permeable layers capable of supporting water supplies at a local rather
than strategic scale, and in some cases forming an important source of baseflow to
rivers.

Secondary B - predominantly lower permeability layers which may foodstore and yield
limited amounts of groundwater due to localised features such as fissures, thin
permeable horizons and weathering. These are generally the water-bearing parts of the
former non-aquifers.
1
Available at http://www.hertsdirect.org/faultsearch/
Telephone conversation with Claire Green (HCC Highways Dept) on 19 April 2013
3 http://www.fixmystreet.com/reports/Hertfordshire/Hemel+Hempstead+Town
2
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7.4.59
Reference to British Geological Survey (BGS) Sheet ‘238’ drift edition indicates the site to be
underlain by Alluvium overlying Middle Chalk strata comprising the White Chalk Sub-group.
The Alluvium is indicated to be locally underlain by River Terrace Gravel in the vicinity of the
site.
7.4.60
According to the EA Groundwater Vulnerability Map the site is underlain by a principal
bedrock aquifer overlain by a secondary aquifer (Figure 7.5, Appendix B.1).
7.4.61
The Colne Catchment Abstraction Strategy states the chalk in this region to be the most
significant aquifer in southern England and of regional and national significance in terms of
abstracted volume and development for abstraction.
7.4.62
The ground conditions at the site have been determined from seventeen exploratory
boreholes, twelve driven continuous sampling boreholes to depths of between 1.10m and
5.45m bgl and five cable percussion boreholes to depths of between 20.0m and 35.0m bgl.
The locations of the boreholes are shown on Figure 7.6, Appendix B.1.
7.4.63
The site investigations are described fully in Chapter 9, Ground Conditions and supporting
appendices.
7.4.64
A conceptual model of ground conditions is presented in Appendix D.1.
Groundwater Quality
7.4.65
According to the TRBMP, the Mid Chilterns Chalk groundwater body (reference
GB40601G01200) underlying the site is assessed to have a poor overall status,
7.4.66
The achievement of good status in groundwater involves meeting a series of conditions
which are defined in the WFD (2000/60/EC) and Groundwater Directive (2006/118/EC). In
order to assess whether these conditions are being met, a series of tests have been
designed for each of the quality elements defining good (chemical and quantitative)
groundwater status.
7.4.67
There are five chemical and four quantitative tests, the latter being an expression of the
degree to which a body of groundwater is affected by direct and indirect abstractions. Each
test is applied independently and the results combined to give an overall assessment of
groundwater body chemical and quantitative status. The worst case classification from the
relevant chemical status tests is reported as the overall chemical status for the groundwater
body and the worst case classification of the quantitative tests reported as the overall
quantitative status for the groundwater body. The worst result of these two is reported as the
overall groundwater body status. Groundwater is classed as having good or poor status.
7.4.68
At present, the water body overall has poor status based on both its quantitative and its
qualitative status. In terms of quantity, it is rated as poor with regard to its impact on surface
water flows and poor in relation to water balance (i.e. it is considered over-abstracted). In
terms of quality, it is rated poor based on compliance with standards applicable for a drinking
water protected area for ammonia, nitrate, copper, nickel and various pesticides.
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7.4.69
According to the TRBMP the main pressures facing the aquifer are due to hazardous
substances and other pollutants from point sources and pesticides, and from high nitrate
levels.
7.4.70
Detailed information on groundwater quality has been obtained through the site
investigations undertaken in 2012/13 and described in Chapter 9, Ground Conditions. The
key findings are summarised below.
7.4.71
Five groundwater samples were collected and tested as part of the ground investigations
undertaken in 2010 by RSK (see in Chapter 9, Ground Conditions). The testing identified
all but one of the determinants tested for to be below the UK Drinking Water Standards
(DWS). The elevated determinant was Total Petroleum Hydrocarbons (TPH), however, the
two elevated results were noted as being marginal and not considered to pose a risk to
groundwater receptors.
7.4.72
A Level 2 assessment of data was undertaken in 2012/13 as part of the ground investigation
presented in Chapter 9 in which water quality data from samples taken from a number of
standpipes across the site were compared to the UK DWS.
7.4.73
The results indicate the majority of determinant concentrations to be below the analysis
specific detection limits and in all cases well below the UK DWS.
7.4.74
The findings indicate that the groundwater below the site has not been impacted by any
contamination sources within the site or off-site and therefore the site is currently considered
unlikely to pose a significant risk to groundwater.
Groundwater Abstractions
7.4.75
The site is located in Source Protection Zone 1 (SPZ 1) for the public water supply boreholes
located as indicated by the EA Groundwater Vulnerability Map (see Figure 7.7, Appendix
B.1).
7.4.76
SPZs are designated to protect groundwater sources used for public drinking water supply
against the transmission of toxic chemicals and water-borne disease, establish pollution
prevention measures and monitor the activities of potential polluters. SPZ1, the inner
protection zone, is defined as the area from where pollution can travel to the groundwater
source within 50 days or within a 50m radius.
7.4.77
According to the Envirocheck report (see Appendix D.2), Affinity Water operate two licences
for groundwater abstractions for public water supply on-site and a further licence at Piccotts
End approximately 1.7km north of the site. These abstractions are shown on Figure 7.7.
7.4.78
There are no other groundwater abstractions on the development site and no other
substantial groundwater abstractions in the vicinity of the site.
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Groundwater Levels
7.4.79
Detailed information on groundwater levels has been obtained through the site investigations
undertaken in 2012/13 and described in Chapter 9. The key findings are summarised
below.
7.4.80
Groundwater was encountered in four of twelve shallow boreholes at depths of between
2.60m and 3.70m bgl. The groundwater ingress was typically associated with the Alluvium
as seepages and occasionally as occasionally as standing water.
7.4.81
Groundwater was encountered within two of the five deeper boreholes during drilling at
depths of between 4.80m and 13.50m bgl, rising after twenty minutes to depths of 4.10m and
9.50m bgl respectively. Subsequent monitoring indicated standing water levels of between
2.76m and 3.45m bgl in four of shallow boreholes with the other installations remaining dry
during all four monitoring visits.
7.4.82
The levels of groundwater indicate an overall southerly groundwater flow.
7.4.83
Groundwater levels within the principal chalk aquifer monitored at three deep boreholes for
the period 8 November 2012 to 21 February 2013 are presented in Appendix D.2. The key
observations are summarised below:

At CPBH1 (the borehole closest to the pumping station) water levels ranged between
3.85m bgl (deepest) to 2.30m bgl (shallowest).

At CPBH3 (the borehole furthest away from the pumping station) water levels ranged
between 2.42m (deepest) and 1.07m (shallowest) with the shallowest levels observed
between 22 December 2012 and 14 January 2013 when Affinity Water temporarily
ceased pumping.
7.4.84
The data indicates that the River Gade was not in hydraulic continuity with the shallow
aquifer during the monitoring period.
7.4.85
The data generally shows an overall rise in the groundwater level over the three month
period, possibly due to an exceptionally wet period preceding and during the monitoring
period.
7.4.86
A periodic variation in groundwater levels of 12 hours is observed in all three deep boreholes
– a sharp fall in level followed by a gradual rise or rebound back to slightly less than the
original level. Discussions with Affinity Water have confirmed this to be linked to Affinity
Water’s pumping regime at the site.
7.4.87
The British Geological Survey (BGS) susceptibility to groundwater flooding map (Figure 7.8,
Appendix B.1) indicates that a corridor approximately 500 m wide along the course of the
River Gade through Hemel Hempstead is at moderate to significant risk of flooding from
groundwater. However, there are no records of groundwater flooding in Hemel Hempstead
or of the site in the BHS Chronology of Flooding and the monitored groundwater levels
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confirm that groundwater flooding of the site would not be expected if the observed
groundwater levels are maintained.
Importance of Development Receptors
7.4.88
Table 7.5 lists the identified receptors and their importance/scale as assessed using as
guidance the criteria presented in Table 7.2. Where no quantitative information on water
quality exists a subjective assessment of importance has been made.
7.4.89
The rationale for the importance categorisations are discussed below:
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
River Gade – The 11km reach of the River Gade that passes through the site has
moderate overall WFD ecological status and a target for 2015 of good. Biological and
physio-chemical status are both assessed as moderate (although for the latter, all
measures are high except for dissolved oxygen which is bad), hydrology is classified as
moderate and morphology as good. The River Gade is a designated salmonid water
and chalk stream. For these reasons, the River Gade receptor is assessed to have high
importance.

Aquifer – The site is underlain by strategically important superficial and bedrock aquifers
providing high quality water for public supply locally and regionally. Groundwater also
contributes a major component of flow in the River Gade upstream of the site. For this
reason the aquifer is assessed to have a very high importance.

Site workers (flood risk) – The River Gade passes through the site and is a potential
source of fluvial flooding. Actual flood risk at the site is assessed to be low due to the
presence of the River Gade culvert which is not taken into account by the EA flood map.
However, there is a residual risk associated with potential blockage of the River Gade
culvert And for this reason this receptor is considered to have high importance.

Users of “The Link” (flood risk) – The previous comments relating to flood risk apply to
this receptor which is considered to have high importance.

Surrounding users/occupiers (flood risk) – The previous comments relating to flood risk
apply to this receptor which is considered to have high importance.
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Table 7.5: Development Receptors
Receptor
Importance
River Gade
(Water quality i.e. biological and physico-chemical quality, hydrology,
hydromorphology)
High
Aquifer
(Water quality)
Very High
Site workers
(Flood risk) – Construction Phase only
High
Users of “The Link”
(Flood risk) – Operational Phase only
High
Surrounding users/occupiers
(Flood risk)
High
Potential Environmental Effects
Construction Phase
River Gade Receptor
7.5.1
The temporary construction works at or in the close vicinity to the River Gade could reduce
the channel conveyance capacity due to temporary blockage(s) potentially increasing flood
risk. This direct, adverse impact would be temporary and of short duration. (Flood Risk)
7.5.2
A large number of construction workers will be on site, increasing overall flood risk. This
adverse effect would be temporary and of short duration. (Flood Risk)
7.5.3
Mobilised ground contaminants and/or sediments during temporary works could enter and
pollute River Gade main channel via overland flow or the River Gade culvert via the surface
water drainage system. This adverse effect would be temporary and of short duration.
(Water Quality)
7.5.4
Spilled contaminants could enter and pollute the River Gade main channel via overland flow
or the River Gade culvert via the surface water drainage system. This adverse effect would
be temporary and of short duration. (Water Quality)
7.5.5
The development will require the divesting and diversion of existing foul sewers. There is a
risk of pollution to the River Gade whilst these works are undertaken. This direct, adverse
impact would be temporary and of short duration (i.e. less than 12 months).
7.5.6
The structural integrity of the River Gade culvert is at risk from the construction works. Any
blockage of the culvert would restrict the conveyance capacity of the culvert thereby
increasing flood risk on-site and further downstream. This direct, adverse impact would be
temporary. The duration of the effect would depend on how long it took to repair the
damage. (Flood Risk)
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7.5.7
Realignment of the River Gade channel may impact on the channel conveyance capacity
during the re-alignment works. This direct, adverse impact would be temporary and of short
duration. (Flood Risk)
Aquifer Receptor
7.5.8
Mobilised ground contaminants and/or sediments during temporary works could enter and
pollute the shallow aquifer by infiltration resulting in groundwater contamination. This
adverse effect would be temporary and of short duration. (Water Quality)
7.5.9
Spilled contaminants could enter and pollute the shallow aquifer by infiltration resulting in the
groundwater contamination. This adverse effect would be temporary and of short duration.
(Water Quality)
7.5.10
The structural integrity of a main foul sewer through the site is at risk from the construction
works. Any rupture of the sewer could result in the contamination of the shallow aquifer.
This direct, adverse impact would be temporary. The duration of the effect would depend on
how long it took to repair the damage. (Water Quality)
7.5.11
New pathways for the migration of surface contaminants into the underlying aquifer by
infiltration may be created due to piling activities and/or ground excavation resulting in the
groundwater contamination. This adverse effect would be temporary and of short duration.
(Water Quality)
7.5.12
The development will require the divesting and diversion of existing foul sewers. There is a
risk of pollution to the aquifer whilst these works are undertaken. This direct, adverse impact
would be temporary and of short duration. (Water Quality)
Site Workers Receptor
7.5.13
There will be a large number of construction workers on site which will increase the overall
level of flood risk. (Flood Risk)
Surrounding Users / Occupiers
7.5.14
The construction works may increase the risk of off-site flooding. (Flood Risk)
Operational Phase
River Gade Receptor
7.5.15
The impermeable area of the site will increase as a result of the proposed development. The
increase in peak surface water runoff rates and the total runoff volumes would increase flood
risk downstream. This direct, adverse effect would be permanent. (Flood Risk)
7.5.16
The new road bridge and/or pedestrian bridge could reduce the conveyance capacity of the
River Gade due to the soffit level being too low and/or having an insufficient width, thereby
increasing flood risk. This direct, adverse effect would be permanent. (Flood Risk)
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7.5.17
The conveyance capacity of the new road bridge and/or pedestrian bridge could reduce the
conveyance capacity of the River Gade at times of flood due to blockage from debris. This
direct, adverse effect would be temporary and of short duration. (Flood Risk)
7.5.18
The realignment of the River Gade may reduce the channel conveyance capacity resulting in
an increase in flood risk through the site. This direct, adverse effect will be permanent.
(Flood Risk)
7.5.19
The increase in impermeable area, in traffic volumes and activity, the petrol filling station
(PFS), car wash and the new road crossing of the River Gade would increase the risk of
contamination of surface runoff due to accidental spillage of contaminants and from flushing
of pollutants from the impermeable surfaces. Contaminated surface runoff could enter and
pollute the River Gade main channel via overland flow or the River Gade culvert via the
surface water drainage system. This direct, adverse effect will be permanent. (Water
Quality)
7.5.20
The flow regime through the realigned River Gade channel may be altered from the current
state either because the main channel bed is not sealed. In this instance, water may be
exported or imported from the channel. This direct, adverse effect will be permanent.
(Water Quality)
Aquifer Receptor
7.5.21
The increase in impermeable area, in traffic volumes and activity, the PFS, car wash and the
new road crossing of the River Gade would increase the risk of contamination of surface
runoff due to accidental spillage of contaminants and from flushing of pollutants from the
impermeable surfaces. Contaminated surface runoff could enter and pollute the aquifer via
infiltration. This direct, adverse effect will be permanent. (Water Quality)
7.5.22
The increase in impermeable area will reduce the potential for surface contaminants to
infiltrate and pollute the shallow groundwater. This direct beneficial effect would be
permanent. (Water Quality)
Users of “The Link” Receptor
7.5.23
The Link will attract a large number of users to the site which will increase the overall level of
flood risk. (Flood risk)
Surrounding Users / Occupiers
7.5.24
The development of the site may increase the risk of off-site flooding. (Flood Risk)
Mitigation and Enhancement Measures
7.6.1
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The following mitigation and enhancement measures have been identified with regards to
the construction and operational phases of the development. The receptor to which the
mitigation / enhancement measure applies, and the effect addressed is presented in
parentheses at the end of each description.
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Construction Phase
General Working Practices
7.6.2
All permanent and temporary works affecting the River Gade will require consent under the
Land Drainage Act (1991) and Water Resources Act (1991) from the EA (Main River). Prior
to undertaking the construction works the applicant would seek the appropriate written
consent for the temporary works from the EA.
7.6.3
As a matter of course:
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
All construction works would be designed in accordance with the latest relevant EA
guidelines and the Technical Note on Workmanship and Materials for Drainage
Schemes (ADAS, 1995).

The principal contractor would take regard of the relevant EA Pollution Prevention
Guidelines (PPG) in preparation of its Construction Environmental Management Plan
(CEMP) and during the operation of the site.

Method statements would be agreed with the EA to ensure compliance with PPG prior to
the commencement of construction works to ensure that surface runoff quality is
managed during the construction process.

Contractors undertaking earthworks would develop risk assessments and method
statements covering all aspects of their work that have the potential to cause physical
damage to structures (e.g. water supply and sewerage infrastructure), mobilise large
quantities soil/sediments or block open watercourses. Earth moving operations would
be undertaken in accordance with BS 6031: 2009 Code of Practice for Earthworks.

Works affecting soils would follow the Good Practice Guide for Handling Soils (MAFF,
2000) which provides comprehensive advice on soil handling including stripping, soil
stockpiling and reinstatement.

Works would comply with the guidance in the Construction Code of Practice for the
Sustainable Use of Soils on Construction Sites (DEFRA, 2009) which provides guidance
on the use, management and movement of soil on site. This action should prevent the
mobilisation of sediment and prevent pollution of watercourses.

Good practice guidance on erosion and pollution control would be followed, e.g. CIRIA
Environmental Good Practice on Site (C650) and Control of Water Pollution from
Construction Sites (C532).

The principal contractor would avoid the storage of plant, machinery fuel or materials
(including soil stockpiles) alongside watercourses and in Flood Zones 2 or 3 unless
unavoidable. Construction works should be programmed as far as is practicable to
minimise soil handling and temporary soil storage.
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
The refuelling of plant, storage of fuels and chemicals and overnight storage of mobile
plant would be within the designated contractor’s compound areas. The compounds
would contain appropriate facilities for the storage of fuels and chemicals i.e. bundled
and locked storage containers, and would also be equipped with spill kits.
7.6.4
The adoption of best practice construction methods and construction management
processes would significantly mitigate many of the identified potential environmental effects
of the construction phase of the development.
7.6.5
The principal contractor may use alternative procedures compliant with their own
Environmental Management System. However, the broad approach and content would as a
minimum be comparable.
Site Specific Measures
7.6.6
Piling operations will be carried out to a protocol agreed with the EA, Affinity Water and
Thames Water. It is proposed that driven piles will be used for building foundations and
continuous flight augered piles for the bridge foundations, due to the proximity of Thames
Water’s underground assets. Details of the proposed groundwater protection measures are
presented in the Groundwater Mitigation Statement (see Appendix B.6). (Aquifer Receptor
- Water Quality)
7.6.7
Foul water from temporary staff welfare facilities would be contained within sealed storage
vessels and disposed of off-site to minimise the risk of surface or groundwater
contamination. (Aquifer Receptor; River Gade Receptor – Water Quality)
7.6.8
The principal contractor would avoid the storage of plant, machinery or materials in Flood
Zones 2 or 3 unless unavoidable. (Site workers, Surrounding users/occupiers Receptors –
Flood Risk)
7.6.9
The method statement for the realignment of River Gade is set out in the WFD Assessment
(Appendix A.2), including the measures that would be taken to mitigate potential adverse
effects on water quality. (River Gade Receptor – Water Quality)
Operational Phase
7.6.10
Thames Water will be surveying the alignment of the River Gade culvert and main foul sewer
through the site (both are Thames Water assets) to minimise the risk of either asset being
adversely affected by the construction works. (Site workers, Surrounding users/occupiers
Receptors – Flood Risk; Aquifer Receptor – Water Quality)
7.6.11
It has been agreed with the EA4 that the soffit level of the new bridges will be set to be not
less than the modelled 1 in 100 year plus climate change event plus 300 mm freeboard
based on modelled flood levels from the DBC (SFRA) hydraulic model of the River Gade.
(Surrounding users/occupiers Receptors – Flood Risk)
4
Telephone conversation between Trevor Brawn (EA) and Jenny Cavill (Weetwood), 10 December 2012
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7.6.12
It has been agreed with the EA4 that the abutments of the new bridges will be set back a
minimum of 1m from the bank top to ensure adequate conveyance capacity (and also to
provide a wildlife corridor under the bridges).
(Users of “The Link”, Surrounding
users/occupiers Receptors: Flood Risk)
7.6.13
Effective ongoing maintenance of the channel through the site will be necessary to prevent
the build-up of obstructions in the watercourse which may increase flood risk either on-site or
further downstream. An undeveloped buffer strip of around 8m for most of its length has
been provided adjacent to the River Gade for maintenance purposes (and to offer ecological
benefit). (Users of “The Link”, Surrounding users/occupiers Receptors: Flood Risk)
7.6.14
The surface water drainage system will be isolated from the underlying aquifer (i.e. no
infiltration devices) to protect the underlying aquifer from potential contamination from
polluted runoff, a stated requirement of Affinity Water. The new system will provide
betterment compared to the existing situation. (River Gade and Aquifer Receptors: Water
quality; Users of “The Link”, Surrounding users/occupiers Receptors: Flood Risk)
7.6.15
Further detail on the surface water drainage scheme is presented in the Drainage Strategy,
Appendix B.5. Key features are summarised below:
7.6.16
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
The external hard paved areas are to comprise a sealed surface with surface water
runoff collected via trapped gullies and linear drainage channels.

Surface runoff will pass via a sealed gravity drainage system to the existing surface
water outfalls for the site which are to the River Gade culvert. Peak runoff rates will be
restricted to a maximum discharge rate of 185 l/s for the 1 in 100 year return period
storm plus 20% climate change allowance using underground tanked cellular attenuation
systems and possible localised short term ponding within hard standing areas away from
main vehicular and pedestrian access/egress routes. This represents a reduction of
25% compared with peak run-off rates from the existing development.

All external vehicular areas are to discharge via Class 1 bypass separators to remove
oils and silts prior to discharge into the River Gade culvert.

Additional catchpits will be incorporated in the system directly upstream of each unit to
further assist in the removal of silts and oils from the surface water runoff. The bypass
separators will be fitted with oil high level alarms, designed and tested to BS EN8581:2002 as required by PPG3.

Surface runoff from the paved area of the PFS will discharge via a specialist forecourt
separator to the foul water system. The system will be fitted with an automatic closure
device to prevent oil passing downstream and an oil high level alarm to notify the
operator if the tank requires emptying between the regular maintenance intervals.
The design of the PFS will incorporate a package of mitigation measures. (River Gade
Receptor; Aquifer Receptor – Water Quality)
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7.6.17
Further details on the PFS installation are provided in the PFS Specifications (Appendix
B.7). Key features are summarised below:

The PFS will make use of above ground storage tanks. This measure avoids the risks
that failure of a below ground storage facility would present to the aquifer. The tanks will
be provided with a fully welded and tested outer second steel skin to provide secondary
containment with a capacity of 110% of the tank capacity, as required under the Control
of Pollution (Oil Storage) (England) Regulations 2001. The tanks will meet the
requirements set down in the new revision of the ‘Design, Construction, Modification,
Maintenance and Decommissioning of Filling Stations’.

Underground pipes between the tanks will be double skinned.

The tanks will have the facility for overfill to be directed into secondary containment.

Leak detection will be provided by a discriminating sensor located within the secondary
containment system; this will be connected to the gauging system and will trigger an
alarm if any product enters the void.
7.6.18
To check that the sealing of the site from the underlying is effective, borehole monitoring for
total petroleum hydrocarbons will be undertaken during the operational phase at locations
agreed with the EA and Affinity Water. (River Gade Receptor; Aquifer Receptor – Water
Quality)
7.6.19
Hydro-geomorphological monitoring will be undertaken on an annual basis to ensure that the
features are developing as intended. Particular note will be taken of gravel features, any
siltation and bank erosion. (River Gade Receptor: Water Quality, Hydrology)
7.6.20
Dissolved oxygen concentrations will be monitored in conjunction with the biological
monitoring. (River Gade Receptor: Water Quality, Hydrology)
7.6.21
The realigned river channel will be clay-lined within the low flow channel ensuring that flows
are retained throughout the diverted section and not lost to the ground. Lining is preferred
by Thames Water in relation to their assets (foul sewer and surface water culvert) which will
be partly beneath the diverted river. A typical lining arrangement is presented in Appendix
A.2 WFD Assessment. (River Gade Receptor: Water Quality)
7.6.22
The existing river bed comprises chalk gravel but siltation is present in some areas and there
is a lack of variety in the flow regime. It is proposed that an improved pool-riffle sequence
will be achieved by use of chalk groynes as current deflectors at intervals to produce
narrowing of the channel and thus higher velocity riffle areas. This will provide sections
where siltation of the gravel and pebble substrate will not occur. Pool sections will also be
achieved without the use of weirs that provide barriers to fish movement. (River Gade
Receptor: Water Quality)
7.6.23
The diversion to the river provides space to to create off-line wetlands. These will provide a
silty substrate with a deeper area of open water, surrounded by marginal areas of
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watercress, sedge and reeds. A diversity of bank gradient and form (straight, scalloped) will
be incorporated around the margins. (River Gade Receptor: Water Quality)
7.6.24
The realigned channel will be designed to provide comparable conveyance capacity to the
existing channel so as not to increase flood risk on site or further downstream. (Users of
“The Link”, Surrounding users/occupiers Receptors: Flood Risk)
7.6.25
The proposed new wetland areas will increase flood storage on site thereby reducing flood
risk on site and downstream. (Users of “The Link” and River Gade Receptor: Flood Risk)
7.6.26
During initial operation of the new river channel, monitoring will be undertaken to ensure that
gravel features are developing as predicted and that excessive siltation is not taking place.
In the event of any difficulties, the problem will be discussed with the EA and appropriate
refinement of the bedform agreed and implemented. Further details are presented in
Chapter 8 of this ES. (River Gade Receptor – Water Quality)
7.6.27
The layout of the proposed development has been sequentially led with respect to flood risk.
The new college buildings and superstore located to the east of the River Gade are located
in Flood Zone 1. The risk of flooding from other sources is assessed to be low and no
further flood risk mitigation measures are deemed to be required. (Users of “The Link”,
Surrounding users/occupiers Receptors: Flood Risk)
7.6.28
The removal of the southernmost existing college building to the west of the River Gade
provides an opportunity to create additional flood storage on the site by reducing ground
levels below the modelled 100 year flood level. (Users of “The Link”, Surrounding
users/occupiers Receptors: Flood Risk)
Residual Effects
7.7.1
Mitigation measures for the adverse risks identified for the construction and operational
phases of the proposed development have been identified, including design and risk
assessment controls, and operational controls/working methods and monitoring.
7.7.2
A summary of the (post mitigation) residual effects are presented in Table 7.6. Further
commentary on these follows below.
Construction Phase
7.7.3
The significance of residual environmental effects during the operational phase are
summarised below and in Table 7.6(a).
7.7.4
However, the significance of potential residual effects on the underlying aquifer is assessed
to be Minor / Moderate Adverse. However, it is noted that the construction period is short
term (approximately one year) and this will further mitigate the likelihood and potential
magnitude of either adverse impact occurring, over and above the specific mitigation
measures presented in this chapter.
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Operational Phase
7.7.5
The significance of environment effects during the operational phase are summarised below
and in Table 7.6(b).

The operational phase of the development is not assessed to have any significant
adverse environmental effects.

Also, with respect to the River Gade, the river diversion is assessed to have a potential
minor benefit on the River Gade within the site in terms of habitat, hydromorphology,
chemical and biological quality improvements.
Chemical and water quality
improvements would also be expected to improve downstream of the site.
Table 7.6: Summary of Potential (Post Mitigation) Residual Effects
(a)
Construction Phase
Receptor
(Importance)
Environmental Impact
Nature
Magnitude
Significance
River Gade (High)
Water quality
Small adverse
Minor adverse
Aquifer (Very High)
Water quality
Small adverse
Minor / Moderate
adverse
Site workers (High)
Flood risk
Negligible
Not significant
Surrounding users /
occupiers (High)
Flood risk
Negligible
Not significant
(b)
Operational Phase
Receptor
(Importance)
Environmental Impact
Nature
Magnitude
Significance
River Gade (High)
Water quality
Small benefit
Minor benefit
Aquifer (Very High)
Water quality
Small benefit
Minor / Moderate
benefit
Users of “The Link”
(High)
Flood risk
Negligible
Not Significant
Surrounding users /
occupiers (High)
Flood risk
Negligible
Not significant
Cumulative Impacts
7.7.6
Considering the findings of the assessment, no potential cumulative effects on hydrology and
drainage receptors have been identified resulting from the proposed development or its
interaction with other known or potential local development activities.
Summary
7.8.1
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This chapter considers potential impacts on hydrology and drainage receptors that could be
affected by the proposed development or could impact on the proposed development.
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7.8.2
Mitigation measures for the adverse risks identified for the construction and operational
phases of the proposed development have been identified, including design and risk
assessment controls, operational controls/working methods and monitoring.
7.8.3
The construction phase mitigation measures would significantly reduce the risks to the
identified receptors. Despite this, small to moderate adverse residual effects remain, due
primarily to the scale of the project and the importance and sensitivity of the River Gade and
aquifer receptors. However, the likelihood of the risks materialising will be reduced by the
limited duration of some of the construction activities.
7.8.4
There are no identified adverse residual effects during the operational phase of the
development. Indeed, the improvements to the site drainage systems will provide
environmental improvements compared to the existing situation by attenuating surface water
runoff and the sealing off of the aquifer beneath the site. The realignment of the River Gade
also presents an opportunity to improve the quality of the watercourse through the site.
References
Redevelopment of West Herts College site – Water Framework Directive Assessment, April
2013, AMEC
Applied Geology, 2013, “Ground Investigation at West Herts College and Morrisons Store
Marlowes, Hemel Hempstead”, Report no. AG1701-12-P84, April 2013
British Hydrological Society, Chronology of Flooding, available online at
www.dundee.ac.uk/geography/cbhe
British Standards Institute, 2011, “BS 8533:2011, Assessing and Managing Flood Risk in
Development – Code of Practice”, October
Building Regulations Approved Document H
Centre for Ecology and Hydrology, 2009, Flood Estimation Handbook CD-ROM 3, 2009.
CIRIA, 2007, “The SUDS Manual”, 2007
Defra, 2009. “Construction Code of Practice for the Sustainable Use of Soils on Construction
Sites”. Available from: www.defra.gov.uk
Dacorum Borough Council, 2007, Level 1
Berkhampstead and Hemel Hempstead, August.
Strategic
Flood
Risk
Assessment
-
Dacorum Borough Council, 2008, Level 2
Berkhampstead and Hemel Hempstead, June.
Strategic
Flood
Risk
Assessment
-
Department of Communities and Local Government, 2012, National Planning Policy
Framework and Technical Guidance, April
Environment Act, 1995
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Environment Agency, 2005, “Preliminary Rainfall Runoff Management for Developments”,
R&D Technical Report W5-074/A/TR/1 Revision C.
Environment Agency, 2007, “Water Abstraction – Getting the Balance Right; The Colne
Catchment Abstraction Management Strategy, December.
Environment Agency, 2009, “Water for Life and Livelihood – River Basin Management Plan –
Thames River Basin District”, December.
Environment Agency, 2011, “ WFD: Method Statement for the Classification of Surface
Water Bodies – Monitoring Strategy”, v2.0, July
Environment Agency Pollution Prevention Guidelines (PPGs) – as referenced in main body
of text.
Environment Agency, undated, “WFD: Groundwater Chemical Status Assessment
(Classification) and Trend Assessment – Method Statements”.
Environment Agency, undated, “Groundwater Projection Policy and Practice (GP3)”,
Available from: www.environment-agency.gov.uk/research/library/publications/40741.aspx
Environmental Simulations International, 2005, “Chalk of the Mid-Chilterns and Colne
Valley”, Prepared for the EA
EU Water Framework Directive, December 2000
Groundwater Directive (80/68/EEC), December 1979
Hertfordshire County Council, 1960, “Site Plan and Drainage Layout - Hemel Hempstead
College of Further Education”, Drawing number E446/101/3, Architects Dept., June
Integrated Pollution Prevention and Control (IPPC) Directive (2008/1/EC)
MAFF, 2000, “Good Practice Guide for Handling Soils”, (Version 04/00). Cambridge: FRCA.
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8
Ecology & Nature Conservation
Introduction
8.1.1
AMEC E&I (AMEC) was commissioned to prepare an Ecology and Nature Conservation
chapter as part of the Environmental Impact Assessment (EIA) for the proposed redevelopment of the existing West Herts College (WHC) site at Hemel Hempstead.
8.1.2
The approach is based on Institute of Ecology and Environmental Management (IEEM)
guidance issued in 2006, which represents current best practice.
8.1.3
The scope of this assessment has been defined through desk study, extensive ecological
survey and a formal scoping process. This approach accords with the requirements of the
EIA Regulations, which require consideration only of likely significant effects and do not
require consideration in detail of effects on every species or habitat that may be present if
they are unlikely to be significant.
8.1.4
This chapter also describes the methods used to determine the impacts of the development
on current baseline conditions, the mitigation measures incorporated within the scheme to
prevent, reduce or offset any adverse impacts and any likely residual effects after these
measures have been implemented. The effects of the proposed development considered
are those both during construction and operation and take into account direct, indirect,
cumulative, residual, short, medium and long-term, beneficial and adverse effects of the
proposed development.
8.1.5
The proposals have been developed with the existing ecological resources of the site in
mind, balancing impacts on particular species or habitats through an iterative process.
Therefore, ecological mitigation and enhancement measures form an integral part of the
development proposals and have been designed specifically to reduce or avoid ecological
impacts.
Policy Context
8.2.1
National and local policies relating to biodiversity may have a bearing on the scope of the
assessment of effects on biodiversity. The following section lists the policies and policy
issues which have been considered in assessing effects on biodiversity.
National Planning Policy Framework
8.2.2
The National Planning Policy Framework (NPPF) was published in March 2012 and replaces
the previous planning policy statement (PPS 9) on biodiversity. The NPPF states in Chapter
9 paragraph 118 the following in relation to biodiversity and planning:
“When determining planning applications, local planning authorities should aim to conserve
and enhance biodiversity by applying the following principles:
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8.2.3

If significant harm resulting from a development cannot be avoided (through locating on
an alternative site with less harmful impacts), adequately mitigated, or, as a last resort,
compensated for, then planning permission should be refused;

Proposed development on land within or outside a Site of Special Scientific Interest
likely to have an adverse effect on a Site of Special Scientific Interest (either individually
or in combination with other developments) should not normally be permitted. Where an
adverse effect on the site’s notified special interest features is likely, an exception
should only be made where the benefits of the development, at this site, clearly
outweigh both the impacts that it is likely to have on the features of the site that make it
of special scientific interest and any broader impacts on the national network of Sites of
Special Scientific Interest;

Development proposals where the primary objective is to conserve or enhance
biodiversity should be permitted;

Opportunities to incorporate biodiversity in and around developments should be
encouraged;

Planning permission should be refused for development resulting in the loss or
deterioration of irreplaceable habitats, including ancient woodland and the loss of aged
or veteran trees found outside ancient woodland, unless the need for, and benefits of,
the development in that location clearly outweigh the loss; and the following wildlife sites
should be given the same protection as European sites:

potential Special Protection Areas and possible Special Areas of Conservation;
listed or proposed Ramsar sites; and

sites identified, or required, as compensatory measures for adverse effects on
European sites, potential Special Protection Areas, possible Special Areas of
Conservation and listed or proposed Ramsar sites”.
The presumption in favour of sustainable development does not apply where development
requiring appropriate assessment under the Birds or Habitats Directives is being considered,
planned or determined.”
UK Biodiversity Action Plan
8.2.4
Following the signing of the Convention on Biological Diversity at the Earth Summit in 1992,
the UK government committed to take action to conserve native species and habitats. The
UK Biodiversity Action Plan set out a national strategy developed to achieve this aim.
8.2.5
In June 2007, following a review, a revised list of habitats and species considered to be
priorities for action was published for consultation. This was accepted by the Government in
August 2007 and has been adopted such that these additional habitats and species are also
afforded protection through the planning process.
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8.2.6
The UK Biodiversity Action Plan has been superseded by the UK post-2010 Biodiversity
Framework but the UK BAP lists of priority habitats and species remain an important and
valuable reference source and have been used to help to draw up the statutory list of
habitats and species which are of principal importance for the conservation of biodiversity in
England under the NERC Act (see section 8.2.11). The UK BAP lists have been used in this
report, in addition to the statutory lists, in identifying valued ecological receptors.
Local Planning Policy
8.2.7
The Development Plan for Dacorum Borough Council includes:

Saved policies of the Dacorum Borough Local Plan (adopted 2004): and

The Emerging Local Development Framework.
Saved policies of the Dacorum Borough Local Plan:
8.2.8
The Dacorum Borough Local Plan was adopted in 2004 and as of 26 September 2007 all
policies in the Adopted Local Plan are saved apart from Policy 27 on gypsy sites. Relevant
saved policies include:


Policy 11 ’Quality of Development’ outlines a number of design criteria which
developments will be expected to meet. These include:

(b) retain and supplement important trees and shrubs, and where relevant includes
measures to enhance the local landscape;

(j) avoid harm arising from pollution in all its forms, including air, water, noise and
light pollution. In particular there should be no detrimental effect on air quality in
sensitive areas (especially where traffic related air pollution problems arise);
Local Plan Policy 99 ‘Preservation of Trees, Hedgerows and Woodlands’ seeks to
preserve trees, hedgerows and woodlands throughout the borough.
Dacorum Core Strategy
8.2.9
The Core Strategy is likely to be adopted in summer 2013 and will supersede some policies
of the local plan. Relevant policies from the Pre-submission Draft (2011) and proposed
modifications (2013) include:


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Policy CS10 ‘Quality of Settlement Design’ sets out that the design of new development
should consider a number of criteria including:

preserve and enhance green gateways; and

protect and enhance wildlife corridors.
Policy CS26 ‘Green Infrastructure’ states that the Green Infrastructure Network will be
protected, extended and enhanced. Development and management action will
contribute towards: the conservation and restoration of habitats and species; the
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strengthening of biodiversity corridors; the creation of better public access and links
through green space; and a greater range of uses in urban green spaces.
8.2.10

Policy CS31’ Water Management’ requires development to avoid Flood Zones 2 and 3
(with a flood risk assessment being required for development in these areas), minimise
water run-off, secure opportunities to reduce the cause/impact of flooding and secure
opportunities to conserve and enhance biodiversity and avoid damage to groundwater
protections zones.

Policy CS32 ‘Soil, Air and Water Quality’ states that any development proposals which
would cause harm from a significant increase in pollution (into the air, soil or any water
body) by virtue of the emissions of fumes, particles, effluent, radiation, smell, heat, light,
noise or noxious substances, will not be permitted.
A Biodiversity Action Plan (BAP) exists for Hertfordshire and was originally prepared in 1998.
The action plan is Hertfordshire’s response to the national biodiversity planning process and
takes the objectives and targets of the UK Biodiversity Action Plan and translates and
amplifies these within a local context. It is intended to provide a consensus on the priorities
for conservation action within Hertfordshire.
Legislative requirements
8.2.11
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In preparing this EIA, account has been taken of relevant legislation and regulations, namely:

The Natural Environment and Rural Communities Act 2006 (NERC Act) came into
force on 1st Oct 2006. Section 41 (S41) of the Act requires the Secretary of State to
publish a list of habitats and species which are of principal importance for the
conservation of biodiversity in England. The list has been drawn up in consultation with
Natural England, as required by the Act.

The Conservation of Habitats and Species Regulations 2010 (hereafter referred to
as the Habitat Regulations): These consolidate all the various amendments made to
the Conservation (Natural Habitats, &c.) Regulations 1994 in respect of England and
Wales. The Regulations provide for the designation and protection of 'European sites',
the protection of 'European protected species' and the adaptation of planning and other
controls for the protection of European Sites. The Regulations also make it an offence
(subject to exceptions) to deliberately capture, kill, disturb, or trade in the animals listed
in Schedule 2.

The Wildlife and Countryside Act 1981 (as amended) provides the main legal
framework for nature conservation and species protection in the UK. The SSSI is the
main statutory nature conservation designation in the UK. Such sites are notable for
their plants, or animals, or habitats, their geology or landforms, or a combination of
these.
Natural England is the key statutory agency in England for advising
Government, and for acting as the Government’s agent in the delivery of statutory
nature conservation designations. Designation of a SSSI is a legal process by which
sites are notified under the Wildlife and Countryside Act 1981. The 1981 Act makes
provision for the protection of sites from the effects of changes in land management,
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and owners and occupiers receive formal notification specifying why the land is of
special scientific interest, and listing any operations likely to damage the special
interest.

The Countryside and Rights of Way Act 2000: provides supplementary protected
species legislation.

The Protection of Badgers Act 1992 makes it an offence to kill injure or take a badger
from the wild. It is also an offence to damage or interfere with a sett unless a licence is
obtained from a statutory authority.
Methodology
Baseline Data Collection
Desk study
8.3.1
A data-gathering exercise was carried out in August 2012 to obtain information relating to
statutory and non-statutory nature conservation sites, priority habitats and species and
legally protected species. Full details of the results of this data gathering exercise are
presented in the Baseline Biodiversity Report located in Appendix C.1.
8.3.2
Given the potential for the proposed development to affect biodiversity resources located offas well as on-site, data were obtained for:
8.3.3

sites of international nature conservation interest located within 10km of the site
boundary;

sites of national nature conservation interest located on or within 5km of the site
boundary;

sites of county nature conservation interest located within 1km of the site boundary; and

records of legally protected and priority species to a distance of 1km from the site
boundary.
Sources of desk study information are listed in Table 8.1.
Table 8.1: Sources of desk study information
Topic
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Source of information
Statutory nature conservation sites
Multi-Agency Geographic Information for the
Countryside website http://magic.defra.gov.uk/
Non-statutory nature conservation sites
Hertfordshire Biodiversity Records Centre
Ancient woodland
Multi-Agency Geographic Information for the
Countryside website
http://magic.defra.gov.uk/
Records of legally protected and notable/priority
species
Hertfordshire Biodiversity Records Centre
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Survey work
8.3.4
A summary of the biological surveys carried out in support of the EIA for the site is provided
in Table 8.2. The methodologies for, and results of, these surveys can be found in the
Baseline Biodiversity Report located in Appendix C.1 and the Water Framework Directive
Assessment Report located in Appendix A.2.
Table 8.2: Baseline surveys
Survey requirement
Survey specification
Date
Reference
Habitat mapping within Extended Phase 1 habitat
site boundary
survey
2012
Baseline Biodiversity Report
/AMEC(2013)/Appendix C.1.
Bats
Habitat suitability survey,
building inspection, building
emergence survey and bat
activity survey
2012
2013
Baseline Biodiversity Report /
AMEC (2013) Appendix C.1.
Otter and water vole
Riparian mammal survey
2012
Baseline Biodiversity Report /
AMEC (2013 Appendix C.1.
Macroinvertebrate
survey
Analysis of four kick samples/
assessment of BMWP and
LIFE scores and rare/notable
invertebrates
2012
Appendix F of the Water Framework
Directive Assessment
/AMEC(2013)/Appendix A.2.
Aquatic and marginal
plants
Macrophyte survey
2012
Appendix G of the Water
Framework Directive Assessment
/AMEC(2013)/Appendix A.2.
River survey
River Habitat Survey (RHS)
2012
Appendix D of the Water Framework
Directive Assessment
/AMEC(2013)/Appendix A.2.
River survey
River Corridor Survey (RCS)
2012
Appendix E of the Water Framework
Directive Assessment
/AMEC(2013)/Appendix A.2.
Further surveys
8.3.5
No further biological survey work is considered necessary, albeit depending on the timing of
the removal of vegetation, checks for nesting birds may be required. However, a need for
further surveys of river habitat, involving surface and subsurface sampling of river bed
substrate is recognised. This is discussed further in the Water Framework Directive
Assessment in Appendix A.2.
Consultation
8.3.6
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AMEC’s proposals with regards to the river diversion and enhancements were presented to
the Environment Agency on 11 April 2013 and AMEC consulted with Clarke Gordon and
Rachel Keen from the Environment Agency via telephone conversations held between
November 2012 and June 2013. The proposals were then amended in response to their
feedback and a further draft supplied for comment on 13th June 2013.
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8.3.7
AMEC met with Nathalie Bateman and Claire Covington of Dacorum Borough Council on
21st May 2013 to discuss river corridor aspects of the proposals.
8.3.8
A meeting was held between Dacorum Borough Council and the Environment Agency on 3rd
June 2013, with the local MP (Mike Penning) and representatives from AMEC, BSCP and
Weetwood in attendance, to discuss river diversion issues.
Assessment methodology
Methodology for identifying potential receptors and prediction of effects
8.3.9
The first part of the assessment process was to undertake a scoping exercise. This involved
differentiating the biodiversity receptors (i.e. designated sites, habitats and species’
populations) that could be significantly affected by the proposed development and that
therefore required more detailed assessment, from those receptors that are not likely to be
significantly affected and did not require further assessment (i.e. they were ‘scoped-out’ of
the assessment).
8.3.10
The first stage of this approach involved using baseline data (collected by the desk study
and field surveys) for the development site and up to 2km away (up to 10km away for
European designated nature conservation sites)5 to determine:

which, if any of the species that have been recorded are legally protected or controlled
(see Appendix C.1); and/or

which, if any, sites, areas of habitat and species that have been recorded are of
importance for biodiversity conservation, notwithstanding any legal protection that they
may have (see Appendix C.1).
8.3.11
Use of these categories provides a robust and objective basis for focusing the assessment
on receptors that are widely recognised to be important for the conservation of biodiversity in
addition to those that are legally protected. It should be noted, however, that legally
protected species may be protected for reasons other than for biodiversity conservation (e.g.
badger, which is protected for welfare reasons).
8.3.12
For sites/habitats/species that are important for biodiversity conservation, the next stage of
the scoping assessment was to determine whether the receptors are likely to be of sufficient
‘value’ that an impact upon them could be significant. In this context, value refers to a
receptor being of sufficient quality (for sites and habitats) or size (for sites, habitats or
species’ populations). The distinction between importance and value can be illustrated by
the great crested newt, which, as well as being legally protected, is important at a national
level because it is a species of principal importance for biodiversity. However, depending on
the local abundance of this species, a small affected population might be anywhere between
low or high biodiversity value.
5
There was also the possibility that other receptors could be identified as potentially being affected, based on the
study team’s experience of the local area.
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8.3.13
The findings of the valuation of important receptors, together with information about whether
receptors are legally protected, are set out in Box 2.1 of Appendix C.1. For those receptors
that are assessed as being of insufficient value for impacts to be significant, this appendix
provides a justification for this conclusion.
8.3.14
Important receptors that are of sufficient value that an impact upon them could be significant,
together with all legally protected species, were then taken through to the next stage of the
scoping assessment. This involved identifying, for each receptor, any environmental
changes that are likely to be caused by the proposed development, which have the potential
to lead to a significant impact. Then the area was determined within which the
environmental change could cause a significant impact on the receptor; this area is referred
to as an ‘ecological zone of influence’. The area where the receptor occurs was then
compared with the ecological zone of influence. If the receptor occurs or is likely to occur
within the zone of influence it was ‘scoped in’ for further assessment.
8.3.15
The ecological zone of influence that is the most straightforward to define is the area
affected by land take and land cover changes associated with the development. This zone is
the same for all affected receptors. By contrast, for each environmental change that can
extend beyond the area affected by land take and land cover change (e.g. changes in noise),
the zone of influence may vary between receptors, dependent upon the receptors’ sensitivity
to the change and the precise nature of the change.
8.3.16
For example, one bird species might be unaffected by noise unless the noise is generated
very close to where the bird nests, whilst another bird species might be disturbed at much
greater distances; other species (e.g. of invertebrate) may be unaffected by changes in
noise. A further complication is that the response of a receptor to a change associated with
one development may differ to the response of the same receptor to a similar change on
another development. This can occur as a result of the wide range of variables that
influences the precise nature of any change (e.g. for noise this can include differing baseline
noise conditions, specific magnitude, timing or other characteristics of the noise and the
effects of screening and topography).
8.3.17
In view of these complexities, the definition of the zones of influence that extend beyond the
land take area was based upon professional judgement, informed by discussions with the
technical specialists who were working on other chapters of the ES. These specialists
provided information about the environmental changes that they assessed in their ES
chapters. This information was then combined with available ecological information about
different receptors’ sensitivity to different environmental changes in order to define the extent
of each ecological zone of influence. The potential outcome of this was that a zone of
influence could be so extensive that a larger than expected species population or area of
habitat could be affected, which in turn could lead to the potential for an impact to be
significant when it was previously assessed that this would be unlikely. As a consequence,
receptors that were initially scoped-out could be scoped back into the assessment.
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8.3.18
Each relevant receptor (i.e. that is of sufficient value or is legally protected, as described
above), which was located wholly or partly within one or more zones of influence, was then
subject to further scoping assessment in relation to the relevant environmental change(s).
The spatial extent of this assessment reflected the area occupied by the receptor. Thus, if
part of a designated nature conservation site was located within a zone of influence, an
assessment was made of the impacts on the site as a whole. A similar approach was taken
for areas of notable habitat. For species that occur within an ecological zone of influence, an
assessment was carried out on the total area that is used by the affected individuals of the
species (e.g. for foraging or as a breeding territory). 6
8.3.19
This final stage of the scoping assessment involved drawing upon available information
about the magnitude and other characteristics of the environmental changes and the
sensitivity of each relevant receptor to these changes, to arrive at a conclusion about the
potential for a significant impact to occur. Where there was the potential for a significant
impact, or contravention of protected species legislation, the receptor was taken forward for
further ‘post-scoping’ assessment.
Assessment Methodology
8.3.20
The weight to be attached to identified impacts is a matter for the decision maker. To assist
that consideration, however, this ES is based on a clear approach to the assessment of
significance. In particular, the potential significance of predicted impacts has been
determined by reference to relevant criteria for each assessment topic. Broadly, the
significance of the impact is determined with reference to the magnitude of the potential
impact, the value or sensitivity of the receiving environment or receptor, the likelihood of the
impact occurring, its duration and the extent to which it is reversible. In order to provide a
consistent approach to expressing the outcomes of each of the assessments undertaken,
the terminology described below has been used to assist in determining the significance of
the identified impacts. An Impact Assessment Matrix (IAM) has been developed and this
has been used to enable, where appropriate, a consistent approach to setting the level of
impact significance across the different EIA topics. Where necessary, the evaluation of
impacts has been informed and moderated by professional judgement.
Magnitude
8.3.21
The magnitude of a potential impact refers to the extent of change, which is defined in terms
of the area over which the impact occurs, the duration (i.e. the time for which the impact is
expected to last prior to recovery or replacement of the resource or receptor), the likelihood
(i.e. the chance that the impact will occur) and reversibility. An irreversible (permanent)
impact is one from which recovery is not possible within a reasonable timescale or for which
there is no reasonable chance of action being taken to reverse it.
6
The affected individuals may, for example, be a pair of birds, a badger clan associated with a main sett or the
population of great crested newts in a pond. Where appropriate, the area for which data were required was
extended (e.g. to include other pairs of birds in a discrete subpopulation, or a metapopulation of newts).
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8.3.22
In order to help define the impact magnitude, the following guidelines (see Table 8.3) have
been adopted for the purposes of this EIA. While this table provides guidelines of a generic
nature, it should be noted that more specific guidelines in relation to impact magnitude have
been adopted for the topics assessed where considered necessary.
Table 8.3: Generic Guidelines for the Assessment of Magnitude
8.3.23
Magnitude
Guidelines
High
Very significant, permanent/irreversible changes, over the whole development
area and potentially beyond (i.e. off-site), to key characteristics or features of
the particular environmental aspect’s character or distinctiveness. Impact
certain or likely to occur.
Medium
Significant, permanent/irreversible changes, over the majority of the
development area and potentially beyond, to key characteristics or features of
the particular environmental aspect’s character or distinctiveness. Impact
certain or likely to occur.
Low
Noticeable, temporary (during the project duration) change, over a partial area,
to key characteristics or features of the particular environmental aspect’s
character or distinctiveness. Impact would possibly occur.
Very Low
Noticeable, temporary (for part of the project duration) change, or barely
discernible changes for any length of time, over a small area, to key
characteristics or features of the particular environmental aspect’s character or
distinctiveness. Impact unlikely or rarely to occur.
The adopted guidelines have been phrased to cover the range of change and duration of
impact that might be expected, from very significant through to barely discernible. It is
considered that this range takes account of the wide variation of potential change that could
occur. However, as with all of the steps in the impact assessment process, there is scope
for the application of professional judgement in the assignment of assessed magnitude, such
that further qualification might be used in determining the magnitude level. While the table
above provides generic guidelines, more specific assessment criteria in relation to the
definition of impact magnitude are provided within each of the topic-specific chapters where
appropriate.
Receptor Value and Sensitivity
8.3.24
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The value of the receptor is a function of a range of factors (e.g. biodiversity value,
social/community value and economic value). The value or potential value of a resource or
feature can be determined within a defined geographical context. For example, the following
hierarchy to describe value is recommended by the Institute of Ecology and Environmental
Management (IEEM) (2006) with respect to ecological receptors:

International;

National (i.e. England/Northern Ireland/Scotland/Wales);

Regional/county/metropolitan area/large distrct or unitary authority;

Local.
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8.3.25
The sensitivity of an environmental receptor is a function of its capacity to accommodate
changes in baseline conditions resulting from the development and/or as a result of ongoing
natural processes and also reflects its capacity to recover if it is affected.
8.3.26
In order to help define the value and sensitivity of receptors, the following guidelines (shown
in Table 8.4 below) have been adopted in this EIA. It should be noted that the value and
sensitivity criterion is a composite one. In some instances, the inherent value of a receptor
has been recognised by the expert community and Governmental bodies by means of
designation and the ‘value’ element of the composite criterion, in turn, recognises and gives
weight in the assessment to that designation. Irrespective of recognised value, all receptors
will exhibit a greater or lesser degree of sensitivity to the changes brought about by the
proposed development and the ‘sensitivity’ element of the criterion ensures that this
characteristic of each receptor is brought into the assessment also; weighting being a matter
of judgement applied by the expert assessor. The precise form which these indicators take
in each case will vary according to subject matter but by following the generic methodology
explained in this Chapter, the assessors responsible for each of the topic-specific
assessments have ensured that these factors have been taken into account within their
subject areas. These impact significance ratings provide initial guidance to the assessor
who then applies expert professional judgement to reach a balanced conclusion on the
ultimate significance of a particular impact.
Table 8.4: Generic Guidelines for the Assessment of Value and Sensitivity
Value/
Sensitivity
Very high
Description
Value: Feature/receptor possesses key characteristics which contribute
significantly to the distinctiveness, rarity and character of the site/receptor (e.g.
designated features of international/national importance, such as Special Areas
of Conservation (SACs), Special Protection Area (SPAs), Ramsar sites,
Sensitivity: Feature/receptor has a very low capacity to accommodate the
proposed form of change.
High
Value: Feature/receptor possesses key characteristics which contribute
significantly to the distinctiveness and character of the site/receptor (e.g. Sites of
Special Scientific Interest (SSSIs), National Nature Reserves (NNRs), UK
Biodiversity Action Plan (BAP) habitats, etc.)
Sensitivity: Feature/receptor has a low capacity to accommodate the proposed
form of change.
Medium
Value: Feature/receptor only possesses characteristics which are locally
significant. Feature/receptor not designated or only designated at a local level
(e.g. designated features of regional or county importance, such as Local
Wildlife Sites (LWSs), Local BAP, local nature reserves, trees with TPO etc).
Sensitivity: Feature/receptor has some tolerance to accommodate the proposed
change.
Low
Value: Feature/receptor characteristics do not make a significant contribution to
local character or distinctiveness. Feature/receptor not designated.
Sensitivity: Feature/receptor is generally tolerant and can accommodate the
proposed change.
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Significance
8.3.27
The concept of ‘significance’ is central to the assessment process. The classification of
significance aids the identification of the principal environmental impacts of the proposed
development and assists in determining what weight should be given to these impacts.
8.3.28
There is no statutory definition of what constitutes a significant impact and guidance is of a
generic nature. However, it is widely recognised that ‘significance’ reflects the relationship
between the magnitude of an impact and the value/sensitivity of the affected resource or
receptor.
8.3.29
To assist in the assessment process, an impact assessment matrix (IAM) has been used in
determining the level of environmental impact (see
For example, an effect may be
determined to be of such a low magnitude in relation to a receptor with very high value, for
example a European wildlife site, that the impact is determined by expert consideration of
the individual circumstances to be negligible.
8.3.30
Impacts classed as major or moderate are regarded as significant, while minor and negligible
impacts are classed as not significant, for the purpose of assisting decision-makers.
8.3.31
Table 8.5). It should be noted that while the matrix provides an appropriate framework for
the consistent assessment of impacts across all environmental topics, there is still an
important role for expert judgement and further objective assessment to play in moderating
the significance of an impact. Given that the criteria represent levels on a continuum (or
continuous gradation), professional judgement and awareness of the relative balance of
importance between value/sensitivity and magnitude is required. For example, an effect may
be determined to be of such a low magnitude in relation to a receptor with very high value,
for example a European wildlife site, that the impact is determined by expert consideration of
the individual circumstances to be negligible.
8.3.32
Impacts classed as major or moderate are regarded as significant, while minor and negligible
impacts are classed as not significant, for the purpose of assisting decision-makers.
Table 8.5: Impact Assessment Matrix
Magnitude
8.3.33
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Value and Sensitivity of Receptor
Low
Medium
High
Very high
Very Low
Negligible
Negligible
Minor
Minor
Low
Negligible
Minor
Minor
Moderate
Medium
Minor
Minor
Moderate
Major
High
Minor
Moderate
Major
Major
For the purpose of this impact assessment, statutory designations and any potential
breaches of environmental legislation take precedence in determining significance, because
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the protection afforded to a particular receptor or resource has already been established as a
matter of law. Thus, using the defined criteria and IAM, features to which designations apply
will normally be allocated a higher value than non-designated features and, as a result, any
impact tends to be of a greater significance than an impact on features to which no
designation applies. Where a site is designated at international and national level for the
same interest features, the international designation is the criterion used to set the value.
8.3.34
In practice, and given the role of informed professional judgement in the assessment
process, there may be some variation between subject areas in the impact assessment
process. This may be as a result of limited information on the sensitivity of features and/or
the complexity of interactions that require assessment in determining the magnitude of
change.
Baseline Conditions
Desk study results
8.4.1
An overview of the biodiversity baseline for the site is presented in this section. Detailed
results of the desk studies and surveys are presented in the Baseline Biodiversity Report
located in Appendix C1.
Statutory nature conservation sites
8.4.2
There is one statutory nature conservation site that is of international importance located
within 10km of the site boundary. This is Chilton Beechwoods Special Area of Conservation
(SAC), located 5.58 km to the north-west of the site boundary, which is of importance as it is
represents a very extensive tract of the Annex I habitat Asperulo-Fagetum beech forests,
located in the centre of the habitat’s UK range. This type of Annex I habitat occurs on
circumneutral to calcareous soils and mostly corresponds to NVC type W12 Fagus sylvatica
– Mercurialis perennis woodland. In addition, some of the more calcareous stands of NVC
type W14 Fagus sylvatica – Rubus fruticosus woodland are also included within this habitat
type.
8.4.3
The woodland is an important part of a grassland-scrub-woodland mosaic and a distinctive
feature in the woodland flora is the occurrence of the rare coralroot (Cardamine bulbifera).
Additionally, the site contains extensive areas of semi-natural dry grassland and scrubland
facies on calcareous substrates (Festuca-Brometalia).
8.4.4
The same area of land is also nationally designated as a Site of Special Scientific Interest
(SSSI) and is referred to as Ashridge Common and Woods SSSI. This site receives the
SSSI designation on the basis that it comprises a mixture of ancient, semi-natural and
secondary woodland, plantation, scrub, a more open component dominated by bracken, and
grassland. The site supports an exceptionally rich breeding bird community including both
county and national rarities.
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8.4.5
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There is also a second SSSI located within the search area, namely Roughdown Common
SSSI, which is located 1.8km from the site boundary. This site comprises a small area of
unimproved calcareous grassland which supports a rich assemblage of plant species. There
are also two Local Nature Reserves (LNRs) within the search area. These are Shrubhill
Common and Howe Grove Wood LNR’s (located 1.5km and 0.95km respectively from the
site), both of which are designated as a result of their nature conservation and recreational
interest. The locations of these sites are shown in Appendix C.2 Figure 8.1.
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Local nature conservation sites
8.4.6
There are five non-statutory nature conservation sites located within 1km of the site
boundary. These are Local Wildlife Site (LWS), one of which is also an LNRs. Further
details of these are provided in Table 8.6.
Table 8.6: Non-statutory designated nature conservation sites
Grid
reference
Distance and
direction from
development site
Site Name
Type
Howe Grove
Wood
LWS
(and
LNR)
TL060087
950 m north-east
Ancient, semi-natural, coppiced woodland
with up to three different stand types,
representing a transition between
woodlands of the east and west of the
county. Selection Criteria: old secondary
woodland with a semi-natural character and
varied structure.
Paradise
Fields
LWS
TL060068
700 m south-east
A series of grassland fields which vary from
neutral to calcareous in character, with the
latter supporting the greatest species
diversity.
Gravel Hill
Spring Wood
LWS
TL045074
700 m west
An area of broad-leaved woodland bisected
by Gravel Hill Lane; a sunken green lane
with ancient remnants. Ancient woodland is
present to the south of the lane and old
secondary woodland to the north.
Disused
LWS
Railway Line,
Hemel
Hempstead
TL069088
800 m north-east
A dismantled railway route with banks
predominantly lined with old secondary
woodland and scrub. There are also small
areas of rough grassland and tall herb
vegetation.
Boxmoor
Common
TL040061
950 m south
A series of ancient grazing pastures,
situated on alluvial soils, alongside the River
Bulbourne, which support dry to marshy,
mostly semi-improved, neutral grassland.
Water voles (Arvicola amphibius) have been
recorded along the River Bulbourne.
8.4.7
LWS
Summary of Interest Features
The locations of the non-statutory nature conservations sites are shown in Appendix C.2
Figure 8.2.
Records of legally protected and priority species
8.4.8
There are no records of legally protected and/or priority species located on-site. However,
there are a number of records located within 1km of the site boundary. These records are
summarised below and a full list is provided in the Baseline Biodiversity Report located in
Appendix C.1.
8.4.9
Bats: There are a number of records of common pipistrelle bat (Pipistrellus pipistrellus) and
brown long-eared bat (Plecotus auritus) located within 1km of the site boundary. These date
from between (1991 and 2004). Furthermore, there are records of both of these species
roosting within 500m of the site boundary. The records of the roosts date from 2004 and are
appear to originate from approximately the same location.
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8.4.10
Water vole (Arvicola amphibius): There is a record of water vole (dating from 2000)
originating from approximately 400m north of the site boundary. Water vole has also been
recorded along the River Bulbourne.
8.4.11
UK BAP priority bird species recorded within 1km of the site are common bullfinch
(Pyrrhula pyrrhula) and European turtle dove (Streptopelia turtur). These records date from
2003.
8.4.12
Great crested newt: Having conducted a desk-based study, with the exception of the River
Gade, there are no waterbodies located on site or within 500m of the site boundary. The
river itself does not constitute suitable habitat to support great crested newt (Triturus
cristatus), therefore the potential presence of this species is not considered further within this
ES chapter.
Review of desk study information with reference to the River Gade
8.4.13
A full description of the River Gade in terms of its history, current WFD status, hydrology and
flooding, hydromorphological, biological and chemical data is provided within Section 2 of the
Water Framework Directive Assessment (see Appendix A.2).
8.4.14
The River Gade is a chalk stream, ephemeral in its upper reaches, which in its natural state
would exist as a small and shallow gravel-bed channel for most of its length. Upstream of
the development site in Gadebridge Park the current course of the river comprises a mill
race built in the 18th century. Downstream of the development site the River Gade channel
through Hemel Hempstead town centre (downstream of Combe Street to Moor End Road)
was modified in the late 1950s as part of the development of the new town oif Hemel
Hempstead to form the Water Gardens, which are now listed (Grade II). Within the
development site the course of the river has been modified at various times over the years
by the building of Leighton Buzzard Road, the existing West Herts College and the existing
Civic Centre.
8.4.15
The reach through the development site is poorer in terms of hydromorphological diversity
and ecology compared with the best sections of the river - as exemplified by samples
collected at Picott’s End. In particular, marginal vegetation through the site is currently
limited in diversity due to the mowing regime, which results in amenity grassland extending
right to the water’s edge, although there are some mature willow trees with extensive root
systems extending into the river and creating sheltered habitat. The channel is of relatively
uniform cross-section with a well-functioning chalk gravel substrate but low
hydrmorphological diversity.
8.4.16
The River Gade is classified as a salmonid water under the Freshwater Fish Directive 7.
Routine surveys by the Environment Agency show that the fish community is dominated by
brown trout (Salmo trutta) and pike (Esox lucius),
7
Directive 2006/44/EC of the European Parliament and of the Council of 6 September 2006 on the quality of fresh
waters needing protection or improvement in order to support fish life (codified version)
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8.4.17
Generally the River Gade in the vicinity complies with standards set for defining ‘moderate’
and in some places ‘good’ status under the Water Framework Directive, although it suffers
from elevated levels of nitrate and nitrite and fails the stringent nitrite standards set for
salmonid waters.
8.4.18
LIFE8 scores show that the biological community in the river shows some response to a lack
of water flow. This arises due to abstraction from the groundwater for public water supply.
8.4.19
Streams such as the River Gade that rise on chalk in southern England share a number of
hydrogeological, hydrological and ecological characteristics that, combined, allow the
recognition of a particular river type known as a ‘chalk stream’ or ‘chalk bourne’. These were
recognised as a priority habitat in the UK Biodiversity Action Plan, developed to implement
the Rio Convention, and protection has been carried forward in the definition of rivers as a
habitat of principal importance under s.41 of the Natural Environment and Rural
Communities Act 2006. Chalk streams of the Chilterns are recognised as part of the ‘rivers’
habitat defined under s.41 of this Act.
Survey results
Context and site description
8.4.20
The site is approximately 4 hectares (ha) in extent and is located within an urban area near
the centre of Hemel Hempstead. To the north of the site is Queensway, with buildings and
Gadebridge Park beyond, with the River Gade running through it. To the east of the site is
Marlowes and a shopping area. To the west is a narrow strip of amenity grassland and
scattered trees, with the Leighton Buzzard Road (A4146) and residential housing beyond.
To the south of the site are a number of public buildings which are surrounded by
hardstanding and amenity grassland.
8.4.21
The site comprises an open landscaped college campus, two civic centre buildings and a
Methodist church set within an urban area. The buildings are surrounded by amenity
grassland, hardstanding, ornamental hedgerow, planted borders and scattered trees. The
River Gade runs through the site from north to south.
8.4.22
Full details of survey methods and results are provided within Section 2 and the appendices
of the Water Framework Directive Assessment (see Appendix A.2).
Habitats
8.4.23
The River Gade varies in width throughout the length of the site from between 1-4m and at
the time of survey was approximately 0.2m in depth. The water was clear and fast flowing
with a gravel and silty substrate. The banks of the watercourse, which comprise amenity
grassland, are approximately 0.5m in height and are regularly managed via strimming or
mowing up to the edge of the channel. In places the banks are re-enforced by wooden
8
Lotic Invertebrate Flow Evaluation scores - a system for assessing the adequacy of the flow regime in
maintaining the expected macroinvertebrate fauna in rivers – described in: Extence C.A., Balbi D.M. & Chadd
R.P. (1999) River flow indexing using British benthic macroinvertebrates: a framework for setting hydroecologiocal
objectives. Regulated Rivers Research and Management, 15, 543-574.
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planks. At the time of the survey the watercourse contained little aquatic vegetation in the
upper sections, albeit there was a reasonably diverse assemblage of marginal species
towards the lower end of the reach. Aquatic and marginal vegetation was dominated by
water-cress (Rorippa nasturtium-aquaticum) with abundant introduced touch-me-not balsam
(Impatiens noli-tangere), occasional common reed (Phragmites australis) and yellow iris (Iris
pseudacorus), and occasional other common aquatic species. Some sections of the channel
were shaded by overhanging trees, such as weeping willow (Salix babylonica) and alder
(Alnus glutinosa).
8.4.24
The watercourse and buildings are set within areas of closely mown amenity grassland
comprising common grassland species, with occasional planted borders and ornamental
hedgerows, containing species such as ornamental roses (Rosa spp.), box (Buxus
sempervirens) and laurel (Prunus spp,), all of which are well maintained.
8.4.25
Standard trees are scattered throughout the site, particularly in the north. Species include
lime (Tilia spp.), sycamore (Acer pseudoplatanus), ash (Fraxinus excelsior), alder, cherry
(Prunus spp.), apple (Malus domestica), weeping willow, contorted willow (Salix babylonica
var.) and grey willow (Salix cinerea).
8.4.26
The majority of the buildings are classroom buildings of similar construction (Blocks A, B, C,
D, E, F, G, H and J) with a mixture of brick and metal cladding and glass windows (see
Target Note (TN) 9 on Appendix C.2 Figure 8.3 Phase 1 Habitat Map ). Building L is a
prefab style building (TN 10). All of these buildings have flat felted roofs. In the north-east
of the site is a single storey brick built storage building with two garage doors and a flat roof
(TN 10) and a small private bungalow with a pitched roof and a fenced-off garden (TN 11).
There are also a number of small buildings including a brick storage building which is
approximately 3m tall and 2m wide (TN 12).
8.4.27
The civic centre is located in the south of the site, along with various a concrete flat-roofed
buildings (e.g. TN 14).
8.4.28
Marlowe’s Methodist church is situated in the centre of the eastern boundary (TN 4). This
building is likely to be pre-1960 but appears to have been renovated and is in good repair;
however it was not possible to examine the building fully as access had not been agreed.
The church has a tiled, pitched roof. It is understood that the church is still in use, albeit the
western quarter appears to be a residence.
8.4.29
The distribution of terrestrial habitats is shown on the Phase 1 Habitat Map shown in
Appendix C.2 Figure 8.3. The target notes are provided in Appendix A in the Baseline
Biodiversity Report. River habitats are detailed in the results of the River Habitat Survey and
the River Corridor Survey described in the Water Framework Directive Assessment (see
Appendix A.2).
Species
8.4.30
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In addition to a variety of common and widespread species, the field surveys have identified
the presence/potential presence of the following legally protected or controlled, and/or
priority species on, over or adjacent to the site. It should be noted that the presence of other
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legally protected/priority species for example badger (Meles meles) and reptiles, has been
ruled out on the basis of the habitats present/absent and general urban setting of the site. A
more detailed rationale for this is discussed within the Baseline Biodiversity Report (See
Appendix C.1).
8.4.31
Bats: Buildings and tree inspections carried out in 2012 identified that the majority of the
buildings and trees located on site were not suitable to support roosting bats. However,
Marlowe’s Methodist Church does offer some potential to support a roost, albeit due to the
height of the building it was not possible to carry out detailed inspection work. As such,
survey work to determine the presence/absence of a roost was carried out in May/June
2013. This confirmed that bats were not utilising the church for their roosting requirements.
Additionally, the extended Phase 1 habitat survey identified that the River Gade and its
associated vegetation provide areas of suitable foraging habitat that could support
populations of bats originating from roosts in nearby residential houses. Bat activity surveys
identified that common pipistrelle bats forage in this part of the site. Furthermore, a single
fleeting noctule bat (Nyctalus noctula) call was also recorded during the surveys (albeit
thought that this bat was commuting over the site, rather than using the site for its habitat
requirements, so the potential presence of noctule bat is not considered further within this
report.). There was also one registration of a brown long-eared bat/ Myotis (the call was too
faint to clearly distinguish the species of bat, albeit there are records of brown long-eared bat
occurring within 1km). A few registrations of soprano pipistrelle bats were also recorded
during the June survey (foraging in the vicinity of Marlowes Church). All bats and their
roosts are legally protected and many bats are also priority species (see Baseline
Biodiversity Report Appendix C.1 for details of the legislation relevant to this group of
species).
8.4.32
Otter: During the otter survey, no evidence of otter was recorded from the section of the
River Gade contained within the development site boundary (nor to a distance of 50m
upstream and downstream). This said, the banks of the river within the site boundary had
been recently cut and disturbed, such that any evidence would have been difficult to detect.
Considering the habitat present on-site, the fact that the instance of otter within Hertfordshire
is increasing and that otter is known to occur in the River Gade more widely (beyond the
1km study area), even though there were no holts or laying up areas, it is likely that otters
periodically use this section of the river as they move through their territories. Otters and
their resting places are legally protected (see Baseline Biodiversity Report Appendix C.1 for
details of the legislation relevant to this species).
8.4.33
Priority and nesting bird species: The site provides habitat for a number of UK BAP
priority species, such as song thrush (Turdus philomelos) and house sparrow (Passer
domesticus), albeit due to the urban and built up nature of the site, the numbers of birds
present is likely to be reasonably small and not constitute an important population. All
nesting birds are legally protected (see Baseline Biodiversity Report Appendix C.1 for
details of the legislation relevant to this group of species).
8.4.34
Other priority species: The site provides a small amount of habitat that is suitable to
support populations of other priority species such as hedgehog (Erinaceus europaeus) and
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toad (Bufo bufo). Two hedgehogs were observed foraging in the grassland adjacent to the
River Gade during the bat surveys.
8.4.35
Aquatic invertebrate species: The River Gade provides habitat that is suitable to support
populations a few examples of priority aquatic invertebrate species but no rare or priority
species were recorded during the surveys.
8.4.36
Japanese knotweed (Fallopia japonica): There is a small clump of Japanese knotweed
located off-site, just upstream of the site boundary (TL053076). This is invasive species of
detriment to nature conservation.
8.4.37
Signal crayfish (Pacifastacus leniusculus): An abundance of signal crayfish was
observed within this section of the river. This is an invasive species of detriment to nature
conservation.
Future baseline
8.4.38
In the absence of the proposed development, it is likely that there would be little change in
the baseline conditions present at the site, on the basis that the habitats would continue to
be managed by the College.
Identification of receptors
8.4.39
Drawing upon the biological data assembled from both the desk study and field surveys, for
the purposes of this EIA, the potential receptors in relation to the proposed development are
listed in Table 8.7, together with the rationale for their inclusion, relating to biodiversity
conservation value and legal status. These have been valued on the scale very high, high,
medium and low, according to the criteria that are set out in Table 8.2.
Table 8.7: Potential receptors
Potential receptor
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Valuation/
sensitivity
Legal
protection/Policy
Rationale
Chiltern Beechwoods Very high
SAC
Off-site statutory
SACs are of international importance as a
designated site
result of the Annex I habitats that they
Habitats Regulations support.
2010
Ashridge Common
High
and Woods SSSI and
Roughdown
Common SSSI,
Off-site statutory
designated site
Wildlife and
Countryside Act
1981
SSSIs are of importance as a result of the
assemblages of flora and fauna that they
contain, which are important at a national
level
Shrubhill Common
Medium
and Howe Grove
Wood LNR, Howe
Grove Wood LWS,
Paradise Fields
LWS, Gravel Hill
Spring Wood LWS,
Disused Railway Line
LWS, Boxmoor
Common LWS
Off-site statutory
designated Local
Nature Reserve.
Off-site nonstatutory designated
sites
Local Development
Framework
The LNR and LWSs are of importance as
a result of the assemblages of flora and
fauna that they contain, which are
important at a local level.
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Potential receptor
Valuation/
sensitivity
Rationale
The River Gade
chalk river
High
UK, Hertfordshire
Biodiversity conservation value (was a
BAP priority habitats BPA priority habitat) and rarity in a
European context
Mature standard
trees
Medium
Tree preservation
orders
The cumulative cover of mature standard
trees on site is important at local level. A
number of these trees are also covered by
TPOs.
Common pipistrelle
bat
Medium
Wildlife and
Countryside Act
1981
Habitats Regulations
2010
Common pipistrelle bats are reasonably
common in Hertfordshire albeit they are
still of biodiversity conservation value.
They are also legally protected. The
number of bats recorded utilising the site
was relatively small, such that this
population is assessed as being of
medium value for nature conservation.
Soprano pipistrelle
bat
Medium
UK BAP priority
species
Wildlife and
Countryside Act
1981
Habitats Regulations
2010
Soprano pipistrelle bats are reasonably
common in Hertfordshire albeit they are
still of biodiversity conservation value.
They are also legally protected. The
number of bats recorded utilising the site
was relatively small, such that this
population is assessed as being of
medium value for nature conservation.
Brown long-eared bat Medium
UK BAP priority
species
Wildlife and
Countryside Act
1981
Habitats Regulations
2010
Brown long-eared bats are of biodiversity
conservation value. They are also legally
protected. There was only one potential
brown long-eared bat registration recorded
during the survey and considering the
habitats present on site, the number of
brown long-eared bats utilising the site is
likely to be relatively small. As such, this
population is assessed as being of
medium value for nature conservation.
Otter
High
UK and
Hertfordshire BAP
priority species
Wildlife and
Countryside Act
1981
Habitats Regulations
2010
Although otters are known to occur more
widely in the River Gade and are on the
increase in Hertfordshire as a whole, they
are still sufficiently rare that they are
considered to be of high value for nature
conservation. . They are also legally
protected.
Priority birds
Medium
UK BAP priority
species
Wildlife and
Countryside Act
1981
Populations of priority bird species such
as bullfinch and European turtle dove, are
assessed as being of medium value for
biodiversity conservation value as a result
of their recent declining populations. They
are also legally protected.
All nesting birds
Low
Wildlife and
Countryside Act
1981
All nesting birds are legally protected.
UK BAP priority
species
Hedgehogs are assessed as being of
medium value for biodiversity conservation
value as a result of their recent declining
population.
Other priority species Medium
e.g. hedgehogs
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protection/Policy
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Potential effects
8.5.1
This section describes the potential effects on valued ecological receptors in the absence of
the mitigation measures and scheme enhancements to be incorporated into the scheme.
These effects are separated into those effects that will occur during the construction and
operational phases of development.
Construction phase
8.5.2
The construction phase will comprise a demolition phase, earthmoving and building. River
realignment will need to take place early in the process, as soon as relevant buildings have
been demolished and the ground cleared. The old river channels will not be infilled until the
new channels have been watered and shown to hold water. Further details are given in
section 4 of this ES and in the section 3 of the Water Framework Directive Assessment (see
Appendix A.2).
8.5.3
Potential temporary adverse effects on the Chiltern Beechwood SAC (off-site statutory
nature conservation site) could arise through temporary increased levels of dust and an
increased risk of pollution incident, which could damage the sensitive vegetation
communities for which the site is designated. This SAC is of international importance for
nature conservation and is designated as a result of the Annex I vegetation communities that
it supports i.e. the presence of an extensive tract of Asperulo-Fagetum beech forests and
semi-natural dry grassland.
8.5.4
Potential temporary adverse effects on Ashridge Common and Woods SSSI, Roughdown
Common SSSI, Shrubhill Common LNR and Howe Grove Wood LNR could arise through
temporary increased levels of dust, noise and an increased risk of pollution incident during
the construction phase, which could damage the sensitive vegetation communities and/or
disturb the sensitive bird communities, for which these sites are designated.
8.5.5
Potential temporary adverse effects on Howe Grove Wood LWS, Paradise Fields LWS,
Gravel Hill Spring Wood, Disused Railway Line LWS and Boxmoor Common LWS could
arise through temporary increased levels of dust and an increased risk of pollution incident,
which could damage the sensitive vegetation communities for which these sites are primarily
designated.
8.5.6
Potential temporary adverse effects on the River Gade (both upstream and downstream of
the site) could arise through increased levels of dust, increased levels of sediment and
polluted run-off which could enter the watercourse and an increased risk of pollution incident
during the construction phase, all of which could damage the sensitive in-river and riparian
communities that the river supports.
8.5.7
Potential adverse effects could be caused to the River Gade through loss of riverine and
riparian habitat resulting from the diversion of the river.
8.5.8
The permanent loss of mature standard trees during the construction phase of the
development may represent an adverse effect.
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8.5.9
Potential temporary adverse effects on otter could arise through increased levels of light,
noise, risk of pollution incident and human disturbance during the construction phase.
8.5.10
Potential temporary adverse effects on otter could arise through construction work to divert
the River Gade, resulting in disruption to otter movements.
8.5.11
Potential temporary adverse effects on foraging bats could arise through increased levels of
light and noise during the construction phase and light only during the operational phase.
8.5.12
Potential temporary adverse effects on foraging bats could arise through temporary loss of
habitat during the construction phase.
8.5.13
Potential temporary adverse effects on populations of priority bird species could arise
through increased levels of light, noise and human disturbance the construction phase.
8.5.14
Potential temporary adverse effects on populations of priority bird species could arise
through temporary habitat loss (i.e. loss of potential foraging habitat and nesting sites) during
the construction phase.
8.5.15
Potential adverse effects on populations of other priority species, e.g. hedgehog and toad,
could arise through increased levels of light, noise and human disturbance during the
construction phase.
Operation phase
8.5.16
Potential temporary adverse effects on the ecology of the river could arise as a result of the
time taken for aquatic ecology representative of chalk streams to become established in the
diverted river channel.
8.5.17
There is potential for the fully established new river channel to show an improvement in
ecological diversity compared with the existing situation.
8.5.18
Potential permanent adverse effects on the ecology of the river corridor could arise through
loss of flow in the river to the groundwater.
8.5.19
Potential permanent adverse effects on the ecology of the river corridor could arise through
the presence of a new low bridge or culvert over the river.
8.5.20
Potential permanent adverse effects on the ecology of the river corridor could arise through
increased levels of lighting during the operational phases.
8.5.21
Overall adverse effects on the River Ecology could affect compliance with the Water
Framework Directive (see Appendix A.2).
8.5.22
Potential permanent adverse effects on otter could arise through increased levels of light and
human disturbance during the operational phase.
8.5.23
Potential permanent adverse effects on foraging bats could arise through increased levels of
lighting during the operational phase.
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8.5.24
Potential permanent adverse effects on populations of priority bird species could arise
through increased levels of light and human disturbance during the operational phase.
8.5.25
Potential permanent adverse effects on populations of other priority species e.g. hedgehog
and toad, could arise through increased levels of light and human disturbance during the
operational phase.
Environmental measures and mitigation
8.6.1
The proposed development incorporates a number of measures designed to avoid, minimise
or mitigate effects on biodiversity and ensure compliance with relevant legislation. In
addition, the proposed development includes measures to enhance biodiversity, as required
by the National Planning Policy Framework (March 2012). The measures included are
summarised in Table 8.8. Where appropriate enhancement measures incorporated within
the scheme are illustrated in Appendix C.2 Figure 8.4.
8.6.2
For the River Gade, additional details are given in the Water Framework Directive
Assessment (see Appendix A.2).
Table 8.8
Potential receptors
Environmental measures and mitigation incorporated into the scheme design
Potential changes and effects
Off-site statutory and nature
conservation sites, Chiltern
Beechwood SAC, Ashridge
Common and Woods SSSI,
Roughdown Common SSSI,
Shrubhill Common LNR,
Howe Wood Grove LNR
Increased levels of dust, noise
and pollution from construction
works could damage sensitive
flora and disturb sensitive bird
communities within the
designated sites.
River Gade
Increased levels of dust and
pollution from construction
works could damage sensitive
riparian communities that the
river supports
Incorporated measure
Standard pollution prevention measures, as
outlined in the Environment Agency’s Pollution
Prevention Guidelines9, will be implemented
during the construction phase of the
development.
Noise abatement strategy to be included within
the scheme design.
Adverse effects on downsteam
ecology during construction,
due to release of dust,
pollutants, turbidity or loss of
flow.
Standard pollution prevention measures, as
outlined in the Environment Agency’s Pollution
Prevention Guidelines, will be implemented
during the construction phase of the
development.
New diversion channel be designed to replicate
river substrate in existing best sections of River
Gade.
Sampling of soil conditions in new channel for
contaminants before watering (see also section
9).
Temporary loss of river and
riparian habitat, to be replaced New channels to incorporate enhanced habitat
and enhanced by new diversion diversity resulting in the long term in a more
channel.
diverse in-river and riparian ecology.
9
The Environment Agency and SEPA (Scottish Environment Protection Agency). Guidelines relevant to this work
would include, PPG1 (general), PPG2 (on-site oil storage), PPG5 (work near watercourses) and PPG6
(construction activities).
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Potential receptors
River Gade (continued)
Potential changes and effects
Loss of flow from the river
channel affecting on-site and
downstream reaches.
Additional boards in place at surface water
culvert entry (already done) to minimize losses to
culvert at low flows.
Adverse effects on river
organisms of new bridge.
Ensure normal river substrate continues through
bridge.
Obstruction of river corridor by
new bridge.
Provide space under bridge on east side for
passage of non-aquatic mammals.
Effects of increased light in the
river corridor.
Design lighting to ensure intrinsically dark
conditions maintained. Turn lights off in car park
and petrol station areas at night.
Adverse effects on Water
Framework Directive
compliance.
Mature standard trees
Incorporated measure
Combined effects of all measures.
Direct loss of 47 mature
standard trees some of which
are covered by TPOs.
Trees to be retained wherever possible. Those
trees to be retained should be done so with
reference to BS 5837- Trees in relation to design,
demolition and construction.
New trees and scrub (over an area of 0.17ha) to
be planted, increasing the coverage of trees and
scrub across the site. These will comprise native
species of local origin and be similar to those
species already found on site, e.g. willows and
poplars.
Otter
Disturbance to otter through
permanent diversion of the
river, as well as increased
levels of noise, light and human
disturbance during the
construction phase and
increased levels of light and
human disturbance during the
operation phase
Standard pollution prevention measures, as
outlined in the Environment Agency’s Pollution
Prevention Guidelines, will be implemented
during the construction phase of the
development.
No night time working will be permitted
throughout the duration of the construction
phase.
A light and noise abatement strategy will be
included within the scheme design to incorporate
directional lighting and ensure that the river and
riparian habitat remain intrinsically dark. This will
include turning off site lights at night.
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Potential receptors
Foraging bats
Potential changes and effects
Permanent loss of existing river
habitat and some of the trees
that provide foraging and
commuting habitat for bats from
nearby roosts, to be replaced by
an enhanced channel and
associated riparian habitat.
Incorporated measure
Increased provision of tree and scrub planting
(0.17ha) and the creation of a species-rich
marshy area of grassland (0.27ha), set within a
mosaic of other habitats, providing an optimal
foraging resource for bats from nearby roosts.
Standard pollution prevention measures, as
outlined in the Environment Agency’s Pollution
Disturbance to foraging bats
Prevention Guidelines9, will be implemented
through increased levels of light during the construction phase of the
and noise during the
development. This will also include a noise
abatement strategy.
construction phase and light
only during the operational
phases.
A low level lighting strategy and noise abatement
strategy is to be incorporated within the proposed
scheme design, to minimise light pollution during
both the construction and operational phases
and noise during the construction phase.
Priority/nesting birds
Disturbance to breeding birds
during the construction phase.
Increased risk of contravening
the legislation relevant to
breeding birds.
No vegetation or buildings which provide
potential habitat for breeding birds will be
removed /demolished during bird breeding
season (i.e. avoiding end of February-July
inclusive). Alternatively if this is not possible,
vegetation/potential nesting areas on buildings
would need to be checked by an ecological clerk
of works prior to its removal. If nesting birds are
found, works within the immediate vicinity of the
nest would need to be delayed until the young
have fledged.
Enhanced provision of optimal habitat for birds,
through the provision of a small area of speciesrich marshy grassland (0.27ha), increased
provision of trees and scrub (0.17ha) (set within
a mosaic of other habitat types) and the
installation of 20 bird boxes around the site.
Scheme enhancements
River Gade
Improved habitat diversity
Additional morphological features including
gravel bars, improved bank profiles, off-line
Improved marginal communities wetlands, two-stage channel, large woody debris
and refuge areas to be incorporated into the
diversion channels.
8m buffer strip along both banks
with no built development
Bankside planting and maintenance regime
except proposed riverside
improved to increase diversity of emergent
footpath and cycleway.
species.
Landscaping planting to ensure that east bank of
the diverted river remains inaccessible to people
and provides cover for movement of wildlife.
Offline wetlands created to increase aquatic
habitat diversity.
Hedgerow
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Additional provision of
hedgerow habitat
Creation of 0.5km of species-rich hedgerow
comprising native species of local origin.
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Potential receptors
Potential changes and effects
Incorporated measure
Invertebrates
Additional provision of habitat
for invertebrates - will also
provide improved foraging for
bats.
Additional provision of geomorphological features
within the river channel to provide a diverse
habitat for aquatic invertebrates. Furthermore
log piles and pyramids to be provided within an
area of species-rich marshy grassland to provide
habitat for invertebrates during their terrestrial life
stages.
Otter
Additional provision of habitat
for otter
Creation of laying up areas and longer riparian
vegetation to provide cover, laying up areas and
foraging opportunities for otter.
Roosting bats
Additional provision of roosting
bats
Additional roosting sites for bats will be provided
within the scheme design. Bat tiles and bat
bricks will be incorporated within new buildings to
permit access to the roof spaces of new
buildings. 30 bat boxes will also be installed on
buildings/ mature trees retained within the site,
where appropriate. These will comprise a
mixture of Schweggler 1FF and Kent bat boxes.
8.6.3
A habitat creation/enhancement and management plan detailing the environmental
measures to be incorporated within the development design will be written by a suitably
qualified ecologist. This will provide a detailed specification of the habitats to be created,
together with a programme of work.
Residual effects
Construction phase
8.7.1
The following section evaluates the residual effects on each of the receptors after mitigation
and enhancement measures have been incorporated within the scheme.
8.7.2
Potential temporary adverse effects on the Chiltern Beechwood SAC (off-site statutory
nature conservation site) arising through temporary increased levels of dust and an
increased risk of pollution incident, which could damage the sensitive vegetation
communities for which the site is designated. The SAC is situated 5.58 km from the site
boundary and is separated from it by roads and extensive areas of residential properties and
agricultural land. It is not hydrologically linked to the proposed development site. As such,
considering the relatively small scale of the development, the distant location of the SAC
from the development site, together with the standard pollution prevention measures to be
incorporated within the CEMP, the proposed development will not result in any measureable
effects on the sensitive vegetation communities for which the SAC is designated. On this
basis the residual effects are assessed as being negligible, despite the very high value of the
site.
8.7.3
Potential temporary adverse effects on Ashridge Common and Woods SSSI, Roughdown
Common SSSI, Shrubhill Common LNR and Howe Grove Wood LNR arising through
temporary increased levels of dust and an increased risk of pollution incident during the
construction phase, which could damage the sensitive vegetation communities for which
these sites are designated. Increased levels of noise during the construction phase could
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also disturb the breeding birds present at these sites. All of these sites are located in excess
of 0.95km from the site boundary, and are separated from it by infrastructure, residential and
agricultural land. None of the sites is hydrologically linked to the proposed development site.
Considering the relatively small scale of the development, the distant location of these sites
from the development site, together with the standard pollution prevention and noise
abatement measures to be incorporated within the CEMP, the proposed development will
not result in any measureable adverse effects on the sensitive vegetation communities or the
breeding bird communities for which the SSSIs and LNRs are designated. On this basis the
residual effects are assessed as being negligible, despite the high value of the site.
8.7.4
Potential temporary adverse effects on Howe Grove Wood LWS, Paradise Fields LWS,
Gravel Hill Spring Wood, Disused Railway Line LWS and Boxmoor Common LWS arising
through the temporary increased risk of pollution incident and levels of dust during the
construction phase damaging the sensitive vegetation communities for which these sites are
designated. All of these sites are designated as a result of the woodland and grassland
communities that they support. Furthermore, they are situated in excess 0.7km from the site
boundary and are separated from it by roads and extensive areas of residential properties.
None of the sites is hydrologically linked to the proposed development site. Considering the
relatively small scale of the development, the distant location of these sites from the
development site, together with the standard pollution prevention measures to be
incorporated within the CEMP, the proposed development will not result in any measureable
adverse effects on the vegetation communities for which these sites are designated and the
residual effects are assessed as being negligible.
8.7.5
Potential temporary adverse effects on the River Gade (both upstream and downstream of
the site) arising through increased levels of dust, increased levels of sediment and polluted
run-off which could enter the watercourse, and an increased risk of pollution incident during
the construction phase, all of which could damage the sensitive aquatic and riparian
communities that the river supports. These aspects are considered in the Water Framework
Directive Assessment (in Appendix A.2). Implementation of mitigation summarised in Table
8.8 will ensure that effects on the River Gade are very low in magnitude, leading to an
overall impact assessment on this high value receptor of minor adverse.
8.7.6
Potential adverse effects on the River Gade through loss of riverine and riparian habitat
resulting from the diversion of the river. The proposed development will result in the
permanent loss of a section of the River Gade measuring 250m and its associated riparian
habitat, resulting from the diversion. Although a new section of river habitat is to be created,
(see Appendix C.2 Figure 8.5) the construction period will extend between winter 2013 and
winter 2014, and as such there will be a period during the construction and afterwards (whilst
the new river system establishes), when the new river will not provide the same quality of
aquatic and riparian habitat as that which is in existence currently. The existing channel will
be replaced by a new channel designed as described in the Water Framework Directive
Assessment (in Appendix A.2) and incorporating the mitigation and enhancement measures
summarised in Table 8.8, such that this effect will be temporary during the construction
period but moderate adverse.
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8.7.7
Potential permanent loss of 47 mature standard trees during the construction phases of the
proposed development. This will be mitigated as described in Table 8.8. Although the
enhancement measures will partially mitigate the loss of mature trees, due to the reasonably
limited extent of additional tree planting, together with the lengthy period that these trees will
take to establish and mature, adverse effects associated with the loss of mature standard
trees on site are assessed as being moderate adverse in the short term. The extent of this
adverse effect will lessen in the long term to minor adverse.
8.7.8
Potential adverse effects on otter arising through increased level of light, noise, risk of
pollution and human disturbance during the construction phase. Although no firm evidence
is available, it was concluded in the baseline study that otters are likely to pass through the
site. However, use is anticipated to be at a very low level and with the avoidance and
mitigation measures listed in Table 8.8 in place residual effects on otter arising as a result of
construction of the proposed development are assessed as being negligible.
8.7.9
Potential temporary adverse effects on otter arising through construction work to divert the
River Gade, resulting in temporary loss of habitat and disruption to otter movements. As
explained above, otter use is expected to be at a very low level and the river corridor will be
maintained in some form throughout, so there should be no obstruction to otter movement
when work is stopped overnight. Therefore, impacts on otter movements arising as a result
of construction of the proposed development are assessed as being minor adverse.
8.7.10
Potential adverse effects on foraging bats arising through temporary loss of foraging habitat
during the construction phase. Brown long-eared bats, common pipistrelle bats and soprano
pipistrelle bats have been recorded on site and within 1km of the site boundary. Foraging
surveys carried out in May/June 2013 determined that the majority of the site offers little
foraging habitat, with the exception of the river corridor which provides both optimal foraging
and commuting habitat for common pipistrelle and (potentially) brown long-eared bats
originating from nearby roosts. However, considering the provision of other parkland areas
within the vicinity of the site, the development site is not considered to represent an
important foraging resource. This assertion is supported by the relatively low levels of bat
activity recorded during the activity surveys. Since the loss of foraging habitat is only to be
temporary, there are extensive areas of foraging habitat to the north of the site and that the
new areas of river habitat will represent an enhancement on that which is currently present,
there will be no significant adverse effects on any potential population of foraging bat species
arising as a result of the construction of the proposed development and impacts are
assessed as negligible.
8.7.11
Potential adverse effects on foraging bats arising through increased levels of light and noise
during the construction phase. Noise and light and abatement strategies will be incorporated
within the CEMP. This will detail the requirement for no night time working during the
construction phase. As such, residual effects on foraging bats as a result of increased levels
of light or noise during the construction phase are assessed as being negligible.
8.7.12
Potential temporary adverse effects on populations of priority and nesting bird species
through temporary loss of habitat. The site has the potential to support priority bird species
such as song thrush as well as nesting common bird species. Due to the nature and limited
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extent of the habitats present on site, any potential population of priority bird species is likely
to be limited to only single breeding pairs or a very low number of such species. Subject to
implementation of avoidance measures detailed in Table 8.8, residual adverse effects
associated with construction will be minor adverse but temporary.
8.7.13
Potential temporary adverse effects on populations of nesting bird species through increased
risk of contravention of the legislation: To avoid contravention of the Wildlife and Countryside
Act 1981 (as amended) in relation to disturbance of breeding birds, removal of
vegetation/buildings/structures that may support active nests will only take place outside the
bird breeding season or if surveys have confirmed that no birds are breeding in the areas to
be lost. In view of the timing restrictions or additional supervision of vegetation removal,
residual effects are assessed as being negligible.
8.7.14
Potential adverse effects on other priority species through temporary loss of habitat: Part of
the site comprises the River Gade which provides habitat for other priority species (e.g.
common toad and hedgehog). Bearing mind that, while the habitat will be disturbed
temporarily, a river corridor will be maintained throughout, adverse effects on any potential
populations of other priority species that may occur on site will be temporary and have been
assessed as minor adverse.
Operational phase
8.7.15
Potential temporary adverse effects on the River Gade could arise as a result of the time
taken for aquatic ecology representative of chalk streams to become established in the
diverted river channel. The process to be adopted in terms of creation and watering of the
new channels (see the Water Framework Directive Assessment in Appendix A.2) will assist
in minimising the time taken to establish new river communities and many biological
elements will establish fairly rapidly (weeks to months), although full development will take
longer. This represents a moderate adverse but temporary impact.
8.7.16
There is potential for the fully established new river channel to show an improvement in
ecological diversity compared with the existing situation. In the longer term this should be
achieved by the design proposed in the Water Framework Directive Assessment (see
Appendix A.2). This would represent a minor to moderate beneficial impact.
8.7.17
Potential permanent adverse effects on the aquatic and riparian communities of the River
Gade that could arise through loss of flow in the river to the groundwater. As discussed in
the Water Framework Directive Assessment (in Appendix A.2) and summarised in Table
8.8, steps have already been taken to minimise loss of flow to the surface water culvert in
dry periods. New channels will be tested and reasonable sealing achieved before they are
put into use. With these measures in place, additional water losses should be very low
giving a possible minor adverse impact at worst. Any impact will be temporary until the
channel reaches equilibrium.
8.7.18
Potential permanent adverse effects on the aquatic and riparian communities could arise
through the presence of a new low bridge or culvert over the river. As discussed in the
Water Framework Directive Assessment (in Appendix A.2) and summarised in Table 8.8,
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obstruction of mammal passage along the river bank will be avoided by providing a route
under the bridge and the river substrate will be continued under the bridge. Effects on the
river as a whole will be very low, giving a minor adverse effect assessment result.
8.7.19
Potential permanent adverse effects on the aquatic and riparian communities of the River
Gade could arise through increased levels of lighting during the operational phases. With
proposed mitigation in place, luminance levels in the river corridor will be no higher than they
are at present, possibly lower, so effects will be negligible or possibly minor beneficial.
8.7.20
Overall adverse effects on the aquatic and riparian communities of the River Gade could
compromise compliance with the Water Framework Directive (WFD). The Water Framework
Directive Assessment (see Appendix A.2) explains how the scheme has been designed to
avoid adverse impacts on the status of any quality element assessed under the Directive and
to provide benefit where possible. The scheme will result in no deterioration in or hindrance
to meeting WFD targets.
8.7.21
Potential adverse effects on otter arising through increased level of light and human
disturbance during the operational phase. The newly constructed section of watercourse
and associated habitats will not be lit (so as to reduce disturbance to otter once the site is
operational). Less accessible areas will be created along the new channel (via scrub
planting) to provide quiet areas for otter. As a result of the mitigation measures that are to
be incorporated within the scheme design, residual effects on otter arising as a result
increased levels of light and human disturbance are assessed as being negligible.
8.7.22
Potential adverse effects on foraging bats arising through increased levels of light during the
operational phase. Where areas are to be lit, this will be achieved through the installation of
directional lighting, whilst the new channel and associated riparian vegetation will not be lit at
all. In view of this, any residual effects on foraging bats as a result of increased levels of
light are assessed as being negligible.
8.7.23
Potential permanent beneficial effects on foraging bats through provision of optimal foraging
and commuting habitat for bats, to include tree and scrub planting, the creation of a speciesrich area of marshy grassland and provision of log piles to encourage invertebrate species.
These will result in a minor beneficial effect.
8.7.24
Potential permanent beneficial effects through increased provision of bat roosting habitat on
site:
No bat roosting habitat will be lost to the proposed development; however
enhancement measures will include the provision of new roosts within the scheme design as
set out in Table 8.8. Furthermore, bat tiles and bat bricks will be installed in new structures,
facing outwards onto the areas of existing vegetation. In view of the enhancement measures
to be included within the scheme design, residual effects are assessed as being minor
beneficial.
8.7.25
Potential effects on populations of priority and nesting bird species. Enhancement measures
in respect of birds include the additional planting of trees and scrub, the creation of marshy
grassland areas and the installation of 20 bird boxes on site, enhancing the provision of both
foraging resources and nesting opportunities available. In view of this, residual effects
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associated with the enhanced provision of bird habitat on site are assessed as being minor
beneficial.
8.7.26
Potential adverse effects on other priority species through temporary loss of habitat: Part of
the site comprises the River Gade which provides habitat for other priority species (e.g.
common toad and hedgehog). The additional habitat creation measures i.e. tree planting,
creation of marshy species-rich grassland and the incorporation of log piles, will more than
compensate for the temporary loss of habitat and will likely result in beneficial effects on the
populations of other priority species, such that residual effects are assessed as being minor
beneficial.
8.7.27
Provision of 500m of new, species rich hedgerow will represent a permanent, minor
beneficial effect.
8.7.28
Table 8.9 provides a summary of residual effects.
Table 8.9
Summary of residual biodiversity effects and evaluation of their significance
Receptor & potential effect
Mitigation and site enhancements
Residual effects
and significance
Construction phase
Off-site statutory sites – temporary effects through
Noise abatement strategy and
increased levels of dust deposition, noise and
pollution prevention measures
included within the scheme design
increased risk of pollution incident during the
construction phase, that could damage the sensitive
vegetation and/or bird communities present within
the statutory sites
Temporary
Negligible
Not significant
Off-site non-statutory sites – temporary effects
through increased levels of dust deposition and an
increased risk of pollution incident
Pollution prevention measures
included within the scheme design
Temporary
Negligible
Not significant
River Gade- temporary effects arising through
Pollution prevention measures
increased levels of dust deposition, increased levels included within the scheme design
of sediment and polluted run-off which could enter
the watercourse, and an increased risk of pollution
incident during the construction phase, all of which
could damage the sensitive riparian communities
that the river supports both upstream and
downstream of the site
Temporary
Minor adverse
Not significant
River Gade - loss of riverine and riparian habitat
resulting from the diversion of the river.
New channel to be provided, with
Temporary
ecological enhancements. Measures Moderate adverse
to assist rapid establishment of chalk Significant
stream ecology in new channels
Mature standard trees – permanent loss of standard Additional planting of 47 ha of trees
trees
on-site
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Moderate adverse
reducing to minor
adverse over time
Significant for a
limited period
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Residual effects
and significance
Receptor & potential effect
Mitigation and site enhancements
Otter – effects through increased levels of light,
noise and human disturbance during the
construction phases
Pollution prevention measures
included within the scheme design.
No night time working during the
construction phase.
A noise and light abatement strategy
is to be included within the scheme
design.
Temporary
Negligible
Not significant
Otter – disruption to movement through territories,
as a result of river diversion works
No night time working.
Temporary
Minor adverse
Not significant
Bats – loss of potential foraging areas
No night time working.
Temporary
Negligible
Not significant
Bats – effects through increased levels of light and
noise disturbance during the construction phase
No night time working during the
construction phase.
A noise and light abatement strategy
is to be included within the scheme
design.
Temporary
Negligible
Not significant
Removal of vegetation/buildings/
structures that may support active
nests will only take place outside the
bird-breeding season or if surveys
Breeding bird assemblage - increased risk of
have confirmed that no birds are
contravening the legislation relevant to nesting birds breeding in the areas to be lost
Temporary
Minor adverse
Not significant
Other priority species – temporary loss of habitat
Temporary
Minor adverse
Not significant
Priority/ nesting bird assemblage - temporary loss
of habitat
None
Temporary
Negligible
Not significant
Operational phase
River Gade - effects on the auqtic and riparian
River design and construction/
communities could arise as a result of the time taken watering methodology
for aquatic ecology representative of chalk streams
to become established in the diverted river channel.
Temporary
Moderate adverse
Significant
River Gade – new river channel potential for
ecological benefit
Creation of new diverse section of
watercourse
Permanent
Minor Beneficial
Not significant
River Gade - effects on water availability of possible
loss of flow in the river to the groundwater
Raise weir boards (done).
Temporary
Watering procedure for new channels Minor adverse
Not significant
River Gade - presence of low bridge or culvert
Maintain river substrate under bridge. Permanent
Minor adverse
Ensure passage available for
mammals under bridge
Not significant
River Gade - increased light levels
Maintain or reduce existing levels.
Permanent
Negligible to minor
beneficial
Not significant
River Gade - compromised compliance with Water
Framework Directive
Scheme designed so as not to affect
status of WFD quality elements
Permanent
Negligible
Not significant
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Receptor & potential effect
Mitigation and site enhancements
Residual effects
and significance
Otter – effects of increased levels of light and
human disturbance
Low levels of light along river, lights
turned off at night
Undisturbed east bank with cover
Permanent
Negligible
Not significant
Bats – effects through increased levels of light
The new section of channel will not
be lit. Furthermore, directional
lighting will be installed in other parts
of the site.
Permanent
Negligible
Not significant
Bats –provision of foraging habitat
Tree and scrub planting, creation of a Permanent
species-rich area of marshy
Minor beneficial
grassland, provision of log piles
Not significant
Bats – additional provision of roosting habitat
Additional provision of 30 bat boxes
Permanent
around the site and installation of bat Minor beneficial
bricks and bat tiles within new
Not significant
buildings where appropriate.
Priority/nesting bird assemblage - enhancement of
habitat
Enhanced provision of suitable
Permanent
habitat for breeding birds via tree
Minor beneficial
planting and the creation of an area
Not significant
of species-rich marshy grassland and
scrub. 20 bird nesting boxes also to
be installed on and around site.
Other priority species – improved habitat
Enhanced provision of suitable
Permanent
habitat for other priority species such Minor beneficial
as hedgehog via tree and scrub
Not significant
planting and the creation of an area
of species-rich marshy grassland and
log piles.
Species-rich hedgerow – Increased provision
Additional planting of 0.5 km of
species-rich hedgerow
Permanent
Minor beneficial
Not significant
Summary
8.8.1
A desk study identified the following statutory nature conservation sites occuring within
10km10 and 5km of the development site boundary: the Chiltern Beechwoods Special Area of
Conservation (SAC), Ashridge Common and Woods Special Site of Scientific Interest
(SSSI), Rough Down Common SSSI and Shrubhill Common and Howe Grove Wood Local
Nature Reserve (LNR). The SAC designation is a European level designation for nature
conservation, whilst the SSSI and LNR are both nationally important designations.
Furthermore, there are five non-statutory nature conservation sites located off-site but within
the 1km search area.
8.8.2
The proposed development site comprises an open, landscaped college campus, two civic
centre buildings and a church. The buildings are surrounded by amenity grassland,
hardstanding, planted borders and scattered trees. The River Gade, a small chalk river, also
runs through the site from north to south. This supports a reasonably diverse assemblage of
marginal species towards the lower end of the reach, albeit the upper part of the reach has
10
The search are is extended to 10km from the site boundary for sites of international importance and 5km from the site
boundary for sites of national importance.
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been subject to recent management. The river channel functions well as a chalk stream but
has limited diversity of in-stream habitat types. The river is fringed by a number of mature
trees, mostly willow, poplar and sycamore.
8.8.3
Valued habitats located on site or within the development’s potential zone of influence
include in particular the River Gade and its riparian vegetation and the collective coverage of
mature standard trees, some of which are covered by TPOs.
8.8.4
There are no records of legally protected and/or priority species on site but the following
species have been recorded within 1km of the site boundary and/or have the potential to
occur on site:

common pipistrelle bat;

soprano pipistrelle bat;

brown long-eared bat;

otter;

water vole;

priority bird species: common bullfinch and European turtle dove; and

other priority species: hedgehog and common toad.
8.8.5
The proposed development will result in the permanent loss of a section of the River Gade
measuring 250m and its associated riparian habitat, resulting from diversion of the river.
Although a new section of river habitat is to be created, there will be a period, lasting 12
months (whilst the new river system establishes) whereby the new river will not provide the
same quality of aquatic and riparian habitat as that which is in existence currently. Similarly,
mature trees that require removal will be replaced by replanting but there will be a time-lag
before the new trees reach maturity. The reduction in river habitat quality and the temporary
loss of mature tree habitat are the only impacts identified that were assessed as significant
(impacts rated as moderate adverse), albeit they will be temporary and lessen in the long
term.
8.8.6
All other potential impacts were assessed as negligible or minor (some adverse and some
beneficial) once mitigation and enhancement measures had been incorporated.
8.8.7
Survey work to determine the presence/absence of roosting bats in the Methodist Church
was carried out in May/June 2013. This confirmed the absence of any roosts within the
church, albeit a number of common pipistrelle bats, soprano pipistrelle bats and a (potential)
brown long-eared bat were recorded foraging in the vicinity of the River Gade during the bat
activity surveys. As an enhancement measure, the provision of new roosts will be
incorporated within the scheme design. This will include the provision of 30 bat boxes to be
installed on the existing, retained mature trees and new buildings located on site.
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Furthermore, bat tiles and bat bricks will be installed in new structures, facing outwards on to
the areas of existing vegetation.
8.8.8
Overall, environmental mitigation and enhancement measures incorporated within the
proposed scheme design include:

the additional planting of 0.17ha of broad-leaved trees and scrub;

the creation of 0.27ha of species-rich marshy grassland;

increasing the habitat diversity within the diverted river channel compared with the
existing channel by including features such as gravel bars, improved bank profiles, offline wetlands, two-stage channel, large woody debris and refuge areas;

river bank vegetation management improved to increase diversity of emergent species;

creation of offline wetlands to increase aquatic habitat diversity;

landscaping planting to ensure that east bank of the diverted river remains inaccessible
to people and provides cover for movement of wildlife;

installation of bat tiles, bricks and boxes and bird boxes;

creation of artificial hibernacula and log piles for amphibians and invertebrate species.
8.8.9
A habitat creation plan detailing the environmental measures to be incorporated within the
scheme design will be written by a suitably qualified ecologist. This will provide a detailed
specification of the habitats to be created, together with a programme of works.
Furthermore, light, noise and pollution abatement strategies will be included within the
proposed scheme design and the construction environmental management plan.
8.8.10
As a result of the environmental measures to be included within the proposed development
design, it is concluded that there will be no long-term significant adverse effects on any the
ecological receptors that the site supports, although there will be some unavoidable
significant short-term adverse effects during construction. Indeed, the creation of additional
areas of broad-leaved planting, a new section of channel with associated offline wetlands,
the species-rich marshy grassland, log piles and the provision of additional artificial habitat
for otter, bats, birds and invertebrates, will result in ‘gains’ to ecological resources present on
site.
References
Document1

English Nature, 2001,”Great crested newt mitigation guidelines”, Peterborough

English Nature, 2004, “Bat mitigation guidelines”, Peterborough.

JNCC, 2010, “Handbook for Phase 1 habitat survey – a technique for environmental
audit“.
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9
Ground Conditions
Introduction
9.1.1
This chapter prepared by Applied Geology Ltd covers the existing ground conditions and
geology of the site and includes contamination and ground stability hazards associated with
construction and operational phases of the proposed development.
9.1.2
The chapter assesses the potential for the proposed development to result in effects on
geology, ground conditions, controlled waters (surface and groundwater quality), human
health (end users of the development and construction workers) and the built environment
(buildings and services).
9.1.3
The main issues relating to surface and groundwater quality are addressed in Chapter 7
Hydrology and Drainage. This Chapter covers potential impact to controlled waters by
ground conditions such as contamination of the ground.
9.1.4
The potential environmental impacts related to the issues covered in this chapter overlap
with other chapters of the ES, particularly Chapter 7 (Hydrology and Drainage). This chapter
should be read in conjunction with the other relevant chapters and also with reference to the
Water Framework Directive (WFD) Assessment (Appendix A.2), which has the aim of
establishing and maintaining good ecological and chemical status in all surface waters and
groundwater.
9.1.5
The structure of the chapter is such that initially a summary of relevant legislation and policy
is provided, together with a description of other documents and resources that have been
referenced. Details of the methodologies used to assess the potential significant effects of
the proposed development are then detailed and the existing characteristics of the ground,
contamination, groundwater and surface water on and in close proximity to the site are
described. The effects of the proposed development are then presented and where possible
measures to mitigate effects are described. This is followed by discussion of any remaining
residual effects and potential cumulative effects. The chapter is concluded with a brief
summary and reference list.
Policy Context
9.2.1
The assessment was conducted with reference to relevant policy and legislation.
National Policy and Legislation
9.2.2
Document1
Protection of Controlled Waters, namely rivers, estuaries, coastal waters, lakes and
groundwaters, in England is enacted through both National and European legislation.
Surface waters are primarily protected against the discharge of poisonous, noxious or
polluting substances by the Water Resources Act 1991 (amended 2003). This legislation
sets out the responsibilities of the Environment Agency (EA) in relation to water pollution and
the regulation of discharges to controlled waters.
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9.2.3
The European Commission’s WFD established a legal framework to promote the sustainable
use of Europe’s waters and restore clean water. There is an aim to achieve ‘good status’ for
all of Europe’s surface waters by 2015.
9.2.4
The Directive on Environmental Quality Standards (Directive 2008/105/EC) is a daughter
directive of the WFD and focuses on limiting the input of hazardous substances to the water
environment.
9.2.5
There are various CIRIA Reports and EA Pollution Prevention Guidance (PPG) that are
relevant to ground contamination and where this may impact on the aquatic environment.
However, these documents chiefly relate to the mainstream issues of water/groundwater
quality and hence are fully referenced in Chapter 7 (Table 7.1).
9.2.6
Legislation and guidance on the assessment of contaminated sites is provided under Part IIA
of the Environmental Protection Act 1990, as introduced by Section 57 of the Environment
Act 1995. This came into effect in England on 1st April 2000 as The Contaminated Land
(England) Regulations 2000. These Regulations were subsequently revoked with the
provision of the Contaminated Land England Regulations 2006 (Statutory Instrument (SI
2006/1380))3, which consolidated the previous regulations and amendments. These
Regulations, as well as, the Radioactive Contaminated Land (Modification of Enactments)
(England) Regulations 2006 (SI 2008/520) 4 came into force on 4th August 2006 – subject to
minor update in April 2012.
9.2.7
The National Planning Policy Framework (NPPF) 2012 provides advice on the implications of
contamination for the planning system and advises Local Authorities about the determination
of planning applications when a site is, or may be, contaminated.
9.2.8
Local planning policy controls are set out in the Planning Statement for the development.
These include:
9.2.9
Document1

Dacorum Local Plan 2004;

Draft Dacorum Core Strategy, June 2012 and modifications 2013;

Gade Zone Policy Planning Statement (GZPPS), 2012;

Hemel Hempstead Town Centre Masterplan, 2013.
Local planning policy related to ground conditions and contamination issues is limited to the
following:

Policy 11 of the Dacorum Local Plan sets out the requirement that development must
avoid harm arising from pollution in all its forms;

Policy C331 of the Draft Dacorum Core Strategy addressing water management requires
that development avoids damage to groundwater protection zones. The GZPPS also
outlines constraints to development relating to the Groundwater Protection Zone.
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Methodology
Baseline Data Collection
9.3.1
Site Investigation for the development has been undertaken by Applied Geology Ltd. This
comprised a review of previous investigations on the site by RSK, together with
supplementary combined Geotechnical and Geoenvironmental Ground Investigation.
9.3.2
The previous RSK investigations were reported in documents as follows:

West Herts College, Dacorum project, Factual Report on Ground Investigation, RSK
Group Plc, Ref 241370-01(00), August 2010;

West Herts College, Dacorum project, Report on Exploratory Contamination
Investigation, RSK Group Plc, Ref 241370-02(00), August 2010.
9.3.3
The full details of investigation works undertaken by Applied Geology, the data obtained and
assessments and conclusions reached, including the relevant information and assessment
from the previous reports, are published in the Report on Ground Investigation at West Herts
College and Morrisons Store, Marlowes, Hemel Hempstead, Applied Geology Report No.
AG1701-12-P84 Validated Issue 2 dated April 2013, included as Appendix D.2.
9.3.4
The main objectives of the investigation work were to:

Assess the potential for hazardous substances or conditions to exist in a situation likely
to warrant mitigation appropriate to the intended redevelopment;

Establish geological conditions and geotechnical parameters to permit safe and
economic design; and

Install groundwater monitoring wells to specifications and locations agreed with Affinity
Water to facilitate monitoring of groundwater levels before, during and after construction
works.
9.3.5
A site walkover survey and review of available desk study information held within the public
domain, together with a review of previous investigation undertaken at the site was initially
undertaken. The previous investigation, as referenced in 9.3.2, had comprised a total of 21
boreholes (formed using cable percussion and driven continuous sampling techniques), and
11 shallow hand dug trial pits at locations across the site. The supplementary further
intrusive investigations undertaken by Applied Geology (9.3.3 refers) comprised 12 driven
continuous sampling boreholes and 5 deep cable percussion boreholes. Three of the latter
boreholes were undertaken to facilitate the installation of groundwater data monitoring wells
to specifications agreed with Affinity Water.
9.3.6
Geotechnical and chemical laboratory testing was undertaken on selected samples obtained
during the investigation in order to determine the physical and chemical properties of the
soils underlying the site. Groundwater level monitoring within instruments installed within the
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boreholes has been undertaken during the period between November 2012 and present.
This monitoring is on-going at the time of writing.
9.3.7
Geotechnical and Geoenvironmental assessments were undertaken on the data to achieve
the objectives of the investigation. The investigation and assessments have been conducted
with reference to the following documents:

BS5930:1999 (A2)2010 “Code of practice for site investigation”;

AGS “Guidelines for Good Practice in Site Investigations (1998);

BS10175:2010 "Code of practice for the identification of potentially contaminated
sites";

CIRIA Report C665 (2007) “Assessing Risks Posed by Hazardous Ground Gases to
Buildings”;

BS1377: 1990 “Methods of Test for Soils for Civil Engineering Purposes”;

NHBC Standards, Chapter 4.2 (revised April 2011);

BRE Special Digest 1 (SD1) “Concrete in aggressive ground. Part 1: Assessing the
aggressive chemical environment” (2005);

Department of the Environment, Transport and the Regions & BRE “Radon: Guidance
on protective measures for new dwellings” (1999);

DEFRA & EA CLR11 “Model Procedures for the Management of Contaminated Land”;

EA “The UK Approach for Evaluating Human Health Risks from Petroleum
Hydrocarbons in Soil” (2005);

EA “Remedial Targets Methodology. Hydrogeological Risk Assessment for Land
Contamination” (2006);

“The Water Supply (Water Quality) Regulations” (1989) – updated by WFD;

HSE HSG66 “Successful Health and Safety Management”(1991);

CIRIA R132 “A guide for safe working on contaminated sites” (1996);

CIRIA C574 “Engineering in Chalk” (2002).
Potential Sensitive Receptors
9.3.8
Potential receptors to the development of the site associated with ground conditions, stability
and contamination have been identified. The identification of receptors has been informed
by an assessment of the baseline conditions and the assessment methodology has followed
the general methodology outlined in Chapter 5 of this ES.
9.3.9
The following potential sensitive receptors have been identified:
Document1

Human Health – including current and future occupiers, construction and future
maintenance workers and neighbouring properties/third parties;

Controlled Waters – ground and surface waters;
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9.3.10

Buildings and Property - on site current and proposed structures, neighbouring
properties, underground supply services (cables, pipes, ducts etc); and

Ecological Systems.
The value of each of the above identified receptors is assessed in relation to the site. The
proposed mitigation measures used to manage any significant effects (including
management of risk or elimination of pollutant linkage) have been identified. Residual effects
are then identified and further assessment of significance carried out.
Assessment of Significance
9.3.11
A judgement, based on relevant guidance and professional experience, has been made on
the importance and/or sensitivity of the receptors involved, as indicated in Table 9.1.
Table 9.1 Method for determining sensitivity/importance of the receptors
Receptor sensitivity
Description
High
Areas of critical topography, including steep slopes
Inner and outer groundwater source protection zones (SPZ 1 and
SPZ 2)
Areas of high groundwater vulnerability
Principal aquifers
Areas of known/confirmed contaminated land/groundwater
Surface water courses with good chemical status/high to good
ecological status*
End users of the site +
Neighbouring properties and residents +
Medium
Groundwater source protection zones - total catchment areas (SPZ
3)
Secondary aquifers
Areas with intermediate groundwater vulnerability
Surface water courses with good chemical status/moderate
ecological status*
Low
Industrial site topography
Surface water courses with poor chemical status/poor ecological
status*
Unproductive strata
Areas with low groundwater vulnerability
Construction workers +
* Surface water quality definitions are given in Chapter 7 (section 4)
+
Human health receptors are generally considered to be of high sensitivity. However, construction
workers are exposed to potential risks for relatively short duration and risks are sensibly mitigated by
standard Health and Safety procedures, hence are considered to be of low sensitivity.
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Magnitude of Change
9.3.12
Table 9.2 gives generic criteria for determining levels of magnitude of effect on the physical
environment.
Table 9.2 Magnitude of Effect
Magnitude
Definition
Major
Total loss or substantial alteration to key elements or features of
the baseline (pre-development) conditions such that the postdevelopment character, composition or attributes will be
fundamentally changed.
Moderate
Loss or alteration to one or more key elements/features of the
baseline conditions such that post development character,
composition or attributes of the baseline will be materially changed.
Minor
A minor shift away from baseline conditions. Change arising from
the loss or alteration will be discernible but not material. The
underlying character, composition or attributes of the baseline
condition will be similar to the pre-development circumstances or
situation.
Negligible
Very little change from baseline conditions. Change barely
distinguishable, approximating to a ‘no change’ situation.
Assessment of Significance of Impacts
9.3.13
The categories used when classifying the overall significance of potential impacts by
considering the sensitivity of receptor and the magnitude of effect are shown in Table 9.3.
Table 9.3 Effect Significance Matrix
Magnitude
Sensitivity of Receptor
High
Medium
Low
Major
Major
Major
Moderate
Moderate
Major
Moderate
Minor
Minor
Moderate
Minor
Not significant
Negligible
Not significant
Not significant
Not significant
Baseline Conditions
Existing Site Usage
9.4.1
Document1
The majority of the site is occupied by the West Herts College comprising a variety of low
rise buildings set in landscaped grounds with interconnecting pedestrian pathways. There
are college car parks in the northwest corner and in the southeast accessed off Dacorum
Way which traverses the site in an east-west alignment. The southern part of the site is
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occupied by the four-storey Civic Centre, which has undercroft car parking. The site also
contains the Marlowes Methodist Church. The River Gade flows north to south through the
lower lying western part of the site. Sporadic mature trees and shrubs are present within the
grassed areas in between the college buildings and especially along the banks of the River.
Site History
9.4.2
The site history as surmised from review of available historic mapping is presented in Table
9.4 below.
Table 9.4 Site History Summary
Document1
Map Date
On The Site
In The Vicinity Of The Site
1878
Alma Road with residential properties,
gardens, school and ‘Drill Hall’ in
north of site. Open field in centre of
site. Bath St with residential
properties, public baths and water
works in south. Stream courses close
to present alignment and along
western boundary.
Generally residential properties with
occasional industrial sites. Notably a
gasworks with gasometer and smithy
immediately west beyond the stream course.
1898
Buildings in north off Alma Road
Gasworks including gasometer no longer
include a smithy. Central field now
shown. Smithy no longer marked
developed with buildings including a
Chapel. Watercress beds between
water courses in central western area.
1925
The Smithy within the northern half of
the site is no longer labelled.
No significant changes.
1932-1947
Further development, predominantly
residential, of the central part of the
site.
Further development to the east of the site
with terraced residential properties.
1969
The site has been completely
redeveloped with all of the previous
buildings and structures having been
demolished and Decorum College,
made up of a number of large
buildings, and the Town Hall having
been constructed. The River Gade
that flows through the site has been
partially culverted re-directed and
reduced in size/width.
Directly to the north and west of the site is a
new road layout including a roundabout
Areas to the east, west and south have also
seen large scale mainly residential redevelopment and infrastructure change.
1969-1978
No significant changes.
Further commercial/industrial development to
the east, west and south of the site.
1970
No significant changes.
No significant changes.
1978-1990
No significant changes.
Area to the north of the site has been
developed with a bowling green, playing field
and a car park.
1993
No significant changes.
No significant changes.
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9.4.3
In summary, prior to the earliest historical map (1878), the site was occupied by residential
properties with a number of small businesses including a Smithy, public baths and water
works. By 1969 all of the buildings on site were demolished and redeveloped with Dacorum
College and the Town Hall (Civic Centre) remaining in this configuration to the present day.
During this redevelopment the River Gade has been partially culverted, redirected and
reduced in size.
Published Geology
9.4.4
The published 1:50,000 scale British Geological Survey (BGS) map, Sheet ‘238’ drift edition,
indicates the site to be underlain by Alluvium overlying Middle Chalk strata comprising the
White Chalk Sub-group. Made Ground is also anticipated across much of the site associated
with the historical development and redevelopment of the site including former housing and
the currently existing college buildings.
9.4.5
Copies of BGS archived well records associated with water supply boreholes present on the
site confirm the anticipated geology of the site of localised Made Ground overlying Alluvium,
both granular and cohesive in nature, overlying White Chalk.
Ground Conditions Encountered at the Site
9.4.6
The following descriptions of the strata present under the site are based on the ground
investigations undertaken by Applied Geology and others (9.3.1 refers) as detailed in the
Ground Investigation Report in Appendix D.2. A schematic long section illustrating the
ground conditions, through the west of the site parallel to the River Gade, is presented in
Appendix D.1.
Made Ground and Topsoil
9.4.7
Topsoil was encountered only in the southwest of the site extending below surface grass to
0.5m below ground level (bgl) and comprising orange brown sandy gravelly silt. Made
Ground was present across the site from ground level to depths of between 0.30m and 3.5m
bgl. Thicknesses of >1.5m were mainly limited to the northwest of the site. The Made Ground
comprised grass over brown sandy gravelly clay, sandy silty clayey gravel and occasionally
soft dark brown/black sandy gravelly silt. Various extraneous materials were occasionally
present including brick, concrete, plastic, metal, tarmac, glass, coal and pottery.
Alluvial Deposits
9.4.8
Document1
Alluvium has been encountered across the site, beneath the Topsoil or Made Ground, with
the base proved at depths of between 1.6m and 8.5m bgl. As might be expected, the
Alluvium was generally thicker and extending to greater depth in the west of the site nearest
to the River Gade. The Alluvium can be divided into two types - an upper horizon comprised
grey brown gravelly sandy silty clay and a lower horizon of grey brown sandy gravel
sometimes with pockets of silty clay. The Alluvium is classified by the Environment Agency
as a Secondary (A) Aquifer.
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White Chalk
9.4.9
Chalk strata have been encountered across the site beneath the Alluvium. The Chalk was
penetrated to a maximum depth of 35m bgl, although the base was not proven by the
investigations. The materials were described as structureless and composed of angular
gravel sized clasts of creamy white chalk in a creamy white and brown silty matrix. The
Chalk is classified by the Environment Agency as a Principal Aquifer. With respect to
potential risks related to natural chalk dissolution or man-made chalk cavities, the site falls
into a ‘low anticipated subsidence risk’ category in line with guidance in CIRIA Report C574
(2002).
Controlled Waters
9.4.10
The Groundwater beneath the site is a highly sensitive Controlled Waters receptor owing to
its Source Protection Zone 1 (SPZ) status and the presence of the on-site abstraction wells
for potable water supply. Groundwater was encountered during drilling as seepages, more
substantial flows and standing water at very variable depths ranging between 2.6m and
13.5m bgl in both the Alluvium and the Chalk.
9.4.11
Monitoring of groundwater levels within standpipes installed into boreholes was
subsequently measured at levels of between 2.66m and 5.90m bgl. The variation in these
levels is mainly a result of the difference in ground elevations between the east and west of
the site, although a general fall in groundwater levels from north to south is indicated. Using
the ground elevations extrapolated from spot heights given on the existing topographic
survey drawing, groundwater elevations of around 82.5m AOD are inferred in the north of the
site and 80.9m AOD in the south. This reflects the anticipated groundwater flow in a
southerly direction.
9.4.12
The output from groundwater data loggers over the wetter winter months of November
(2012) to February (2013) show the groundwater level within the Chalk aquifer to generally
fall relative to ground level, with the boreholes proximity to the on-site groundwater pumping
station. The borehole closest to the pumping station (CPBH1) recorded water levels of
between 3.85m to 2.30m bgl, whereas borehole CPBH3, located furthest from the pumping
station recorded levels ranging between 2.42m and 1.07m bgl.
9.4.13
A cyclic variation in groundwater levels was observed in all three boreholes, whereby a
sharp fall followed by a more gradual rise to near original level occurred every 12 hours.
Affinity Water have confirmed that this cyclic event is linked to their pumping regime at the
site.
9.4.14
The overall range of groundwater elevation recorded during this period is approximately
81.95m to 83.61mAOD. The highest elevations relate to the Christmas period when the
abstraction pumps appear to have been shut down for around 2 weeks. These overall
elevations are around 0.50m to 2.0m below the approximate water level in the adjacent River
Gade and this would suggest that the groundwater has not been in hydraulic connectivity
with the River during this period of monitoring.
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9.4.15
The locations of the boreholes are shown on Drawing No. AG1701-12-07 which is included
in Appendix A of the Ground Investigation Report which forms Appendix D.2 of the ES. The
groundwater monitoring data is presented in Appendix D of the Ground Investigation Report.
Soil Contamination
9.4.16
The previous earlier investigations included extensive soil testing across the site. These
have been reported and re-assessed (in the Ground Investigation Report – Appendix D.2)
to current human health screening levels for commercial usage and all concentrations are
below the relevant screening values. Total Petroleum Hydrocarbon (TPH) was recorded,
above the assessment value which has the potential to impact on buried plastic water supply
services, in shallow soils (at 0.3m bgl) in a single borehole in the north of the site.
Additionally asbestos fibres were identified in shallow samples (0.3m bgl) at 2 locations in
the north and west of the site. The 2012 supplementary investigations by Applied Geology
also included testing at locations across the site. All concentrations were below the relevant
human health screening levels except for two concentrations of benzo[a]pyrene (BaP) in
DCS2 at 0.4m bgl and DCS4 at 1.3m bgl, both in the northwest of the site. Statistical
assessment of these exceedences in the context of the overall dataset for BaP
demonstrated that the concentrations should not pose an unacceptable risk to human health.
9.4.17
The minor occurrences of contaminants encountered are not considered to warrant any
further investigation as the minor associated risk can be dealt with via standard construction
practise/simple mitigation measures. Given the sensitivity of the site in relation to the River
Gade, however, it is considered necessary to improve the coverage of soil sampling and
testing along the alignment of the proposed river diversion. Further investigation in this
regard should be considered as discussed in 9.6.
Groundwater Contamination
9.4.18
Chemical concentrations on five samples of water obtained during the previous investigation
(reported and assessed in the Ground Investigation Report, Appendix D.2) from monitoring
wells and from the River Gade, both upstream and downstream of the site were all below the
UK Drinking Water Standards (DWS) except for slightly elevated levels of TPH in two
locations in the central/eastern part of the site. Concentrations of potential contaminants in
samples of groundwater taken during the 2012 supplementary investigation by Applied
Geology were all found to be below current UK DWS.
9.4.19
The assessments made in the Ground Investigation Report (Appendix D.2) indicate that the
groundwater below the site has not been impacted by any contamination sources and that
the site is currently unlikely to pose a significant risk to groundwater.
Ground Gas Contamination
9.4.20
Document1
Monitoring of gas concentrations within standpipes installed during the previous investigation
was undertaken on four occasions. The full results are presented in West Herts College,
Dacorum project, Factual Report on Ground Investigation, RSK Group Plc, Ref 24137001(00), August 2010 which is presented as Appendix D.3.
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9.4.21
Concentrations of methane were below the detection limit of the equipment in all cases.
Carbon dioxide concentrations were generally below 1%, although a maximum of 4.3% was
recorded on one occasion. These concentrations were associated with very low flow rates
and oxygen levels generally close to normal atmospheric concentrations or slightly depleted.
9.4.22
A further four phases of gas monitoring were undertaken in standpipes during the 2012
Applied Geology Ground Investigations (Appendix D.2). Again methane concentrations
were not detected and carbon dioxide concentrations, although still generally low varied
between <0.1% and 7.2%. A maximum flow rate of 0.4 l/hr was recorded and oxygen levels
ranged from atmospheric to 14.2%. Current guidance on Radon protective measures for
buildings (BRE 211:2007) indicates that the site does not lie in an area where precautions
are required. The assessment is detailed in the Ground Investigation Report (Appendix D.2)
and concludes that no further assessment or mitigation measures are required in respect of
ground gases.
Potential Effects
9.5.1
Table 9.5 lists the identified receptors and their importance/sensitivity as assessed to the
criteria presented in section 9.3.
Table 9.5 Summary of Receptor Importance/Sensitivity
Receptor
Receptor Importance/Sensitivity
Human Health – Current and future site users,
neighbouring users
Local/High
Human Health - Site/construction personnel,
future maintenance workers
Local/Low
Controlled Waters – Chalk principal aquifer,
potable water supply, inner groundwater source
protection zone SPZ1
District/High
Controlled Waters – Alluvium, secondary aquifer Local/Medium
Controlled Waters – River Gade, local water
courses, surface water system
District/High *
Buildings and Property – On site buildings,
neighbouring properties
Local/Low
Ecological System – River Gade system
Local/High
* Although River Gade currently has moderate status, it has a target of good for 2015, and is a
designated salmonid water and chalk stream. Hence the River Gade has been assessed to have a
high importance.
9.5.2
Document1
The potential effects that may arise as a result of the proposed development of the site
associated with ground conditions and contamination have been reviewed in light of the
baseline information. These are described in the subsequent paragraphs divided into those
effects relevant to the demolition, construction and operational phases.
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Demolition
Human Health Receptors
9.5.3
Demolition of the above ground structures has the potential to disturb hazardous
substances, primarily asbestos that might be present within the building fabric. This presents
a potential adverse permanent effect on human health, for site personnel and neighbours,
through dust inhalation which will need to be addressed through standard mitigation
measures. If hazardous substances such as asbestos are not carefully managed and cause
contamination of the ground, this presents further risks for construction and future
maintenance workers.
Controlled Water Receptors: ground and surface water
9.5.4
Mobile hazardous substances such as fuels or oils present in existing above or below ground
structures have the potential to be disturbed during demolition. No such features were
identified during the investigation works and hence these are not included in the baseline
conditions. However, should such features be encountered unexpectedly; disturbance could
result in release of mobile contaminants into the ground, groundwater or surface water. This
potential directly adverse effect of temporary and short duration will again need to be
addressed through standard mitigation procedures.
9.5.5
Demolition work close to the River Gade has the potential to cause pollution. This potentially
direct adverse effect on the water course should be prevented by proper and carefully
planned demolition procedures.
Construction Phase
9.5.6
The construction phase will include earthworks, diversion of the River Gade, piling and
construction of the proposed development. Specific remediation works are not considered
necessary based on the investigation findings, although further investigation to increase
chemical sampling coverage along the proposed alignment of the River Gade is proposed as
described in the mitigation measures (section 9.6).
Human Health Receptors
9.5.7
New sources of contamination resulting from construction such as fuel/oil spillages or
construction residues, if unmitigated, could have minor direct adverse effects on human
health receptors.
9.5.8
Exposure to potential existing contamination in Made Ground via soil, water, dust or gas
during construction could also affect human health receptors.
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Controlled Water and Ecological Receptors
9.5.9
Mobile contaminants, such as fuel/oil spills could also have a potential effect on the River
Gade and Aquifers underlying the site. This adverse effect would be temporary and of short
duration.
9.5.10
Creation of new pathways for contamination from groundworks associated with general
construction, river and sewer diversion and piling have the potential to create new pathways
for contamination. The disturbance of the ground during construction operations has the
potential to affect the quality of the groundwater abstracted on-site for potable supply. This is
essentially a temporary potential effect of short duration, although the creation of new
pathways for contaminant migration for example as a result of the river diversion is a
potential permanent effect.
9.5.11
The temporary cessation of pumping, (for groundwater abstraction) during construction will
lead to a rise in groundwater levels, which could have potential effects on groundwater
quality. Other than the potential for creation of new contaminant pathways, it is considered
that there are no other potential permanent effects on the groundwater from the diversion of
the river.
9.5.12
Surface water runoff, infiltration and groundwater migration have the potential to pick up any
mobile contaminants and cause an adverse temporary effect to controlled water receptors –
the River Gade and Aquifers underlying the site.
Buildings and Property
9.5.13
Temporary changes in the groundwater table during construction will be caused by the
shutdown of the abstraction well and pumping to facilitate groundworks for the River Gade
diversion. However the effects on adjacent buildings, structures etc. due to the potential for
subsidence are considered negligible owing to distance from site and amount of water level
variation anticipated.
Operational Phase
9.5.14
The operational site will include all activities associated with the supermarket petrol filling
station (PFS), college buildings and large areas of hardstanding and car parking.
Controlled Waters
9.5.15
The PFS has the potential to have an adverse effect on controlled water receptors – the
River Gade, Aquifers (and hence effects on potable water supply) underlying the site. This is
essentially an effect on hydrology and hydrogeology and not directly related to ground
contamination, hence is covered in Chapter 7.
9.5.16
The completed development will reduce infiltration and better manage drainage of the site as
described in the Drainage Strategy (Appendix B.5). This is considered likely to have a
permanent direct beneficial effect as reducing infiltration will permanently reduce the
potential risk of contamination of the underlying aquifers and also reduced soil
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erosion/suspended solids reaching the River Gade. Chapter 7.5 also refers to this potential
effect.
9.5.17
The general increase in hardstanding and road network and associated increase in vehicular
access will increase the risk of contamination of surface run off from vehicular contaminants.
This could have a permanent direct adverse effect on the River Gade and the underlying
aquifers, hence public water supply.
Buildings and Property Receptors
9.5.18
Buried concrete structures can be subject to chemical attack by sulphates and/or acidic
conditions in the ground or groundwater. This is a potential direct adverse effect which will
require mitigation through appropriate design.
Mitigation Measures
9.6.1
Following the assessment of the baseline data and potential effects on ground related issues
from the development. It is considered necessary to undertake some further investigations,
along the proposed new alignment of the River Gade. This will involve trial pit or small
diameter shallow boreholes at intervals to obtain soil samples for chemical analyses. In-situ
testing and observations on groundwater behaviour should also be undertaken. These
investigations will be secured through a planning condition. The data obtained will provide
further detail of the ground conditions in this area of sensitive proposed works.
9.6.2
The proposed mitigation measures generally for the development have been split into
demolition, construction and operational phases as discussed below.
Demolition
9.6.3
A Construction Environmental Management Plan (CEMP) will be prepared to document the
environmental management procedures during demolition. The following construction
mitigation measures will be incorporated into the CEMP as appropriate.
Human Health Receptors
9.6.4
Prior to any demolition works taking place, a detailed hazardous materials survey (including
Asbestos) will be undertaken by a competent and appropriately qualified/certified party. Risk
assessments and method statements will be put in place by the Principal Contractor, and
used in the preparation of the Construction (Design and Management) Regulations (CDMR):
2007 health and safety plan. This will ensure that risks to site personnel and neighbours from
asbestos and other hazardous substances during the demolition are fully controlled and
mitigated and that prevention measures are in place to avoid the possibility of contaminating
the site as a result of the demolition activities.
Controlled Water Receptors
9.6.5
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Risk assessments and an appropriate method statement will also be put in place by the
Principal Contractor, as part of a CEMP, to avoid any disturbance or pollution of the site
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during demolition by mobile contaminants that could ultimately affect the River Gade and
underlying groundwater. The risk assessments will be further informed by the further works
outlined in 9.6.1. This will chiefly involve careful adherence to standard working practises.
Much of the guidance associated with working near water courses and preventing pollution is
listed in the Hydrology and Drainage Chapter (7.6.2-7.6.3).
Construction
9.6.6
A Construction Environmental Management Plan (CEMP) will be prepared to document the
environmental management procedures during construction. The following construction
mitigation measures will be incorporated into the CEMP as appropriate.
Human Health Receptors
9.6.7
Mitigation measures, such as appropriate PPE, and good hygiene practices, to protect site
construction personnel and neighbours from human health risks associated with the
construction works via new or existing sources of contamination, will be designed and
implemented in accordance with the CDMR: 2007. The health and safety plan under CDMR
will include reference to the ground investigation report and appropriate assessments
therein.
Controlled Water Receptors
9.6.8
The principal risk to ground and surface water during construction will result from the
potential migration of contaminants during groundworks. Measures will be adopted to
mitigate the risk to ground and surface waters associated with contaminated surface water
run-off arising from the operation of construction vehicles and general construction activities,
such as maintaining dry excavations, and use of spillages control equipment etc if
necessary. Such measures will follow the pollution prevention guidelines issued by the
Environment Agency and CIRIA (2001). The method statement for the realignment of the
River Gade is set out in the WFD Assessment (Appendix A.2).
9.6.9
Surface water runoff from the site is likely to increase during the construction phase due to
the removal of topsoil and vegetation and the introduction of temporary, less permeable
surface. As a consequence measures will be required to control surface water runoff and
provide controlled infiltration. These measures will include the appropriate use of temporary
bunding and settlement ponds to allow for isolation and on-site treatment of any sediment
laden or contaminated water prior to discharge to the drainage system.
9.6.10
Detailed measures for the prevention and control of potentially polluting spillages will be set
out in the CEMP. Spill control prevention measures are to include all vehicle fuelling,
concrete wash out and handling of potentially polluting materials, which should take place in
a designated area that will be bunded and drained via an interceptor. Oil and fuel storage,
and management of chemicals and hazardous materials will be in accordance with current
legislation and EA guidance.
9.6.11
General working practices including details of relevant guidance with regard to surface run
off protection erosion and pollution controls is set out in Chapter 7 (Ref 7.6.3).
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9.6.12
Groundworks and foundation construction including piling for temporary and permanent
works will be subject to a detailed risk assessment to assess that disturbance to the ground
does not present unacceptable risks to water quality in the River Gade and underlying
aquifers. The risks associated with piling are extensively set on in EA Report NC/99/73,
“Piling and Penetrative Ground Improvement Methods on Land affected by Contamination;
Guidance on Pollution Prevention”. A statement detailing the proposals with respect to a
formal foundation works risk assessment are set out in the Piling Statement (Appendix D.4).
The foundation construction risk assessment and detailed method statements to be finally
adopted will be agreed with Local Building Control, the EA, Affinity Water and Thames
Water.
9.6.13
Compliance with the CEMP will be monitored by regular monitoring of groundwater and
surface water conditions. The monitoring of groundwater and surface water conditions is
required in order to determine any trends or changes in background/baseline conditions. It is
necessary to ascertain whether the presence of the proposed development and its operation
is affecting the groundwater flow regime or the quality of the local groundwater and surface
water.
9.6.14
The monitoring programme undertaken as part of this baseline assessment will be further
supplemented by additional regular visits undertaken up until construction commences and
throughout the construction phase in order to identify possible effects of construction on the
baseline conditions.
Ecology and Wildlife
9.6.15
The measures to mitigate the risk to controlled water will effectively mitigate the risk to
ecology and wildlife as a result to ground conditions/contamination.
Operational Phase
Human Health Receptors
9.6.16
The potential risk of ingestion and uptake of contaminants by future site users will be
sensibly removed from the site owing to the extensive coverage of hardstanding and
buildings. In new areas of soft landscaping, a layer of imported topsoil, certified clean and
suitable for use, will provide a sufficient barrier in these areas to sensibly mitigate any further
risks. A greater depth of suitable soil cover will be required in landscaped areas where trees
or deep rooting shrubs are proposed.
Controlled Water Receptors
9.6.17
The PFS will include an above ground fuel storage system and full details are set out in the
PFS Specification document (Appendix B.7). Mitigation measures with regard to the PFS
are covered in the Drainage and Hydrology Chapter 7(7.6.16 to 7.6.18 provides full details).
9.6.18
The potential, generally, for polluted site run off to affect the underlying aquifer will be
mitigated by the use of a sealed drainage system. This will essentially isolate surface run off
from the aquifer and direct this, via gulleys and appropriate separator systems, to the
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existing surface water outfalls to the box culvert below the site. Details of this system are
referred to in the Hydrology and Drainage Chapter (7.6.14-7.6.15), and in the Drainage
Strategy Appendix B.5.
9.6.19
A permanent deep borehole (CPBH3) has been sunk in the centre of the site (see Appendix
D.2 for details) to specifications provided by Affinity Water. This will facilitate the future long
term monitoring of water levels and groundwater sampling to assess quality during the
operational phase of the development.
9.6.20
It is considered that the above measures will also, and equally, provide mitigation against
potential effects to the River Gade during the operational life of the development. Additional
enhancement measures in respect of the River Gade and adjacent corridor are discussed in
the Hydrology and Drainage Chapter (7.6.21-7.6.26).
Buildings and Property Receptors
9.6.21
The appropriate concrete design and specification for water supply pipework within the new
buildings will be sufficient to mitigate the risks of chemical attack and permeation during the
lifetime of the completed development.
9.6.22
Appropriate geotechnical design, as outlined in section 9.0 of the Ground Investigation
Report (Appendix D.2), will ensure the long term stability of the permanent structures to
avoid future ground stability risks.
9.6.23
Appropriate construction of hard surfacing/pavements, based on the soil parameters for the
site and in full accordance with the Highways Agency ‘Specification for Highway Works’ and
Local Authority requirements will mitigate against excessive vibrations and noise during the
operational phase.
Residual Effects
9.7.1
Mitigation measures for the adverse risks identified for the demolition, construction and
operational phases of the development have been identified including design, risk
assessment, method of construction and monitoring. Post mitigation residual effects are
presented in the following paragraphs.
Demolition
9.7.2
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The demolition of the existing buildings has the potential for major adverse effects, although
the mitigation generally involves adherence to simple and standard good practises and
hence the residual effects are considered only of minor significance. Table 9.6 below
presents the assessment of significance.
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Table 9.6 Summary of Demolition Phase Residual Effects
Nature of Effect
Receptor
(Sensitivity)
Mitigation
Magnitude
(Post mitigation)
Significance
Disturbance of
hazardous
substances
Human Health –
Site
personnel/neighbo
urs (High)
Hazardous
Material Survey,
H & S/ CDMR
procedures
Negligible
Not Significant
Disturbance of
hazardous mobile
substances
Controlled Waters
– River Gade and
underlying aquifers
(High)
Hazardous
Material Survey,
CDMR, CEMP
procedures
Negligible
Not Significant
Construction
9.7.3
Following mitigation, residual construction effects are assessed as generally not significant
or minor and it is noted that the planned construction period is approximately one year which
will further mitigate the potential likelihood and magnitude of adverse effects occurring. The
assessed significance of potential construction effects is presented in Table 9.7 below.
Table 9.7 Summary of Construction Phase Residual Effects
Nature of Effect
Receptor
(Sensitivity)
Mitigation
Magnitude
Significance
Exposure to new
and existing
sources of
contamination
Human Health –
Site personnel and
neighbours (High)
CDMR
procedures,
adherence to
good working
practises
Negligible
Not Significant
Ground
disturbance,
mobilization of
contaminants,
creation of new
pathways
Controlled Waters
– Aquifers and
River Gade
(Medium to High)
CEMP, Piling and
Groundwork
protocol
Minor
Minor Adverse
Contaminated
surface water run
off
Controlled Waters CEMP, Site
Minor
Control Measures
– River Gade and
Aquifer (Medium to
High)
Minor Adverse
Temporary
changes in
groundwater level
Buildings and
Property (Low)
Not Significant
None
Minor
Operational Phase
9.7.4
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The operational phase of the development is assessed to have only minor adverse
significant residual effects, although minor beneficial effects are also envisaged as a result of
reducing pollution and contamination risks associated with the reduced infiltration and better
managed drainage of the completed development. Table 9.8 below presents the
assessment of significance.
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Table 9.8 Summary of Operational Phase Residual Effects
Nature of Effect
Receptor
(Sensitivity)
Mitigation
Magnitude
Significance
(Post mitigation)
Fuel/oil spillages
associated with
PFS
Controlled Waters
– Aquifer and
River Gade
(Medium to High)
Above ground
storage, sealed
drainage
systems, alarms
and other robust
prevention
measures
Negligible
Not Significant
Increased
hardstanding and
vehicular traffic –
increased risk of
contaminated
surface water run
off
Controlled Waters
- Aquifer and
River Gade
(Medium to High)
Sealed drainage
system and
detailed strategy
of prevention
Negligible
Not significant
Reduced
infiltration owing
to sealed/better
managed
drainage
Controlled Waters
- Aquifer and
River Gade
(Medium to High)
Increased
hardstanding,
sealed,
managed
drainage
Moderate
Minor beneficial
Potential Cumulative Residual Effects
9.7.5
Considering the assessment findings, no potential cumulative residual effects relating to
ground conditions have been identified as resulting from the proposed development or
associated activities.
Summary
9.8.1
This Chapter considers the potential for the proposed development to result in ground
related impacts on human health, the built environment and Controlled Waters (surface
water and groundwater). The main issues relating to the latter are addressed in Chapter 7
Hydrology and Drainage and this Chapter deals with ground conditions, such as
contamination and where this might impact on Controlled Waters.
9.8.2
The main source of baseline data for the assessment has been from Site Investigations
undertaken by Applied Geology Ltd. These included a review of previous investigation work
including desk study information and additional further intrusive investigations across the
site. Monitoring installation have provided information on groundwater levels and the facility
for on-going monitoring extending beyond the construction phase.
9.8.3
The ground conditions underlying the site have been confirmed to comprise a sequence of
topsoil or Made Ground overlying cohesive and granular Alluvial deposits overlying the White
Chalk. Groundwater is present in the Alluvium and in the White Chalk. The latter represents
a highly sensitive Controlled Water owing to its SPZ 1 status relating to two on-site
abstraction wells for potable water supply.
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9.8.4
The groundwater elevations measured on the site suggest that the groundwater has not
been in hydraulic connectivity with the River Gade surface water during the period of
monitoring.
9.8.5
Generally no significant soil contamination issues were identified by the ground
investigations, although minor occurrence of TPH and PAH compounds were found along
with identified asbestos fibres at two locations.
9.8.6
The testing and assessments on the groundwater beneath the site have suggested that this
has not been impacted by any contamination sources.
9.8.7
The measurement of gaseous ground contaminants has also not identified any issues that
would require measures to be implemented.
9.8.8
The key sensitive receptors in relation to ground related issues have been identified as
human health receptors (end users, construction personnel and neighbours); controlled
waters (River Gade and underlying principal aquifer beneath the site); buildings and property
(proposed structures, buried substructures, underground supply services and neighbouring
properties; and ecological systems (chiefly the River Gade Corridor)
9.8.9
Assessments have been made based on relevant guidance and professional experienced
with respect to receptor importance, impact magnitude and significance of potential impacts.
The potential impacts on receptors have been identified and assessed separately for the
demolition, construction and operational phases of the development. The key areas of the
assessment relate to potential impacts to the River Gade and principal aquifer Controlled
Waters resulting from ground disturbance during construction.
9.8.10
Mitigation measures against potential adverse risks for the demolition, construction and
operational phases of the proposed development have been identified, including further
investigation work, design, risk assessment and operational protocols.
9.8.11
Post mitigation, residual risks relating to all phases of the development are generally not
significant. Residual minor risks are assessed in relation to Controlled Waters during the
construction phase only, although these will be further reduced as specific construction
activities are of very limited duration. During operation, there will be a minor beneficial effect
as a result of the reduced infiltration and sealing off of the underlying aquifer achieved by the
permanent drainage measures.
References
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
Water Framework Directive (WFD) Assessment – Development of The Link, Hemel
Hempstead, AMEC, may 2013

Water Resources Act 1991 (amended 2003)

The Directive on Environmental Quality Standards (Directive 2008/105/EC)

Part IIA of the Environmental Protection Act 1990
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
Environment Act 1995

Contaminated Land England Regulations 2006 (Statutory Instrument (SI 2006/1380))3

Radioactive Contaminated Land (Modification of Enactments) (England) Regulations
2006 (SI 2008/520)

Dacorum Local Plan 2004;

Draft Dacorum Core Strategy, June 2012 and modifications 2013;

Gade Zone Policy Planning Statement (GZPPS), 2012;

Hemel Hempstead Town Centre Masterplan, 2013.

West Herts College, Dacorum project, Factual Report on Ground Investigation, RSK
Group Plc, Ref 241370-01(00), August 2010;

West Herts College, Dacorum project, Repport on Exploratory Contamination
Investigation, RSK Group Plc, Ref 241370-02(00), August 2010.

Report on Ground Investigation at West Herts College and Morrisons Store, Marlowes,
Hemel Hempstead, Applied Geology Report No. AG1701-12-P84 Validated Issue 2
dated April 2013

BS5930:1999 (A2)2010 “Code of practice for site investigation”;

AGS “Guidelines for Good Practice in Site Investigations (1998);

BS10175:2010 "Code of practice for the identification of potentially contaminated sites";

CIRIA Report C665 (2007) “Assessing Risks Posed by Hazardous Ground Gases to
Buildings”;

BS1377: 1990 “Methods of Test for Soils for Civil Engineering Purposes”;

NHBC Standards, Chapter 4.2 (revised April 2011);

BRE Special Digest 1 (SD1) “Concrete in aggressive ground. Part 1: Assessing the
aggressive chemical environment” (2005);

Department of the Environment, Transport and the Regions & BRE “Radon: Guidance
on protective measures for new dwellings” (1999);

DEFRA & EA CLR11 “Model Procedures for the Management of Contaminated Land”;

EA “The UK Approach for Evaluating Human Health Risks from Petroleum Hydrocarbons
in Soil” (2005);
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
EA “Remedial Targets Methodology. Hydrogeological Risk Assessment for Land
Contamination” (2006);

“The Water Supply (Water Quality) Regulations” (1989) – updated by WFD;

HSE HSG66 “Successful Health and Safety Management”(1991);

CIRIA R132 “A guide for safe working on contaminated sites” (1996);

CIRIA C574 “Engineering in Chalk” (2002).

1:50,000 scale British Geological Survey (BGS) map, Sheet ‘238’ drift edition

UK Drinking Water Standards (DWS)

Construction (Design and Management) Regulations (CDMR) 2007

EA Report NC/99/73, “Piling and Penetrative Ground Improvement Methods on Land
affected by Contamination; Guidance on Pollution Prevention”.

Highways Agency ‘Specification for Highway Works’
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10
Socio-Economics
Introduction
10.1.1
This chapter assesses the socio economic impacts of the proposed development in terms of
its impacts on key receptors which, in this context, are taken to be businesses and residents.
Given the uses proposed for the site and those that will relocate as a result of the site’s
redevelopment, impacts are assessed at site, Hemel Hempstead and Dacorum Borough
levels. This chapter has been prepared by Peter Brett Associates LLP.
10.1.2
The key areas addressed in the socio-economic impact assessment are:

Employment impacts (direct, indirect and induced) both during construction and the
operational phases of developments;

Effects of the new foodstore on the local labour market and relating to retail spend;

Effects of the replacement college buildings on learning, the economy, vocational
training as well as social and community impacts; and

Off-site effects of the relocation of DBC services and also the Methodists Church.
Policy Context
National Planning Policy Framework (NPPF)
10.2.1
The NPPF sets planning policy for England. It provides a clear presumption in favour of
sustainable development. Each of the three roles of sustainability (economic, social and
environmental) is seen as mutually interdependent with the others, with planning needing to
address all three.
10.2.2
The NPPF states the government’s commitment to sustainable economic development,
urging planning authorities to plan positively to meet the development needs of business and
support an economy “fit for the 21st century”. Identifying priority areas for regeneration is
identified as one role of local plans, in support of sustainable economic growth.
10.2.3
The NPPF also supports planning policy to promote competitive town centres and their
management for growth, to ensure the viability and vitality of town centres. A sequential test
that prioritises town centre locations for main town centre uses is relevant to the retail use in
particular. Dacorum Borough Council’s emerging Core Strategy and Hemel Hempstead
Town Centre Masterplan follow this policy line through, as already discussed in the Planning
and Policy Context Chapter 6 of this ES.
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Hertfordshire’s Economic Development Strategy 2009 – 2021
10.2.4
The economic vision set out in this strategy states “by 2021, Hertfordshire will have a
resilient and low carbon economy characterised by quality jobs, innovative and dynamic
business, supported by a well skilled workforce and an entrepreneurial culture, where
everyone has the opportunity to prosper and fulfil their ambitions.”
10.2.5
The Strategy sets out five economic objectives, with those particularly relevant to this
regeneration project being:
10.2.6

Creating a vibrant low carbon economy, with economic growth in the ‘people’ sectors as
indicated by East of England economic projections (health care, retailing) and also in
knowledge sectors;

Developing a well skilled workforce, including increasing employment opportunities for
disadvantaged communities; supporting wider career choices; skills for innovation and
entrepreneurship; and skills meeting the needs of businesses; and

Creating vibrant towns and vibrant communities, including support for innovative
schemes that lead to additional trade and turnover.
The Hertfordshire Works Partnership who are responsible in part for delivering the economic
strategy notes five key factors underpinning its successful delivery and applicable to this
regeneration project: leadership, partnership working, aligning agendas, resources and
grasping opportunities. All of these five factors are at work in this proposed development.
Hertfordshire Local Enterprise Partnership (LEP) Plan for Growth
10.2.7
Since the County Economic Development Partnership produced its economic development
strategy, the Government has gone on to introduce Local Enterprise Partnerships. The
Hertfordshire LEP was approved in 2010 with a mission to accelerate business led economic
growth in the County. As such it is seeking steady and sustained economic growth with
objectives including encouraging enterprise and business growth; and improving the skills
and employment prospects of residents.
Dacorum Borough Council Corporate Plan 2009-14
10.2.8
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The Council’s Corporate Plan sets out the organisational priorities, which are:

Community – Tackle deprivation; celebrate differences; develop participation, give
influence to the community; work with children and engage with young people.

Resources and Value for Money – Optimise resources; attain level 2 use of resources
(Audit Commission); prioritise; implement best practise.

Environment – Keep the Borough clean, safe and green; mainstream environmental
sustainability.
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10.2.9

Economic Development – promote a sustainable local economy; attract investment;
regenerate the Borough.

Affordable Housing – Promote the building of new homes; maintain good social housing;
prevent homelessness; develop the private rented sector; maintain a five year housing
supply.

Profile and Reputation – Raise the Borough’s profile and identity; promote Dacorum as a
place to be proud of; communicate consult and inform.
The Corporate Plan refers to the continued use of the internal Improving Dacorum
Programme to deliver efficiency savings and value for money for the community, within the
context of continually restricted funding for service delivery.
Dacorum Development Programme 2011 – 2015
10.2.10 The Dacorum Development Programme brings together delivery of existing programmes to
generate a comprehensive Borough wide regeneration programme with thematic and spatial
priority areas. These include ‘economic development’ as a theme and ‘Hemel Hempstead
town centre’ as a spatial priority area.
10.2.11 The three programmes are:

The Sustainable Communities Strategy;

The Local Development Framework; and

The Local Investment Plan.
10.2.12 Core challenges identified in the Programme include:

Providing balanced and sustainable growth, working close to where you live; and

Regenerating Hemel Hempstead town centre, including corporate priorities of
redeveloping the Public Service Quarter and providing a new foodstore. Delivery of new
buildings as part of West Herts College is identified as an action as the College meets
training needs of local employers.
Dacorum Economic Development Strategy 2012 - 2015
10.2.13 Approved in October 2012, the Economic Development Strategy is focused around three
areas for actions and eight delivery streams. The three areas for action are intelligence
gathering; partnership building; and building on success (including progress on plans for
regeneration of Hemel Hempstead town centre).
10.2.14 Delivery streams include:

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Key sites and development: Establishing clear plans to help regenerate key business
areas, one of which is Hemel Hempstead town centre. The Town Centre Masterplan
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has been prepared to implement this, specifically identifying the public service quarter
incorporating the new college, retail foodstore and Civic Centre;

Regeneration: Incorporating the Hemel Hempstead town centre masterplan where it sets
out the vision as “In 2031 Hemel Hempstead town centre will be an appealing, attractive
and sustainable destination with a thriving economic centre and a high quality
environment. The regeneration and evolution of the town centre will emphasise the
natural and cultural assets of the town and celebrate its new town history and rich
heritage. Hemel Hempstead town centre will evolve into a vibrant place where people
want to shop, work, live, learn and visit.”; and

Skills and employment: Including developing the current and future workforce by
increasing practical skills levels; working with existing and new employers to understand
their skills needs to support the development of their businesses; and supporting
Dacorum’s residents to improve their skills and job prospects.
Dacorum Pre-Submission Core Strategy and Supporting Evidence Base
10.2.15 Strengthening economic prosperity is one of three central themes to the Pre-Submission
Core Strategy (a material planning consideration when determining planning applications),
whilst Hemel Hempstead is identified as the main centre for development and change in the
Borough. This is recognised in its strategic objective (9) to “strengthen confidence in Hemel
Hempstead’s role as a thriving sub-regional business centre and shopping hub.”
10.2.16 The benefits of the town centre focus should all generate more sustainable town centre
patterns of shopping trips. Measures proposed to achieve this are:

Improving the existing level of food shopping;

Generating more linked trips; and

Attracting more shoppers into the town centre.

The Pre-Submission Core Strategy takes these measures forward in Policy CS16, which
proposes around 6,000 m2 of additional convenience floorspace in Hemel Hempstead
over the Plan period. This is to be directed at the town centre in line with sequential test
requirements. The Core Strategy also sees Hemel Hempstead as the logical location for
employment growth, supporting its sub regional role (Policy CS14, further reinforced in
CS33)11.
10.2.17 Initiatives that help the Borough’s residents adjust to change and develop their skills are also
supported under the theme of strengthening economic prosperity.
11 Policies in the Pre Submission Core Strategy are underpinned by research studies providing the evidence. The employment study evidence is discussed
further in paragraph 10.6.2.
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10.2.18 Development of policies in the Core Strategy has been supported by a range of research to
provide the evidence on which policies are based. Two studies relevant to the proposed
development are the employment land study (Roger Tym & Partners, 2011) and retail study
(GL Hearn, 2011), both of which are discussed in Section 10.6.
Hemel Hempstead Town Centre Masterplan January 2013
10.2.19 The Town Centre masterplan sets out the key regeneration aims and objectives for the town
centre. These are focused on strengthening and diversifying the town centre economy (part
of its aim) and ensuring that it reaches its economic potential (an objective).
10.2.20 The masterplan identifies the need for regeneration of the town centre as it is outdated and
failing to reach its economic potential. Regeneration is required to create an appealing,
attractive and sustainable location with a high quality environment. The masterplan identifies
that the level of convenience shopping in the town centre is limited at present with a need for
an additional retail convenience foodstore. The masterplan identifies seven town centre
character areas of which the Gade Zone, in which the proposed site lies, is one. The Gade
Zone is identified as having significant regeneration potential for civic, educational, retail,
residential and community uses and is identified as the focus for regeneration for the next 10
years.
Summary
10.2.21 The policy framework provides support for sustainable economic growth, giving a focus to
revitalising town centres as one theme for support, a theme which cascades through into
County and Borough economic development policies and planning for economic
development.
10.2.22 Regeneration is a core corporate priority for Dacorum Borough Council, with Hemel
Hempstead a specific spatial priority. Within that, the key elements of this development
proposal are also stated actions/aspirations in policy; the foodstore, redeveloped college and
the redeveloped public sector quarter.
10.2.23 Development of skills for employment is also important in the policy context and articulated
at the County and Borough level through economic strategies.
Methodology
10.3.1
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The socio economic assessment has worked through the following methodology:

Establishing the baseline economic conditions in the areas of impact (Hemel Hempstead
and Dacorum Borough) using published data and statistical sources such as those
published by the Office for National Statistics (ONS), Department of Communities and
Local Government (CLG) and Nomis;

Assessing the current employment and service provision of the existing uses on site;
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10.3.2

Assessing the proposed employment and service provision of uses of the redeveloped
site and those of existing uses who relocate elsewhere; and

Examining the potential impacts of the proposed/relocated uses and their employment
and services implications and assessing these against the economic baseline and
current provision on site and the impact on local services infrastructure.
The socio economic assessment looks at three geographical levels in terms of area of
impact:

Site: the socio economic impacts of the changes that will take place from redevelopment
of uses, with some users moving elsewhere (the Borough Council and the Methodist
Church) and other users coming onto the site (foodstore).

Hemel Hempstead: the site cannot be viewed in isolation to the larger Hemel Hempstead
area as the cumulative socio economic impacts arising from its redevelopment and
encompassing all changing uses are greater and positive and go beyond the site
boundaries.

Borough: at the Dacorum Borough level as the impacts of services provided by both
Dacorum Borough Council and West Herts College are Borough wide.
10.3.3
The development being assessed is part of a wider regeneration initiative in Hemel
Hempstead town centre. This affects the scope of the assessment in relation to the current
Civic Centre which is currently within the site boundary of the proposed development and is
the base for a set of service delivery by the Borough Council. However, following this
development, new Civic premises will be provided as part of the wider developments out of
scope of the ES. This chapter therefore considers the impact on employment and service
delivery of relocation of the Civic Centre as part of the ES.
10.3.4
There are no generally accepted standard criteria for assessing the significance of socio
economic impact. The assessment of effects make use of the categories of significance
applied across all the sections of this ES from severe, major, moderate through to minor and
not significant, as shown in Table 5.1 in Chapter 5. This is based on scale of change and
makes use of professional judgement and guidance as necessary. In terms of employment
impacts are assessed in relation to overall employment levels in Hemel Hempstead and the
Borough as appropriate.
10.3.5
The method incorporates additionality calculations for employment impacts. This takes into
account the likelihood that not all jobs are additional i.e. some would be generated without
the development taking place and some of the new jobs will not benefit local people. In
order to move from the gross number of jobs associated with a project to the net number of
additional jobs the assessment takes account of leakage, displacement and deadweight
effects, together with downstream effects through use of multipliers. These are:

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Leakage: the proportion of impacts that benefit people/the economy outside the area of
impact, in this case Hemel Hempstead/Dacorum Borough;
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10.3.6

Deadweight: the proportion of outputs/outcomes that would have happened anyway if
the redevelopment of the site had not gone ahead;

Displacement: the proportion of outputs/outcomes that are reduced elsewhere in the
area of impact as a result of the development e.g. if an increase in jobs in one location is
at the expense of a decrease in jobs elsewhere; and

Multipliers: the further impacts from the local spend of those gaining jobs, which in turn
supports jobs elsewhere; and from the supply chain spend of businesses in the
development through local purchasing.
It is important to be clear about the socio economic ‘infrastructure’ elements that are scoped
into this assessment. This includes:

The services that are/will be provided by existing and proposed users of the site and with
socio economic impacts for residents and businesses; and

The services provided by those users moving from the site. These will have socio
economic impacts for residents and businesses with implications for net loss or gain of
services as a result of relocation.
10.3.7
Not included is any socio economic impact assessment of offsite premises development as a
part of relocation of existing users from the site, for example construction jobs to build the
new Civic Centre, or the development of other civic uses to the south of the proposed site
(Magistrate’s Courts, Police Station).
10.3.8
Discussion of socio economic impacts are grouped under the following headings:
10.3.9
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
Employment;

Labour Market (skills and training);

Public sector services;

Voluntary sector services; and

Retail spend.
Impacts are discussed in relation to the existing uses on the site (West Herts College,
Dacorum Borough Council and Hemel Hempstead Methodist Church). They form the
baseline for the assessment in relation to additionality of employment impacts. Impacts are
also discussed in relation to proposed uses (the redeveloped West Herts College and new
foodstore. The assessment of impact is based on the net overall impact taking into account
gains and losses as a result of relocation/redevelopment of existing uses.
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Baseline Conditions
Socio Economic Profile
Population
10.4.1
Population data is drawn from the Census 201112. When the assessment was completed
data was available for local authority areas (including Dacorum) but not within the Borough,
so the mid-year estimates are used to estimate Hemel Hempstead's population.
10.4.2
The estimated population of Hemel Hempstead is 87,358, of which the largest cohort (26%)
is aged 45-64. 20% of the population is aged 0-15 and 15% is aged 65 or more.
10.4.3
The 87,358 population in 2010 in Hemel Hempstead makes up 60% of the 2011 Dacorum
population of 144,800 people. Figure 10.1 in Appendix E.1 sets out 2010 population by
age. Although the Mid-Year Population Estimates and the Census data available to date use
slightly different age bands, it is clear that the broad age distribution is very similar over the
two geographies.
10.4.4
Between 2001 and 2011 there was an increase of 7,001 people in Dacorum (5.1%). This
compares to an increase of 7.8% in Hertfordshire and 7.9% across England and Wales. The
Interim 2011-based Subnational Population Projections 13 suggest that the Borough's
population will grow to around 155,000 by 2021 (an increase of 7%).
Economic Activity
10.4.5
The Annual Population Survey14 provides data on economic activity rates. Dacorum, along
with the rest of Hertfordshire has a higher economic activity rate and employment rate than
the England and Wales average (see Table 10.1). As a result the proportion of economically
inactive people and unemployed people 16-64 is lower in Dacorum and the rest of
Hertfordshire.
Table 10.1: Economic Activity Rates (Source: ‘Annual Population Survey July 2011-June 2012’)
England and
Wales %
Hertfordshire
%
Dacorum %
Economic activity rate - aged 16-64
76.5
80.9
79.2
Employment rate - aged 16-64
70.2
75.4
73.8
% aged 16-64 who are employees
60.2
64.1
58.3
% aged 16-64 who are self employed
9.7
11.0
14.6
Unemployment rate - aged 16-64
8.2
6.7
6.8
% who are economically inactive - aged 16-64 23.5
19.1
20.8
% of economically inactive who want a job
24.1
24.9
28.0
% of economically inactive who do not want a
job
75.9
75.1
72.0
12
ONS, Census 2001 and 2011
ONS, 2012 Interim 2011-based Subnational Population Projections
14 ONS, 2012, Annual Population Survey July 2011- June 2012
13
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10.4.6
Dacorum, along with the rest of Hertfordshire, has a higher proportion of unemployed who
want a job compared to the England and Wales average.
Labour Market Qualifications
10.4.7
Census data indicates that Hemel Hempstead's adults generally have a better level of
qualifications than the England and Wales average, with fewer with no qualifications and
more with level 1 and level 2 qualifications (see Figure 10.2, Appendix E.1). However,
there are fewer than average with higher level qualifications which may constrain growth in
some of the higher value knowledge-based sectors.
10.4.8
Adults in the rest of the Borough and the rest of Hertfordshire tend to have more high-level
qualifications than the England and Wales average, and this makes the lack of higher level
qualifications stand out in Hemel Hempstead.
Deprivation
10.4.9
The Index of Multiple Deprivation 2010 is used to assess whether areas are deprived relative
to other locations, using a system of rankings where 1 is the most deprived and 32,482 (the
total number of lower super output areas) is the least deprived. In comparison to the rest of
Dacorum there is relative deprivation in Hemel Hempstead although compared to the rest of
England there is little deprivation in Hemel Hempstead:

Of the 56 Lower Super Output Areas making up Hemel Hempstead, in 2010, 15 (27%)
were in the 20% least deprived in England; and

None were in the 20% most deprived.
10.4.10 However, the index of multiple deprivation is made up of a different domains which combine
to form the overall index. It is noticeable in Hemel Hempstead that the ranking in the
education, skills and training domain is lower than the overall ranking, suggesting a
systematic weakness. In particular there are 14% of the 56 Lower Super Output Areas
making up the town within the 20% most education, skills and training deprived in England
and 34% in the 21% to 40% most deprived. Figure 10.3 in Appendix E.1 shows further
detail.
Economic Structure
10.4.11 Hemel Hempstead accounts for 67% of the Borough’s employment. There were 39,740
workplace jobs in Hemel Hempstead in 201115. The main sectors were wholesale, retail and
professional/scientific/technical (each accounting for 11-12% of the total). This is shown in
Figure 10.4, Appendix E.1.
10.4.12 Along with the rest of Hertfordshire, Hemel Hempstead’s economy has relatively few jobs in
manufacturing compared to the England and Wales average; along with a higher than
average proportion of jobs in wholesale. Along with the rest of the Borough and to a lesser
15
Nomis, 2012, BRES 2011
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extent the rest of Hertfordshire, Hemel Hempstead has a relatively high proportion of jobs in
information and communications (9% of Hemel Hempstead employment compared to 4% in
England and Wales). Hemel Hempstead has relatively few public sector jobs (public
administration and defence, education and health) compared to the England and Wales
average.
10.4.13 Annual Business Inquiry data provides a comparison of workplace employee jobs over time
from 2003 – 2008 (see Figure 10.5, Appendix E.1). This indicates that while total
employment steadily rose across England and Wales 2003-2008, there was a static trend in
Hertfordshire and a decline in Dacorum.
10.4.14 Data for Hemel Hempstead 2003-200816 shows a very similar trend to the rest of Dacorum,
which is understandable as the town accommodates most of the Borough’s employment.
10.4.15 Within the overall employment trend:

Manufacturing employment has fallen in Hemel Hempstead as it has across England
and Wales, however, the fall has been more pronounced in Hemel Hempstead and
across Dacorum;

Construction employment has grown more rapidly in Hemel Hempstead than the wider
averages;

There has been relatively little change in distribution, hotels and restaurants across the
different geographies;

There has been a fall in transport and communications employment in Hertfordshire and
especially in Hemel Hempstead and Dacorum; compared to a rise across England and
Wales;

There has been a fall in banking insurance and finance employment in Hemel
Hempstead compared to a rise in employment in this sector across Dacorum and
England and Wales; and

Employment in public administration, education and health has increased across the
different geographies.
Retail, Education and Public Administration sectors
10.4.16 The proposed development has implications for the retail, secondary/higher/other education
and public administration sectors.
10.4.17 Within Hemel Hempstead there are an estimated 4,442 jobs in retail, 1,271 non-primary
education jobs and 1,156 public administration jobs (see Table 10.2). Hemel Hempstead
and the rest of Dacorum have a slightly higher than average employment in the retail sector
than the England and Wales average, but lower than average proportions in the education
and public administration sectors.
16
Note that this data is pre-recession
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Table 10.2: Employment in Retail, Secondary/higher/other Education and Public Administration sectors (Source: BRES 2011)
England and
Wales
Retail
2,598,118
Hertfordshire
Hemel
Hempstead
Dacorum
10%
68,909
13% 6,285
11%
4,442
11%
Secondary/higher/other
1,324,131
Education
5%
22,083
4%
2,645
4%
1,271
3%
Public Administration
5%
13,767
3%
1,674
3%
1,156
3%
1,238,170
10.4.18 Within the overall retail sector, ‘Retail sale in non-specialised stores’ (which includes
supermarkets) accounts for 1,740 jobs, making up 39% of all retail jobs in Hemel
Hempstead. This proportion is lower than the Hertfordshire and England and Wales
averages (50% and 44% respectively).
Occupational Structure
10.4.19 Dacorum has a higher proportion of the workforce in professional occupations and
administrative and secretarial occupations compared to the England and Wales averages;
and lower proportions of skilled trades, sales/customer service and process/plant/machine
operatives. Table 10.3 gives further detail.
Table 10.3: Occupational Structure (Source: ‘Annual Population Survey July 2011-June 2012’)
% managers, directors and senior officials
% professional occupations
% associate prof & tech occupations
% administrative and secretarial occupations
% skilled trades occupations
% caring, leisure and other service occupations
% sales and customer service occupations
% process, plant and machine operatives
% elementary occupations
England and
Wales
Hertfordshire Dacorum
10.3
19.2
14.1
11.0
10.7
9.0
8.0
6.4
10.9
12.8
23.1
16.2
11.9
9.5
9.3
6.4
3.2
7.3
9.1
21.5
19.6
13.5
8.3
9.0
5.3
4.3
8.0
Unemployment - Claimants
10.4.20 The proportion of the population 16-64 claiming job seekers allowance in Dacorum was 2.3%
in September 2012, close to the Hertfordshire average and below the England and Wales
average of 3.8%. The effect of the recession is clearly shown in the data (see Figure 10.6,
Appendix E.1) with current rates significantly above the historically low rates from 1999 to
2008.
10.4.21 The claimant count figures indicate sectors where claimants are looking for jobs. Within
Hemel Hempstead there is information for 890 of those that are claiming Job Seekers
allowance. Of these people, 44% are seeking sales assistants and retail cashiers work, 16%
are seeking elementary goods storage occupations, 14% are seeking general administrative
occupations and 6% are seeking elementary personal services occupations.
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Commuting patterns
10.4.22 Commuting data is only available from the last Census in 2001. This indicates that Hemel
Hempstead residents are more likely to work locally (less than 5km from home) than the
district, county or England and Wales averages. Along with the rest of the district, there is a
greater than average minority of the population travelling 30-40km to work, which is probably
accounted for by travel to work in London or other employment centres. Overall Hemel
Hempstead is relatively self-contained. Further detail is set out in Table 10.4 below.
Table 10.4: Residents Commuting Patterns (Source Census 2001, ONS)
Hemel
Hempstead
Dacorum
Hertfordshire
England and
Wales
Works mainly at or from home
8.4%
9.7%
9.4%
9.2%
Less than 2km
25.0%
21.4%
18.8%
20.0%
2km to less than 5km
23.6%
16.9%
15.5%
20.0%
5km to less than 10km
8.7%
11.8%
14.3%
18.2%
10km to less than 20km
12.7%
14.3%
15.2%
15.2%
20km to less than 30km
6.0%
6.5%
10.0%
5.4%
30km to less than 40km
7.6%
7.5%
6.0%
2.4%
40km to less than 60km
1.6%
4.9%
3.9%
2.2%
60km and over
1.3%
1.4%
1.6%
2.7%
No fixed place of work
5.2%
5.3%
5.1%
4.4%
Working outside the UK
0.1%
0.2%
0.2%
0.3%
Baseline – Current Users/Uses on Site
10.4.23 This subsection identifies existing users on the site in order to establish their current
operation in terms of services provided and people employed.
West Herts College
10.4.24 West Herts College is a large general further education (GFE) college and is one of four
colleges in the county of Hertfordshire. It has three main campuses: one new campus in
Watford, the Dacorum campus in Hemel Hempstead and one in Kings Langley. It also
provides courses in a number of community venues.
10.4.25 The overall college offers courses in all subject areas with the exception of agriculture,
horticulture and animal care. The majority of learners are enrolled on courses related to
business, public health services and care, arts media and publishing, and in retail and
commercial enterprise. This includes courses in construction, hairdressing & beauty,
hospitality and catering, performing arts as well as literacy and numeracy. The college has
its own work-based learning contract and offers train-to-gain vocational training, entry to
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employment and informal adult learning provision as well as providing education and training
for pupils aged 14-16 from local schools.
10.4.26 The Dacorum Campus in Hemel Hempstead provides a range of further, higher and
adult/community education and training opportunities for residents and supports training for
local employer needs for businesses. Redevelopment of the Hemel Hempstead campus is
the final phase of West Herts College’s property strategy, in order to address problems of
buildings now unfit for purpose, having high maintenance costs, poor accessibility, structural
inflexibility and limited ability to incorporate modern technology because of building structural
issues. The new premises as part of the proposed development complement the new West
Herts College campus in Watford through providing two campuses with comparable cultures
and learning experiences whilst offering different courses.
10.4.27 The Hemel Hempstead campus currently provides courses in bricklaying, plastering,
carpentry/joinery, access to HE, learners with learning difficulties provision, adult &
community learning, part time early years training, information technology BTEC and lifelong
learning network courses. The majority of courses are to level 3.
10.4.28 In 201017, approximately 3,359 learners aged 16-18 attended full-time and 225 attended
part-time across the whole College. A further 643 adult learners attended full-time and some
2,284 were on part-time courses. In addition, 41 learners were on Entry to Employment
programmes, 51 learners were on Train-to-Gain courses and 170 learners were on workbased learning programmes. A total of 666 pupils aged 14-16 attend college courses from
local schools. In summary this amounted to 500 full time and 1300 part time learners; 1800
learners in all.
10.4.29 The Dacorum Campus accounted for about a quarter of all the West Herts students, and the
most significant sector relating to the accommodation needs of the College during the day
time is full-time 16-18 year olds.
10.4.30 The college provides training on behalf of the following organisations:

John Laing Training (Construction);

Watford Football Club (Football coaching);

Skillnet (Motor Vehicle);

YMCA (Prince’s Trust); and

Best Practice (Train-to-Gain in customer service).
10.4.31 The 2010 OFSTED inspection report concluded that:

17
West Herts is an outstanding college that provides high quality education and training;
West Herts College Inspection report, 2010, OFSTED
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
Success rates are high on most courses and continue to improve, although on short
courses and on work-based learning programmes success rates remain below average
despite recent improvements; and

Success rates on Train to Gain courses are high and many learners on Entry to
Employment programmes progress to a positive destination. Framework completion
rates on work-based learning programmes are satisfactory overall.
10.4.32 There are 95 staff at the Dacorum Campus (including administrative and maintenance staff
as well as teaching staff). This is around 7.5% of employment in the secondary/higher/other
education sector in Hemel Hempstead. Taking account of part time working, this can be
expressed as a gross figure of 60 full time equivalent jobs (FTEs).
10.4.33 Applying additionality considerations to the gross FTE figure indicates a net FTE impact of
61.6 FTE. This assumes a low level of leakage as Hemel Hempstead has a relatively high
proportion of people living and working locally; and a nominal level of displacement given
that this is the only FE college in the Borough.
10.4.34 The presence of staff and students in the town centre has an impact on the town centre
businesses including food and beverage providers and a variety of comparison retail
businesses. There is no specific data available on the volume and location of spend
although it is noted that the average annual spend of a student attending a further education
college in England is £13,531 of which £8,407 is on living costs (which includes food,
personal items, entertainment, household goods, non-course travel and other living costs).18
For West Herts College students at least some of this expenditure will clearly be in the town
centre.
10.4.35 The college has a policy of local procurement and this benefits businesses in the local
economy although the policy also has to sit alongside the need to achieve best value for
money. As a result some contracts will be won by businesses from other locations.
West Herts College Opportunities and Constraints
10.4.36 In its Education Statement19 (Appendix E.2) that accompanied an earlier planning
application on the site and subsequent discussion, West Herts College has identified a set of
educational needs and opportunities, along with the constraints imposed on responses to
these opportunities. The needs and opportunities include:
18
19

Research undertaken by the College suggested that retail and construction skills would
be needed by the local economy;

Other research referred to by the College suggested additional level 3 and management
skills training, along with provision in health and social care, hospitality, logistics and
enterprise and sales skills. Employers have reported to the College that applicants for
hard to fill vacancies lack required qualifications, skills or experience, with management
Department for Innovation, Universities and Skills, 2009, Student Income and Expenditure Survey 2007/08
Education Statement, 2010, West Herts College
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positions often filled from outside the area. Poor customer service skills were cited as a
problem and employers advocated flexible training and an overall increase in the number
of young people entering higher education;

Other skills-demand research referred to by the College identifies 10 key employment
sectors for Hertfordshire, eight of which (business/finance; construction; retail; logistics;
social care; health care; education; and travel/tourism) are included within the planned
provision on the new Dacorum Campus;

There is the opportunity to reduce the number of young people not in education,
employment or training (NEETs). Historically there have been higher levels of NEETS in
Dacorum than the county average. The college has identified a set of partnership
working to address this. Linked to this a considerable number of Dacorum students did
not reach level 2 qualifications at the end of Key stage 4; and

The College has noted that within its catchment there are two wards in the bottom 10%
for education and skills deprivation, and the three wards in the bottom 20% (using earlier
IMD data and a different geography than the baseline above).
10.4.37 As identified by West Herts College the current Dacorum premises are well beyond their
working life and not suitable for modern educational requirements. The structural inflexibility
(because of asbestos) restricts the ability to create new learning spaces; it is uneconomic to
install modern technology and communications; and many rooms have poor acoustics. This
has resulted in sub-optimal room utilisation which has restricted effective capacity. Issues
around poor utilisation and the high cost of repairs have diverted funds away from education
resources, and this has been compounded by the high costs associated with cleaning
outdated buildings. Furthermore the building has poor accessibility for people with mobility
issues, and has a lack of suitable student social space and community space. In the
Education Statement20 (Appendix E.2) the College reported spend of £3.5m in the ten years
to 2010 and the need to spend a further £7.48m to 2015 to keep the College operational.
These factors have constrained the College’s aspirations to respond to the needs and
opportunities identified above.
Dacorum Borough Council Offices
10.4.38 Public Sector Services. The Civic Centre in Hemel Hempstead is the main location for
Dacorum Borough Council services and where all departments have their main office base
and Council committee meetings are held. There are 500 staff based at the Civic Centre
offices although there are some staff (e.g. environmental health officers) who will spend over
half of their time outside the office21. The Civic Centre provides access to the totality of the
Council services, accessed in the first instance via the customer service unit.
10.4.39 As part of a separate process the Council is refining the way it uses its resources to deliver
services as part of the Dacorum Delivers programme. This programme provides efficiency
savings in order to improve value for money and as a response to the Council’s reduced
20
21
Education Statement, ibid
Dacorum Borough Council, 2012, personal contact
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income22. As part of this the way that Council office accommodation is used has been
changing as staff work from the best location rather than the Civic Centre.
10.4.40 The Civic Centre also accommodates eight HM Revenue and Customs (HMRC) staff, who
operate a local Enquiry Centre.
10.4.41 Redevelopment. The Council’s existing Civic Centre far exceeds current and predicted
space requirements and requires a level of investment to bring it up to modern standards
which would represent very poor value for money. The deficiencies with the current Civic
Centre buildings are:23

It is too large for requirements (given new ways of working perhaps twice as large as
needed). It is understood from the Council that occupancy of the building is estimated to
be c. 40%;

Its construction and layout is inflexible, restricting alternative uses (including the
attraction of partners or commercial lettings);

It is expensive to operate and hugely inefficient in energy and other resource usage;

It has a requirement of over £4 million of investment over the next ten years simply to
address the fabric of the building and its services;

It fails to meet all requirements for disabled access;

As currently configured the building is incapable of allowing new and more flexible ways
of working including issues around IT/data provision and power delivery limitation; and

It offers a very poor working environment.
10.4.42 The current Civic Centre is within the site. It is part of the ‘Civic Block’, at the northern end of
the Town Centre, comprising a grouping of a range of public services, each in their separate
buildings and not all on the site. The Civic Block includes West Herts College, Dacorum
Borough Council Civic Centre Offices, the Magistrates Court, the Hertfordshire Pathfinder
Health Trust, the Police Station and the Library. Built in the 1960s, at very low density, every
building is aging, inefficient and no longer suitable for modern requirements.
10.4.43 Dacorum Borough Council has noted that: “an independent appraisal of the options for the
buildings at the northern end of the town centre, on land owned by the Council and other
public sector organisations identified that the because the buildings are old and inefficient,
the current arrangement offers poor value for money.”24
22
Dacorum Borough Council Corporate Plan 2009-14 Summary
Dacorum Borough Council, November 2011, Cabinet Report Agenda item 14
24
Press release: Public service hub for Hemel Hempstead Forward (May 2012)
http://www.dacorum.gov.uk/default.aspx?page=7544
23
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Hemel Hempstead Methodist Church
10.4.44 Voluntary Sector Services. Hemel Hempstead Methodist Church has a church and church
hall on the site. It currently provides two church services on Sundays (with additional
services on the third Sunday of the month). The Church/Hall lists a programme of events
during the week25 including bible study and fellowship groups and rainbows/brownie/guide
groups. The hall is not in use all day every day. The calendar of activities at Hemel
Hempstead Methodist Church is linked with that of the Bourne Methodist Church at
Northridge Way, Hemel Hempstead.
10.4.45 Work for this ES was unable to specifically identify the number of users or direct employment
associated with the church activities. It is estimated that the latter will be limited (c1 FTE) as
activities listed are those that are likely to be run by volunteers.
Summary
10.4.46 The uses currently on the site deliver a range of educational, public sector and spiritual
services. The number of people using these services includes 1,800 learners at the college,
potentially all of Dacorum’s residents through their receipt of the Council services (although
only a proportion are in direct contact with the Council at the Civic Centre), and the
congregation and other visitors to the church.
10.4.47 The employment used to deliver these services includes 95 staff at the college, 508 staff
based at the Civic Centre and a member of staff at the church – an estimated total of around
600 jobs. This makes up 1.5% of all jobs in Hemel Hempstead and:

The 95 jobs at the college make up 7.5% of the non-primary education jobs in Hemel
Hempstead; and

The 508 jobs in the Civic Centre make up 44% of the public administration jobs in Hemel
Hempstead.
Assessment of Effects
10.5.1
Potential effects are considered in terms of employment and services impacts of proposed
uses/users on the site and in relation to existing users relocating from the site. They are also
considered in relation to the construction phase and the operational phase of the
developments on site.
10.5.2
In terms of employment effects, it is worth setting this within the context of the most recent
employment study for Dacorum (Roger Tym & Partners, 2011), part of the evidence base for
the Borough’s Core Strategy. This study predicts jobs growth of nearly 10,000 from 20062031. Over 7,000 of new jobs are indicated as office based jobs with a further c.5,800 in non
B class uses26 (i.e. not formal employment uses as defined by the Town and Country
Planning (Use Classes) Order 1987 (as amended)). Regeneration and redevelopment in the
25
26
Hemel Hempstead Methodists Church: Calendar (updated monthly) http://www.hhmc.org.uk/church-calender
These increases in jobs are balanced by a predicted loss of employment in industry and warehousing.
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town centre should contribute to this employment growth. In this context, the Borough
Council offices are an important provider of office based employment and its relocation and
redevelopment facilitated by this planning application ensures the continuity of this office
employment. The proposed retail superstore will provide a number of new jobs in a non B
class use, as will the redeveloped College.
Construction Employment
10.5.3
There will be employment impacts arising from the demolition of existing and construction of
new buildings and their associated infrastructure. Cost estimates of the overall development
have been calculated and are inclusive of demolition, build costs, externalities, highways,
utilities and renewables/BREEAM standards27. These are £35.17million. Adding in a further
12% for fees gives a total build cost of around £40million.
10.5.4
West Herts College has indicated that the construction contract for the redevelopment of
college buildings will be awarded through an OJEU process 28. However, it intends to build
an obligation for apprenticeships into the tender and this will provide beneficial impacts and
links with the vocational skills provided by the College for the two-year period of construction.
10.5.5
Using UK wide data for the construction sector, it is estimated that one construction job year
is supported for every £165,000 spent on construction projects 29. Applying this to the total
construction cost, it is estimated approximately 250 job years will be generated by the
development in its construction phase. This is a beneficial short term impact.
10.5.6
On average 10 construction job years create one FTE 30. An estimated 24 FTEs will therefore
be generated from the demolition and construction works in the longer term. Taking into
account additionality considerations, this gives a net additional FTE impact of 21. This is
considered a beneficial and minor impact in a sector which grew in Hemel Hempstead 2003 2008.
10.5.7
Overall it is assessed the construction employment benefits as of minor beneficial
significance.
Effects on Services during Construction
10.5.8
It is estimated that the construction phase will result in the temporary relocation of College
and Council services for two years. The effects of this relocation are considered below.
Council Services during the Construction Phase
10.5.9
The Dacorum Borough Council Cabinet Report April 2012 indicates that the space
requirement for Council decant can be met within 30,000ft2 net plus meeting space for
Council and Committees (given that it is a temporary measure only), although this will
27
But exclusive of any developer contributions
This a tendering process for public contracts over a certain value must be published in the Official Journal of
the European Union as part of a competitive tender process.
29 ONS (2011) National Standard Extract from the Annual Business Survey, average of data from 2008-10 data
obtained 31/10/12
30 http://stats.oecd.org/Index.aspx?DatasetCode=TENURE_AVE
28
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require progress to have been made on flexible and remote working and may still require
some extra space to be taken.
10.5.10 The Council is still in the process of deciding which specific locations will be used for
accommodation during the construction phase and thereafter; although the alternatives are
all town centre sites in close proximity to the current location. For temporary accommodation
the Cabinet Report April 2012 suggests that maximum use will be made of 41 The Marlowes
(22,000ft2 net) and the Magistrates Court (c.11,500ft2). Contingency provision of a further
10,000ft2 has also been factored in.
10.5.11 The current changes in working practices (including any changes resulting in the current
fiscal climate) are planned to be complete before the decant. Discussion with the Council
has indicated that there are no changes to the services provided as a result of the
construction phrase, with the Customer Service Unit remaining the first point of contact for
access to the Council and direct discussion with the officers concerned for subsequent
discussion if required. This will include contact in person, by telephone, post and via the
internet.
10.5.12 Although the current arrangements with HMRC staff based in the Civic Centre are intended
to be short term, the HMRC services are anticipated to relocate with the Council during the
construction phase.
10.5.13 The lack of employment changes and continuity of service provision suggest that there will
be impacts during the construction phase will not be significant.
College Services during the Construction Phase
10.5.14 West Herts College is still in the process of deciding exactly which locations will be used to
continue the education services during the construction phase. Discussions with the College
have indicated that use will be made of a variety of owned and rented buildings in Hemel
Hempstead. The College has specified that the principles of preserving the learner
experience and learner successes will guide the final decisions about which accommodation
is used. It has also stated that while the College will preserve its presence in Hemel
Hempstead during the construction phase it reserves the right to provide some services from
other locations in line with the overriding learner experience and learner successes
principles.
10.5.15 While the construction phase may be a temporary event for the college, it will represent the
entirety of some of the learners’ further education experiences and so the delivery and
location of education during this period will be very important to the cohort affected.
10.5.16 Taking into account the possibility that further education will be provided at locations other
than Hemel Hempstead – with impacts on individuals’ travel – and in temporary premises, it
is likely that there will be some inevitable negative impacts on the West Herts College
services provided to learners. Given that the College is guided by the principles of
preserving the learner experience and learner successes it is assessed the scale of the
negative impacts during the construction phase as being of minor adverse significance.
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Operational Effects – On Site
Retail Foodstore Development
10.5.17 The Dacorum Retail Capacity Study update for 2011 (GL Hearn, 2011) indicated a need for
additional convenience retail foodstore capacity to serve Hemel Hempstead into the future,
with the advice being to focus this provision into the town centre (in line with NPPF
sequential requirements). The retail foodstore proposal contributes to this additional
capacity.
10.5.18 Employment. The proposed retail foodstore is a new provision to Hemel Hempstead. Direct
job estimates have been provided by the foodstore operator. Assumptions are then applied
following standard Government guidance in order to assess the additionality of the jobs, as
well as indirect and induced jobs.
10.5.19 Direct employment estimates are 350 jobs, 265 part time and 85 full time. This amount of
jobs would increase the number of retail jobs in Hemel Hempstead by some 7.9% generally,
and by around 20% in the ‘retail sales in non-specialised stores’ which includes
supermarkets. This is a beneficial impact on retail jobs in the town centre, although of minor
significance in the context of total retail employment there.
10.5.20 Information from the foodstore operator indicates a ratio of around 3 part time jobs to 1 full
time equivalent. The gross employment impacts of the foodstore are estimated therefore to
be around 175 Full-Time Equivalent (FTE) jobs.
Taking into account additionality
considerations, it is estimated net additional jobs arising from the retail foodstore will be
113.3 FTE. In making this assessment it is assumed a low level of leakage (jobs taken by
employees outside the Borough – assumed at 10%) but a higher level of displacement (jobs
displaced from other local businesses including retailers – assumed at 40%), using the
Department of Business, Innovation and Skills(BIS) research and English Partnerships
guidance31.
10.5.21 Labour Market Impacts. The new foodstore is likely to have a management team of around
35 full time employees. The remainder of the jobs created will be skilled butchers, bakers
and fishmongers, fork lift truck driver, sales consultants, stockroom assistants, and
administration and delivery positions.
10.5.22 The baseline review above has indicated that there are 890 people claiming Job Seekers
allowance in Hemel Hempstead. Of these people, 44% are seeking sales assistants and
retail cashiers work and 16% are seeking elementary goods storage occupations. This
suggests that the range of positions likely to be available at the foodstore will fit well with the
claimant profile as there will be people available locally to fill the positions on offer when the
foodstore opens. The foodstore operator will work with JobCentre Plus and the Local
Authority through a Local Employment Agreement, to work with unemployed people.
10.5.23 Retail spend impacts. An assessment of retail spend impact as a result of the foodstore
development has been carried out (Peter Brett Associates, 2012). This indicates a likely
31
English Partnership (2004). Additionality Guide, Second Edition.
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turnover for the proposed foodstore of around £39.4m in 2015 rising to £39.9m by 2017 32. At
present total turnover for convenience stores in the catchment33 for the proposed foodstore
is around £197.14m, of which £44.86m is in Hemel Hempstead town centre. As noted in
Paragraph 10.5.17, a requirement for an additional convenience retail foodstore in Hemel
Hempstead town centre is already identified and the foodstore development will meet this
requirement.
10.5.24 The Retail Impact Assessment to be submitted with the planning application indicates that in
the short term trade diversion to the new foodstore within the foodstore’s catchment area is
likely to be around £35.55m34 in terms of convenience goods trade diversion, and £5.08m in
terms of comparison goods trade diversion. A total of £4.3m convenience goods turnover
will be diverted from stores within Hemel Hempstead town centre itself. Whilst this will have
some impact on existing stores, earlier retail capacity work (GL Hearn, 2011) and that
undertaken for this proposed development, indicate that the two existing foodstores closest
to the site (the Asda and Tesco stores) are significantly over trading which would minimise
the impact of trade diversion. Trade will be retained in Hemel Hempstead town centre,
which is to the benefit of the town centre.
10.5.25 The proposed development will open up greater opportunities for combined shopping trips to
Hemel Hempstead town centre by providing a significant convenience foodstore focus which
should overall increase footfall through the town centre, including enhancing linkages with
the services and retailers in the Old Town. The development should therefore bring wider
trading benefits to the town centre also mitigating negative impacts on turnover of town
centre foodstores. It will also cater for the increase in convenience goods retail capacity
expected to arise in the longer term, in line with planning policy requirements.
10.5.26 Overall the retail spend impact is assessed as moderate beneficial.
West Herts College: Dacorum Campus Redevelopment
10.5.27 The new West Herts College Dacorum campus is intended to provide a facility of
architectural merit that will inspire learners. The College’s new campus in Watford provides
an example of this approach. The new campus in Hemel Hempstead will replace the
existing facility as well as the existing facility in Kings Langley. The courses currently
provided in Hemel Hempstead and in Kings Langley will be located in this new Dacorum
campus, along with the staff and students. The key impacts will relate to number of
students, numbers of staff and the range and level of courses provided. The scheme also
allows space for future expansion of the college on the North West corner of the site. While
there are no specific current plans for college activities on this area, any future college
development is likely to provide further benefits.
32
This figure is a total of convenience and comparison goods turnover. The foodstore will largely sell convenience
goods. There will be some comparison goods sales estimated at around 12.9% of turnover.
33 Defined as Zones 1-4 in the Retail Capacity Study update (GL Hearn, 2011)
34 There is an outstanding planning permission for an Aldi foodstore. If this is implemented trade diversion will rise
slightly to a combined total of £35.56m to the new foodstore and Aldi, of which £6m would come from existing
stores in the town centre.
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10.5.28 Learning Impacts. The student numbers will rise from the current 1,800 to 3,300. This
increase of 1,500 will include 1,100 students relocated from Kings Langley as well as 400
new students.
10.5.29 In addition to the existing courses, new courses will include plumbing, engineering (motor
vehicle and electrical installation), access to learning and work, travel and tourism, event
management and creative media. In addition, the majority of courses will be to level 4 (as
they are in the Watford campus) rather than the current level 3.
10.5.30 The additional staff numbers will take place from the beginning of the operational phase
along with 1,100 new students. The balance of 400 new students is estimated to take place
within 2-4 years. Details of the current and projected student numbers are shown in Table
10.5.
Table 10.5: Current and Projected Student Numbers (Source West Herts College)
Student Numbers
Current
Projected
Part time
500
2,200
Full Time
1,300
1,100
TOTAL
1,800
3,300
10.5.31 Part of the service delivery improvements identified by the College relate to the focus on two
campuses with comparable cultures and learning experiences (Watford and Dacorum). As
well as addressing the constraints associated with the current Dacorum campus, the new
facility will also address the constraints with the existing Kings Langley campus (too small,
restricted informal learning space and constrained and unsuitable location). The town centre
location is considered an important part of the overall learning experience, providing a venue
for student socialisation. Part of the Dacorum Campus’ role is to provide further education
for those located to the north of the joint catchment, for whom Watford is too far away.
10.5.32 The new building will have smaller maintenance requirement. This will release £7.48m
currently required for building repairs, which can be invested in the delivery of learning
outputs.
10.5.33 The learning impacts are beneficial. In the context of the change in the number of students,
range of courses, quality of the learning environment and level of qualifications, the impacts
are moderate to major in significance.
10.5.34 Economic Impacts. Staff numbers will rise from 95 to 160, as shown in Table 10.6. The
increase relates to the staff relocated from Kings Langley. This includes administrative as
well as teaching staff.
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Table 10.6: Current and Projected Staff Numbers (Source West Herts College)
Staff Numbers
Current
Projected
Actual Jobs
95
160
Full Time Equivalents
60
110
10.5.35 The economic impacts are beneficial. Although they are relocated jobs they are from outside
the areas of benefit covered by this assessment and can be considered additional; with
effects of minor beneficial significance.
10.5.36 Vocational training/Labour market impacts. The increased student numbers, range of
courses (including new courses in knowledge based industries - creative media) and the
provision at level 4 instead of level 3 will all produce beneficial labour market impacts.
10.5.37 In addition, the changes in courses and student numbers facilitated by the new campus will
further the current priority of enabling access to work. This is through helping people move
from Job Seekers Allowance to employment through vocational training, enhanced literacy
and numeracy and increased self-confidence. As part of this West Herts College has targets
to increase the number of adults with Level 2 qualifications through supporting employers in
priority sectors identified for the East of England, which include construction, health and
social care and retailing, some of which will be delivered through this campus.
10.5.38 West Herts College plans to take up discussion with the foodstore operator in due course
about provision of training for staff at the foodstore as well as opportunities for customer care
work placements for student pursuing a variety of disciplines.
10.5.39 The vocational training and labour market impacts are beneficial. The range of courses and
the focus on employability are important although some of this has been taking place
anyway. Overall the impacts are assessed as of minor beneficial significance.
10.5.40 Other Economic Impacts. The location of an additional 1,500 students in Hemel Hempstead
town centre along with 65 additional members of staff will increase the vitality of the town
centre and economic opportunities for business. Earlier discussion has referred to wider
evidence about the amount of overall expenditure by further education students and while it
is not possible to directly quantify the expenditure impacts for Hemel Hempstead, it is clear
that here will be additional retail and catering expenditure as well as spend on transport
services etc. In order to fully realise the opportunities presented the private sector will need
to respond with new businesses and services for this market. Both the old town and the
town centre provide opportunities for new businesses and it is likely that the opportunities will
be taken forward in due course.
10.5.41 The college will continue its programme of local purchasing and this will continue to provide
economic benefits to local suppliers.
10.5.42 The economic impacts from the additional students and staff are beneficial and are likely to
be minor in significance in comparison to the overall use of the town centre.
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10.5.43 Social and Community Impacts. The new Dacorum campus will be operated as an
accessible 7-day per week facility for a variety of community and business uses. This will
mirror the approach taken in the new Watford Campus which is used by various groups (e.g.
church meetings, autistic society film shows etc.) as well as a training and meeting venue for
businesses. West Herts College will promote this opportunity although it is likely that these
uses will need to build up over time.
10.5.44 The social and community impacts from wider use of the new campus are beneficial and are
minor in significance.
Operational effects - Off Site
10.5.45 This part of the assessment considers the activities and services that are currently provided
on the site but will, following the redevelopment, be moved off-site.
Dacorum Borough Council Redevelopment
10.5.46 The Dacorum Borough Council Cabinet Report April 2012 indicates that the new council
offices proposals respond to the service delivery issues stemming from the old and inefficient
buildings and that inclusion of the new offices in a 'public service quarter' would bring:

Benefits to the community, being able to access a wide range of services from a single
point;

Regeneration of the existing civic block land, bringing investment into the area;

Economies of scale from sharing facilities and costs across organisations; and

New energy efficient building techniques and new ways of working to reduce running
costs.
10.5.47 In their Cabinet Report, November 2011 the Council is clear 35 that the primary motivation for
a new ‘public service quarter’ is on its regeneration potential and that it will not simply be a
‘new’ Civic Centre. The emphasis, therefore, is to deliver a community focused building with
as wide a range of public and voluntary sector presence as possible with a particular focus
on a new library. The Council believe that the following objectives are achievable 36 as part
of the public service quarter, these are:
35
36

designed for the next 50 years with a ‘citizen focus’ and capable of adaptation as
technology and consumer requirements change;

to deliver a modern library (information/learning/interaction), and space for the voluntary
sector and commercial possibilities;

To deliver new ways of working to reduce overall space requirements for staff and
volunteers and so reduce costs. For instance, making better use of available spaces
Dacorum Borough Council, November 2011, Cabinet Report Agenda item 14
Dacorum Borough Council, November 2011, Cabinet Report Agenda item 14
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through avoiding dedicated workstations, home/distance working, making use of modern
ICT and communications and shared/partnership working;

To act as a catalyst for either town centre regeneration in Hemel Hempstead or for a
stimulus to development within Maylands business park to the east of the town. This
allows a ‘win-win’ in that regeneration can be stimulated by use of the Civic Block and in
the delivery of a new and modern public service quarter;

To produce a value for money, exemplar, building in terms of design, sustainability and
flexibility; and

Getting good financial value from the Council’s (and other partners) land holding at the
Civic Block, freeing funds for service delivery.
10.5.48 The Council is still in the process of deciding which specific locations will be used for the new
council offices; although the alternatives (Pavilions site, Water Gardens Car Park) are all
town centre sites in close proximity to the current location.
10.5.49 Council and Community Services Impact. Discussion with the Council has indicated that
there will be no direct changes to the services provided as a result of operation from new
offices in the public sector quarter. The Customer Service Unit remains the first point of
contact for access to the Council. Direct discussion with the officers concerned will continue
for subsequent discussion if required. This will include contact in person, by telephone, post
and via the internet. HMRC services are anticipated to remain located with the Council.
10.5.50 Dacorum Borough Council has already started the process of technological, operational and
cultural changes as part of the ‘Dacorum Delivers’ programme and this (including any
changes resulting in the current fiscal climate) is due to be complete before relocation.
10.5.51 In addition to the council and HMRC services that will continue to be provided, there are
discussions about additional services, including in the voluntary sector, to be provided as
part of a joint public service quarter facility. New providers are planned to include:

Citizens Advice Bureau (relocated from Dacre Road);

Mediation Services (relocated from Halsey Drive on the outskirts of Hemel Hempstead);

Relate (relocated from St Mary’s Road); and

Registration Office (relocated from The Bury).
10.5.52 The plans for the new hub within the public service quarter include a public meeting suite
with 10 rooms.37 It is also planned that this joint facility will include a new library with
additional space as well as an open plan format with a café. The combined service provision
and the improved environment are expected to increase the number of visitors to the various
public sector service providers as well as improving the experience of service users.
37
Dacorum Borough Council, November 2011, Cabinet Report Agenda item 14
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Although these facilities will be in the redevelopment outside this ES, the development within
this ES directly facilitates these changes to services.
10.5.53 The continuity of Council service provision on a new site and the co-location of other
community services in an enhanced environment are assessed as having an impact of minor
beneficial significance.
10.5.54 Employment Impacts. The re-provision of Council premises is not with the site. Although
this represents a loss of the 500 jobs from the current site the key point is that these jobs will
be re-provided on an adjacent site within Hemel Hempstead town centre. There will be no
loss of employment and therefore no negative employment impacts from this redevelopment.
The co-location with the other community services is likely to have little or no net change as
these are already in place elsewhere in the town, there will be no significant impacts.
Hemel Hempstead Methodist Church Relocation
10.5.55 A planning application has been approved for rebuilding of the Methodist Church at
Northridge Way. The rebuilding of the Bourne Methodist Church (on the junction of
Northridge Way and Ashtree Way) received full planning permission in November 2011 and
is proposed as one building combining church and meeting rooms/hall.
10.5.56 The new church is likely to combine the activities from the Hemel Hempstead Methodist
Church on the site with those of the Bourne Methodist Church on Northridge Road (which is
the church to be rebuilt). Activities from the Methodist Church on the site are expected to be
relocated to the Bourne Methodist Church in Hemel Hempstead which is just over one mile
from the site, to the west. Therefore, the impacts are assessed as neutral and not significant
for the purposes of this assessment.
Regeneration Economic Impacts
10.5.57 The Dacorum business survey discussed as part of the baseline noted that along with
location costs and parking issues, the image of Dacorum was a negative factor affecting
running their businesses. Discussion with the Council has informed the assessment that this
redevelopment will have a positive impact on the image of Hemel Hempstead and the rest of
Dacorum. There is likely to be a cumulative positive affect when considered with the 2005
retail and residential Riverside development on the southern side of the town centre, with the
likelihood that the town will be able to present itself as a rejuvenated location with the
confidence to invest. This is likely to have positive impacts on perceptions of the town as a
location to live, visit and invest in. As already noted the foodstore should also contribute to
greater linked shopping trips to the town centre, supporting and improving its economic
position.
10.5.58 On balance it is assessed as a minor beneficial impact.
Mitigation
10.6.1
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assessment of effects in Section 10.4, inherent mitigation includes:
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
Delivery of construction jobs;

Direct new employment provided in the foodstore with the potential for training
opportunities to the benefit of the local labour market;

Creation of a new learning environment, with space for more students and a greater
range of courses and new quality teaching facilities;

Provisions in place to ensure the continuity of Council services; and

Retention of community facilities as part of a relocated Methodists Church.
10.6.2
The discussion within this socio-economic assessment has identified that the majority of
impacts are beneficial or there is no overall impact / impacts are not significant.
10.6.3
One negative impact is identified related to College Services during the ‘decant’. Section
10.5 above has indicated that the process of relocation, the use of temporary premises and
the possibility that some learning will be temporarily provided outside Hemel Hempstead.
This may have a minor adverse impact on the learners at the Dacorum Campus during that
time. Section 10.5 suggests that there may be benefits from College apprenticeships with
the construction companies and this as a way of mitigating impacts. Additional mitigation
could include recompense for additional travel costs if some students have to make longer
journeys during the ‘decant’ period. Therefore, this impact is temporary and following
mitigation will be reduced to and is not significant.
10.6.4
In the longer term the college impacts are all positive.
10.6.5
The scale of impacts for each proposed use on site and uses relocated elsewhere have
been summarised in Table 10.8 below.
Table 10.8: Residual impacts by facility
Type of Impact
Assessment of Impact
Construction Phase
Construction 21 net additional FTE jobs
Minor beneficial
Council services during ‘decant’
Not significant
College services during ‘decant’
Not significant
Operation Phase
Foodstore: 113 net additional FTE employment
Minor beneficial
Foodstore: labour market impacts
Minor beneficial
Foodstore: retail spend & town centre impacts
Moderate beneficial
College: 65 actual relocated employment impacts
Minor beneficial
College: learning impacts
Moderate to major beneficial
College: vocational training/labour market impacts Minor beneficial
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College: other economic impacts
Minor beneficial
College: social and community impacts
Minor beneficial
Council and community services: impact
Minor beneficial
Council and community services: employment
Not significant
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10.6.6
Type of Impact
Assessment of Impact
Methodist church relocation: employment impact
Not significant
Methodist church relocation: services impact
Not significant
Regeneration: economic impacts
Minor to moderate beneficial
Once more detail is known future beneficial impacts may accrue from new educational
development on the north west of the site covered by the outline planning application.
Summary
10.7.1
The planning and regeneration policy context supports the revitalising of town centres and
specifically the development of Hemel Hempstead town centre as a focus for business and
shopping. There is specific policy support for the development of further convenience retail
floorspace in Hemel Hempstead town centre. Proposals for the Gade Regeneration Zone, in
which the proposed development lies, support its potential redevelopment for civic,
education, retail, residential and community uses.
10.7.2
The socio economic impact assessment has assessed potential impacts of the proposed and
relocated uses against an economic baseline of data about Hemel Hempstead and Dacorum
Borough, in relation to the current uses on the site and their socio economic impacts and in
terms of their impacts on local services infrastructure. It has looked at impacts in terms of
employment, labour market (skills and training), public/voluntary sector services and retail
spend. The assessment of impact is based on the net overall impact taking into account
gains and losses as a result of relocation/redevelopment of existing uses.
10.7.3
Overall, the proposed redevelopment of West Herts College and the Civic Centre to provide
a new college and new foodstore provides a strong set of positive socio-economic impacts.
Some of these – particularly the learning impacts and the regeneration economic impacts –
are beneficial and of moderate significance. The one potentially negative impact relating to
the college decant is reduced to not significant through mitigation.
10.7.4
While some services will no longer be provided on this site, the redevelopment will allow an
improved set of these services to be delivered from an adjacent location within the town
centre, thereby nullifying any potential negative impact from loss of services or the
employment resources delivering them.
10.7.5
The assessment has indicated that many of the individual beneficial impacts are minor,
along with the regeneration minor to moderate beneficial impact and the learning moderate
to major beneficial impact. When considering the impacts as a whole rather than individually
the assessment changes and takes into account the following:
10.7.6
Taken as a whole the scheme socio-economic impacts are therefore assessed as moderate
beneficial.
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References
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
Dacorum Borough Council (2012). Economic Development Strategy 2012 – 2015.

Dacorum Borough Council (2013). Hemel Hempstead Town Centre Masterplan

Dacorum Borough Council (2012). Dacorum Development Programme 2011 – 2015

Dacorum Borough Council (2011). Proposed Modifications Core Strategy: Presubmission, January 2013

GL Hearn (2011). Retail Study Update. Dacorum Borough Council 2011.

Hertfordshire Works (2010). Hertfordshire’s Economic Development Strategy 2009 –
2021: A summary

Hertfordshire Local Enterprise Partnership (2012?). Open for Business

Peter Brett Associates (2012). Retail Impact Assessment. Document submitted with
planning application

Roger Tym & Partners (2011). Employment Land Update 2011. Dacorum Borough
Council, 2011
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11
Townscape and Visual
Introduction
11.1.1
This Townscape and Visual Impact Assessment (TVIA) has been prepared by DLA
Landscape and Urban Design. The site assessed in this TVIA is indicated on Figure 11.1
(Appendix F.1).
11.1.2
This chapter of the ES describes the existing Townscape and Visual sensitivities within and
surrounding the site and the magnitude of the proposed development on baseline conditions.
The townscape and visual resource are separate issues but are closely related as described
below.
11.1.3
The consultation draft of third edition Guidelines for Landscape and Visual Impact
Assessment (GVLIA) (LI & IEMA, 2012) describes townscape and its assessment as follows.
“Townscape refers to areas where buildings and related infrastructure are the dominant
components." Furthermore, "townscape means the landscape within the built up area,
including the relationships between buildings and different types or urban greenspace.
Townscape assessment is a form of landscape character assessment that focuses on these
predominantly developed landscapes.” (S.3.3)
11.1.4
Although the term 'townscape' refers to the physical fabric of a place, the arrangement of
buildings, infrastructure and vegetation create particular types of views, which contribute to
the perception of character.
11.1.5
Visual Impact Assessments refer to the quality and sensitivity of existing views available
from receptors and how these will change as a result of a proposal. As such, it is important
to make reference to the physical components of townscape present or proposed in key
views.
11.1.6
Townscape and visual resources are closely related to one another but are separate issues
and are required to be considered under independent assessments.
Policy Context
11.2.1
Following on from the policy and planning context in Chapter 6, this section outlines
planning policies and guidance relevant to the townscape and visual impact assessment.
National Planning Policy
National Planning Policy Framework (March 2012)
11.2.2
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The National Planning Policy Framework sets out the government’s planning policies for
England and how these are expected to be applied. It states, “the purpose of the planning
system is to contribute to the achievement of sustainable development." (p2) The NPPF
notes that pursuing sustainable development involves seeking positive improvements in the
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quality of the built, natural and historic environment, as well as in people’s quality of life,
including (but not limited to) replacing poor design with better design.
11.2.3
The NPPF contains 12 core principles, which states that planning should "Take account of
the different roles and character of different areas, promoting the vitality of our main urban
areas...”
11.2.4
Paragraph 56 emphasises the importance of high quality design, and inclusive design, “for
all development, including individual buildings, public and private spaces and wider area
development schemes." With regard to achieving high quality places, paragraph 58 explains
that decisions "should be based on ... an understanding and evaluation of its defining
characteristics" and should ensure that developments:

Establish a strong sense of place, using streetscapes and buildings to create attractive
and comfortable places to live, work and visit;

Optimise the potential of the site to accommodate development, create and sustain an
appropriate mix of uses (including incorporation of green and other public space as part
of developments) and support local facilities and transport networks;

Respond to local character and history, and reflect the identity of local surroundings and
materials, while not preventing or discouraging; and

Are visually attractive as a result of good architecture and appropriate landscaping.
11.2.5
Paragraph 61 goes on to state that planning policies and decisions "should address the
connections between people and places and the integration of new development into the
natural, built and historic environment."
11.2.6
In relation to design quality, paragraphs 63 and 64 state, "In determining applications, great
weight should be given to outstanding or innovative designs which help raise the standard of
design more generally in the area. Permission should be refused for development of poor
design that fails to take the opportunities available for improving the character and quality of
an area and the way it functions.”
11.2.7
Regarding the natural environment, "the planning system should contribute to and enhance
the natural and local environment by...protecting and enhancing valued landscapes..."
(paragraph 109)
11.2.8
Consideration to historical assets is outlined in paragraph 128 whereby, "the applicant is to
describe the significance of any heritage assets affected, including any contribution made by
their setting. The level of detail should be proportionate to the assets’ importance and no
more than is sufficient to understand the potential impact of the proposal on their
significance."
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Local Planning Policy
11.2.9
At the local level, the Dacorum Borough Local Plan (2004) remains current and provides
local planning policy for the Borough. However, the emerging Core Strategy, which has not
been finally submitted for approval will also be a material consideration. Key local
documents that are particularly relevant to the TVIA have been summarised from both
documents.
11.2.10 Policy 10 relates to optimising the use of urban land. It states:
“Proposals for new development will be judged against the following principles to secure the
optimum use of land in the long term:
(a) All development must be planned and implemented in a coordinated way, taking a
comprehensive view of potential development opportunities in the immediate area
wherever possible.
(b) General building development should be designed to achieve the maximum density
compatible with the character of the area, surrounding land uses and other
environmental policies in the plan.
(c) The design and layout of new development should not inhibit positive management of
land and buildings. Arrangements for future management should be put in place in
appropriate schemes.”
11.2.11 Policy 99 relates to the preservation of trees, hedgerows and woodlands. It states:
“Encouragement will be given to the preservation of trees, hedgerows and woodlands
(including old orchards) throughout the Borough,” and includes the council’s use of Tree
Preservation Orders to “ensure the retention of visually important trees in urban and rural
locations.”
11.2.12 Policy 113 on Exterior Lighting states:
“That all lighting schemes must:
(a) Avoid dazzle and disturbance of drivers;
(b) Minimise glare and light spillage; and
(c) Create uniformity to avoid shadowed areas.”
11.2.13 Policy 114 relates to Historic Parks and Gardens. It states,
"Development will not be permitted where it would result in the loss of any historic park or
garden or harm to its historic structure, character, principal components or setting."
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Draft Dacorum Core Strategy, January 2013
11.2.14 The Core Strategy is expected to be adopted in mid-2013. The pre-submission version of the
written document is currently available for reference which was published in October 2011
for public consultation. The List of Proposed Amendments was incorporated in June 2012
prior to the Examination in Public which commenced in early October 2012. Modifications to
the Pre-Submission Core Strategy were published in January 2013. The Core Strategy,
once adopted, will establish the overall pattern of development across the Borough up to
2031. The following policies are relevant to the TVIA.
11.2.15 Policy CS10: Quality of Settlement Design includes the following three relevant instructions:

Deliver landmark buildings at movement and pedestrian gateways and enhance focal
points with high quality architecture;

Preserve and enhance green gateways; and

Protect and enhance wildlife corridors.
11.2.16 Policy CS11: Quality of Neighbourhood Design advises, "within settlements and
neighbourhoods, development should:

Respect the typical density intended in an area and enhance spaces between buildings
and general character;

Preserve attractive streetscapes and enhance any positive linkages between character
areas;

Co-ordinate streetscape design between character areas;

Protect or enhance significant views within character areas;

Incorporate natural surveillance to deter crime and the fear of crime; and

Avoid large areas dominated by car parking.”
11.2.17 The rationale for these two policies makes reference to Dacorum's Spatial Awareness
Framework. This has provided the foundation for the assessment of the impact of this
development on Hemel Hempstead’s townscape (see Appendix F.2).
11.2.18 Dacorum's Spatial Awareness Framework (Figure 11, p73) is a framework to help
developers accord with the vision and the place strategies for towns and large villages in the
borough, the Residential Character and Conservation Area Appraisals, and the character
zones in the Urban Design Assessments. It states; "Developers must consider the
relationship of the proposed development with its location and physical context" by
considering the following relevant points:
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“C. The character of the neighbourhood/urban design zone:

The character appraisal of the neighbourhood pattern;

Typical density;

Key landmarks;

Movement and pedestrian gateways; and

Key views within the settlement.
D. The public and private realm, streets, spaces and movement corridors:

Movement routes of people and wildlife;

Public space network;

Private gardens; and

Green infrastructure.
E. The character of the site:

Street pattern;

Style of buildings;

Building lines and orientation of buildings; and

Materials used.”
11.2.19 The headings listed above have provided the structure for the assessment of the townscape
baseline conditions.
11.2.20 Policy CS12: Quality of Site Design states that:
"On each site development should:
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
Provide a safe and satisfactory means of access for all users;

Provide sufficient parking and sufficient space for servicing;

Avoid visual intrusion, loss of sunlight and daylight, loss of privacy and disturbance to the
surrounding properties;

Plant trees and shrubs to help assimilate softly screen development and softly screen
settlement edges;

Integrate with the streetscape character; and
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
Respect adjoining properties in terms of:
i. Layout;
ii. Security;
iii. Site coverage;
iv. Scale;
v. Height;
vi. Bulk;
vii. Materials; and
viii. Landscaping and amenity space.”
11.2.21 Policy CS25 on Landscape Character states: “All development will help conserve and
enhance Dacorum’s natural and historic landscape. Proposals will be assessed for their
impact on landscape features to ensure that they conserve or improve the prevailing
landscape quality, character and condition and take full account of the Dacorum Landscape
Character Assessment, Historic Landscape Characterisation and advice contained within the
Hertfordshire Historic Environment Record.”
11.2.22 Policy CS26 on Green Infrastructure notes:
“The Green Infrastructure Network will be protected, extended and enhanced.”
It goes on to explain:
“Development and management action will contribute towards:

The conservation and restoration of habitats and species;

The strengthening of biodiversity corridors;

The creation of better public access and links through green space; and

A greater range of uses in urban green spaces.

Open spaces will be managed in accordance with the Council’s Green Space Strategy.”
11.2.23 Policy CS27 relates to the Quality of the Historic Environment. It states: “All development
will favour the conservation of heritage assets. The integrity, setting and distinctiveness of
designated and undesignated heritage assets will be protected, conserved and if appropriate
enhanced. Development will positively conserve and enhance the appearance and
character of conservation areas. Negative features and problems identified in conservation
area appraisals will be ameliorated or removed.”
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11.2.24 Most trees in Conservation Areas are protected if they are over 75mm diameter measured
1.5 metres above ground level.
11.2.25 Policy CS31 on Water Management requires development to include measures to minimise
run-off and “secure opportunities to reduce the cause and impact of flooding, such as using
green infrastructure for flood storage.”
11.2.26 The Hemel Hempstead Place Strategy is included within the Draft Core Strategy (2012) and
has informed the development of the Hemel Hempstead Masterplan 2012 (see below).
Policy CS33: Hemel Hempstead Town Centre states: "New development will a) contribute
fully to the achievement of town centre uses, movement and design principles; and b) meet
relevant opportunities for character zones within the town centre.”
11.2.27 The Place Strategy states: "Developers must consider the relationship of the proposed
development with its character zone and opportunities available." (p.165) Character zones
have been identified to guide regeneration in different parts of the town centre. These are
described further below and have been mapped in Appendix F.1, Figure 11.5.
11.2.28 The Place Strategy advises that The Town Centre Master Plan will provide further guidance
and information particularly on the areas of greatest change and activity.
Draft Hemel Hempstead Town Centre Masterplan 2013
11.2.29 The Hemel Hempstead Town Centre Masterplan was adopted in January 2013. This
masterplan is a Supplementary Planning Document and supports the emerging Core
Strategy. It replaces the Hemel Hempstead Civic Zone Development Brief SPD.
11.2.30 The document splits the town centre into a series of character zones, as defined by the Core
Strategy (Sept. 2012). The site sits in the Gade Zone which is described as containing “a
number of large buildings that are vacant, under-utilised or no longer suitable for modern
requirements. There are also two large vacant sites in the form of the Market Square and
the site of the former ‘Dacorum Pavilion’. Buildings tend to be poorly related to the wider
streetscape and the River Gade, the public realm is generally poor and both east-west and
north-south pedestrian and cycle routes are inadequate.” (Para 2.9.1)
11.2.31 The draft masterplan indicates that there is a significant opportunity to regenerate this zone
through the delivery of new educational and civic facilities, alongside retail and residential.
The key strength of the zone is considered to be its location near the heart of the town
centre. The masterplan specifically states that there is opportunity to deliver a new foodstore
to the north zone as part of a comprehensive redevelopment scheme.
11.2.32 The extent to which the character zones presented in the Town Centre Masterplan can be
used to inform the baseline of the TVIA is presented in Section 11.3.44.
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Methodology
11.3.1
The methodology for this TVIA has been based upon best practice guidance presented in
the Guidelines for Landscape and Visual Impact Assessment (GLVIA) (Second Edition,
2002). Updated guidance in the form of Guidelines for Landscape and Visual Impact
Assessment 3rd Edition (GLVIA3) (LI & IEMA 2013) was published in April 2013. However,
as this assessment was started using GLVIA2 it has been completed in line with this edition
in line with guidance from the Landscape Institute. However, due regard has been given to
the third edition where pertinent.
11.3.2
The third edition contains more current guidance on methodologies for assessing townscape
and has been referred to when necessary.
Overview of the TVIA Methodology
11.3.3
The GLVIA Guidelines (2002) recommends that a townscape and visual impact assessment
is based upon:

A baseline study to present the elements and characteristics of the existing townscape
and visual resource; how these combine to form the existing scenario and perceived
value of this resource, which is determined through a desktop review of relevant
documentation;

An appreciation of the proposed development at key stages in its lifespan;

An assessment of the potential effects of the development, which is established through
presenting the extent or magnitude of change expected to affect existing resources;

An evaluation of the significance of the proposed change based on consideration of the
magnitude of the change and the sensitivity to change of the existing townscape and
visual resource;

A description of mitigation measures that could feasibly be incorporated into the
proposed development scheme to avoid, reduce, remedy or offset any negative effects
on existing resource arising from the proposed development; and

A summary of the residual impact based upon the incorporation of mitigation into the
site.
Structure of This Section
11.3.4
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As noted in Section 11.1.3 of this chapter and as advised in the GLVIA Guidelines, the
separate but interlinked nature of townscape and visual information requires each subject to
be assessed separately. This chapter initially describes approaches and issues relevant to
both townscape and visual assessments before each methodology independently.
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TVIA Study Area
11.3.5
The GVLIA Guidelines (2002) advise “the area of study for the visual assessment may
extend to the whole of the area from which the development is visible.” This area is referred
to as the ‘visual envelope’38 of the development. The visual envelope is also referred to as a
Zone of Theoretical Visibility, a Zone of Visual Influence 39 or the view-shed of a
development. Identifying the visual envelope of a proposed development site provides a way
of estimating receptors (physical landscape resources or viewer groups that will experience
change) within the surrounding area that are mostly likely to experience change in the view.
11.3.6
Best practice guidance suggests that the visual envelope of a development is established
using three main methods:

Undertaking a desk-top study of maps, which is generally then clarified during a field
assessment;

The development of a computer-generated model, which is especially useful for wider
scale studies; and

Agreeing the primary area of concern with the client or regulatory body.
11.3.7
An initial scoping study of Hemel Hempstead suggested that the visual envelope of this
development would be included within a 500m study area radius from the site boundary.
However, further discussions with Dacorum Borough Council on 7th November 2012
determined that the study area for the TVIA should be stretched in northerly and southerly
directions and constricted to the east and the west. The agreed study area for the TVIA is
shown in Appendix F.1, Figure 11.1.
11.3.8
Further consultation was undertaken with Dacorum Borough Council to determine the scope
of the visual assessment. This is described in Section 11.3.70.
Baseline Conditions
11.3.9
A number of studies and documents have been consulted in order to collect baseline
information. These are referred to in the references section of this chapter, Section 11.8.1.
11.3.10 In addition, aerial photographs of the site and surrounding environs supplied by Google
Maps were used.
11.3.11 Planning designations effect the interpretation of both townscape and visual assessments
and therefore are presented as a general section before the two separate baseline scenarios
are detailed.
Field Survey
38
39
Definition: Extent of potential visibility to or from a specific area or feature
Definition: Area within which a proposed development may have an influence or effect on visual amenity.
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11.3.12 The field survey for the TVIA was undertaken on Thursday 8th November 2012. The weather
conditions were clear with some patchy cloud cover and good visibility.
Scenarios for Assessment
11.3.13 Effects are assessed at the following stages of the project:

Construction and first occupation: This is when construction is on-going and where some
parts of the site may be occupied while construction continues elsewhere, likely to be in
2015.

At completion: This refers to the completion of all phases in the construction, anticipated
at to be at the end of 2014.

Establishment: This takes account of mature vegetation and takes place fifteen years
from completion in 2029.
11.3.14 Informed judgements are made by making reference to available drawings, photomontages
and visuals produced as part of this assessment.
11.3.15 Environmental effects will be classified as either permanent or temporary, where appropriate.
Permanent changes are those which are either irreversible (e.g. permanent land take), will
last for the foreseeable future (e.g. a new permanent building) or will have environmental
effects (potentially of a different nature) for the foreseeable future (e.g. tree planting).
Temporary effects describe changes that are in place for between 0 and 3 years.
Cumulative Impact
11.3.16 Cumulative effects that may result from the proposed development along with other major
developments. However, no committed development has been identified for consideration in
pre-application discussions with the DBC. Therefore, there is no need for assessment of
cumulative effects.
11.3.17 It should be recognised that the town centre masterplan sets out a comprehensive scheme
for the redevelopment of this area. This means that there is the potential for the character of
the area to change substantially in the future. However, no planning applications have yet
been received for other phases of redevelopment and therefore there is no detail on which to
base a cumulative assessment.
Assessment of the Scale of Townscape and Visual Impacts
11.3.18 The scale of an impact is determined by combining ‘sensitivity’ assessments with the
predicted ‘magnitude of change’ that the proposed development is expected to have.
11.3.19 The two variables (sensitivity and magnitude) can be correlated as illustrated in the detailed
townscape and visual methodologies presented. A combination of sensitivity and magnitude
will give impacts which may be severe, major, moderate, minor or not of significance. The
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impacts may then be beneficial, adverse. The impact is classed as ‘not significant when the
development has no discernible effect on the existing resource.
11.3.20 The assessment of significance ultimately relies on professional judgement, although
comparing the extent of the impact with criteria and standards specific to the townscape and
visual resource can guide this judgment.
Mitigation Measures and Enhancement
11.3.21 “The purpose of mitigation is to avoid, reduce and where possible remedy or offset any
significant negative (adverse) effects on the environment arising from the proposed
development.” (p.13. LI&IEMA, 2002) Two types of mitigation exist:

Primary mitigation measures are those which are accommodated within the design
process.

Secondary mitigation measures specifically address the remaining (residual) negative
(adverse) effects of the final development proposals:
1. Avoidance of the issue through the design and construction process;
2. Reduction of the issue when negative effects cannot be avoided. This could be
achieved through making changes to the design proposal;
3. Remediation of negative effects through additional interventions; and
4. Compensation measures could be employed when a negative effect cannot be
mitigated to an acceptable degree. However, it should be noted that in many cases,
it is not possible to truly compensate or replace like with like.
11.3.22 The GLVIA guidance (2002) note that ‘enhancement measures’ are separate to ‘mitigation
measures’. Enhancement measures refer to opportunities for a development site to
contribute positively to its setting. This TVIA includes mitigation methods in Section 11.6.
Residual Impacts
11.3.23 The resultant impact of the scheme on the townscape and visual resource is presented in
this section. The assessment considers the original impact assessment with all mitigation
measures agreed by the developers. The methodology repeats the process of combining
sensitivity with magnitude of change, taking into account that the agreed mitigation
measures alter the assessment of magnitude of change, or sway the nature of the impact
from adverse to beneficial.
Assumption and Limitations
11.3.24 The proposed development site plans illustrate the overall arrangement of infrastructure,
land use, built form, massing, open space and main structural elements of the development.
The assessment and the prediction of impacts during the construction and operation of the
development are based on this information, detailed design drawings and informed
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professional judgement. At the time of the assessment, limited information was available
relating to the construction phase.
11.3.25 This methodology aims to provide an objective, fair and realistic assessment of impacts upon
the townscape and visual resource. Professional judgement has been drawn upon, where
necessary to inform the assessment.
11.3.26 The outline element of the scheme is for a new educational building to be used by West
Herts College. An indicative building footprint, car parking provision and roadside tree and
vegetation planting has been included in the general project description. It has been
assumed that the buildings will be three storeys and 13m high for the purpose of this
assessment. The visuals presented in Appendix F.1 (Figures 11.7-12) differentiates
between proposals associated with the outline and detailed planning application.
11.3.27 It should be noted that the visual envelope of a development is a theoretical method of
identifying possible receptors. It does not guarantee that all receptors within the envelope
will be affected by change. The extent to which development is effected is determined
through further assessment methods.
11.3.28 Baseline conditions have been established using existing assessments, available
documentation and field assessment. Site surveys were undertaken during autumn 2012.
At this point in time, some but not all deciduous trees had lost a significant proportion of their
leaves. Winter assessments are beneficial because they present a visual baseline that
represents maximum visibility. Making assessments when deciduous vegetation is visible
allows for the appreciation of the contribution that trees make to townscape.
11.3.29 The assessment of visual effects has been undertaken from outside properties and
assumptions have been made about the types of room existing and about the types and
importance of views obtained from these rooms.
11.3.30 Visuals have been created following the methodology described above. Where existing
buildings are to be removed, the replacement view has been created based on professional
judgement and photographic material collected during field studies.
11.3.31 Not all footpaths or streets have been walked. Assumptions have been made about the
extent and degree of importance of views relative to the streets as a whole, based on
assessment of sample routes/locations.
11.3.32 A separate assessment has been undertaken to consider potential impact on built heritage in
Chapter 16 of the ES. In this TVIA, designated features are considered as an indication of
receptor sensitivity. Particular attention has been given to Grade II* and Grade I Listed
Buildings. Where there are many such heritage assets available in any given area, an
indicative range of visual and user experiences have been selected for assessment.
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Townscape Assessment Methodology
11.3.33 This section presents the methodology used to assess the potential impacts of the
development on townscape and is based upon the best practice guidance listed in the
references provided in Section 11.6.
11.3.34 The assessment of the character of a place is the basic tool for understanding landscape
and townscape (LI & IEMA 2002). Townscape character assessment describes and
assesses the key components, features and characteristics that make up the various
landscape types found within the study area. Assessment of the impact of the development
on townscape and landscape character at a range of relevant scales is a crucial element of
the landscape impact assessment.
Establishing Baseline Conditions
11.3.35 The following methodology described in the GLVIA (2002) has been followed to determine
the baseline conditions for the townscape assessment.

Desk-top study of relevant information, existing character assessments and planning
designations (see studies listed in Section 11.9). Planning designations provide
important indicators of the level of value or importance society places upon the effected
place.

A field survey and completion of a field report to clarify character area boundaries
identify key features and receptors and ascertain townscape condition, both generally
and in relation to key components of the townscape.
11.3.36 The results of the baseline study are described in Section 11.4 of this document. Figures
11.6 a-d present findings photographically.
Selection of Townscape Receptors
11.3.37 Townscape receptors are selected by considering if a development has the potential to
physically change its nature either directly or indirectly. Organising the townscape into
character areas is a basic tool for understanding its composition.
11.3.38 Strategic level character assessments exist at a national and regional scale. These have
been broadly summarised within this chapter in order to guide suggestions for mitigation. In
addition, a general description of the general character of the town has been provided. At a
local level, The Draft Hemel Hempstead Town Centre Masterplan (2012) describes seven
established town centre character zones.
11.3.39 A site visit was conducted to establish which of the character zone’s townscape attributes
would be affected either directly or indirectly by the proposed development. It was
established that the following town centre character zones could be potentially affected by
the proposed change:
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
Gade Zone (the character area within which the site resides)

Hemel Old Town (abuts the site boundary to the NE)

Original Marlowes Zone (abuts the site boundary to the E)

Jellicoe Water Gardens (abuts the Gade Zone to the SW)
11.3.40 It was established that views from the Hospital Zone are almost entirely screened by existing
vegetation and built form and therefore would not be considered in the TVIA.
11.3.41 The residential slopes to the West of Leighton Buzzard Road and parts of Gadebridge Park
would be indirectly affected by the proposed development and therefore should be
considered in the TVIA. Character areas have been established to represent these areas
and the rationale for this is provided below.
11.3.42 ‘The Western Slopes’ describes the area bounded by Warner’s End Road to the North,
Leighton Buzzard Road to the east, and Cemetery Hill to the south. The western boundary
is formed of the easternmost edge of Lockers Park and Heath Lane Cemetery. The common
characteristics of this area are its:

Sloping landform40 falling steeply in places towards the River Gade;

Mainly residential land use with architecture varied in age, style, quality and condition;
and

Contiguous street pattern in relation to topography, urban grain and distribution of
gardens and open space.
11.3.43 Finally, it was established that there was a need to assess the character of ‘The Proposal
Site’ itself as a separate entity within the Gade Zone.
11.3.44 In summary, six townscape receptors have been established in the form of character areas
for assessment. These are listed below and mapped in Figure 11.5 (Appendix F.1).
40

The Proposal Site;

Gade Zone;

Hemel Old Town;

Original Marlowes Zone;

Jellicoe Water Gardens; and

The Western Slopes.
Definition: Combinations of slope and elevation that produce the shape and form of the land
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11.3.45 Strategic level assessments will provide the context for this more detailed set of receptors.
Recording Townscape
11.3.46 Townscape, like landscape, is a combination of both cultural and physical characteristics or
components, which give rise to patterns that are distinctive to particular localities and help to
define a ‘sense of place’. Townscape character is an interaction of influences including
topography, land use and management, historic and cultural associations together with built
form and its relationship to its surroundings.
11.3.47 In order to develop a relevant method for undertaking the field survey, a number of sources
from best practice guidance and local policy have been consulted and the content compared
and collated. The draft third edition the GLVIA (LI & IEMA, 2012) note factors of particular
concern in a townscape assessment. As described in Section 11.2, an awareness of the
spatial and design qualities of place are explicit in Dacorum Borough Council’s local policy,
particularly in Dacorum’s Spatial Awareness Framework (11.2.18). The Urban Design
Compendium (2000) is widely accepted as best practice guidance for understanding and
designing townscape. The compendium’s ‘Character appraisal inventory’ provides a useful
reference for further comparison.
11.3.48 The result of this comparison is available in Appendix F.2. The headings and themes for
analysis are used in the presentation of the townscape baseline in Section 11.4.
11.3.49 For each townscape receptor a selection of photographs representing townscape
characteristics are presented in Appendix F.1, Figure 11.6 (a-d).
Assessing Townscape Sensitivity
11.3.50 Sensitivity is judged as the extent to which a townscape can accept change of a particular
type and scale without unacceptable adverse effects on its character. Level of sensitivity will
vary with the:

Quality of the existing resource;

Value placed on the existing resource ;

Condition of the existing resource;

Level of compatibility in terms of existing land use, pattern and scale of the townscape,
visual exposure and character;

Extent to which the proposal contributes to townscape character;

Extent to which a particular element could be replaced; and

Scope for effective mitigation in character with the existing townscape.
(adapted from LI&IEMA 2002 p.87)
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11.3.51 In order to establish townscape quality41, sensitivity and condition, it is important that any
relevant planning designations are presented as part of the baseline study.
11.3.52 Based on Table 11.1 and in reference to guidance and precedent provided in LI&IEMA
2002, townscape sensitivity42 can be categorised on the following four point scale.
Table 11.1: Townscape Sensitivity definitions
Level of
Sensitivity
Description
Very High
Internationally or nationally recognised townscape (such as AONB, World
Heritage Site, SSSI) of exceptional quality and condition with a large number of
memorable townscape features deemed to be worthy of conservation in current
state. Elements are not replicable or replaceable. The proposal must be highly
compatible with existing character or rarely visible.
High
Regionally or locally designated townscape of high quality (such as a Local
Nature Reserve), good condition and distinctive in character. Some elements
within the townscape are irreplaceable. The townscape can accommodate
compatible proposals. Some temporary change could be accommodated.
Medium
Locally recognised but undesignated townscape of medium quality with some
distinguishing features. Some townscape resilience and capacity due to
diversity of character. Potentially degraded in places. Tolerant of some change
and in terms of land use, pattern, scale and character of the townscape. The
proposal could be reasonably visually distinctive.
Low
Unrecognised and undesignated townscape of low quality and condition.
Incongruous in character and potentially tolerant of substantial change without
loss of valued elements and capable of accommodating much needed
restorative measures.
Potential Townscape Effects and Magnitude of Change
11.3.53 A proposed development could affect townscape by either:

Directly changing the physical nature of the existing townscape fabric for example the
removal or introduction of new townscape elements such as buildings, roads, pathways
and vegetation; or

Altering the townscape character of the immediate or adjacent area.
11.3.54 Scenarios for assessment during the project’s lifespan and the duration of the impact are
assessed in accordance to the general guidance provided in Section 11.3.13.
11.3.55 This contributes to assessment of magnitude of change. Magnitude of change describes the
degree of change that a townscape receptor is expected to receive. In the assessment, the
likely nature and magnitude of potential changes to individual townscape elements and
characteristics are described together with the potential consequential effect on townscape
character. Factors that are considered in assessing the magnitude of change (either
beneficial or adverse) include:
41
Definition: Based on judgements about the physical state of the landscape, and about its intactness, from
visual, functional, and ecological perspectives. It also reflects the state of repair of individual features and
elements which make up the character in any one place
42
Definition: The extent to which a landscape can accept change of a particular type and scale without
unacceptable adverse effects on its character
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
The extent to which the change (removal/ addition) of landscape features alters the
townscape character;

The extent of the area over which the effect is evident;

The duration of the effect (permanent/ temporary); and

The effectiveness of the mitigation proposed.
11.3.56 Based on Table 11.2 and in reference to guidance and precedent provided in LI&IEMA
2002, magnitude of change can be categorised on the following five point scale:
Table 11.2: Townscape Magnitude of Change definitions
Magnitude of
Change
Description
Very High
A major and permanent change to the physical fabric of townscape elements
and character either over an extensive area.
High
A sizable and permanent change to the physical fabric of townscape character
and features. Change will affect a significant proportion but not all of the
character area or a very intensive change over a more limited area.
Medium
Moderate change to the physical fabric of townscape character and features in a
localised area of the character area. The change could have an impact for a
limited time (e.g. between 0 – 3 years)
Low
A relatively small change (in terms of footprint or scale) or a temporary alteration
to the physical fabric of townscape character and features or a change that does
not affect the physical fabric of the site but influences views experienced from it.
Negligible / no
change
No noticeable change / virtually imperceptible in townscape character.
Assessing the Significance of Townscape Impacts
11.3.57 The scale of an impact is determined by the combination of the ‘sensitivity’ of the townscape
setting or visual receptor and the predicted ‘magnitude’ of the impact or change that the
proposed development would have. The two variables (sensitivity and magnitude) can be
correlated as illustrated in Table 11.3. All impacts are significant unless they are ‘not’ and
the level of significance is indicated in the table below. A description of the nature of the
significance of the development on townscape is provided in Section 11.3.58.
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Table 11.3: Significance of Townscape Impacts Matrix
Magnitude of change
Rating
Townscape Sensitivity
High
Low
Medium
No
change
Very High
Not significant
Not significant
Not significant
Not significant
Low
Minor
Minor – Moderate
Moderate
Moderate-Major
Medium Minor – Moderate
Moderate
Moderate-Major
Major
High
Moderate
Moderate-Major
Major
Major-Severe
Very
High
Moderate-Major
Major
Major-Severe
Severe
Nature of Significant Impacts on Townscape
11.3.58 Impacts can either be seen to be adverse and detrimental to townscape character, or
beneficial. Where adverse and beneficial effects counter-balance one another, the overall
effect can be considered to be neutral. If no change is expected, the impact is not
significant. All effects have some level of significance. More expansive definitions are
provided below (amended from guidance in LI& IEMA 2002).
Defining Townscape Impacts
11.3.59 Table 11.4 defines the main categories of townscape impacts. Assessment outcomes falling
between categories are outcomes in their own right and do not reflect a range or sliding
scale.
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Table 11.4: Definition of Significance: Townscape Impacts
Significance
The Proposed Development Would Result in Effects Which:
Severe
Adverse
Would irrevocably harm or seriously diminish the value of townscape character,
features, and their settings. Proposals of such conflict with the existing topography,
grain, pattern of the townscape so as to be incapable of mitigation.
Major Adverse
Would substantially damage the quality of existing townscape character, features,
and their settings. Such effects would incapable of full mitigation and would
degrade the integrity of a high quality townscape.
Moderate
Adverse
Would have a perceptibly adverse impact on townscape character, features, and
their settings. Proposals are out of scale with the existing topography, grain, scale
and pattern of the townscape.
Minor Adverse
Either temporarily damages, or more permanently is incongruous with the existing
topography, grain, scale and pattern of the townscape.
Not Significant
OR
Neutral
No discernible change to the existing townscape character, features, and their
settings OR where adverse and beneficial effects counter-balance one another.
Minor
Beneficial
Either temporarily improves or is more congruous with the existing topography,
grain, scale and pattern of the townscape.
Moderate
Beneficial
Would appreciably restore and/or enhance existing townscape character, features,
and their settings. Such effects may be capable of further mitigation so as to
maximise the benefits of the proposal.
Major
Beneficial
Would substantially improve the quality of townscape character, features, and their
settings, fundamentally improving previous condition through the introduction of
integrated features and streetscape design which would result in a more
harmonious and distinctive townscape character. Such effects may be capable of
further mitigation so as to maximise the benefits of the proposal.
Severe
Beneficial
The proposed development would be wholly beneficial to townscape character and
would not require further mitigation or enhancement to improve the scheme further.
Mitigation and Residual Impacts
11.3.60 Methodological statements regarding mitigation measures and residual impacts have been
described in Section 11.3.21.
Visual Assessment Methodology
11.3.61 The visual assessment is primarily concerned with changes in what people see as a result of
the proposed development.
Selection of Visual Receptors
11.3.62 Visual receptors refer to viewer groups that will experience change at particular locations.
Visual receptors are selected by considering a range of representative receptors within the
visual envelope of a development site. The term ‘viewpoint’ refers to the location at which
the receptor experiences the view. Viewpoints are established by carefully considering the
range of visual receptors that exists surrounding the site. Best practice guidance suggests
that the range of receptors under consideration should include:
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
Higher ground that provides extensive views of the area;

The full variety of user experiences available in the study area; and

Highly valued or sensitive receptors. This is often represented by the presence of
planning designations such as Listed Buildings, SSSIs etc. Non-designated receptors
should also be represented in the assessment. These may include local visitor
attractions or places with other cultural associations.
11.3.63 Ensuring that the assessment considers the full variety of user experiences available means
that it is important to consider views towards the site:

From different aspects (N, S E and W);

From different townscape character areas;

To represent a range of visual compositions and types of view in relation to the
development (from elevation, focussed views, panoramic views, filtered views);

From various distances around the development;

From public and private receptors;

In relation to different user groups (residents, users of recreational landscapes or
facilities, users of public roads and transport routes, workers); and

The likely frequency of the experience.
11.3.64 This assessment adopted the following methodology for selecting visual receptors for
assessment as recommended by best practice guidance.
11.3.65 Undertake an initial desk-top study to document designated and protected landscapes and
features and scope out receptors that could represent a variety of user experiences.
11.3.66 Complete a site visit to:

Visit the site and look out from it to determine if there are any noteworthy prominent
viewpoints to be considered; and

Identify any additional principal receptors such as footpaths, viewpoints, feature
buildings that may be considered.
11.3.67 Select a number of principal receptors that represent the full range of experiences and
valued features for further analysis.
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Potential Visual Receptors Visited With No Views of the Site or Development
11.3.68 The receptors in Table 11.5 were considered potentially sensitive to change and were visited
to establish the level of consideration required in the assessment. The development was
considered to have no direct or indirect impact on the following receptors. Therefore this
assessment will not consider these receptors further.
Table 11.5: Screening of Potential Visual Receptors
Approximate
Location in
Relation to the
Site
Other comments
Scheduled
Ancient
Monument
Minimum
distance: 105m
Direction: N
The development is heavily screened
from the setting of the charter tower by
existing buildings and vegetation.
109 and 80 High
Street
(355553) and
(355573)
Grade II* Listed
Buildings
representative of
views from the
northern end of
High Street
Minimum
distance: 358m
Direction: N
Views towards the site area completely
screened by existing buildings.
The Old Bell &
Kings Arms
(355534) and
(355531)
Grade II* Listed
Building and
representative of
views from the
middle section of
High Street
Minimum
distance: 265m
Direction: N
Views towards the site area completely
screened by existing buildings.
Grade II* Listed
feature
Minimum
distance: 55m
Direction: NE
The development would have no impact
on the immediate setting of the railings.
Grade II* Listed
building
Minimum
distance: 290m
Direction: W
The slightly reduced elevation, oblique
angle of the property and significant
surrounding vegetation would prevent
views towards the site although this site
is on property and so a detailed
assessment was not completed.
Receptor
Reason for
Choice
Designated Potential Receptors
Charter Tower
(1005260)
6-8 Queensway
(433739)
Lockers on Bury
Hill (355508)
Non-designated Potential Receptors
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Gadebridge Park
Public Park,
Minimum
frequently used by distance: 100m
pedestrians and
Direction: N
cyclists
Lockers Park
Public access to
some parts of the
park
Minimum
distance: 225m
Direction: W
Mature trees, adjacent housing and the
sloping landform housing prevent views
towards the development.
Astley Road
Road receptor,
pedestrian
receptors using
the pavements
Minimum
distance: 225m
Direction: W
Views are directed up and down the road
and are mainly blocked by other
residential development. Residential
properties are located at right angles to
the view.
Cemmes Court
Road
Road receptor,
residential
receptors
Minimum
distance: 180m
Direction: W
Views towards the site are blocked by
residential properties on the opposite
side of the road.
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Mature trees, existing buildings and The
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Receptor
Reason for
Choice
Approximate
Location in
Relation to the
Site
Other comments
Alexandra Road
Road receptor,
residential
receptors
Minimum
distance: 80m
Direction: W
Views towards the site are blocked by
residential properties on the opposite
side of the road.
11.3.69 As a result of this process, 13 viewpoints were established for assessment. These are
described in detail in Section 11.4 of this chapter. The viewpoint locations are illustrated on
Appendix F.1 Figure 11.3 along with representative photographs for each.
Consultation on Viewpoints
11.3.70 Consultation with Dacorum Borough Council on November 6th 2012 indicated the following
six key viewpoints that should be looked at in detail in this assessment (see Appendix F.1,
Figure 11.3):

Viewpoint 2: Old Lloyds Bank (ALH House);

Viewpoint 7: From the southeast corner of Gadebridge Court on Warners End Road;

Viewpoint 9: Leighton Buzzard Road on Riverside path – just north of the residential
development;

Viewpoint 10: 100 Bury Road;

Viewpoint 12: Old Marlowes House; and

Viewpoint 13: Pedestrian walkway adjacent to Hamilton House.
NB: The viewpoint numbers listed here link to the visual baseline conditions assessment
presented in section 11.4.
11.3.71 The detailed assessment of the views agreed with Dacorum Borough Council means that
views from these receptors have:

Been photographed in accordance with Landscape Institute Advice Note (2011); and

Had computed generated visuals developed to represent proposed changes in the view
(see below for more methodological information on both of these matters).
11.3.72 Dacorum Borough Council also expressed an interest in receiving a Computer Generated
Image to represent views from the top of the NCP car park on Marlowes. This viewpoint
does not represent views commonly experienced by much of the public and car park users.
For this reason, this viewpoint has not been included within this assessment but has been
generated for information only.
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Recording Views
11.3.73 For the six viewpoints to be assessed in detail, photographs were taken with a digital SLR
camera with a 50mm equivalent lens in accordance with LI Landscape Institute Advice Note
(2011) by Architecture Interiors Location Photography who followed the methodology
presented below:
“Cameras used: Monorail camera (Arca Swiss F-compact Metric 6 x 9), a Leaf 75 digital
camera back (33mpixel, sensor size 48 x 36mm) and Schneider prime lenses (usually a
38mm XL, giving a 62 degree angle of view). The camera has built-in spirit levels, and
produces a greatly superior image with a 95mb (6666 x 4992 pixels) digital file to the
imprecision inherent in SLR cameras and zoom lenses. The camera is tripod-mounted and
set in position.
Methodology: A spirit-level or plumb line is used to mark an image from the centre of the lens
(being the point of focus) to the ground in order to mark that point with spray paint, or place
the camera-centre over a recognizable point on the ground, such as the intersection of
paving stones or the corner of a man-hole cover. The marked point and camera set-up are
photographed with a separate camera; the time of day, lens used and the height from ground
to the centre of the lens is recorded.”
11.3.74 The following information was determined by a surveyor from Landmark Surveys:

Precise location 12 figure OS grid reference, measured in the field, using GPS;

Viewpoint altitude in metres above Ordnance Datum (m A.O.D) interpolated from
DTM/OS mapping;

Viewing height in metres; and

Distance and bearing to the development.
11.3.75 Landmark Surveys produced the following methodology:
“PS survey control was established using a Leica TCRP 1205 with the ATX1250 attachment
which utilises the licenced Leica RTK 'SmartNet' network internet connection. Once control
was established remote points within the photographs were observed using the Leica TCRP
1205 reflectorless distance measurement capability. All observations were then downloaded
and processed in Liscad to provide final OS National Grid Coordinates of the camera shot
locations and the photograph remote points.”
11.3.76 For all other viewpoints, views were recorded using a digital camera and stitched together for
to inform the assessment.
11.3.77 The following information is described to record the baseline conditions for each
assessment:
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Receptor reference and description;

An approximate location of the receptor in relation to proposal site;
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
The reason for selecting the receptor;

Description of the existing view; and

Assessment of receptor sensitivity.
Assessing Visual Receptor Sensitivity
11.3.78 The assessment of visual receptor sensitivity is dependent on a number of variables which
include:
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
The relative distance between the receptor and the site; at greater distances, individual
changes in the townscape accommodate a decreasing proportion of the overall view and
less detail is perceived, diminishing potential impact;

The receptor’s orientation towards the development; direct views from receptors aligned
to the site will provide more frequent, open views in comparison to the oblique views that
could be available from receptors angled away from the site. Views from the front door
and façade of buildings are usually more sensitive than those experienced from upper
floors or rear elevations;

The activities associated with the receptor and the extent to which a focus on the view
itself is an important part of an associated activity. For example, more sensitive
receptors include residential receptors or users of places where the view is intrinsically
associated with the quality of that place. Less sensitive visual receptors include people
engages in outdoor sports, people travelling through the area or people at work, whose
attention is likely to be focussed on other activities;

The level of value associated with the receptor; designated or locally valued visual
receptors are more sensitive in their nature;

The number of people experiencing the view; receptors used by more people are more
sensitive than those used by few;

The frequency of exposure; receptors used more often are more sensitive than those
used rarely;

The speed of movement of the viewer; people exposed to a particular view for longer will
have more exposure to changes within it. For example, view from a designated
viewpoint or a residential property is more sensitive than a transient view that is
experienced as part of a journey, especially when travelling at speed. Receptors walking
along a pathway are more sensitive to change than those driving along a motorway;

The quality of the townscape within which the receptor resides. A higher quality
townscape is more sensitive to change than a lower quality townscape; and
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
The cultural significance of the viewpoint. Including its appearance in guidebooks and
tourist maps, or the strength to its relationship with cultural and historical associations
but also represented by planning designations.
11.3.79 In order to comment on cultural significance, it is important that any relevant planning
designations are presented as part of the baseline study.
11.3.80 Based on Table 11.6 and in reference to guidance and precedent provided in LI&IEMA
2002, visual sensitivity can be categorised on the following four point scale.
Table 11.6: Visual Sensitivity Definitions
Level of
Sensitivity
Description
Very High
Important and highly utilised views from within nationally or internationally
designated townscapes or adjoining townscape with focal point or orientation in
the direction of the site. Views from or within the setting of a Grade I or II* listed
building.
E.g. Exceptional and iconic views from townscape features of recognised historic
importance. Widely visited sites important for tourism and urban identity
High
Important static (including residential) or well visited open views with orientation
in the direction of the site. Views from or within the setting of a Grade II listed
building. May have a regional or local designation.
E.g. Focussed views from a well-used footpath within a high quality townscape
setting.
Medium
Everyday and ordinary views in the direction of the site experienced by many or a
more locally important view, or a view enjoyed by some local people or
experienced by many. Views could be from undesignated areas of medium
townscape quality.
E.g. Commonplace and/or partially interrupted views from retail/commercial or
public services. May include views from moving vehicles or local parks.
Low
Transient and unimportant views in the direction of the site, rarely utilised by
individuals in that location or views from poor quality townscapes. Partially
interrupted and/or distant views from undesignated areas. Views experienced
while travelling at speed.
E.g. Unspecified and/or sporadic views from and within the setting of industrial or
derelict areas. May include views from fast moving vehicles.
Potential Visual Effects and Magnitude of Change
11.3.81 A proposed development could affect views directly changing the physical nature of the
existing townscape fabric present within the view. The degree of change expected from
each viewpoint is referred to as magnitude of change. In the assessment, the likely nature
and magnitude of potential changes to views are described. Scenarios for assessment
during the project’s lifespan and the parameters used to describe potential duration of the
impact are assessed in accordance to the general guidance provided in paragraph 11.3.13.
Factors that are considered in assessing the magnitude of change in views (either beneficial
or adverse) include:
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The extent to which the change (removal/addition) of townscape features alters the view;

The extent of the view that will be effected;
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Contribution to the skyline; the extent to which the proposal breaks the horizon. For
example, if the proposal is placed against a backdrop, visual impact is diminished;

The degree of contrast or integration of any changes with the existing or remaining
landscape components – form, mass, height, colour and texture;

The extent to which movement of vehicles and light reflection changing with movement
draw the eye, increasing impact. Static neutral coloured, sympathetic forms diminishes
adverse impact;

The relative size of the proposal in relation to the surrounding townscape;

The duration of the effect (short / medium / long term / intermittent / permanent /
temporary); and

The scope for effective mitigation in character with the existing townscape.
11.3.82 Based on Table 11.7 and in reference to guidance and precedent provided in LI&IEMA
2002, magnitude of chance can be categorised on the following five point scale:
Table 11.7: Visual Magnitude of Change Definitions
Magnitude of
Change
Description
Very High
The proposed development permanently becomes the single or collectively
dominant new feature breaking the horizon with a high degree of contrast with the
setting.
High
The proposed development becomes an important and immediately obvious new
feature within the view due to the distinct contrasting nature of the proposal in
relation to its setting.
Medium
The proposed development is visible and identifiable within the view; readily
detected by the majority of viewers. The development contrasts less with its
setting or forms a discrete proportion of the view.
Low
The proposed development constitutes a minor change within the view however it
is largely contiguous, is neither framed nor prominent and therefore not readily
noticeable.
Negligible / No
Change
Nothing or very little of the development or associated work or activity is
discernible.
Computer Generated Images
11.3.83 To inform the assessment of magnitude of change, six of the viewpoints, as selected by
Dacorum Borough Council have been developed into computer generated images.
Rendered views have been provided in Appendix F.1, Figures 11.7-11.12.
Assessing the Significance of Townscape Impacts
11.3.84 The scale of an impact is determined by the combination of the ‘sensitivity’ of the townscape
setting or visual receptor and the predicted ‘magnitude’ of the impact or change that the
proposed development would have. The two variables (sensitivity and magnitude) can be
correlated as illustrated in Table 11.8. All impacts are significant unless they are ‘not’ and
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the level of significance is indicated in the table below. A description of the nature of the
significance of the development on townscape is provided in Section 11.3.85.
Table 11.8: Significance of Visual Impacts Matrix
Visual Receptor Sensitivity
Magnitude of Change
Rating
Low
Medium
High
Very High
No
Change
Not Significant
Not Significant
Not Significant
Not Significant
Low
Minor
Minor – Moderate
Moderate
Moderate – Major
Medium Minor – Moderate Moderate
Moderate – Major
Major
High
Moderate
Major
Major – Severe
Very
High
Moderate – Major Major
Major – Severe
Severe
Moderate-Major
Nature of Visual Impact
11.3.85 Impacts can either be seen to be adverse and detrimental to the visual resource, or
beneficial. If no change is expected, the impact is neutral. Unless neutral, all effects are
significant. More expansive definitions are provided below (amended from guidance in LI&
IEMA 2002).
Defining Visual Impacts
11.3.86 Table 11.9 defines the main categories of townscape impacts. Assessment outcomes falling
between categories are outcomes in their own right and do not reflect a range or sliding
scale.
Table 11.9: Definitions of Significance: Visual Impact
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Significance
The Proposed Development Would Result in Effects That:
Severe
Adverse
The proposed development would result in invasive and clearly incongruous visual
effects which would permanently result in the loss of, or disrupt, key views from (or
of) an important sensitive receptor.
Major Adverse
The proposed development would result in a substantial deterioration in, or loss of,
the existing view. Detrimental visual effects incapable of full mitigation.
Moderate
Adverse
The proposed development would result in an obvious, permanent deterioration of
the existing view.
Minor Adverse
The proposed development would result in visual effects that constitute a
conspicuous or temporary deterioration in the existing view.
Not Significant
OR
Neutral
The proposed development would result in a situation analogous to the current
situation. No clear adverse or beneficial impacts resulting from visual effects OR
where adverse and beneficial effects counter-balance one another.
Minor
Beneficial
The proposed development would result in visual effects that constitute a
conspicuous or temporary improvement in the existing view.
Moderate
Beneficial
The proposed development would result in an obvious, permanent improvement of
the existing view.
Major
Beneficial
The proposed development would result in a substantial improvement to the
existing view and positively influence the character of the receiving townscape
feature.
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Significance
The Proposed Development Would Result in Effects That:
Severe
Beneficial
The proposed development would wholly change the nature of the view having a
dramatic and substantial positive impact on the receptor. Further mitigation or
enhancement would not be required.
Mitigation and Residual Impacts
11.3.87 Methodological statements regarding mitigation measures and residual impacts have been
described in Section 11.3.21.
Baseline Conditions
11.4.1
This section includes a review of designated sites, which as explained in Section 3 of this
chapter, contribute to the appreciation the relative quality, value and sensitivity of receptors.
Following on from this, more detail on the existing townscape and visual resource is
presented.
Designated Sites
11.4.2
All relevant designated sites have been mapped in Appendix F.1, Figure 11.2 during the
commentary provided below and where relevant, English Heritage reference numbers have
provided in the form of 'EH' followed by a number.
National Level Designations
Conservation Areas
11.4.3
The very northern part of the site overlaps with The Hemel Hempstead Old Town
Conservation Area, which takes in the entire surviving part of the medieval core of the town
and includes small sections of Gadebridge Park along its southern and western edges. The
Conservation Area boundary does not extend eastwards from the High Street to quite the
same extent as the Hemel Old Town character zone as defined in the Hemel Hempstead
Town Centre Masterplan (2012). The Conservation Area Appraisal for this area was
published for consultation in April 2012. The appraisal states, “Generally, the buildings in the
Old Town are well maintained and in a reasonable condition with some notable exceptions.”
(p.39) A list of planned enhancements for the Hemel Hempstead Old Town conservation are
included in the appraisal.
Listed Parks and Gardens
11.4.4
Hemel Water Gardens is the only site within the study area listed on the 'Register of Historic
Parks and Gardens of Special Historic Interest in England' within the study area.
11.4.5
Hemel Water Gardens (EH1001710) is a Grade II Listed Park and Garden comprising a
series of public gardens running along the River Gade along a north-south axis. Designed
by Geoffrey Jellicoe as part of the new town development of Hemel Hempstead, the water
gardens are predominantly civic in character and contain established vegetation, a distinctive
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landform to the northern end, an open pool and fountain to the south. The water gardens
occupy approximately 3.5 hectares within the town centre.
11.4.6
Design company HTA’s prepared a Draft Design Development Report on the Water Gardens
July 2012) which includes the following summary that relates to the current condition of the
gardens:
“Fifty years following completion, the structure of the Gardens has remained remarkably
intact. The canal, bridges, weirs, circulation and Formal Flower Gardens are largely
unaltered.
However, their character has been significantly impacted upon and the sense of ‘romance’
described by Jellicoe has been lost. This has occurred through changes in maintenance,
piecemeal encroachment and interventions, changes of materials, furniture, tree planting,
loss of views and a weakening in the relationship to the town centre.
The Gardens are perceived as neglected and unsafe. Whilst many people walk through the
park on their way to the town centre, active use remains low.” (p.5)
Scheduled Ancient Monuments
11.4.7
The Charter Tower, Hemel Hempstead (EH1005260) is located in the south-east corner of
Gadebridge Park. The Charter Tower is the entrance to the original Bury House, which used
to reside here. It now marks the entrance to Hemel Hempstead’s Walled Gardens.
Listed Buildings
11.4.8
Table 11.10 shows Listed Buildings organised by the baseline townscape character areas
defined in Section 11.3.37. English Heritage Reference numbers have been provided for
Grade I and II* Listed Buildings. Listed Buildings within the study area are mainly located in
the townscape character area of Hemel Old Town. These are provided in order to provide
an indication of receptor sensitivity.
11.4.9
It should be noted that for assessments of impacts on listed buildings the evaluation of
landscape quality, value and sensitivity refers to the building or monument in its landscape
setting and views, not to the building itself.
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Table 11.10: Listed Buildings According to Relevant Town Centre Character Areas as Listed in Section 11.3.37
The Old Town
Grade I Listed Buildings
Church of St Mary on High Street (355562)
Grade II* Listed Buildings
109, High Street (355553)
80, High Street (355573)
The Old Bell Public House, Figtree Hill (355534)
The King's Arms Public House, George Street (355531)
Numbers 6 and 8 Wrought Iron Front Railings (433739)
The Bury, 1, Queensway (433615)
Grade II Listed Buildings
There are 54 Grade II Listed Buildings located within Hemel Old Town,
mainly clustered around High Street and Queensway, including the Old
Lloyds Bank building and the Old Town Hall.
Original Marlowes Zone
Grade I Listed Buildings
None
Grade II* Listed Buildings
Old Marlowes House, Midland Road (355615)
Grade II Listed Buildings
There are 10 Grade II Listed Buildings located within the Original
Marlowes Zone including The Carey Baptist Church.
The Western Slopes
Grade I Listed Buildings
None
Grade II* Listed Buildings
Lockers on Bury Hill (355508)
Grade II Listed Buildings
There is one Grade II Listed Building within this character area which
is Lockers Cottage on Bury Hill.
Tree Preservation Orders
11.4.10 Tree Preservation Orders are applicable to 6 trees located within the site.
mapped in Appendix F.3 11.4 and are listed below:

These are
Located in planters, to the south of the Marlowes Methodist church on Dacorum Way:
1 x Lawson cypress (T106 on TCP); and
1 x Western red cedar (T107 on TCP).

Located halfway along and a little north of Dacorum Way:
2 x Cherry (T160 and T162 on TCP); and
2 x Sycamore (T158 and T159 on TCP).
11.4.11 The Hemel Hempstead Old Town Conservation Area includes the southern verge of
Queensway. The trees along this edge are therefore protected as described in Section
11.2.24. It is assumed the protection includes the following trees on Queensway:
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
T125 London Plane;

T126 London Plane;
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
T127 Hornbeam;

T129 Common Lime;

T30 Norway Maple;

T131 Small-leaved Lime;

T132 Small-leaved Lime;

T133 Norway Maple;

T138 London Plane;

T139 Common Pear;

T141.1 Holly;

T141 Sycamore; and

T140 Common Pear.
11.4.12 A copy of the aboricultural impact assessment and plans, completed by Aboricultural
Solutions (October 2012) is provided in Appendix F.3.
Townscape Baseline
11.4.13 The townscape character of the study area can be considered at a variety of different scales.
Existing studies outlining landscape and townscape character have been summarised below.
This, together with field surveys provides the baseline conditions for the townscape impact
assessment.
Contextual Studies
11.4.14 The following studies provide a contextual background to Hemel Hempstead in relation to its
character. This is relevant in understanding the context of the study area and providing
background information for use when developing mitigation measures.
National Character Areas
11.4.15 National Character Areas (NCAs) divide England into 159 distinct natural areas and are
prepared by Natural England. NCAs replace Joint Character Area (JCAs) and Countryside
Character Area descriptions (1998-1999 by the Countryside Agency). Revised profiles for all
159 Character Areas are due to be published by April 2014. In the meantime, Key Facts and
Data are available for many character areas and archived content is available in the interim.
The site falls within NCA 110 ‘The Chilterns’. The characteristics of this area relate mainly to
the landscape rather than townscape of the region and so are not considered further in this
assessment.
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Regional Character Areas
11.4.16 Landscape East, a regional Landscape Forum published the region’s Landscape Character
types43 online in 2011. The website contains an interactive map that links to general
descriptions of landscape character types. Hemel Hempstead is greyed out as an Urban
Area. The three landscape character types adjacent to the town are:

Wooded Plateau Farmlands: For the most part this is a settled, early enclosed landscape
with frequent ancient woods, associated with a rolling, in places undulating glacial
plateau, dissected by numerous shallow valleys;

Wooded Chalk Valleys: Steep sided, wooded valleys which penetrate the surrounding
upland plateau, becoming shallower with only seasonal watercourses in their upper
parts. Larger valleys have permanent watercourses, often associated with river
meadows; and

Valley Meadowlands: Flat, low lying valley floors supporting a pastoral land use,
associated with notable watercourses/rivers. Generally unsettled, with occasional areas
of carr woodland and gravel extraction lakes, or ancient meres.
11.4.17 Regional Landscape Character Areas44 relate to the contextual landscape (see Appendix
F.1, Figure 11.4). More detailed townscape character areas (see below) provide a more
appropriate baseline for this assessment however some points listed here may guide
mitigation and enhancement proposals.
Site Context
Local Landscape Character Areas
11.4.18 In 2002, Dacorum Borough Council commissioned a district-wide landscape character
assessment which was an extension of the Hertfordshire Country Council and St Albans
District Council assessments. Thirty landscape character areas were established within the
Dacorum District, which excluded key urban settlements, including Hemel Hempstead. Of
the thirty district areas, ‘High Gade Valley’ is most pertinent because it abuts the northern
edge of Hemel Hempstead at Queensway, which defines the northern edge of the site (see
Appendix F.1, Figure 11.4). The characteristics of the area are:

Steep valley slopes;

Long views along the open valley;

Traces of downland scrub and woodland;
43
Definition: A landscape type will have broadly similar patterns of geology, landform, soils, vegetation, land use,
settlement and field pattern discernible in maps and filed survey records
44 Definition: The distinct and recognisable pattern of elements that occurs consistently in a particular type of
landscape, and how this is perceived by people. It reflects particular combinations of geology, landform, soils,
vegetation, land used and human settlement. It creates the particular sense of place of different areas of the
landscape.
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
Clustered settlement along watercourse;

Wet woodlands and grazing meadow;

Sweeping arable fields;

Floodplain and wetland vegetation;

Ancient settlement; and

Ornamental nurseries and associated planting.
11.4.19 An assessment of the character area’s condition and strength of character resulted in the
general recommendation to conserve and strengthen the characteristics of this area. The
following recommendations are relevant to mitigation and enhancement recommendations:

Promote integrated land use, management and development within catchments in order
to conserve and enhance river corridors as important and characteristic open
landscapes;

Encourage the reversal of habitat fragmentation and the creation and improvement of
habitat links to create eco-corridors;

Survey and manage parkland and veteran trees for biodiversity value;

Ensure new planting is encouraged to maintain age diversity. Ensure landscape
improvements respect the historic context of existing features and the form and
character of parkland and gardens. Ornamental species should only be used to replace
damaged or over-mature specimens, where appropriate; and

Conserve and enhance the distinctive character of traditional settlements and individual
buildings by promoting the conservation of important buildings and high standards of
new building or alterations to existing properties, all with the consistent use of locally
traditional materials and designed to reflect the traditional character of the area.
The Study Area and its Setting
11.4.20 The site has been described in Chapter 3 of the ES. Around the site, the land rises to the
east reaching a high point of 141m AOD approximately 1km due east of the site on Adeyfield
Road. The landform rises to the west but less steeply than the east, rising to 134m AOD,
approximately 1.6km west of the site on Galley Road, Gadebridge. Directly to the north and
south of the site the landform is consistent with the valley floor within which the site lies with
only nominal changes in level for a considerable distance.
Historical Context of the Site and Study Area
11.4.21 The area around Hemel Hempstead has evidence of human activity from pre-historic times
to the present day. The upland clays and rivers were the main attractions for early settlers in
the area. The town was known as Henamsted or Hean-Hempsted (High Hempstead) in
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Anglo-Saxon times and, in 1140, the parish Church of St. Mary was built, and now
recognised as one of the finest Norman parish churches in the country.
11.4.22 During the medieval period the hamlet developed between the mills at Bury and Piccotts End
on the banks of the River Gade. The settlement was located within an agricultural estate
owned by the monastic college of the Bon Hommes at Ashridge until the dissolution of the
monasteries in 1539. Following the medieval period, Hemel Hempstead prospered due to
the corn trade and several buildings from the 16th to 18th centuries still survive along the High
Street.
11.4.23 In the 1800’s the site contained water-cress beds along the banks of the River Gade. In
1890, a Wesleyan Methodist Chapel (now in use as Marlowes Methodist Church) was built in
the south-east corner of the site in a Gothic Geometrical style.
11.4.24 After the Second World War, proposals were drawn up for the building of a New Town
attached to Hemel Hempstead, one of several in the country. The southern part of Marlowes
was included within a modern shopping boulevard. Also built in the post-war period was the
Civic Centre campus for Hemel Hempstead and the new Dacorum College of Further
Education.
11.4.25 In 1961 work commenced on the new Dacorum College, with the first buildings opening in
1963. In 1991 Dacorum College merged with Watford College and Cassio College to
become West Herts College.
Townscape Receptors and Sensitivity Assessment
11.4.26 The nature of the townscape in these areas has been documented in accordance with the
series of headings derived from the methodology presented in Appendix F.3 and described
in Section 11.3. In Appendix F.1, Figures 11.6 presents a series of accompanying
photographs of notable characteristics.
11.4.27 For each character zone the following information is presented:

Baseline information is presented as described above;

The sensitivity of each townscape character area is ascertained by reviewing it
according to the criteria listed in Section 11.3.50.
The Proposal Site
11.4.28 The ‘Proposal Site’ (as a character area) baseline conditions and sensitivity assessment are
presented in Table 11.11. Photographs are presented in Appendix F.1, Figure 11.6A.
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Table 11.11: Townscape Baseline: The Proposal Site
The Proposal Site
Relationship to the Site
Direct: This character area related exactly to the site’s boundaries.
Baseline Conditions
Setting and Context
Context/setting of the
urban area and its
relationship to the wider
landscape and
townscape
The site is located in the centre of Hemel Hempstead between the main
old town and new town centre. The urban grain surrounding the Proposal
Site is generally tighter and smaller in all directions except to the south,
which contains developments with similar footprint. One notable
exception to this is the ASDA foodstore located to the south-east of the
Proposal Site in the Original Marlowes Zone.
Landform, level
changes, topographic
features
The topography of the site slopes from Marlowes down towards the River
Gade. This level change is currently accommodated through terracing
and sloping pathways.
Patterns of land use
The site is currently used for civic and educational purposes.
Presence of particular
heritage assets
The Hemel Hempstead Old Town Conservation Area encompasses the
northernmost boundary of The Proposal Site along Queensway.
Form
Layout and scale of the
buildings
Rectilinear blocks generally between three to five stories high. Elevations
range between10 and 50m in length.
Typical density
Medium density with landscape pavilions creating a patchwork of green
spaces between the buildings.
Building lines and
orientation
Buildings are generally parallel or at 90 degrees to Marlowes. Buildings
along the north and west sides of the site are oriented away from main
roads, where there are no active frontages. Buildings are set out in a
grid-like pattern.
Building age / period
Civic and educational building. All c.1960 except for Marlowes Methodist
Church, which was built in 1890.
Building condition
Materials look dated and appear in poor condition.
Building materials used
Glass, concrete slab and paving, dark brick work, polycarbonate and
plastic panelling, timber arbours painted white
Movement and Experience
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Street pattern
Three main roads serve as boundaries to the site: Marlowes to the east,
Queensway to the north and Leighton Buzzard Road to the west.
Access and
connectivity
Access is generally by way of Dacorum Way, an access road serving the
college and civic centre car parks. Pedestrian connectivity through the
site is generally poor. Access is limited to the use of a number of minor
and convoluted pathways. There is a pedestrian bridge across the River
Gade located approximately 65m south of Queensway. This appears to
be mainly used by college users. Access to the River Gade is poor with
only one riverside path connecting to Combe Street.
Movement and
pedestrian gateways
The Queensway / Leighton Buzzard Road Roundabout acts as a gateway
into Hemel Hempstead Town from the north and north/west.
The Queensway / Marlowes junction is an important gateway between
the old and new town and is notes in the Draft Hemel Hempstead Town
Centre Masterplan (2012).
Public space network
The civic square outside the Civic Centre on Marlowes is a sizeable
although generally featureless paved area. The generous pavements
along Marlowes adjacent to and to the north of the square allow
pedestrians space to slow down and pause.
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Street furniture and
Lighting
Street furniture is generally dated and functional and although
coordinated in colour and style, fails to create a strong sense of place.
To the north of the site, the public realm becomes increasingly cluttered
with low quality railings, bollards, seating and signage. The Dacorum
College signs are newer and are more effective. Lighting around the
periphery of the site is provided by street lights on columns approximately
12m high. Within the site itself, small scale lamp posts illuminate the
public realm and are approximately 6-7m high. Light spilling from
buildings will be generally more noticeable in winter and will be largely
effected by building opening times.
Key landmarks
Within the character area: Marlowes Methodist Church is prominent along
the eastern edge of The Proposal Site.
Outside of the character area: The spire of St Mary’s Church is a key
focal point and can be seen for some distance, predominantly from the
west but also in some views from the east and south.
The Carey Baptist Church and the restored Georgian White House are
distinctive buildings on the periphery of the study area, visible from within
it.
Key views within the
area
Many views are within the site have a short range and are interrupted by
buildings. More open views generally look out over areas of car parking.
Views along Leighton Buzzard Road open out over the grassland
adjacent to The River Gade, which is itself largely hidden from view.
Views to the west include the wooded backdrop of garden and parkland
vegetation in the western slopes of Hemel Hempstead. Occasional
glimpses of St Mary’s church spire are available from Dacorum Way. The
mature trees in the site create a visual connection between this character
area and Gadebridge Park.
Visual barriers
The college building to the north-west and the civic buildings to the southwest block views along the River Gade.
Scenic quality
Generally low within The Proposal Site but improved by the presence of a
significant number of mature trees.
Green and Semi-Natural Infrastructure
River corridors and
streams, ponds, lakes
rivers
The River Gade, which runs north south through the site before meeting
the River Bourne located 1.5km to the south. Throughout the Proposal
Site, the river remains approximately 1.5m in width.
Private gardens
None present.
Green Infrastructure
The River Gade and its banks is an important, continuous landscape
feature within the Proposal Site that connects Gadebridge Park to the
north with the Jellicoe Water Gardens to the south. The improved
grassland and mature trees adjacent to the river creates the impression
of a riverside park (although very few pathways provide access to this).
The setting of the college buildings within a patchwork of green spaces
supports a number of mature trees.
Variations in nature and
location of vegetation
Small, ornamental plantings along Marlowes and in the Civic Square add
some diversity. There are 27 different species of 133 trees within the
Proposal Site. 21 of the trees have been rated as category A trees in the
Arboricultural Report produced by Arboriculture Solutions (2012). There
are 77 category B trees. Six are protected with Tree Preservation Orders
as noted in Section 11.4.10. In addition, the trees located within the
Hemel Hempstead Old Town Conservation Area are likely to be
protected.
Sensitivity Rating
Based upon the baseline condition presented above, the Proposal Site has been assessed as
having a LOW townscape sensitivity level.
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The Gade Zone
11.4.29 The baseline conditions and sensitivity assessment for the Gade Zone is presented in Table
11.12. Photographs are presented in Appendix F.1, Figure 11.6a.
Table 11.12: Townscape Baseline: The Gade Zone
The Gade Zone
Relationship to the site
Direct: The site is located within this character.
Baseline Conditions
Setting and Context
Context/setting of the
urban area and its
relationship to the wider
landscape and
townscape
This character zone is located between the main old town and new town
centres and to the east of Marlowes.
Landform, level
changes, topographic
features
The topography of the character zone slopes from Marlowes down
towards the River Gade. The slope is noticeably steeper to the north of
the character zone. The landform slopes subtlety north-south down the
river valley.
Patterns of land use
Mainly civic and educational buildings. There is a small residential
development on the south-western corner of the area. To the south of
the character area, retail outlets surround the market square.
Presence of particular
heritage assets
The Hemel Hempstead Old Town Conservation Area encompasses the
northern most boundary of the character zone along Queensway.
The Jellicoe Water Gardens is located directly south.
Form
Layout and scale of the
buildings
Rectilinear blocks generally between three to seven stories high.
Elevations range between10 and 50m in length.
Typical density
Medium sized buildings are scattered through this character area creating
a series of spaces of a similar size.
Building lines and
orientation
Buildings are commonly well set back from the street, from which they are
separated by wide verges and mature trees. Building entrances are
orientated towards the street although the architectural detailing makes
little reference to this effect.
The new (approximate late 20th century) residences are two story, red
brick homes set back from the main road.
Building age / period
All date from between 1950 and 1960 and are in the modernist style
except for the Marlowes Methodist Church which was built in 1890 in a
Gothic Geometrical style and is a notable feature in the area.
Building condition
Dated in style and generally in a poor condition.
Building materials used
Glass, concrete slab and paving, dark brick work, polycarbonate and
plastic panelling, timber arbours painted white, painted floorscapes,
abstract concrete forms, green galvanized street furniture.
Movement and Experience
Street pattern
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Three main roads serve as boundaries to the site: Marlowes to the east,
Queensway to the north and Leighton Buzzard Road to the west. Combe
Street is a secondary road providing east-west access and access to the
bus station.
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Access and
connectivity
There is trodden path along the eastern edge of the River Gade although
there are no crossings over it for a stretch of approximately 500m. I t is
not possible to walk all the way to Gadebridge Park, along the river, due
to the existing college campus on the northwest corner of the area.
There are a number of routes that cut across the college campus. These
are complicated and are not straightforward to use.
Movement and
pedestrian gateways
The Queensway / Leighton Buzzard Road Roundabout acts as a gateway
into Hemel Hempstead Town from the north and north/west.
The Queensway / Marlowes junction is an important gateway between
the old and new town and is notes in the Draft Hemel Hempstead Town
Centre Masterplan (2012)
The south-eastern corner of the market square is noted as a pedestrian
gateway in the Masterplan (DBC 2012).
Public space network
Medium sized open spaces are distributed throughout the character area.
Some contain predominantly grass and trees (especially in the college
campus), others are paved (for example the Market Square), and some
are used for parking. Although a generous proportion of the character
area comprises open space, many are under-used, inaccessible and of a
low environmental quality.
Street furniture and
Lighting
Street furniture is generally dated and functional and although is
coordinated in colour and style, fails to create a strong sense of place.
Light spilling from buildings will be generally more noticeable in winter
and will be largely effected by building opening times. Parts of the
character area seem poorly lit.
Key landmarks
Within the character area: Marlowes Methodist Church is prominent along
the eastern edge of the character area.
Outside of the character area: The spire of St Mary’s Church is a key
focal point and can be seen for some distance, predominantly from the
west but also in some views from the east and south.
The Carey Baptist Church and The restored Georgian White House are
distinctive buildings on the periphery of the study area and are visible
from within it.
Key views within the
area
Long and uninterrupted views along the Leighton Buzzard Road and
Marlowes are available. The view east along Queensway has a sense of
grandeur created by the avenue of mature deciduous trees (to the south)
and Yews (to the north) that flank the road. Many views are within the
character area have a short range and are interrupted by buildings. More
open views generally look out over areas of car parking or civic squares.
Views along Leighton Buzzard Road open out over the grassland
adjacent to The River Gade, which is itself largely hidden from view.
Views to the west include the wooded backdrop of garden and parkland
vegetation in the western slopes of Hemel Hempstead. Occasional
glimpses of St Mary’s church spire are available from Dacorum Way. The
mature trees in the site create a visual connection between this character
area and Gadebridge Park.
Visual barriers
The college building to the NW and the civic buildings to the SW block
views along the River Gade. The dominant civic buildings to the south of
the character area are physically and visually impermeable.
Scenic quality
Generally low within the character area although the presence of mature
trees improved this.
Green and Semi-Natural Infrastructure
Document1
River corridors and
streams, ponds, lakes
rivers
The River Gade, which runs north south through the site before meeting
the River Bourne located 1.5km to the south. Throughout the site, the
river remains approximately 1.5m in width.
Private gardens
None present.
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Green Infrastructure
The River Gade and the open space adjacent to it create a ribbon of
green that is weakened by college and civic development punctuating it
and the lack of paths and river crossings. The greens within the college
campus create a patchwork of secondary green spaces throughout the
area, many of which contain mature trees that soften the buildings and
provide a strong sense of green when viewed from the outside of the
area. The mature willows suggest the presence of the river at a distance.
Variations in nature and
location of vegetation
Small, ornamental plantings along Marlowes and in the Civic Square add
some diversity but are not of particularly high quality. See above for more
detail.
Sensitivity Rating
Based upon the baseline condition presented above, the site has been assessed as having a LOW
townscape sensitivity level.
Hemel Old Town
11.4.30 The baseline conditions and sensitivity assessment for the Gade Zone is presented in Table
11.13. Photographs are presented in Appendix F.1, Figure 11.6b.
Table 11.13: Townscape Baseline: Hemel Old Town
Hemel Old Town
Relationship to
the site
Hemel Old Town flanks the site to the north and north-east.
Baseline Conditions
Setting and Context
Context/setting
of the urban
area and its
relationship to
the wider
landscape and
[townscape]
This character zone is the northern most character zone identified in the Draft
Hemel Hempstead Town Centre Masterplan (2012). The area to the southwest of
the Old Town has undergone significant change in the last 50 years resulting in a
fragmented and poor quality townscape that responds poorly to the historical grain
of the town.
Landform,
level changes,
topographic
features
Land slopes gently downhill on High Street from north to south. Steeper slopes lie
to the east and although initially, there is a more sudden step down to the west,
land slopes more gently down to the River Gade through Gadebridge Park.
Patterns of
land use
The main businesses include professional services, high quality specialist shops
and a strong evening economy with a variety of pubs, restaurants and cafes.
Presence of
particular
heritage
assets
There are many Listed Buildings in this character area including Grade 1 Listed St
Mary’s Church and the Charter House, which is a scheduled Ancient Monument,
all of which are located within the Hemel Hempstead Old Town Conservation
Area.
Form
Document1
Layout and
scale of the
buildings
Generally two to three story buildings.
Typical density
and grain
A tight grain largely in keeping with medieval boundary plots.
Building lines
and orientation
Buildings predominantly face High street and Queensway. Frontages vary in
width. The roofscape is varied in height, pitch and style creating much visual
interest and character. The extent to which buildings lines are set back from the
kerb varies along the street and sometimes from building to building.
Building age /
period
Predominantly dating from the 16th to 18th centuries.
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Building
condition
The area of the character area to the north of Marlowes has less integrity and is
more dilapidated than the area around High Street.
Building
materials used
There are some examples of well-crafted detailing throughout this character area
including; the herringbone lead-work of the Church of St Mary’s spire, the elegant
curved windows of many of the buildings, the herringbone brick-work of the
buildings, the staggered and varied roofscape, the chequerboard stone and flintwork on the church, the heavy gables that sometimes overhang the street and the
wall-mounted lighting.
Movement and Experience
Document1
Street pattern
Queensway, High Street and Marlowes are the three most dominant thoroughfares
in the character area. Queensway and Marlowes are wider streets and more
heavily trafficked. Marlowes is the widest street with generous pavements,
occasional mature trees and bus stops. High Street is more pedestrian friendly
with raised pedestrian crossings along its length.
Access and
connectivity
There are a number of small streets, alleyways and paths leading east and west
from High Street, often through alleyways between the buildings. The level of
permeability here is good.
Movement and
pedestrian
gateways
The Queensway / Marlowes junction is an important gateway between the old and
new town and is notes in the Draft Hemel Hempstead Town Centre Masterplan
(2012) The prominence of the gateway weakens towards the west due to
changing building alignment mainly in the Gade Zone, cluttered street furniture,
poor quality materials and some degraded building frontages.
One of the main pedestrian and cycle entrances into Gadebridge Park is located at
the northern tip of Marlowes.
Public space
network
The public space network is largely associated with Gadebridge Park, St Marys
Church grounds and area's the streetscape. Small spaces and wide corners along
High street function as small public spaces and provide a place to pause, for
example at the Corn Exchange, near the stretch of buildings set back from the
road to the north of High Street or the entrance to Gadebridge Park.
Street furniture
and Lighting
Street furniture in and around The High Street is carefully located and is generally
of a high quality. Towards Marlowes, street furniture is cluttered, dated and in
some cases, broken.
Key landmarks
The spire of the Church of St Marys is the most dominant local landmark in the
area. The old Lloyds bank is a distinctive building that celebrates the corner
between Queensway and High Street. The charter tower is visible from some
locations within Gadebridge Park. Buildings on the periphery of the study area
and are visible from within it.
Key views
within the area
Key views exist up and down the main thoroughfares within the character area and
include:
The view towards the Old Lloyds Bank building is important within the visual
sequence of the town. The style and detailing of the building suggests the
presence of the historic core of the town.
The view from the Old Lloyds Bank building focuses on the two existing London
Planes, which soften the view, hide the built form behind it and suggest the end of
the old town centre. The backdrop of the view includes the steeply rising slopes of
residential properties. Mature trees soften the view and create a wooded horizon,
helping orientation.
The view south along Marlowes to and from the park is regularly experienced by
pedestrians and is therefore important. The long view contains building of a mixed
character. The Methodist church protrudes into the pavement and serves to break
up the view, creating visual interest along Marlowes and decreasing the perceived
distance between the old and new town.
Views east and west from High Street are characterised by framed views through
alleyways and other architectural features. To the east, views are linear in nature
and are contained by predominantly residential buildings. To the west, views
generally open out to larger spaces and take in the canopies of mature trees. At
the corn exchange, views towards the Church of St Mary’s grounds are framed by
stone arches.
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Visual barriers
The dense grain of the buildings along High Street and the vegetation in
Gadebridge Park inhibits views towards the developments site from most locations
along High Street and in the park itself.
Scenic quality
Generally high to very high. Scenic quality is lower towards the north of Marlowes
due to the incongruous nature of architectural treatments and the variable quality
of the public realm.
Green and Semi-Natural Infrastructure
River corridors
and streams,
ponds, lakes
rivers
The course of The River Gade, runs through the south-western tip of the character
zone to the east of The Bury.
Private
gardens
Private gardens to the west to the east of High Street are visible through archways
and along residential roads. These add texture and variety to the views glimpsed
from High Street.
Green
Infrastructure
Gadebridge Park, the grounds of Church of St Mary's and all adjacent private or
semi-private pockets of green and garden space provide a dominant swathe of
green to the east of this character area. Gardens and street trees on Queensway
characterise the more fragmented Green Infrastructure to the east of High Street.
The area to the southeast of Gadebridge Park is designated Open Land.
Variations in
nature and
location of
vegetation
There is a good level of diversity in this character area. In addition to the elements
of green infrastructure noted above, the character area includes The Walled
Gardens in Gadebridge Park.
Sensitivity Rating
Based upon the baseline condition presented above, the site has been assessed as having a HIGH
townscape sensitivity level.
Original Marlowes Zone
11.4.31 The baseline conditions and sensitivity assessment for the Original Marlowes Zone is
presented in Table 11.14. Photographs are presented in Appendix F.1, Figure 11.6d.
Table 11.14: Townscape Baseline: Original Marlowes Zone
Original Marlowes Zone
Relationship to
the site
Original Marlowes Zone flanks the site to the east / south-east.
Baseline and Conditions
Setting and Context
Document1
Context/setting
of the urban
area and its
relationship to
the wider
landscape and
townscape
This character zone lies on the eastern edge of the centre of the as presented
Draft Hemel Hempstead Town Centre Masterplan (2012). The area, particularly to
the west of this character area has undergone significant change over the past 50
years resulting in a fragmented and low quality townscape with few distinctive
features except for The Marlowes Methodist Church and River Gade.
Landform,
level changes,
topographic
features
To the east of Marlowes, the land rises by approximately 15m, initially steeply and
then at varying gradients towards the brow of the hill at Adeyfield.
Patterns of
land use
The villas along Marlowes appear to be predominantly used as office and
residential properties. Most of the larger shopping units are located away from the
Marlowes frontage.
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Presence of
particular
heritage
assets
One Grade II* Listed Building and ten Grade II Listed Buildings are located in this
area, to the east of Marlowes.
Form
Layout and
scale of the
buildings
Generally two to three story buildings with a few exceptions as noted below.
Typical density
and grain
The buildings within this character area vary in size and footprint. The older
properties (c19) on Marlowes and the residential streets to the east are of a tighter
urban grain. However there are a number of bulkier buildings such as the Asda
foodstore and Maitland House. The seven storey, brick built ‘Maitland House’ and
Marlowes Business Centre is rather incongruous compared to the smaller scale
residences to the north and south.
Building lines
and orientation
The buildings along Marlowes are all oriented towards the main road and are set
well back from the road creating wide pavements.
Building age /
period
The buildings in this character generally age from the 19th century there are a
number of newer buildings such as the 20th century Maitland House.
Building
condition
Some of the villas appear in very good quality and the White House appears to
have been refurbished to a very high standard. Some of the villas require
improvements to their façades.
Building
materials used
Many of the villas and Carey’s Baptist Church are brick built. Some of the higher
quality villas (The White House) are rendered. Old Marlowes House and Little
Marlowes House are brick-built and painted. A variety of different types of brick
have been used. There is a flint-work wall along the frontage of Old Marlowes
House.
Movement and Experience
Document1
Street pattern
The principal street in this character area is Marlowes, which is a wide
(approximately 15m) distributor road that runs throughout the new town top the
east of the River Gade. A network of residential streets connects to Marlowes or
runs perpendicular to it. Pedestrian routes cut through the Marlowe properties to
link to these roads.
Access and
connectivity
Connectivity and permeability is generally good within this character area.
Movement and
pedestrian
gateways
There are no identifiable gateways present within the character area. However,
the threshold between this and surrounding character areas (certainly to the west
and south) is clear due to strong contrasts in building style and scale.
The south-western corner of the market square is noted as a pedestrian gateway
in the Masterplan (DBC 2012).
Public space
network
There is little sizable public space present in this character area bar small,
predominantly hard spaces associated with the shopping area.
Street furniture
and Lighting
Street furniture in and around The High Street is carefully located and is generally
of a high quality. Towards Marlowes, street furniture is cluttered, dated and in
some cases, broken.
Key landmarks
The Carey Baptist Church and The White House are key local (visual) landmarks
in this area, particularly when looking east from other area within the valley.
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Key views
within the area
The view up and down Marlowes is of particular importance. It is wide, open and
linear. It takes in some of the key landmarks and buildings on the eastern side of
town such as the beginning of the Old Town, Marlowes Methodist Church and the
spire of Church of St Mary’s, which is visible over mature parkland trees. To the
south, the new town’s civic centre dominates the view with the shopping district
visible in the distance. Views are available west across the valley from the
western side of Marlowes. College and civic buildings dominate the foreground of
the view, the backdrop of which comprises the rising slopes of west Hemel
Hempstead, which are heavily treed. The trees create a sense of coherence and
positively detract from the mixture of architectural styles present within this
predominantly residential area.
Visual barriers
The north-south orientation of the buildings prevents views west from streets
located to the east of Marlowes.
Scenic quality
Scenic quality is generally low – medium. Although there are some distinctive
buildings present, there is a lack of overall scenic quality around the Marlowes
area created by the mixed architectural styles, disproportionate relationship
between built forma and space, lack of street trees and mixed use of materials.
Green and Semi-Natural Infrastructure
River corridors
and streams,
ponds, lakes
rivers
Non present.
Private
gardens
See below.
Green
Infrastructure
The network of green infrastructure in this character area is almost entirely reliant
on private gardens and their vegetation and the street trees along Marlowes.
These include the two trees with TPOs on Dacorum Way.
Variations in
nature and
location of
vegetation
See above.
Sensitivity Rating
Based upon the baseline condition presented above, the site has been assessed as having a
MEDIUM townscape sensitivity level.
Jellicoe Water Gardens
11.4.32 The baseline conditions and sensitivity assessment for the Jellicoe Water Gardens is
presented in Table 11.15. Photographs are presented in Appendix F.1, Figure 11.6c.
Table 11.15: Townscape Baseline: Jellicoe Water Gardens
Jellicoe Water Gardens
Relationship to
the site
The Jellicoe Water Gardens is located immediately south of the Gade Zone.
Baseline Conditions
Setting and Context
Context/setting
of the urban
area and its
relationship to
the wider
landscape and
townscape
Document1
This character area is located on the lower south eastern edge of the town.
Jellicoe Water Gardens encompasses the whole of the listed Water Gardens area
designed by Geoffrey Jellicoe between 1957 and 1962, running from Combe
Street to Moor End Road.
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Landform,
level changes,
topographic
features
There is a very slight fall from north to south across the character area. Within it,
the river banks are sloped slightly to the river. At the northern end of the gardens,
past Lover’s Walk, the meandering river snakes its way to a circular mound
immediately south of Combe Street.
Patterns of
land use
The water gardens are a public garden. The gardens include a play area to the
north (added in the 1980s), ‘Lovers’ Walk’ to the west, the formal flower garden to
the southwest and the lake to the south.
Presence of
particular
heritage
assets
Hemel Water Gardens (EH1001710) is a Grade II Listed Park and Garden.
Form
Layout and
scale of the
buildings
The scale of the gardens is impressive comprising approximately 3.5 hectares of
the town centre footprint (Water Gardens Study, 2011). This area is divided into a
number of smaller zones or gardens each with their own characteristics.
Typical density
and grain
N/A
Building lines
and orientation
The water garden is laid out on a north-south axis with east west pedestrian routes
cutting across it.
Surrounding built form, especially to the east of the water gardens, is oriented
away from its main axis and fails to compliment it. The existing car park
accommodates a large footprint and occupies a central site in the town although
views to it from the surrounding area are generally well-disguised.
Building age /
period
The gardens were laid out between 1957 and 1962. There have been incremental
changes to the water gardens over the years including the extension of the car
park in the 1980’s, the realignment of the lake to make way for the Moor End
Roundabout, new planting and the new playground.
Building
condition
The water gardens are highly valued and well-used area within the town centre.
The garden’s fundamental qualities are effective; the idea of river that changes in
character from parkland to civic centre, with frequently changing views, a range of
vegetation and frequent crossings. In general though, the gardens require
significant refurbishment and design work is currently in progress.
Building
materials used
The water gardens comprise a simple palette of materials and techniques which
were characteristic of the 1950s – elegant concrete bridges, earth bunds,
concrete-lined water features, simple furniture and a mix of naturalistic and formal
planting. However, much of this has been altered over the years to include a more
functional and less careful approach to the installation of street furniture. The
overall look is now far less elegant and more cluttered in style. Native species are
now generally mixed with ornamental shrubs and trees.
Movement and Experience
Document1
Street pattern
The routes within the gardens are predominantly pedestrian except for access to
the car park. The park is flanked to the east by Waterhouse Street and to the west
by the Leighton Buzzard Road. Combe Street is located to the north of the park
and Moor End to the south. Bridge Street crosses the park though the middle.
Access and
connectivity
The water gardens offer the experience of continuous public space with changing
character areas along its length. Despite its current poor condition, the gardens
are an important and highly valued part of the town’s public realm network and
connect reasonably well to local streets and spaces although are inhibited by the
placement and orientation of surrounding buildings.
The pedestrian routes through the park are characterised by their meandering
nature, which encourages frequently changing views. Regular crossings over
quaint bridges create a sense of rhythm along the park.
Movement and
pedestrian
gateways
The main gateways into the gardens are created by; the mound to the north of the
gardens and the lake to the south. Frequent entrance points into the gardens are
located along its length. There is a clear threshold between the park and the
character areas around it which contain significantly more buildings and areas of
hard landscape.
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Public space
network
The gardens are a continuous area of public space.
Street furniture
and Lighting
Street furniture in and around The High Street is carefully located and is generally
of a high quality. Towards Marlowes, street furniture is cluttered, dated and in
some cases, broken.
Key landmarks
The distinctive landmarks within this character area are the grass mound to the
north of the gardens and the lake with its rock ‘n’ roll sculpture and fountain to the
south. The recently completed retail development to the south is clearly visible
from the southern end of the gardens.
Key views
within the area
Views out from the park are largely contained to the west and are filtered by
mature trees to the east. Views towards Waterhouse Street and beyond a poorly
contained by a weak urban edge created by the backs of buildings. More open
views across the lake exist to the south. Views to the north are more varied,
textured and frequently change as the pathway meanders along the river bank. To
the north, views are increasingly contained by mature vegetation.
Visual barriers
The north-south orientation of the buildings prevents views west from streets
located to the east of Marlowes.
Scenic quality
Scenic quality is generally low – medium. The gardens and the surrounding
buildings require refurbishment. Detailed recommendations were published by
HTA Landscape Design in July 2012.
Green and Semi-Natural Infrastructure
River corridors
and streams,
ponds, lakes
rivers
The River Gade is central to this character area.
Private
gardens
N/A
Green
Infrastructure
The park is an important feature of Hemel Hempstead’s green infrastructure. It
forms a strong, continuous and wide stretch of green space that separates the
town centre from the Leighton Buzzard Road.
Variations in
nature and
location of
vegetation
To the south, planting is minimalistic and clipped. Further north, more variety is
introduced and there are some significant mature trees.
Sensitivity Rating
Based upon the baseline condition presented above, the site has been assessed as having a
MEDIUM townscape sensitivity level.
Document1
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The Western Slopes
11.4.33 The baseline conditions and sensitivity assessment for The Western Slopes is presented in
Table 11.16. Photographs are presented in Appendix F.1, Figure 11.6c.
Table 11.16: Townscape Baseline: The Western Slopes
The Western Slopes
Relationship to
the site
This character area is located immediately to the west of the site.
Baseline Conditions
Setting and Context
Context/setting
of the urban
area and its
relationship to
the wider
landscape and
townscape
This character area is located immediately to the west of Leighton Buzzard Road
stretching up the slopes to Lockers Park. It is bounded by the flats on Bury Hill to
the north and extends south towards station road.
Landform,
level changes,
topographic
features
The land rises 50m, initially steeply towards Lockers Park and then more gently
through the park towards Hammerfield.
Patterns of
land use
The buildings are predominantly residential with business use located towards the
Leighton Buzzard Road. Schools, religious buildings, healthcare centres and
sports centres are located within this character area.
Presence of
particular
heritage
assets
Lockers on Bury Hill (355508) is Grade II * Listed Building. Lockers Cottage on
Bury Hill is a Grade II Listed Building
Form
Layout and
scale of the
buildings
Generally two storey properties although taller buildings and larger blocks are
located towards Leighton Buzzard Road and Warners End Road.
Typical density
and grain
Housing in this area is mid-low density. Houses have substantial gardens and
have been built in terraced, semi-detached and detached configuration. Terraces
and blocks of flats and apartments are occasionally present.
Building lines
and orientation
Buildings are generally oriented parallel or perpendicular to contours.
Building age /
period
The residential core of this character area originates from late 19th century / early
20th century. Newer development, mainly from the latter half of the 20th century is
present towards Leighton Buzzard Road and Warners End Road.
Building
condition
The properties vary in style and character but all appear to be generally in good
condition despite the rear property boundaries between Bury Road and Leighton
Buzzard Road being in generally poor condition.
Building
materials used
There is a mixed palette of materials in this area. Properties immediately adjacent
to the site have red brick or rendered walls which are mediocre in quality and
condition and contribute poorly to the character of the town. Century House and
former Police Station, which was built from red-brick in 1895 and now contains
apartments has more distinctive detailing with stonework lintels around the
windows.
Movement and Experience
Street pattern
Document1
Longer streets follow the contours on a north-south axis. Steeply sloping streets
are located perpendicular to the slope. The main pedestrian pathway connects
Cemmes Court Road with the allotments.
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Access and
connectivity
A number of pedestrian routes support a street network that is generally
permeable and well-connected.
Movement and
pedestrian
gateways
There are no real identifiable points where the layout of buildings and the
distribution of space create a specific gateway into this character area however,
the threshold between this and surrounding landscape and townscape is created
by Gadebridge Park to the north, Lockers Park to the west, semi-natural
landscape to the south and the increased scale of the streets and buildings of the
new town development to the east.
Public space
network
The character area contains Bury Road allotments and parts of Locker’s Park are
accessible in places. The local street network provides a connected series of
spaces.
Street furniture
and Lighting
Basic street lighting and signage present.
Key landmarks
Century House, at the corner of the Leighton Buzzard Road and Warners End
Road is a distinctive building in the north east of the character area.
Key views
within the area
Views towards the town centre comprise a perceptible change in scale of the
buildings in the Gade Zone and Marlowes Shopping Centre however individual
buildings are not particularly distinctive. In addition, views into and across the
valley are softened and heavily filtered by the presence of existing mature trees.
The impact of the trees will be reduced in winter when deciduous trees are bare.
Visual barriers
The north-south orientation of the buildings prevents views east from streets laid
out on a north-south axis.
Scenic quality
Scenic quality is generally medium. Some of the residential streets are attractive,
well-proportioned and have well-kept established gardens. There is a good level
of visual contiguity within the character area itself although this becomes diluted
towards the edges.
Green and Semi-Natural Infrastructure
River corridors
and streams,
ponds, lakes
rivers
N/A
Private
gardens
See below.
Green
Infrastructure
The character area has a good network of green infrastructure comprising private
gardens with mature vegetation, the Bury Street Allotments and a number of
school playing fields. Lockers Park is associated with the school however its
contribution to the green infrastructure of the area is significant.
Variations in
nature and
location of
vegetation
See above.
Sensitivity Rating
Based upon the baseline condition presented above, the site has been assessed as having a
MEDIUM townscape sensitivity level.
Visual Baseline
11.4.34 As noted in Section 11.3.69, 13 visual receptors have been identified for inclusion is this
assessment. The nature of each view has been described below. The sensitivity of the
receptor has been ascribed in accordance with the definitions provided in Section 11.3.78.
Discussions with Dacorum Borough Council as described in section 11.3.70 indicated which
views would be worked up into wireframe representations of the development. These views
are cross-referenced with figure numbers in column one of Table 11.17.
Document1
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Table 11.17: Visual baseline
Receptor Reference
and Description
Viewpoint no. 1.
St Marys Church
(355562)
Approx. Location in
Relation to the Site /
Reason for Choice /
Receptor Sensitivity
Description of the Existing View
Direction: NNE
Approximate minimum
distance from site 190m
Grade 1 listed building
Frequently visited
destination in Hemel
Hempstead. Viewpoint
located outside the main
entrance to the church.
Most receptors would be
transient.
Sensitivity: Very high
Views from each of the Church of St Mary’s’ entrances
were assessed including the main entrance into the
churchyard from High Street.
The southern entrance offers views towards the site in the
far distance, through vegetation. The foreground of the
view comprises the churchyard and flint and brick wall. The
upper part of the view includes the rear façades of buildings
on High Street and a single, late 20th century, low rise
residential property. In the centre of the view, there is
significant garden vegetation including mature trees. In the
far distance Maitland House is visible, which is located on
the opposite side of Marlowes to the site.
From the elevated position of High Street, the view is
largely similar to the description provided above but with
much more visual interest in the foreground provided by the
church, the Old Town Hall and the regularly spaced Yews
in the churchyard. These visual features detract from
details visible in the far distance.
Direction: NE
Approximate minimum
distance from site: 105m
Grade II Listed Building and
Viewpoint no. 2
representative of views from
Old Lloyds Bank (ALH the gateway to the old and
House)
new town areas experienced
Grid reference:
by pedestrian and vehicular
E: 505569.277
receptor and representative
of views experienced by
N: 207682.911
people working in nearby
Viewing altitude:
buildings.
90.131m
The view is experienced
See Figure 11.7
frequently and by many
pedestrians and drivers
using Queensway.
Sensitivity: High
The view is initially bounded on both sides by the two story
buildings on Queensway. The varied shapes, frontages
and roof pitches of the buildings together with associated
signage and ironmongery create much visual interest in the
foreground of this view. Queensway itself dominates the
central foreground. The road leads the eye west towards
the two existing London Planes, which partially filter views
towards the existing single storey college building (located
at a slightly lower elevation than the street). Higher college
buildings are set back from the road.
Buildings along Queensway used mainly for retail and
service industries omit light. Street lights are also present.
Signage and street furniture creates a cluttered feel to this
important town centre node. The residential slopes of West
Hemel Hempstead form the backdrop of the view. Mature
trees in gardens and Lockers Park create a wooded
horizon.
Direction: N
Approximate minimum
distance from site: 35m
Viewpoint no. 3
Grade II* Listed Building in
The Bury – main
close proximity of the
entrance in the centre development
of the south façade.
View experienced by a few
people using the building.
Sensitivity: High
The view from The Bury is largely contained by the row of
existing Yew trees on Queensway. The lower half of the
view comprises The Bury’s lawn and boundary brick wall,
which appears to be of a similar age to the building.
The close proximity of the Yew trees almost completely
blocks views to the existing low-rise college buildings. The
upper canopy of the existing deciduous trees on
Queensway is visible over the tops of the Yew trees.
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Approx. Location in
Relation to the Site /
Reason for Choice /
Receptor Sensitivity
Description of the Existing View
Direction: N
Approximate minimum
distance from site: 29m
Receptor in frequent use by
pedestrian receptors.
Designated open land.
Sensitivity: Medium
The view from the park entrance is aligned with Marlowes.
To the left-hand side of the view, the Old Town’s buildings
are prominent in the fore and mid-ground. The retail outlets
on the east side of Marlowes are approximately 9m high (at
the ridge).
The existing college with its wide verges and network of
mature trees is visible to the centre and left-hand side of
the view. The three north-eastern-most existing buildings
along the western frontage of Marlowes are approximately
3.8m, 3.5m and 10m in height from north to south.
Marlowes Methodist church (approximately 10.5m high at
the ridge) is identifiable in the middle of the view in the far
distance. The detailing of the building is largely screened
by existing vegetation, the location of which, half-way down
Marlowes is a mid-point between the old and new towns.
The form of Maitland House the horizon of the left-hand
side of Marlowes. In the foreground, the presence of
cluttered and dilapidated street furniture detracts from the
quality of this view.
Viewpoint no. 5
Gadebridge Park.
Western entrance
Direction: NNW
Approximate minimum
distance from site: 20m
Receptor in some use by
pedestrian and vehicular
receptors in close proximity
to the site
Sensitivity: Low
The prominent features of this view include:

The gardens of Bury Lodge;

The vehicular entrance to Gadebridge Park; and

The coniferous screening on the north-western
corner of the college site.
The existing college buildings are visible behind the
Western Red Cedars. The buildings are single storey in
the foreground. Higher buildings, (c. 10m high) are visible
in the mid-ground of the view through the trees. Mature
deciduous trees (Willow, Sycamore and Norway Maple
etc.) stand prominent against the lower canopied
coniferous species. The entrance to Gadebridge Park
lacks prominence and is in poor condition.
Viewpoint no. 6
Century House
The prominent features of this view include:

The Leighton Buzzard Road / Queensway /
Warners End Road junction, roads and
roundabout which is planted with Prunus ssp;

The college and civic buildings on the Leighton
Direction: NW
Buzzard Road frontage;
Approximate minimum

Mature trees throughout the site, especially in the
distance from site: 60m
centre of the view; and
Representative of a receptor

The line of Western Red Cedars opposite the
in frequent use by vehicular
Gadebridge Park entrance.
and pedestrian receptors.
The
site
is a central feature within the view. The Cedars
Key town centre gateway
and mature deciduous trees hide much of the existing
Sensitivity: Medium
buildings to the north of the site. The Bury is visible to the
left-hand side of the view. The college and civic buildings
to the left-hand side of the view look dated and in poor
condition. There is a car park between the Western Red
Cedars and the college buildings.
Receptor Reference
and Description
Viewpoint no. 4
Gadebridge Park.
Eastern entrance
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Approx. Location in
Relation to the Site /
Reason for Choice /
Receptor Sensitivity
Description of the Existing View
Viewpoint no. 7
From the southeast
corner of Gadebridge
Court on Warners
End Road
Grid reference:
E: 505205.635
N: 207654.499
Viewing altitude:
93.964m
See Figure 11.8
Direction: NW
Approximate minimum
distance from site 152m
Residential receptor +
vehicular and pedestrian
receptors at elevation in
relation to the site
Sensitivity: Low
The residential receptor is located at an oblique angle in
relation to the site.
The view from the road is direct and is at an elevated
position in relation to the site. This view is experienced at
slowing speeds when travelling in an easterly direction.
The view is flanked on both sides by roadside vegetation,
trees and occasional residential buildings – more so to the
left hand side of the view than to the right. The road itself
occupies much of the foreground.
The site is visible in the centre of the view in the middle to
far distance. Existing college buildings are visible beneath
the canopies of existing mature Willows. This detracts from
the presence of the buildings and creates a strong sense of
green.
The existing hierarchy of built form comprises the single
storey college building in the foreground and a higher
college building in the mid-ground (approximately 10m in
height).
The eastern slopes of Hemel Hempstead create a
backdrop to the view. The winding nature of the road
means that this particular view is only experienced
momentarily by drivers and pedestrians.
Viewpoint no. 8
78 Bury Road
The residential receptor is located at an oblique angle in
relation to the site. It looks directly across towards another
residential property but has oblique views of the site from
Direction: WNW
the front garden and the ground and upper floors. The view
Approximate minimum
is dominated by the grove of mature Ash trees between the
distance from site 45m
end of Bury Road and Leighton Buzzard Road. In summer,
Residential receptor and
the canopies of these trees block many of the views to the
indicative of views from the site. In winter views remain filtered but are more open in
rear of properties along Bury character.
Road
The site accommodates the central visual plane in the
Sensitivity: Low
middle distance. It is possible to identify the north-eastern
college car park and low rise buildings and the mature
Willows along the River Gade.
Viewpoint no. 9
Leighton Buzzard
Road on Riverside
path – just north of
the residential
development
Grid reference:
E: 505372.035
N: 207328.341
Viewing altitude
83.97m
See Figure 11.9
The view from this point is orientated north. Views ahead
and to the right take in the site.
From this viewpoint, the view is largely formed of the
generous grass verge separating the River Gade and the
Leighton Buzzard Road. Mature informally planted (or selfDirection: SW
seeded) deciduous trees provide visual interest, break up
Approximate minimum
views and encourage a meandering trodden pathway. The
distance from site: 20m
River Gade, which is narrow at this point, is visible in the
foreground. Its sunken elevation encourages it to quickly
Pedestrian receptor
experienced at slow speeds. disappear from view. Its presence is suggested by the
rougher vegetation along its banks and mature Willow
Vehicular receptor
experienced at fast speeds. trees. To the right of the view, the large, red-brick civic
centre car park is an unattractive and dominant feature.
Infrequently used
College buildings are visible straight ahead in the mid-far
Sensitivity: Low
distance, in amongst the trees, blocking views to
Gadebridge Park.
The Leighton Buzzard Road and the properties on the
rising slopes further west are visible to the left hand side of
the view.
Receptor Reference
and Description
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Receptor Reference
and Description
Viewpoint no. 10
100 Bury Road
Grid reference:
E: 505318.128
N: 207375.192
Viewing altitude:
84.292m
See Figure 11.10
Viewpoint no. 11
Water Gardens North
Document1
Approx. Location in
Relation to the Site /
Reason for Choice /
Receptor Sensitivity
Description of the Existing View
Direction: W
Approximate minimum
distance from site: 40m
Static, residential receptor
directly overlooking the site
and slightly elevated in
relation to it.
Sensitivity: High
This receptor presents a ‘worst-case scenario’ situation for
other residential receptors on the street although it is the
only receptor with such a direct view of the development.
Receptors will experience this view on a daily basis.
The 2-3 storey college buildings and associated car-parking
on Dacorum Way and the existing red-brick multi-storey
car-park of the DBC offices dominate the mid-ground. The
buildings are separated by areas of grass and to the right
hand side of the view; mature deciduous trees on both
sides of the Leighton Buzzard Road create a filtering effect.
The surface car park of the college is particularly noticeable
from this viewpoint due its location at a higher elevation to
the River Gade
In the centre of the view, the mature deciduous trees of
Gadebridge Park create a soft horizon, which is punctuated
by the spire of Church of St. Mary’s. To the left-hand side
of the view, residential properties and their boundary
fencing accommodate the foreground.
Direction: S
Approximate minimum
distance from site: 121m
Grade II Listed Park and
Garden experienced mainly
by pedestrian receptors.
Sensitivity: Medium
This viewpoint represents the worst-case scenario view
from the north of the Water Gardens. Views into the
proposal suite are largely screened by existing landform,
vegetation and buildings. Mature trees (mainly Sycamores
and Poplars) along the river filter views. The civic centre is
visible through the trees in the far-distance. The existing
civic centre buildings are unattractive and do not contribute
positively to the public realm. The presence of the trees
and buildings makes this view shady and dark and not
particularly inviting. A narrow trodden path is located
between the boundary hedges of the residential
development to the west and the River.
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Receptor Reference
and Description
Viewpoint no. 12
Old Marlowes House
Grid reference:
E: 505534.537
N: 207308.917
Viewing altitude:
87.233m
See Figure 11.11
Viewpoint no. 13
Raised Pedestrian
walkway adjacent to
Hamilton House
Grid reference:
E: 505559.194
N: 207145.423
Viewing altitude:
95.414m
See Figure 11.12
Approx. Location in
Relation to the Site /
Reason for Choice /
Receptor Sensitivity
Description of the Existing View
Direction: SE
Approximate minimum
distance from site: 43m
Grade II* Listed Building.
Experienced by many
pedestrian and vehicular
receptors on Marlowes.
Sensitivity: High
Any external ground floor views are completely screened
towards the development by the existing flint wall. From
the pavement, the mid, left-hand side of the view includes
the civic buildings and associated parking and spaces and
the heavily treed residential western slopes of the town in
the distance. To the far-right hand side of the view, the
shopping parade on Marlowe’s east-side is visible, with the
newly renovated Georgian property in the foreground.
Oblique views are available towards the site from the
pavement and gateway of Old Marlowes House. From this
point, the site accommodates a large part of the view in the
middle distance. The north-eastern corner of the Civic
Centre building and town square are visible although much
of the remainder of the buildings are screened by mature
Limes on Marlowes. The town square is poorly contained
and lacks much in the way of visual or amenity features.
Dacorum Way is located to the north of the town square.
Marlowes Methodist Church (ridge height approximately
10.5m) and associated tree planting is identifiable. It hides
much of the college campus and provides a visual focus
half way along Marlowes. The three storey college building
in mid-southern area of the site is visible.
Mature
deciduous and evergreen trees (6 of which have TPOs)
mask many of the college buildings and provide a green
visual link to Gadebridge Park.
For pedestrians and drivers travelling north up Marlowes,
the site would be present to the mid-left of the view. At
times, pavement users would be immediately adjacent to
the proposal buildings and associated works.
Direction: SE
Approximate minimum
distance from site: 290m
Frequently used by
pedestrian receptors within
the area. Representative of
views from the New Town
shopping area.
Sensitivity: Medium
This view is largely dominated by Marlowes and the
buildings and spaces along it. In the foreground, a mixeduse mid-20th century development to the north of the
Market Square stands out.
The raised table to the south of the roundabout creates
threshold between the shopping area and the northern end
of Marlowes.
The mature trees south of Marlowes Methodist Church and
the church itself are noticeable features to the north and on
the right hand side of the view in the far distance. The
mature Limes adjacent to the Civic Centre town square are
visible.
The repeated shape of the lamp posts in this area creates a
sense of dated but functional coherence in this view.
Potential Effects
11.5.1
Document1
The potential effects are now described in relation to the scenarios for assessment described
in Section 11.3.13. The proposal presented is the result of a design process, which has
aimed to respond to the broad level guidance listed in the Hemel Hempstead Town Centre
Masterplan and planning policy, to the client’s brief and design team discussions. The
resultant scheme includes and integrates all primary level mitigation measures, which have
aimed to:
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11.5.2

Promote east-west pedestrian connections;

Create a new riverside walk along the River Gade;

Create a network of trees throughout the site;

Create a range of habitats;

Achieve a high quality of architecture;

Create more continuity of built form between Hemel Hempstead’s old and new towns;

Enhance the urban edge along Marlowes with a new feature atrium at its entrance;

Enhance the sense of a gateway setting at the Marlowes / Queensway junction; and

Create additional public spaces and improve the quality of the public realm.
The resultant scheme is described below according to the stages of the proposed
development’s life cycle presented in Section 11.3.13. These general potential effects
include the primary mitigation measures listed above and are considered in relation to each
townscape and visual receptor.
During Construction
11.5.3
The site will be altered almost in its entirety in accordance with the detail provided in
Chapter 3 of the ES.
11.5.4
The row of trees along the northern boundary of the site is to be retained, as part of the
landscape scheme for the site.
11.5.5
As such, this area will experience major change as old buildings are demolished, existing
trees removed, the river is re-aligned and the new facilities are built. As described in
Chapter 3 of the ES, this work will progress from north to south and is scheduled for
completion in 2014. The following additional factors are considered in the TVIA:
Document1

Site plant and equipment associated with the development could be a new but temporary
addition to the townscape;

Construction works could be lit up at various points in the year / day to extend working
hours on site;

Site-works could generate dust which could be visible at particular times;

The construction works will generate noise temporarily, with impacts on landscape
character; and

Public access in and around the site is likely to be managed by fencing areas off – at the
very least with hoarding.
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11.5.6
A CEMP will be implemented for the site that will include consideration of how visual impacts
of the development can be reduced, including screening and placement of construction
materials.
11.5.7
The duration of construction impacts change will be temporary.
The Site During Operation
11.5.8
Document1
At operation, the physical nature of the site will have almost entirely altered. The main points
are summarised below:

There will be fewer buildings with a larger footprint than currently exists making the site
contrast more with the characteristics of the surrounding areas.

Some site uses will change introducing a new foodstore and petrol filling station and
removing any civic uses.

Marlowes Methodist Church will be demolished along with all existing college buildings
and the borough Council offices that are part of Dacorum civic centre.

The proposed college and foodstore buildings will adopt a more contemporary aesthetic
and higher quality materials and detailing will be adopted through the scheme. The
rectilinear form of the corner of the proposed college building will be located closer to the
junction of Queensway and Marlowes than existing buildings, resulting in the removal of
two mature London Plane trees, which will be replaced.

The proposed foodstore and college buildings will create a more clearly identifiable
urban edge along Marlowes due to their increased proximity to the road (by approximate
10m).

The proposed outline education development located in the northwest of the site will be
located closer to the Leighton Buzzard Road / Queensway roundabout and will therefore
contribute more effectively to creation of a gateway experience at this point.

The proposed college building is around 10m higher than the existing college buildings
on the site. The height of the proposed foodstore is 9.5m at its lowest point and 12.5m
at its highest point (there is a larger atrium space near the entrance). No proposed
buildings will be higher than the existing civic buildings on the site.

Parking areas will be provided predominantly towards the south and west of the site.
Access to the college car park and main car parks of the foodstore will be over a new
vehicle access over the River Gade from Leighton Buzzard Road. Access to the decked
car park serving the foodstore and town centre will be from Marlowes (the new junction
for which is located further south of the existing Dacorum Way / Marlowes junction,
which is to be closed). The petrol filling station is accessed from Leighton Buzzard
Road. Parking associated with the outline planning application is proposed to be
accessed from Queensway.
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11.5.9

Pedestrian access and connectivity will be improved through the site through:

Realignment and strengthening of the River Gade riverside path which will be widened to
accommodate a cycle route.

The pedestrian route through the site will be maintained, during opening hours a level
change between Marlowes and the lower car park will be via the internal escalators in
the foodstore atrium, outside these times a staircase will be accessible. The path will be
through the lower car park to the new footbridge.

A new crossing point over the River Gade will provide a direct route from Marlowes to
Leighton Buzzard Road and the riverside path.

Provision for a future east-west connection to the south of the site, this should be
designed to deliver a high quality and distinctive public realm, with tree planting that
adds to Hemel Hempstead's sense of place.

The provision of an upgraded crossing point on Queensway.

New seating areas and improved public realm will be provided along Marlowes
integrating three areas that will read as spaces in their own right, which will be located:

At the junction of Marlowes / Queensway;

In-between the proposed college and foodstore buildings; and

At the foodstore entrance.

Artificial light spill from the proposed foodstore and petrol filling station will correspond
with opening times, which are likely to be extended in comparison to existing schedules.
The petrol filing station and foodstore car park lighting is expected to be switched off at
midnight.

New tree planting will replace and extend existing trees along Marlowes, Queensway,
The Leighton Buzzard Road and River Gade.
New wetland areas are proposed along The River Gade, which is to be re-aligned. The
land-form surrounding the River is to be re-graded to provide wetland habitats.
11.5.10 The duration of this change will be permanent.
The Site upon Establishment (15 years +)
11.5.11 In addition to the potential effects described above, upon establishment, the vegetation and
newly planted trees will have grown and matured. New habitats will have become
established and self-supporting.
11.5.12 The duration of this change will be permanent.
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11.5.13 The impact of the potential impacts of the proposals on the townscape and visual resource
are now reviewed.
Potential Townscape Effects
11.5.14 Table 11.18 provides a summary of the assessment on the townscape resource 45.
Table 11.18: Townscape Effects
Character Area
The Proposal Site
Sensitivity: LOW
Duration and
Type of Effect
Scenario
Description of Potential Effects
During
Construction
As described in Section 11.5.3.
The magnitude of change that this character area will
be subject to during the construction stage will change
the whole Proposal Site over a series of phases Temporary
(therefore the entirety of the site will not be affected at
once). Each change will be temporary in nature. The
location of the change is in central Hemel Hempstead Direct
and will be visible by most people who use the town.
Therefore, the magnitude of change and has been
assessed to be HIGH.
At Operation
The character area will change across a significant
proportion of its total area. The character area is
highly tolerant of change.
Change will have a
permanent effect on the area’s use, function, and feel.
However, at operation, the trees and planting areas
will have yet to become established. New public
realm treatments will improve the perceived quality of Permanent
this character area. Pedestrian connectivity and
access to habitats will be improved throughout. The
quality of car park lighting will be improved to meet Direct
current British Standards. Light spill from buildings is
likely to increase although the overall impact on the
character of this area will be minimal. More detail has
been provided in Section 11.5.8.
Therefore the magnitude of change has been
assessed to be HIGH.
By this time, proposed trees will have become more
established and the periphery of the site will appear
fairly well treed as a result. Despite the significant
loss of trees in the core of the site, and the unbroken Permanent
areas of car parking proposed, this change, in addition
When Established to the changes described at operation will have an
overall positive effect on the townscape. More detail Direct
is provided in Section 11.5.11.
The magnitude of change has been assessed to be
HIGH.
45
Impact
Assessment
(Prior to
Secondary
Mitigation)
Moderate
Adverse
Moderate
Beneficial in
relation to the
quality of built form
and movement
network
Adverse in relation
to the impact on
green
infrastructure
Moderate
Beneficial
Defiition: The combination of elements that contribute to landscape context, character and value.
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Character Area
The Gade Zone
Sensitivity: LOW
Duration and
Type of Effect
Scenario
Description of Potential Effects
During
Construction
The northern part of the character area will change
significantly as old buildings are demolished, existing
trees removed, the river is re-aligned and the new
facilities are built.
The southern part of the character area will be subject Temporary
to indirect change through the increased presence of
construction vehicles accessing the site, the potential Direct
viewing of site plant and exposure to noise, light and
dust.
Therefore, the magnitude of change has been
assessed to be HIGH.
At Operation
The nature of the change affecting this character area
is described in detail in Section 11.5.3. In addition:

The new buildings will create more of a
contrast between the north and south part of
the Gade Zone, which following completion
of the development may almost read as two
character zones;
Permanent

The reduced tree planting in the area will
initially reduce the perceived green
connection between this character area and Direct
Gadebridge Park however this will improve
over time; and

New public realm treatments will improve the
perceived quality of this character area.
Therefore the magnitude of change has been
assessed to be HIGH.
The established tree planting will improve the
perceived connection to Gadebridge Park, especially
to the west of the character area. The lack of trees in
the core of the site will be a noticeable loss in
comparison to the existing situation. The increased
space allocated to car parking is considered to have a
negative impact on townscape character. However, in Permanent
general, the quality of the built form and public realm
When Established of the development, especially around its periphery,
will be a beneficial improvement to the character of Direct
this area. The quality of car park lighting will be
improved to meet current British Standards. Light spill
from buildings is likely to increase although the overall
impact on the character of this area will be minimal.
The magnitude of change affecting this character area
has been assessed to be HIGH.
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Impact
Assessment
(Prior to
Secondary
Mitigation)
Moderate
Adverse
Moderate
Beneficial in
relation to the
quality of built form
Adverse in relation
to the impact on
green
infrastructure
Moderate
Beneficial
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Environmental Statement - Volume 1
Character Area
Hemel Old Town
Sensitivity: HIGH
Duration and
Type of Effect
Scenario
Description of Potential Effects
During
Construction
The physical fabric of this character area will not be
directly affected, however given that this character
area wraps around the north east corner of the site,
the experience of it, particularly around Queensway
and Marlowes, is highly likely to be temporarily Temporary
affected by light, noise, dust and traffic, which will
change the way it is perceived. In addition, views Indirect
towards the site will change to accommodate the
construction works.
Therefore the magnitude of change has been
assessed to be LOW.
At Operation
The character area will be affected indirectly by
changes in the views as described in the visual impact
study. Change is limited to a localised area in the
southern part of the character area around
Queensway and Marlowes. This area is particularly
important in terms of townscape functionality because
the southern part of this character area provides key
links between the old and new town. However, most
of the character area’s most sensitive assets are
located around High Street and will not be affected at
all by the proposed development.
The new college and foodstore buildings will be
constructed from higher quality materials and will be
more contemporary in style than the current buildings
in the Gade Zone visible from Hemel Old Town. The
quality of the built from will therefore be noticeably
higher.
The proposed location of the college building is closer
to the Queensway / Marlowes junction and the
Marlowes frontage which makes it a more dominant Permanent
feature in westerly views. Its recto-linear form could
better embrace the gateway node identified on the
northern end of Marlowes, although the impact of this Indirect
is softened by the proposed mature trees. Views
towards the proposed College from Hemel Old Town
now do not include the wooded backdrop of the town’s
western slopes.
The urban edge on Marlowes will change to be more
dominant and consistent. This change positively
affects the streetscape by providing a more
continuous urban edge to link the Old and New town
centres of Hemel Hempstead. However, there is a
lack of visual interest in the articulation of the
northeast corner of the foodstore.
East-west views through the site will be dominated by
parked cars although the proposals for new vegetation
and trees along Marlowes will partially screen and
filter views from lower elevations. New public realm
treatments will reflect positively upon the character
area.
Therefore the magnitude of change has been
assessed to be LOW.
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Impact
Assessment
(Prior to
Secondary
Mitigation)
Moderate
Adverse
Moderate
Beneficial
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Environmental Statement - Volume 1
The trees proposed along Marlowes and Queensway
should have become established and should serve to
soften built form:

At the junction of Queenway and Marlowes; Permanent
When Established

In-between the proposed college and
foodstore buildings; and
Indirect

To the south of the foodstore entrance.
Therefore the magnitude of change has been
assessed to be LOW.
Character Area
Moderate
Beneficial
Original Marlowes Zone
Sensitivity: MEDIUM
Scenario
Description of Potential Effects
Duration and
Type of Effect
During
Construction
The physical fabric of this character area will not be
affected during the construction of the development.
The northern part of the character area may be Temporary
subject to indirect change during the construction
period as views change to accommodate the
Indirect
construction work and traffic.
Therefore the magnitude of change that has been
assessed to be LOW.
At Operation
A proportion of the eastern edge of the character area
would be indirectly affected as northerly and northwesterly views change to accommodate the proposal.
The view from Old Marlowes House has been
assessed within the visual impact assessment (VP
12). The feature atrium would replace the Marlowes
Methodist church as a local landmark. Trees and
vegetation would not yet be established and therefore
the reduction of mature trees would be noticeable.
The proposed development would serve to improve
the connection between the old and new towns of
Hemel Hempstead and potentially improve footfall Permanent
along the street. This activity could have a positive
impact on businesses along Marlowes in the long Indirect
term. The improved built form will have a positive
impact on this character area.
The extended opening times of the foodstore and
associated carparking in comparison to existing uses
will mean that lighting levels are likely to increase in
some areas of the site. This will have an indirect
effect on the Original Marlowes zone. The effect
could have a positive impact on the perceived sense
of evening activity along Marlowes.
Therefore the magnitude of change that has been
assessed to be LOW.
Established trees planted along Marlowes will help
raise the perception of status along this street and link Permanent
this character area to Hemel Old Town / Gadebridge
When Established Park.
Therefore the magnitude of change that has been Indirect
assessed to be MEDIUM.
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Impact
Assessment
(Prior to Secondary
Mitigation)
Minor – Moderate
Adverse
Minor – Moderate
Beneficial
Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Character Area
Jellicoe Water Gardens
Sensitivity: MEDIUM
Scenario
Description of Change
Impact
Assessment
Duration and
Type of Impact (Prior to Secondary
Mitigation)
During
Construction
The physical fabric of this character area will not be
affected during the construction of the development.
The northern part of the character area may be
subject to slight indirect changes during the
construction period from one very specific viewpoint. Temporary
Any construction traffic will not be dissimilar to the bus
station traffic currently directed along Combe Road.
Indirect
The quality and flow of water downstream will be
maintained.
Therefore the magnitude of change that has been
assessed to be NEGLIGIBLE.
At Operation
The physical fabric of this character area will not be
affected by the proposed development. The view
from the bridge on Combe Street has been assessed
within the visual impact assessment (VP 11). This is
the only view from within the water gardens that could
be subject to any change.
The sense of continuity and integrity of green Permanent
infrastructure linking Gadebridge Park through the
Gade Zone and into the Jellicoe Gardens will be Indirect
improved due to proposals to extend the riverside
walk through the Gade Zone. This is likely to have a
positive impact on the use of the river corridor and the
Jellicoe Water Gardens.
Therefore the magnitude of change that has been
assessed to be LOW.
It is unlikely that the situation described above ‘at
operation’ will change when the scheme becomes Permanent
When Established more established.
Therefore the magnitude of change that has been Indirect
assessed to be LOW.
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Not Significant
Minor – Moderate
Beneficial
Minor – Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Character Area
The Western Slopes
Sensitivity: MEDIUM
Scenario
Description of Change
Impact
Assessment
Duration and
Type of Impact (Prior to Secondary
Mitigation)
During
Construction
The physical fabric of this character area will not be
affected during the construction of the development.
The north eastern edge of the character area will be
most affected by the construction of the development
and in particular, the properties with a front elevation
directly overlooking the site. The views from these Temporary
properties are assessed in the visual impact
assessment.
Indirect
Views and potentially some traffic disruption may
affect users of the Leighton Buzzard Road although
the nature of the change will be temporary.
Therefore the magnitude of change that has been
assessed to be LOW.
At Operation
Document1
The eastern edge of the character area will be subject
to indirect change as views alter to include a new
vehicular entrance to the site.
The removal of dated and unsightly buildings on the
western edge of the Gade Zone will have a positive
impact on this character area as will the more explicit
expression of the River Gade and the high quality
architectural treatment of proposed buildings. The
proposed entrance to the foodstore on Leighton
Buzzard Road could raise the perceived status of this
part of town. The increased tree planting along the
eastern side of the street will help reinforce this.
The removal of existing mature trees on the site will
have an overall negative effect on views from this
character area as will the increased and extended
areas of car parks. The eastern edge of the foodstore
service yard, building and decked car park will be
visible. Proposed vegetation may screen some parts
of these façades although the visual impact of this will
not be apparent until vegetation has become Permanent
established.
The extended opening times of the foodstore and Indirect
associated car parking in comparison to existing uses
will mean that lighting levels are likely to increase.
This will have an indirect effect on the Western
Slopes. The effect could be perceptible from some
nearby residential properties on the western slopes;
however proposed planting could filter this effect over
time. The increased lighting could have a positive
effect on the perceived sense of safety after dark
along Leighton Buzzard Road.
The proposed development of additional college
facilities in the north west of the site will impact views
to the north-east of the character area (see the visual
impact assessment for more detail).
Much of the remainder of the character area will be
unaffected by the changes proposed.
Therefore the magnitude of change has been
assessed to be LOW.
233
Minor – Moderate
Adverse
Minor – Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
The nature of the adjacent development to this
character is likely to be perceived to be of higher
quality architecture than the existing situation, but with
a much weaker network of mature trees.
The
character area's proximity to a strengthened River
Gade corridor, together with increased tree planting
along the Leighton Buzzard Road may mitigate the Permanent
When Established loss of trees somewhat especially given that direct
views into the site are limited from the Western Indirect
slopes. The established wetland and Riverside Walk
will also serve to mitigate the loss of trees within the
site. Additional light spill perceived could be partially
filtered by vegetation at establishment.
Therefore the magnitude of change has been
assessed to be LOW.
Minor – Moderate
Beneficial
Potential Visual Effects
11.5.15 An overall significance for impact has been assessed by combining sensitivity as assessed
in the baseline, with magnitude of change as explained in Section 11.3.56 Impact
assessments in Table 11.19 relate to the descriptions provided in Section 11.3.57.
Table 11.19: Visual Effects
Viewpoint 1
St Marys Church
Scenario
Description of Change
During
Construction
Tall cranes could be perceptible but not particularly
noticeable if used on the eastern edge of the site.
The view would change temporarily in the far distance Temporary
and changes would be slightly more obvious in winter
months when trees are not in leaf although would be
Indirect
screened by existing site features.
Therefore the magnitude of change that has been
assessed to be NEGLIGIBLE.
Not Significant
At Operation
There is a slight possibility that the very upper part of
the foodstore development would be visible in the far
distance, opposite Maitland House, in winter, when Permanent
trees are not in leaf. This change in the view would
barely be perceptible because it would constitute such
Indirect
a small proportion of the view.
Therefore the magnitude of change that has been
assessed to be NEGLIGIBLE.
Not Significant
Established vegetation would not be visible from this
viewpoint and therefore the assessment is the same Permanent
When Established as ‘at operation’.
Therefore the magnitude of change that has been Indirect
assessed to be NEGLIGIBLE.
Not Significant
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Sensitivity: VERY HIGH
Duration and
Type of Impact
234
Impact Assessment
(Prior to Secondary
Mitigation)
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Viewpoint 2
Old Lloyds Bank (ALH House)
Scenario
Description of Change
During
Construction
The north-eastern corner of the site would be highly
visible from this viewpoint in the centre of the view.
Key stages of the construction process that would
change the view from this receptor include:

Site fencing;

The removal of the existing Plane Trees on
Marlowes / Queensway;

The demolition of the existing college Temporary
buildings; and

The construction of the new college building. Indirect
In addition, site plant, vehicles and associated
scaffolding and infrastructure would be visible. The
buildings along Queensway to the left and right hand
side of the foreground would detract a little from the
construction activity.
Therefore the magnitude of change that has been
assessed to be MEDIUM.
At Operation
The view would permanently change to include the
new college building, the northeast corner of which
would approximately 10m closer to the Marlowes /
Queensway junction than the current building. This
move raises the ground floor level of the college
building by 1m. The new college building will be
approximately 9m higher than the existing college
building at Queensway / Marlowes. This means that it
will become a new, more dominant built form in this
view. Its dominance will create the impression of a
higher density node at Marlowes and Queensway and
will block views to the Western Slopes and wooded
horizon to the west, therefore removing the visual
connection between the old town and the surrounding
landscape.
The dominance of the proposed building will mean
that it will play a role in the perception of townscape
character from this receptor. The proposed rectilinear
form of the building and the minimalistic approach to Permanent
its roof conflicts with the characteristics of the old town
where many of the corner buildings have more Indirect
articulated corner features such as curved building
lines or windows and there is a varied but commonly
well-articulated roofscape.
The sharp rectilinear
corner of the proposed building conflicts with these
spatial characteristics and therefore does not
contribute to this gateway node in the most positive
way. However, the quality and condition of the
architecture will be an improvement on the existing
situation and the concentration of activity at this
location will reinforce the sense of arrival / gateway.
The building's impact is softened by the two proposed
trees adjacent to its entrance, which mitigate for the
loss of the existing plane trees here. However their
impact will not be appreciated until they mature. The
proposed materials are generally complimentary in
tone and in keeping with the character of the old town.
Therefore the magnitude of change that has been
assessed to be MEDIUM.
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Sensitivity: MEDIUM
Duration and
Type of Impact
235
Impact Assessment
(Prior to Secondary
Mitigation)
Moderate
Adverse
Moderate
Adverse
The Link, Hemel Hempstead
Environmental Statement - Volume 1
The general quality of the new buildings will be higher
than the existing buildings are now and would be in
the future, which is likely to have a positive impact on
the overall perceived quality of this part of the old
town, which generally improves along High Street.
However, the proposed college's dominance and Permanent
incongruous form will still jar with the character of the
When Established Old Town having an adverse impact on this receptor.
However, the proposed trees outside the new college Indirect
building will have matured to soften the view from this
receptor, which lowers the magnitude of change
experienced from the viewpoint.
Therefore the magnitude of change that has been
assessed to be LOW.
Viewpoint 3
The Bury; Main entrance. Central South Façade.
Scenario
Description of Change
During
Construction
Activity and change particularly, on the northern edge
of the development would be partially visible beneath
the tree canopies towards the beginning of the
construction phase. Much of the site plant and Temporary
vehicles and activity would be largely screened by
existing trees. The use of tall cranes and scaffolds is Indirect
likely to be visible over the tops of the Yew trees.
Therefore the magnitude of change that has been
assessed to be LOW.
At Operation
The view from the centre of The Bury would continue
to include the existing avenue of Yew trees in the
foreground.
This would be the case for the
foreseeable future.
The existing and new college buildings are set back
from Queensway to a similar extent. The new college
building is approximately 9m taller than the existing
building.
This means that this view would
permanently change to include the new college
building, which would be just visible above the tops of
the Yew trees. This would create a new urban edge
along Queensway, which would respond positively to
the townscape characteristics here.
Permanent
This portion of the building is finished in render and
has a number of windows along it. The render will
encourage the building to recede visually.
The Indirect
arrangement of the buildings creates visual interest in
the view.
The materials are considered to be
complementary to the character of The Bury. The
quality of the buildings and their finishes would be an
improvement in comparison to the existing palette
used. As such, the overall impact to this particular
view has been assessed as positive.
It should also be noted that views towards the northeastern corner of the site would be experienced by
pedestrian receptors leaving The Bury.
The magnitude of change that has been assessed to
be LOW.
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Beneficial in relation
to the perceived
condition of the built
form from this
receptor.
Adverse in relation to
the perceived
architectural
response to
townscape setting
and character.
Sensitivity: HIGH
Duration and
Type of Impact
236
Minor – Moderate
Impact Assessment
(Prior to Secondary
Mitigation)
Moderate
Adverse
Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
The view described above would not change Permanent
significantly at establishment.
When Established
Therefore, the magnitude of change is considered to
Indirect
be LOW.
Viewpoint 4
Gadebridge Park, Eastern Entrance
Scenario
Description of Change
During
Construction
The north-eastern corner and eastern edge of the site
would be highly visible from this viewpoint. Key
stages of the construction process that would change
the view from this receptor include the:

Site fencing;

Removal of 2 of the existing Plane Trees on
Marlowes / Queensway.
All remaining
existing deciduous trees are to be retained
within the conservation area on Queensway); Temporary

Removal of the existing mature trees on
Marlowes and within the college campus;
Indirect

Demolition of the existing college buildings;

Demolition of the Marlowes Methodist
Church; and

Construction of the new college building and
foodstore.
In addition, site plant, vehicles, activity and associated
scaffolding and infrastructure would be visible.
Therefore the magnitude of change that has been
assessed to be MEDIUM.
At Operation
A proportion of this view would permanently change to
include the proposed college building and foodstore
with the effect of:

A more dominant and consistent building line
and form to the north-east of Marlowes that
balances out and detracts from Maitland
House and creates a stronger urban form
adjacent to the road;

A replacement visual feature along Marlowes
(in the form of the foodstore atrium) opposite
Maitland House (which would be lit up during
foodstore opening times);

More contemporary and higher quality
Permanent
architecture

Reduced grass verge areas on the right- Indirect
hand side of the view;

A reduced number of mature trees along
Marlowes, which will be replaced by trees not
smaller than 4.5m in height;

A reduced number of mature trees to the
right-hand side of the view, which will be
replaced with wetland planting; and

More dominant buildings at the junction of
Marlowes and Queensway creating a
stronger urban edge.
The tone of proposed materials for the new college
building compliments the materials in the Old Town.
Therefore the magnitude of change is considered to
be MEDIUM.
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Beneficial
Sensitivity: MEDIUM
Duration and
Type of Impact
237
Moderate
Impact Assessment
(Prior to Secondary
Mitigation)
Moderate
Adverse
Moderate
Beneficial in relation
to the components of
the view relating to
built form.
Adverse in relation to
the impact on the
components of the
view relating to
green infrastructure.
The Link, Hemel Hempstead
Environmental Statement - Volume 1
As time progresses, the trees planted along Marlowes
would mature to become more dominant features in
the view described above. However, the planting
associated with the River Gade would only be semimature and not large enough to break the horizon in
the same way that existing vegetation does
(especially given the higher elevation of the building). Permanent
As such, it would not have a significant impact on this
When Established view at establishment. Despite this loss, receptors
experience this view on the move and at close Indirect
proximity.
Therefore, the overall impression of
change at this particular point is likely to be generally
positive for the reasons described above (at
operation).
Therefore the magnitude of change on is considered
to be MEDIUM.
Moderate
Beneficial
Viewpoint 5
Gadebridge Park, Western Entrance
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
The north-western corner of the site would be clearly
visible in the middle distance. Key stages of the
construction process that would change the view from
this receptor include the:

Site fencing;

Removal of mature deciduous trees along
Temporary
The River Gade; and

Demolition of existing college buildings.
In addition, site plant, vehicles, activity and associated Indirect
scaffolding and infrastructure would be visible.
Construction works would be phased, the proposed
college building to the northwest of the site being last
to be completed.
Therefore the magnitude of change is considered to
be MEDIUM.
At Operation
The proposed building on the north west of the site is
not at detailed stage yet and therefore these
comments are based on outline information only.
Users exiting Gadebridge Park at this point would
experience the following changes in the view upon
completion of the full development:

The entrance would reveal views across the
college’s northwest development to include
the building, proposed car park, boundary
hedges, and replacement deciduous trees.
The proposed hedge is likely to improve the
overall look and feel of the existing Western Permanent
Red Cedar boundary hedge, which is
domineering and incongruous with its river Indirect
valley setting.
However, the proposed
planting will take time to become established.
Existing car parking is not as well screened
and is located to the right-hand side of the
view;

Unsightly college buildings would be
removed and replaced with a new building;

Built form would be located to the right hand
side of the view. The view from this entrance
would be mainly of the side of the building.
There is potential for the built form to
respond better to this important gateway
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Minor – Moderate
Adverse
Minor – Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
node that marks the northwestern entrance
in Hemel Hempstead; and

There would be a significant reduction in the
number of mature trees present in the view
flanking the River Gade, which would have a
negative impact.
In general, the location and design of this part of the
college campus should be carefully considered to
maximise townscape value and contribute positively to
the River Gade corridor. However, the broad level
changes to the site have been assessed as a general
improvement to the existing situation.
Therefore the magnitude of change is considered to
be MEDIUM.
Based on the broad level of information available for
the outline application, upon establishment, and in
addition to the description provided above, the
proposed boundary vegetation will have matured to Permanent
When Established better screen and filter views into the car park and
beyond towards the foodstore service yard and car Indirect
parks.
Therefore the magnitude of change is considered to
be MEDIUM.
Minor – Moderate
Beneficial
Viewpoint 6
Century House
Sensitivity: MEDIUM
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
The north-western corner of the site would be visible
from this viewpoint. A large proportion of views would
include:

Site fencing;

Removal of the existing Western Red Cedars
and mature deciduous trees;

Demolition of existing college;
Temporary

The construction of the foodstore, college
building, petrol filling station and engineering
works associated with the River Gade Indirect
proposals; and

The construction of the building in the north
west of the site as proposed in outline and its
associated car park.
Therefore the magnitude of change is considered to
be MEDIUM.
At Operation
The proposals would change this view as follows:
Prior to the completion of the north-western college
building:

The removal of dated and dilapidated
buildings is considered to have a positive
overall impact on receptors from this
viewpoint. The replacement new buildings
Permanent
could be considered to have a positive effect,
depending on the detail design. In general
terms, the placement and design of the Indirect
building could far better contribute to this
gateway into town.

The removal of the Western Red Cedars and
the replacement deciduous avenue is
considered to be an improvement to
townscape
character
however
until
replacement trees mature, their loss is
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Moderate
Adverse
Prior to the
completion of the
northwest college
building the impact is
considered to be
Minor – Moderate.
Beneficial
Upon completion of
the northwest
college building the
impact is considered
to be
Moderate.
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Beneficial
considered a detrimental to a small
proportion of this view.

A proportion of the view will accommodate
more open and direct views of more modern
buildings, which will be located at an
increased distance from the receptor. The
foodstore façade will be a noticeable feature
in the view. The north and western façades
lack visual interest and the lighter materials
contrast more strongly with the background,
making it visually more prominent. There will
be an increased perception of artificial
lighting from car parking, the petrol filling
station and foodstore.
There will be
significantly fewer mature trees in the
northern part of the site. This will create the
impression of a weakened sense of green
infrastructure in the short term (until the
north-western college building blocks views).
Prior to the completion of the northwest college
building, the magnitude of change is considered to be
LOW.
Upon completion of the north-western college
building:

Views will be almost completely blocked
towards the foodstore and remaining
development site by the new building. The
matured vegetation will filter views. The
eastern slopes of Hemel Hempstead will still
be visible above its rooftop.
Upon completion of the northwest college building, the
magnitude of change is considered to be MEDIUM.
Over time, the trees proposed for the college car park
and along the River Gade are likely to create much
more visual interest in the foreground, which will block
views towards the foodstore car park. Western facing Permanent
When Established building façades are likely to be visible over the top of
tree canopies and car parking, and possibly the Indirect
proposed college building in the northwest of the site.
Therefore the magnitude of change is considered to
be MEDIUM.
Moderate
Beneficial
Viewpoint 7
Warners End Road. From the Southeast Corner of
Gadebridge Court
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
Key stages of the construction process that would
change the view from this receptor include the:

Site fencing;

Demolition of existing college buildings;

Removal of existing deciduous trees;

Works to re-landscape the River Gade; and

The construction of the new foodstore, Temporary
college, engineering works associated with
the River Gade proposals and the college Indirect
buildings proposed in outline in the north
west of the site and surface car parks
In addition, site plant, vehicles, activity and associated
scaffolding and infrastructure would be particularly
visible from this elevated position, which allows for
more expansive views into the site. The urban nature
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Minor – Moderate
Adverse
The Link, Hemel Hempstead
Environmental Statement - Volume 1
of this view makes it less sensitive to the activity
associated with construction sites.
Therefore the magnitude of change is considered to
be MEDIUM.
At Operation
The proposals would permanently change a
proportion of this view as follows:
Prior to the completion of the north-western college
building:

Dated and unsightly college buildings would
be removed, which would benefit this view;

All new built form would provide a similar
hierarchy of built form in the view to the
existing situation. However, the proposed
foodstore building would be higher and
bulkier than the existing building.
New
buildings would achieve a higher quality and
more contemporary aesthetic. The foodstore
façade will be a noticeable feature in the
view. The north and western façades lack
visual interest and the lighter materials
contrast more strongly with the background,
making it visually more prominent;

There would be less tree planting and green
space visible throughout the site, which
would be a noticeable adverse change,
especially while new planting is becoming
established;
Permanent

The eastern slopes of the town would still be
visible from this viewpoint;

More car parking will be visible in the middle Indirect
distance. Slightly less car parking will be
visible in the short distance; and

There will be an increased perception of
artificial lighting from car parking, the petrol
filling station and foodstore.
Prior to the completion of the northwest college
building, the magnitude of change is considered to be
LOW.
Upon completion of the north-western college
building:

To the northwest of the site, existing built
form would be replaced by the college
building proposed in outline. The proposed
building in the northwest of the site will be
significantly higher than the existing building;
and

The proposed building would block all views
to the foodstore, its car parks and service
yards and has the potential to contribute
positively to this gateway into town.
Upon completion of the northwest college building, the
magnitude of change is considered to be MEDIUM.
Tree planting adjacent to the Queensway / Leighton
Buzzard Road will have matured to soften this edge Permanent
and create a more appropriate sense of arrival into the
When Established town centre.
Therefore the magnitude of change is considered to Indirect
be MEDIUM.
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Prior to the
completion of the
northwest college
building the impact is
considered to be
Minor
Adverse
Upon completion of
the northwest
college building the
impact is considered
to be
Minor – Moderate
Beneficial
Minor – Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Viewpoint 8
78 BURY ROAD
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
Key stages of the construction process that would
change the view from this receptor include the:

Site fencing;

Demolition of existing college buildings;

Removal of existing deciduous trees along
the River Gade;

The construction of the college building,
petrol filling station and engineering works
associated with the River Gade proposals;
Temporary
and

The construction of the college buildings
proposed in outline in the north west of the Indirect
site and surface car parks.
In addition, site plant, vehicles, activity and associated
scaffolding and infrastructure would be visible.
Changes in the view will be perceived in context of a
busy, urban environment. Existing trees will block
many of the views towards the site.
Therefore the magnitude of change is considered to
be LOW.
At Operation
The proposals would permanently change a
proportion of this view as follows:

Existing, unsightly college buildings would be
removed;

The college buildings proposed in outline in
the north west of the site would be visible
through the trees to the north of the Leighton
Buzzard Road.
This building will be
substantially higher than the existing college Permanent
building located here although would look
more contemporary in its design. Views
would be partially filtered by proposed tree Indirect
planting on Leighton Buzzard Road, the
extent to which will change over time;

A reduced amount of car parking would be
visible; and

Existing trees are likely to filter many of the
views towards the site.
Therefore the magnitude of change is considered to
be LOW.
In addition to the view described above, over time, the
trees proposed along the Leighton Buzzard Road are Permanent
likely to create more visual interest in the mid-ground
When Established of the view.
Therefore the magnitude of change is considered to Indirect
be LOW.
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Minor
Adverse
Minor
Beneficial
Minor
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Viewpoint 9
Leighton Buzzard Road / Riverside Walk
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
Key stages of the construction process that would
change the view from this receptor include the:

Site fencing;

Demolition of existing college and civic
buildings;

Removal of existing deciduous trees along
the River Gade; and

The construction of the new foodstore, Temporary
college, filling station engineering works
associated with the River Gade proposals Indirect
and the college buildings proposed in outline
in the north west of the site and surface car
parks.
Change would only be perceptible to the right-hand
side of the view when travelling north.
Therefore the magnitude of change is considered to
be MEDIUM.
At Operation
The proposals would permanently change this view
as follows:

The proposed petrol filling station and car
wash would be intrusive on the right hand
side of the view. This would create more
movement and artificial light in the view,
which would attract more attention to it.
However, proposed tree and habitat planting
around the River Gade will mitigate this
impact somewhat by partially filtering views
(the extent to which will change over time).
The removal of the intrusive red-brick DBC
building would be an improvement in the
view;

The re-routed River Gade and riverside walk
would promote the presence of the river and Permanent
make it a more noticeable feature within the
view. The demolition of college buildings to
the north will provide a more obvious visual Indirect
connection between the receptor and
Gadebridge Park / The Bury – depending on
the detailed resolution of the proposed
building to NW site; and

Increased car parking to the right-hand side
of the view will be particularly noticeable due
to its extended footprint which will add
movement, more reflective elements, and
more artificial light into the view. In addition,
the service yard and the back of the
foodstore will be visible from this point,
especially in the short-term. This is the least
visually interesting elevation of the foodstore.
Therefore the magnitude of change is considered to
be MEDIUM.
The established planting along the River Gade will
create more visual interest in the foreground and to Permanent
the right-hand side of this view. This will screen some
When Established views to the car park and petrol filling station.
Therefore the magnitude of change is considered to Indirect
be MEDIUM.
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Minor – Moderate
Adverse
Minor – Moderate
Beneficial
Minor – Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Viewpoint 10
100 Bury Road
Sensitivity: HIGH
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
Key stages of the construction process that would
change a good portion of the view from this nearby
receptor include:

Site fencing;

Demolition of the existing college buildings;
and

Construction of the foodstore and associated Temporary
parking, college, petrol filling station, car park
and road infrastructure and engineering
Indirect
works along the River Gade.
In addition, site machinery and vehicles could be
visible above the fencing due to the elevated position
of this receptor, however these changes would be
perceived in context of a busy urban environment.
Therefore the magnitude of change is considered to
be MEDIUM.
At Operation
This open, elevated view across the site would
change to include the vehicular entrance to the
foodstore, which would be in close proximity to this
receptor and would create additional traffic and
movement in this view, for longer periods of time.
A surface car park would still accommodate a portion
of the view but behind this, the foodstore's service
yard, western elevation of the car park and main
foodstore building would be visible in place of existing
college buildings. The existing, unsightly, dilapidated
college buildings will have been removed from the
view and new planting is proposed which will become
established over time. The dominance of built form in
this view will generally be reduced resulting in an
increased sense of openness to the right-hand side of
the view, but less so to the left.
This view is likely to change to include more artificial Permanent
light associated with the foodstore, car park and petrol
filling station for longer periods of time. This is likely to
Indirect
have on overall adverse effect on this receptor.
There would be a noticeably lower proportion of green
space and mature trees in the proposed view from this
receptor. However the proposed wetlands flanking
the River Gade will create an increased sense of
diversity in the foreground of the view. New trees
proposed throughout the site will partially mitigate the
loss of existing mature trees although they will take
some time to mature.
Overall, the effect of the new buildings is considered
to have a beneficial impact. The combined effect of
the loss of existing and vegetation and the lack of
establishment of proposed vegetation is considered to
be an adverse impact at this stage in the project's life
cycle.
Therefore the magnitude of change is considered to
be MEDIUM.
Established planting proposed along the River Gade, Permanent
When Established in the riverside park and along the service yard
boundary will have established to better screen and
filter some potential views towards the car park areas, Indirect
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Moderate – Major
Adverse
Moderate – Major
Beneifical in relation
to the components of
the view relating to
built form.
Adverse in relation to
the impact on the
components of the
view relating to
green infrastructure
and the perception of
artificial light after
dark.
Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
vehicular entrance and western elevation of the
foodstore. The vegetation will also provide increased
visual interest in the foreground and will mitigate for
some of the adverse impacts of this development on
this receptor, which improves the situation described
above. Artificial light may still be very perceptible
although could be partially filtered by established
trees. The increased size of the trees of this point in
the project's lifecycle better mitigates for the loss of
existing trees and therefore reduces the magnitude of
change.
Therefore the magnitude of change is considered to
be LOW.
Viewpoint 11
Water Gardens North
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
Very little of the construction phase would be visible
from this viewpoint. There may be a possibility the
Dacorum Way would be used for access.
Therefore the magnitude of change is considered to
be NEGLIGIBLE.
At Operation
This view would barely change during operation. It
would be very much dominated by the existing
Sycamore trees to the south of the site and existing
civic buildings.
Therefore the magnitude of change is considered to
be NEGLIGIBLE.
This view would barely change during operation.
Established vegetation would not have an impact on
When Established this receptor.
Therefore the magnitude of change is considered to
be NEGLIGIBLE.
Temporary
Not Significant
Indirect
Permanent
Not Significant
Indirect
Permanent
Not Significant
Indirect
Viewpoint 12
Old Marlowes House
Sensitivity: HIGH
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
The south-eastern corner of the site would be highly
visible from this viewpoint.
Key stages of the
construction process that would change the view from
this nearby receptor include the:

Site fencing;

Removal of the existing mature trees
throughout the site including the mature
cypress and Western Red Cedar TPOs;

Demolition of existing college buildings, civic
centre and the Marlowes Methodist church;
and
Temporary

Construction of the college and foodstore
and
associated
car
parking
and Indirect
infrastructure.
In addition, site plant, vehicles, activity and associated
and infrastructure would be visible over the hoarding.
The changes in the view form a large part of it but
would be perceived in context of a busy urban
environment. Changes would be experienced at an
oblique angle from this receptor but more directly by
people using the adjacent pavement.
Therefore the magnitude of change is considered to
be MEDIUM.
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Moderate – Major
Adverse
The Link, Hemel Hempstead
Environmental Statement - Volume 1
At Operation
The proposals would permanently change this view
as follows:

The new car park on the decked level would
be visible in the foreground;

The proposed foodstore and college would
replace the existing buildings present on the
eastern edge of the proposal side, located
10m closer to the pavement, protruding to a
similar extent as the Marlowes Methodist
Church (which would be removed). These
would create a more defined urban edge
along Marlowes;

The location of the foodstore, with its feature
atrium would replace the focus point between
the old and new towns, currently created by
the Marlowes Methodist Church.
The
presence of the atrium and the associated
entrance square would be a positive addition
to the street-scape in views from this Permanent
direction;

The civic square would be replaced by a car Indirect
park;

Views of the proposed car park from this
receptor would be partially screened by new
planting and streetscape interventions on
Marlowes. This serves to mitigate for the
loss of the existing civic square which
although is very large, is poorly enclosed, is
of a poor quality and lacks visual features.
The avenue of trees would create a more
formal visual impression of this part of
Marlowes. The planting would take some
time to become established; and

Tree planting along the southern pedestrian
east-west link has the potential to filter views
to the car park although insufficient detail is
available to enable further comment.
Therefore the magnitude of change is considered to
be MEDIUM.
Over time, the proposed trees would replace the effect
of the lost trees adjacent to Marlowes, including the 6
TPO trees located to the north of Dacorum Way. This Permanent
would soften views and create a broken avenue along
When Established Marlowes, which could be perceived to link to the
Indirect
trees present in Gadebridge Park.
Therefore the magnitude of change is considered to
be MEDIUM.
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Moderate
Beneficial
Moderate
Beneficial
The Link, Hemel Hempstead
Environmental Statement - Volume 1
Viewpoint 13
Hamilton House, Raised Pedestrian Walkway
Sensitivity: LOW
Scenario
Description of Change
Duration and
Impact Assessment
Type of Impact
During
Construction
The south-eastern corner of the site would be visible
from this viewpoint. Key stages of the construction
process that would change a minor portion of the view
in the mid-far distance include the:

Site fencing;

Removal of the existing mature trees
throughout the site;

Demolition of the Marlowes Methodist
Temporary
church; and

Construction of the foodstore and associated
Indirect
car parking.
In addition, site plant, vehicles, activity and associated
and infrastructure would be visible over the fencing.
The construction work would form a minor part of the
view and would be perceived in context of a busy
urban area.
Therefore the magnitude of change is considered to
be LOW.
At Operation
The proposals would permanently change a small
proportion of this view in the mid to far distance as
follows:

There will be fewer trees located within the
view at this point which would have an
adverse impact on a proportion of this view.
One impact would be that there would be
less of a sense of enclosure in the southeastern corner of the site; and
Permanent

The Marlowes Methodist Church would be
demolished and replaced by the foodstore.
More of the frontage of the foodstore would Indirect
be visible due to the removal of trees
however in the long term; the proposed trees
would serve to replace this stock.
The proposed foodstore would introduce a new hub of
activity half way between the old and the new town
with a more modern architectural finish to buildings.
Therefore the magnitude of change is considered to
be LOW.
Over time, the proposed trees would replace the lost
trees on and adjacent to Marlowes. This would soften
views and create a broken avenue along Marlowes, Permanent
When Established which could be perceived to link to the trees present in
Gadebridge Park.
Indirect
Therefore the magnitude of change is considered to
be LOW.
Minor
Adverse
Minor
Beneficial
Minor
Beneficial
Mitigation and Enhancement Measures
11.6.1
Document1
The following additional mitigation measures have been agreed to enhance the potential
effects of the scheme.
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Environmental Statement - Volume 1
Design and Specification Measures
11.6.2
The design of the northwest college site will be designed to respond positively to its
townscape context. It will create a strong urban edge along Marlowes and Queensway. The
development will be a high quality and sensitive design response that will aim to raise the
status of this northwestern gateway into town and enhance the River Gade corridor.
11.6.3
The pedestrian link to the south of the site will become a strong and legible east-west link
with tree planting along its length. The design will aim to deliver a high quality and distinctive
public realm that adds to Hemel Hempstead's sense of place.
11.6.4
To minimise light spill from external lighting, the following general principles taken from the
Institute of Lighting Engineers, Guidance Notes for the Reduction of Obtrusive Light (2011)
will be delivered:

Lighting is directed downwards wherever possible to illuminate its target. If there is no
alternative to up-lighting, then the use of shields and baffles will help reduce spill light to
a minimum;

Lighting is designed to minimise the spread of light near to, or above the horizontal;

Lighting will be designed to the correct standard for the task and not over light;

The main beam angle of all lights proposed directed towards any potential observer is
kept below 70 degrees. It should be noted that the higher the mounting height, the lower
the main beam angle could be. This will help reduce the effect of glare and light spill on
neighbouring dwellings, passing motorists, pedestrians, etc;

Lighting will be directed to minimise and preferably avoid light spillage onto neighbouring
properties;

Wherever possible use floodlights with asymmetric beams that permit the front glazing to
be kept at or near parallel to the surface being lit; and

The lights used will be the most efficient taking into account cost, energy use, colour
rendering and the purpose of the lighting scheme required. All lighting schemes should
meet British Standards.
At Operation and Establishment
11.6.5
Document1
A Landscape Management and Maintenance Plan has been agreed to be prepared ensure
new vegetation and public realm interventions are appropriately cared for. Vegetation and
trees are to be managed and replaced, as agreed, as necessary in order to retain and
improve the character of the scheme.
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Environmental Statement - Volume 1
Residual Effects
11.7.1
The residual effects of the development consider the impact of any additional mitigation
measures on the proposal's initial impact on the townscape and visual resource.
Residual Effects on the Townscape Resource
11.7.2
Table 11.20 summarises the effect of mitigation measures on the townscape resource.
Table 11.20: Residual Impacts on Townscape Resource
Receptor: The Proposal Site
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Very high
Moderate
Adverse
No change
Very high
Moderate
Adverse
High
Moderate
Beneficial in
relation to the
quality of built
form and
movement
network
Moderate
Adverse in
relation to the
impact on green
infrastructure
Limiting light spill from the
development will have a small
impact on limiting the overall
perceived change of character
after dark, however this is
unlikely to affect the overall
magnitude of change of
effects on this character area.
The delivery of high quality,
well-treed east west link may
mitigate for the loss of trees
within the site itself.
High
Moderate
Beneficial
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
High
Moderate
Beneficial
At Operation
Established
High
Receptor: The Gade Zone
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
High
Moderate
Adverse
No change
Very High
Moderate
Adverse
High
Limiting light spill from the
development will have a small
impact on limiting the overall
Moderate
perceived change of character
Beneficial in
after dark, however this is
relation to the
unlikely to affect the overall
quality of built
magnitude of change of
form
effects on this character area.
Moderate adverse The delivery of a new high
in relation to the
quality college building to the
impact on green
northwest of the site will
infrastructure
enhance the perception of this
character
area
from
surrounding areas in the town.
The delivery of a high quality,
High
Moderate
Beneficial
At Operation
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Environmental Statement - Volume 1
well-treed east west link may
mitigate for the loss of trees
within the site itself.
Established
High
Moderate
Beneficial
Receptor: Hemel Old Town
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
High
Moderate
Beneficial
Sensitivity: HIGH
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Moderate
Adverse
No change
Low
Moderate
Adverse
At operation
Low
Moderate
Beneficial
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Low
Moderate
Beneficial
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Moderate
Beneficial
Established
Low
Receptor: Original Marlowes Zone
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Minor / Moderate
Adverse
No change
Low
Minor /
Moderate
Adverse
Minor / Moderate
Beneficial
Limiting light spill from the
development will have a small
impact on limiting the overall
perceived change of character
after dark, however this is
unlikely to affect the overall
magnitude of change of
effects on this character area.
The delivery of high quality,
well-treed east west link may
mitigate for the loss of trees
within the site itself and will
help to provide a stronger
southern
edge
to
the
proposed car park. However,
this is unlikely to affect the
overall magnitude of change
of effects on this character
area.
Low
Minor /
Moderate
Beneficial
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Moderate
Beneficial
At operation
Established
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Low
Medium
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Receptor: Jellicoe Water Gardens
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Negligible
Not Significant
No change
Negligible
Not Significant
At operation
Low
Minor / Moderate
Beneficial
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Low
Minor /
Moderate
Beneficial
Established
Low
Minor / Moderate
Beneficial
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Low
Minor /
Moderate
Beneficial
Receptor: The Western Slopes
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Minor / Moderate
Adverse
No change
Negligible
Minor /
Moderate
Adverse
Minor / Moderate
Beneficial
Limiting light spill from the
development will have an
impact on limiting the overall
perceived change of character
after dark, especially from the
eastern edges of the character
area. However this is unlikely
to affect the overall magnitude
of change of effects on this
character area.
The delivery of a new high
quality college building to the
northwest of the site will
enhance the perception of this
character
area
from
surrounding areas in the town
but will be unlikely to change
the overall effects on this
character area.
Low
Minor /
Moderate
Beneficial
Minor / Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Minor /
Moderate
Beneficial
At operation
Established
Document1
Low
Low
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Residual Effects on the Visual Resource
11.7.3
Table 11.21 summarises the effect of mitigation measures on the visual resource.
Table 11.21: Residual Impacts on the Visual Resource
Receptor: Viewpoint 1 St Marys Church
Sensitivity: VERY HIGH
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Negligible
Not Significant
No change
Negligible
Not Significant
At Operation
Negligible
Not Significant
No change
Negligible
Not Significant
Established
Negligible
Not Significant
No change
Negligible
Not Significant
Receptor: Viewpoint 2 Old Lloyds Bank
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Moderate
Adverse
No change
Negligible
Moderate
Adverse
At Operation
Medium
Moderate
Adverse
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Negligible
Moderate
Adverse
Negligible
MinorModerate
Beneficial in
relation to the
perceived
condition of the
built form from
this receptor.
MinorModerate
Adverse in
relation to the
perceived
architectural
response to
townscape
setting and
character.
Established
Low
Minor-Moderate
Beneficial in
relation to the
perceived
condition of the
built form from
this receptor
Minor-Moderate
Adverse in
relation to the
perceived
architectural
response to
townscape setting
and character.
Receptor: Viewpoint 3 The Bury
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Sensitivity: HIGH
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Moderate
Adverse
No change
Low
Moderate
Adverse
At Operation
Low
Moderate
Beneficial
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Low
Moderate
Beneficial
Low
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
Low
Moderate
Beneficial
Established
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assessment are delivered.
Receptor: Viewpoint 4 Gadebridge Park.
Eastern Entrance
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Moderate
Adverse
No change
Low
Moderate
Adverse
Medium
Moderate
Beneficial in
relation to the
components of
the view relating
to built form.
Moderate
Adverse in
relation to the
impact on the
components of
the view relating
to green
infrastructure.
The mitigation measures are
unlikely to have a perceptible
effect on this receptor.
Low
Moderate
Beneficial in
relation to the
components of
the view
relating to built
form.
Moderate
Adverse in
relation to the
impact on the
components of
the view
relating to
green
infrastructure.
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Moderate
Beneficial
At Operation
Established
Medium
Receptor: Viewpoint 5 Gadebridge Park.
Western Entrance
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Minor – Moderate
Adverse
No change
Medium
Minor –
Moderate
Adverse
Minor – Moderate
Beneficial
The delivery of a new high
quality college building to the
northwest of the site will have
a further positive effect on this
receptor,
however
the
magnitude
of
change
experienced will remain the
same.
Medium
Minor –
Moderate
Beneficial
Minor – Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Minor –
Moderate
Beneficial
At operation
Established
Document1
Medium
Medium
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Receptor: Viewpoint 6 Century House
Sensitivity: MEDIUM
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Minor-moderate
adverse
No change
Medium
Minor –
Moderate
Adverse
At Operation
Low prior to
completing
the
northwest
college
building.
Medium
upon
completion
of the
northwest
college
building.
Minor – Moderate
Beneficial prior to
the completion of
the northwest
college building.
Moderate
Beneficial upon
completion of the
northwest college
building.
Prior to the completion of the
northwest college building,
proposals to limit light-spill will
be noticeable in the mid-far
distance from this receptor.
The delivery of a new high
quality college building to the
northwest of the site will have
a further positive effect on this
receptor,
however
the
magnitude
of
change
experienced will remain the
same.
Low prior
to
completing
the
northwest
college
building.
Medium
upon
completion
of the
northwest
college
building.
Minor –
Moderate
Beneficial prior
to the
completion of
the northwest
college
building.
Moderate
Beneficial upon
completion of
the northwest
college
building.
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Moderate
Beneficial
Established
Medium
Receptor: Viewpoint 7 Warners End Road
Sensitivity: Low
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Minor-moderate
adverse
No change
Medium
Minor –
Moderate
Adverse
At Operation
Low prior to
completing
the
northwest
college
building.
Medium
upon
completion
of the
northwest
college
building.
Minor-Adverse
prior to the
completion of the
northwest college
building.
Minor – Moderate
Beneficial upon
completion of the
northwest college
building.
Prior to the completion of the
northwest college building,
proposals to limit light-spill will
be noticeable in the mid-far
distance from this receptor.
The delivery of a new high
quality college building to the
northwest of the site will have
a further positive effect on this
receptor,
however
the
magnitude
of
change
experienced will remain the
same.
Low prior
to
completing
the
northwest
college
building.
Medium
upon
completion
of the
northwest
college
building.
Minor –
Adverse prior
to the
completion of
the northwest
college
building.
Minor –
Moderate
Beneficial upon
completion of
the northwest
college
building.
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Moderate
Beneficial
Established
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Medium
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Receptor: Viewpoint 8 78 Bury Road
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Minor Adverse
No change
Medium
MinorModerate
Adverse
Minor Beneficial
The delivery of a new high
quality college building to the
northwest of the site will have
a further positive effect on this
receptor,
however
the
magnitude
of
change
experienced will remain the
same.
Low
Minor
Beneficial
Minor Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Minor
Beneficial
At Operation
Established
Low
Low
Receptor: Viewpoint 9 Leighton Buzzard
Road / Riverside Walk
Sensitivity: Low
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Minor-Moderate
Adverse
No change
Medium
Minor –
Moderate
Adverse
Minor-Moderate
Beneficial
Limiting light spill from the
development will have a small
impact on the extent of
change perceived after dark
from this receptor, however
this is unlikely to affect the
overall magnitude of change
of effects on this receptor.
The effect of limiting light-spill
is likely to have a positive
effect on biodiversity in this
area.
The delivery of high quality,
well-treed east west link may
mitigate for the loss of trees
within the site itself, currently
present in the mid-far distance
to the right-hand side of the
view. However, this is unlikely
to affect the overall magnitude
of change of effects from this
receptor.
Medium
Minor –
Moderate
Beneficial
Minor-Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Minor –
Moderate
Beneficial
At operation
Established
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Medium
Medium
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Receptor: Viewpoint 10 100 BURY ROAD
Sensitivity: HIGH
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Moderate – Major
Adverse
No change
Medium
Minor –
Moderate
Adverse
Medium
Moderate – Major
Beneficial in
relation to the
components of
the view relating
to built form.
Moderate – Major
Adverse in
relation to the
impact on the
components of
the view relating
to green
infrastructure and
the perception of
artificial light after
dark.
Limiting light spill from the
development will have a small
impact on the extent of
change perceived after dark
from this receptor.
Medium
Moderate –
Major
Beneficial in
relation to the
components of
the view
relating to built
form.
Moderate –
Major Adverse
in relation to
the impact on
the
components of
the view
relating to
green
infrastructure.
Moderate
Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Moderate
Beneficial
At operation
Established
Low
Receptor: Viewpoint 11 Water Gardens
North
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Negligible
Not Significant
No change
Negligible
Not Significant
At Operation
Negligible
Not Significant
No change
Negligible
Not Significant
Established
Negligible
Not Significant
No change
Negligible
Not Significant
Receptor: Viewpoint 12 Old Marlowes
House
Sensitivity: HIGH
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Medium
Moderate / Major
Adverse
No change
Medium
Moderate
Adverse
Moderate /Major
Beneficial
The delivery of high quality,
well-treed east west link may
mitigate for the loss of trees
within the site itself, currently
present in the mid-far distance
to the right-hand side of the
view to have a more positive
effect on the view from this
receptor.
However, this is
Medium
Moderate
Beneficial
At Operation
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unlikely to affect the overall
magnitude of change of
effects perceived from this
receptor.
Established
Medium
Moderate / Major
Beneficial
Receptor: Viewpoint 13 Hamilton House
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Medium
Moderate
Beneficial
Sensitivity: LOW
Initial Impact Assessment
Residual Impact Assessment
Scenario
Magnitude
Impact
of Change
Description of Effect
Magnitude
of Change
Residual
Impact
Construction
Low
Minor Adverse
No change
Low
Minor Adverse
Minor Beneficial
The delivery of high quality,
well-treed east west link will
be perceptible in the centre of
the view in the middle
distance and will improve the
overall perception of green
infrastructure in this view.
However, the change will not
have an overall impact on the
magnitude
of
change
perceived from this viewpoint.
Low
Minor
Beneficial
Minor Beneficial
The implementation of a
landscape management and
maintenance plan will aim to
ensure that the potential
effects described in the initial
assessment are delivered.
Low
Minor
Beneficial
At Operation
Established
Low
Low
Summary
11.8.1
The townscape and visual assessment of the proposed development was undertaken in
accordance with accepted best practice guidance.
11.8.2
A study of the townscape and visual components of the site and the local area was
undertaken through desktop study and field visits. This, supported by consultation with
Dacorum Borough Council identified the main landscape and visual receptors to be
considered in this assessment.
11.8.3
The assessment considered was based upon the proposed development outlined in the
application. Therefore, primary mitigation has been integrated into the development
proposals.
11.8.4
Comparing the sensitivity of the receptors to the magnitude of predicted change effecting
each receptor allowed the significance of these impacts to be ascertained during
construction, at operation and when established (15 years after completion). This determined
the main townscape and visual implications of the proposed development and their potential
impacts to be identified.
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11.8.5
The assessment of impacts upon the townscape resource has found:

During the construction phase, each baseline receptor will be affected adversely;
however the duration of this effect is temporary.

At operation, the development is expected to have a beneficial impact on all five
townscape character areas assessed. However, the impact upon the Proposal Site and
Gade Zone is expected to receive moderate adverse impacts in relation to green
infrastructure. the impact on built form in these character areas is expected to beneficial.
adverse impacts have been reduced through mitigation and the provision of a high,
quality, well treed link to the south of the site.

In 15 years’ time, once the proposed vegetation is established, and assuming it has
been well managed and maintained, the proposal is expected to have an overall
moderate beneficial impact on the townscape resource.
11.8.6
As such, the development has been assessed to have an overall moderate beneficial impact
upon townscape character
11.8.7
The assessment of impacts upon the visual resource has found:

During the construction phase, each baseline receptor will be affected adversely;
however the duration of this effect is temporary.

At operation, the development is expected to generally have a beneficial impact on the
visual receptors assessed with the following exceptions;

At operation, the development is expected to generally have a beneficial impact on the
visual receptors assessed with the following exceptions;
 Looking towards the site from Old Lloyds Bank (ALH house) is expected to be
moderate adverse at operation, due to new tree planting at establishment, the
overall impact has been found to be minor-moderate adverse. However, the
proposed buildings are expected to have an overall minor-moderate beneficial
effect in comparison to the existing resource.
 From south eastern entrance to Gadebridge Park on Queensway there may be a
moderate adverse impact on green infrastructure (although moderate beneficial in
relation to the components of the views containing built form).
 From Warners End Road (near Gadebridge Court) is expected to be minor adverse
prior to the completion college building proposed in outline, reducing to minormoderate beneficial. However, on establishment of planting the proposal is
expected to have an overall beneficial impact on the visual resource.
 The impact on 100 Bury Road is expected to be moderate –major adverse in
relation to the impact on the components of the view containing green
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infrastructure. However, once the vegetation established, the impact of changes in
this view are likely to be moderate beneficial.
11.8.8
In the long term, the proposal is likely to have an overall minor to moderate beneficial impact
on the overall townscape and visual resource.
References
Best Practice Guidance

Countryside Agency and Scottish Natural Heritage (2002) Landscape Character
Assessment Guidance for England and Scotland, Cheltenham; The Countryside Agency

Institute of Lighting Engineers (2011) Guidance Notes for the Reduction of Obtrusive
Light;
Internet
reference
accessed
19
April
2013.
Available
from;
https://www.theilp.org.uk/documents/obtrusive-light/

Landscape Institute (LI) and Institute of Environmental Management & Assessment
(IEMA) (2002) Guidelines for Landscape and Visual Impact Assessment 2nd Edition,
London: Spon Press

Landscape Institute (LI) and Institute of Environmental Management & Assessment
(IEMA) (2012) Guidelines for Landscape and Visual Impact Assessment 3rd Edition,
Consultation Draft’ London: LI

Landscape Institute Advice Note (2011) Use of Photography and Photomontage in
Landscape and Visual Assessment, London: Landscape Institute

Scottish Natural Heritage and The Countryside Agency (2002) Landscape Character
Assessment – Guidance for England and Scotland

English Partnerships and The Housing Association (now HCA)(2000). Urban Design
Compendium, London: HCA
General references and baseline studies
Document1

Aboricultural Solutions (2012) Arboricultural Impact Assessment, October 2012

Allies & Morrison, Urban Practitioners and The Landscape Partnership (2011) Water
Gardens Study, October 2011

British Listed Buildings (n.d) British Listed Buildings, Internet reference accessed 19
April 2013. Available from; http://www.britishlistedbuildings.co.uk/map

Dacorum Borough Council (2002) Landscape
Hempstead: Dacorum Borough Council
259
Character
Assessment,
Hemel
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Environmental Statement - Volume 1
Document1

Dacorum Borough Council (1991) Dacorum Borough Local Plan 1991 – 2011, Internet
reference
accessed
19
April
2013.
Available
from;
http://dacorum.addresscafe.com/app/exploreit/

Dacorum Borough Council (2006) Dacorum Urban Design Assessment – Hemel
Hempstead, Hemel Hempstead: Dacorum Borough Council

Dacorum Borough Council (2011) Draft Core Strategy Pre-submission Written
Statement, Hemel Hempstead: Dacorum Borough Council

Dacorum Borough Council (2012) Gade Zone Planning Statement 2012, , Hemel
Hempstead, Dacorum Borough Council, April 2012

Dacorum Borough Council (2012) Hemel Hempstead Old Town Character Appraisal
Consultation Draft, Hemel Hempstead: Dacorum Borough Council, April 2012

Dacorum Borough Council (2012) Draft Core Strategy Pre-submission Omissions
Document, Hemel Hempstead: Dacorum Borough Council

Dacorum Borough Council (2013) Modifications to the Pre-submission Core Strategy,
Hemel Hempstead: Dacorum Borough Council

Dacorum Borough Council (2013) Hemel Hempstead Town Centre Masterplan Hemel
Hempstead: Dacorum Borough Council, August 2013

English Heritage (n.d) The Heritage List for England. Internet reference accessed 19th
April
2013.
Available
from;
http://www.englishheritage.org.uk/professional/protection/process/national-heritage-list-for-england/

Landscape East (2011) East of England Landscape Typology, Landscape East

Ordnance Survey (2010) Ordnance Survey Explorer No. 182, scale 1:25 000,
Southampton: Ordnance Survey

The Countryside Agency (now Natural England) (1998-99) Joint National Character Area
110 ‘The Chilterns’, The Countryside Agency
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12
Transport and Access
Introduction
12.1.1
SKM Colin Buchanan (SKM CB) has been commissioned to undertake a study of the
transport and accessibility effects of the proposed development. The effect of the
‘construction’ and ‘operational’ phases has been assessed in comparison with the baseline
situation in terms of road traffic flows, accessibility and sustainable travel. A separate
Transport Assessment (TA) has also been produced by SKM CB and is submitted as part of
the application material for the proposed development.
12.1.2
This Chapter has been divided into a number of sections which describe the stages of the
assessment process undertaken by SKM CB. The ‘policy context’ section places the
assessment within the context of national and local planning policy. The ‘methodology’
section identifies the methods used to assess the traffic and transportation effects and the
means by which the importance of the effects was determined. The ‘baseline conditions’
section describes the existing local conditions in terms of land use; road network; and
pedestrian, cyclist and public transport facilities. The ‘potential effects’ section considers the
direct and indirect environmental effects of the development arising from the expected trip
generation of the proposed development. The construction phase has also been briefly
considered within this section. The ‘mitigation measures’ section identifies measures,
processes and methods that are proposed in order to prevent, reduce or offset any adverse
environmental effects. The ‘residual effects’ section identifies any effects which remain after
mitigation measures are implemented. A final summary and references are provided at the
end of the report.
Policy Context
Department for Transport White Paper, the Future of Transport – A Network for 2030
12.2.1
Document1
The Government White Paper on the Future of Transport – A Network for 2030 sets out the
Government’s long term aims for the transport network. It considers transport to be essential
to the economy and the way we live, accepting that decisions taken now will have a lasting
impact for decades to come.

freer flowing local roads delivered though measures such as congestion charging;

more, and more reliable buses enjoying more road space;

demand responsive bus services that provide accessibility in areas that cannot support
conventional services;

looking at ways to make services more accessible so that people have a real choice
about when and how they travel;
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
promoting the use of school travel plans, workplace travel plans and personalised
journey planning to encourage people to consider alternatives to using their cars; and

creating a culture and improved quality of local environment so that cycling and walking
are seen as an attractive alternative to car travel for short journeys, particularly for
children.
National Planning Policy Framework, March 2012
12.2.2
The National Planning Policy Framework (NPPF) sets out the Governments planning policies
for England and how they should be applied. It supersedes the previous planning policy
guidance notes including PPG13 and instead promotes a framework that emphasises the
needs of local, sustainable communities.
12.2.3
It highlights the importance transport policies have in facilitating sustainable development
and how they promote wider health and sustainability objectives. The NPPF states that plans
for major developments that generate significant amounts of movement should be supported
by a Transport Statement or Transport Assessment.
12.2.4
Such plans should take account of the following:

the opportunities for sustainable transport modes have been taken up depending on the
nature and location of the site, to reduce the need for major transport infrastructure;

safe and suitable access to the site can be achieved for all people; and

improvements can be undertaken within the transport network that cost effectively limit
the significant impacts of the development. Development should only be prevented or
refused on transport grounds where the residual cumulative impacts of development are
severe.
12.2.5
Plans and decisions should ensure developments that generate significant movement are
located where the need to travel will be minimised and the use of sustainable transport
modes can be maximised.
12.2.6
Plans should protect and exploit opportunities for the use of sustainable transport modes for
the movement of goods or people. Therefore, developments should be located and designed
where practical to:
Document1

accommodate the efficient delivery of goods and supplies;

give priority to pedestrian and cycle movements, and have access to high quality public
transport facilities;

create safe and secure layouts which minimise conflicts between traffic and cyclists or
pedestrians, avoiding street clutter and where appropriate establishing home zones;

incorporate facilities for charging plug-in and other ultra-low emission vehicles; and
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
12.2.7
consider the needs of people with disabilities by all modes of transport.
The NPPF also states that Travel Plans should be provided in order to deliver and promote
sustainable travel objectives. All developments which generate significant amounts of
movement should be required to provide a Travel Plan.
Hertfordshire Local Transport Plan
12.2.8
The third Hertfordshire Local Transport Plan (LTP3) provides a framework for transport’s
support of the economic and social development of Hertfordshire over the next 20 years, and
will influence funding not only for the county council but for all who are engaged in
development and in the provision and use of the transport network.
12.2.9
The overall aim is summarised in Hertfordshire’s Transport Vision statement:
‘To provide a safe, efficient and resilient transport system that serves the needs of business
and residents across Hertfordshire and minimises its impact on the environment.’
12.2.10 The 5 LTP goals which form the basis of the county transport strategy differ little from those
of national guidance. They have been determined as:

Support economic development and planned dwelling growth

Improve transport opportunities for all and achieve behavioural change in mode choice

Enhance quality of life, health and the natural, built and historic environment for all
Hertfordshire residents

Improve the safety and security of residents and other road users

Reduce transport’s contribution to greenhouse gas emissions and improve its resilience.
12.2.11 The relevant challenges set by the LTP3, with regard to the development site include:
Document1

Challenge 1.2: Support economic development and planned dwelling growth- the plan
states that developers should contribute to the long term maintenance of special
highway features and help fund sustainable transport facilities and services.

Challenge 2.1: Improve accessibility, particularly for non-car users and the
disadvantaged- infrastructure improvements, such as pedestrian crossings, should
increase accessibility for all users.

Challenge 2.2: Achieve behavioural change as regards choice of transport modesustainable modes of transport should be promoted through provision of information,
travel planning for the development and improve facilities for sustainable modes.

Challenge 4.1: Improve road safety- ensure new infrastructure improvements are
engineered towards promoting safety and wellbeing of users.
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Dacorum Core Strategy Document)
12.2.12 The council is currently developing a Local Development Framework (LDF) for the borough
which will replace the Local Plan. The Core Strategy Document is the central document of
the LDF.
12.2.13 The purpose of the Core Strategy is to anticipate and manage change in Dacorum up to
2031. It sets the objectives of balancing the need for new development and infrastructure
against the need to maintain the environmental assets and unique character of the borough.
It is identified as one of the key tools to help maximise and co-ordinate new investment in
Dacorum and help promote economic regeneration.
12.2.14 The policies relevant to the development site include:

Policy CS8 Sustainable Transport discusses the need for the development to contribute
to a well-connected and accessible transport system that gives priority to pedestrians
and cyclists. It states that: “Plans should strengthen links between key facilities and
should have good access for people with disabilities. The Development proposal will also
contribute to the implementation of the strategies and priorities set out in the Local
Transport Plan and local Urban Transport Plans”.

Policy CS9 Management of Roads suggests that in Hemel Hempstead “road
improvements will focus on relieving congestion in and around the Maylands Business
Park, including the delivery of a new north-eastern relief route, and improving the
capacity and safety of the Plough Roundabout. Elsewhere, small-scale improvements
will be undertaken to tackle local environmental and safety problems. Local road space
will be shared and designed to allow the safe movement of all users”

Policy CS33 Hemel Hempstead Town Centre is a strategy for Hemel Hempstead Town
centre that has an emphasis on movement which will be considered relevant to the
development proposals. Policies regarding movement relate to providing:

An integrated public transport hub and circulation within the centre

better east-west links, in particular for pedestrians

improve cycling provision
12.2.15 The core strategy is yet to be adopted.
Hemel Hempstead Town Centre Masterplan (2013)
12.2.16 The Hemel Hempstead Town Centre Masterplan sets out Dacorum Council’s goals for the
rejuvenation and redevelopment of the town centre by 2031. The Council consulted
extensively with key stakeholders including representatives of local businesses, landowners,
organisations, community groups and relevant officers from Dacorum Borough Council and
Hertfordshire County Council. Their input identified key issues, aims, objectives, and refined
emerging strategies.
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12.2.17 A draft version of the Hemel Hempstead Masterplan was approved on 24 July 2012 and was
subsequently adopted in January 2013 as a Supplementary Planning Document. The
document provides planning guidance for future development in the town centre to enable
the regeneration of key areas and delivery of key proposals, primarily to improve the vitality
and vibrancy of Hemel Hempstead town centre.
12.2.18 Ten main objectives are identified. The most relevant to transport is:
‘Encourage sustainable access and easy movement to, and within, the town centre allowing
access by all forms of travel, most particularly walking and cycling.’
12.2.19 In order to encourage sustainable access and movement, the town centre Masterplan hopes
to:

Create a more cohesive form of development that promotes sustainable methods of
transport and strengthens links to and between key facilities (bus and railway stations,
the hospital, the town centre and main areas of employment);

Improve linkages and navigation for pedestrian and cycle movement between the railway
station and town centre, and other key destinations;

Incorporate a new bus interchange and appropriate levels of taxi ranking;

Create new north-south and east-west pedestrian and vehicular connections;

Incorporate sufficient and appropriate access, servicing and car parking; and

Improve traffic circulation and optimise town centre functionality.
12.2.20 Within the vicinity of the site, the Masterplan aims to implement the following key
improvements:
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
The bus station will be replaced by a new bus interchange on Bridge Street/Marlowes.

A new road access to the zone can be taken from the Leighton Buzzard Road

East-west links will be improved across the Gade/Original Marlowes Zones through more
and upgraded crossing facilities along the Leighton Buzzard Road.

The Gade and Jellicoe Water Gardens Zones will benefit from the creation of an
attractive and well landscaped north-south cycle and pedestrian route along the River

Gade corridor and improved access and movement across the Market Square.

A new taxi rank will be positioned to the north of Waterhouse Street.

Pedestrians and cyclists will be given priority over vehicles along Waterhouse Street.
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
Links to the Old Town will be strengthened through pedestrian and cycling priority
measures, traffic calming along Queensway and better navigation and signage.

Signage will be improved at key gateway locations around the Leighton Buzzard Road,
Queensway, Combe Street, Bridge Street, Waterhouse Street, Marlowes and Hillfield
Road.
12.2.21 The Masterplan also identified that the Gade Zone presents an opportunity to deliver a new
supermarket in the north of the Zone and that redevelopment of the area will help to
generate activity to the north of the town centre. The Masterplan also identifies that a new
college and food store should be part of the first phase of development for this zone and that
a new food store will support wider regeneration initiatives by attracting people to the area
and improving economic activity.
12.2.22 The River Gade Walk and Cycle Way has also been identified within close proximity to the
proposed site and will aid in improving sustainable travel links in the area.
12.2.23 According to the Masterplan, the new food store will provide a decked car park which will
also be associated with other trips to the town centre. The Gade Zone Planning Statement
discusses the development of the area and in relation to the Transport Assessment
discusses car parking for the zone.
Gade Zone Planning Statement
12.2.24 This Planning Statement takes into account existing emerging planning policy and will help
inform and support developers redevelop the Gade Zone of the Hemel Hempstead Town
Centre Masterplan. The objectives within the planning statement are in line with the Local
Plan and the Pre-submission Core Strategy.
12.2.25 The objectives specific to the Gade Zone, in terms of access and movement are as follows:
Document1

To improve linkages and pedestrian/cycle movement into, through and around the town
centre;

To relocate bus services to create a central bus interchange in order to promote
sustainable transport

To create a continuous riverside walk and cycle way from the Water Gardens to
Gadebridge Park providing improved north-south connectivity.

To create new and enhanced east-west pedestrian and vehicular connections.

To provide key pedestrian and cycle crossings across Leighton Buzzard Road and
Queensway improving linkages with the wider town.

To promote safe highway conditions within and around the site.
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12.2.26 The planning statement identifies the need for the Gade Zone to be better linked to
surrounding areas of the town centre and the open spaces and neighbourhoods beyond.
This should include the provision of better connections and an improvement to pedestrian
and cycle links to adjacent areas. The development must therefore ensure the following
principles are accommodated:

Accommodate safe and convenient connections for pedestrians and cyclists ensuring all
routes are accessible for disabled users.

Create a linked hierarchy of public green spaces along the River Gade corridor forming a
riverside walk and cycle way improving north-south connections through the Gade Zone.

Provide interlinked public spaces throughout the Gade Zone which encourage
movement.

Ensure the layout of the Gade Zone is legible and permeable and connects with adjacent
areas of the town centre and nearby residential neighbourhoods with a particular focus
on east-west links.

Retain the existing Dacorum Way access as a key vehicular route through the Gade
Zone.

Create a better pedestrian/cycle environment along Leighton Buzzard Road and on
Queensway.

Ensure car parking does not dominate the development.
12.2.27 As highlighted in the planning statement as part of redevelopment of the Gade Zone, on-site
delivery or developer contributions will be sought for the following:
Document1
1)
Affordable housing in schemes involving residential development (refer to the Planning
Obligations SPD for more information)
2)
The riverside walk and cycle way
3)
Landscaping in the vicinity of the development (plus on-going maintenance support)
4)
Pedestrian and cycle crossings
5)
Appropriate traffic calming measures, pedestrian and cycle improvements and
highway enhancements within and adjacent to the town centre
6)
Paving wrapping around the Gade Zone (along Queensway and the Marlowes)
7)
Street furniture
8)
The Water Gardens
9)
Improvements to Waterhouse Street and the Market Square
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Methodology
Assessment Methodology
12.3.1
The associated TA has been prepared in accordance with the published DfT’s “Guidance on
Transport Assessment”, and in line with current good practice, focuses on walking, cycling
and public transport. It assesses the potential effects of the Development, which is due for
completion in 2015.
12.3.2
This chapter assesses the two key aspects of transport effects, which are:
12.3.3

The increase in road traffic flows resulting from the proposed development and its effect
on people and vehicular movements on the study area.

The accessibility of the site, focusing on measures aimed at encouraging walking,
cycling and public transport use that will offer wide-ranging benefits, including
inclusiveness and accessibility. Reduced reliance on the motor car will also lessen the
environmental effect of the development in terms of road traffic flows.
Two broad rules, as set out in the IEMA “Guidelines for the Environmental Assessment of
Road Traffic” , are used to assess the effect of road traffic:

Rule 1: Include highway links where traffic flows would increase by more than 30% or
the number of HGVs would increase by more than 30%.

Rule 2: Include any other specifically sensitive areas where traffic flows would increase
by 10% or more.
12.3.4
Other key environmental effects associated with transport are noise and air quality. These
issues are dealt with separately within this ES in Chapters 13 and 14 respectively.
12.3.5
The key highway links considered within this assessment consist of the following, which are
illustrated in Appendix G.2:
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
Link 1: Warners End Road

Link 2: A4146 Leighton Buzzard Road (north of the junction with B487)

Link 3: Queensway (west of the junction with Marlowes)

Link 4: Queensway (east of the junction with Marlowes)

Link 5: Marlowes

Link 6: Marlowes (between Midland Road and Combe Street)

Link 7: Combe Street

Link 8: A4146 Leighton Buzzard Road (south of the junction with Combe Street)
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
Link 9: A4146 Leighton Buzzard Road (from the junction with Combe Street to site
access)

Link 10: A4146 Leighton Buzzard Road (from site access to the junction with B487)
Baseline Traffic Flows
12.3.6
Traffic surveys were undertaken on Friday 19th and Saturday 20th October 2012. These
traffic surveys have been used to determine the traffic generation of the existing use of the
site by West Herts College.
12.3.7
The morning peak hour period was identified as being between 0800-0900 for the evening
peak hour period as 1700-1800 and the Saturday peak hour period of 1100-1200. This
accords with the busiest periods on the highway network for food store land uses. This
survey data was used to model the agreed junctions.
Consultation with DBC and HCC
12.3.8
The scope and methodology of the assessment contained in the TA and referred to within
this chapter has been agreed with the officers from the transportation section of DBC and
Hertfordshire County Council (HCC), as the highway authority.
Assessment Years
12.3.9
The baseline assessment year for this assessment has been defined as 2012; the
operational phase is assessed for 2015 as the year of opening. This conforms to IEMA
guidance that assessment should also be undertaken relative to the first full year of
completion rather than for any period extending into the future.
Future Trip Generation
12.3.10 To estimate the likely trip generation for the proposed Morrison store, SKM CB has derived
trip rates per 100 sq. m Gross Floor Area (GFA) from survey data at Tesco Borehamwood in
Hertfordshire. The use of data derived from the Tesco store as a proxy to estimate likely trip
generation characteristics was discussed and agreed with both DBC and HCC. Traffic
counts were undertaken in February 2011 for a Friday AM and PM and Saturday highway
peak hours.
12.3.11 The redevelopment of the college will comprise of a new facility of a similar size to the
existing college. Although this facility will allow for an increase in staff and student numbers,
the proposed level of parking will be broadly similar to existing levels of parking on site. As a
result, traffic generation is assumed to be the same as the existing situation.
12.3.12 The proposed trip rates and estimated vehicle trip generation for each site element are
highlighted in the section below.
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Vehicle Trip Distribution and Assignment
12.3.13 Table 12.1 presents the summary of the trips generated by the development compared with
the existing traffic generated by the site, notwithstanding the change in access strategy. (For
more detail on how these figures were derived refer to ‘The Link – Transport Assessment’).
Table 12.1: Civic Land Uses Future Traffic Generation (PCUs)
Access
AM (0800-0900)
PM (1700-1800)
Saturday (12001300)
IN
IN
IN
OUT
OUT
OUT
Existing WHC
52
1
1
4
2
8
Existing Civic
259
43
40
87
76
37
TOTAL Existing
311
44
41
91
78
45
Proposed WHC
52
1
1
4
2
8
Proposed
Morrisons
196
139
224
240
324
285
Proposed Civic
197
32
32
57
58
16
Total Proposed
445
172
257
301
384
309
Net Change
134
128
216
149
306
264
12.3.14 The results above show that the greatest increase in traffic generated by the site in the
proposed scenario will occur in the Saturday peak, when background traffic levels are lower
than in the AM and PM peaks. In the AM peak, there will be a net increase in trips of
approximately 130 Passenger Car Unit (PCUs) in each direction. In the PM peak, the site will
generate a net increase in inbound trips of 216 PCUs, and a net increase in outbound trips of
149 PCUs.
Traffic Distribution / Assignment
12.3.15 Two assignment approaches have been adopted to assess the impact of the proposed
development:

The traffic assignment for the opening year (2015) has been undertaken using a spreadsheet based assignment model.

In addition, a traffic assignment exercise has been undertaken using the PARAMICS
model for the town centre for the 2021 future year scenario.
12.3.16 The distribution principals involved in the assignment are consistent between the two
assessment years. However, the PARAMICS modelling assessment has the benefit of being
able to account for the cumulative impact of the full level of town centre developments likely
to be realised post-2015, and the potential for traffic to re-distribute based on existing and
projected congestion on the local and strategic road network.
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12.3.17 For the purpose of the planning application only the spreadsheet assignment has been
assessed. This is due to the fact that the 2021 PARAMICS model includes all of the
proposed Town Centre Masterplan development and some highway infrastructure
improvements to accommodate it.
Link Capacity Assessment
12.3.18 To conform to the assessment methods outlined with IEMA “Guidance on the Environmental
Assessment of Road Traffic”, a Highway Link Capacity assessment has been undertaken for
the development proposals. Detailed junction capacity testing has been undertaken
separately within the TA.
12.3.19 Link capacity assessment is used in this instance as the marginal changes in traffic on the
perceptible environment are less sensitive than changes in traffic flows at junctions in the
surrounding network. This allows for a more direct assessment of changes in traffic levels
which might be deemed significant in environmental terms.
12.3.20 It should be noted that the day-to-day variation of traffic on a road is frequently at least some
+ or -10%. At a basic level, it should therefore be assumed that projected changes in traffic
of less than 10% create no discernible environmental impact. As an example, a perceivable
change in noise nuisance for changes in noise levels can be less than 3 dB(A), which would
require a doubling or halving in the level of traffic. In certain circumstances, a threshold of 1
dB(A) might be deemed appropriate suggesting a significance threshold of around 30%
increase in traffic. The guidance suggests that in particularly sensitive locations, for example
conservation areas, hospitals or links with high pedestrian flows, it might be appropriate to
include those links affected by traffic increases of at least 10%. As a result, the two broad
rules, identified within paragraph 12.3.3, have been used as a guide to assess the effects of
road traffic increases within the link capacity assessments.
12.3.21 For key highway links, a baseline case in terms of link capacity has first been established
which accords with the standards set out within Design Manual for Roads and Bridges
“Traffic Capacity of Urban Roads” (TA 79/99). The IEMA guidance suggests undertaking
separate assessment when there are to be significant phases of a development or where
there is likely to be notable levels of construction traffic. Consequently, changes to the
highway link capacity of surrounding roads as a result of the proposed development have
been assesses for both the ‘construction’ and ‘operational’ phases. These have then been
compared to the baseline conditions to identify the effects of the proposed development and
likely significance in traffic terms.
Junction Capacity Assessment
12.3.22 The Transport Assessment as submitted in support of ‘The Link’ fully details the impact in
the highway network. The 2015 base and proposed traffic flows were entered into junction
models in order to determine the future operation of each junction in 2015. The impact of the
proposed development over the baseline has been considered for each junction.
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12.3.23 Form the analysis undertaken, it has been identified that the proposed development has both
positive and negative impacts when the network is considered as a whole. The following
conclusions can be drawn:

Providing two full lanes southbound on Leighton Buzzard Road alleviates existing
capacity issues on the Leighton Buzzard Road (N) arm of the roundabout with
Queensway.

Additional queuing space is provided to accommodate the increase in southbound queue
on Leighton Buzzard Road at the junction with Combe St.

Change in traffic flow patterns as a result of the new development and civic relocation
results in a small improvement in the RFC at Queensway/Marlowes in the AM peak, but
a small deterioration in RFC in the PM peak.

Increases in traffic associated with the relocation of the civic centre and the proposed
development result in a negative impact on the Leighton Buzzard Road/Combe St.
However the impact is considered to be manageable. Mitigation measures would be
premature to soley accommodate the proposed development in 2015. The 2021
PARAMICS analysis will allow a holistic analysis of the impact of the full Town Centre
Masterplan and full range of mitigation measures required for the Town Centre as a
whole.
12.3.24 In summary, SKM CB considers that no mitigation in excess of providing two full southbound
lanes on Leighton Buzzard Road should be required to accommodate the proposed
development in 2015.
Significance Criteria
12.3.25 The critical feature of an assessment of traffic impacts is determining whether a given impact
is significant. Having identified the magnitude of the impact there are various ways of
interpreting whether or not this is considered significant. The two broad rules outlined in
paragraph 12.3.3 provide a starting guide for this.
12.3.26 A key element here is that for many effects there are no simple rules or formulae that define
thresholds of significance within an EIA. Whether an impact is considered significant will
depend on the level of development traffic activity, the level of traffic already on the
surrounding network, the level of traffic congestion in the area and the environmental setting
within which the development and its associated traffic is located. There is therefore a need
for interpretation and professional judgement, backed up by data or qualified information
where possible.
12.3.27 Table 12.2 outlines an established set of significance criteria and represents a starting point
for identifying the significance of potential traffic impacts.
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Table 12.2: Significance of effects in relation to traffic impacts
Magnitude of
Impact
Increase in
Traffic Flow
Typical Criteria Descriptors
Major
Above 90%
Only adverse effects are assigned this level of importance as they
represent key factors in the decision-making process. These
effects are generally, but not exclusively, associated with sites and
features of international, national or regional importance. A
change at a regional or borough scale site or feature may also
enter this category.
Moderate
Between 60%
and 90%
These effects are likely to be important considerations at a local or
borough scale but, if adverse, are potential concerns to the project
and may become key factors in the decision-making process.
Minor
Between 30%
and 60%
These effects, if adverse, while important at a local scale, are not
likely to be key decision-making issues. Nevertheless, the
cumulative effect of such issues may lead to an increase in the
overall effects on a particular area or on a particular resource.
Negligible
Under 30%
These effects may be raised as local issues but are unlikely to be
of importance in the decision-making process.
Source: adopted from the “Guidelines for the Environmental Assessment of Road Traffic” (Institute of Environmental
Assessment, 1991)
12.3.28 Where a link exhibits existing traffic levels which are exceptionally low, any increase in traffic
flow is likely to result in a predicted increase in traffic levels which exceeds these
significance thresholds. Where this situation is identified it is important to consider any
increase both in terms of its relative increase in respect of existing traffic flows, as well as the
overall total flow in respect of the available capacity of the section of road being considered.
For example, a 100% increase in traffic flow on a road which currently only carries 40
vehicles in a peak hour period would potentially indicate a major significance effect, if it were
considered simply in terms of the IEMA guidelines as shown in Table 12.2.
12.3.29 However, a typical 7.3 m wide road is capable of accommodating approximately 1300
vehicles per hour in each direction, in accordance with guidance contained within Design
Manual for Roads and Bridges (DMRB) TA 46/9746. Therefore, such an increase would be
unlikely to create major effects given the road’s overall capacity.
Baseline Conditions
Site Location
12.4.1
The site is located in the town of Hemel Hempstead, south west Hertfordshire, approximately
5.6 km (3.5 miles) from junction 8 of the M1. More specifically, it is located north-west Hemel
Hempstead town centre, as presented in Appendix G.1.
12.4.2
The M1 motorway is the major route into London from the north. The development site is
bound by the principle roads of the A4116 Leighton Buzzard road to the west and B487
Queensway directly north of the site. The site is further bound by the internal town centre
roads of Marlowes to the east and Combe Street to the south.
46
Design Manual for Roads and Bridges (DMRB) Volume 5, Section 1, Part 3: TA46/97: Traffic Flow Ranges for
Use in the Assessment of New Rural Roads.
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Walking Facilities
12.4.3
The site benefits from a network of pedestrian footways and crossing facilities on the roads
surrounding the site and throughout the town centre. However, the quality of the facilities
varies throughout the town.
12.4.4
There are also a number of signalised pedestrian crossings provided across the major
pedestrian routes through the town, adjacent to the site. including; Leighton Buzzard
Road/Queensway,
Queensway/Marlowes,
Combe
St/Waterhouse
St.,
Leighton
Buzzard/Combe St.
12.4.5
Pedestrian signage in the vicinity of the site is relatively good. There are several examples of
way-finding posts that give directions and distances towards local facilities such as the civic
centre, police station, and the town centre. These help to improve navigation through the
town. There are also maps throughout the town which help pedestrians find their way around
the town and surrounding area
Cycling Facilities
12.4.6
Cycle facilities in Hemel Hempstead are limited. There are no marked cycle lanes around the
town and currently only one major cycle route, National Route 57, connecting Chesham to
Cricklade. National Route 57 is accessible to the north east of the town via a signposted
route from the town centre.
12.4.7
The Dacorum Cycling Strategy (2009) highlights that Hemel Hempstead has benefitted from
cycle provision in the past under the Hemel Hempstead Transportation Plan which provided
advisory routes between:

Leverstock Green and Nash Mills;

Maylands and the town centre via Adeyfield;

Town centre and Maylands via Highfield; and

Town centre and Gadebridge via Gadebridge Park.
12.4.8
Cyclists can also share the bus access from the Plough Roundabout and the bus lanes in
Marlowes, though they are precluded from cycling in the pedestrianised area. However these
routes would benefit from greater publicity, signage and mapping.
12.4.9
Cycle parking is provided at most destinations, but in general would benefit from
improvement and further investment.
12.4.10 The Dacorum Cycling Strategy (2009) also states that new developments are envisaged for
the Town Centre and Maylands, which include enhancements to provisions for cyclists as an
integral part of the plans.
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Bus Services
12.4.11 There are four main bus stops located adjacent to the site on Queensway and Marlowes.
These are within the CIHT maximum recommended walking distance to a bus stop of 400m,
as set out in “Providing for public transport for developments”.
12.4.12 The shelters at these stops are generally very good, providing maps, timetables and free
interactive mobile services that can be used to inform passengers of service updates.
12.4.13 There is also a bus station located in the centre of the town on Waterhouse Street, just a 6
minute walk from the site. This enhances the attractiveness of access to the site by public
transport. A secondary bus hub is located outside Hemel Hempstead railway station;
approximately 30 minute walk from the site.
12.4.14 Table 12.3 displays each service that calls at either Hemel Hempstead Bus Station or
Railway station.
Table 12.3: Summary of bus services in Hemel Hempstead
Bus
Number
Route
Frequency
Mon-Fri
Sat
Sun
Operator
1/1a
Hemel Hempstead – Adeyfield
(circular)
2/hr
2/hr
-
Arriva
2
Woodhall Farm - Chaulden
2-3/hr
2/hr
1/hr
Arriva/Redline
Buses
3
Woodhall Farm - Chaulden
2-3/hr
2/hr
1/hr
Arriva/Redline
Buses
4/5
Grovehill - Nash Mills
(Circular)
2/hr
2/hr
1/hr
Arriva
30/31
Hemel-Hempstead- Aldbury
2/day
2/day
-
Red Eagle
32
Hemel-Hempstead- Aldbury
6/day
2/day
-
Red Eagle
46
Luton - Hemel Hempstead
1/hr
1/hr
-
Centrebus
51
Hemel Hempstead –
Bovingdon
1/day
-
-
Arriva
101
Hemel Hempstead - Jarman
Park
3/hr
-
-
Arriva
175
Edlesborough - Hemel
Hempstead (Thursday only)
1/day
-
-
Redline Buses
207
Long Marston - Hemel
Hempstead (Friday only)
1/day
-
-
Community Action
Dacorum
208
Trowley Bottom - Hemel
Hempstead
1/day
-
-
Community Action
Dacorum
300/301
Stevenage - Hemel
Hempstead
3-9/hr
3/hr
1/hr
Arriva/Uno
318
Hemel Hempstead - Watford
1/hr
-
-
Mullany’s Buses
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320
Hemel Hempstead Rickmansworth/Maple Cross
2-4/hr
2/hr
1/hr
Arriva
352
Watford - Hemel Hempstead
Every 2
hrs
Every
2 hrs
-
Red Route
353
Hemel Hempstead - Slough
1/hr
1/hr
Every
2 hrs
Arriva
500/501
Aylesbury – Watford
4/hr
2/hr
1/hr
Arriva/Red Rose
502/532
Northchurch - Hemel
Hempstead
1/hr
1/hr
-
Little Jim’s Buses
550
Borehamwood - Hemel
Hempstead
2/hr
2/hr
-
Arriva
600
Bennetts End - Chaulden
3/day
-
-
Arriva
634
Hemel Hempstead - Hatfield
1/day
-
-
Uno
707
Northampton - Gatwick Airport
Every 2
hrs
Every
2 hrs
Every
2 hrs
National Express
Bus
Number
Route
Mon-Fri
Sat
Sun
737
Oxford-Stansted Airport
Every 2
hrs
Every
2 hrs
Every
2 hrs
National Express
758/748/
759/768/
769
Redbourn/Hemel Hempstead
– London
1/hr
Every
2 hrs
-
Greenline
787
Cambridge - Heathrow Airport
Every 2
hrs
-
-
National Express
H10
Hemel Hempstead Boxmoor/Leverstock Green
1/hr
1/hr
-
Red Rose
H11
Boxmoor - Chambersbury
Lane
1/hr
1/hr
-
Lanes Coaches/
Red Rose
H13
Hemel Hempstead Rly Stn –
Maylands
4/day
-
-
Arriva
H19
Abbots Langley - Hemel
Hempstead
1/day
-
-
Arriva
NHS1/
NHS2
Hemel Hempstead - Watford
3/day
3/day
3/day
Minibus Executive
Travel
PB1 (AM)
PB2 (PM)
Maylands - Hemel Hempstead
Railway Stn
4/day
-
-
Minibus Executive
Travel
Frequency
Operator
5/day
X31
Luton - Hemel Hempstead
Every 2
hrs
Every
2
hours
Centrebus
12.4.15 The bus stops at both the Bus Station and Hemel Hempstead Rail Station are of an
adequate standard, providing shelter and real time information screens that inform
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passengers with approximate arrival times for services. There are also free interactive
terminals that allow passengers to access journey planning websites such as Traveline,
Transport Direct and National Rail. These facilities make planning journeys accessible. It is
noted that the Town Centre Masterplan seeks to provide a replacement bus station facility on
Marlowes south of the development site.
Train Services
12.4.16 Hemel Hempstead railway station is approximately 2.4km (1.5 miles) from the town centre
train station; roughly a 6 minute drive or half an hour walk from the site. The station is served
by both London Midland and Southern Railway, providing regular services to many
destinations such as Milton Keynes, Northampton, Birmingham, Clapham, Croydon, London
Euston and Brighton. Table 12.4 below summarises each of the services and their
frequency.
Table 12.4 Summary of rail services from Hemel Hempstead train station
Operator
London Midland
Southern Railways
Destination
Frequency
Mon-Fri
Sat
Sun
London Euston
4/hr
4/hr
3/hr
Northampton
1/hr
1/hr
1/hr
Milton Keynes
2/hr
2/hr
2/hr
Birmingham
3/day
6/day
1/hr
Tring
3/hr
3/hr
2/hr
Watford
4/hr
4/hr
2/hr
Rugby
5/day
7/day
1/hr
Milton Keynes
1/hr
1/hr
-
Clapham
1/hr
1/hr
-
Tring
1/hr
1/hr
-
South Croydon
1/hr
1/hr
-
Watford
1/hr
1/hr
-
12.4.17 The station provides a 24 hour car park that has 496 spaces; 11 of which are disabled
spaces. There is a taxi rank and a bus hub that has several services calling/terminating as
discussed previously. There is also provision of 12 sheltered cycle spaces. The station is
accessible on foot, providing adequate footpaths and crossing facilities across London Road.
Road Link Description
12.4.18 The following key links (see Appendix G.2) have been defined for the study area:

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Link 1: Warners End Road. Link 1 is the section of Warners End Road which connects
to the junction with the A4146 Leighton Buzzard Road. It has been classified as a road
type UAP3 classification (from DMRB TA 46/97) with a link capacity of 1300 vehicles
(one-way hourly flow). The link slopes gently down to the junction with the A4146 and
has wide footways on either side of the carriageway. There is a 7.5 tonne lorry
restriction on this link.
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
Link 2: A4146 Leighton Buzzard Road, north of the junction with B487. A4116
Leighton Buzzard Road is another major route into London for commuters, connecting
Leighton Buzzard to the centre of Hemel Hempstead. The road speed on this section is
50mph. It is a single carriageway that runs past the west of the site in a north-south
direction. This has been classified as a road type UAP1 classification with a link
capacity of 1590 vehicles (one-way hourly flow). There are no footways along the side
of the carriageway on this link.

Link 3: Queensway, west of the junction with Marlowes. Link 3 is the B487
Queensway, which is single lane eastbound and two lanes westbound. There is a
standard footway on the southern side of the carriageway but no footway on the northern
side. This has been classified as a road type UAP3 classification with a link capacity of
1300 vehicles eastbound and 1620 vehicles westbound (one-way hourly flows).

Link 4: Queensway, east of the junction with Marlowes. This section of Queensway
leads east of the junction with Marlowes. It is a 30mph single carriageway road that has
a number of side roads, several drop-kerb crossings and a zebra crossing further into
the town to aid pedestrian access. There are active frontages on either side of the road
as it approaches the central area. There is also a bus stop located on the route heading
into the town. It has been classified as a road type UAP4 classification with a link
capacity of 1140 vehicles (one-way hourly flow).

Link 5: Marlowes. Marlowes is a single carriageway road with on-street parking on the
left hand side. There are bus stops on both sides and kerb build-outs with signalised
pedestrian crossings to aid pedestrian access through the town. This has been
classified as a road type UAP4 classification and due to its nature as high street has a
link capacity of 900 vehicles (one-way hourly flow).

Link 6: Marlowes between Midland Road and Combe Street. Link 6 is characterised
by single carriageways northbound and southbound separated by a central median.
This section of Marlowes has wide footways and a northbound bus stop. It has been
classified as a road type UAP4 classification with a link capacity of 1140 vehicles (oneway hourly flow) northbound and 1320 vehicles (one-way hourly flow) southbound.

Link 7: Combe Street. This is a single carriageway road that runs east to west,
connecting Marlowes with the A4116. There are several crossing points along this road
in the form of dropped kerbs and a signalised crossing at the mini-roundabout where the
road connects to Marlowes. Combe Street has been classified as a road type UAP4
classification with a link capacity of 1320 vehicles (one-way hourly flow).

Link 8: A4146 Leighton Buzzard Road, south of the junction with Combe Street.
This section of Leighton Buzzard runs south of the junction with Combe Street. It has
been classified as a road type UAP2 classification with a link capacity of 1385 vehicles.

Link 9: A4146 Leighton Buzzard Road. This link runs from the junction with Combe
Street to site access. It has been classified as UAP2 with a link capacity of 1300
vehicles.
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
Link 10: A4146 Leighton Buzzard Road. This section of Leighton Buzzard Road runs
from site access to the junction with B487. It has been classified as UAP2 with a link
capacity of 1300 vehicles.
Baseline Link Capacity Assessment
12.4.19 The analysis in this section identifies the current baseline capacity on the ten links identified
in paragraph 12.4.18. Tables 12.5, 12.6 and 12.7 cover the AM, PM and Saturday
assessments respectively.
Link 1: Warners End Road
AM
Link 2: A4146 Leighton
Buzzard Road, north of jnt
with B487
AM
Link 3: Queensway, west
of jnt with Marlowes
AM
Link 4: Queensway, east of
jnt with Marlowes
AM
Link 5: Marlowes, btw
Queensway and Midland
Road
AM
Link 6: Marlowes, btw
Midland Road and Combe
Street
AM
Link 7: Combe Street
AM
Link 8: A4146 Leighton
Buzzard Road, south of jnt
with Combe Street
AM
Link 9: A4146 Leighton
Buzzard Road, from
Combe Street to the site
access
AM
Link 10: A4146 Leighton
Buzzard Road, from site
access to B487 jnt
AM
RFC*
Link
Capacity
Road Type
Peak
Link
Baseline
flow
(PCU/hr)
Direction
Table 12.5: Baseline Link Capacity AM (0800 – 0900)
EB
970
UAP3
1300
74.6%
WB
674
UAP3
1300
51.8%
NB
565
UAP1
1590
35.5%
SB
905
UAP1
1590
56.9%
EB
1125
UAP3
1300
86.5%
WB
689
UAP3
1620
42.5%
EB
875
UAP4
1140
76.8%
WB
778
UAP4
1140
68.2%
NB
389
UAP4
900
43.2%
SB
651
UAP4
900
72.3%
NB
468
UAP4
1140
41.1%
SB
621
UAP4
1320
47.0%
EB
581
UAP4
1320
44.0%
WB
361
UAP4
1320
27.3%
NB
1118
UAP2
1385
80.7%
SB
1080
UAP2
1385
78.0%
NB
763
UAP2
1300
58.7%
SB
960
UAP2
1300
73.8%
NB
772
UAP2
1300
59.4%
SB
972
UAP2
1300
74.8%
*Ratio of Flow to Capacity
12.4.20 Table 12.5 shows that during the AM Peak all links are currently operating under capacity
with the highest RFC being the Queensway (WB) link, west of the Marlowes junction, which
is operating at 86.5% RFC, but well below the link capacity.
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Link 1: Warners End Road
PM
Link 2: A4146 Leighton Buzzard
Road, north of jnt with B487
PM
Link 3: Queensway, west of jnt with
Marlowes
PM
Link 4: Queensway, east of jnt with
Marlowes
PM
Link 5: Marlowes, btw Queensway
and Midland Road
PM
Link 6: Marlowes, btw Midland Road
and Combe Street
PM
Link 7: Combe Street
PM
Link 8: A4146 Leighton Buzzard
Road, south of jnt with Combe
Street
PM
Link 9: A4146 Leighton Buzzard
Road, from Combe Street to the site
access
PM
Link 10: A4146 Leighton Buzzard
Road, from site access to B487 jnt
PM
RFC
Link
Capacity
Road Type
Peak
Link
Baseline
flow
(PCU/hr)
Direction
Table 12.6: Baseline Link Capacity PM (1700 – 1800)
EB
562
UAP3
1300
43.2%
WB
953
UAP3
1300
73.3%
NB
875
UAP1
1590
55.0%
SB
642
UAP1
1590
40.4%
EB
588
UAP3
1300
45.2%
WB
1008
UAP3
1620
62.2%
EB
824
UAP4
1140
72.3%
WB
879
UAP4
1140
77.1%
NB
763
UAP4
900
84.8%
SB
379
UAP4
900
42.1%
NB
680
UAP4
1140
59.6%
SB
505
UAP4
1320
38.3%
EB
390
UAP4
1320
29.5%
WB
701
UAP4
1320
53.1%
NB
1049
UAP2
1385
75.7%
SB
1017
UAP2
1385
73.4%
NB
1022
UAP2
1300
78.6%
SB
790
UAP2
1300
60.8%
NB
1015
UAP2
1300
78.1%
SB
811
UAP2
1300
62.4%
12.4.21 Table 12.6 shows that during the PM Peak all links are currently operating under capacity
with the highest RFC being the Marlowes (NB) link, between the Queensway and Midland
Road junctions, which is operating at 84.8% RFC.
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Link 1: Warners End
Road
Sat
Link 2: A4146 Leighton
Buzzard Road, north of
jnt with B487
Sat
Link 3: Queensway, west
of jnt with Marlowes
Sat
Link 4: Queensway, east
of jnt with Marlowes
Sat
Link 5: Marlowes, btw
Queensway and Midland
Road
Sat
Link 6: Marlowes, btw
Midland Road and
Combe Street
Sat
Link 7: Combe Street
Sat
Link 8: A4146 Leighton
Buzzard Road, south of
jnt with Combe Street
Sat
Link 9: A4146 Leighton
Buzzard Road, from
Combe Street to the site
access
Sat
Link 10: A4146 Leighton
Buzzard Road, from site
access to B487 jnt
Sat
RFC
Link
Capacity
Road Type
Peak
Link
Baseline
flow
(PCU/hr)
Direction
Table 12.7: Baseline Link Capacity Saturday (1200 – 1300)
EB
575
UAP3
1300
44.2%
WB
680
UAP3
1300
52.3%
NB
685
UAP1
1590
43.1%
SB
811
UAP1
1590
51.0%
EB
642
UAP3
1300
49.4%
WB
731
UAP3
1620
45.1%
EB
712
UAP4
1140
62.5%
WB
668
UAP4
1140
58.6%
NB
618
UAP4
900
68.7%
SB
494
UAP4
900
54.8%
NB
595
UAP4
1140
52.2%
SB
637
UAP4
1320
48.3%
EB
603
UAP4
1320
45.6%
WB
595
UAP4
1320
45.1%
NB
1013
UAP2
1385
73.2%
SB
1028
UAP2
1385
74.2%
NB
802
UAP2
1300
61.7%
SB
889
UAP2
1300
68.4%
NB
805
UAP2
1300
61.9%
SB
914
UAP2
1300
70.3%
12.4.22 Table 12.7 shows that during the Saturday Peak all links are currently operating under
capacity with the highest RFC being the A4146 Leighton Buzzard Road (NB) link, south of
the Combe Street junction, which is operating at 74.2% RFC.
Potential Effects
Construction
12.5.1
Construction traffic and accessibility effects are related to the arrival and departure of
construction workers and material/waste, and the impact on existing walking and cycling
routes in the area.
12.5.2
Construction traffic will arrive directly from the strategic road network (via the new A4146
Leighton Buzzard Road) to minimise the potential for conflict with pedestrians. The timing of
the arrival / departure of construction traffic would be such that ‘long load’ vehicles will not be
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permitted to access the site during peak periods. This will limit the effect of construction
traffic on the highway network during these periods.
12.5.3
The construction phase will be subject to a detailed Construction Traffic Management Plan
(CTMP) that will be agreed between the appointed contractor and the highway authority.
The CTMP will provide details of amongst other things: the routes than vehicles will take
when accessing the site; information on un/loading areas; whether or not a construction
compound will be utilised and where this will be located; measures to reduce dust and
debris; and hours of operation.
12.5.4
In terms of the number and type of vehicles on the highway these are likely to be much lower
than those associated with the development itself and as such will have a minor adverse
impact.
Operational: Bus trips
12.5.5
The purpose of this section is to consider the impact of the proposed development on other
modes. The main impact in the peak hours will occur on the public transport as a result of
the increased number of staff and students attending the college. Table 12.4 presents these
increases.
Table 12.4: Existing and projected staff and student numbers
Existing no’s
Projected no’s
Staff
95
160
Staff – FTE’s
60
110
Students – Fulltime
500
1100
Students – Part time
1300
2200
12.5.6
It is assumed that loadings on the public transport network will not be materially affected by
the food store owing to potential customers already being on the network to visit stores
elsewhere. Public transport users are also more likely to undertake linked trips, i.e. visiting
the store and the town centre. This assessment therefore concentrates on the impact of the
increased college intake.
12.5.7
In assessing the impact of the increases identified in Table 12.4, as no additional parking is
proposed for the WHC, it is reasonable and robust to assume that all increases will need to
be accommodated on public transport, or other sustainable modes.
Operational: College Mode Split
12.5.8
Whilst vehicle trips to the college are not anticipated to change, it is anticipated that student
numbers will increase and therefore non-car based trips to the college will also increase.
However, these will be dispersed throughout the day rather than concentrated at peak
periods as college space is better utilised to accommodate increases in student/staff.
12.5.9
The existing staff and student mode splits for travel to the college site has been provided by
WHC. This is shown in Table 12.5.
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Table 12.5: WHC Existing Mode Split
Mode of Travel
Student Mode Split %
Staff Mode Split %
Car driver
30
80
Car passenger
10
3
Bus
25
2
Motorcycle
2
1
Bicycle
5
5
Walking
10
6
Train
15
3
Other
3
0
12.5.10 Whilst in all reality arrivals/departures of students will occur throughout the day, for a robust
assessment it has been assumed of that the following arrive in the am peak:

25% of full time additional students (150)

15% of part time additional students (135)

25% of staff FTE’s (13)
12.5.11 This equates to an additional 300 trips by other modes in the am peak hour period. Based
on the existing modal split as identified above, this equates to approximately 75 additional
bus trips per hour or less than 4 passengers per bus service.
12.5.12 In all likelihood, these public transport trips would be spread across a longer time period and
a wider number of bus services which serve a wider area and stop at the Hemel Hempstead
bus station.
12.5.13 Given the average increase in patronage per bus is likely to be only 4 persons per bus, it can
be concluded that the increase in bus use is unlikely to have and environmental effect as no
additional buses will be required.
Operational: Traffic generation
12.5.14 The proposed development comprises of two main land uses and the trips associated with
these have been calculated. As agreed with highway officers, trips generation was based
upon traffic counts at the Tesco, Borehamwood store undertaken in February 2011 for a
Friday and Saturday, trip rates per 100 sq. m GFA have been determined. The trip rates for
the typical Friday AM and PM and Saturday highway peak hours are presented below in
Table 12.8.
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Table 12.8 Supermarket trip rates (GFA) as calculated from Tesco site survey (PCUs)
Peak hour
Arrivals
Departures
Total
Friday AM Peak Hour (08:00-09:00)
4.482
3.187
7.669
Friday PM Peak Hour (17:00-18:00)
5.124
5.486
10.611
Saturday Peak Hour (11:00-12:00)
7.412
6.513
13.926
12.5.15 These trip rates have then been applied to the proposed store to produced estimated levels
of vehicle trip generation which is presented in Table 12.9.
Table 12.9: Calculated Supermarket trips as calculated from Tesco site survey (PCUs)
Peak hour
Arrivals
Departures
Total
Friday AM Peak Hour (08:00-09:00)
196
139
335
Friday PM Peak Hour (17:00-18:00)
224
240
464
Saturday Peak Hour (11:00-12:00)
324
285
609
12.5.16 The existing college traffic generation has been captured by the traffic surveys and can be
seen in Table 12.10 below.
Table 12.10: WHC Trips as Derived from Site Access Survey (PCUs)
Peak hour
Arrivals
Departures
Total
Friday AM Peak Hour (08:00-09:00)
52
1
53
Friday PM Peak Hour (17:00-18:00)
1
4
5
Saturday Peak Hour (11:00-12:00)
2
8
10
12.5.17 It can be seen that the WHC campus will result in 52 inbound arrivals in the AM peak, with
minimal traffic generated in other peaks.
Operational: Highways Link Assessment
12.5.18 The analysis in this section identifies the current baseline capacity on the ten links identified
in paragraph 12.4.18. Table 12.11, 12.12 and 12.13 cover the AM, PM and Saturday
development scenario assessments respectively.
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Link 1: Warners End Road
AM
Link 2: A4146 Leighton
Buzzard Road, north of jnt
with B487
AM
Link 3: Queensway, west of
jnt with Marlowes
AM
Link 4: Queensway, east of
jnt with Marlowes
AM
Link 5: Marlowes, btw
Queensway and Midland
Road
AM
Link 6: Marlowes, btw
Midland Road and Combe
Street
AM
Link 7: Combe Street
AM
Link 8: A4146 Leighton
Buzzard Road, south of jnt
with Combe Street
AM
Link 9: A4146 Leighton
Buzzard Road, from Combe
Street to the site access
AM
Link 10: A4146 Leighton
Buzzard Road, from site
access to B487 jnt
AM
% Change
Peak Hour
Difference
RFC
Operational
2015
(PCU/hr)
RFC
Peak
Link
Baseline
flow
(PCU/hr)
Direction
Table 12.11: 2015 Link Assessment AM (0800 – 0900)
EB
970
74.6%
982
75.6%
12
1.3%
WB
674
51.8%
683
52.5%
9
1.3%
NB
565
35.5%
565
35.6%
0
0.0%
SB
905
56.9%
942
59.2%
37
4.1%
EB
1125
86.5%
1123
86.4%
-2
-0.2%
WB
689
42.5%
770
47.5%
81
11.7
%
EB
875
76.8%
955
83.8%
80
9.1%
WB
778
68.2%
807
70.8%
29
3.7%
NB
389
43.2%
410
45.5%
21
5.4%
SB
651
72.3%
589
65.4%
-62
-9.5%
NB
468
41.1%
467
40.9%
-1
-0.3%
SB
621
47.0%
677
51.3%
56
9.0%
EB
581
44.0%
636
48.1%
55
9.4%
WB
361
27.3%
365
27.7%
4
1.1%
NB
1118
80.7%
1187
85.7%
69
6.2%
SB
1080
78.0%
1122
81.0%
42
3.9%
NB
763
58.7%
744
57.2%
-19
-2.5%
SB
960
73.8%
1057
81.3%
97
10.1
%
NB
772
59.4%
813
62.5%
41
5.3%
SB
972
74.8%
1136
87.4%
164
16.8
%
12.5.19 It can be seen in Table 12.11 above that during the proposed opening year of 2015 all links
on the local road network will operate within their capacity during the AM Peak. However, the
analysis shows the A4146 Leighton Buzzard Road (SB) will increase to 87.4% RFC in the
future scenario and will therefore be approaching capacity, although not to detrimental levels
12.5.20 The table also compares the RFC from the recorded baseline to give a measure of the
impact the development will have on the surrounding links during the proposed opening
year. The largest percentage increase in link flow (16.8%) occurs on the A4146 Leighton
Buzzard Road (SB).
12.5.21 For all the links assessed, the increase in flows is below the 30% ‘flow increase threshold of
concern’ for links not classified as sensitive set out in the Institute of Environmental
Assessment guidance. Therefore it can be concluded that the increase in traffic due to the
development is not a significant environmental issue.
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Link 1: Warners End Road
PM
Link 2: A4146 Leighton Buzzard
Road, north of jnt with B487
PM
Link 3: Queensway, west of jnt with
Marlowes
PM
Link 4: Queensway, east of jnt with
Marlowes
PM
Link 5: Marlowes, btw Queensway
and Midland Road
PM
Link 6: Marlowes, btw Midland Road
and Combe Street
PM
Link 7: Combe Street
PM
Link 8: A4146 Leighton Buzzard
Road, south of jnt with Combe Street
PM
Link 9: A4146 Leighton Buzzard
Road, from Combe Street to the site
access
PM
Link 10: A4146 Leighton Buzzard
Road, from site access to B487 jnt
PM
% Change
Peak Hour
Difference
RFC
Operational
2015
(PCU/hr)
RFC
Baseline
flow
(PCU/hr)
Peak
Link
Direction
Table: 12.12: 2015 Link Assessment PM (1700 – 1800)
EB
562
43.2%
576
44.3%
14
2.5%
WB
953
73.3%
968
74.5%
15
1.6%
NB
875
55.0%
846
53.2%
-29
-3.3%
SB
642
40.4%
664
41.8%
22
3.4%
EB
588
45.2%
702
54.0%
114
19.4%
WB
1008
62.2%
1047
64.6%
39
3.9%
EB
824
72.3%
922
80.9%
98
11.9%
WB
879
77.1%
929
81.5%
50
5.7%
NB
763
84.8%
774
86.0%
11
1.5%
SB
379
42.1%
414
46.1%
35
9.4%
NB
680
59.6%
705
61.9%
25
3.7%
SB
505
38.3%
500
37.9%
-5
-1.0%
EB
390
29.5%
394
29.8%
4
1.0%
WB
701
53.1%
720
54.6%
19
2.8%
NB
1049
75.7%
1099
79.3%
50
4.7%
SB
1017
73.4%
1075
77.6%
58
5.7%
NB
1022
78.6%
985
75.8%
-37
-3.6%
SB
790
60.8%
840
64.6%
50
6.3%
NB
1015
78.1%
1083
83.3%
68
6.7%
SB
811
62.4%
854
65.7%
43
5.2%
12.5.22 It can be seen in Table 12.12 above that during the proposed opening year of 2015 all links
on the local road network will operate within their capacity During the PM Peak. However,
the analysis shows that the Marlowes Link, between the Queensway and Midland Road
junctions, which will increase to 86.0% in the future scenario and will therefore be
approaching capacity, although not to detrimental levels
12.5.23 The table also compares the RFC from the recorded baseline to give a measure of the
impact the development will have on the surrounding links during the proposed opening
year. The largest percentage increase in link flow (19.4%) occurs on the Queensway link,
west of the Marlowes junction (EB).
12.5.24 For all the links assessed, the increase in flows is below the 30% ‘flow increase threshold of
concern’ for links not classified as sensitive set out in the Institute of Environmental
Assessment guidance. Therefore it can be concluded that the increase in traffic due to the
development is not a significant environmental issue.
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Link 1: Warners End Road
Sat
Link 2: A4146 Leighton Buzzard
Road, north of jnt with B487
Sat
Link 3: Queensway, west of jnt with
Marlowes
Sat
Link 4: Queensway, east of jnt with
Marlowes
Sat
Link 5: Marlowes, btw Queensway
and Midland Road
Sat
Link 6: Marlowes, btw Midland Road
and Combe Street
Sat
Link 7: Combe Street
Sat
Link 8: A4146 Leighton Buzzard
Road, south of jnt with Combe Street
Sat
Link 9: A4146 Leighton Buzzard
Road, from Combe Street to the site
access
Sat
Link 10: A4146 Leighton Buzzard
Road, from site access to B487 jnt
Sat
% Change
Peak Hour
Difference
RFC
Operational
2015
(PCU/hr)
RFC
Baseline
flow
(PCU/hr)
Peak
Link
Direction
Table: 12.13 - 2015 Link Assessment SAT (1200 – 1300)
EB
575
44.2%
592
45.5%
17
3.0%
WB
680
52.3%
700
53.8%
19
2.9%
NB
685
43.1%
665
41.8%
-20
-3.0%
SB
811
51.0%
838
52.7%
27
3.3%
EB
642
49.4%
759
58.4%
117
18.2%
WB
731
45.1%
793
48.9%
62
8.4%
EB
712
62.5%
830
72.8%
118
16.5%
WB
668
58.6%
726
63.7%
58
8.6%
NB
618
68.7%
662
73.6%
44
7.1%
SB
494
54.8%
526
58.5%
33
6.6%
NB
595
52.2%
606
53.1%
11
1.8%
SB
637
48.3%
667
50.6%
30
4.7%
EB
603
45.6%
614
46.5%
11
1.8%
WB
595
45.1%
604
45.8%
9
1.5%
NB
1013
73.2%
1084
78.3%
70
7.0%
SB
1028
74.2%
1119
80.8%
92
8.9%
NB
802
61.7%
748
57.6%
-54
-6.7%
SB
889
68.4%
973
74.9%
85
9.5%
NB
805
61.9%
886
68.2%
81
10.1%
SB
914
70.3%
985
75.8%
71
7.8%
12.5.25 It can be seen in Table 12.13 above that by the proposed opening year of 2015 all links on
the local road network will operate within their capacity during the Saturday Peak. The
highest RFC includes the A4146 Leighton Buzzard Road (SB) south of the Combe Street
Junction which will increase to 80.8% in the future scenario and will therefore be
approaching capacity, although not to detrimental levels.
12.5.26 The table also compares the RFC from the recorded baseline to give a measure of the
impact the development will have on the surrounding links during the proposed opening
year. The largest percentage increase in link flow (18.2%) occurs on the Queensway link,
west of the Marlowes junction (EB).
12.5.27 For all the links assessed, the increase in flows is below the 30% ‘flow increase threshold of
concern’ for links not classified as sensitive set out in the Institute of Environmental
Assessment guidance. Therefore, it can be concluded that the increase in traffic due to the
development is not a significant environmental issue.
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Mitigation Measures
Construction phase mitigation measures
12.6.1
A number of measures are possible to mitigate against the negative traffic impacts of the
construction of the development. A program of wheel washing will be implemented as
vehicles exit the site. Wheel washing prevents dust and debris being transported out of the
site and deposited on the surrounding roads, which causes environmental problems and
road safety issues.
12.6.2
Implementation of the CTMP will help manage the traffic entering and exiting the site during
construction to reduce the impact on the road network. The CTMP will ensure that control
measures, as listed below, are implemented on the site.
12.6.3
All materials removed from the site will be dampened and covered by tarpaulin, to prevent
spillage onto the surrounding roads.
12.6.4
Where possible, all equipment and machinery will be stored on site to minimise traffic
transporting equipment to and from the site. All large plant traffic will only be allowed with the
permission of the project manager who will take all necessary care to co-ordinate the arrival
with other vehicle movements and lessen the impact on the surrounding area.
12.6.5
Construction traffic routing avoiding sensitive areas will be implemented. At present, it is
unsure where materials will be sourced from. However it should be possible to limit
construction traffic to the strategic road network.
12.6.6
The proposed development strives for sustainability wherever possible. In relation to
construction, where possible, materials will be reused, and in particular excavated soils will
be used for re-grading. Waste will be minimised through the selection of material`s, suppliers
and construction processes, and where possible, local labour will be employed. These
objectives and the means to achieve them will become part of the construction contracts,
and therefore compliance will be measurable and enforceable. Each of these features of
sustainable construction will reduce the impact of construction traffic. It is fully expected that
the appointed contractor will prepare a Construction Traffic Management Plan that will
present details of these issues and how they will be dealt with.
Operational phase mitigation measures.
12.6.7
The access strategy for the proposed food store recognises the importance of encouraging
walking and cycling within, and also to and from the development. The development’s
accessible location immediately adjacent to the bus services on Queensway and Marlowes
will help in encouraging public transport use. It is also within reasonable walking and cycling
distance of the shopping parade on Marlowes.
12.6.8
Implementation of travel plans and personalised journey planning at the site will help
promote the use of more sustainable travel, encouraging people to consider alternatives to
using their cars. This will help reduce traffic on the network.
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12.6.9
A number of improvements are proposed which will have beneficial effects on the
accessibility of the site and the local area as a whole. These include pedestrian and cycle
routes through and around the site, including the riverside walk. These are fully detailed in
the Transport Assessment submitted in support of the proposed development.
Residual Effects
Construction phase
12.7.1
It will be apparent that a construction project is underway. However, mitigation will be put in
place to help minimise the impact on the local community. The site will be accessed from the
A4146. Therefore construction traffic will be primarily kept to the strategic road network, and
will not impact on the local streets in Hemel Hempstead. It is expected that construction
workers will access the site by car and bus, on foot and by bicycle. For those that drive, a
compound within the site will be made available to ensure no off-site parking is required.
12.7.2
The mitigation measures available will ensure that minimal impact is experienced at any one
time during the construction phase, although the magnitude of the effect is likely to remain as
described. Importantly, however, the measures described will contribute to reducing the
perception of disruption for surrounding residents. It is considered that the construction
phase will have only a minor adverse impact.
Outline of residual effects from the completed development
12.7.3
Once complete the impact on the highway network of the proposed development will be
minimal. In the instances where highway junctions would be put under stress, mitigation
measures are proposed; details of these are within the Transport Assessment for ‘The Link’
development. The main impact of the development will be on the strategic road network, but
will be absorbed within the background traffic, with negligible impacts.
12.7.4
In the medium to longer term, the traffic associated with the proposed development will be
non-consequential on the highway network as the Town Centre Masterplan and associated
infrastructure is realised. The impact of the development on the highway links referred to
within this chapter have all been below the 30%. As such, and in accordance with the
Guidelines for the Environmental Assessment of Road traffic, the impact of the development
in traffic terms can be termed negligible.
12.7.5
A number of improvements for pedestrian and cycle links are proposed as part of the
development. These will help formalise the routes through and around the site providing
both east west and north south links. As such, it is expected that the proposed development
will have minor beneficial impacts on pedestrian and cycle connectivity.
Summary
12.8.1
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The assessment of the environmental impact of transport has been undertaken based on
best practice and guidance. The impact of the proposed development has been assessed in
relation to the effect on the local highway network and local accessibility and sustainability
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issues. A baseline situation of 2015 has been established and the added impact of the
proposed development has been assessed in relation to this baseline.
12.8.2
The impact of traffic associated with the proposed development can also be accommodated
on the various links considered. It is considered that together, the package of transport
measures would ensure the development has good accessibility by all transport modes,
gives significant improvements to walking and cycling networks, and reduces traffic on local
residential streets. The residual highway impacts, with the proposed new infrastructure in
place, go beyond mitigating the effects of the development and in general highway impacts
are negligible.
12.8.3
The impact of the development on accessibility and the encouragement of non-car modes is
considered to be positive. The local pedestrian and cycling environment is considered to be
improved, not least due to the connections to be provided through the site. With regard to
accessibility and sustainable travel, the development provides further improvements to a
highly accessible area. The effects are classed as minor beneficial.
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13
Noise & Vibration
Introduction
13.1.1
This chapter presents the results of the noise & vibration assessment of the proposed
development and has been prepared by Peter Brett Associates LLP. It addresses the
baseline noise climate and the suitability of the site for the proposed development.
13.1.2
The chapter also describes the potential impacts arising from the proposed development
during the construction and operational phases. Mitigation measures are outlined to reduce
these impacts. An assessment of the significance of the residual effects, following mitigation,
is provided.
13.1.3
No significant existing sources of vibration have been identified in the vicinity of the site, and
there are no significant sources of vibration associated with the operational phase of the
proposed development. Therefore, the only sources of vibration considered in this chapter
are those associated with the construction activities.
13.1.4
A description of the technical terminology used in this chapter is provided in Appendix H.1.
Policy Context
The National Planning Policy Framework (NPPF)
13.2.1
The National Planning Policy Framework was published in March 2012.In respect of noise,
the document states that:
“The planning system should contribute to and enhance the natural and local environment by
…preventing both new and existing development from contributing to or being put at
unacceptable risk from, or being adversely affected by unacceptable levels of … noise
pollution”.
13.2.2
It goes on to advise that
“Planning policies and decisions should aim to:
 Avoid noise from giving rise to significant adverse impacts on health and quality of life
as a result of new development;
 Mitigate and reduce to a minimum other adverse impacts on health and quality of life
arising from noise from new development, including through the use of conditions;
 Recognise that development will often create some noise and existing businesses
wanting to develop in continuance of their business should not have unreasonable
restrictions put on them because of changes in nearby land uses since they were
established; and
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 Identify and protect areas of tranquillity which have remained relatively undisturbed by
noise and are prized for their recreational and amenity value for this reason.”
13.2.3
The NPPF indicates that the Noise Policy Statement for England (NPSE) should be used to
define “significant adverse impacts”. A summary of the NPSE is provided below, and it is
understood that the UK government is currently undertaking research to quantify the
significant observed adverse effect levels for noise
Noise Policy Statement for England
13.2.4
The Noise Statement for England was published in March 2010. The document seeks to
clarify the underlying principles and aims in existing policy documents, legislation and
guidance that relate to noise. It also sets out the long term vision of Government noise
policy: “to promote good health and a good quality of life through the effective management
of noise within the context of Government policy on sustainable development”.
13.2.5
The NPSE clarifies that noise should not be considered in isolation of the wider benefits of a
scheme or development, and that the intention is to minimise noise and noise effects as far
as is reasonably practicable having regard to the underlying principles of sustainable
development.
Local Policy
13.2.6
Dacorum Borough Council submitted a Core Strategy in June 2012 but this has not been
currently adopted. Until this is formally adopted DBC refers to The East of England Plan
along with saved polices from the Dacorum Borough Local Plan 1991-2011.
13.2.7
Policy ENV7 – Quality in the Built Environment of the East of England Plan states that:
“New development should… reduce pollution, including emissions, noise and light pollution.”
Noise Guidance
British Standard 8233: 1999 Sound Insulation and Noise Reduction for Buildings –
Code of Practice
13.2.8
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BS 8233:1999 sets out the recommended indoor noise levels in habitable rooms for
dwellings such as living rooms and bedrooms, when they are unoccupied. These
recommended levels are presented in Table 13.1
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Table 13.1: Recommended Internal Ambient Levels
Design Range LAeq.T dB
Criterion
Typical Situation
Good
Reasonable
Reasonable
resting/sleeping conditions
Living rooms
30
40
Bedrooms1
30
35
1
For a reasonable standard in bedrooms at night, individual noise events (measured with F timeweighting) should not normally exceed 45 dB L Amax.
British Standard 5228: 2009 Code of Practice for Noise and Vibration Control on
Construction and Open Sites
13.2.9
BS 5228:2009 ‘Code of Practice for Noise and Vibration Control on Construction and Open
Sites’ (British Standards Institution, 2009) gives recommendations for basic methods of
noise and vibration control relating to construction and open sites where work
activities/operations generate significant noise and/or vibration levels
Control of Pollution Act 1974: Implementation of part III – Noise
13.2.10 Control of Pollution Act 1974 (Department of the Environment, 1974) under Noise from
Construction and Demolition Sites, Section 60 gives local authorities the power to serve a
notice imposing requirements as to the way which construction works are to be carried out.
Section 61 gives a person who intends to carry out works the opportunity to determine the
local authority’s requirements by seeking their consent for the proposed methods of works
and mitigation measures.
British Standard 4142: 1997 Method for Rating Industrial Noise Affecting Mixed
Residential and Industrial Sites
13.2.11 This method is applied to industrial sites but can also be applied to commercial development
where fixed plant is to be installed. Dacorum Borough Council has requested this method be
used for assessing plant noise.
13.2.12 BS 4142 (British Standards Institution, 1997) sets out methods for determining, at the
outside of a residential building:

Noise levels from factories, industrial premises, fixed installation of sources of an
industrial nature in commercial properties;

Background noise level (background noise levels below 30 dB are considered to be ‘very
low’) and;

Assessing whether the noise referred to above is likely to give rise to complaints from
people residing in the building considered.
13.2.13 The method subtracts the background noise level LA90,T (that which is exceeded for 90% of a
given duration) from the ‘rating level’, LArTr, which is calculated by adjusting the noise source
for a character correction, if required. Table 13.2 shows the assessment levels and advice.
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Table 13.2: BS4142 Assessment Levels
LAr,Tr – LA90,T (dB)
Advice
+ 10
Complaints likely
+5
Marginal significance
- 10
Complaints unlikely
Calculation of Road Traffic Noise (CRTN): 1988
13.2.14 CRTN is a Department of Transport (DoT) memorandum that describes the procedure to
calculate the road traffic noise at a given receptor location.
13.2.15 Section III (The Measurement Method) described the shortened measurement procedure to
be undertaken within 3 consecutive hours between 10:00 and 17:00 hrs. A formula is
presented to calculate the noise level dB LA10,18h based on that measurement.
Method for Converting the UK Road Traffic Noise Index LA10,18h to the EU Noise Indices
for Road Noise Mapping: 2006
13.2.16 This report was prepared by the Transport Research Laboratory (TRL) and Casella Stanger
on behalf of the Department for Environment, Food and Rural Affairs (Defra) in January
2006.
13.2.17 It presents a methodology to convert the noise index for traffic noise derived from CRTN,
LA10,18h, into the noise indicators required by the Environmental Noise Directive (EU Noise
Indices) Lden and Lnight. For road traffic noise, supplementary noise indicators are also
presented LAeq,12h (07:00-19:00), known as Lday, LAeq,4h (19:00-23:00), known as Levening and
LAeq,16h (07:00-23:00). This methodology has been used in the noise model.
Building Bulletin 93 (BB93): Acoustic Design of Schools – A Design Guide
13.2.18 BB93 is a Department for Education and Skills design guide that provides a regulatory
framework for the acoustic design of schools in support of the Building Regulations. It gives
recommendations for the planning and the design of schools.
13.2.19 This document includes the specification of acoustic performance to provide a good
minimum standard for school design.
World Health Organisation – Guidelines for Community Noise: 1999
13.2.20 This document is a review of the medical and scientific knowledge on health impacts of
community noise, and provides guidance to health authorities and professional dealing with
the effect of noise.
13.2.21 It presents in Table 1 the guideline values for community noise in specific environments. In
dwellings, the effect of noise is typically sleep disturbance, annoyance and speech
interference.
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13.2.22 It also provides guidance for instantaneous maximum noise levels. At night inside bedrooms
the LAmax noise level should not exceed 45dB(A) which equates to an L Amax of 60dB(A)
outside the bedroom based on an open window situation.
Methodology
Consultation with Dacorum Borough Council
13.3.1
Consultation has been undertaken with the Environmental Health Department at Dacorum
Borough Council (DBC) between 27th September 2012 and 8th January 2013 to agree the
methodology.
13.3.2
Appendix H.2 presents the correspondence with DBC. The following bullet points
summarise the key issues covered:
13.3.3

A baseline noise survey will be undertaken to determine the existing noise condition of
the site. Short-term noise readings will be taken at locations representative of the
existing dwellings surrounding the site on Queensway, Leighton Buzzard Road and
Marlowes. A 24-hour unattended noise reading will be undertaken within the site;

The construction noise & vibration impact will be assessed qualitatively in accordance
with BS5228:2009. Outline mitigation measures will be provided;

A noise model will be prepared and validated against the noise survey results;

Noise arising from any commercial or industrial elements of the proposed development
will be assessed in accordance with BS4142. Plant shall comply with the rating level
equal to background; and

The change in noise levels due to generation of post construction development traffic
including car park use and deliveries upon nearby sensitive receptors will be studied
against assessment criteria developed to determine the magnitude and significance of
the assessment.
In the consultation response DBC also requested noise levels are assessed for
instantaneous noise events. Therefore, maximum noise levels from deliveries and car park
noise have been assessed to ensure LAMax noise levels inside bedrooms are not exceeded
during the night.
Baseline Data Collection
13.3.4
A baseline noise survey was undertaken between 27th and 28th September 2012.
13.3.5
The purpose of the survey was to establish the existing noise climate at the site and
surrounding areas. Furthermore, the survey results are used to validate the preparation of
the computer noise model, so that impacts associated with the development can be
assessed and reported upon.
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13.3.6
Table 13.3 describes the noise survey locations and states what the existing dominant noise
sources are. The location of the noise surveys are presented in Figure 13.1 of Appendix
H.3.
Table 13.3: Baseline Noise Survey Locations
Location
Description
Dominant Source
1
On site at the north west boundary
Road traffic
2
Existing dwellings at the
Queensway/Marlowes Road Roundabout
Road traffic
3
At existing dwellings east of the site along
Road traffic
Marlowes Road
4
At existing dwellings west of the site along
Road traffic
Leighton Buzzard Road
5
At existing dwellings south-west of the
site along Leighton Buzzard Road
Road traffic
13.3.7
Unattended noise readings were taken at Location 1 over a 24 hour period.
13.3.8
Short-term attended readings were taken at Locations 2 and 5 (two series of 1 hour)
between 10:00 and 17:00 hrs during daytime. At Locations 3 and 4 three-hour continuous
attended measurements were taken in line with the shortened CRTN methodology.
13.3.9
The noise parameters measured during the survey were dB LAeq, dB LA10, dB LA90 and dB
LAmax. Audio recordings were also made. In the summary tables of the results, the lowest
measured dB LA90 is presented to set the fixed plant noise limits.
13.3.10 The weather conditions were considered to be suitable for a noise survey to be undertaken,
as it remained dry during the measurements and the wind speed did not exceed 2m/s.
Instrumentation
13.3.11 Three type 1 sound level meters were used for the survey. Each was mounted at 1.5m
above the ground and at a minimum of 3m away from any reflective surface.
13.3.12 The noise instrumentation has valid laboratory certification, which is available upon request.
Field calibrations were performed before and after the measurements with no significant
fluctuation recorded. The instrumentation used in the noise monitoring is listed in Table
13.4.
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Table 13.4: Equipment Table
Item
Type
Manufacturer
Serial
Number
Laboratory
Calibration
Date
Sound
Calibrator
4231
Bruel & Kjær
2619372
20.01.2012
Sound
Calibrator
4231
Bruel & Kjær
2619373
20.01.2012
Sound
Calibrator
4231
Bruel & Kjær
2619374
20.01.2012
Hand-Held
Analyzer
2250
Bruel & Kjær
2626230
20.01.2012
Hand-Held
Analyzer
2250
Bruel & Kjær
2626231
20.01.2012
Hand-Held
Analyzer
2250
Bruel & Kjær
2626233
23.01.2012
4189
Bruel & Kjær
2621208
20.01.2012
4189
Bruel & Kjær
2621209
20.01.2012
4189
Bruel & Kjær
2621212
20.01.2012
Prepolarized
free-field ½ “
microphone
Prepolarized
free-field ½ “
Microphone
Prepolarized
free-field ½ “
Microphone
Assessment
Construction Noise and Vibration
13.3.13 Noise and vibration generated during the construction phase of the development have been
assessed qualitatively in accordance with advice provided on using the best practicable
means as stated in BS 5228:2009 Parts 1 and 2 to minimise the noise and vibration impact
of construction activities on nearby receptors. These are considered in more detail in the
mitigation section of this chapter. A quantitative assessment will be carried out preconstruction when more details of equipment and phasing are available.
13.3.14 Although Annex E of BS 5228-1:2009 is an Informative document, and as such is not
afforded the same level of authority as the British Standard itself, it provides useful guidance
on the significance of noise effects and examples of noise limits for construction noise based
on the pre-existing noise climate (i.e. the pre-construction baseline). Day, evening and
night-time periods are defined, with limits provided as shown in Table 13.5
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Table 13.5: BS 5228 Recommended Construction Noise Limits
Assessment category and
threshold value period
Threshold value, in decibels (LAeq T) (dB)
Category A A)
Category B B)
Category C C)
Night-time (23.00−07.00)
45
50
55
55
60
65
65
70
75
Evenings and weekends
D)
Daytime (07.00−19.00) and
Saturdays (07.00−13.00)
NOTE 1 A significant effect has been deemed to occur if the total L Aeq noise level, including
construction, exceeds the threshold level for the Category appropriate to the ambient noise level.
NOTE 2 If the ambient noise level exceeds the threshold values given in the table (i.e. the ambient
noise level is higher than the above values), then a significant effect is deemed to occur if the total
LAeq noise level for the period increases by more than 3 dB due to construction activity.
NOTE 3 Applied to residential receptors only.
A) Category A: threshold values to use when ambient noise levels (when rounded to the nearest 5
dB) are less than these values.
B) Category B: threshold values to use when ambient noise levels (when rounded to the nearest 5
dB) are the same as category A values.
C) Category C: threshold values to use when ambient noise levels (when rounded to the nearest 5
dB) are higher than category A values.
D) 19.00–23.00 weekdays, 13.00–23.00 Saturdays and 07.00–23.00 Sundays.
13.3.15 Nearby noise-sensitive receptors have been considered for impact from construction noise.
These include the following:
13.3.16

Existing dwellings at the Queensway/Marlowes Road Roundabout;

At existing dwellings east of the site along Marlowes Road;

At existing dwellings west of the site along Leighton Buzzard Road;

At existing dwellings south-west of the site along Leighton Buzzard Road.
The survey data has been used to determine the thresholds in Table 13.5.
Operational Noise Model
13.3.17 A noise model has been prepared using the computer software SoundPLAN version 7.1.
13.3.18 The road traffic noise was predicted following guidance in the Calculation of Road Traffic
Noise (CRTN). The ‘Method for Converting the UK Road Traffic Noise Index L A10,18h to the
EU Noise Indices for Road Noise Mapping: 2006’ was used to convert the predicted noise
levels to the daytime and night described in BS8233
13.3.19 The following road traffic scenarios have been modelled.
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
Baseline Year 2011;

Future Year 2015 – without proposed development; and;

Future Year 2015 – with proposed development.
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13.3.20 The baseline situation was used to validate the model against the survey data. The future
scenarios were modelled to determine the difference between the with development scenario
with maximum traffic flows against the future scenario if no development were to occur
13.3.21 The road traffic data incorporated into the model is presented in Appendix H.4. The road
traffic noise model has been validated against the noise survey results. Details of the
validation are presented in Appendix H.4.
13.3.22 The masterplan has been incorporated into the noise model having regard to the floor plan
drawings prepared by DLA Architecture, dated April 2013.
Change in Ambient Noise Levels
13.3.23 Change in ambient noise levels at existing noise-sensitive dwellings due to the operation of
the proposed development has been determined in accordance with the significance criteria
defined later in this chapter.
13.3.24 The 2015 ‘with development’ scenario has been compared with the 2015 ‘without
development’ scenario. The future with development scenario includes development traffic
on the local roads. It also includes noise associated with the foodstore car park and heavy
vehicle deliveries.
13.3.25 Based on similar foodstores it has been assumed that there will be five heavy vehicle
deliveries per day to the foodstore. The noise associated with the deliveries has been
included within the noise model scenario future year 2015. Noise due to the heavy vehicle
reversing and manoeuvring has been assessed. The assumptions on the noise sources are
presented in Appendix H.5 A further assessment for night-time maximum noise levels has
also been undertaken for deliveries and is described in section 13.3.7.
College Assessment
13.3.26 Mitigation to meet the internal noise levels for the college has also been assessed. The
majority of the uses for the college are for workshops which would generate their own noise
and would not be considered to be sensitive.
13.3.27 However, on the mezzanine level, first floor and second floor there will be classrooms which
are considered to be noise sensitive. Therefore, mitigation for facades of these teaching
spaces has been specified.
13.3.28 For classrooms, tutorial and laboratories the internal noise levels should meet 35 dB(A).
There is also a learning resource centre on the first floor plan and BB93 states that resource
areas should meet an internal noise levels of 40dB(A)
13.3.29 There will also be an outline application for part of the college on the north-west section of
the site. At this stage no details are available on the internal layout and therefore this would
need to be assessed at detail design stage when the uses for the rooms are known.
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Noise from Commercial Use and Fixed Plant
13.3.30 The proposed development will include a foodstore. As there will be fixed plant associated
with the foodstore in the form of refrigerated condensers and extract fans an assessment
has been undertaken in accordance with BS 4142. The majority of the plant will be roof
mounted.
13.3.31 As finalised details of fixed plant are not available, preliminary data provided by Belair
Research Limited has been assessed and described in Appendix H.5. The assessment
shows that noise due to fixed plant would not exceed background noise levels at nearby
receptors.
13.3.32 In addition Noise limits, rating level LArTr, are recommended at the nearest proposed and
existing noise sensitive receptors having regards to the background noise levels measured
in the baseline noise survey. The limits are defined at 1 metre from the façade of the
receptors.
13.3.33 The noise limits allow for character corrections, where necessary Character corrections are
applied if the noise is irregular enough to attract attention or contains a distinguishable,
discrete, continuous note or contains distinct impulses.
Night-time Noise - LAmax Noise Levels
13.3.34 In addition to the change in ambient noise levels an assessment has also been made of
LAmax noise levels. This has been calculated by incorporating an instantaneous, non-time
corrected noise level from a short term event of a car door slamming in the car park at the
nearest dwellings. This has been undertaken to ensure that LAmax noise level criteria within
WHO guidelines of 60 dB outside bedrooms at night is not exceeded.
13.3.35 Early morning deliveries could also occur and therefore an LAmax noise level for this event
has also been assessed during the night. Noise consultants Belair Reseach Limited have
undertaken noise measurements for maximum noise levels associated with deliveries
manoeuvring within, entering, or leaving the service yard. The maximum noise from
deliveries is 75dB(A) at 10m. This noise level has been assessed for night-time disturbance
at nearby dwellings.
Significance Criteria
13.3.36 The significance of residual effects has been assessed in accordance with the generic
significance criteria provided in Chapter 5. Tables 13.6 - 13.7 define the sensitivity of the
receptor and the magnitude of the effect which together determine the level of significance.
Table 13.6: Sensitivity of Receptors
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Sensitivity
Description
High
Dwellings
Medium
Schools/Educational Use, hospitals, quiet recreation areas
Low
Offices, cafes/bars with external areas, industrial, retail
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13.3.37 When considering noise changes from a road traffic source, a comparison is made between
the ‘with development’ and ‘without development’ scenarios. These changes can potentially
increase or decrease noise levels.
13.3.38 When considering the significance of internal or external noise levels for a specific proposed
use (such as internal noise levels for dwellings, or construction noise) a comparison is made
between the predicted noise levels and the relevant guideline or policy level.
13.3.39 A change of 3 dB is generally considered the minimum perceptible under normal (as
opposed to ‘test’ or ‘laboratory’) conditions, and a change of 10 dB corresponds roughly to
halving or doubling the loudness of sound as perceived by the human ear.
Table 13.7: Table of Magnitude
Magnitude
dB change compared with
baseline or difference in predicted
level compared to guideline level
Description
Negligible
<3 dB
Not perceptible to human ear, within
margins of error of measurement.
Small
3 - 5.9 dB
Perceptible but less than a
doubling/halving of sound energy.
Medium
6 - 9.9 dB
Up to a doubling/halving of loudness.
Large
>10 dB
Over a doubling of loudness.
13.3.40 Table 13.8 sets out how the sensitivity of the receptors and the magnitude of the impact
have been combined to determine the significance criteria. The criteria range from not
significant to severe.
Table 13.8: Significance Criteria
Magnitude
Sensitivity
Non
Sensitive
Low
Medium
High
Negligible
Not
significant
Not
significant
Not
significant
Not
significant
Small
Not
significant
Not
significant
Minor
Moderate
Medium
Not
significant
Minor
Moderate
Major
Large
Minor
Moderate
Major
Severe
13.3.41 An increase in noise level is described as adverse and a decrease in noise level as
beneficial.
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Baseline Conditions
13.4.1
The noise climate on site and surroundings was observed to be dominated by the local road
traffic network.
13.4.2
Tables 13.9 – 13.11 present a summary of the noise survey results. A detailed version of the
survey data is provided in Appendix H.6.
Table 13.9: Summary Table of Long Term Measurements
Location
Period
LAeq,T dB
LA90,T dB
LA10,T dB
LAFmax,T
dB
Daytime
Duration
(h.m.s)
16:45:13
1
1
62
51
62
-
Night-time
8:00:00
54
42
55
85
Table 13.10: Summary Table of Daytime Short Term Measurements
Location
Duration
LA90,T
dB
58
LA10,T dB
02:00:00
LAeq,T
dB
65
2
3
03:00:00
65
55
67
4
03:00:00
70
59
73
5
02:00:00
65
58
67
66
Table 13.11: Summary Table of Night-time Short Term Measurements
Location
Duration
LA90,T
dB
38
LA10,T dB
00:45:00
LAeq,T
dB
55
57
LAFmax,T
dB
76
2
3
00:45:00
59
36
59
78
4
00:45:00
61
36
58
83
5
00:45:00
52
36
55
71
13.4.3
The measurement results above have been used to validate the noise model.
13.4.4
The background noise levels dB LA90 presented in the tables above have been used to
derive the proposed noise limits for the fixed plant from the development.
Potential Effects
Construction Noise and Vibration
13.5.1
Construction noise could potentially increase the ambient noise levels at existing noisesensitive receptors and proposed noise-sensitive receptors that are inhabited whilst
construction continues.
13.5.2
BS 5228:2009 Annex E (Informative) states that noise predictions should be undertaken to
determine eligibility for noise insulation or temporary re-housing. However, the informative
also states that these assessments should be undertaken when a contractor has been
appointed and detailed method statements on the construction programme and plant to be
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used are available. Therefore, a quantitative assessment of the construction phase should
be completed when such information is available.
13.5.3
The noise survey has been used to determine the free field baseline noise levels LAeq,T at
the nearest noise sensitive receptors potentially affected by construction noise.
13.5.4
Table 13.12 provides the construction noise categories in accordance with the threshold
values presented in Table 13.5.
Table 13.12: Baseline Noise Level at Construction Noise Sensitive Receptor – Daytime
Location
LAeq,T dB
BS5228 Category
Existing dwellings at the
Queensway/Marlowes Road
Roundabout
65
B
At existing dwellings east of the
site along Marlowes Road
65
B
At existing dwellings west of the
site along Leighton Buzzard
Road
70
C
At existing dwellings south-west
of the site along Leighton
Buzzard Road
65
B
13.5.5
Current noise levels at existing dwellings provide high threshold values (in categories B and
C) and therefore the impact from construction activities would not likely to be significant and
standard good practice measures would be considered to mitigate construction noise.
13.5.6
Vibration transmitted from construction activities through the ground to the receiver cannot
be reliably calculated. Many factors such as rock/soil type, water content, solid damping,
etc., greatly influence the way in which vibration travels through the ground. Therefore,
monitoring of vibration levels as a result of construction / demolition is recommended to be
considered in the Construction Environmental Action Plan (CEAP) for each phase for periods
when piling is necessary.
Operational Noise
College
13.5.7
The college has also been assessed within the noise model. The daytime noise levels have
been assessed for the future year 2015.
13.5.8
Table 13.13 presents the predicted free field noise levels generated by the model at
locations representative of the facades of the college development.
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Table 13.13: Predicted noise levels at the façade of the College – Daytime
13.5.9
Façade Location
Sensitive Room
Daytime Noise
Level LAeq,16hr (dB)
North Façade facing
Queensway
Classroom and
resource centre
61
East Façade facing
Marlowes
Classroom and
resource centre
63
South Façade facing
foodstore
Classroom
48
West façade facing Leighton
Classroom
Buzzard Road
56
The modelling results presented in Table 13.13 have been used to determine the mitigation
(i.e. glazing) at the facades of the different room types.
13.5.10 Without appropriate glazing applied the internal noise levels would be exceeded and the
significance would be a moderate impact based on the medium sensitivity of the receptor.
Commercial and Fixed Plant Noise
13.5.11 Noise from plant associated with the foodstore and petrol filling station, including any
corrections for acoustic characteristics, should be equal to the existing background noise
levels.
13.5.12 The limits should apply to the cumulative noise from all fixed plant items and should include
any corrections for acoustic characteristics. Limits have been derived for both the daytime
and night-time periods.
13.5.13 The proposed noise limits, rating level LArTr, presented in Table 13.15 are based on the
measured background noise levels at Location 3 and 5 which are the closest receptors to the
foodstore.
Table 13.15: Proposed Fixed Plant Noise Limits
Source
Receptor Location
Period
Proposed Noise Limit Db
Fixed plant associated
with the foodstore and
filling station
Existing Dwellings
Daytime
along Marlowes east of
site
Night-time
55
Fixed plant associated
with the foodstore and
filling station
Existing Dwellings
south west of site
Daytime
58
Night-time
36
36
13.5.14 The proposed limits in Tables 13.14 – 13.15 are defined at 1 metre from the façade of the
receptors shown. These limits would meet the DBC noise criteria for fixed plant and would
be between the marginal significance and complaints unlikely scenario as defined within BS
4142.
13.5.15 By meeting these limits the impact at nearby dwellings would be negligible.
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Change in Ambient Noise Levels
13.5.16 The potential transportation noise impact arising from the operation of the development upon
the nearby existing sensitive areas has been determined using the SoundPLAN noise model.
13.5.17 Figures 13.2 and 13.3 in Appendix H.3 shows the change in noise levels during the
daytime and night-time respectively as a result of the comparison between the modelling
scenarios for a future year with development against without development
13.5.18 It can be seen from the figures that the additional road traffic flows, car park noise and
deliveries introduced by the proposed development would result in an increase of noise
levels of less than 3dB at existing dwellings, for the daytime and night-time periods.
Referring to the impact matrix presented in Table 13.8, this magnitude is classified as a
negligible impact.
LAmax Noise Levels
13.5.19 Table 13.16 provides the LAmax noise level calculated at the nearest dwellings from car park
noise.
Table 13.16: LAMax Assessment for noise from car park at nearby dwellings
Location
LAMax Noise Level Outside Dwelling
(dB)
At existing dwellings west of the site
44
along Leighton Buzzard Road
At existing dwellings south-west of
the site along Leighton Buzzard
Road
47
13.5.20 Table 13.17 provides the LAmax noise level calculated at the nearest dwellings from delivery
noise during the night.
Table 13.16: LAMax Assessment for noise from superstore deliveries at nearby dwellings
Location
LAMax Noise Level Outside Dwelling
(dB)
At existing dwellings west of the site
52
along Leighton Buzzard Road
At existing dwellings south-west of
the site along Leighton Buzzard
Road
46
13.5.21 As can be seen in Table 13.16 the LAmax noise levels outside the receptors would not exceed
60 dB(A) and be within the guidance limits provided in WHO. Therefore, night-time activity
associated with deliveries and car park noise would not be significant.
13.5.22 As the criteria will be met this would be a negligible impact at existing dwellings.
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Mitigation Measures
Construction Noise and Vibration
13.6.1
Further assessment of construction noise mitigation should be undertaken when a principal
contractor has been appointed and detailed method statements, the construction programme
and descriptions of the proposed plant are available.
13.6.2
The following advice is based on the guidance provided in BS 5228 and should be applied to
minimise the noise breakout from the construction activities affecting noise sensitive
receptors:
13.6.3

Ensuring the use of quiet working methods, the most suitable plant and reasonable
hours of working for noisy operations, where reasonably practicable;

Locating noisy plant and equipment as far away from dwellings as reasonably possible,
and where practical, carry out loading and unloading in these areas;

Screening plant to reduce noise which cannot be reduced by increasing the distance
between the source and the receiver (i.e. by installing noisy plant and equipment behind
large site buildings);

Shutting down any machines that work intermittently or throttling them back to a
minimum;

Orientating plant that is known to emit noise strongly in one direction so that the noise is
directed away from houses, where possible;

Closing acoustic covers to engines when they are in use or idling; and

Lowering materials slowly, whenever practicable, and not dropping them.
The main source of vibration typically associated with the construction process is piling.
Methods of piling to minimise the effects of vibration on receptors should be considered,
depending on the ground conditions to be encountered.
Operational Noise
College
13.6.4
A mitigation strategy for the college has been outlined to indicate the likely building elements
required to meet the guidance noise levels contained within BB93.
13.6.5
Mitigation measures are indicated in Tables 13.18 for the different rooms on the facades of
proposed college development.
13.6.6
Table 13.18 presents the Weighted Sound Reduction Index (Rw) dB for glazing units.
Examples of double glazing units are also provided
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Table 13.18: College Façade Mitigation
Façade Location
North Façade facing
Queensway
East Façade facing
Marlowes
South Façade facing
foodstore
Sensitive Room
Glazing Rw to meet
Internal Noise
Levels (dB)
Example of Double
Glazed Unit (glass
width mm / air gap
width mm / glass
width mm
Classroom
31
4/12/4
Resource Centre
31
4/12/4
Classroom and
resource centre
31
4/12/4
Resource Centre
31
4/12/4
31
4/12/4
31
4/12/4
Classroom
West façade facing Leighton
Classroom
Buzzard Road
13.6.7
The internal noise levels would not be met with an open window. Therefore, alternative
ventilation will be required. This could be either acoustically attenuated passive ventilation
units or mechanical vents.
Residual Effects
Construction Phase
13.7.1
Noise and vibration levels as a result of the construction works will be minimised by
implementing the mitigation methods advised in BS 5228:2009.
13.7.2
With mitigation, it is expected that the adverse effect of the construction phase of the
proposed development would be considered moderate and temporary at nearby dwellings.
Operational Phase
13.7.3
Mitigation measures have been recommended for the college to comply with the noise
guidance from BB93. These guidance levels would be met and the effect would be not
significant for teaching rooms.
13.7.4
Existing noise sensitive receptors would experience a not significant effect from noise arising
from development road traffic flows. In addition, fixed plant noise limits have been proposed
at the existing residential receptors in accordance with DBCs noise policy to ensure that this
effect is also not significant.
13.7.5
Noise from deliveries and car park noise during the night would also not be significant at
nearby dwellings.
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Summary
13.8.1
A noise and vibration assessment has been undertaken to determine the likely impacts from
and upon the proposed development.
13.8.2
Consultation was undertaken between 27th September 2012 and 8th January 2013 with the
Dacorum Borough Council (DBC) to agree the survey and assessment methodologies. The
assessment has been undertaken following the principles set in the National Planning Policy
Framework (NPFF).
13.8.3
A baseline noise survey was undertaken between 27th and 28th September 2012 to establish
the existing noise climate on site. The noise survey results have been used for validation of
the computer noise model.
13.8.4
A qualitative assessment has been undertaken for the likely noise & vibration impact
associated with the construction phase of the proposed development. Noise limits for the
construction activities have been proposed at the nearest existing receptors in accordance
with British Standard 5288: 2009 Code of Practice for Noise and Vibration Control on
Construction and Open Sites. Mitigation measures have been outlined based on best
practice measures presented in BS5288. It is considered that, with mitigation in place, the
residual effects are likely to be moderate and adverse.
13.8.5
A computer noise model has been prepared to assess the likely noise impact arising from
the operational phase of the development. The residual effect upon nearby existing dwellings
close to the site due to transportation noise associated with the proposed development is
considered to be not significant as the increase in noise level should not be perceptible to
the human ear.
13.8.6
The potential noise impact upon the college development has been assessed. Mitigations
measures have been outlined to meet the internal noise level criteria agreed contained within
BB93.
13.8.7
Noise limits at the nearest existing receptors for the fixed plant as part of the foodstore
development have been proposed. These are in accordance with DBC’s noise policy and
BS4142: 1997 Method for Rating Industrial Noise Affecting Mixed Residential and Industrial
Sites.
References
Document1

British Standards Institution, 1997. BS 4142:1997 Rating industrial noise affecting mixed
residential and industrial areas. London: BSI.

British Standards Institution, 2009. BS 5228-1:2009 Code of practice for noise and
vibration control on construction and open sites Part 1 Noise. London: BSI.

British Standards Institution, 2009. BS 5228-2:2009 Code of practice for noise and
vibration control on construction and open sites Part 2 Vibration. London: BSI.
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
British Standards Institution, 1999. BS 8233:1999 Sound insulation and noise reduction
for buildings – Code of Practice. London: BSI.

Department for Education and Skills, 2003, Building Bulletin 93 Acoustic Design of
Schools- A design guide, London TSO.
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14
Air Quality
Introduction
14.1.1
This chapter, prepared by Peter Brett Associates LLP, assesses the impacts of the proposed
development on local air quality. The chapter outlines the assessment methods used, the
current baseline conditions at the site and the surrounding area and the potential impacts
arising from the development during construction and operation. Proposed mitigation
measures necessary to offset impacts associated with the development are also described.
Scope
14.1.2
This assessment describes existing air quality within the study area and will assess the
likelihood of significant air quality impacts at sensitive locations. Impacts arising during
construction and operation of the development are assessed.
14.1.3
Construction phase impacts will be associated with dust deposition and spoiling of surfaces.
The main pollutants of concern related to construction activities are dust and particulate
matter (PM10).
14.1.4
Pollutants associated with the operational use of the development are nitrogen dioxide
(NO2), particulate matter (PM10 and PM2.5) and benzene. Road vehicles are the main source
for NO2 and particulate matter pollutants. Benzene emissions are associated with the
proposed petrol filling station.
14.1.5
The impact of odour from the proposed café within the foodstore is also considered.
Cooking activities have the potential to lead to the release of odours, which have the
potential to cause nuisance to local residents.
14.1.6
This assessment has been prepared taking into account all relevant national and local
guidance and regulations.
Policy Context
The Air Quality Strategy
14.2.1
The Air Quality Strategy (2007) establishes the policy framework for ambient air quality
management and assessment in the UK. The primary objective is to ensure that everyone
can enjoy a level of ambient air quality which poses no significant risk to health or quality of
life. The Strategy sets out the National Air Quality Objectives (NAQOs) and government
policy on achieving these objectives.
14.2.2
Part IV of the Environment Act 1995 introduced a system of Local Air Quality Management
(LAQM). This requires local authorities to regularly and systematically review and assess air
quality within their boundary, and appraise development and transport plans against these
assessments. The relevant NAQOs for LAQM are prescribed in the Air Quality (England)
Regulations 2000 and the Air Quality (Amendment) (England) Regulations 2002.
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14.2.3
Where an objective is unlikely to be met, the local authority must designate an Air Quality
Management Area (AQMA) and draw up an Air Quality Action Plan (AQAP) setting out the
measures it intends to introduce in pursuit of the objectives within its AQMA.
14.2.4
The Local Air Quality Management Technical Guidance 2009 (LAQM.TG(09)) 47 issued by
Defra for Local Authorities provides advice as to where the NAQOs apply. These include
outdoor locations where members of the public are likely to be regularly present for the
averaging period of the objective (which vary from 15 minutes to a year). Thus, for example,
annual mean objectives apply at the façades of residential properties, whilst the 24-hour
objective (for PM10) would also apply within garden areas. They do not apply to occupational,
indoor or in-vehicle exposure.
EU Limit Values
14.2.5
The Air Quality Standards Regulations 2010 implements the European Union’s Directive on
ambient air quality and cleaner air for Europe (2008/50/EC), and includes limit values for
NO2. These limit values are numerically the same as the NAQO values but differ in terms of
compliance dates, locations where they apply and the legal responsibility for ensuring that
they are complied with. The compliance date for the NO 2 EU Limit Value is 1 January 2010
which is five years later than the date for the NAQO.
14.2.6
Directive 2008/50/EC consolidated the previous framework directive on ambient air quality
assessment and management and its first three daughter directives. The limit values
remained unchanged, but it now allows Member States a time extension for compliance,
subject to European Commission (EC) approval.
14.2.7
The Directive limit values are applicable at all locations except:
14.2.8

Where members of the public do not have access and there is no fixed habitation;

On factory premises or at industrial installations to which all relevant provisions
concerning health and safety at work apply; and

On the carriageway of roads and on the central reservations of roads except where there
is normally pedestrian access.
The limit values are mandatory whereas there is no legal obligation to meet the NAQOs.
Therefore, the limit values carry more weight than the NAQOs.
Odour
14.2.9
There are currently no statutory standards or objectives in the UK covering the release and
subsequent impacts of odours. This is due to complexities involved with measuring and
assessing odours against compliance criteria, and the inherent subjective nature of odours.
14.2.10 It is recognised that odours have the potential to pose a nuisance for residents living near to
an offensive source of odour. Determination of whether or not an odour constitutes a
47
Defra, 2009, Local Air Quality Management Technical Guidance LAQM.TG(09).
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statutory nuisance in these cases is usually the responsibility of the local planning authority.
The Environmental Protection Act 1990 (Stationery Office, 1990) outlines that a local
authority can require measures to be taken where:
“Any dust, steam, smell or other effluvia arising on an industrial, trade and business
premises and being prejudicial to health or a nuisance…” or
“Fumes or gases are emitted from premises so as to be prejudicial to health or cause a
nuisance…”
14.2.11 Defra have released Guidance on the Control of Odour and Noise from Commercial Kitchen
Exhaust Systems (Defra, 2005). This guidance provides information on best practice
techniques for the minimisation of odour (and noise) nuisance from kitchen exhaust systems.
Planning Policy
National
14.2.12 The National Planning Policy Framework (NPPF) was published in March 2012. This sets
out the Government’s planning policies for England and how they are expected to be
applied. In relation to conserving and enhancing the natural environment, Paragraph 17
states that:
“Within the overarching roles that the planning system ought to play, a set of core landuse planning principles should underpin both plan-making and decision-taking. These
12 principles are that planning should…..contribute to conserving and enhancing the
natural environment and reducing pollution.”
14.2.13 Paragraph 109 states that:
“The planning system should contribute to and enhance the natural and local
environment by… preventing both new and existing development from contributing to or
being put at unacceptable risk from, or being adversely affected by unacceptable levels
of soil, air, water or noise pollution or land instability.”
14.2.14 Paragraph 124 states that:
“Planning policies should sustain compliance with and contribute towards EU limit
values or national objectives for pollutants, taking into account the presence of Air
Quality Management Areas and the cumulative impacts on air quality from individual
sites in local areas. Planning decisions should ensure that any new development in Air
Quality Management Areas is consistent with the local air quality action plan.”
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Local Policy
14.2.15 The Dacorum Borough Local Plan was adopted in 2004, and sets out the local development
policies for the borough. Policy 11: Quality of Development, states:
“Development will not be permitted unless:
(j) it avoids harm arising from pollution in all its forms, including air, water, noise and light
pollution. In particular there should be no detrimental effect on air quality in sensitive
areas (especially where traffic related air pollution problems arise)…”
14.2.16 Dacorum Borough Council (DBC) is currently preparing the Dacorum Core Strategy, which,
once adopted will set out the strategic vision, objectives and spatial strategy for the borough
for twenty years. The Core Strategy was formally submitted to the Planning Inspectorate in
June 2012. Policy CS32: Air, Soil and Water Quality states that:
“Development will be required to help:
a) support improvements in identified Air quality Management Areas and maintain air
quality standards throughout the area…
Any development proposals which would cause harm from a significant increase I pollution
(into the air, soil or any water body) by virtue of the emissions of fumes, particles, effluent,
radiation, smell, heat, light, noise or noxious substances, will not be permitted.”
14.2.17 The March 2013 on the post examination changes to the Core Strategy did not proposed any
changes to this policy.
Methodology
Baseline Conditions
14.3.1
Information on existing air quality has been obtained by collating the results of monitoring
carried out by DBC. Background concentrations for the site have been defined using the
recently updated national pollution maps published by Defra. These new maps cover the
whole country on a 1x1 km grid48.
Construction Effects
14.3.2
48
During demolition and construction the main potential effects are dust annoyance and locally
elevated concentrations of PM10. The suspension of particles in the air is dependent on
surface characteristics, weather conditions and on-site activities. Impacts have the potential
to occur when dust generating activities coincide with dry, windy conditions, and where
sensitive receptors are located downwind of the dust source.
http://laqm.defra.gov.uk/maps/maps2010.html
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14.3.3
Separation distance is also an important factor. Large dust particles (greater than 30μm),
responsible for most dust annoyance, will largely deposit within 100m of sources.
Intermediate particles (10-30μm) can travel 200-500m. Consequently, significant dust
annoyance is usually limited to within a few hundred metres of its source. Smaller particles
(less than 10μm) are deposited slowly and may travel up to 1km, however, the impact on the
short-term concentrations of PM10 occurs over a shorter distance. This is due to the rapid
decrease in concentrations with distance from the source due to dispersion.
14.3.4
The Greater London Authority (GLA, 2006) provides guidelines to determine the likely level
of risk construction and demolition impacts will have on local dust complaints and PM10
concentrations. Sites are categorised into low, medium and high risk (Table 14.1) based on
the size of the development, and potential for impacts at sensitive receptors, and the
appropriate level of mitigation consequently required. By applying the recommended
mitigation, the site is reduced to a low risk site.
Table 14.1: Risk Criteria for Control of Dust and Emissions from Construction
Risk
Criteria
High
Medium
Low
14.3.5



Development of over 15,000 square metres.
Development of over 150 properties.
Potential for emissions and dust to have significant impact on sensitive
receptors.



Development of between 1,000 and 15,000 square metres.
Development of between 10 to 150 properties
Potential for emissions and dust to have an intermittent or likely impact on
sensitive receptors



Development of up to 1,000 square metres
Development of one property and up to a maximum of ten
Potential for emissions and dust to have an infrequent impact on sensitive
receptors
The sensitivity of the study area to construction dust impacts is defined based on the
examples provided within the Institute of Air Quality Management (IAQM, 2012) guidance
(Table 14.2), taking into account professional judgement.
Table 14.2: Area Sensitivity Definitions
Sensitivity




European
Designated Site

More than 100 dwellings within 20m.
PM10 concentrations exceed the daily mean objective.
Contamination present.
Very sensitive receptors (schools / hospitals).
Construction activities in one area for more than one year.
High


10 – 100 dwellings within 20m.
PM10 concentrations approach the daily mean objective.
Nationally
Designated Site
Medium


Less than 10 dwellings within 20m.
PM10 concentrations below the daily mean objective.
Locally Designated
Site
Low


No dwellings within 20m.
PM10 concentrations well below the daily mean objective.
No designation
Very High
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14.3.6
Consideration was also given to wind and rainfall data. A wind rose from Heathrow weather
station for 2011 was used along with average rainfall data (1981-2010) obtained from the
Met Office website. The proximity of ecological receptors to the site has been determined
through the MAGIC website, provided by Defra49.
Significance Criteria
14.3.7
The construction impact significance criteria are based on:

‘Guidance on the Assessment of the Impacts of Construction on Air Quality and the
Determination of their Significance’, IAQM 2012;

‘The control of dust and emissions from construction and demolition Best Practice
Guidance’, GLA 2006;

‘Particulate Matter in the United Kingdom’, Air Quality Expert Group, 2005; and

Air Quality (England) Regulations, 2000 and Air Quality (England) (Amendment)
Regulations 2002.
14.3.8
The significance criteria take account of the risk of impact and the likely magnitude (taking
into account the scale and nature of the works, the proximity of sensitive receptors, and
existing conditions in the area) and the sensitivity of the receptors (as defined by the IAQM
guidance). The significance criteria also assume that mitigation appropriate to the level of
risk (defined in the mitigation section, based on the GLA 2006 guidance) is put into place.
14.3.9
Table 14.3 presents the significance criteria used to assess the construction impacts.
Table 14.3: Construction Phase Significance Criteria
Sensitivity of Area
Risk of Site Giving Rise to Dust Effects
High
Medium
Low
Without Mitigation
Very High
Major adverse
Moderate adverse
Moderate Adverse
High
Moderate adverse
Moderate Adverse
Minor Adverse
Medium
Moderate Adverse
Minor Adverse
Not Significant
Low
Minor Adverse
Not Significant
Not Significant
With Mitigation
49
Very High
Minor Adverse
Minor Adverse
Not Significant
High
Minor Adverse
Not Significant
Not Significant
Medium
Not Significant
Not Significant
Not Significant
Low
Not Significant
Not Significant
Not Significant
Available at: http://magic.defra.gov.uk/website/magic/
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Operational Effects – Road Traffic
Sensitive Locations
14.3.10 Relevant sensitive locations are places where members of the public might be expected to
be regularly present over the averaging period of the objectives. For the annual mean and
daily mean objectives that are the focus of the road traffic assessment, sensitive receptors
will generally be residential properties, schools, nursing homes, etc. When identifying these
receptors, particular attention has been paid to assessing impacts close to junctions, where
traffic may become congested, and where there is a combined effect of several road links.
14.3.11 Based on the above criteria, seven existing residential properties have been identified as
existing receptors for the assessment. These locations are described in Table 14.4 and
shown in Figure 14.1 at Appendix I.1. Receptors were modelled at a height of either 1.5m
representing ground floor exposure or, where ground floor exposure does not exist, 4.5m
representing first floor exposure.
Table 14.4: Description of Receptor Location
Receptor
Location
Height (m)
R1
Century House, 100 Leighton Buzzard Road
1.5
R2
1 Bury Green
1.5
R3
65 Bury Road
1.5
R4
154 Leighton Buzzard Road
1.5
R5
1 Marlowes
4.5
R6
53 Marlowes
1.5
R7
Bury Lodge, Queensway
1.5
Impact Predictions
14.3.12 Predictions of nitrogen dioxide, PM 10 and PM2.5 concentrations have been carried out for a
baseline year of 2011, and for a future year of 2014, both with and without the development
in place. In addition, concentrations have been predicted at nine diffusion tubes in proximity
to the site in order to verify the modelled results (see Appendix I.2 for further details on the
verification method).
14.3.13 Predictions have been carried out using the ADMS-Roads dispersion model (v3.1.24). The
model requires the user to provide various input data, including the emissions for each
section of road, and road characteristics (including road width, height above ground level,
and street canyon height, where applicable). It also requires meteorological data; the model
has been run using meteorological data from the Heathrow monitoring station (2012), which
is considered to be suitable for this area due to its proximity to the site and London.
14.3.14 Baseline Annual Average Daily Traffic (AADT) flows and the proportions of Heavy Duty
Vehicles (HDVs) were provided by the project Transport Consultants (SKM Colin Buchanan).
Traffic speeds have been estimated from local speed restrictions and take account of the
proximity to a junction. Traffic data used in this assessment are summarised in Appendix
I.3.
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14.3.15 Emissions were calculated using the recently released Emission Factor Toolkit (EFT) v5.2c,
which utilises NOx emission factors taken from the European Environment Agency COPERT
4 (v8.1) emission calculation tool. The traffic data were entered into the EFT, along with
speed data, to provide emission rates for each of the road links entered into the model.
Vehicle emissions are anticipated to reduce significantly in the future, but there is
considerable uncertainty about how rapidly this will occur. In order to take account of this
uncertainty, traffic data provided for the completion of the development (2015) have been
combined with emission factors and background concentrations from 2014.
Assessment Criteria
14.3.16 The NAQOs for NO2 and PM10, set out in the Air Quality Regulations (England) 2000 and the
Air Quality (England) (Amendment) Regulations 2002, are shown in Table 14.5.
Table 14.5: Nitrogen Dioxide and PM10 Objectives
Pollutant
Nitrogen dioxide (NO2)
Particulate matter (PM10)
Time Period
1-hour mean
Objective
200µg/m3
not to be exceeded more than 18 times a year
40µg/m3
Annual mean
24-hour mean
50µg/m3
not to be exceeded more than 35 times a year
40µg/m3
Annual mean
14.3.17 The objectives for NO2 and PM10 were to have been achieved by 2005 and 2004,
respectively, and continue to apply in all future years thereafter. Analysis of long term
monitoring data suggests that if the annual mean NO2 concentration is less than 60µg/m3
then the one-hour mean objective is unlikely to be exceeded where road transport is the
main source of pollution. This concentration has been used to screen whether the one-hour
mean objective is likely to be achieved50.
14.3.18 The Air Quality Strategy (2007) includes an exposure reduction target for smaller particles
known as PM2.5. These are an annual mean target of 25µg/m 3 by 2020 and an average
urban background exposure reduction target of 15% between 2010 and 2020.
14.3.19 A new air quality directive (2008/50/EC) was adopted in May 2008, and includes a national
exposure reduction target, a target value and a limit value for PM2.5, shown in Table 14.6.
The UK Government transposed this new directive into national legislation in June 2010
(Stationery Office, 2010).
50 Defra,
2009. Local Air Quality Management Technical Guidance LAQM.TG(09).
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Table 14.6: PM2.5 Air Quality Criteria
UK Objectives
Time Period
Objective / Obligation
To Be Achieved By
Annual mean
25µg/m3
2020
3 year running
annual mean
15% reduction in concentrations
measured at urban background sites
Between 2010 and 2020
Annual mean
Target value of 25µg/m3
2010
Annual mean
Annual mean
European
Obligations
Limit value of
25µg/m3
Stage 2 indicative Limit value of
20µg/m3
2015
2020
Exposure reduction target relative to
3 year Average
the AEI depending on the 2010 value
Exposure
of the 3 year AEI (ranging from a 0%
Indicator (AEI)a
to a 20% reduction)
2020
3 year Average
Exposure concentration obligation of
Exposure
20µg/m3
Indicator (AEI)
2015
a
The 3 year annual mean or AEI is calculated from the PM2.5 concentration averaged across all urban background
monitoring locations in the UK e.g. the AEI for 2010 is the mean concentration measured over 2008, 2009 and
2010.
Significance Criteria
14.3.20 There is no official guidance in the UK on how to describe the nature of air quality impacts,
nor to assess their significance. The approach developed by IAQM, subsequently
incorporated into the EPUK 2010 guidance (EPUK, 2010), has therefore been used within
this assessment to assist in describing the air quality impacts associated with the proposed
development with regard to road traffic impacts.
14.3.21 The guidance sets out three stages: determining the magnitude of change at each receptor,
describing the impact, and assessing the overall significance. Impact magnitude relates to
the change in pollutant concentration; the impact description relates this change to the air
quality objective (or limit value). Table 14.7 sets out the impact magnitude descriptors,
whilst Table 14.8 sets out the impact descriptors.
Table 14.7: Impact Magnitude for Changes in Ambient Pollutant Concentrations
Magnitude
Annual Mean NO2 and
PM10
Annual Mean PM2.5
Number of Days PM10
>50µg/m3
Large
≥ 4µg/m3
≥ 2.5µg/m3
≥ 4 days
Medium
2–
Small
0.4 –
Imperceptible
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<4µg/m3
<2µg/m3
< 0.4µg/m3
>1.25 –
2.5µg/m3
3 – 4 days
>0.25 –
1.25µg/m3
1 – 2 days
< 0.25µg/m3
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Table 14.8: Impact Descriptor for Changes in Concentration at a Receptor
Absolute Concentration with the
Development in Relation to
Objective / Limit Value
Small
Medium
Large
Above objective/limit value (a)
Minor
Moderate
Major
Minor
Moderate
Moderate
Not Significant
Minor
Minor
Not Significant
Not Significant
Minor
Just below objective/limit value
Below objective/limit value
(b)
(c)
Well below objective/limit value
Change in Concentration
(d)
Where there is an increase in concentrations, the absolute concentration relates to the ‘with development’ air
quality. Where there is a decrease in concentrations, the absolute concentration relates to the ‘without development’
air quality. Where concentrations increase the impact is described as adverse, and where it decreases as beneficial.
Where the magnitude of change is imperceptible (Table 14.7), the change is described as not significant.
(a) Above: >40µg/m3 annual mean NO2 or PM10, or >25µg/m3 annual mean PM2.5, or >35 days PM10 >50µg/m3
(b) Just below: 36 – 40µg/m3 annual mean NO2 or PM10, or 22.5 – 25µg/m3 annual mean PM2.5, or 32 – 35 days
PM10 > 50µg/m3
(c) Below: 30 – <36µg/m3 annual mean NO2 or PM10, or 18.75 – <22.5µg/m3 of annual mean PM2.5, or 26 – <32 days
PM10 > 50µg/m3
(d) Well below: < 30µg/m3 annual mean NO2 or PM10, or <18.75µg/m3 annual mean PM2.5, or < 26 days PM10
>50µg/m3
14.3.22 The guidance states that the assessment of significance should be based on professional
judgement, taking into account the following factors, with the overall air quality impact on the
scheme described as either ‘not significant’, ‘minor’, ‘moderate’ or ‘major’:

Number of properties affected by minor, moderate or major air quality impacts and a
judgement on the overall balance;

The magnitude of the changes and the descriptions of the impacts at the receptors i.e.
Tables 14.7 and 14.8 findings;

Whether or not an exceedence of an objective or limit value is predicted to arise in the
study area where none existed before or an exceedence area is substantially increased;

Whether or not the study area exceeds an objective or limit value and this exceedence is
removed or the exceedence area is reduced;

Uncertainty, including the extent to which worst-case assumptions have been made; and

The extent to which an objective or limit value is exceeded.
Operational Effects – Odour
14.3.23 Consideration is given to prevalent wind conditions in the area and the location of existing
receptors in order to determine the risk of odour impacts arising, and the requirement for
mitigation. The risk of odour impacts is determined based on the method set out in Appendix
3 of the Guidance on the Control of Odour and Noise from Commercial Kitchen Exhaust
Systems (Defra, 2005).
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Baseline Conditions
Local Air Quality Management
14.4.1
DBC has investigated air quality within its area as part of its responsibilities under the LAQM
regime. Air Quality Management Areas (AQMAs) have recently been declared in the
borough in three areas due to exceedences of the annual mean NO 2 objective. Two of these
AQMAs (Lawn Lane, Hemel Hempstead and London Road, Apsley) are within 1.5km of the
proposed development site.
Monitoring
14.4.2
DBC currently measures concentrations of NO 2 using diffusion tubes at 41 sites throughout
the borough. Diffusion tubes are supplied and analysed by Harwell Scientifics (ESG Didcot;
50% TEA in acetone). Five of these monitoring sites are located within approximately 1km
of the proposed development site. Available data for these sites are presented in Table
14.9. Data are also presented for those sites utilised in the model verification.
Table 14.9: Annual Mean NO2 Concentrations in Hemel Hempstead
Site ID
Site Location
Site Type
Annual Mean (μg/m3)
2007
2008
2009
2010
2011
2012
-
-
36.0
29.0
-
27.6
29.5
Sites Within 1km
DC76
The Cotterells
Kerbside
-
-
DC77
Cotterells 1
Roadside
-
-
DC78
Cotterells 2
Roadside
-
-
-
-
30.0
25.3
DC79
Cotterells 3
Roadside
-
-
-
-
30.0
34.7
DC67
Allandale
Roadside
-
-
-
-
28.1
28.7
Sites Utilised in Model Verification
DC57
Lawn Lane 1
Roadside
58.2
56.4
60.0
59.0
53.2
50.6
DC64
Lawn Lane 2
Roadside
40.1
37.5
40.0
38.0
39.3
36.9
DC65
Lawn Lane 3
Roadside
61.3
54.4
56.0
62.0
57.2
59.1
DC70
Lawn Lane 4
Roadside
-
-
-
-
39.9
40.5
DC66
London Road,
Apsley
Roadside
60.3
56.3
57.0
54.0
59.2
57.9
DC72
London
Featherbed
Roadside
-
-
-
-
35.8
-
DC73
Durrants Hill
Road
Roadside
-
-
-
-
33.4
31.2
DC74
Avia Close
Roadside
-
-
-
-
42.1
40.6
DC85
Health Centre,
London Road
Kerbside
-
-
-
-
33.0
38.7
Objective
40
40
40
40
40
40
Data for 2007-2011 taken from Air Quality Updating and Screening Assessment for Dacorum Borough Council.
Available at: www.dacorum.gov.uk/pdf/USA%202012.pdf
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2012 data provided by the Council, and bias adjusted using the national factor of 0.79 (ESG Didcot, 50% TEA in
acetone, spreadsheet version 03/13). Data have been annualised due to data capture <75%. See Appendix I.4 for
further details.
Exceedences highlighted in bold
14.4.3
Annual mean concentrations at those sites within 1km of the site have remained below the
annual objective for nitrogen dioxide during the 2007-2012 period. All sites where
exceedences have been measured in recent years are within areas which have recently
been declared as AQMAs. The data show that concentrations have remained similar over
the six year period.
14.4.4
Monitoring sites located in the Cotterells are likely to be most representative of air quality
within the proposed development site due to being within similar proximity to the Leighton
Buzzard Road (A4146).
14.4.5
DBC does not currently monitor concentrations of PM10 or PM2.5.
Background Concentrations
14.4.6
In addition to these measured concentrations, estimated background concentrations for the
study area have been obtained from the national maps (Table 14.10).
Table 14.10: Estimated Annual Mean Background Concentrations (µg/m3)
Year
14.4.7
NOx
NO2
PM10
PM2.5
2012
28.3 – 31.1
18.0 – 19.5
15.8 – 16.8
11.4 – 11.8
2014
25.8 – 28.5
16.8 – 18.2
15.4 – 16.3
11.0 – 11.4
Objectives
-
40
40
25
The mapped background concentrations are well below the relevant objectives.
Predicted Baseline Concentrations
14.4.8
The ADMS-Roads model has been run to predict baseline NO 2, PM10 and PM2.5
concentrations at each of the receptor locations identified in Table 14.4. Table 14.11 sets
out the results for the baseline scenarios.
Table 14.11: Predicted Baseline Concentrations of NO2, PM10 and PM2.5
Receptor
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NO2
PM10
Annual Mean
Annual Mean
Number of Days
>50µg/m3 a
Annual Mean
2012
2012
2012
2014
2012
2014
PM2.5
2014
2014
R1
43.4
38.4
20.6
19.5
4
3
14.6
13.6
R2
31.5
28.6
18.2
17.5
2
1
13.0
12.3
R3
29.6
27.3
18.1
17.5
1
1
12.9
12.3
R4
38.1
35.4
19.4
18.5
3
2
13.8
13.0
R5
37.7
32.5
19.1
18.1
2
1
13.6
12.7
R6
37.5
30.7
18.6
17.6
2
1
13.3
12.4
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Receptor
NO2
PM10
Annual Mean
Annual Mean
Number of Days
>50µg/m3 a
Annual Mean
2012
2012
2012
2014
2012
2014
PM2.5
2014
2014
R7
45.6
40.4
20.8
19.5
5
3
14.8
13.6
Objectives
40
40
40
40
35
35
25
25
Exceedences highlighted in bold
Annual mean in µg/m3
a
The number of days with PM10 concentrations greater than 50µg/m 3 have been estimated from the relationship with
the annual mean concentrations described in Defra, 2009.
14.4.9
The annual mean NO2 objective is predicted to be exceeded at receptors 1 and 7 in 2012
and at receptor 7 in 2014. At all other receptors annual mean NO2 concentrations are
predicted to be below the objective. Predicted baseline concentrations of PM 10 and PM2.5 are
well below the objectives in both years.
14.4.10 There are no predicted annual mean NO2 concentrations which exceed 60µg/m 3, and
therefore there are unlikely to be any exceedences of the hourly mean objective.
Potential Effects
Construction Phase
14.5.1
14.5.2
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The main potential effects during construction are dust deposition and elevated PM 10
concentrations. The following activities have the potential to cause emissions of dust:

Site preparation including delivery of construction material, erection of fences and
barriers;

Earthworks including digging foundations and landscaping;

Materials handling such as storage of material in stockpiles and spillage;

Movement of construction traffic including haulage, vehicles and plant movements;

Construction and fabrication of units; and

Disposal of waste materials off-site.
Typically the main cause of unmitigated dust generation on construction sites is from
demolition and vehicles using unpaved haul roads, and off-site from the suspension of dust
from mud deposited on local roads by construction traffic.
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14.5.3
The main determinants of unmitigated dust annoyance are the weather and the distance to
the nearest receptor. Based on the GLA criteria (Table 14.1), the site is classified as high
risk. Mitigation measures set out for high risk sites should therefore be required in order to
reduce the level of risk to low risk. The study area is considered to be of medium sensitivity
(Table 14.2) as although there are approximately 16 dwellings on Marlowes within 20m of
the site, background PM10 concentrations are well below the objective, and there are no
statutory designated nature conservation sites within close proximity to the site boundary,
the closest being the Roughdown Common SSSI approximately 1.8km from the site
boundary.
14.5.4
The wind rose for Heathrow weather station for 2012 (Figure 14.2, Appendix I.1), shows
that the dominant wind directions are from the southwest to the west. Winds from the
southwest occur for approximately 22% of the time and from the west for approximately 23%
of the time.
14.5.5
Wind speeds of moderate strength (3m/s) or greater are required to suspend dust in the air.
For approximately 30% of the time the wind speed was less than moderate, below which
dust is unlikely to become suspended in the air.
14.5.6
A daily rainfall of 0.2mm is considered sufficient to prevent fugitive dust generation. Analysis
of rainfall data for the area around the site shows that, over the 30 year period from 1981 to
2010, an average of 44 - 47% of days were ‘wet days’ (i.e. within rainfall over 0.2mm) when
there will be natural dust suppression.
14.5.7
For the majority of the time there will be little potential for dust generation even with no
mitigation in place because:

On approximately 44 – 47% of days the rainfall is greater than 0.2mm when there will be
natural dust suppression to minimise emissions of dust;

In winter months surfaces tend to stay damp for significant periods of time; and

30% of the time winds are typically less than moderate strength and would not suspend
dust in the air from stockpile and open surfaces.
14.5.8
There may, however, be periods when sufficient dust is generated and crosses the site
boundary to cause annoyance. This is more likely in the summer months, when higher
temperatures evaporate surface moisture more readily.
14.5.9
Predicted PM10 concentrations at the closest receptor to the site (R7) exceed 50µg/m3 for six
days a year (compared to the permitted 35) in 2011. As predicted baseline concentrations in
the area are low, it is unlikely that the construction activities would cause an exceedence of
the objective.
14.5.10 The number of construction vehicle movements will be verified to ascertain whether an
assessment will be required.
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Operational Phase
Road Traffic
14.5.11 Predicted concentrations of NO2, PM10 and PM2.5 at existing receptors in 2014, both with and
without the development in place, are presented in Table 14.12.
14.5.12 The annual mean NO2 objective is predicted to be exceeded at Receptor 7 in the 2014
baseline scenario, with an improvement predicted with the development in place. At all other
modelled existing receptors predicted pollutant concentrations are below the relevant
objectives whether the development proceeds or not. The changes in annual mean
concentrations and the number of days with PM 10 concentrations greater than 50µg/m 3 are
presented in Table 14.13. Based on the impact magnitude descriptors presented in Table
14.7, the changes in annual mean nitrogen dioxide concentrations range from imperceptible
to medium scale, whilst the changes in PM10 and PM2.5 concentrations and the number of
days with PM10 concentrations greater than 50µg/m 3, are all imperceptible or small.
14.5.13 Using the criteria set out in Table 14.8, the impact on PM10 and PM2.5 concentrations is
therefore described as not significant. The impacts on annual mean nitrogen dioxide
concentrations range from slight adverse at one location (R4) to moderate beneficial (at R7).
Table 14.12: Predicted Concentrations of NO2, PM10 and PM2.5 at Existing Receptors in 2014 (µg/m3)
2014 Baseline
Receptor
2014 With Development
a
NO2
PM10
Annual
Mean
Annual
Mean
Days
PM2.5
NO2
PM10a
Annual
Mean
Annual
Mean
Days
PM2.5
Annual
Mean
Annual
Mean
R1
38.4
19.5
3
13.6
37.7
19.4
3
13.5
R2
28.6
17.5
1
12.3
28.4
17.5
1
12.3
R3
27.3
17.5
1
12.3
27.4
17.5
1
12.3
R4
35.4
18.5
2
13.0
36.4
18.7
2
13.2
R5
32.5
18.1
1
12.7
30.5
17.7
1
12.5
R6
30.7
17.6
1
12.4
28.8
17.3
1
12.2
R7
40.4
19.5
3
13.6
38.1
19.1
2
13.4
Objectives
40
40
35
25
40
40
35
25
Exceedences highlighted in bold
Annual mean in µg/m3
a The number of days with PM10 concentrations greater than 50µg/m3 have been estimated from the relationship
with the annual mean concentrations described in Defra, 2009.
Table 14.13: Change in Predicted Concentrations brought about by the Development in 2014 (µg/m3)
Receptor
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NO2
PM10a
Annual Mean
(µg/m3)
Annual Mean
(µg/m3)
PM2.5
Days >50µg/m3
Annual Mean
(µg/m3)
R1
-0.7
-0.1
0
-0.1
R2
-0.3
0.0
0
0.0
R3
0.1
0.0
0
0.0
R4
1.0
0.2
0
0.1
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Receptor
NO2
PM10a
Annual Mean
(µg/m3)
Annual Mean
(µg/m3)
PM2.5
Days >50µg/m3
Annual Mean
(µg/m3)
R5
-2.0
-0.3
0
-0.2
R6
-1.9
-0.3
0
-0.2
R7
-2.3
-0.4
0
-0.3
a Based on unrounded results
Impact Significance
14.5.14 The air quality impacts of road traffic generated by the proposed development on human
health receptors is considered to be not significant according to the assessment criteria set
out in Paragraph 14.3.23. In particular, there is a general improvement in predicted
concentrations at the modelled receptor locations and only one property is affected by minor
adverse impacts, but there are no predicted exceedences of NAQOs.
Modelling Uncertainty
14.5.15 There are many components that contribute to the uncertainty in predicted concentrations.
The model used in this assessment is dependent upon the traffic data that have been input
which will have inherent uncertainties associated with them. There is then additional
uncertainty as the model is required to simplify real-world conditions into a series of
algorithms.
14.5.16 A disparity between the road transport emission projections and measured annual mean
concentrations of nitrogen oxides and NO 2 has recently been identified51. Whilst projections
suggest that both annual mean nitrogen oxides and NO2 concentrations were expected to
have fallen by around 15-25% over the past 6 to 8 years, at many monitoring sites levels
have remained relatively stable, or have even shown a slight increase. This pattern is
evident in the monitoring data presented in Table 14.9.
14.5.17 Model uncertainty can be reduced through model verification, in which model outputs are
compared with measured concentrations. Because the model has been verified and
adjusted against 2012 monitoring data, there can be reasonable confidence in the predicted
concentrations. The assessment has also utilised the most up-to-date emission factors and
background concentrations.
Operational Effects – Odour
14.5.18 The proposed kitchens for the foodstore and café have the potential to result in odour
releases from the building. Whether or not these odours cause a nuisance will depend on
the strength and nature of the odours, and the sensitivity of the receiving environment.
51
Carslaw, D, Beevers, S, Westmoreland, E and Williams, M, 2011. Trends in NOx and NO2 emissions and ambient
measurements in the UK. Available at: http://uk-air.defra.gov.uk/library/reports?report_id=645
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14.5.19 Defra Guidance on the Control of Odour and Noise from Commercial Kitchen Exhaust
Systems (Defra, 2005) states that the potential for odours from commercial kitchens is
influenced by three primary factors:

The size of the cooking facility;

The type of food prepared; and

The type of cooking appliances used.
14.5.20 The closest existing properties are located approximately 20m east of the proposed café.
Based on the dominant wind directions (southwest and west), there is the potential for
properties to the east to experience odours for 21% of the time and properties to the north
east for 24% of the time. A risk assessment has been carried out following the approach set
out in Appendix 3 of the Defra guidance on control of odour from commercial kitchens.
Based on this, there is considered to be a low to medium risk of odour impacts, requiring low
odour control measures.
Mitigation & Enhancement
Construction
14.6.1
The construction effects can be minimised through use of the recommended mitigation
measures outlined below. The mitigation measures should be included within a detailed
Construction Environmental Management Plan (CEMP) prepared by the Principal Contractor
to be agreed with DBC.
14.6.2
Dust control measures should be rigorously applied close to the boundaries of the site to
reduce the risk of dust impacts and public exposure to elevated PM 10 concentrations. The
relevant mitigation measures for high risk sites from the GLA Best Practice Guidance (GLA,
2006) should be implemented:
Site preparation:
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
Erect solid barriers to site boundary.

No bonfires on site.

Plan site layout – machinery and dust causing activities should be located away from
sensitive receptors.

All site personnel should be fully trained on the site pollution policy.

Trained and responsible manager on site during working times to maintain logbook of
routine site inspections and the details and action taken to minimise dust-causing
episodes.

Site haul routes should be hard surfaced.

Where possible use nearby rail or waterways for transportation to/from site.
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
Put in place real-time dust monitors across the site.
Construction traffic:

All vehicle engines should be switched off when not in use.

Vehicles should be cleaned and wheels washed before leaving the site.

Haul routes should be damped down or washed to reduce dust generation. Effective
cleaning of haul routes should use sprinkler systems to clean internal and external roads
on a daily basis if required.

All loads entering and leaving the site must be covered.

There should be no runoff of water or mud from the site.

On-road vehicles should comply with set emission standards.

All non-road mobile machinery to use ultra low sulphur tax exempt diesel where
available and be fitted with appropriate exhaust after-treatment from an approved list
managed by the energy saving trust (www.est.org.uk).

Minimise movement of construction traffic around the site.

Impose an appropriate site speed limit.
Demolition works:

Cutting equipment to use water as suppressant or suitable local extract ventilation.

Use enclosed chutes and covered skips.

Wrap or screen buildings to be demolished with a suitable material.
Site activities:

Minimise dust generating activities, for example the use of water as a dust suppressant
and dust extraction techniques where possible. Refer to the GLA Best Practice Guidance
for all dust minimisation methods.

Cover, seed or fence stockpiles to prevent wind generating dust.

The local authority must be notified of the use of a concrete crusher and a permit to
allow operation must be provided.
Operation
Road Traffic
14.6.3
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The air quality impacts of road traffic generated by the proposed development are
considered to be not significant. Therefore, mitigation measures for the operational phase of
the development are not necessary.
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Odour
14.6.4
Based on the findings of the risk assessment, low odour control measures are likely to be
required for the foodstore’s café ventilation system. The design and installation of an
appropriate system could be addressed through a planning condition to be satisfied once the
precise details of the café and ventilation system to be installed are known.
Residual Effects
Construction
14.7.1
With the proposed mitigation, the site is reduced to a low risk category (GLA, 2006), and
construction dust is considered to affect sensitive receptors infrequently. Sensitive receptors
will only be affected when mitigation measures are not operating effectively; these receptors
may also experience short-term elevated PM10 concentrations during construction.
However, it is unlikely that the 24-hour PM10 concentration will be exceeded at these
receptors as the existing background PM10 concentrations are low.
14.7.2
The residual impact of the construction of the proposed development will be short term, with
construction dust infrequently affecting sensitive receptors, and impacts are judged to be not
significant (see Table 14.3).
Operational Phase
14.7.3
The impact of road traffic emissions from traffic generated by the proposed development on
air quality at existing receptors has been determined, and is judged to be not significant,
even without mitigation in place.
14.7.4
With the odour mitigation outlined in the Defra guidance the impact of the foodstore café on
existing dwellings should be effectively mitigated to a minor impact.
Summary
14.8.1
An air quality assessment has been undertaken to identify the effects of the proposed
development during construction and operation. Air quality in close proximity to the site is
currently good, however DBC has recently declared two AQMAs within 1.5km of the site.
14.8.2
The construction works have the potential to create dust and the development site is
considered as high risk under the GLA guidance, with the surrounding area considered as
medium sensitivity. During construction it will be necessary to apply a package of mitigation
measures to minimise the potential for dust deposition and elevated PM 10 concentrations.
With these measures in place the overall impacts during construction are judged to be not
significant.
14.8.3
The operational impacts of increased emissions arising from traffic generated by the
proposed development have been assessed. Concentrations of NO 2, PM10 and PM2.5 have
been predicted at existing receptors. Road traffic impacts are considered to be not
significant.
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14.8.4
The operation of the foodstore kitchens have the potential to create odour effects at existing
properties, although the risk is considered low to medium, and ‘low control’ measures are
likely to be adequate.
References
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
Carslaw, D., Beevers, S., Westmoreland, E. and Williams, M. (2011). Trends in NOx and
NO2 emissions and ambient measurements in the UK. Available: http://ukair.defra.gov.uk/library/reports?report_id=645.

Department for Communities and Local Government (2012), National Planning Policy
Framework (NPPF). Available:
www.gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pd
f

Department of the Environment, Food and Rural Affairs (Defra)(2005). Guidance on the
Control of Odour and Noise from Commercial Kitchen Exhaust Systems. January 2005.
Available at: www.defra.gov.uk/publications/files/pb10527-kitchen-exhaust-0105.pdf

Department of the Environment, Food and Rural Affairs (Defra) (2012). 2010 Based
Background
Maps
for
NOx,
NO2,
PM10
and
PM2.5.
Available:
http://laqm.defra.gov.uk/maps/maps2010.html.

Department of the Environment, Food and Rural Affairs (Defra) in partnership with the
Scottish Executive, The National Assembly for Wales and the Department of the
Environment for Northern Ireland (2009). Local Air Quality Management Technical
Guidance, LAQM.TG(09). HMSO, London.

Department of the Environment, Food and Rural Affairs (Defra) (2007) The Air Quality
Strategy for England, Scotland, Wales and Northern Ireland, Stationery Office, London.

Greater London Authority (2006). Best Practice Guidance: The control of dust and
emissions from construction and demolition, GLA, London.

Institute of Air Quality Management (2012). Guidance on the Assessment of the Impacts
of Construction on Air Quality and the Determination of their Significance.

Stationery Office, 1990. Environmental Protection Act,1990.

Statutory Instrument 2000, No 921, The Air Quality (England) Regulations 2000, HMSO,
London.

Statutory Instrument 2002, No 3034, The Air Quality (England) (Amendment)
Regulations 2002, HMSO, London.

Statutory Instrument 2007, No. 64, The Air Quality Standards Regulations 2007, HMSO,
London.
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
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Statutory Instrument 2010, No 1001. The Air Quality Standards Regulations 2010,
HMSO, London
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15
Archaeology
Introduction
15.1.1
This chapter has been prepared by Archaeological Solutions Ltd (AS) and presents
information relating to the potential survival of archaeological remains within the site and the
impact of the proposed development upon those remains. Current policy relating to
archaeology is presented; this is followed by the current baseline conditions and an
assessment of the impacts of the proposed development.
15.1.2
The chapter is informed by an archaeological desk-based assessment of the site (Peachey
and Newton 2012; Appendix J.2) and the results of an archaeological trial trench evaluation
conducted on that part of the site to the north of the current Dacorum Way (Adams 2010;
Appendix J.3).
Policy Context
National Planning Policy Framework
15.2.1
The National Planning Policy Framework (DCLG 2012) states that those parts of the historic
environment that have significance because of their historic, archaeological, architectural or
artistic interest are heritage assets. The National Planning Policy Framework (NPPF) aims
to deliver sustainable development by ensuring that policies and decisions that concern the
historic environment recognise that heritage assets are a non-renewable resource, take
account of the wider social, cultural, economic and environmental benefits of heritage
conservation, and recognise that intelligently managed change may sometimes be
necessary if heritage assets are to be maintained for the long term.
15.2.2
The NPPF requires applications to describe the significance of any heritage asset, including
its setting that may be affected in proportion to the asset’s importance and the potential
impact of the proposal.
15.2.3
The NPPF aims to conserve England’s heritage assets in a manner appropriate to their
significance, with substantial harm to designated heritage assets (i.e. scheduled
monuments) only permitted in exceptional circumstances when the public benefit of a
proposal outweighs the conservation of the asset. The effect of proposals on nondesignated heritage assets must be balanced against the scale of loss and significance of
the asset, but non-designated heritage assets of demonstrably equivalent significance may
be considered subject to the same policies as those that are designated. The NPPF states
that opportunities to capture evidence from the historic environment, to record and advance
the understanding of heritage assets and to make this publicly available is a requirement of
development management. This opportunity should be taken in a manner proportionate to
the significance of a heritage asset and to the impact of the proposal, particularly where a
heritage asset is to be lost.
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Dacorum Borough Council Local Plan 1991-2011
15.2.4
Local Policy is contained in the ‘Dacorum Borough Council Local Plan 1991-2011’, adopted
in 2004.
15.2.5
Policy 1, Sustainable Development Framework, of the Dacorum Borough Council Adopted
Local Plan 1991-2011 states that:
“Policy 1 sets out the overall sustainability aims of the Plan. This is supported by the key
Local Plan objectives set out below...
... (d) To protect the Borough’s historical and archaeological heritage.”
15.2.6
Policy 118 relates directly to important archaeological remains and states that:
“Planning permission will not be granted for development which would adversely affect
scheduled ancient monuments or other nationally important sites and monuments, or their
settings. English Heritage will be consulted on all planning applications affecting Scheduled
Ancient Monuments.
On archaeological sites or monuments of more local importance and their settings, physical
preservation in situ will be the preferred option and applications may be refused. The
County Archaeological Group will be consulted on all planning applications affecting areas of
archaeological significance and archaeological potential.
Where advice indicates that a proposed development will affect remains of archaeological
significance or areas of archaeological potential, developers will be expected to provide the
results of an archaeological evaluation as part of their planning application.
Where the Council considers that physical preservation of archaeological remains in situ is
not merited, planning permission will be subject to satisfactory provision being made for
excavation and recording. Conditions and/or agreements will be used to secure the
following work, depending on the nature of the site:
(a) An adequate archaeological excavation of the site prior to the commencement of the
works; and/or
(b) The observation of archaeological experts of the site works as they progress; and/or
(c) The recording of remains by archaeological experts and the publication of the results;
and/or
(d) The provision of facilities, including access over an agreed period of time; and/or
(e) Such other measures as may be necessary to protect the archaeological integrity of the
site.
Where appropriate the Council will encourage the enhancement of archaeological remains
and their settings.”
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Dacorum Borough Council Core Strategy (Modifications to the Pre-Submission Core
Strategy, January 2013)
15.2.7
Policy CS27 relates to the quality of the historic environment. It states that:
“All development will favour the conservation of heritage assets.
The integrity, setting and distinctiveness of designated and undesignated heritage assets will
be protected, conserved and if appropriate enhanced.
Development will positively conserve and enhance the appearance and character of
conservation areas. Negative features and problems identified in conservation area
appraisals will be ameliorated or removed.
Features of known or potential archaeological interest will be surveyed, recorded and
wherever possible retained.”
Methodology
15.3.1
Information regarding the known and potential archaeology of the site has previously been
collated through the production of an archaeological desk-based assessment (Peachey
2009) and the execution of an archaeological trial trench evaluation (Adams 2010; Appendix
J.3). These works were conducted on that part of the current site that comprises the
Dacorum Campus of West Herts College, or that part of it to the north of the current
Dacorum Way. In order to cover the entirety of the site, an updated archaeological deskbased assessment (Newton and Peachey 2012; Appendix J.2) was compiled in order to
inform this chapter.
Baseline Data Collection: Archaeological Desk-Based Assessment
15.3.2
Information was sought from a variety of available sources in order to meet the objectives of
the assessment.
15.3.3
Archaeological databases: The standard collation of all known archaeological sites and find
spots within Hertfordshire is derived from the Hertfordshire Historic Environment Record
(HCC HER). Significant entries within an approximate 500m radius of the site are listed in
an appendix of Appendix J.2 and plotted in Appendix J.1, Figure 15.2.
15.3.4
Historical and cartographic sources: The principal sources for this type of evidence were the
Hertfordshire Archives and Local Studies (HALS). Relevant documents are reproduced in
Appendix J.1, Figures 15.3-15.10.
15.3.5
Secondary sources: The principal sources of secondary material were Hertfordshire Archives
and Local Studies, as well as AS’s own in-house library. Unpublished sources regarding the
assessment area, such as previous field evaluation reports and desk-based assessments,
have also been consulted.
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15.3.6
Geological/geotechnical information: A description of the superficial and solid geology of the
local and surrounding area was compiled in order to assess the likely presence and potential
condition of any archaeological remains on the site. This information was drawn from
appropriate maps published by the Geological Survey of Great Britain (BGS 1978) and the
Soil Survey of England and Wales (SSEW 1983).
Baseline Data Collection: Archaeological Trial Trench Evaluation
15.3.7
In October 2010 Archaeological Solutions Ltd carried out an archaeological trial trench
evaluation at the site. The evaluation was commissioned by G. Dolden & Associates Ltd (on
behalf of West Hertfordshire College) and was carried out as a requirement of the local
authority prior to the determination of a planning application proposing comprehensive
redevelopment of the site. It followed the submission of a desk-based assessment compiled
to characterise the archaeological potential of this site (Peachey 2009). The fieldwork was
conducted by Matthew Adams BA who also compiled the resultant report. The evaluation
was conducted in accordance with a brief issued by Hertfordshire County Council Historic
Environment Unit (HCC HEU) (dated 15th September 2010) and a written scheme of
investigation compiled by AS (dated 24th September 2010), and approved by HCC HEU.
15.3.8
Twelve trial trenches were excavated, totalling 325m. The trenches varied in length between
10m and 50m; all were 1.6m in width and were linear in plan. The trenches were positioned
to investigate areas previously known to contain 19th century buildings and also to
investigate areas previously thought to be undisturbed (Appendix J.1, Figure 15.1).
Assessment Methodology
15.3.9
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The significance of likely effects has been assessed by taking into account the sensitivity of
archaeological heritage features and the potential magnitude of change. Magnitude of
change is a function of the nature, scale and type of disturbance, or damage to the
archaeological feature. The sensitivity of the heritage assets depends on factors such as the
condition of the site and the perceived heritage value/importance of the site, in terms of
national, regional or local statutory or non-statutory protection and grading of the asset. The
criteria for determining receptor importance are outlined in Table 15.1. Assessment of the
Significance of Effects is governed by the standards expected under the Institute for
Archaeologists’ (IfA) ‘Standards and Guidance for Archaeological Desk-based Assessments’
(1994, revised 2008) and follows the relevant sections in the Department for Communities
and Local Governments’ ‘Amended Circular Environmental Impact Assessment’ (1996).
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Table 15.1 – Criteria for determining receptor importance
Importance of
Receptor
Equivalent or Comparable to
Very High
World Heritage Sites, certain Scheduled Monuments
High
Scheduled Monuments, assets included on the Historic Environment Record of
national importance
Medium
Important sites on a district level, assets with a district-level importance
associated with educational purposes or cultural appreciation, assets included
on the Historic Environment Record of regional importance
Low
Important sites on a local level, assets with a parish-level importance associated
with educational purposes or cultural appreciation, assets included on the
Historic Environment Record of local importance
Very Low
Heritage assets with no significant value or interest, assets that are so damaged
as not to merit inclusion at a higher grade
Uncertain
Heritage assets for which there is not sufficient information to determine
importance, e.g. isolated findspots, unconfirmed cropmark sites, sites known
only from documentary references with no physically confirmed location
Baseline Conditions
Introduction
15.4.1
The sum of the updated archaeological desk-based assessment (Peachey and Newton
2012; Appendix J.2) and the archaeological trial trench evaluation of that part of the site to
the north of the current Dacorum Way (Adams 2010; Appendix J.3) are the following
conclusions regarding archaeological potential and previous ground disturbance.
Archaeological potential relates to the potential for archaeological remains of particular dates
to exist with the site and is based on the known evidence from the site and the surrounding
area. The archaeological potential of the site for each of the major archaeological time
periods is presented below and this is followed by relevant summaries relating to the
available evidence which is presented in Appendices J.2 and J.3. Previous ground
disturbance relates to the likelihood of survival of those potential archaeological remains
within the site.
Archaeological Potential
15.4.2
Prehistoric – Low. Despite being located in the valley of the river Gade which is considered
to have been a focus of prehistoric activity, no prehistoric archaeology has been recorded in
the close vicinity of the site. Furthermore, no prehistoric evidence was recorded during the
trial trench evaluation of the site (Adams 2010) and no alluvial sequences that may lend
themselves to Palaeoenvironmental reconstruction were present.
15.4.3
Roman – Low. Only an isolated Roman brooch has been recorded in the vicinity, and the
site is located significantly to the south of the Gadebridge Roman villa. The presence of
Roman archaeology in the vicinity of the site is, therefore, considered to be unlikely.
15.4.4
Medieval – Low. The site is located to the south of the extent of the medieval settlement,
and probably comprised meadowland neighbouring the river. Cartographic sources indicate
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little development in the area until the later post-medieval period. Hunns (2000, 8) has stated
that medieval remains are most likely to occur in the area south of St Mary's Church to
Queensway and west of High Street, across to the Leighton Buzzard Road. The proposed
lies beyond the margins of this area to the south. The area in which the lies is understood to
have been historically prone to flooding and, therefore, unsuitable for settlement.
15.4.5
Post-Medieval – High. Cartographic sources indicate little development within the site until
the late post-medieval/early modern period. A significant number of 18th century buildings
survive to the north on Hemel Hempstead’s High Street and at least one building of this date
is known to the immediate east of the site on the opposite side of Marlowes. The site was
occupied by in excess of 60 premises or residences and water cress beds built in the mid to
late 19th century. Remains of buildings constructed during the 19th century development of
the site were identified during the trial trench evaluation of that part of the site to north of the
current Dacorum Way (Adams 2010; Appendix J.3).
15.4.6
Modern – High. The mid to late 19th century buildings were not demolished until the mid-20th
century when the site was redeveloped with the buildings of the current West Herts College
and Civic Centre.
15.4.7
The site lies within the valley of the river Gade. Dacorum Borough Council (2012) state that
Prehistoric occupation is known to be concentrated along the Gade valley. Indeed, the river
valleys of the region have most likely always been attractive for settlement but a survey by
Holgate (1995) does not show any Mesolithic or Neolithic sites along the Gade. Hunns
(2000, 2-3) has noted, however, that the Hemel Hempstead area has a very high
concentration of Prehistoric and Roman activity, including nationally significant multi-period
and transitional sites. He suggests that, on this basis, it is reasonable to assume that further
important archaeology from these periods remains to be found, especially within the Gade
valley. The river Bulbourne, which passes by Hemel Hempstead to the south-west is also
known to be rich in evidence of Prehistoric activity; for example at Berkhamstead Neolithic
flint mines, ditches, postholes, lithic artefacts and other evidence for settlement has been
recorded (Hastie 1999, 7). The position of the assessment site, on the banks of the river
Gade, therefore, indicates that there may be a potential for Prehistoric remains to be present
at this location. However, no finds of Prehistoric date have been recorded in the area
surrounding the site.
15.4.8
Palaeoenvironmental reconstruction and the modelling of environmental conditions in all
phases of prehistory is identified as an important research subject for Eastern England
(Medlycott 2011). The known potential for prehistoric remains in the Gade and Bulbourne
valleys indicates that dateable alluvial sequences may be present within the assessment
site, suggesting a potential for valuable information contributing to research goals associated
with this subject. However, during the archaeological trial trench evaluation of the northern
part of the assessment site (Adams 2010; Appendix J.3) no alluvial deposits were identified.
This suggests that within the bounds of the site, the potential for environmental sampling to
provide detailed palaeoenvironmental information may be limited.
15.4.9
The assessment site is significantly removed from the focal points of Romano-British activity
in the Hemel Hempstead area, notably the Bronze Age settlement identified at Gadebridge
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Lane and the Roman villa recorded in Gadebridge Park. An isolated bronze brooch of
Roman date is the only pre-medieval find recorded in the close vicinity of the site.
15.4.10 The extent of the settlement at Hemel Hempstead through the medieval period until the midlate 19th century has been well defined and does not incorporate the site. The site appears
to have remained as meadowland to the east of the river Gade, and to the south of the mill
and manor at the Bury, which formed the southern extent of the town. The land to the south
of the medieval core of Hemel Hempstead was prone to flooding in the region of Two Waters
and Marlowes in antiquity, preventing settlement of the area (Hunns 2000, 13). It is
conceivable, however, that some aspects of the manorial complex may have extended in to
land currently comprising the site. Dury and Andrews’ 1766 (Appendix J.1, Figure 15.3)
map suggests that there may have been buildings at the northern end of the assessment
site, which may logically have been part of the Bury complex, but this depiction may not be a
true or accurate representation of the landscape, and does not appear on any subsequent
cartographic sources (Appendix J.1, Figures. 15.4-15.10). During trial trench evaluation of
the site (Adams 2010), only two features of late post-medieval date were identified and it is
not possible to associate these directly with the manorial complex.
15.4.11 Development to the west of the site, on the western side of the Marlowes, is also depicted on
Dury and Andrews’ 1766 map (Appendix J.1, Figure 15.3).
15.4.12 The expansion of Hemel Hempstead in the mid to late 19th century incorporated the site into
the urban character of the town, and is amply illustrated on the 1877 and 1898 Ordnance
Survey maps (Appendix J.1, Figs. 15.6 and 15.7). This development included the laying
out of Alma Road and Bath Street, which both lay within the site, and a relatively dense
cluster of buildings fronting on to Alma Road, Bath Street, Bury Road and Marlowes.
15.4.13 The site contained in excess of 60 premises or residences including the Drill Hall
(Volunteer), a Smithy, a Public House (the Sebright Arms), a Methodist Chapel, water works,
public baths and possibly, initially, a school. Late 19th century business directories describe a
wide range of utilitarian commercial businesses on Marlowes and Alma Road but do not
allow individual premises to be identified. By the mid-20th century these buildings were
described as “a rather run-down subsidiary trading area, including low grade domestic
buildings,” and the area was subsequently cleared to make way for the New Town
development. The western part of the site also contained watercress beds adjacent to the
river Gade, which would probably have comprised sunken, gravel-filled compartments
designed to provide the ideal semi-aquatic conditions required for the growth of this crop.
These appear to have been developed following the production of the 1843 Tithe Map
(Appendix J.1, Figure 15.5) and prior to the production of the 1877 Ordnance Survey map
(Appendix J.1, Figure 15.6) which shows a comparatively large water-filled area in the
western central part of the site; this is marked as ‘watercress beds’ on the 1898 Ordnance
Survey map (Appendix J.1, Figure 15.7).
15.4.14 The physical remains of the 19th century development of the site were identified during the
trial trench evaluation of that part of the site to the north of the current Dacorum Way. The
evaluation revealed a concentration of 19th – 20th century activity to the north, east and
centre of the site. These are the remains of buildings clearly identifiable on the 1925 OS
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map (Appendix J.1, Figure 15.8). Trench 2 contained the remains of buildings that fronted
on to Bury Road (Now Queensway) including parts of the old Drill Hall. Trench 4 contained
the remains of cellared buildings that fronted on to the Marlowes and two brick plinths
possibly associated with a more substantial building that might have been the public house
on the corner of Alma Road. A large concentration of demolition and concrete at the
southern end of Trench 4 may relate to the location of Alma Road which was removed during
the 1960’s.
15.4.15 Trenches 5 and 6 also contained the remains of cellared buildings that fronted on to the
Marlowes. The eastern end of Trench 6 contained the cellar and cellar stairs of the building
adjacent to the existing Methodist Church. The centre of the site contained predominantly
demolition material and a surviving wall (W1040) of buildings located to the north-west of the
Methodist Church and some garden material. A ‘beehive’ style drain (M1039) had also
survived intact. Some minor peripheral structures were also present in Trench 12. Trench
11, to the west, was located overlying the site of the ‘watercress beds’ marked on 19th
century Ordnance Survey maps; it revealed the least disturbed ground and contained three
discrete features, which appeared to be of later post-medieval date.
15.4.16 The southern part of the site (to the south of the current Dacorum Way) has not been subject
to trial trench evaluation. The character and extent of archaeological deposits in this part of
the site, therefore, remains unknown. On the basis of the evidence available from the
northern part of the site and from cartographic sources, it may be reasonable to suggest that
similar deposits will be present in this part of the site to those recorded in the northern part of
the site. However, it remains possible that earlier archaeological features and deposits may
survive in parts of this southern part of the site that have not previously been developed.
Cartographic sources suggest that the western end of this part of the site has previously
been subject to little or no development.
15.4.17 The master plan for the New Town of Hemel Hempstead was drawn up in 1947, and the
Dacorum College of Further Education was constructed in the second stage of development,
opening in May 1963. Initially, the site contained buildings equating wholly or partially to the
modern blocks B (Library), C, D, F, G, H, J, the Hall, Connexions Building and one building
in the north-west corner, with the remaining buildings subsequently added in the later 20 th
century. It also contained the new town hall (currently described as the civic centre) and
bordered further public buildings which lay to the south. In April 1991 Dacorum College
merged with Watford College and Cassio College to become part of the newly created West
Herts College.
Previous Ground Disturbance
15.4.18 The construction of the mid to late 19th century buildings across the entirety of the site along
with Alma Road and Bath Road will have resulted in a high level of ground disturbance, that
is likely to have truncated pre-existing archaeological remains that were present within the
site. This ground disturbance has been demonstrated by the archaeological trial trench
evaluation that was conducted within the northern part of the current site (Adams 2010;
Appendix J.3). The trial trench evaluation revealed the area in which the watercress beds
were formerly located to be the least disturbed part of the site. The redevelopment of the
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site in the 1960s, comprising the Dacorum College of Further Education and the new Town
Hall is also likely to have resulted in significant ground disturbance, particularly within the
footprint of each building.
15.4.19 That part of the site within which the Civic Centre lies (to the south of Dacorum Way) has not
been subject to archaeological trial trench evaluation. Therefore, the extent of previous
ground disturbance has not been physically examined in this area. Given the extent of 19th
century development across the site, indicated by the available cartographic sources, it may
be predicted that 19th century disturbance, similar to that recorded in the northern part of the
site, will exist in that part of the site to the south of the current Dacorum Way.
Potential Effects
15.5.1
The proposed new development comprises the demolition of all of the existing buildings
within the site and the construction of a new college building, a supermarket and petrol
station, with associated parking, and additional college development covered by an outline
planning application.
15.5.2
The footprint of this proposed development will cover or impact upon the bulk of the
assessment site. The proposed new supermarket building incorporates an undercroft car
park.
15.5.3
All intrusive groundworks associated with the removal of the extant buildings and with the
construction of the new buildings, the provision of services to these buildings, the re-routing
of the river Gade and any re-profiling that may be necessary have the potential to truncate
any archaeological remains that may exist within the site.
15.5.4
The direct effects on sub-surface archaeological remains of the proposed development will
occur in the short-term as intrusive groundworks commence. Following the completion of
construction, effects on sub-surface archaeological remains will cease. This is unless the
proposed development, or its operation, alters ground conditions within the site affecting the
conditions under which archaeological remains may be preserved in the surrounding area
but this is considered to be unlikely.
15.5.5
In light of the evidence recorded during the trial trench evaluation (Adams 2010; Appendix
J.3) of the part of the site to the north of Dacorum Way, the proposed development will
impact upon archaeological remains of later post-medieval and 19th century date. While it
may be anticipated from the overall archaeological potential of the site and from the results
of the trial trenching that the development of the southern part of the site will impact only on
archaeology of similar dates, the absence of remains of earlier dates has not been
confirmed.
15.5.6
Overall, the effect of the construction of the proposed development on archaeological
remains may be considered to be a minor adverse effect. Significant truncation of any preexisting remains is likely to have occurred during the development that has occurred within
the site since the 19th century. Despite the known concentration of prehistoric occupation in
the wider Gade Valley, trial trench evaluation within the site has identified no evidence of
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prehistoric activity or any deposits that may contribute to an understanding of the prehistoric
environment in this area.
15.5.7
The built environment, industry and infrastructure, and towns are all archaeological research
subjects identified as being of importance for the post-medieval and early modern period in
Eastern England (Medlycott 2011, 78-79). The 19th century building remains demonstrated
to exist within the site (Adams 2010; Appendix J.3) may be considered to contribute to an
understanding of these subjects. These remains are likely to be truncated or removed
completely as a result of the proposed development. On this basis they may be considered
to represent receptors of low to medium importance and their loss to relate to a moderate to
moderate/substantial impact. However, as was shown during analysis of the results of the
trial trench evaluation (Adams 2010; Appendix J.3), it is possible to identify the existing
remains with the buildings shown on Ordnance Survey mapping from the 19th and early 20th
centuries. These maps provide a permanent record of the 19th century development of this
part of Hemel Hempstead and, therefore, the loss of these remains may be considered to be
a negligible effect of the proposed development.
Mitigation Measures
15.6.1
The most effective way to mitigate against the loss of archaeological remains as a result of
the proposed development is through preservation by record. This process usually begins
with trial trench evaluation to identify the character, extent and quality of any archaeological
remains that may be present and, if extensive remains are present, may lead to
archaeological excavation. Trial trench evaluation has already been undertaken for that part
of the site to the north of the current Dacorum Way (Adams 2010; Appendix J.3).
15.6.2
Despite the overall potential of the valley of the river Gade to contain evidence for prehistoric
occupation, the archaeological desk-based assessment of the site suggested that there was
only limited potential for such remains within the site (Peachey 2009; Peachey and Newton
2012; Appendix J.2). This was demonstrated during the trial trench evaluation which
recorded no prehistoric remains and no deposits contributing to the modelling or
reconstruction of the prehistoric environment in this area. Indeed, the trial trench evaluation
recorded no archaeological remains earlier in date than post-medieval and identified the
remains of 19th century buildings known to have occupied the site and which are recorded
on cartographic sources of that date. As such, it is suggested that no further mitigation is
required for that part of the site to the north of the current Dacorum Way.
15.6.3
Given the extensive trial trenching of the northern part of the site and the limited
archaeological potential that has been demonstrated for the part of the site south of
Dacorum Way (based on the evidence presented in Appendices J.2 and J.3) further
trenching should not be necessary. If required by HCC HEU it could be secured through
condition.
Residual Effects
15.7.1
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Residual effects on archaeology are minimal. Archaeological remains will still be lost and
therefore precluded from being subject to any more advanced recording techniques that may
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be developed in the future. However, mitigation measures provide a permanent record of
the archaeological remains identified within the site. This data and information can be
studied and analysed and has the potential to contribute to a greater understanding of the
past and to the achievement of certain research aims proposed in the archaeological
research agenda for Eastern England (Medlycott 2011). Although such a contribution is
likely to be minimal, this can be considered to represent a long-term minor positive residual
effect of the proposed development on the study of archaeology in the area.
Summary
15.8.1
An archaeological desk-based assessment (Peachey and Newton 2012; Appendix J.2) of
the site has demonstrated that it is unlikely to contain archaeological remains earlier in date
than the post-medieval period. This is despite the known concentration of evidence for
prehistoric settlement in the valley of the river Gade, within which the site lies; no remains of
prehistoric date have previously been recorded within the vicinity of the site.
15.8.2
The 19th century growth of Hemel Hempstead resulted in fairly widespread development
within the site. Any archaeological remains that may have existed within the site prior to this
are likely to have been truncated by groundworks associated with development at this time.
Further disturbance of any pre-existing archaeological remains would have occurred during
clearance of the site and further development during the mid-20th century.
15.8.3
A trial trench evaluation (Adams 2010; Appendix J.3) of that part of the site to the north of
the current Dacorum Way did not identify any archaeological remains earlier in date than
post-medieval or any alluvial deposits from which palaeoenvironmental reconstruction might
be carried out. This evaluation recorded fairly extensive 19th century building remains which
can be identified as representing the buildings shown on 19 th and early 20th century
Ordnance Survey mapping. As these cartographic sources already comprise a permanent
record of the 19th century character of this part of Hemel Hempstead it is suggested that
further archaeological mitigation through excavation is not required in the northern part of the
site. The part of the site south of the current Dacorum Way has not been subject to
archaeological trial trench evaluation. However, based on evidence that shows the limited
archaeological potential on this part of the site and findings of trial trenching on the northern
part, additional trial trenching should not be required.
15.8.4
Residual effects of the proposed development on archaeology are considered to be
negligible.
15.8
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References

Adams, M. C. 2010 West Hertfordshire College, Dacorum Campus, Marlowes, Hemel
Hempstead, Hertfordshire. An Archaeological Evaluation, Archaeological Solutions Ltd
unpublished report 3673

Dacorum Borough Council 2004, Dacorum Borough Council Adopted Local Plan 19912011, Dacorum Borough Council
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
Dacorum Borough Council 2013, Dacorum Borough Council Core Strategy
(Modifications to the Pre-Submission Core Strategy). Published Jan 2013, Dacorum
Borough Council

Department for Communities and Local Government, 1996, Amended Circular on
Environmental Impact Assessment; a consultation paper, Department for Communities
and Local Government

Department for Communities and Local Government 2012, National Planning Policy
Framework, Department for Communities and Local Government, London

Hastie, S. 1999 Berkhamstead: an illustrated history, Alpine Press, Hertfordshire

Holgate, R. 1995 ‘Early prehistoric settlement of the Chilterns’, In R. Holgate (ed.),
Chiltern Archaeology: Recent Work. A Handbook for the Next Decade, 3-16. The Book
Castle, Dunstable

Hunns, T. 2000, Hemel Hempstead Extensive Urban Survey Project Assessment
Report, Hertfordshire County Council, Hertford

Institute of Field Archaeologists (IFA) 2008 Standard and Guidance for Archaeological
Desk-Based Assessments. IFA, Reading

Medlycott, M. (ed.) 2011, Research and Archaeology revisited: a revised framework for
the East of England, ALGAO East of England Region, East Anglian Archaeology
Occasional Papers 24

Peachey, A. 2009 West Herts College, Hemel Hempstead Campus, Hertfordshire. An
Archaeological Desk-Based Impact Assessment, Archaeological Solutions Ltd
unpublished report 3405

Peachey, A. and Newton, A. A. S. 2012 West Herts College and Dacorum Civic Centre,
Hemel Hempstead, Hertfordshire.
An Archaeological Desk-Based Assessment,
Archaeological Solutions Ltd unpublished report 4176

Soil Survey of England and Wales 1983, Legend for the 1:250,000 Soil Map of England
and Wales. Harpenden
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16
Built Heritage
Introduction
16.1.1
This chapter has been prepared by CgMs Consulting and presents an assessment of the
likely effects of the development proposals on heritage assets within the site and its
environs.
16.1.2
Heritage assets are defined by the Government in the National Planning Policy Framework
(2012) as:
“A building, monument, site, place, area or landscape identified as having a degree of
significance meriting consideration in planning decisions, because of its heritage interest.
Heritage assets include designated heritage assets and assets identified by the local
planning authority (including local listing).”
16.1.3
This ES Chapter summarises baseline conditions, establishes the significance of heritage
assets in and within the vicinity of the proposed development site and presents an
assessment of the scale, nature and significance of potential effects on heritage assets,
considering the mitigation measures incorporated within the designs.
16.1.4
The assessment is informed by a Built Heritage Baseline Assessment (at Appendix K.1),
which includes full details of the built heritage assets considered as part of the impact
assessment process.
16.1.5
The aims and objectives of this ES Chapter are:

To describe the historic landscape, including any buildings of historic or architectural
interest that may be affected by the proposals;

To provide an assessment of their significance; and

To provide an assessment of the scale and nature of any potential residual effects that
may remain after mitigation.
Policy Context
National Legislation and Planning Policy
16.2.1
Where any development may affect designated or undesignated assets, there is a legislative
framework to ensure the proposals are designed and considered with due regard for their
effects on the historic environment. This extends from primary legislation under the Planning
(Listed Buildings and Conservation Areas) Act 1990. The relevant legislation in this case
extends from Sections 66 and 72, which state that special regard must be given by the
authority in the exercise of planning functions to the desirability of preserving or enhancing
listed buildings and their setting and conservation areas and their setting respectively.
16.2.2
The National Planning Policy Framework (March 2012) lays down the current policy regime
that states that applications should consider the potential effects of development on Heritage
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Assets. This term includes both designated heritage assets, which possess a statutory
designation (including listed buildings, conservation areas and registered parks and
gardens), as well as undesignated heritage assets (which are identified by the local planning
authority, often through their conservation area appraisals process or through a Local List).
16.2.3
The national policy framework encourages intelligent, imaginative and sustainable
approaches to managing change.
English Heritage has defined this approach as
‘constructive conservation’, promoting a positive and collaborative approach to conservation
that focuses on actively managing change. It aims to “recognise and reinforce the historic
significance of places, while accommodating the changes necessary to ensure their
continued use and enjoyment.” (Constructive Conservation in Practice, English Heritage,
2009)
16.2.4
The NPPF promotes sustainable development as a fundamental theme in planning and
provides a series of ‘Core Planning Principles’ (paragraph 17). These core principles of
sustainable development highlight that planning should be a creative exercise in finding
ways to enhance and improve the places in which people live their lives; that it should secure
high quality design and a good standard of amenity; and that heritage assets should be
conserved in a manner appropriate to their significance, so that they can be enjoyed for their
contribution to the quality of life for this and future generations.
16.2.5
Section 7, ‘Requiring Good Design’, reinforces the importance of good design in achieving
sustainable development, by ensuring the creation of inclusive and high quality places. This
section of the NPPF affirms, in paragraph 58, the need for new design to function well and
add to the quality of the area in which it is built, establish a strong sense of place and
respond to local character.
16.2.6
Section 12, ‘Conserving and Enhancing the Historic Environment’, paragraphs 126-141,
relate to the historic environment, and development which may have an effect upon it. This
section provides a framework for planning authorities, historic environment professionals and
property owners to work within when development is proposed. This framework:
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Identifies the need to recognise ‘designated heritage assets’ and undesignated heritage
assets;

Promotes the desirability of sustaining and enhancing the significance of heritage assets;

Looks to protect the settings of designated heritage assets;

Seeks to preserve and enhance the character and appearance of conservation areas;

Looks to focus on evidence bases, requiring applicants to provide proportionate
information on the heritage assets a development might impact upon, including an
assessment of the magnitude of these impacts, and further requiring that local
authorities identify and asses the significance of those assets;
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
Requires applicants who wish to demolish or substantially alter a designated heritage
asset to provide a strong evidence based argument for the permanent loss of such an
asset; and

Provides that the setting of heritage assets is considered as part of the decision making
process, and favours applications that seek to protect, or mitigate against harm to, that
setting.
Local Policy
16.2.7
The saved Adopted Local Plan (2001, retained in 2007) remains the principal source of local
planning policy for Dacorum Borough, with its saved policies proposed for supersession with
the formal adoption of the Core Strategy. Policy 11 (Quality of Development) states that a
high standard is expected in all development proposals, particularly with regard to layout,
design, scale, bulk, height, massing, materials and landscaping. It also states that proposals
should include measures to enhance the local landscape; respect the townscape, density
and general character of the area in which it is set; and retain, not adversely affect and
where appropriate enhance important historical or architectural features. Policy 114 (Historic
Parks and Gardens) and Policy 120 (Development within Conservation Areas) both similarly
state that inappropriate development in or near designated heritage assets will not be
permitted.
16.2.8
The Dacorum Core Strategy has currently reached ‘Modifications to the Pre-Submission
Core Strategy’ (January 2013). Policy CS27: Quality of the Historic Environment of the Draft
Core Strategy states that all development will favour the conservation of heritage assets and
that the integrity, setting and distinctiveness of designated and undesignated heritage assets
will be protected, conserved and, if appropriate, enhanced.
It further states that
development will positively conserve and enhance the appearance and character of
conservation areas. Negative features and problems identified in conservation area
appraisals will be ameliorated or removed.
16.2.9
The Gade Zone Planning Statement (April 2012) guides the broad policy, development and
design for the Gade Zone in Hemel Hempstead town centre, one of the seven Character
Zones identified by Dacorum Borough Council (DBC) in Hemel Hempstead and in which the
site is located. The document is a material consideration in the determination of planning
applications within the Gade Zone. It highlights that regeneration of the Gade Zone will
make a significant contribution to achieving the vision for Hemel Hempstead Town Centre,
identified within the Core Strategy.
16.2.10 The Hemel Hempstead Town Centre Masterplan (2011 – 2021) (Adopted January 2013 as a
Supplementary Planning Document in support of the Core Strategy) states an objective to
ensure that future development enhances the town centre’s natural assets and builds upon
and complements its unique identity and heritage. It highlights the seven Character Zones of
the town, their historic contexts, heritage assets and key issues. The site falls within the
Gade Zone, which is highlighted as representing major development opportunities that are
critical to the achievement of the Masterplan’s long term regeneration objectives, including
opportunities for new educational and civic facilities and also a new supermarket.
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16.2.11 The Town Centre Masterplan is supported by the Hemel Hempstead Heritage Improvement
Strategy (November 2012). The Vision for this document states that:
“The Heritage Improvement Strategy will maximise the potential and economic benefit of
heritage within Hemel Hempstead town centre. This supports the creation of an attractive,
vibrant and sustainable town through the development and implementation of the Town
Centre Masterplan.”
16.2.12 It is therefore likely that the Gade Zone will experience considerable changes up to 2021 as
the Masterplan is fulfilled. The Heritage Improvement Plan also highlights the intention to
seek funding to invest in improving the linkages between the Old Town and the New Town,
reuse of historic buildings, reinstatement of traditional features and introduction of a public
realm strategy.
Non-Statutory Guidance
16.2.13 Conservation Principles (English Heritage, 2008) offers guidance with regard to the
assessment of heritage significance, describing a range of values which enable the
significance of assets to be established systematically, with the four main ‘heritage values’
being: evidential, historical, aesthetic and communal. Conservation Principles further
emphasises that “considered change offers the potential to enhance and add value to
places…it is the means by which each generation aspires to enrich the historic environment.”
(paragraph 25) ‘Setting’ is defined in this document as:
“The surroundings in which a place is experienced, its local context, embracing present and
past relationships to the adjacent landscape.” (page 71)
16.2.14 The Setting of Heritage Assets (English Heritage, 2011) provides guidance on the
management of change within the setting of heritage assets, defining ‘setting’ as ‘the
surroundings in which a heritage asset is experienced. Its extent is not fixed and may
change as the asset and its surroundings evolve.’ Setting is also described as being a
separate term to curtilage, character and context; whilst it is largely a visual term, setting,
and thus the way in which an asset is experienced, can also be affected by noise, vibration,
odour and other factors.
Methodology
16.3.1
This ES Chapter and its supporting technical Appendix K.1 has been prepared in
accordance with the requirements of the EIA regulations, as well as the NPPF (2012),
English Heritage guidance, particularly Conservation Principles (English Heritage, 2008),
The Setting of Heritage Assets (English Heritage, 2011) and Seeing the History in the View
(English Heritage, 2011).
16.3.2
The assessment presented in this Chapter has been prepared in parallel with and informed
by the Townscape Views Impact Assessment (Chapter 11), which includes as part of its
assessment an appraisal of viewpoints from listed buildings. This Built Heritage Chapter
remains distinct, however, and presents a wider assessment of heritage assets, including
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reference to effects on heritage significance and setting, which is more than a purely visual
concept. As a result, the findings between the chapters may differ.
16.3.3
This chapter and its accompanying technical appendix have also been prepared in
accordance with the Environmental Impact Assessment Scoping Opinion issued by DBC in
October 2012, Appendix A.4.
16.3.4
DBC stated in their scoping opinion comments (received separately to the formal Scoping
Response letter, dated 24th October 2012) that the proposed development would affect the
Hemel Hempstead High Street Conservation Area (which the site slightly overlaps) and the
setting of The Bury (Grade II*) and a range of other designated and undesignated heritage
assets within its vicinity. It further stated that the designs of the proposed buildings need to
be assessed for their effects on cultural heritage.
16.3.5
This assessment takes into consideration designated and undesignated heritage assets
within, or within the environs of the site whose setting may be affected by the development.
In order to identify assets which are likely to experience an effect, whether direct or indirect,
an area within a 250m radius of the site boundary has been identified and assessed. DBC
did not specify a particular baseline for the assessment of heritage assets but it is
considered that a 250m radius provides an appropriate baseline for assessment in this case.
This wider area will be referred to in this assessment as the ‘study area’.
16.3.6
The Setting of Heritage Assets (English Heritage, 2011) sets out a five staged process for
assessing the implications of proposed development on setting:
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
Identification of heritage assets which are likely to be affected by proposals: the
guidance states that if development is capable of affecting the contribution of a heritage
asset’s setting to its significance, or the appreciation of its significance, it can be
considered as falling within the asset’s setting. It distinguishes that an impact on setting
does not necessarily equate with harm and may represent positive enhancements,
based on a detailed understanding of the individual heritage asset’s significance. LPAs
are advised to have due regard to proportionality for the assessment required by the
applicant and to minimise the need to analyse large numbers of assets in detail.

Assessment of whether and what contribution setting makes to the identified heritage
assets: this assessment is informed by an understanding of the history and development
of the site and its surrounding environs, using historic mapping where available. The
assessment should also be informed by the physical surroundings of the asset, including
its relationship with other assets, the way in which the asset is experienced and the
asset’s associations and patterns of use. All this information will provide a baseline for
establishing the effects of a proposed development on the significance of a heritage
asset.

Assessing the effects of proposed development on the significance of a heritage asset:
this assessment involves identifying the range of effects that proposed development may
have on the setting of the heritage assets, which will be evaluated as beneficial, neutral
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or harmful. The location and siting, form and appearance, permanence and any other
effects of proposals will all inform the assessment process.
16.3.7

Maximising enhancement and reduction of harm on the setting of heritage assets:
measures to reduce harm could include relocation of all or part of the proposed scheme,
changes to the layout. Where harm cannot be eliminated, design quality of the proposed
development may be one of the main factors in assessing the balance of harm and
benefit. Where a development cannot be adjusted and where some degree of harm to
setting is unavoidable, appropriate screening may be required to reduce the extent of
harm caused.

The final decision about the acceptability of proposals: the LPA’s decision will depend on
a range of circumstances, deciding applications on a case by case basis, and should
recognise in their decision making that all heritage assets are not of equal importance
and the contribution made by their setting to their significance also varies.
The first and second bullet points of this methodology have been addressed in the
accompanying technical Appendix K.1 and form the baseline for that assessment. The third
and fourth bullet points will be addressed in this ES chapter. The fifth bullet point relates to
the LPA’s assessment of the application, but is included here for clarity about the
assessment process laid down in English Heritage’s guidance.
Baseline Data Collection
16.3.8
Heritage assets are recorded in national or local historic environment databases and in this
instance, assets have been identified from English Heritage’s National Heritage List for
England and DBC online mapping.
16.3.9
In addition, the preparation of the baseline assessments included site visits covering the site
and the study area along with a map progression exercise and the application of professional
judgement. Assessment during site visits was based on exterior views only from publicly
accessible points.
Receptor Sensitivity
16.3.10 The significance of a heritage asset is defined in the NPPF Glossary as:
“The value of a heritage asset to this and future generations because of its heritage interest.
That interest may be archaeological, architectural, artistic or historic. Significance derives
not only from a heritage asset’s physical presence, but also from its setting.”
16.3.11 Determination of a heritage asset’s sensitivity, or importance, is based on existing statutory
designations. Criteria for establishing the significance / importance of heritage assets are
described in Table 16.1.
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Table 16.1: Importance of Heritage Assets
Sensitivity /
Importance
Description
International
Buildings or structures of international importance, including World Heritage
Sites.
Structures and buildings inscribed as of universal importance as World
Heritage Sites.
Other buildings or structures of recognised international importance.
National
Listed Buildings and Registered Parks and Gardens.
District
Conservation Areas.
Local
Historic buildings on a 'local list'. Undesignated built assets of local
significance.
None
Buildings which, following research and evaluation, are identified as being of
no built heritage significance.
Magnitude of Effect
16.3.12 Determining the magnitude of effect is based on an understanding of how, and to what
extent, the proposed development would have an effect upon heritage assets and their
significance.
16.3.13 The magnitude of effect is rated as Severe, Major, Moderate, Minor or Not Significant.
Where the receptor is of no heritage significance, the magnitude of effect becomes
irrelevant. The nature of effects is also assessed as:

Direct or Indirect; and

Adverse or Beneficial.
16.3.14 The criteria for assessing the magnitude and nature of effect are set out in Table 16.2.
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Table 16.2: Magnitude of Effects
Magnitude and
Nature of Effect
Direct Effects
Indirect Effects
Major Adverse
Demolition of built heritage assets or
loss of significant feature in a
registered park or conservation area.
Substantially harmful change in the
setting of a built heritage asset,
registered park or conservation area.
Moderate Adverse
Harmful alteration (but not demolition)
of a built heritage asset, or significant
feature in a registered park or
conservation area.
Less than substantial harm to the
setting of a built heritage asset,
registered park or conservation area.
Minor Adverse
Alterations to a built heritage asset, or
significant feature in a registered park
or conservation area resulting in
minor harm.
Minor harm to the setting of a built
heritage asset, registered park or
conservation area.
Not Significant
Negligible direct effect to a built
heritage asset, registered park or
conservation area.
Negligible perceptible change or harm
to the setting of a built heritage asset,
registered park or conservation area
Minor Beneficial
Alterations to a built heritage asset,
registered park or conservation area
resulting in minor beneficial effects.
Minor enhancement to the setting of a
built heritage asset, registered park or
conservation area. E.g.: decrease in
visual or noise intrusion on the setting
of a built heritage asset.
Moderate
Beneficial
Alterations to a built heritage asset,
registered park or conservation area
resulting in moderate beneficial
effects.
Significant reduction or removal of
visual or noise intrusion on the setting
of a heritage asset.
Improvement of the wider landscape
setting of a built heritage asset or
conservation area.
Moderate enhancement to the setting
of the built heritage asset, registered
park or conservation area.
Major Beneficial
Arrest of physical damage or decay to
a built heritage asset or structure.
Alteration to a built heritage asset or
conservation
area
resulting
in
significant beneficial effect.
Significant enhancement to the
setting of a built heritage asset or
conservation area, its cultural heritage
amenity and access or use.
Significance of Effects
16.3.15 Once the magnitude and nature of the effects are identified, the significance of the effects of
the proposed development on heritage assets can be determined by considering:

The importance/sensitivity of the asset; and

The magnitude of effect to the asset.
16.3.16 Table 16.3 presents a matrix that demonstrates how the significance of effect has been
established, also informed by professional judgement. Although not shown in the table, the
outcome will be adverse or beneficial depending on the nature of the effect.
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Table 16.3: Significance of Effects
Magnitude Of Effect
Importance of Heritage
Assets
Major
Moderate
Minor
Not Significant
International Importance
Major
Major
Major
Not Significant
National importance
Major
Major/Moderate
Moderate
Not Significant
District importance
Major/Moderate
Moderate/ Minor
Minor
Not Significant
Minor
Minor
Not Significant
Not Significant
Not Significant
Not Significant
Not Significant
Not Significant
Local importance
None
* Effects can either be beneficial or adverse.
Summary of Methodology
16.3.17 In summary, following an assessment of the baseline conditions as presented in Appendix
K.1, the methods used to define the potential effects on built heritage assets associated with
the proposed scheme are as follows:

An evaluation of the sensitivity or importance of built heritage assets (based on
existing designations and professional judgement where assets have no formal
designation);

Prediction of the nature and magnitude of the likely effects upon the heritage
significance of identified built heritage assets;

Determination of what mitigation measures are required during the design and
construction of operational lifetime of the Proposed Scheme in order to mitigate any
adverse effects; and

Quantification of any residual effects that might remain after mitigation measures are
applied.
Assumptions
16.3.18 The assessment of the scale of effects is based on professional experience, by qualified
specialists, gained on other major developments across central and southern England.
Potential effects on built heritage have been considered in terms of inter-visibility and other
environmental changes typically arising from development of the scale proposed.
Baseline Conditions
16.4.1
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The site of the proposed development is currently in use as the West Hertfordshire College
campus and part of the Dacorum Civic Centre. It is bounded to the north, east and west by
Queensway, Marlowes and Leighton Buzzard Road respectively. The southern extent of the
site is bounded by the library, which falls outside of the site boundary but remains within the
Gade Zone. The landscape surrounding the site is primarily urban in character, with
residential estates to the east and west, the Hemel Hempstead new town to the south and a
more semi-urban character to the north around Gadebridge Park.
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16.4.2
The Built Heritage Baseline Assessment (Appendix K.1) details baseline historic
environment conditions on and surrounding the development site within the 250m study
area. This section provides a summary of the findings.
16.4.3
It has been identified that the site boundary overlaps the boundary of the Hemel Hempstead
High Street Conservation Area (DHA39), including the grassed lawns along the southern
edge of Queensway associated with the College, but the site otherwise contains no
designated heritage assets.
16.4.4
38 listed buildings have been identified as falling within the 250m study area. A number of
listed buildings are located along the streets that define the site boundaries, with views
across the site proposed for redevelopment. Many other listed buildings are located to the
north, along the old High Street, some of which have no views towards the site.
16.4.5
Hemel Water Gardens is a Grade II Registered Park (DHA40), located approximately 50m to
the south of the site boundary where it stretches south along Leighton Buzzard Road. The
long and thin shape of the gardens has the effect that only part of the northern section falls
within the study area and is enclosed by buildings along Waterhouse Street and Combe
Street.
16.4.6
DBC have identified in the Hemel Hempstead Heritage Improvement Study a number of
unlisted buildings which they consider make positive contributions to the character of the
High Street Conservation Area. These buildings have been included within this assessment
as undesignated heritage assets. One such building, the former Wesleyan Chapel, now
known as the Marlowes Methodists Chapel (identified as undesignated heritage asset (a))
falls within the site.
Tables 16.4 and 16.5 list the designated and undesignated heritage assets that have been
identified as falling within the study area, with the respective designations. Figures 1 and 2
in Appendix K.2 to this ES chapter depicts the study area and location of designated and
undesignated heritage assets. The importance of assets is identified according to the
methodology presented in Table 16.1.
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Table 16.4: List of Designated Heritage Assets Within 250m Study Area
CgMs ID
DHA1
DHA2
DHA3
DHA4
DHA5
DHA6
DHA7
DHA8
DHA9
DHA10
DHA11
DHA13
DHA14
DHA15
DHA16
DHA17
DHA18
DHA19
DHA20
DHA21
DHA22
DHA23
DHA24
DHA25
DHA26
DHA27
DHA28
DHA29
DHA30
DHA31
DHA32
DHA33
DHA34
DHA35
DHA36
DHA37
DHA38
DHA39
DHA40
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Name
51, Marlowes
The Bury
4, Queensway
Marlowes Baptist Church
Numbers 6 and 8, and wrought
iron front railings, Queensway
Old Marlowes House
Little Marlowes House
23 and 25, Queensway
10, 12 and 14, Queensway
27 and 29, Queensway
57 and 59 Marlowes
63 and 65, Marlowes
Charter Tower
67, Marlowes
Lloyd's Bank
Garden Walls of Manor House
The White Hart Public House
75 and 77, Marlowes
36, High Street
Rose and Crown Public House
Lockers Cottage
38, High Street
79, Marlowes
40, High Street
81, Marlowes
83 and 85, Marlowes
44 and 44a High Street
27, High Street
25, High Street
29, High Street
Church Of St Mary
33-39, High Street
Town Hall
The King's Arms Public House
The King's Arms Public House
45, 47 and 47a, High Street
The Old Bell Public House
Hemel Hempstead High Street
Conservation Area
Hemel
Water
Gardens
Registered Park and Garden
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Grade
II
II*
II
II
Importance
National
National
National
National
Location
Marlowes
Queensway
Queensway
Marlowes
II*
National
Queensway
II*
II
II
II
II
II
II
II*
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
I
II
II
II
II*
II
II*
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
National
N/A
District
Marlowes
Marlowes
Queensway
Queensway
Queensway
Marlowes
Marlowes
Gadebridge Park
Marlowes
Queensway
Gadebridge Park
High Street
Marlowes
High Street
High Street
Bury Hill
High Street
Marlowes
High Street
Marlowes
Marlowes
High Street
High Street
High Street
High Street
High Street
High Street
High Street
High Street
High Street
High Street
High Street
Hemel Hempstead Old
Town
II
National
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Table 16.5: List of Undesignated Heritage Assets within 250m study area
CgMs ID
Name
Importance
Location
a
Marlowes Methodists Church
Local
Marlowes, within site boundary
b
7-33, Marlowes
Local
Marlowes
c
Bury Lodge
Local
Queensway
d
43, Marlowes
Local
Marlowes
e
37, Marlowes
Local
Marlowes
f
5-21 (odd numbers), Queensway
Local
Queensway
g
20, High Street
Local
High Street
h
24, High Street
Local
High Street
i
9-15 (odd numbers), High Street
Local
High Street
j
28, High Street
Local
High Street
k
21 and 23, High Street
Local
High Street
l
1, Waterhouse Street
Local
Waterhouse Street
m
31, High Street
Local
High Street
n
132-148, Marlowes
Local
Marlowes
o
49, High Street
Local
High Street
p
Marlowes Multi Storey Car Park
Local
Marlowes
Scoping of Heritage Assets
16.4.7
Document1
Following a site assessment and assessment of heritage assets within the 250m study area,
a number of built heritage assets were identified as not being affected by the proposed
development, where the site makes no, or negligible, contribution to their settings. Details of
these assets are provided within Appendix K.1, which provides a full consideration of the
settings of these assets; these sites have not been excluded from assessment, but have
been assessed as being extremely unlikely to experience significant effects as a result of the
proposed development and are, as such, excluded from further assessment in this chapter.
The following unaffected assets have therefore been excluded from further assessment:
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Table 16.6: Designated Heritage Assets Excluded from Further Assessment
CgMs ID
Name
Grade
DHA14
Charter Tower
II*
DHA17
Garden Walls of Manor House
II
DHA18
The White Hart Public House
II
DHA20
36, High Street
II
DHA21
Rose and Crown Public House
II
DHA23
38, High Street
II
DHA25
40, High Street
II
DHA28
44 and 44a High Street
II
DHA29
27, High Street
II
DHA30
25, High Street
II
DHA31
29, High Street
II
DHA33
33-39, High Street
II
DHA34
Town Hall
II
DHA35
The King's Arms Public House
II
DHA36
The King's Arms Public House
II*
DHA37
45, 47 and 47a, High Street
II
DHA38
The Old Bell Public House
II*
Table 16.7: Undesignated Heritage Assets excluded from further assessment
CgMs ID
Name
Importance
Location
g
20, High Street
Local
High Street
h
24, High Street
Local
High Street
i
9-15 (odd numbers), High Street
Local
High Street
j
28, High Street
Local
High Street
k
21 and 23, High Street
Local
High Street
l
1, Waterhouse Street
Local
Waterhouse Street
m
31, High Street
Local
High Street
n
132-148, Marlowes
Local
Marlowes
o
49, High Street
Local
High Street
p
Marlowes Multi Storey Car Park
Local
Marlowes
Potential Effects
Potential Construction Effects
16.5.1
Potential effects during construction on the heritage assets identified have been assessed in
accordance with the methodology outlined in Section 16.3. The assessment scenario is
during the construction of the whole site, including site clearance and associated demolition.
16.5.2
The constructional, indirect, short term effects on built heritage assets can include effects
such as noise, dust and vibration, in addition to visual effects on views to and from heritage
assets. Visual effects will include the presence of construction equipment (including any
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cranes) and hoardings in the short term and these views will change as the construction
phases progress. A Construction Environmental Management Plan (CEMP) will be
implemented for the site to reduce the effects of construction. This is covered in Chapter 4
of the ES.
16.5.3
The proposed scheme will involve clearance of the existing buildings on the site, including
the Wesleyan Chapel known as Marlowes Methodists Church (undesignated heritage asset
(a)) dating to 1890. This building has been identified by DBC as an undesignated heritage
asset and its loss will be mitigated by an appropriate level of building recording,
proportionate to its heritage significance and as agreed with the Council.
16.5.4
The Hemel Hempstead High Street Conservation Area (DHA39) boundary overlaps the site
boundary by approximately 5m. Also in close proximity to the northern boundary of the site
is The Bury (Grade II* listed, DHA2). The demolition of poor quality temporary classrooms
featuring in glimpsed views from the highly graded listed building will be an improvement
within the setting of the conservation area and the listed building. Construction equipment
and hoardings will feature within the settings of these heritage assets, although these
construction effects are temporary and short term in nature.
16.5.5
Heritage assets located to the north east of the site along Queensway and the lower section
of the High Street will be affected by views of construction equipment and hoardings,
particularly Lloyds Bank (DHA16) which has clear views south west towards the site, but
these effects of construction are temporary and short term in nature.
16.5.6
The construction of the proposed development will also affect heritage assets located along
Marlowes, many of which have high levels of inter-visibility with the southern and eastern
parts of the site. The historic settings of the mostly early nineteenth century listed buildings
along Marlowes have been considerably altered in the 1960s when the former residential
street of Alma Road (located to the north of the site) was entirely demolished and
redeveloped with the Civic Centre and the College. The substantial level of change that has
already taken place within the settings of these listed buildings reduces their sensitivity to
further changes in this area.
16.5.7
Also of heritage significance in this vicinity are the views of the Grade I listed St Mary’s
Church (DHA32) and in particular, its spire, located to the north of the site at an elevated
position on the edges of the valley. These views represent a visual link between the New
and Old Towns which may be affected in places by construction equipment on the skyline.
However, these construction effects will be indirect, temporary and short term in nature.
16.5.8
Some undesignated assets are identified as experiencing some visual effects of
construction, but these effects will be indirect, temporary and short term in nature, also being
proportionate to their lower and local level of importance.
16.5.9
The potential construction effects upon the identified heritage assets are summarised in
Tables 16.8 and 16.9.
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Table 16.8: Potential Construction Effects for Designated Heritage Assets
CgMs
ID
Description
Importance of
Heritage Asset
Explanation of Effect (Prior to Mitigation)
DHA1
51, Marlowes
National
Views of construction equipment and hoardings from
the listed building, but these will be of a short term
and temporary nature.
National
Removal of poor quality temporary classrooms
featuring in glimpsed views from the highly graded
listed building. Some views south towards
construction equipment and hoardings, but these will
be of a short term and temporary nature and partly
blocked by established yew trees along the northern
edge of Queensway.
National
Views of construction equipment and hoardings from
the listed building, which will also feature in the
background of south western facing views of the listed
building along Queensway, but these will be of a short
term and temporary nature.
National
Views of construction equipment and hoardings
across most of the site from the listed building, but
these will be of a short term and temporary nature.
The setting of this building, already much changed by
the 1960s redevelopment of the site, will also be
affected by the loss of the Marlowes Methodists
Church, which would be demolished.
DHA2
DHA3
Document1
The Bury
4,
Queensway
DHA4
Marlowes
Baptist
Church
DHA5
Numbers 6
and 8, and
wrought iron
front railings,
Queensway
National
Some limited views of construction equipment and
hoardings from the listed building, which will also
feature in the background of south western facing
views of the listed building along Queensway, but
these will be of a short term and temporary nature.
DHA6
Old
Marlowes
House
National
Views of construction equipment and hoardings from
the highly graded Grade II* listed building, but these
will be of a short term and temporary nature.
DHA7
Little
Marlowes
House
National
Views of construction equipment and hoardings from
the listed building, but these will be of a short term
and temporary nature.
National
Some limited views of construction equipment and
hoardings from the listed building, which will also
feature in the background of south western facing
views of the listed building along Queensway, but
these will be of a short term and temporary nature.
National
Some limited views of construction equipment and
hoardings from the listed building, which will also
feature in the background of south western facing
views of the listed building along Queensway, but
these will be of a short term and temporary nature.
DHA8
23 and 25,
Queensway
DHA9
10, 12 and
14,
Queensway
DHA10
27 and 29,
Queensway
National
Some limited views of construction equipment and
hoardings from the listed building, which will also
feature in the background of south western facing
views of the listed building along Queensway, but
these will be of a short term and temporary nature.
DHA11
57 and 59
Marlowes
National
Views of construction equipment and hoardings from
the listed building, but these will be of a short term
and temporary nature.
DHA12
16 and 18,
High Street
National
Views of construction equipment and hoardings from
the listed building, which will also feature in the
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CgMs
ID
Description
Importance of
Heritage Asset
Explanation of Effect (Prior to Mitigation)
background of south western facing views of the listed
building along Queensway, but these will be of a short
term and temporary nature.
Document1
DHA13
63 and 65,
Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA15
67, Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA16
Lloyd's Bank
National
Prominent views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA19
75 and 77,
Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA22
Lockers
Cottage
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA24
79, Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA26
81, Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA27
83 and 85,
Marlowes
National
Limited views of construction equipment and
hoardings from the listed building, but these will be of
a short term and temporary nature.
DHA32
Church Of St
Mary
National
Construction equipment may block some views of the
church spire but these will be of a short term and
temporary in nature.
DHA39
Hemel
Hempstead
High Street
Conservation
Area
District
Site boundary overlaps with designated area,. Views
of construction equipment and hoardings would affect
the conservation area and its setting but these will be
of a short term and temporary nature.
DHA40
Hemel Water
Gardens
Registered
Park
National
Limited views of construction equipment relating to
access improvements from Leighton Buzzard Road
from the northern edge of the registered park, but
these will be of a short term and temporary nature.
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Table 16.9: Potential Construction Effects on Undesignated Heritage Assets
CgMs
ID
Description
Importance
of Heritage
Asset
Explanation of Effect (Prior to Mitigation)
a
Marlowes
Methodist
Chapel
Local
This building will be demolished in its entirety. The
effects of demolition will be mitigated by building
recording at a level appropriate to its significance.
b
7-33,
Marlowes
Local
Views of construction equipment and hoardings from the
undesignated heritage asset across the site, but these
will be of a short term and temporary nature.
c
Bury Lodge
Local
Views of construction equipment and hoardings from the
undesignated heritage asset, but these will be of a short
term and temporary nature.
d
43, Marlowes
Local
Views of construction equipment and hoardings from the
undesignated heritage asset, but these will be of a short
term and temporary nature.
e
37, Marlowes
Local
Views of construction equipment and hoardings from the
undesignated heritage asset, but these will be of a short
term and temporary nature.
f
5-21 (odd
numbers),
Queensway
Local
Views of construction equipment and hoardings from the
undesignated heritage asset, but these will be of a short
term and temporary nature.
Potential Operational Effects
16.5.10 The potential operational effects on the identified heritage assets during the operation of the
development are considered in the text below and Tables 16.10 and 16.11, according to the
methodology presented in Section 16.3.
16.5.11 The proposals include new college facilities for West Herts College in the northern part of the
site, and a new foodstore to the south, with associated car parking, petrol filling station and
improved access works. Proposals also include associated landscape design, including river
diversion and ecological improvements. The construction of large scale buildings close to
the site perimeter will introduce some permanent visual changes for the surrounding heritage
assets, but the degree of change that has already taken place within their settings, relating to
the comprehensive clearance of Alma Road and the Victorian waterworks (formerly located
in the northern and southern parts of the site respectively) and development of the College
and Civic Centre site in the 1960s and 1970s, reduces their sensitivity to further changes,
subject to the high quality of design of the proposed buildings.
16.5.12 The new College building at the north eastern corner of the site will sit in closer proximity to
The Bury (Grade II*, DHA2) and to the edge of the Hemel Hempstead High Street
Conservation Area (DHA39) than the existing buildings in this location, currently surrounded
by grassed lawns. The new building is also of a greater scale and massing in its design.
However, the thick band of yew trees along the northern edge of Queensway will contribute
to preserving the verdant setting of The Bury and the edge of the conservation area.
16.5.13 Heritage assets located on Queensway and at the southern end of the High Street will
experience some effects by the location of the College building at the junction of Queensway
and Marlowes, which will be a large building located in a more prominent location than the
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existing College buildings on this part of the site. This building will also have some effects
on heritage assets at the northern end of Marlowes.
16.5.14 The scheme proposes a new foodstore and associated car parking for the lower section of
the site, introducing a building of larger scale and proximity along Marlowes which will affect
the settings of the surrounding heritage assets to varying degrees. It should be noted that a
considerable amount of the car parking has been located within an undercroft, reducing the
visual effects of the scheme on the surrounding townscape.
16.5.15 St Mary’s Church (DHA32) sits on an elevated position in the landscape, to the north of the
site, allowing long distance views towards its tall spire from many different points in Hemel
Hempstead. Whilst development may have some effects on views, the church’s elevated
position in the landscape and considerable height of its spire will ensure that it will remain a
key focal point from both the Old Town and the New Town to the south.
16.5.16 Some undesignated assets are identified as experiencing some operational effects but the
significance of those effects is proportionate to their lower and local level of importance.
16.5.17 The potential operational effects upon the identified heritage assets are summarised in
Tables 16.10 and 16.11.
Table 16.10: Potential Operational Effects for Designated Heritage Assets
CgMs
ID
DHA1
DHA2
DHA3
DHA4
Document1
Description
51, Marlowes
The Bury
4, Queensway
Marlowes
Baptist Church
Importance
of Heritage
Asset
Explanation of Effect (Prior to Mitigation)
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing, also with some loss
of grassed lawns. These effects will be permanent but
the historic setting to the south of the listed building has
been considerably eroded by the erection of the College
in the 1960s, reducing its sensitivity to further changes in
this location.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already by the
construction of the Civic Centre in the 1960s, reducing its
sensitivity to further changes.
National
The new foodstore building will be a building of greater
scale, massing and closer proximity than the existing
buildings. Effects will be permanent but the historic
setting of the listed building has been considerably
eroded already by the construction of the Civic Centre in
the 1960s, reducing its sensitivity to further changes.
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CgMs
ID
Description
DHA5
Numbers 6
and 8, and
wrought iron
front railings,
Queensway
DHA6
DHA7
DHA8
DHA9
DHA1
0
DHA1
1
DHA1
2
DHA1
3
Document1
Old Marlowes
House
Little Marlowes
House
23 and 25,
Queensway
10, 12 and 14,
Queensway
27 and 29,
Queensway
57 and 59
Marlowes
16 and 18,
High Street
63 and 65,
Marlowes
Importance
of Heritage
Asset
Explanation of Effect (Prior to Mitigation)
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already, reducing its
sensitivity to further changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already, reducing its
sensitivity to further changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already, reducing its
sensitivity to further changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already, reducing its
sensitivity to further changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already by the
construction of the Civic Centre in the 1960s, reducing its
sensitivity to further changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
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CgMs
ID
DHA1
5
DHA1
6
DHA1
9
DHA2
2
DHA2
4
DHA2
6
Document1
Description
67, Marlowes
Lloyd's Bank
75 and 77,
Marlowes
Lockers
Cottage
79, Marlowes
81, Marlowes
Importance
of Heritage
Asset
Explanation of Effect (Prior to Mitigation)
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing with clear views from
the listed building towards the site. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded already, reducing its
sensitivity to further changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The north western corner of the site closest to this
building will include space for expansion of the college,
likely to comprise of buildings of a larger scale and
massing than those existing. Effects will be permanent
but views from the listed building are distant and its
historic setting has been considerably eroded already,
reducing its sensitivity to further changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
DHA2
7
83 and 85,
Marlowes
National
The south eastern corner of the site closest to this
building will comprise of car parking. Effects will be
permanent but the historic setting of this listed building
has been considerably eroded with the construction of the
1960s Civic Centre, reducing its sensitivity to further
changes.
DHA3
2
Church of St
Mary
National
Development may alter existing views of the church spire,
which is an important focal point in both the Old and New
Towns.
DHA3
9
Hemel
Hempstead
High Street
Conservation
Area
District
The new College building is of a greater scale, massing
and closer proximity than existing buildings, and there will
be some loss of grassed lawns.
Effects will be
permanent but the historic setting of the conservation
area has been considerably eroded already, reducing its
sensitivity to further changes.
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CgMs
ID
Description
DHA4
0
Hemel Water
Gardens
Registered
Park
Importance
of Heritage
Asset
Explanation of Effect (Prior to Mitigation)
National
Some changes to Leighton Buzzard Road, with
associated new signage and street furniture, but the road
does not contribute to the heritage significance of the
registered park and views of any changes to the road will
be limited to the park’s northern edge.
Table 16.11: Potential Operational Effects on Undesignated Heritage Assets
CgMs
ID
Description
Importance
of Heritage
Asset
b
7-33,
Marlowes
Local
c
Bury Lodge
Local
d
43, Marlowes
Local
e
37, Marlowes
Local
f
5-21 (odd
numbers),
Queensway
Local
Explanation of Effect (Prior to Mitigation)
The new College building and foodstore are of a greater
scale, mass and closer proximity than the existing
College buildings on site. Effects will be permanent but
the historic setting of these undesignated heritage assets
has been considerably eroded already with the erection
of the College and Civic Centre in the 1960s, reducing its
sensitivity to further changes.
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing, also with some loss
of grassed lawns. Effects will be permanent but the
historic setting to the south of the undesignated heritage
asset has been considerably eroded by the erection of
the College in the 1960s, reducing its sensitivity to further
changes in this location.
The new foodstore building will be a building of greater
scale, massing and closer proximity than the existing
buildings. Effects will be permanent but the historic
setting of this undesignated heritage asset has been
considerably eroded already by the construction of the
Civic Centre in the 1960s, reducing its sensitivity to
further changes.
The new foodstore building will be a building of greater
scale, massing and closer proximity than the existing
buildings. Effects will be permanent but the historic
setting of this undesignated heritage asset has been
considerably eroded already by the construction of the
Civic Centre in the 1960s, reducing its sensitivity to
further changes.
The new College building at the north eastern corner of
the site will be a building of greater scale, massing and
closer proximity than those existing. Effects will be
permanent but the historic setting of this undesignated
heritage asset has been considerably eroded already by
the College, erected in the 1960s, reducing its sensitivity
to further changes.
Mitigation Measures
Mitigation of Construction Effects
16.6.1
Document1
A Construction Environmental Management Plan (CEMP) has been produced to minimise
the effects of construction, including measures to screen the site during the construction
phase. Details of the CEMP may be found in Chapter 4 of the ES.
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16.6.2
Marlowes Methodists Church will be fully recorded, both internally and externally, to English
Heritage Level 3 standard as part of mitigating the effects of its demolition at construction
stage and a record deposited with the appropriate local archive.
16.6.3
The demolition of this building will also have some permanent effects on the setting of
Marlowes Baptist Church (DHA4), which sits in close proximity on Marlowes and which
together once formed a focal point of nineteenth century Non-Conformist worship in Hemel
Hempstead. These effects will be partly mitigated by the high quality of the proposed
replacement buildings, introducing elevations of interest which will encourage pedestrian
movement to the Old Town by their active frontages.
16.6.4
Proposed measures to mitigate the effects of construction on heritage assets (both
designated and undesignated) are listed below.
Table 16.12: Proposed Mitigation Measures for Constructional Effects Affecting Heritage Assets (Both Designated and
Undesignated)
CgMs
ID
Description
Proposed Mitigation
DHA4
Marlowes Baptist
Church
Replacement with a scheme of suitably high quality and full
recording of the chapel, prior to its demolition.
a
Marlowes
Methodist Chapel
Full internal and external building recording to English Heritage
Level 3 standard and deposition of record in local archives, as
agreed with DBC.
Mitigation of Operational Effects
16.6.5
The mitigation measures outlined in Table 16.13 below have been integral to the scheme
design to minimise any potential long term, permanent, operational effects upon the
surrounding heritage assets. Those assets, both designated and undesignated, identified as
experiencing no effects are therefore excluded from Table 16.13.
16.6.6
The potential operational effects of the proposed scheme will be mitigated by the high quality
design of the buildings, designed with architectural features and using varied building
materials that add interest to the streetscape, whilst also presenting active frontages that
encourage pedestrian movement between the Old Town and the New Town.
16.6.7
The proposed College building has been designed as a landmark building, befitting of its
position at the northern end of the site and the Gade Zone, taking advantage of the changes
in site levels (dropping 2.5m towards the river) which allows for the introduction of a building
that includes the required facilities for the College whilst maintaining a more domestic
external scale at the north eastern corner of the site, facing the junction between Queensway
and Marlowes. Its north facing elevation, having particular sensitivity to the heritage assets
in this vicinity, has been designed to create interest in the streetscape with a variety of
window sizes, shapes and depths and varying building materials that would further break up
the massing of the building when viewed between retained trees on the southern edge of
Queensway. The upper projecting storey will be rendered with a neutral appearance, with
facing brickwork to the ground floor and bronze colour cladding around large windows that
provide views into automotive workshops, exhibiting the educational facilities and providing
interest to passers-by.
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16.6.8
The proposed design and materials for the foodstore seek to introduce a modern and
contemporary building along the western side of Marlowes. The design is inspired by the
surrounding built environment, including a red brick ground floor with white render above,
which is deliberately reminiscent of the traditional building materials and different storey
treatments used in the High Street, such as at The White Hart Public House (DHA18).
Glazed sections in this elevation provide views to the interior and provide activity at ground
level, encouraging footfall along Marlowes and improving pedestrian links to the Old Town.
A canopied colonnade along the western elevation, wrapping around the foodstore, has also
been designed to break up the massing of, and provide articulation to the building. These
measures ensure that despite the increase in size from existing buildings on site, the
scheme is visually and contextually appropriate and would not jar inappropriately with the
surrounding urban and semi-urban context, to the south and north respectively.
16.6.9
The proposed scheme has been designed with integrated landscaping that will reduce the
effects of development, using a combination of appropriate perimeter planting and retention
of existing planting. Retention of trees along the southern edge of Queensway will provide
visual breaks that break up the massing of the College building behind, thereby reducing the
residual effects of development on The Bury (DHA2) and the Hemel Hempstead High Street
Conservation Area (DHA39). Perimeter planting along Marlowes, around the car parking
area, will also serve to reduce views into the site from the listed buildings there and reduce
the residual effects of development.
16.6.10 Tables 16.13 and 16.14 summarise measures to mitigate the operational effects of
development on identified heritage assets.
Table 16.13: Mitigation Proposals for Operational Effects on Designated Heritage Assets
CgMs
ID
DHA1
DHA2
DHA3
DHA4
Document1
Description
Proposed Mitigation
51, Marlowes
Views from the listed building towards the car park at the south
eastern corner of the site will be screened by trees along the
southern edge of Queensway as part of the landscaping strategy.
Where oblique views of the foodstore exist, these will feature the
canopied colonnade of the high quality building, which is a feature of
interest and which encourages pedestrian footfall by its active
frontage.
The Bury
Views from the listed building towards the new College building will
be partly screened by trees along the southern edge of Queensway,
retained as part of the proposed landscaping strategy. The building
is further designed with a north facing elevation of interest, with its
variety of window design, projecting upper floor and visually
appropriate building materials.
4, Queensway
The College building has been designed to present the appearance
of a two storey building at the junction and nearest the listed
building. The high quality of the proposed landmark building will
reduce the effects of development as an important entry point to the
Gade Zone.
Marlowes Baptist
Church
The foodstore will change the setting of this listed building by its
scale, massing and proximity along Marlowes. The effects of
development are partly mitigated by the high quality design
principles of the scheme, which uses render and different materials
to distinguish the different storeys, reflecting similar architectural
treatment for some historic buildings along the High Street.
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CgMs
ID
Description
Proposed Mitigation
DHA5
Numbers 6 and 8,
and wrought iron
front railings,
Queensway
Although the new College building will introduce some change to the
setting of this listed building, the high quality design of the building,
with lower height nearest the listed building, and will contribute to
mitigating the effects of development.
Old Marlowes
House
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park of the site will be screened by trees along the eastern
boundary as part of the landscaping element of proposals. Where
oblique views of the foodstore exist, these will feature the canopied
colonnade of the high quality building, which is a feature of interest
and which encourages pedestrian footfall by its active frontage.
DHA7
Little Marlowes
House
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
DHA8
23 and 25,
Queensway
Although the new College building will introduce some change to the
setting of this listed building, the high quality design of the building,
with lower height nearest the listed building, and will contribute to
mitigating the effects of development.
DHA9
10, 12 and 14,
Queensway
Although the new College building will introduce some change to the
setting of this listed building, the high quality design of the building,
with lower height nearest the listed building, and will contribute to
mitigating the effects of development.
DHA10
27 and 29,
Queensway
Although the new College building will introduce some change to the
setting of this listed building, the high quality design of the building,
with lower height nearest the listed building, and will contribute to
mitigating the effects of development.
57 and 59
Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
63 and 65,
Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
67, Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
Lloyd's Bank
The new College building will feature strongly in views from the
listed building and change its setting. The high quality design of the
building, with lower height nearest the listed building, will contribute
to mitigating the effects of development.
DHA6
DHA11
DHA13
DHA15
DHA16
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CgMs
ID
Description
Proposed Mitigation
DHA19
75 and 77,
Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
DHA22
Lockers Cottage
Views across the northern area of the site and the new buildings will
be screened by existing planting and planting introduced as part of
the landscaping strategy.
79, Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
81, Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
DHA27
83 and 85,
Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the listed building towards the proposed car
park here will be screened by trees along the eastern boundary as
part of the landscaping element of proposals. Where oblique views
of the foodstore exist, these will feature the canopied colonnade of
the high quality building, which is a feature of interest and which
encourages pedestrian footfall by its active frontage.
DHA32
Church Of St Mary
The proposed buildings have been designed to be of a suitable
height that will ensure that significant views of the church will not be
lost.
DHA39
Hemel Hempstead
High Street
Conservation Area
Retention of existing planting along the northern edge of the site
maintains some of the existing screening, although some views will
remain of the College building. The design and building materials of
the new building have been designed to respect the sensitivity of the
site next to the conservation area and partly mitigate the effects of
development, but they will still represent buildings in a closer
proximity than existing buildings on site.
DHA40
Hemel Water
Gardens
Registered Park
Works will be necessary to meet transport and access requirements,
visible in only limited views from the northern edge of the registered
par, which is already characterised by the surrounding road, with the
majority of the park having no views in this direction.
DHA24
DHA26
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Table 16.14: Mitigation for Operational Effects on Undesignated Heritage Assets
CgMs
ID
b
c
d
e
f
Description
Proposed Mitigation
7-33, Marlowes
The College building has been designed to present the appearance
of a two storey building at the junction and nearest the undesignated
heritage asset, where on the far side to the wests it rises to three
storeys. The high quality of the design will reduce the effects of
development.
Bury Lodge
Views from the undesignated heritage asset towards the new
College building will be partly screened by trees along the southern
edge of Queensway, retained as part of the proposed landscaping
strategy. The building is further designed to be of a suitable scale,
massing and visually appropriate building materials, particularly on
its north facing side.
43, Marlowes
Buildings have been located away from the south eastern corner of
the site and views from the undesignated heritage asset towards the
proposed car park here will be screened by trees along the eastern
boundary as part of the landscaping strategy.
37, Marlowes
The effects of development are partly mitigated by the design
principles of the foodstore, which uses render and different materials
to distinguish the different storeys, reflecting similar architectural
treatment for some historic buildings along the High Street.
5 - 21, Queensway
The College building has been designed to present the appearance
of a two storey building at the junction and nearest the undesignated
heritage asset, where on the far side to the wests it rises to three
storeys. The high quality of the design will reduce the effects of
development.
Residual Effects
16.7.1
Tables 16.15, 16.16 and 16.17 present the significance of likely residual effects of the
development from its completion in 2014 or early 2015, taking into account the mitigation
measures that exist as integral elements of the scheme’s design.
16.7.2
It is considered that the degree of change that has already taken place on this site, after the
complete clearance of the residential street of Alma Road and its redevelopment in the
1960s, is such that further redevelopment would have mostly limited residual effects on the
settings and heritage significance of identified heritage assets within the 250m study area.
16.7.3
Residual effects of construction will affect the Marlowes Methodists Church (a), which will be
demolished as part of the development. The building would experience direct and
permanent adverse effects, but the significance of these effects is reduced by the modest
heritage significance of the undesignated heritage asset and by the full internal and external
recording of the building to English Heritage Level 3.
16.7.4
Demolition of Marlowes Methodists church would also have permanent adverse, but indirect,
constructional effects on the setting of the Marlowes Baptist Church (Grade II, DHA6)
nearby, which together once represented a focal point for nineteenth century NonConformism in Hemel Hempstead.
16.7.5
The proposed College building to the north east of the site will have some adverse residual
operational effects on the surrounding heritage assets in this vicinity by virtue of its scale and
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closer proximity to the road junction than existing buildings on site. The increased proximity
of the proposed building introduces some mostly minor and indirect adverse effects within
the setting of some heritage assets, increasing the urban character of this sub-urban area,
although these are partly mitigated by the high quality of its design as a new landmark
building in the Gade Zone.
16.7.6
Of particular note regarding the northern part of the site is The Bury (Grade II* listed, DHA2)
and the Hemel Hempstead High Street Conservation Area (DHA39). Whilst the proposed
buildings would be located in closer proximity to heritage assets around the northern and
eastern edges of the site, the existing thick band of Yew trees to the north of Queensway will
remain unaffected by development and will supplement screening provided to the south of
the road by trees retained as part of the landscaping strategy, thereby reducing effects on
the setting of The Bury. The combined presence of trees along the northern and southern
edges of Queensway further serve to maintain a sense of the formerly verdant edge to the
Hemel Hempstead High Street Conservation Area.
16.7.7
The Marlowes Baptist Church (DHA6) has clear views west across the site and would
experience some residual operational effects by the placement of large buildings in closer
proximity than the existing buildings on site. These effects are partly mitigated however, by
the high quality design of the foodstore elevation on Marlowes and the interest added by the
colonnade and contrasting building materials between storeys.
16.7.8
Towards the south eastern corner of the site the set back of proposed buildings from the site
boundary and the introduction of appropriate landscaping will reduce the residual operational
effects of the scheme to a negligible level. Whilst some oblique views may remain of the
foodstore from heritage assets on Marlowes, it is considered that the high quality of the
building design limits the potential adverse effects on the settings of heritage assets in this
vicinity.
Table 16.15: Residual Construction Effects for Designated and Undesignated Heritage Assets
CgMs
ID
Document1
Description
DHA4
Marlowes
Baptist
Church
a
Marlowes
Methodist
Chapel
Importance
of Heritage
Asset
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
National
Minor
adverse,
indirect
Permanent loss of
Marlowes Methodists
Church within its setting
in an area of town
associated with NonConformist places of
worship, mitigated by full
building recording that
allows a continued
understanding of this
relationship between the
buildings.
Moderate
adverse
Local
Major
adverse,
direct
Permanent removal of
building. Residual effects
are reduced by full
building recording early in
the Construction Phase.
Minor adverse
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Table 16.16: Residual Operational Effects for Designated Heritage Assets
CgMs
ID
DHA1
DHA2
DHA3
DHA4
DHA5
Document1
Description
51,
Marlowes
The Bury
4,
Queensway
Marlowes
Baptist
Church
Numbers 6
and 8, and
wrought iron
front railings,
Queensway
Importance
of Heritage
Asset
National
National
National
National
National
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Minor
adverse
The College building will
sit in closer proximity
than existing buildings to
this highly graded listed
building (Grade II*), with
the loss of grassed
lawns, but views of the
high quality College
building will be limited
and partly screened by
trees along the northern
and southern edges of
Queensway.
Moderate
adverse
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Minor
adverse/ Not
significant
The foodstore will sit
within closer proximity
than existing buildings,
but the high quality of the
design will reduce the
effects of development in
an area that has already
seen considerable
change in the 1960s.
Minor adverse
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
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CgMs
ID
DHA6
DHA7
DHA8
DHA9
DHA1
0
DHA1
1
Document1
Description
Old
Marlowes
House
Little
Marlowes
House
23 and 25,
Queensway
10, 12 and
14,
Queensway
27 and 29,
Queensway
57 and 59
Marlowes
Importance
of Heritage
Asset
National
National
National
National
National
National
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
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CgMs
ID
DHA1
3
DHA1
5
DHA1
6
63 and 65,
Marlowes
67,
Marlowes
Lloyd's Bank
DHA1
9
75 and 77,
Marlowes
DHA2
2
Lockers
Cottage
DHA2
4
DHA2
6
Document1
Description
79,
Marlowes
81,
Marlowes
Importance
of Heritage
Asset
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Minor
adverse/ Not
significant
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
National
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
National
Not
Significant
Distant views towards
site are limited by
proposed landscaping
and mitigated by high
quality of design.
Not significant
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
National
National
National
National
National
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CgMs
ID
DHA2
7
83 and 85,
Marlowes
DHA3
2
Church Of St
Mary
DHA3
9
DHA4
0
Document1
Description
Hemel
Hempstead
High Street
Conservatio
n Area
Hemel Water
Gardens
Registered
Park
Importance
of Heritage
Asset
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
National
Not
Significant
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site and by
high quality of new
buildings.
Not significant
National
Not
Significant
Long distance views of
church spire from the
New Town will not be
affected by proposals.
Not significant
Moderate
adverse,
indirect
The College building will
sit in closer proximity
than existing buildings,
and will be of a greater
scale than existing
buildings, but its high
quality of design and the
degree of alteration that
has taken place in this
area help to mitigate the
magnitude of effects.
Minor adverse
Not
Significant
Works to improve access
from Leighton Road are
governed by transport
requirements and will be
visible from only the
northern edge of the
park, which is already
characterised by the
surrounding road.
Not significant
District
National
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Table 16.17 Residual Operational Effects for Undesignated Heritage Assets
CgMs
ID
b
c
d
e
f
Document1
Description
7-33,
Marlowes
Bury Lodge
43,
Marlowes
37,
Marlowes
5 - 21,
Queensway
Importance
of Heritage
Asset
Magnitude
and Nature
of Effect
Effect
Significance
of Effects
Minor
adverse,
indirect
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Local
Minor
adverse,
indirect
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Minor adverse
Local
Minor
adverse,
indirect
Views towards site are
mitigated by perimeter
landscaping around the
car park in the south east
corner of the site.
Not significant
Minor
adverse,
indirect
The foodstore will sit
within closer proximity
than existing buildings,
but the high quality of the
design will reduce the
effects of development in
an area that has already
seen considerable
change in the 1960s.
Minor adverse
Minor
adverse,
indirect
The College building will
sit in closer proximity
than existing buildings,
but the high quality of
design and the degree of
change that has already
occurred in this area
reduces the magnitude of
effects on this heritage
asset.
Not significant
Local
Local
Local
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Summary
16.8.1
After an assessment of the baseline conditions as presented in Appendix K.1, the methods
used to define the potential effects on built heritage assets associated with the proposed
scheme are as follows:

An evaluation of the importance of built heritage assets (based on existing designations
and professional judgement where assets have no formal designation);

Prediction of the nature and magnitude of the likely effects upon the significance of
known or potential buried heritage assets;

Determination of what mitigation measures are required during the design and
construction of operational lifetime of the Proposed Scheme in order to mitigate any
adverse effects; and

Quantification of any residual effects that might remain after mitigation measures are
applied.
16.8.1
It has been identified that the proposed scheme will involve the clearance of a collection of
unremarkable 1960s buildings, typical of their period, but not good exemplars relating to civic
buildings or educational uses. The Marlowes Methodists Church will also be demolished as
part of the scheme after it has been fully recorded both internally and externally, and the
record deposited in an appropriate archive, to be agreed with DBC. In addition to the
identified residual constructional effects on the undesignated heritage asset itself, this
demolition will also have some residual constructional effects on the setting of Marlowes
Baptist Church (DHA4), with which it shared a historic context. However, as the Methodists
Church is of no more than local value impacts are identified as of minor adverse significance
and impacts on the Baptist Church are of moderate adverse significance.
16.8.2
A new building for the West Herts College will be erected at the north eastern corner of the
site, which will introduce activity and architectural interest to this corner, creating a landmark
corner building. This will introduce some residual operational effects for the heritage assets
within the vicinity, in particular The Bury (DHA2), but these effects are mitigated by the
landscaping strategy which retains a number of existing trees along the southern edge of
Queensway and by the high quality design of the proposed building, presenting elevations of
interest and activity that would benefit the quality of the streetscape. The residual impact will
be of moderate adverse significance.
16.8.3
Also experiencing some minor adverse residual operational effects relating to the proposed
West Herts College Building are the Hemel Hempstead High Street Conservation Area
(DHA39), 4 Queensway (DHA3), 6 and 8 Queensway (DHA5), 23 and 25 Queensway
(DHA8), 10, 12 and 14 Queensway (DHA9), 27 and 29, Queensway (DHA10), Lloyds Bank
(DHA16), 7-33 Marlowes (undesignated heritage asset b), Bury Lodge (undesignated
heritage asset c) and 37 Marlowes (undesignated heritage asset e), but these effects are
mitigated by the high quality design of the proposed building. This northern eastern area of
the site has also undergone considerable change in the 1960s and 1970s, reducing its
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contribution to the settings of the heritage assets and reducing its sensitivity to further
change.
16.8.4
A new foodstore is proposed along the western edge of Marlowes, which will have some
residual operational effects for assets including the Marlowes Baptist Church (DHA4) and 37,
Marlowes (undesignated heritage asset). These effects are mitigated by the high quality
design of the proposed building which will introduce an active frontage to Marlowes and
encourage footfall between the Old Town and the New Town.
16.8.5
Towards the south eastern corner of the site the set back of proposed buildings from the site
boundary and the introduction of appropriate landscaping around proposed car parking
areas will reduce the residual operational effects of the scheme to a negligible level. Whilst
some oblique views may remain of the foodstore from heritage assets on Marlowes, it is
considered that the high quality of the building design limits the potential adverse effects on
the settings of heritage assets in this vicinity.
References
Document1

National Heritage List for England (online source, accessed 17.01.13)

Hertfordshire HER (online source, accessed 17.01.13)

Dacorum Borough Council, 2012, Hemel Hempstead Heritage Improvement Study

Dacorum Borough Council, 2012, Hemel Hempstead Old Town Character Appraisal
and Management Proposals

Dacorum Borough Council, 2013, Hemel Hempstead Town Centre Masterplan

English Heritage, 2008, Conservation Principles

English Heritage, 2011, Seeing the History in the View

English Heritage, 2011, The Setting of Heritage Assets

Victoria County History, 1908, Hertfordshire Volume 2 (online source, accessed
17.01.13)
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17
Summary & Impact Interactions
Introduction
17.1.1
Environmental effects can result from incremental changes caused by the interactions
between effects resulting from a project. For the purpose of this assessment, the
interactions between effects associated with the proposed development are defined as
“combined effects”.
17.1.2
The direct and indirect effects of the proposed development have been assessed within the
relevant topic chapters of the ES prepared by suitable technical specialists. Environmental
effects are assessed relative to the topic under consideration. This approach can lead to the
interaction of effects being reported in separate chapters but the collective effect on the
same environmental resource(s) not being considered.
17.1.3
In response this chapter, prepared by Peter Brett Associates LLP, summarises the principal
findings of each topic chapter of the ES to enable assessment of the potential for impact
interactions. This chapter also provides a summary of the environmental effects identified
throughout the ES and allows a judgement to be made of the overall effect of the proposed
development during construction and operation.
Methodology
17.2.1
The assessment methodology for combined effects involves the identification of impact
interactions associated with both the construction and operational phases of the proposed
development upon one or more environmental resources. This is undertaken using a
qualitative appraisal process.
17.2.2
This approach has been used by PBA for numerous EIAs and draws upon the following
guidance:
17.2.3
Document1

Institute of Environmental Management & Assessment, (2004), Guidelines for
Environmental Impact Assessment, IEMA

Hyder, (1999), Final Report on the Study on the Assessment of Indirect and Cumulative
Impacts, as well as Impact Interactions within the Environmental Impact Assessment
(EIA) Process NE80328/D3/2, European Commission Directorate General XI,
Environment, Nuclear Safety and Civil Protection

Mitigation measures are identified in each of the topic chapters, and have been used to
inform the assessment presented in this chapter.
The assessment of the significance of effects has been based on the generic significance
criteria provided in Table 5.1.
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Construction Effects
17.4.1
The most sensitive receptors to potential combined effects during construction are local
residents and users of the site.
17.4.2
The site is surrounded by residential development on two sides and it is these nearby
residents that are likely to be most affected by construction. In particular, it is likely that
residents immediately adjacent to the site (e.g. on Bury Road, Leighton Buzzard Road and
on Marlowes)
17.4.3
The impacts of construction on local residents will primarily come from visual intrusion and
change to the character of the area. Assuming that local residents will be subject to the
worse case effects identified in each of the topic chapters, then the following effects could be
experienced:

Moderate adverse visual impacts on views from the north, including from The Bury,
Gadebridge Park (Eastern Entrance); and views from Old Marlowes House to the south
east.

Many residents would experience minor-moderate visual impacts at construction,
including residents on Bury Road, people using the Leighton Buzzard Road/Riverside
Walk, residents on Warners End Road, and at the western entrance to Gaderidge Park.

Construction traffic around the site is also likely to create a minor adverse impact on the
local road network.

Noise and vibration from construction is also likely to have a moderate adverse impact
on local residents.
17.4.4
It should be noted that these construction effects will be temporary, with constructing
currently programmed to last approximately a year. They will also be intermittent, varying
due to the nature of the construction works being undertaken at a particular period and for
part of the time are likely to be much less significant than identified above, or not occur at all.
17.4.5
Local residents may also experience a moderate beneficial effect in relation to construction
employment.
17.4.6
It is therefore considered that the construction of the proposed development will have a
moderate adverse effect on local residents. This effect will generally reduce in significance
with distance from the site.
17.4.7
Users of the town centre will be subject to many of the same effects as local residents.
However, they will be subject to these effects less frequently and for shorter periods. As
such they are less sensitive receptors. It is therefore considered that users of the town
centre will be subject to a minor adverse effect during the construction period.
17.4.8
The River Gade and the aquifer also will experience impacts from various sources at
construction, and the following effects could be experienced:
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17.4.9

There is the potential for minor adverse impacts on the water quality of the River Gade
related to the risks of construction.

As a result of the loss of riverine and riparian habitats due to the diversion of the River
Gade there may be an impact of moderate adverse significance, although this is
temporary until the new river becomes fully established.
The other significant construction effects are:

There could be a moderate to major adverse impact on the aquifer that underlies the
site, this is due to the small risk of water quality impacts on this very highly important
receptor.

There will be moderate adverse impacts on the listed Marlowes Baptist Church;

There will be minor adverse impacts on the Marlowes Methodists Church that is to be
demolished following full recording.

During construction the character of the site and nearby areas will change. The site
itself will experience moderate adverse impacts as will the Gade Zone and the character
of the Hemel Old Town, just north of the site.

There will also be impacts of moderate adverse significance due to the loss of mature
trees on the site, although this too will reduce with time as new trees become
established.
Operation Effects
17.5.1
While the majority of the construction effects are adverse, many of the environmental effects
of the operation are more mixed. Operational effects are also typically permanent rather
than temporary.
17.5.2
Again local residents are likely to be most significantly affected by the proposed
development, they will:
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
The socio-economic assessment identifies that there will be moderate to major beneficial
impacts for education services created through the improved West Herts College
facilities. The college and the foodstore would also have minor beneficial impacts
related to improving vocational training and local labour market effects, social and
community effects. The foodstore would have minor beneficial effects though the
creation of new jobs. The relocation of the Council will also have minor benefits for the
services they offer.

The visual impact of the development is likely to have overall beneficial impacts on views
of the site for local residents. Impacts will be particularly beneficial in the longer term
when the proposed landscaping has time to become established, with visual impacts
from most of the identified receptors being of moderate beneficial effect. In the short
there will be moderate-major adverse impacts on views from 100 Bury Road while
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landscaping is becoming established. This improves over time to a moderate beneficial
impact as the trees and bushes around the River Gade become established. Also in the
longer term some adverse impacts will remain, such as the views from Old Lloyds Bank,
where the built character will permanently change.

New pedestrian and cycle links through the site, including an attractive riverside walk,
will improve connectivity for local residents and will have minor beneficial effects.

There will be minor adverse impacts on local residents from the odour from the kitchens
that will be part of the foodstore.
17.5.3
As these effects are permanent, the proposed development should have a moderate
beneficial effect on local residents. This effect will reduce in significance with distance from
the site.
17.5.4
Users of the town centre, and therefore it is reasonable to say people who live and/or work in
Hemel Hempstead, will receive many of the effects identified above. The level of effect is
likely to depend on their proximity to the site, and therefore overall is considered to be a
minor beneficial effect.
17.5.5
Other significant effects of the development will include:
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
Moderate beneficial effects on the town centre and retail spend. Overall there are
anticipated to be minor to moderate beneficial effects on regeneration of Hemel
Hempstead town centre from the proposed development.

The character of the area may also be affected by the proposed development. Once
landscaping has become established the impact will be mainly beneficial, with moderate
beneficial impacts on the site as a whole. However, as the proposed development is
more dense than the current development and will be built up closer to the site
boundaries there will be minor adverse impacts on many of the listed buildings and
buildings of local importance that surround the site, and moderate adverse on Grade II*
listed building ‘The Bury’.

It is likely that the water quality of the River Gade and the underlying aquifer will
experience minor to moderate beneficial effects due the site becoming better
management of surface water drainage. However, during early operational years as
vegetation becomes established there will moderate adverse effects on the River Gade,
which will reduce over time.

There may be minor beneficial effects on wildlife and ecology, including bats, nesting
birds, and other priority species and through the establishment of new hedgerow.
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18
Glossary
AADT
AMEC
AOD
AQAP
AQMA
AS
BaP
BAP
BFI
BgL
BGS
BHS
BIS
BREEAM
BS
BSI
CDMR
CEAP
CEMP
CIHT
CIRIA
CLG
COSHH
CS
DBC
DCLG
DEFRA
DMRB
DoT
DTM
DWS
EA
EC
EFT
EIA
EPUK
EQS
FRA
FTEs
FWMA
FZ
GEA
GFA
GFE
GIA
GLA
GLVIA
GZPPS
HALS
HCC
HCC HER
HCC HEU
HDV
Document1
Annual Average Daily Traffic
AMEC E&I
Above Ordnance Datum
Air Quality Action Plan
Air Quality Management Area
Archaeological Solutions Ltd
Benzo{a}pyrene
Biodiversity Action Plan
Baseflow Index
Below Ground Level
British Geological Survey
British Hydrology Society
Department of Business, Innovation and Skills
Building Research Establishment Environmental Assessment Method
British Standards
British Standards Institution
Construction (Design and Management) Regulations
Construction Environmental Action Plan
Construction Environmental Management Plan
Chartered Institute of Highways and Transport
Construction Industry Research and Information Association
Communities and Local Government
Control of Substances Hazardous to Health
Core Strategy
Dacorum Borough Council
Department for Communities and Local Government
Department for Environment, Food and Rural Affairs
Design Manual for Roads and Bridges
Department of Transport
Digital Terrain Model
Drinking Water Standards
Environment Agency
European Commission
Emission Factor Toolkit
Environmental Impact Assessment
Environmental Protection UK
Environmental Quality Standards
Flood Risk Assessment
Full Time Equivalent Jobs
Flood and Water Management Act
Flood Zone
Gross External Area
Gross Floor Area
General Further Education
Gross Internal Area
The Greater London Authority
Guidelines for Landscape and Visual Impact Assessment
Gade Zone Policy Planning Statement
Hertfordshire Archives and Local studies
Hertfordshire County Council
Hertfordshire County Council Historic Environment Record
Hertfordshire County Council Historic Environment Unit
Heavy Duty Vehicle: a vehicle with a gross vehicles weight greater than 3.5 tonnes,
for instance HGVs and buses.
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HMRC
HV
IAQM
IEEM
IEMA
IPPC
JCAs
LAQM
LDF
LDV
LEP
LI
LNR
LPA
LTP
LV
LWS
Mannings n
NAQOs
NCAs
NEETs
NERC
NGR
NHBC
NO2
NOx
NPPF
NPSE
NRFA
ODL
OJEU
ONS
PAH
PCU
PFS
PM10
PM2.5
PPE
PPG
PPG
PPS
RBMP
RFC
SAB
SAC
SFRA
SI
SPD
SPZ
SRAP
SSEW
SSSI
SuDS
SW
TA
TCFMP
Document1
Her Majesty’s Revenue and Customs
High Voltage
Institute of Air Quality Management
Institute of Ecology and Environmental Management
Institute of Environmental Management and Assessment
Integrated Pollution Prevention and Control
Joint Character Areas
Local Air Quality Management
Local Development Framework
Light Duty Vehicle
Local Enterprise Partnership
Landscape Institute
Local Nature Reserve
Local Planning Authorities
Local Transport Plan
Low Voltage
Local Wildlife Site
an empirical formula estimating channel flow driven by gravity
National Air Quality Objectives
National Character Areas
Not in Education, Employment or Training
Natural Environment and Rural Communities
National Grid Reference
National House Building Council
Nitrogen Dioxide
Nitrogen Oxides, generally considered to be Nitric Oxide and Nitrogen Dioxide
National Planning Policy Framework
Noise Policy Statement for England
National River Flow Archive
Optimisation Developments Ltd
Official Journal of the European Union
Office for National Statistics
Polyaromatic hydrocarbons
Passenger Car Unit
Petrol Filling Station
Small Airborne Particles less that 10µm in diameter
Small Airborne Particles less than 2.5µm in diameter
Personal Protective Equipment
Planning Policy Guidance
Pollution Prevention Guidance
Planning Policy Statement
River Basin Management Plans
Ratio Flow to Capacity (calculated as the traffic demand divided by the junction
capacity, when the RFC is 100%, it means that the junction is fully used)
SuDS Approval Body
Special Area of Conservation
Strategic Flood Risk Assessment
Statutory Instrument
Supplementary Planning Document
Source Protection Zone
Sustainable River Abstraction Programme
Soil Survey of England and Wales
Site of Special Scientific Interest
Sustainable Drainage System
Surface Water
Transport Assessment
Thames Catchment Flood Management Plan
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TPH
TPO
TRBMP
TRL
TVIA
WFD
WHC
WHO
WPZ
Document1
Total Petroleum Hydrocarbons
Tree Preservation Order
Thames River Basin Management Plan
Transport Research Laboratory
Townscape and Visual Impact Assessment
Water Framework Directive
West Herts College
World Health Organisation
Water Protection Zone
383