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North Norfolk Sandscaping
Feasibility Study
The Crown Estate
29 January 2015
Draft Report
PB2327
HASKONINGDHV UK LIMITED
RIVERS, DELTAS & COASTS
Rightwell House
Bretton
Peterborough PE3 8DW
United Kingdom
+44 1733 334455
Telephone
+44 1733 262243
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info@peterborough.royalhaskoning.com
www.royalhaskoningdhv.com
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North Norfolk Sandscaping
Feasibility Study
Document short title
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N Norfolk Sandscaping Feasibility
Draft Report
29 January 2015
North Norfolk Sandscaping Feasibility
PB2327
The Crown Estate
Reference
PB2327/R/301903/PBor
Drafted by
Amy Savage, David Brew, Theresa Redding
Checked by
Date/initials check
Approved by
Date/initials approval
Greg Guthrie
27/01/2015
JGLG
Jaap Flikweert
28/01/2015
JJF
A company of Royal HaskoningDHV
SUMMARY
TO BE COMPLETED FOR FINAL VERSION OF REPORT
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CONTENTS
Page
1
INTRODUCTION
1.1
Background
1.1.1
This Project
1.1.2
Introduction to Sandscaping
1.1.3
The UK Context
1.2
Potential for Sandscaping in North Norfolk
1.3
Study Partners
1.4
Feasibility Study Objectives
1.5
Report Layout
1
1
1
1
1
2
3
3
3
2
THE SANDSCAPING APPROACH
2.1
Introduction
2.2
The Dutch Sand Engine
4
4
4
3
THE STUDY AREA
3.1
Location
3.1.1
Key features of the coastline
3.1.2
Physical Conditions
3.1.3
Geology and Geomorphology
3.1.4
Analysis of SCAPE model results
3.1.5
Beach Behaviour
3.1.6
Present Management of the Coast
3.2
Natural Environment Constraints & Opportunities
3.3
Socio-Economic Considerations
3.4
Potential for Sandscaping
6
6
6
7
8
10
13
14
16
19
19
4
OBJECTIVES FOR SANDSCAPING
4.1
Functional Performance Objectives
4.2
Opportunity Benefits
21
21
21
5
DESIGN CRITERIA AND ASSUMPTIONS
5.1
Effective Life of Scheme
5.2
Risk Management
5.2.1
Risk Management - Bacton Gas Terminal Complex
5.2.2
Risk Management - Bacton to Walcott frontage
5.2.3
Risk Management – Mundesley
5.2.4
Risk Management - Ostend to Eccles
5.2.5
Risk Management - Eccles to Winterton
5.3
Coastal Processes
5.3.1
Volume of Sediment
5.3.2
Nourishment Location, Plan Shape and Profile
5.4
Environmental Constraints
5.5
Summary of Design Criteria and Design Assumptions
22
22
22
22
24
25
25
26
26
26
27
28
29
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6
BENEFITS ASSESSMENT
31
6.1
Approach
31
6.2
Coastal Management Scenarios and Impacts
31
6.3
Flood and Coastal Erosion Risk Management Benefits
33
6.3.1
Summary of Baseline Data and Information
33
6.3.2
Damages and Costs Associated with Policy Units 6.05 to 6.07 (Cromer to
Mundesley)
33
6.3.3
Damages and Costs Associated with Policy Unit 6.08 (Mundesley)
34
6.3.4
Damages and Costs for Policy Unit 6.10 (Bacton Gas Terminal)
34
6.3.5
Damages and Costs for Policy Unit 6.11 (Bacton, Walcott and Ostend)
35
6.3.6
Damages and Costs for Policy Unit 6.12 (Ostend to Eccles)
36
6.3.7
Damages and Costs Associated with Eccles to Winterton Frontage
36
6.3.8
Summary of Flood and Coastal Erosion Risk Management Benefits and
Costs
37
6.4
Amenity Benefits
42
6.4.1
Summary of Data and Information (Visitor Numbers and Spend)
42
6.4.2
Beach and Car Park Use
44
6.4.3
Caravan Park Occupancy
44
6.4.4
Amenity Value based on Multi-Coloured Manual Method
45
6.4.5
Assumptions for this study
46
6.5
Natural Environment Benefits
47
6.6
Other Social Impacts
47
6.7
Creating Opportunity
49
6.7.1
Alternative Approach to Adaptive Coastal Management
49
6.7.2
Potential Growth in Tourism, Associated Businesses and Employment
49
6.7.3
Residential Property Value and Development Potential
50
6.8
Benefit Cost Ratios
51
7
CONCLUSIONS AND RECOMMENDATIONS
7.1
Conclusions
7.2
Uncertainties
7.3
Recommendations for Next Steps
53
53
54
55
8
REFERENCES
57
APPENDIX A - INTRODUCTION TO THE NORTH NORFOLK COASTAL ENVIRONMENT
APPENDIX B – EXTRACT FROM SHORELINE MANAGEMENT PLAN – BASELINE
PROCESSES UNDERSTANDING
APPENDIX C – ANALYSIS OF SCAPE MODELLING
APPENDIX D – BEACH PROFILES
APPENDIX E - NATURAL ENVIRONMENT CONSTRAINTS & OPPORTUNITIES
APPENDIX F – COSTS ASSESSMENT
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1
INTRODUCTION
1.1
Background
1.1.1
This Project
Royal HaskoningDHV (RHDHV) has been commissioned by The Crown Estate to
develop a feasibility study for the application of a relatively new and innovative approach
to coastal management on the Norfolk coastline. The approach is labelled ‘Sandscaping’
and in summary is a large scale beach nourishment that makes active use of natural
processes to feed and redistribute sediment to a coastline, to meet flood and coastal
erosion management objectives, while at the same time generating additional social,
economic and environmental benefits.
1.1.2
Introduction to Sandscaping
The Sandscaping approach has been pioneered by the Netherlands (where it is called
the ‘Sand Engine’) as part of the country’s ‘Building with Nature’ innovation programme.
This programme, which has been embraced by a significant consortium of government
and other organisations aims to integrate infrastructure, society and nature in new forms
of engineering to achieve sustainability, particularly within the water environment.
The most prominent case study of a fully implemented Sand Engine in the Netherlands
is the Delfland Sand Engine. Constructed in 2011, the scheme has already generated
significant benefits in terms of:
•
•
•
•
Recreation through the creation of new land with new opportunities;
Efficiency, through economies of scale effects;
Environmental enhancement in the nourished area and the sediment extraction
area;
As well as delivering Flood and Coastal Erosion Risk Management (FCERM).
Section 2.2 gives some further details of the Delfland Sand Engine.
There is a large potential variation in form and layout of a ‘Sand Engine’, depending on
the location that is being considered. Previous Feasibility Studies for north Wales,
Lincolnshire and Suffolk have required different approaches to account for locationspecific factors (e.g. the sand/shingle mix beaches in Suffolk).
1.1.3
The UK Context
There is an increasing interest in the UK in Sandscaping approaches as a real
opportunity in terms of delivery of effective FCERM. This opportunity is strengthened by
recent changes to the way FCERM projects are funded in this country; projects are likely
to require external funding to be feasible, and there is an increasing onus for schemes to
deliver additional benefits above and beyond traditional FCERM objectives. The Crown
Estate recognise their key role in this and have been keen to support and develop the
concept.
The Crown Estate has a direct interest in the Sandscaping approach through their roles
both as licenser of extraction sites (which would provide sediment for Sandscaping
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projects) and as an owner of large parts of the coastline (which Sandscaping projects
could enhance). The approach however also meets The Crown Estate’s core objectives of
‘Integrity, Commercialism and Stewardship’.
This initiative has already led to three technical feasibility studies being undertaken for
locations in the UK. With The Crown Estate, RHDHV have developed the concept for
Conwy in north Wales (2011), for the Lincolnshire coast (2013) and for the Suffolk coast
(2013). Each project has generated an interest at a number of levels, including local
government and amongst the Environment Agency. However, given the significant
investment involved and the inherent complexities in developing a more integrated,
broader scale approach, the opportunities that can be delivered by Sandscaping can be
lost within a more traditional project appraisal driven by short term or immediate need.
The aim of this study and report is to examine the potential benefits, recognising the
uncertainties, and, in outline, the costs involved so as to provide a more level playing
field in comparison to more traditional approaches to defence and coastal management.
1.2
Potential for Sandscaping in North Norfolk
Previous work by Royal HaskoningDHV on behalf of The Crown Estate has identified the
North Norfolk coast as potentially suitable for Sandscaping.
The importance of sediment to the North Norfolk coast is highlighted in the Shoreline
Management Plan1 (SMP2) for the area. This SMP document sets out a high level
approach to sustainable management of flood and coastal erosion risk. The SMP2
builds upon the concept of a functioning of the coast, and its policies take account of
social and environmental factors to ensure that these influence and drive our approach
to management. In many ways and in many areas, it is sediment processes that have
determined the SMP2 policies.
While it is strongly understood that the natural features of the Norfolk coast have their
own particularities, the nesses, such as Winterton Ness, the spits, more evident along the
north coast of Norfolk, and the subtle changes in coastal orientation along the north east
coast are characteristic features of the North Norfolk coast, influencing, regulating and
supplying sediment over larger areas in a natural way. The nearshore and offshore zones
are characterised by shoals and sandbanks, which again influence wave and sediment
transport processes. In many ways, these features demonstrate the basic Sandscaping
concept in introducing a sediment feature which is able to influence the way in which the
coast functions in relation to the needs of coastal management. This feasibility study
considers these natural features and processes and builds upon this concept, looking at
ways in which this naturally functioning system can be enhanced.
The Sandscaping concept opens up different possibilities for delivering the intent of the
SMP2; changing the timescales of policies and the attitude towards adaptation, while
still building upon the same underlying understanding and principles for sustainable
management.
1
Kelling to Lowestoft Ness Shoreline Management Plan, North Norfolk District Council, 2012
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1.3
Study Partners
This Feasibility Study has been commissioned by The Crown Estate, with financial
contribution from North Norfolk District Council. The development of the study has
involved discussion with North Norfolk District Council, the Environment Agency and
Natural England, who have provided information to the study and have commented on
the report. The Crown Estate wish to acknowledge the support these stakeholder
organisations have provided.
1.4
Feasibility Study Objectives
This technical Feasibility Study is being undertaken to investigate the viability of
undertaking large-scale beach nourishment (Sandscaping) along part of the North
Norfolk coast between Mundesley and Walcott. It is not intended that the study will
determine the location and shape of a Sandscaping scheme in any detail.
The technical analysis will assess the quantity of Sandscaping nourishment required to
achieve flood and coastal risk management outcomes at least equivalent to the current
Shoreline Management Plan policy for the area. The study will also identify where such
an approach to coastal management will enable additional benefits to be realised, in
terms of enabling an alternative approach to coastal protection, enhancing the natural
environment and providing socio-economic benefits such as improved quality of life,
additional amenity value and potential for inward investment in the area. Any constraints
on the implementation of Sandscaping will be identified.
1.5
Report Layout
•
Section 2 provides more detail about the overall Sandscaping approach, using the
Delfland Sand Engine as a case study.
•
Section 3 introduces the study area, the North Norfolk coast between Cromer and
Winterton, including its main physical, environmental and social characteristics.
•
Section 4 defines the objectives for a Sandscaping project for the North Norfolk coast,
based on the Delftland Sand Engine case study and the particular characteristics of the
study area.
•
Section 5 explores the technical feasibility of Sandscaping for this area, considering
wave and tidal conditions, coastal geomorphology, local beach profile variations, and
reviewing previous SCAPE model results. This is supported by a separate Appendix C,
providing further analysis of existing SCAPE results.
•
Section 6 defines the design criteria and assumptions applied in the assessment of the
viability of a Sandscaping project for North Norfolk, based on the characteristics of the
study area and the project objectives. .
•
Section 7 assesses the benefits that could be derived if Sandscaping was implemented,
both quantitatively and qualitatively, based on the previously defined criteria.
•
Section 8 provides conclusions and recommendations, including identification of
uncertainties and setting out the potential way forward for progressing towards
implementation of a Sandscaping scheme.
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2
THE SANDSCAPING APPROACH
2.1
Introduction
It is widely accepted that a healthy beach is one of the most effective forms of coastal
defence. As long as the beach has a sufficient supply of sediment and space to naturally
shift around, it provides a natural buffer, dissipating wave energy and adapting its form
naturally in response to wave and tidal conditions. In addition to the flood and erosion
risk management function of a healthy beach, it can also bring additional recreational,
amenity and environmental benefits to an area.
Beach nourishment can be implemented to maintain these vital systems. As an option
for flood and coastal erosion risk management (FCERM) it is often associated with fewer
of the potential negative impacts of hard defences, such as downdrift erosion or the
process of ‘coastal squeeze’.
The SMP2 for North Norfolk has highlighted where such negative impacts could arise
and where, therefore, there is scope for change. In this way the Sandscaping approach
builds upon and develops the ideas within the SMP2.
The Sandscaping approach to coastal management can be best described as a largescale beach nourishment that aims to maximise the beneficial role of natural processes.
What distinguishes it from a more conventional linear nourishment of the shoreline
(whether through annual nourishment or larger scale linear nourishment), is that it is a
more radical, shoreline-changing approach, designed to alter the geomorphology in
such a way that the subsequent interaction with the natural processes enhances the
protection it provides and the benefits that it generates.
Some of the main benefits of a ‘Sand Engine’ are:
• Protection of existing assets and functions;
• Improved efficiency of flood and coastal erosion risk management over a larger
management area;
• Creating width within the natural coastal system that builds in resilience to
climate change; and
• Creation of a blank canvas for new economic, social and environmental
opportunities and development.
The Sandscaping / Shingle Engine beach nourishment material (of the order of 20million
m3 in the Dutch Sand Engine) is redistributed alongshore in an ecodynamic manner, into
systems such as dunes over a period of 10-20 years, therefore providing protection to a
larger area over this longer period of time.
2.2
The Dutch Sand Engine
In The Netherlands the ‘Building with Nature’ programme aims to use and build upon our
knowledge of natural systems to enable development of more sustainable approaches
to coastal, delta and fluvial management. The ecosystem is seen as the starting point
within a ‘Building with Nature’ project and natural processes are aimed to be used to
their full potential, with infrastructure and economic considerations still occurring
alongside this.
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One of the flagship ‘Building with Nature’ projects has been the Sand Engine Delfland, a
pilot implemented along part of the Zuid-Holland coastline in 2011. Initiated by the
Province of South Holland (regional government) but implemented in close collaboration
with a larger number of groups2 the scheme saw the placement of 21.5million m3 of sand
in a hook shape, designed in such a way that processes will transport the sediment
downdrift, building up the beaches and forming a coastal lagoon feature in the centre of
the newly built out area.
This coastline previously required nourishment every five years to maintain beach
levels. The Sand Engine was designed to reduce that requirement to once every 20
years. In addition to this, there are other benefits of the Sand Engine that were also
drivers for its implementation. These are:
•
•
•
Creation of significant different recreation and tourism opportunities, broadening
the attraction of the coast. Since the public have been able to access the Sand
Engine it has become the Dutch capital of kite-surfing;
More effective delivery of benefits, particularly in terms of the substantial
reduction in costs of the approach, compared with traditional beach nourishment
schemes. This is a result of multiple factors, including economies of scale effects
and effective life of the scheme.
Reduction in habitat disturbance through less frequent nourishments; and
creation of new habitats both in the borrow areas and in the nourishment areas.
The project has been partly funded by the Dutch Government (EUR €58 million) and the
Province (EUR €12 million). In terms of flood defence there is a clear priority in Holland;
without coastal defences 70% of the country would be flooded and, currently, 70% of the
total Dutch GDP is generated on land that is in areas at risk of flooding.
It is important to note that prior to the preferred ‘hook’ design, the design went through
several iterations. The guiding principle for the ultimate design was for an “ecodynamic
design”. This aims to guarantee coastal safety while also creating space for nature,
development and recreation. There was also a guiding principle of sediment volumes of
the order of 10-20million m3.
The three main areas of additional benefit delivered by the Sand Engine are used in
principle to develop the objectives and design criteria specific to the North Norfolk
Sandscaping project. These are presented in Section 4.
2
Ministry of Transport, Public Works and Water Management, local municipalities, the Water Board of Delfland,
NGOs and businesses (Building with Nature Guideline, downloaded 2013.03.18 from
http://www.ecoshape.nl/en_GB/wiki-knowledge-base.html/knowledgebase/271-Case+-+Sand+Engine+Delfland)
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3
THE STUDY AREA
3.1
Location
The study area comprises the section of the North Norfolk coast between Mundesley
and Cart Gap, as shown in Figure 3.1 below.
Mundesley
Bacton Gas
Terminal
Bacton
Walcott
Happisburgh
Cart Gap
Figure 3.1 Study Area
This Section describes the North Norfolk coastline between Mundesley and Cart Gap,
and highlights the importance of sediment and natural processes; socially, economically
and environmentally. This provides important background for the assessment of the
potential benefits and performance of a Sandscaping approach to coastal management.
3.1.1
Key features of the coastline
The coast of north east Norfolk between Cromer and Happisburgh is an almost continuous
line of glacial tills cliffs. Net sediment transport is to the south-east and the potential for
transport increases with distance south as the coastline curves from a west/east alignment,
to the west of Cromer, to a northwest/southeast alignment along the study frontage and
further to the south.
Figure 3.2 shows that between Mundesley and Walcott the coastal alignment changes.
The villages of Mundesley and Walcott, and Castaways Caravan Park at Bacton, are hard
points on the coast which form effective headlands. The coast between Mundesley and
Castaways Caravan Park forms a shallow embayment, with the beach in front of the
Bacton Gas Terminal Complex being slightly set back. In addition, the overall orientation
of the coast changes by about 10 degrees at Mundesley. These coastal features are in
part due to the historic coast protection of Mundesley and Walcott. Other factors, such as
local variation in bathymetry and the change in the underlying geology of the shoreline
may also have influenced the coastal alignment.
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Figure 3.2 Coastal alignment between Mundesley and Walcott
3.1.2
Physical Conditions
Water Levels
Table 3.1 Water Levels along the North Norfolk coast (2008 base date)
Astronomical tidal levels (mAOD) Extreme Water levels (mAOD) / return period
Site
LAT
MLWS MSL
MHWS HAT
1
10
50
100
200
1,000
10,000
Lowestoft
-1.40
-1.00
0.90
2.00
2.48
2.88
3.07
3.27
3.78
4.63
0.20
1.40
Winterton-on-Sea
-1.72
-1.22
-0.01
1.38
2.38
2.34
2.78
3.16
3.334
3.53
4.02
4.86
Bacton
-2.55
-1.58
0.11
1.88
2.71
2.86
3.28
3.64
3.79
3.96
4.39
5.08
Cromer
-2.25
-1.85
0.20
2.25
2.95
3.14
3.56
3.92
4.0.8
4.25
4.69
5.42
Waves
Nearshore extreme wave conditions at Bacton are summarised in Table 3.2, based on a
confidential report made available by the Bacton Gas Terminal operators. These waves
correspond to a water depth of 6.8m.
Table 3.2 Extreme wave conditions at Bacton
Return period
Wave height Wave period
Hs (m)
Tp (s)
1
-1.40
-1.00
10
-1.72
-1.22
50
-2.55
-1.58
100
-2.25
-1.85
Tides
Strong tidal currents occur along the North Norfolk coast. Tidal flow rates about 14km
offshore of Mundesley are shown in Table 3.3, based on Admiralty Chart 106. The
direction to which the current is flowing is given in degrees relative to True North, i.e.
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just before high water, the current is travelling approximately from the north-west to the
south-east.
Table 3.3 Tidal streams offshore of Mundesley
Time relative to HW
Direction
at Immingham
Speed (knots)
Spring Tide
Neap Tide
-6 hr
327
1.7
1.0
-5 hr
327
2.6
1.5
-4 hr
327
2.7
1.6
-3 hr
327
1.9
1.1
-2 hr
327
0.7
0.5
-1 hr
147
0.6
0.3
HW
147
1.6
0.9
+1 hr
147
2.4
1.4
+2 hr
147
2.4
1.5
+3 hr
147
1.9
1.2
+4 hr
147
1.1
0.6
+5 hr
327
0.1
0.1
+6 hr
327
1.6
0.7
Maximum flood currents (from west to east) occur about one hour after high water, and
that maximum ebb flows about one hour after low water. The tidal flow rates are sufficient
to mobilise and transport large quantities of seabed sediment. As strong tidal flows occur
around the time of the highest water levels, large waves, at the shoreline, are likely to
occur at the same time as strong tidal currents, increasing the potential for sediment
transport.
3.1.3
Geology and Geomorphology
North Norfolk District Council’s ‘Introduction to the North Norfolk Coastal Environment’
provides a simple overview of the geology, coastal processes and natural environment
of the area, and therefore this document is attached as Appendix A. An extract from
Appendix C (Baseline Process Understanding) of the Shoreline Management Plan,
describing the coastal processes between Mundesley and Cart Gap is attached in
Appendix B. The key points from these documents are summarised below.
The coastline between Mundesley and Cart Gap is characterised by soft cliffs of varying
height, which are nationally important for their geology and geomorphology. The coast is
exposed and therefore very dynamic. Rapid cliff erosion is occurring in places, and
foreshore steepening is an issue throughout this frontage. Severe storm events can rapidly
change beach levels and the degree of exposure of the natural or defended coastline.
Sediment transport rates are high, with cliff and beach erosion from the coast between
Weybourne and Lowestoft believed to contribute up to 0.8 M tonnes (approximately
0.44M m3) and up to 0.665 M tonnes (approximately 0.37M m3) of sediment per year
respectively (Balson, 1999; McCave, 1978). The general littoral drift is from the north
west to south east, with drift rates (broadly) increasing from Kelling to Happisburgh
(SNSSTS, 2001). During storm surges, large waves predominantly from the north and
north-west combine with strong nearshore tidal currents to transport large volumes of
sediment offshore and alongshore.
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The nearshore and offshore zones are characterised by shoals and sand banks, which
influence coastal exposure and wave patterns. This results in complex sediment transport
interactions between the offshore, nearshore and beach zones and has also an impact on
alongshore transport. These interactions aren’t well understood or quantified, but the
offshore bank system is understood to be a long-term sink of sand-sized sediment (ABP,
1996). Fine-grained material from the cliffs tends to be washed offshore, carried eastwards
by tidal currents (McCave, 1978; ABP, 1996; Dyer and Moffatt, 1998). It is estimated that
45% of material is lost in this way (UEA, 1971).
“The net longshore drift rates in the study area have been estimated several times in the past, with a wide
range of predictions. Much of the work has been focused on Cromer to the west and on Happisburgh to
the east. One of the earliest studies by Vincent (1979) estimated a potential net sand transport rate of
148,000m3/year at Happisburgh. This was revised by a subsequent study by Vincent, McCave, and
Clayton (1983) establishing a drift rate at Happisburgh of 260,000m3/year. Vincent, McCave, and Clayton
(1983) also estimated a rate of 100,000m3/year passing Overstrand, and Clayton (pers. comm.) estimated
a southerly drift of 180,000m3/year passing the cliffs at Trimingham, decreasing to 160,000m3/year at
Happisburgh. This reduction was thought to be a function of sand being lost offshore. All these estimates
have been made assuming that the coastline was still in a natural state, i.e. with no groynes or other
coastal defences that affect the transport of beach sediment.”
Overstrand to Walcott Strategy Study, Littoral Sediment Processes
HR Wallingford Report EX 4692, 2003
As part of the Overstrand to Walcott Strategy Study, HR Wallingford undertook numerical
modelling of sediment transport between Cromer and Bacton. This modelling determined
upper and lower bound potential drift, shown in Figure 3.3 below to be of the order of
350,000m3/year at Bacton. Potential sources of error in these theoretical calculations
include availability of sediment to satisfy the calculated drift rate, numerical modelling of
the waves, and influence of tidal currents.
Figure 3.3 Average Mean Annual Potential Drift (HR Wallingford, 2003)
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3.1.4
Analysis of SCAPE model results
The Cromer to Winterton Ness Coastal Strategy (Mott MacDonald, 2013) used the
SCAPE model (developed by the Tyndall Centre) to develop a holistic understanding of
the inter-linked coastal processes along the frontage, considering the current and future
coastal defence conditions. The results from the SCAPE model provide an indication of
how coastal processes may change and impact cliff recession rates along the coast under
different management scenarios. Royal HaskoningDHV was appointed by Mott
MacDonald to undertake SCAPE modelling as part of the development of the Strategy.
The SCAPE model was run between Cley-next-the-Sea and Winterton Ness to calculate
sediment flux along the frontage and predict the geomorphological response of the coast
between Cromer and Happisburgh to ‘Do Nothing’ (Management Scenario 1) and ‘SMP
Policy 6’ (Management Scenario 2). Management Scenario 1 represents a general
policy of not intervening with the future failure of coastal structures, whilst Management
Scenario 2 represents implementation of the preferred policies of the recent Shoreline
Management Plan review.
The SCAPE model represents the coast by 500m-long segments, within which the shore
profile, beach volume and wave conditions are assumed to be constant over that 500m
segment at any instant of time. The model was run to 2120 for the two management
scenarios and under predicted climate change projections (represented in the model
through effects on sea-level rise and wave activity).
The management scenarios were represented in the model by ‘switching off’ the seawalls,
revetments and groynes, to reflect the expected time of failure or removal of the defence
at each location for each management scenario. The reported outputs from the model
included projections of longshore sediment transport rates at Cart Gap, where the cliffs
meet low-lying land and the coastline is particularly vulnerable to loss of sediment.
For this feasibility study, further data produced as output from the SCAPE model (but not
previously published) have been analysed within the context of possible sandscaping in
the area between Mundesley and Bacton. These data include predicted longshore
sediment transport rates at locations between Trimingham and Sea Palling, for each year
between 2013 and 2120 for Management Scenarios 1 and 2. These data have been used
to determine how the rates are predicted to differ for each scenario, and what the
implications would be for a sand engine at Bacton. Data has been analysed at the
following locations:
•
•
•
•
•
•
•
•
Trimingham (Sections 56 to 58);
Mundesley (Sections 48 to 53);
Bacton (Sections 43 to 45);
Walcott (Sections 35 to 37);
Happisburgh (Sections 30 to 32);
Cart Gap (Section 29);
Eccles (Sections 25 to 27); and
Sea Palling (Sections 19 and 20).
The report of this analysis is included in Appendix C and summarised below.
Comparisons of sediment transport rates show that if a ‘Hold the Line’ strategy is adopted
at Mundesley in accordance with SMP policy, then smaller volumes of sediment would be
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transported south than if a Do Nothing policy (Management Scenario 1) is adopted and the
structures protecting the coast fail generally within the next 10 years. An additional 65,000130,000m3/year of sediment would be transported along the Mundesley frontage if failure is
allowed to take place. It may be concluded that the system has a sediment deficit of
around 130,000m3/year to the south of Mundesley compared to a naturally functioning
system.
It is recognised that sections of the northeast Norfolk coast appear to benefit from
occasional gluts of sediment apparently progressing down the shoreline. Despite this, and
taking account of the significant yearly variation in sediment at specific locations, beach
levels at Mundesley and over the coast further to the south, at Bacton and Walcot, have all
been shown to be decreasing in volume overtime. This is most noticeable in front of the
Walcott frontage. In line with the findings of the SMP, it seems sensible to attribute this
progressive change in part due to the fixed position of the shoreline defences, constraining
the width of the naturally developing shoreline profile, and as a result of the sediment deficit
identified above.
The SCAPE results also show present-day sediment transport rates at Cart Gap to be
about 160,000m3/year (based on the existing pattern of defences to the north). This
sediment flux is not sufficient to maintain beach levels to the south of Cart Gap, with the
Environment Agency continuing a programme of beach nourishment to replenish losses
of beach volume of the order of 150,000m3/year on average. As shown by Figure 3.2,
previous studies have estimated potential sediment transport rates between Bacton and
Happisburgh to be 300,000 to 400,000m3/year. This is consistent with the unconstrained
drift rates determined within the SCAPE model. It is reasonable to assume that this total
volume equates to the present-day sediment transport rate (approx. 160,000m3) plus the
deficit due to coastal protection to the north (approx. 130,000m3).
While it is recognised that there is loss of sediment to the nearshore system, the above
results do highlight an overall consistency in the linkage of sediment drift along the whole
frontage.
The SCAPE analysis has also be used to give an indication of how quickly sediment
moves along the frontage. This has been based on the time taken for sediment
difference patterns (i.e the difference in sediment flux between the two scenarios
modelled) to develop at different sections of the coast. The analysis has considered
these differences over the section of coast between Mundesley and the Walcott frontage
and by implication potentially in relation to the coast further to the south.
The analysis, in terms of “sediment speed”, are complicated by:
• The differences in failure times at specifc locations assumed by the SCAPE
model.
• The additional volumes supplied to the system within the model by failure of
defences at specific locations along the frontage, and
• The smoothing process caused by the vagaries of the wave climate used within
the model.
However, as seen in Figure 3.4 (sediment drift differences at Mundesley (a) and Walcott
(b)), there are strong patterns in the sediment drift difference profiles that can be seen to
develop over the frontage as a whole.
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Peak difference on defence failure at Mundesley
Bulk difference due to on-going additional supply
Figure 3.4a. Differences in predicted longshore sediment transport rates between
Management Scenarios 1 and 2 for the period 2013 to 2120 at Mundesley. Positive
values indicate that rates predicted for Management Scenario 1 are higher than
Management Scenario 2
300,000
Potential Walcott peak
35
36
250,000
Sediment Transport (m3/year)
37
200,000
Potential increased drift from north
Potential bulk input from north
150,000
100,000
50,000
0
2010
2030
2050
2070
2090
2110
-50,000
-100,000
Figure 3.4b Difference in predicted longshore sediment transport rates between
Management Scenarios 1 & 2 at Walcott. Positive values indicate that rates
predicted for Management Scenario 1 are higher than Management Scenario 2
If it is assumed that the sediment from the north (due to failure of structures at Mundesley
and Bacton in the mid-2020s) starts to affect the Walcott frontage in 2040 (as the difference
in transport rates starts to climb as the second “bulk” peak, Figure 3.4b), then the influence
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from the north has travelled about 4km in 15 years. This equates to a worst-case transport
‘speed’ of about 250m/year.
More realistically, based on comparisons between Mundesley and Bacton frontages, if it
is assumed that sediment arrives at Walcott as the downward slope of the main peak
becomes shallower (around 2030, Figure 4.3b), then it has travelled about 4km in 5 years
or 800m/year. If the overall shape of the difference profiles are compared then the
increased sediment flux from the Mundesley area appears to be influencing Walcott within
about 2 years, with a speed of travel around 2km/year (best-case transport ‘speed’). If
the medium rate of 800m/year is assumed to continue further to the south, then sediment
from the sand engine would take approximately 8 years to reach Cart Gap.
3.1.5
Beach Behaviour
The Environment Agency regularly surveys the beach profiles along the study frontage.
Data from these surveys was analysed, for the period from 1991 to 2014. The figures
included in Appendix D include examples of the beach profiles measured in this period,
reflecting the maximum and minimum levels of the upper beach, and showing the profile
recorded by the most recent survey.
The volume of the upper beach from the hard defence line (or the toe of the cliff face) to
the level of Lowest Astronomical Tide (-2.5mAOD) was determined for each profile. The
variation in beach volume over time is shown in Figure 3.5.
Figure 3.5. shows that beach volumes have reduced by up to 5m3/m/year between
Mundesley and Walcott over the period from 1991 to 2014. However, over the last 10
years, beach volumes have been decreasing by about 10m3/m/year. Beach volumes
can fluctuate by +/-100m3/m between monitoring periods, although the change is rarely
more than 50m3/m.
For comparison with previous beach volume analyses, the Overstrand to Walcott Strategy
Study (2003) determined an annual average rate of beach volume loss of 48,000m3 over
the entire frontage from Cromer to Walcott, which equates to about 2.5m3/m over the
18km frontage. It should also be noted that erosion of 150,000m3/year on average from
the Happisburgh to Winterton frontage equates to a reduction in beach volume of 11m3/m
over this 13.5km frontage.
The beach volume analysis also gives an indication of the likely ‘speed’ at which sediment
moves along the frontage. A comparison of the peaks in beach volume between adjacent
beach profiles shows a time lag of 6 to 18 months between the peaks. This shows that
sediment is moving along the coast at a ‘speed’ of 500m to 2km per year.
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N069
N070
N071
N072
N073
N074
Variation in Beach Volume (HAT to LAT), Profiles N069 - N074
Beach Volume above LAT (m3/m)
600
500
400
300
200
100
0
1990
1992
1994
1996
1998
2000
2002
2004
Date
2006
2008
2010
2012
2014
Figure 3.5 Variation in Beach Volume
3.1.6
Present Management of the Coast
The Cromer to Winterton Ness coastline is covered by the ‘Kelling to Lowestoft Ness
Shoreline Management Plan’ (2005). The Shoreline Management Plan (SMP) has
divided the coastline into a number of individual Policy Units. From Cromer to Winterton
Ness there are 9 Policy Units (Figure 3.6) for which management policies are defined for
the short term (0-20 years), medium (21-50 years) and long term (51-100 years).
The recommended SMP management policies (Table 3.4) have been developed based
on the assumption that the impact of a Hold the Line policy in one area is likely to
increase erosion further to the south due to limits in sediment supply. This has resulted
in Hold the Line management policies only in the short (0-20 years) or medium (21-50
years) terms in many Policy Units.
Table 3.4 Management scenarios recommended by the SMP
SMP Policy Unit
Short term (0-20 yrs)
Medium term (21-50 yrs)
Long term (51-100 yrs)
6.05 Cromer to Overstrand
Managed Realignment
No Active Intervention
No Active Intervention
6.06 Overstrand
Hold the Line
Managed Realignment
Managed Realignment
6.07 Overstrand to Mundesley
Managed Realignment
No Active Intervention
No Active Intervention
6.08 Mundesley
Hold the Line
Hold the Line
Managed Realignment
6.09 Mundesley to Bacton Gas
Managed Realignment
No Active Intervention
No Active Intervention
6.10 Bacton Gas Terminal
Hold the Line
Hold the Line
Hold the Line
6.11 Bacton Walcott & Ostend
Hold the Line
Managed Realignment
Managed Realignment
6.12 Ostend to Eccles
Managed Realignment
Managed Realignment
Managed Realignment
6.13 Eccles to Winterton
Hold the Line
Hold the Line
Hold the Line
Terminal
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Figure 3.6 SMP Policy Units
North Norfolk District Council have been developing a strategic approach to management
of their coast and recently undertook a study into the movement of sediment along the
whole area, examining how defence in certain areas may influence drift patterns between
Cromer and Happisburgh and further to the south between Cart Gap and Winterton. The
southern area (Eccles to Winterton) is heavily dependent on sediment feed from the north
and provides defence to a large low lying hinterland.
The Bacton Gas Terminal is located within the study area and is one of the three main
gas terminals in the UK, receiving gas from the North Sea extraction fields. Despite the
presence of various coast protection measures, the cliffs to the terminal frontage have
continued to erode in recent years such that the Gas Terminal and its associated
infrastructure is now under direct threat from the sea.
The village of Walcott within the study area is a small but important village, which has
relied upon its beach as an integral element of its defence. The beach is also an
important feature of the village sustaining its tourism and recreational value. The
Environment Agency has maintained the sea wall that protects the village and low lying
land behind. In the past three years, beach levels at Walcott have been at their lowest
for over 25 years, up to 3m below the crest of the sea wall.
The 14km long Eccles to Winterton frontage protects a hinterland which includes
internationally-designated sites of high environmental value, as well as productive
agricultural land, residential and commercial properties. The environmental sites include
large areas of fresh water fens and open water habitats, which are particularly sensitive
to saline inundation. Natural England has stated that management of the flood defences
to prevent saline inundation is necessary over the next 20-50 years whilst investigation
of longer term managed realignment options takes place.
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The area has had recognition nationally following the loss of properties at Happisburgh,
due to failing defences and subsequent erosion, and over the discussion and protest at
plans put forward in the SMP2 to allow coastal retreat at Overstrand and Mundesley. The
defences in this area suffered further damage during the 2013/14 winter storms. This
presents an immediate problem in terms of defence, while exacerbating longer term
management concerns for this frontage as identified in the SMP2.
Falling beach levels, retreat of the coastline and the management of the supply and
throughput of sediment along the coast are fundamental issues for management of the
area. This impacts directly on coastal defence and risk management, amenity and
economic regeneration and on the ecological value of the area. There are significant and
immediate issues that need to be resolved, as well as issues for longer term management.
3.2
Natural Environment Constraints & Opportunities
The assessment of natural environment constraints and opportunities associated with
potential sandscaping between Bacton and Walcott is attached as Appendix E and
summarised in Table 3.4 below. Protected sites in the study area are shown in Figure 3.6.
Legend
WFD River Waterbodies
Cycle 2 (Draft)
WFD Lake Waterbodies
Cycle 2 (Draft)
WFD Coastal Waterbodies
Cycle 2 (Draft)
rMCZ
SPA
SAC
SSSI
Figure E2 Protected Sites in the Study Area
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Table 3.6 Summary of Environmental Constraints and Opportunities
Item
Rationale
Constraint /
Opportunity
The SMP/SEA identified that a reduction in sea defences along this area of coastline could result in positive impacts in terms of establishing of
beaches natural functioning of the coast and sediment supply to European protected sites. In particular as identified in the following sections
Mundesley Cliffs in the immediate vicinity of Bacton are designated as SSSI for natural exposure and within policy area 6.10 (SEA 2013). The
policy for this unit is currently to hold the line which could affect the natural processes for this area as well as Winterton and Horsey Dunes SAC.
Although the policy aim is conditional on further monitoring and there are measures within the policy for beach recharge which should be
considered in relation to the sandscaping option.
Opportunity
Management Policies
Sea defences
Environmental Designations
Natural England would like the following information to be provided as part of any future studies in order to come to a view on impact to the SSSIs including: likely changes to erosion rates; likely
beach levels; likely cliff profiles; quantity of sediment, the likely future profile of the coastline and how current coastal processes will operate. E.g. is the anticipation that there will be a massive
beach such that waves will rarely reach the cliffs and thereby reduce or even stop erosion from waves for a period of time? Or is the plan to place the sand slightly offshore such that wave breaking
might occur which may limit the erosive power of waves but still allow waves to reach the beach and cliffs and allow some erosion to still occur?
Mundesley and
Happisburgh Cliffs SSSI
These cliffs are both designated SSSI of geological interest only. Both are designated for cliff exposure of the Cromer Forest bed and contain fossil
layers of interest. Till deposits are important features as well. The target for both of these sites is to maintain the natural coastal processes for
exposure of the cliff. The main exposure area to maintain is in the upper cliff at Mundesley. Natural England considers that a build-up of sediment
at the base of the cliff to slow the rate of exposure is acceptable but not to the extent that exposure is prevented. The rate of sediment deposition
needs to be within acceptable limits.
Constraint and
Opportunity
Winterton and Horsey
Dunes SSSI and SAC
This dune system is designated SSSI and SAC. The interest feature here is the breeding tern colony. The designation is to protect breeding and
feeding habitats within the dune system. There could be a benefit of the development of a foredune area as a result of sediment deposition since
high tides and scour have removed some of the habitat in the recent past. However if there is a build-up of sediment in the future as a result of
sandscaping Natural England would not agree to this being removed at a future date for recharge or sandscaping purposes.
Opportunity
Overstrand Cliffs
SSSI/SAC, Sidestrand &
Trimmingham Cliffs SSSI
Geological notified features at the SSSIs comprise the entire cliff profile therefore erosion and sedimentation rates should consider the whole cliff
feature.
Constraint
Happisburgh Hammond
Winterton Offshore SAC
Any removal or deposition of sediment in this area would need to avoid any impact to the features associated with this SAC namely the Sandbanks
slightly covered with seawater at all times and the Sabellaria spinulosa reefs.
Constraint
AONB Happisburgh to
Winterton
Natural England considers that archaeology is an important consideration at Happisburgh. The foreshore here (the Cromer Forest Bed) has
evidence of early humans and this is thought to be the site with the oldest evidence of human occupation in Britain. There has been considerable
Constraint
SPA feature (little tern)
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Item
Rationale
Constraint /
Opportunity
interest in this site and the advice is that English Heritage should be consulted regarding impacts to the archaeology.
Marine Conservation Zones
Cromer Chalk Beds rMCZ
This area may be protected as a designated MCZ in January 2015. Within the chalk reefs are a considerable number of biotopes and species
which could be adversely affected by sediment deposition depending on the nature, depth and duration of the deposited material.
Constraint
There is a potential for the deposition of sediment within the area designated as a coastal waterbody depending on where the sediment for the
sandscaping is placed. This could affect the mitigation measures already in place especially those relating to sediment management and site
selection of dredge material for disposal.
Constraint
Water Framework Directive
WFD Coastal Water Body
– Norfolk East
Fishing and Fish & Shellfish Ecology
Beach landing
Most of the inshore boats are beach landed. If there was a change in beach morphology as a result of the rate and level of sediment deposition this
would adversely affect the ability to land boats. The offshore fleet of CATS are also landed on beaches.
Constraint
Gear loss
High levels of sediment deposition could smother gear such as pots.
Constraint
Disruption to fishery
industry
Many boats are also processing the catch on-board, beach boats and the larger CATS which also land on the beaches. Loss of beaches will cause
substantial disruption to the industry.
Constraint
Effect on fishing areas
The rates and depths of deposition need to be considered especially if there is a potential for the inshore areas such as firmer ground to be affected
by deposition or removal of sediment.
Constraint
Water quality
Shellfish require good water quality and a food source. There needs to be a consideration of the effect on the food chain of changes to sediment
patterns and distribution. Heavy deposition may affect the distribution of shellfish and flatfish through the alteration of habitats. High sediment
concentrations could affect filter feeding mechanisms and cause smothering in shellfish.
Constraint
Safety
Potential changes in the seabed morphology and possibly the existing sand banks may affect the safe waters.
Constraint
Stakeholder engagement
Lack of engagement with the fisheries industry early in the process will be detrimental to support for the process. There is a lot of local knowledge
about the seabed, sand areas and sand movement
Constraint
Fish and shellfish ecology
A consideration of the spatial distribution of fish and shellfish species is needed in relation to potential smothering and loss of habitat. Crab and
lobster migration routes and female burrowing areas, benthic habitats for bottom dwelling species may potentially be affected by high suspended
sediment loading and changes in habitat character as a result of removal or deposition of material.
Constraint
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3.3
Socio-Economic Considerations
The population of Mundesley is approximately 2,500. The villages of Bacton, Walcott and
Happisburgh all have populations of less than 1,000.
The coast in this area, particularly in relation to Cromer, is regionally important for tourism,
and for its recognised tourism potential. Over 37,000 people are employed in the tourist
industry in Norfolk and Waveney. However, the area from Cromer to Winterton is seen as
being remote and its potential is under developed. Over the last three decades, works
undertaken at Sea Palling to restore and control the beach have substantially increased
visitor numbers.
Other key land uses include residential, agriculture, industry and recreation. Norfolk has
a long history as an agricultural area and has an important fishing industry based around
the coast. A significant area of Grade 1 agricultural land is located between Bacton and
Waxham (south of Cart Gap). Other economic considerations include port and harbour
operations, including lifeboat stations, roads, water and sewerage infrastructure, gas and
power lines.
3.4
Potential for Sandscaping
Based on the issues described above, the use of large scale sediment nourishment to
replenish and sustain sediment supplies could have significant benefits for this part of
the North Norfolk coast, and potentially over a wider area. Any Sandscaping project
would need to provide immediate protection to the Bacton Gas Terminal site, but there
are significant additional and longer term benefits that could ensue. Opportunities
include the potential to increase the amenity value of the area, the reduction of
environmental impacts associated with current coastal management policy, and
enhancement of natural environment features such as the Horsey dunes. Therefore the
area between Mundesley and Walcott is seen as having a strong potential for
developing a Sandscaping approach to management.
Earlier Sandscaping studies have shown that there is a wide range of possible shapes,
sizes and functionalities. In terms of form and function, we consider that it would need to
work in a similar manner as the Delfland Zandmotor, substantially building forward the
beach in its immediate area of placement and regulating and supplying sediment drift
across the frontage. This study does not develop a proposed layout for a sand motor.
The main question that needs to be resolved is the sand motor’s ability to feed sediment
in to the system, in terms of the broader benefits the scheme would need to deliver and
the expected time that the protection and other benefits would last, in relation to the
required investment.
The key issues would, therefore, be to:
• ensure that Sandscaping can meets the immediate need and provides longer
term protection to the Bacton terminal,
• identifying the additional benefits that may be derived, over and above those that
might be delivered taking a local approach to defence of the Bacton site.
• assessing whole life costs and benefits of a Sandscaping solution to enable
comparison with those of a more traditional, technical local solution.
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The overall aim of this study is to demonstrate the technical practicality of the approach
whilst also examining how additional benefits may be created through defining design
criteria for a sand engine. The study will define the size (in terms of quantity of material)
of a sand motor that would be needed to provide both local protection and wider
benefits. The study will support short-term decision making about protection measures
at Bacton, and therefore has to provide a comparable level of confidence in its costs and
benefits as any more local solutions under development for the protection of Bacton.
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4
OBJECTIVES FOR SANDSCAPING
The following objectives for the implementation of a sandscaping approach to beach
nourishment between Mundesley and Walcott were defined based on discussions with
the wider project team at the project inception meeting (27th August 2014).
4.1
4.2
Functional Performance Objectives
•
Proposals for sandscaping to be developed based on a thorough interrogation of
evidence and a strong understanding of the coastal processes so that impacts on all
constraints and the risk of unintended consequences are minimised.
•
To provide coast protection to the Bacton Gas Terminal, which is nationally important
critical infrastructure with a direct asset value of over £200m.
•
To reduce the risk of erosion and defence failure to the Bacton, Walcott and Ostend
frontage in the short term (0-20 years) as a minimum, in accordance with SMP policy.
•
Sandscaping nourishment to be of sufficient size to influence the coastal processes,
so that beach levels are maintained at key locations whilst also maintaining and
potentially enhancing sediment drift along the coast.
•
To optimise the effective life of any nourishment programme, considering the
associated timescales for downdrift impacts (e.g. when will upstream nourishment
reach Cart Gap?).
•
To optimise the balance between the presence of a beach that provides protection
against erosion, and the reduction of sediment supply from the cliffs.
•
To minimise impacts on, and where possible enhance, the natural environment,
including foreshore and nearshore habitats, geological features and fisheries.
Opportunity Benefits
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected
elsewhere, e.g. Cart Gap (nourishment programme) and Mundesley (proposed HtL
scheme).
•
To enable an alternative approach to adaptation to coastal change that manages
and balances the conflicting issues for coastal management on this part of the North
Norfolk coast.
•
To maximise the positive natural environment benefits of the scheme, e.g. creation of
intertidal habitat, reduced habitat disturbance through reduced frequency of
nourishment at Sea Palling.
•
To maximise the potential benefits to local businesses, and for inward investment for
economic growth of the area.
•
To provide positive benefits to the local communities, through improved erosion risk
management (with associated safety and welfare impacts), and creating the potential
for improving quality of life in other ways.
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5
DESIGN CRITERIA AND ASSUMPTIONS
Based on the objectives set out in Section 4, and our developed understanding of the
local physical and natural environment, design criteria for the performance of a
Sandscaping project were identified.
5.1
Effective Life of Scheme
•
To optimise the effective life of any nourishment programme, considering the associated
timescales for downdrift impacts (i.e. when will upstream nourishment reach Cart Gap?).
For the purposes of this feasibility study, a Sandscaping scheme will be assumed to
have a design life of 50 years. This timescale is sufficient to demonstrate commitment
to investment in coast protection infrastructure to enable inward investment to be
encouraged, whilst avoiding very long-term commitments to ongoing capital and
revenue costs.
For consistency with the 2013 Coastal Study, the assessment of costs and benefits will
be undertaken over a 100 year period. The economic appraisal will therefore assume
that the management policy reverts to the SMP policy after year 50.
To maximise the efficiency of large-scale beach nourishment in terms of construction
economies of scale and minimised environmental disturbance, the frequency of
nourishment campaigns is significantly reduced from the more typical one to five year
cycle. The Sand Engine Delftland was designed based on nourishment being
undertaken every 20 years. This study currently assumes a 25-year nourishment cycle.
Based on the SCAPE analysis (Section 3.1.4) and beach volume analysis (Section
3.1.5), it is reasonable to assume that sediment moves along this part of the coast at a
rate of about 800m per year. Therefore, sediment placed in the vicinity of the Bacton
Gas Terminal Complex would take about 9 years to reach Cart Gap 7km to the south.
Consequently, the positive benefits of upstream nourishment would not be realised for 9
years, and the current nourishment campaign would need to continue over this period.
5.2
Risk Management
5.2.1
Risk Management - Bacton Gas Terminal Complex
•
To provide protection to the assets associated with the Bacton Gas Terminal Complex
(nationally important critical infrastructure with a direct asset value of over £200m) for at
least 50 years.
•
To enable an alternative approach to adaptation to coastal change that manages and
balances the conflicting issues for coastal management on this part of the North Norfolk
coast.
For the Bacton Gas Terminal Complex, the following options will be considered:
• Sandscaping nourishment along the Gas Terminal frontage sufficient to achieve
SMP policy (Hold the Line to 50 years), followed by construction of hard
defences after Year 50.
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•
Sandscaping nourishment further south (Bacton to Walcott frontage), requiring
additional investment in hard defences at the toe of the cliffs.
The typical design standard for UK coast protection schemes is a 1:200 year standard of
protection. However, it is understood that the operators of the Terminal Complex require
an enhanced standard of protection to reduce the risk of damage to their assets to ‘As
Low As Reasonably Practicable’ (currently assumed to be a 1:10,000 year standard of
protection). Therefore the costs included in the economic appraisal for the SMP policy
option relate to this enhanced design standard.
The proposed beach nourishment profiles for a Sandscaping scheme should be based
on the relevant extreme water levels, accounting for climate change over the 50 year
design life. Astronomical tide levels and extreme water levels for this part of the East
Anglia coast are given in Table 3.1.
To determine sea level rise allowances to account for climate change, Environment
Agency advice is to use the UK Climate Projections 20095 (UKCP09) estimates, which are
to a 1990 baseline and based on the Intergovernmental Panel on Climate Change (IPCC)
4th Assessment Report. These estimates are available for low, medium and high
emissions scenarios and presented by UKCP09 as central estimates of change (50%
confidence level, 50%ile) in each scenario with an upper 95% confidence level (95%ile)
and a lower 5% confidence level (5%ile). UKCP09 also provides low probability, high
consequence allowances for sea-level rise up to 2100 (H++ scenario range), which is
useful as a sensitivity analysis of worst-case change, and for contingency planning in
case climate change were to happen much more rapidly than expected. The Environment
Agency recommends using the 95%ile estimates of the medium emissions scenario for
risk management, to account for potentially larger rises in sea level due to e.g. melting of
the polar ice caps.
Figure 5.1 Potential sea level rise at Bacton to 2065
Figure 5.1 shows that a sea level rise allowance of 0.4m is appropriate for a Sandscaping
scheme in the vicinity of Bacton with a 50-year design life. The resulting design water
level is given in Table 5.1.
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Table 5.1 Design Water Levels for Sandscaping at Bacton
Criteria
1:200 year standard
of protection
Extreme water level (mAOD)
3.96
Sea level rise allowance (m)
0.40
2065 Design water level (mAOD)
4.36
For the purposes of this study we have assumed a design crest level of +5.0mAOD, with
a minimum berm width of 50m to minimise the risk of damage to cliffs or defences from
wave impact. The design wave conditions and associated risk of wave impact damage
or overtopping would need to be assessed more accurately during scheme design.
This project has not considered design criteria to reduce the risk of cliff erosion due to
slumping or weathering.
5.2.2
Risk Management - Bacton to Walcott frontage
•
As a minimum, to maintain the standard of protection currently provided by the defences
to the Bacton, Walcott and Ostend frontage, reducing the risk of failure in the short term
(0-20 years), in accordance with SMP policy.
•
To consider opportunities to improve the standard of protection provided to Bacton,
Walcott and Ostend frontage, to reduce the risk of defence failure in the medium term
(up to 50 years).
•
To enable an alternative approach to adaptation to coastal change that manages and
balances the conflicting issues for coastal management on this part of the North Norfolk
coast.
For Bacton, Walcott and Ostend (Policy Unit 6.11), the recommended SMP management
scenario is Hold the Line in the short term, followed by managed realignment. However,
for Sandscaping to be justified in broader economic terms (e.g. opportunity creation such
as encouraging inward investment), coastal protection will need to be maintained for at
least 50 years.
Therefore the assessment of the benefits of Sandscaping will consider the following
options:
•
Sandscaping nourishment that maintains the existing standard of protection to
the Bacton, Walcott and Ostend Policy Unit, but reduces the rate of deterioration
of the defences, assumed to extend the residual life by 20 years.
•
Sandscaping nourishment that improves the standard of the defences
throughout the Bacton, Walcott and Ostend frontage to ‘Hold the Line’ for 50
years.
To maintain the existing standard of protection to Bacton, Walcott and Ostend, the beach
level would need to be maintained at its current level as a minimum. Therefore the
Sandscaping nourishment would need to compensate for beach erosion. As described in
Section 3.1.2, analysis of beach erosion rates over the last 10 years indicates that about
10m3/m is lost from the beach profile each year. Therefore up to 30,000m3 of beach
material would need to be provided each year to the 3km frontage from the north of
Bacton village to the south end of Walcott.
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To increase beach levels along the Bacton to Walcott frontage to provide a 50-year
standard of protection against defence failure, it would be necessary to raise the beach
crest level to at least +4m AOD, with a minimum crest width of 15m and a maximum slope
of 1:15. For this beach profile, a total nourishment volume 900,000m3 would be required
for the 3km frontage, in addition to the annual feed of sediment of 30,000m3/year to
maintain the beach volume.
As the existing defences to the Bacton to Walcott frontage have a residual life of about
10 years, an alternative to direct placement of nourishment material would be to rebuild
beach levels via natural transport processes over this timescale. This would require a
sediment feed of 150,000m3/year for the first 10 years of the Sandscaping scheme, with
a continued feed of 30,000m3 each year after that to maintain beach levels. For this
approach, additional investment in beach management in order to reprofile the sediment
over the 3km frontage is likely to be necessary for the first 10 years.
5.2.3
Risk Management – Mundesley
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected
elsewhere, e.g. Cart Gap (nourishment programme) and Mundesley (proposed HtL
scheme).
SMP Policy for Mundesley is to Hold the Line to year 50. To achieve this policy, it is
currently assumed that investment in defence improvements would be required.
This study has not considered options to nourish the beach at Mundesley. However,
sandscaping nourishment to the south of Mundesley could improve the condition of the
beaches at Mundesley as material is retained updrift of the nourishment area. An
increase in beach volumes would be expected to extend the residual life of the defences
at Mundesley and enable investment in improvements to the defences to be delayed. It
is therefore assumed that:
5.2.4
•
Sandscaping nourishment to the Gas Terminal frontage would extend the life of
the Mundesley defences by 20 years.
•
Sandscaping nourishment to the Bacton, Walcott and Ostend frontage would
require investment in defence improvements at Mundesley equivalent to that
required with the SMP management policy.
Risk Management - Ostend to Eccles
•
To enable an alternative approach to adaptation to coastal change that manages and
balances the conflicting issues for coastal management on this part of the North Norfolk
coast.
For Ostend to Eccles, SMP policy is for managed realignment in all epochs. It is not
proposed to extend the Sandscaping nourishment over this frontage, however
nourishment would be expected to provide some additional protection to this section of
the coast due to alongshore transport of sediment. This might be expected to reduce
erosion rates compared with the Do Nothing and SMP Policy Scenarios.
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5.2.5
Risk Management - Eccles to Winterton
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected
elsewhere, e.g. Cart Gap (nourishment programme) and Mundesley (proposed HtL
scheme).
•
To enable an alternative approach to adaptation to coastal change that manages and
balances the conflicting issues for coastal management on this part of the North Norfolk
coast.
For Eccles to Winterton (Policy Unit 6.13), SMP policy is to Hold the Line to Year 100. It
is assumed that a Sandscaping nourishment scheme would achieve a sediment flux at
Cart Gap equivalent (as a minimum) to existing EA nourishment, i.e. no requirement for
additional nourishment and associated costs. The timeframe for sediment for material
from the Sandscaping nourishment to reach Cart Gap needs to be taken into account
(as discussed in Section 5.1).
5.3
Coastal Processes
5.3.1
Volume of Sediment
•
Sandscaping nourishment to be of sufficient size to influence the coastal processes, so
that beach levels are maintained at key locations on adjacent parts of the coast whilst
maintaining and potentially enhancing sediment drift along the coast.
As described in Section 3.1.4, there is currently a deficit of about 130,000m3/year in the
sediment budget for the area due to coast protection at Mundesley and further north. This
is roughly equivalent to the volume of beach nourishment that is required annually between
Happisburgh and Winterton (150,000m3/year on average). It is therefore reasonable to
assume that if an additional 150,000m3/year is supplied into the sediment system in the
vicinity of Bacton, it will no longer be necessary to undertake additional nourishment to the
south of Cart Gap.
Also described in Section 3.1.4, current sediment transport rates from Mundesley towards
Bacton are about 130,000m3/year. Sandscaping nourishment in the vicinity of Bacton
would prevent this material from moving through the system past Bacton and Walcott and
towards Cart Gap. Although this material is not lost from the coastal system, the location,
plan form and profile of the Sandscaping nourishment will need to ensure that at least
130,000m3/year is able to be transported further south.
An ongoing study for the Bacton Gas Terminal operators has determined that erosion of
the cliffs fronting the complex (1.8km length) contributes approximately 5,000m3/year on
average. If large-scale beach nourishment was placed in front of the cliffs, although
erosion of the cliffs would not be completely prevented, this sediment would not be able to
move into the sediment transport system. Assuming nourishment extends over this entire
frontage, this volume needs to be accounted for in the design of a Sandscaping scheme.
As discussed in Section 5.2.2, Sandscaping nourishment would also need to provide
sufficient sediment to account for volumes currently provided by beach erosion, i.e.
30,000m3/year, assuming the nourishment extends for 3km.
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Based on our experience of beach nourishment, an additional 25% of the total volume
should be allowed for the first nourishment campaign, as a sacrificial volume for
construction losses, to enable the design profile to be achieved, and as a buffer to ensure
that a minimum beach profile is maintained towards the end of the nourishment cycle. This
sacrificial volume is unlikely to be required for subsequent nourishment campaigns.
Table 5.2 summarises the total volume of sediment that would be required to maintain
current sediment transport rates, accounting for the requirements for nourishment to the
south of Cart Gap.
Table 5.2 Nourishment volume required for Sandscaping
Current sediment source
Volume
Sediment budget deficit due to coast protection
5,000 m3/year
Cliff erosion
30,000 m3/year
Beach erosion
Sub-total
Sub-total (25 year nourishment cycle)
25% sacrificial/buffer volume
TOTAL (25 year nourishment cycle)
5.3.2
130,000 m3/year
165,000 m3/year
4,125,000 m3
1,031,250 m3
5,156,250 m3
Nourishment Location, Plan Shape and Profile
•
Sandscaping nourishment to be of sufficient size to influence the coastal processes, so that
beach levels are maintained at key locations on adjacent parts of the coast whilst
maintaining and potentially enhancing sediment drift along the coast.
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected
elsewhere, e.g. Cart Gap (nourishment programme) and Mundesley (proposed HtL
scheme).
The nourishment volumes required for a Sandscaping scheme, as set out in Section
5.3.1, provide sufficient volumes of material to account for the requirements for beach
nourishment to the south of Cart Gap.
If nourishment is placed adjacent to the Bacton Gas Terminal, this would have greater
potential to improve the beaches at Mundesley, with sediment being retained updrift.
Under this scenario, the residual life of the defences at Mundesley would be extended,
and the need to invest in improved defences would be delayed.
If nourishment is placed further to the south, this would increase the residual life of the
defences to the Bacton, Walcott and Ostend frontage, reducing the risk of erosion and
consequently extending the timescale over which a ‘Hold the Line’ coastal management
policy can be achieved along this frontage.
Therefore two alternative scenarios for the location of a Sandscaping scheme are
considered by this feasibility study, as examples of what could be implemented:
1. Adjacent to the Bacton Gas Terminal complex as the principal means of erosion
risk management to this frontage; and
2. At the northern end of the Bacton, Walcott and Ostend frontage, with a more
limited quantity of nourishment material extending northwards as protection to the
Gas Terminal in combination with smaller-scale hard defences.
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Based on the assessment of water levels and wave conditions, and current beach profiles
along the frontage, a crest level of +5.0mAOD is assumed, with a crest width of 150m to
200m, and a beach slope of about 1:30. With a total nourishment volume of 5 million m3,
this provides sufficient material to create a Sandscaping scheme over a frontage length of
up to 3km.
5.4
Environmental Constraints
•
To minimise impacts on, and to enhance were possible, the natural environment including
foreshore and nearshore habitats, geological features and fisheries.
•
To optimise the balance between the presence of a beach that provides protection against
erosion, and the reduction of sediment supply from the cliffs.
•
To enable an alternative approach to adaptation to coastal change that manages and balances
the conflicting issues for coastal management on this part of the North Norfolk coast.
The impacts of a Sandscaping scheme (including any mitigation and/or compensation) will
need to be acceptable to the regulators, including the planning authority and environmental
stakeholders.
One of the key benefits of a large-scale beach nourishment scheme where nourishment is
undertaken only every 20-25 years is that it reduces the frequency of disturbance of habitats
at the dredging site and at the foreshore compared with traditional beach nourishment (three
to five year nourishment cycle). Reduced frequency of nourishment would also reduce the
impacts on fisheries.
The presence of a substantial beach at the toe of the natural cliffs in front of or to the north of
the Bacton Gas Terminal Complex would minimise cliff erosion due to undercutting of the toe
and subsequent slumping or shear failure. This will reduce the input of sediment into the
system, estimated to be about 5,000m3 year from the 1800m frontage. This volume would
be accounted for in the design of the Sandscaping scheme.
A beach crest level equivalent to or slightly above the design water level would not
significantly reduce the erosive capacity of the cliffs in terms of continuing exposure of the
geological features, as erosion due to weathering would not be prevented. Therefore a
Sandscaping scheme would not prevent longer term erosion of the cliffs, as the enhanced
beach could be removed should future coastal management priorities change. The only
exception to this would be if the Gas Terminal operators required additional protection to any
of their assets within the cliff face should they be at risk from erosion due to weathering, as
part of achieving an ‘As Low As Reasonably Practicable’ standard of protection. This is not a
function of any coast protection provided by Sandscaping, rather an aspect that needs to be
considered in the context of providing appropriate protection to critical national infrastructure.
The sediment used for Sandscaping nourishment should be of a similar size and type to
the existing beach material. It is expected that suitably sized sediment would be available
from the nearby offshore sandbanks, as such material is currently used to nourish the
beaches along the Happisburgh to Winterton frontage.
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5.5
Summary of Design Criteria and Design Assumptions
Table 5.3 Summary of Design Criteria and Design Assumptions
Criteria / Assumption
Description / Value
Effective Life of Scheme:
•
To optimise the effective life of any nourishment programme, considering the associated timescales for downdrift
impacts (i.e. when will upstream nourishment reach Cart Gap?).
Design Life:
50 years. Assume that management policy reverts to SMP Policy after 50 years.
Rate of sediment movement: 800m/year
Economic appraisal period:
100 years, for consistency with SMP and Coastal Study
Nourishment frequency
25 years
Risk Management – Bacton Gas Terminal Complex
•
To provide protection to the assets associated with the Bacton Gas Terminal Complex (nationally important
critical infrastructure with a direct asset value of over £200m) for at least 50 years.
•
To enable an alternative approach to adaptation to coastal change that manages and balances the conflicting
issues for coastal management on this part of the North Norfolk coast.
Options considered
i.
Sandscaping nourishment along the Gas Terminal frontage sufficient to achieve
SMP policy (Hold the Line to 50 years), followed by construction of hard defences
after Year 50.
ii.
Sandscaping nourishment further south (Bacton to Walcott frontage) would require
additional investment in hard defences at the toe of the cliffs.
Design standard for ‘SMP
policy’ Scenario:
1:10,000 years
2065 Design water level
4.36 mAOD (includes 0.40m allowance for sea level rise due to climate change)
Design beach crest level
+5.0mAOD
Minimum berm width
50m
Risk Management – Bacton, Walcott & Ostend:
•
As a minimum, to maintain the standard of protection currently provided by the defences to the Bacton, Walcott
and Ostend frontage, reducing the risk of failure in the short term (0-20 years), in accordance with SMP policy.
•
To consider opportunities to improve the standard of protection provided to Bacton, Walcott and Ostend frontage,
to reduce the risk of defence failure in the medium term (up to 50 years).
•
To enable an alternative approach to adaptation to coastal change that manages and balances the conflicting
issues for coastal management on this part of the North Norfolk coast.
Options considered
i.
Sandscaping nourishment to Gas Terminal frontage, assumed to extend the life of
the Bacton, Walcott and Ostend defences by 20 years.
ii.
Sandscaping nourishment that improves the standard of the defences throughout
the Bacton, Walcott and Ostend frontage to ‘Hold the Line’ for 50 years.
Nourishment volume to
account for beach erosion
30,000m3/year
Minimum nourishment
volume for 1:50 year
standard of protection
900,000m3, over 3km frontage
Risk Management – Mundesley
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected elsewhere, e.g. Cart Gap
(nourishment programme) and Mundesley (proposed HtL scheme).
Options considered
i.
Sandscaping nourishment to the Gas Terminal frontage would extend the life of
the Mundesley defences by 20 years.
ii.
Sandscaping nourishment to the Bacton, Walcott and Ostend frontage would
require investment in defence improvements at Mundesley equivalent to that
required with the SMP management policy.
Risk Management – Ostend to Eccles:
•
To enable an alternative approach to adaptation to coastal change that manages and balances the conflicting
issues for coastal management on this part of the North Norfolk coast.
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Criteria / Assumption
Description / Value
Impact on erosion and
flood risk
Assume erosion & flooding damages and associated investment is delayed by 20 years
Risk Management – Eccles to Winterton:
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected elsewhere, e.g. Cart Gap
(nourishment programme) and Mundesley (proposed HtL scheme).
•
To enable an alternative approach to adaptation to coastal change that manages and balances the conflicting
issues for coastal management on this part of the North Norfolk coast.
Assumptions
Sandscaping nourishment will achieve a sediment flux at Cart Gap equivalent (as a
minimum) to existing EA nourishment, i.e. no requirement for additional nourishment
and associated costs.
Volume of Sediment:
•
Sandscaping nourishment to be of sufficient size to influence the coastal processes, so that beach levels are
maintained at key locations on adjacent parts of the coast whilst maintaining and potentially enhancing sediment
drift along the coast.
Longshore sediment
transport deficit
130,000m3/year
Nourishment volume to
account for cliff erosion
5,000m3/year
Sacrificial/buffer volume
25% of total, for first nourishment campaign.
Total nourishment volume
5,156,250 m3 – Phase 1 nourishment
4,125,000 m3 – Phase 2 nourishment, after 25 years
Nourishment Location, Plan Shape and Profile:
•
Sandscaping nourishment to be of sufficient size to influence the coastal processes, so that beach levels are
maintained at key locations on adjacent parts of the coast whilst maintaining and potentially enhancing sediment
drift along the coast.
•
To deliver risk management efficiencies by offsetting expenditure incurred or expected elsewhere, e.g. Cart Gap
(nourishment programme) and Mundesley (proposed HtL scheme).
Options considered
i.
ii.
Sandscaping adjacent to the Bacton Gas Terminal complex as the principal means
of erosion risk management to this frontage.
Sandscaping at the northern end of the Bacton, Walcott and Ostend frontage, with
a more limited quantity of nourishment material extending northwards as
protection to the Gas Terminal in combination with smaller-scale hard defences.
Beach slope
1:30
Crest berm width
Maximum width 150m to 200m
Minimum width 50m
Natural Environment:
•
To minimise impacts on the natural environment, including foreshore and nearshore habitats, geological features
and fisheries.
•
To optimise the balance between the presence of a beach that provides protection against erosion, and the
reduction of sediment supply from the cliffs.
•
To enable an alternative approach to adaptation to coastal change that manages and balances the conflicting
issues for coastal management on this part of the North Norfolk coast.
Consents
The impacts of the scheme (including any mitigation and/or compensation) will need to
be acceptable to the regulators (including the planning authority and environmental
stakeholders).
Cliff erosion
Beach crest level at or slightly above the design water level will not significantly reduce
the erosive capacity of the cliffs in terms of continuing exposure of the geological
features, and longer term erosion of the cliffs will not be prevented. Reduction in
sediment input from cliff erosion accounted for in the design of the Sandscaping
scheme.
Sediment type and grain
size
The sediment used for Sandscaping nourishment should be of a similar size and type to
the existing beach material. Suitably sized sediment is expected to be available from
nearby offshore sandbanks.
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6
BENEFITS ASSESSMENT
6.1
Approach
Sandscaping is a strategic-level approach affecting more than one policy unit within the
strategy area. Therefore the benefits and costs of implementing large-scale nourishment
need to be assessed over the full extent of the strategy area (Cromer to Winterton, Policy
Units 6.05 to 6.13).
Consequently the Do Nothing and Do Something (SMP policy) benefits as determined
by the Cromer to Winterton Strategy will be summed for all policy units for comparison
with Do Something (Sandscaping). For those policy areas north of Mundesley, the cost
of implementing SMP policy via the preferred strategic option will be included in the
assessment of Do Something (Sandscaping).
For the purposes of this feasibility study, a Sandscaping scheme will be assumed to
have a design life of 50 years. This timescale is sufficient to demonstrate commitment
to investment in coast protection infrastructure to enable inward investment to be
encouraged, whilst avoiding very long-term commitments to ongoing capital and
revenue costs. The assessment of scheme benefits will therefore assume that the
management policy reverts to the SMP policy after year 50.
6.2
Coastal Management Scenarios and Impacts
Four potential coastal management policies are considered for the benefits assessment:
A. Do Nothing – baseline scenario against which all damages, benefits and costs
are compared (not considered to be a realistic management option).
B. SMP Policy – coastal management in accordance with SMP policy
C. Sandscaping adjacent to Bacton Gas Terminal Complex
D. Sandscaping along the Bacton, Walcott and Ostend frontage
The expected physical effects and resulting impacts of each of these scenarios are
summarised in Tables 6.1 to 6.4.
Table 6.1 Effects and Impacts of Policy A – Do Nothing
Physical effect
Impacts
Welfare effects (social costs and
benefits)
Cliff and beach erosion
Damage to or loss of property by erosion
(storm events)
Reduced property value
Reduced visitor numbers
Reduced visitor spend (actual spend &
value attributed to a visit)
No investment in infrastructure
Very significant impacts due to loss of
nationally critical infrastructure
No business investment, businesses
relocate
-
Deteriorating appearance of area
-
Negative health & wellbeing impacts on
residents
Increase of cases of illness
Safety implications of failing defences
Maintenance costs to address safety
issues
Beaches and dunes maintained / built
Value of positive habitat creation
Increased frequency of
flooding (overtopping and of
low lying land)
Deteriorating condition of
defences
Feed of sediment downdrift
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Table 6.2 Effects and Impacts of Policy B – SMP Policy
Physical effect
Impacts
Costs and benefits
Protection to Mundesley
(medium term) – erosion
halted
Improvements to defences
Infrastructure costs
Reduced risk of loss of property compared to
Do Nothing scenario
Slower decline in visitor numbers/spend
Increased visitor spend compared to Do
Nothing scenario
Property value sustained at Mundesley
Value increase compared to Do Nothing
scenario
Protection to Gas terminal
(long term)
Reduced sediment feed downdrift, could
impact on dunes and require habitat
creation elsewhere
Cost of habitat creation
Maintain defences at
Bacton & Walcott (short
term)
Continued damage/erosion/flooding risk
at Bacton/Walcott
Risk of erosion and flooding delayed
compared with Do Nothing scenario
Continued safety risks and social impacts
at Bacton/Walcott
No change compared with Do Nothing
scenario
Reduced property value Bacton/Walcott
No change compared with Do Nothing
scenario
Limited business & infrastructure
investment
Limited economic development (e.g. tourism),
no change compared to Do Nothing scenario
Table 6.3 Effects and Impacts of Policy C – Sandscaping adjacent to Bacton Gas Terminal
Physical effect
Impacts
Costs and benefits
Protection to Gas
Terminal (long term)
Large-scale nourishment significantly
reducing risk of erosion
Fewer safety incidents
Bacon/Walcott defences
maintained as present
condition
Continued risk of flooding and failure on
extreme event but improved safety and
social aspects due to significantly reduced
breach risk
Fewer safety incidents
Property value at Bacton /Walcott sustained
Value increase compared to Do Nothing
scenario
Some (limited) potential to increase visitor
numbers
Limited economic development (e.g. tourism)
Potential for signature project to South of
Mundesley
Specific business case associated with this
opportunity
Maintain property value at Mundesley
Value increase compared to Do Nothing
scenario
Could remove need for nourishment at cart
gap
Reduced cost to EA of beach nourishment
Sediment feed could build Horsey dunes
Value of positive habitat creation
Some protection to
Mundesley as sediment is
retained updrift of Gas
Terminal frontage
Sediment feed downdrift
Long term security of gas supply
Table 6.4 Effects and Impacts of Policy D – Sandscaping along the Bacton, Walcott &
Ostend frontage
Physical effect
Impacts
Costs and benefits
Additional investment
needed in order to
provide long-term
protection to gas terminal
Construction of hard defences required
along Gas Terminal frontage
Additional infrastructure costs, but reduced
compared with SMP policy scenario as
healthy beach is maintained
Sediment retained north of Bacton, retaining
a healthy beach in front of the gas terminal
Fewer safety incidents
Long term security of gas supply
Bacon/Walcott defences
enhanced
Protection to Mundesley
(medium term) – erosion
No risk of damage due to flooding or breach
of defences
Value increase compared to Do Nothing
scenario
Significantly improved safety and social
aspects
Fewer safety incidents
Strong potential to increase visitor numbers
and therefore encourage investment
Increased tourism spend
Recovery of property value (Bacton/Walcott)
Value increase compared to Do Nothing
scenario
Additional works would be needed at
Mundesley to achieve SMP policy.
Infrastructure costs
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Physical effect
Impacts
Costs and benefits
halted
Slower decline in visitor numbers/spend
Increased visitor spend compared to Do
Nothing scenario
Sediment feed downdrift
Property value sustained at Mundesley
Value increase compared to NAI scenario
Some ongoing cliff erosion
Less loss of property (increased property
values) compared to Do Nothing scenario
Could remove need for nourishment at Cart
Gap
Reduced cost to EA of beach nourishment
Sediment feed could build Horsey dunes
Value of positive habitat creation
6.3
Flood and Coastal Erosion Risk Management Benefits
6.3.1
Summary of Baseline Data and Information
The primary source of information for the economic assessment of flood and coastal
erosion risk is the Cromer to Winterton Ness Coastal Management Study (Mott MacDonald
for North Norfolk District Council, 2013). Information provided in the Kelling to Lowestoft
Ness Shoreline Management Plan (AECOM, for North Norfolk District Council, 2012), and
the Overstrand to Walcott Strategy Study (2005) is also taken into account.
The economic assessment undertaken as part of the Coastal Management Study was
based on the 2010 Flood and Coastal Erosion Risk Management Appraisal Guidance
(FCERM-AG) and is considered to be in line with Defra and Treasury guidance. It should
be noted however that the assessment considered each policy unit discretely in terms of
damages and benefits, rather than being an overarching assessment of the economic
benefits of the proposed long-term management strategy for the coast between Cromer
and Winterton.
Property benefits due to erosion and flooding were assessed as part of the 2013 Coastal
Study, with property values based on the 2004 Coastal Strategy, updated to 2013
values. Erosion damages to infrastructure were also taken into account, for the Bacton
Gas Terminal Complex, reconstruction of local roads and re-siting and re-routing the
pumping stations at Overstrand and Mundesley.
The 2013 Coastal Study determined potential recreational benefits but excluded these
from the assessment due to the very high influence that the values had on the cost
benefit scores. The study concluded that a more up to date local assessment using the
Contingent Valuation Method is required for an accurate assessment of tourism benefits.
Previous UK coastal strategy studies (e.g. for Clacton-on-Sea) have successfully
included tourism benefits in the economic appraisal of flooding and coastal erosion risk.
6.3.2
Damages and Costs Associated with Policy Units 6.05 to 6.07 (Cromer to Mundesley)
For the purposes of the benefits assessment it is assumed that Sandscaping options will not
impact on the Policy Units north of Mundesley. Therefore the benefits and costs determined
by the 2013 Coastal Study are applied for all Do Something options. For Policy Unit 6.05 and
6.07 (Cromer to Overstrand and Overstrand to Mundesley) the option with the highest Benefit
Cost-Ratio is assumed to be preferred. For Overstrand, where a capital scheme is expected
to be implemented, Option 2 (rock placement) is assumed.
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6.3.3
Damages and Costs Associated with Policy Unit 6.08 (Mundesley)
For implementation of Sandscaping to the Bacton Gas Terminal frontage it is assumed
that sediment will be retained updrift, sustaining and potentially building beach levels to
the Mundesley frontage. This will have a positive impact on the residual life of the coastal
defences to Mundesley. Consequently it is assumed that the risk of failure will be
reduced and that the requirement to invest in defence improvements would be delayed by
20 years.
If Sandscaping was to be implemented further south along the Bacton to Ostend
frontage, it is assumed that updrift benefits of retained sediment will not extend as far as
Mundesley. Therefore investment in defence improvements will be required to the same
timescales as the 2013 Coastal Strategy.
6.3.4
Damages and Costs for Policy Unit 6.10 (Bacton Gas Terminal)
Erosion Damages
Erosion damages associated with failure of the defences to Bacton Gas Terminal are
included in this economic appraisal as a baseline for assessment of potential management
approaches, as for the SMP and Coastal Study. In reality, due to the critical value of this
asset to the nation, works would be undertaken to protect these assets until year 50 as a
minimum.
The 2013 Coastal Study assessed the present value damages due to erosion along the
Gas Terminal frontage as £201.2 million. This is based on an estimated asset value of
£280 million, with damages occurring 10 years after SMP year 0. This asset value is
understood to be based on the estimated direct asset value, and does not include for
consequential losses. To enable clear comparison with the Coastal Study, an equivalent
asset value is used in this study.
Cost of Coast Protection
The 2013 Coastal Study assessed the Present Value costs of protecting the Gas Terminal
to be £5,936,000. This assumed that Option 3 would be implemented, i.e. maximise the
life of the defences then construct low-level rock revetment. The basis of the cost
estimate for the low-level rock revetment is not included in the Coastal Study Report,
however it is assumed that the costs are associated with a 1km frontage length, a design
standard of 1:200 years and a design life of 100 years (consistent with the SMP policy).
Since completion of the 2013 Coastal Study, the condition of the defences to the Bacton
Gas Terminal have deteriorated. The cliffs fronting the Gas Terminal itself (Policy Unit
6.10), and also those to the north of the Terminal Complex (Policy Unit 6.09) have
retreated. Gas Terminal assets are understood to be directly at risk due to erosion of both
of these sections of cliff. Therefore the life of the existing defences cannot be extended
any longer; works to improve the defences over a frontage length of 1800m are needed
within the next few years.
As the Bacton Gas Terminal Complex is nationally critical infrastructure, FCERM-AG
recommends that the minimum costs of protecting the assets should be in included in the
appraisal of the Do Nothing baseline option. These costs were not included in the 2013
Coastal Strategy economic appraisal, but have been taken into account by this study.
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The minimum present value costs based on construction of a 1800m long, 10m high
(crest to toe level) rock revetment have been assessed as £41.1 million. This cost is
based on the current management approach by the terminal operators, and therefore
assumes a design life of 50 years, and a design standard return period of 1:10,000, to
reduce the risk of asset loss due to erosion to ‘As Low As Reasonably Practicable’.
Significant ancillary works would be necessary to protect all associated terminal assets,
as well as decommissioning of the existing timber breastworks to enable construction of
the rock revetment, foreshore rental from The Crown Estate, annual maintenance and
decommissioning of the revetment after 50 years. This cost has also been included for
the Do Something (SMP Policy) option.
The cost of undertaking Sandscaping nourishment has been assessed, allowing for 2
phases of beach nourishment at 25 year intervals, extension to the Gas Terminal surface
water outfall, annual monitoring and rental of the foreshore from The Crown Estate. An
upper bound and a lower bound cost has been estimated, based on information from
beach nourishment schemes along the east coast of England. A 30% contingency
allowance has been included in all costs. Costs have been discounted over the 50 year
appraisal period in accordance with the UK Treasury Green Book (3.5% discount rate
years 0-30, 3.0% discount rate years 31-50). A more detailed breakdown of these costs
is provided in Appendix F.
Table 6.5 Present Value Cost Estimate for Sandscaping Nourishment
Item
Lower Bound
Upper Bound
Beach nourishment
£ 71.8m
£ 112.2m
Outfall extension
£ 0.6m
£
Total Capital Cost
£ 72.4m
£ 120.2m
Foreshore Rental
£ 1.7m
£
2.8m
Monitoring
£ 0.8m
£
0.8m
Total Net Present Value
£ 74.8m
£ 116.5m
0.8m
If a Sandscaping scheme was implemented along the Bacton Gas Terminal frontage,
construction of hard defences would not be required for the life of the Sandscaping
scheme. As the costs associated with the Do Nothing and Do Something (SMP Policy)
options assume protection of the Gas Terminal for 50 years, no further costs are
included for the Gas Terminal frontage beyond 50 years.
With a Sandscaping to the Bacton to Ostend frontage, some protection would be provided
due to updrift retention of sediment. However, additional investment in defences to the
Bacton Gas Terminal frontage would be required to achieve an appropriate standard of
protection. Therefore it is assumed that a 7m high rock revetment would be constructed
along the 1800m frontage to the terminal and the cliffs to the north. The present value
cost of this revetment would be £19.2 million.
6.3.5
Damages and Costs for Policy Unit 6.11 (Bacton, Walcott and Ostend)
For implementation of Sandscaping to the Bacton Gas Terminal frontage it is assumed that
sediment transport downdrift will sustaining and potentially build beach levels to the Bacton
to Ostend frontage. This will have a positive impact on the residual life of the coastal
defences and consequently it is assumed that the requirement to invest in defence
improvements (to reduce the risk of failure by undermining) would be delayed. However, it
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is assumed that there would be a continued risk of damage due to overtopping, and of
defence failure due to an extreme storm event. Taking this risk into account, the onset of
damages is assumed to be delayed by 30 years.
If a Sandscaping with a 50-year life was to be implemented along the Bacton to Ostend
frontage itself, it is assumed that failure of defences and associated onset of damages
would be delayed by 50 years.
Costs associated with Sandscaping to the Bacton, Walcott and Ostend frontage are
assumed to be the same as for a scheme along the Gas Terminal frontage.
6.3.6
Damages and Costs for Policy Unit 6.12 (Ostend to Eccles)
If a Sandscaping scheme was implemented to either the Bacton Gas Terminal or the
Bacton, Walcott and Osted frontage, it is assumed that sediment transport downdrift will
sustain and potentially build beach levels between Ostend and Eccles. Consequently it is
assumed that the requirement to invest in defence improvements would be delayed by 20
years under both Sandscaping scheme options.
6.3.7
Damages and Costs Associated with Eccles to Winterton Frontage
As described in Section 3.1.6, the Eccles to Winterton frontage protects a hinterland
which includes designated sites of international importance. As there is a national legal
requirement to protect these sites, the minimum cost of ensuring their protection should
be included as a cost in assessment of the ‘Do Nothing’ baseline scenario (as for the
Bacton Gas Terminal Complex).
As the Strategy update for this frontage is not yet available, this minimum cost has been
estimated based on information from the 2008 Project Appraisal Report for the
Happisburgh to Winterton Sea Defences Stage 3b Scheme, and from the 2013 Coastal
Study. Based on a 4-year nourishment cycle, 500,000m3 of sand nourishment is
assumed to be required, with a cash cost of about £7million. Foreshore rental costs from
The Crown Estate have not been included in this cost. Nourishment is assumed to be
repeated until year 30, when a managed realignment scheme would be implemented, at
an assumed one-off cost of £25million. This gives a net present value scheme cost of
£55.5million. For the purposes of this study, these costs will also be included against the
Do Something (SMP Policy) scenario.
Do Nothing damages were assessed for the 2008 Stage 3b Scheme PAR based on a 5year appraisal period (until the assumed completion of the Strategy update in 2012),
with a present value of £31.8million. This estimate of damages does not include an
economic valuation of the internationally designated sites. For the purposes of this
study, a conservative estimate of the flood risk damages associated with Policy Unit
6.13 for a 100-year appraisal period has been made, with a present value of £60 million
included in the economic appraisal.
One of the design criteria for a Sandscaping scheme is that nourishment will be of
sufficient quantity and designed so that the sediment feed to Cart Gap will eventually
replace the ongoing programme of beach nourishment. Due to the delay in sediment
travelling to Cart Gap from Bacton, the current nourishment programme would need to
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be continued for about 9 years. It is assumed that a managed realignment scheme, with
a capital cost of £25 million, would be implemented after 50 years.
6.3.8
Summary of Flood and Coastal Erosion Risk Management Benefits and Costs
The damages and costs associated with implementing each scenario in terms of flood
and coastal erosion risk management are summarised for in Tables 6.5 to 6.8 for Policy
Units 6.05 to 6.13.
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Table 6.5 FCRM Damages and Costs – Policy A, Do Nothing
Damages & Costs (£k)
Policy Unit
Physical effect
Strategy
This study
Summary / Notes
Damages
Costs
Damages
Costs
6.05 Cromer to Overstrand
Deteriorating defence condition, cliff and beach erosion
Damages from 2013 Coastal Study
165
-
165
-
6.06 Overstrand
Deteriorating defence condition, cliff and beach erosion
Damages from 2013 Coastal Study
7,673
-
7,673
-
6.07 Overstrand to
Mundesley
Deteriorating defence condition, cliff and beach erosion
Damages from 2013 Coastal Study
4,803
-
4,803
-
Damages from 2013 Coastal Study
20,393
-
20,393
-
Cliff and beach erosion, feeding sediment downdrift
Damages from 2013 Coastal Study
2,824
-
2,824
-
6.10 Bacton Gas Terminal
Deteriorating condition of defences. Cliff and beach
erosion, feeding sediment downdrift
Erosion damages are included here purely as a baseline
for assessment of the benefits of potential management
approaches, as for the SMP and Coastal Study.
However, as the Gas Terminal is Nationally Critical
Infrastructure, works would in fact be undertaken under
any crcumstances to meet the ALARP protection criteria.
The SMP & Coastal Study don’t fully address the current
risks to all Gas Terminal assets. Damages are currently
expected to be realised in 5yrs c.f. 10yrs in the Coastal
Study.
201,219
-
238,264
-
6.11 Bacton, Walcott &
Ostend
Deteriorating condition & ultimate failure of defences.
Limited beach erosion (feed of sediment from updrift).
Feed of sediment downdrift. Increasing frequency of
overtopping, associated property flood damages
Damages from 2013 Coastal Study
10,364
-
10,364
-
6.12 Ostend to Eccles
Cliff erosion, sediment feed downdrift. Beaches build
from sediment feed, reducing cliff erosion in longer term
Damages from 2013 Coastal Study
145
-
145
-
6.13 Eccles to Winterton
Sediment feed from updrift, building beaches and
reducing flood risk
Based on PAR damages (not included in Coastal Study)
-
-
60,000
45,853
247,586
5,936
344,631
86,953
6.08 Mundesley
6.09 Mundesley to Bacton
Gas Terminal
Deteriorating condition & ultimate failure of defences
Cliff and beach erosion, feeding sediment downdrift
Total
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Table 6.6 FCRM Damages and Costs – Policy B, SMP Scenario
Damages & Costs (£k)
Policy Unit
6.05 Cromer to Overstrand
6.06 Overstrand
6.07 Overstrand to Mundesley
6.08 Mundesley
6.09 Mundesley to Bacton Gas
Terminal
6.10 Bacton Gas Terminal
6.11 Bacton, Walcott & Ostend
6.12 Ostend to Eccles
6.13 Eccles to Winterton
Physical effect
Summary
Deteriorating defence condition, cliff and beach erosion
Deteriorating defence condition, cliff and beach erosion
Deteriorating defence condition, cliff and beach erosion
Defences to Mundesley maintained in the medium term (to 50 years), with
investment in hard defences required in the long term. Cliff erosion and
associated sediment feed reduced compared with NAI. Beach erosion could
increase compared with NAI (due to presence of hard defences), maintaining
sediment feed but risking long-term defence condition
Managed realignment in the short term, followed by no active intervention.
Cliff and beach erosion and feeding of sediment downdrift is maintained
Defences to gas terminal maintained in long term (to 100 years), assumed
hard defences to prevent erosion of lower face of cliff. Strategy
underestimated cost of ancillary works associated with protecting the gas
terminal assets. Additional costs included in this assessment to account for
these works (assumed to be regular, small scale sand nourishment). Cliff
erosion and associated sediment feed reduced compared with NAI. Beach
erosion could increase compared with NAI (due to presence of hard
defences). This would maintain a sediment feed downdrift but would
increase maintenance requirements for terminal assets and could risk
deterioration in defence condition in the long term.
Defences to Bacton, Walcott and Ostend sustained in short term (to year
20). Failure of defences in medium term. Beach erosion continues at an
increased rate compared with NAI (due to reduced feed from updrift),
continuing to feed sediment downdrift. Increasing frequency of flooding by
overtopping & associated property damage, similar to NAI
Managed realignment, sustaining cliff erosion and feed of sediment
downdrift. Beach erosion with reduced feed of sediment from updrift
SMP policy is Hold the Line in the long term (to 100 years). Beach erosion
continues due to reduced feed from updrift, requiring ongoing beach
nourishment to sustain the level of protection against flooding.
Total
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Draft Report
Strategy
Damages
This study
Costs
Damages
Damages and costs from 2013 Coastal Study
Damages and costs from 2013 Coastal Study
Damages and costs from 2013 Coastal Study
118
4201
4333
133
1959
1717
118
4201
4333
133
1959
1717
Costs & damages as per 2013 Coastal Study
5,048
2,916
5,048
2,916
Costs & damages as per 2013 Coastal Study
1,726
556
1,726
556
-
5,936
-
41,100
Costs & damages as per 2013 Coastal Study
13,783
6,487
13,783
6,487
Costs & damages as per 2013 Coastal Study
145
3,271
145
3,271
Costs and benefits of implementing SMP
policy not included in Cromer to Winterton
Coastal Study economic assessment. Costs
and damages included here are based on the
economic appraisal from the Happisburgh to
Winterton Stage 3b PAR.
-
-
60,000
45,853
29,354
22,975
89,354
103,992
Damages as per 2013 Coastal Study
Costs based on meeting ALARP design
conditions, for rock revetment over 1800m
length.
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29 January 2015
Table 6.7 FCRM Damages and Costs – Policy C, Sandscaping at Bacton Gas Terminal
Policy Unit
Physical effect
6.05 Cromer to Overstrand
6.06 Overstrand
6.07 Overstrand to Mundesley
Deteriorating defence condition, cliff and beach erosion
Deteriorating defence condition, cliff and beach erosion
Deteriorating defence condition, cliff and beach erosion
Downdrift movement of sand prevented so beaches will
build from sediment feed from updrift. Reduced risk of
failure of defences. Cliff erosion reduced (accounted for in
Sandscaping design)
Nourishment to gas terminal provides some direct protection
to beaches. Sediment feed from updrift will build the
beaches between Mundesley and the terminal Reduced cliff
erosion, limiting downdrift sediment feed (accounted for in
Sandscaping design)
6.08 Mundesley
6.09 Mundesley to Bacton Gas
Terminal
Damages & Costs (£k)
This study (Lower Bound)
Summary
Damages
Costs
Damages and costs from 2013 Coastal Study
118
133
Damages and costs from 2013 Coastal Study
4201
1959
Damages and costs from 2013 Coastal Study
4333
1717
Assume 20yr delay in failure risk & defence
investment
Assume erosion damages are delayed by
50yrs
6.10 Bacton Gas Terminal
Large-scale sand nourishment to gas terminal frontage,
providing erosion protection to all gas terminal assets
located along the shoreline in the long term. Reduced cliff
erosion compared with NAI (some limited ongoing erosion
due to weathering processes). Sand nourishment designed
to achieve continued sediment feed downdrift
Zero erosion damages, as per 2013 Coastal
Study associated with Sandscaping scheme
for 50 years.
Cost of additional works to protect terminal (Do
Nothing/Do Minimum) delayed by the 50 year
life of the Sandscaping Scheme.
6.11 Bacton, Walcott & Ostend
Sediment feed from Sandscaping will build beaches. Failure
of defences (breach risk) delayed by 50 years. Beach
erosion continues to feed sediment downdrift. Continued
(reduced) risk of flooding from overtopping
Assume deterioration in defence condition is
delayed by 50 years, but ongoing risk of
flooding and breach on extreme event
6.12 Ostend to Eccles
Sediment feed from Sandscaping nourishment will build the
beaches
6.13 Eccles to Winterton
Sandscaping nourishment designed to sustain sediment
feed so investment in nourishment to this policy unit is no
longer required
Nourishment expected to provide additional
protection to this section of the coast due to
alongshore transport of sediment. Assume
erosion & flooding damages and associated
investment is delayed by 20 years
Assume flooding damages are not incurred for
the 50 year life of the Sandscaping scheme.
Assume managed realignment implemented in
year 50 at a capital cost of £25m, therefore
zero damages. Assume 2 cycles of
nourishment (£7m cash cost per cycle) are
requried in advance of Sandscaping sediment
reaching Cart Gap.
Total
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This study (Upper Bound)
Damages
Costs
118
133
4201
1959
4333
1717
2,537
1,518
2,537
1,518
341
110
341
110
-
74,784
-
116,518
4,911
2,311
4,911
2,311
1,644
73
-
18,255
-
18,255
16,513
102,430
16,513
144,165
73
1,644
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Table 6.8 FCRM Damages and Costs – Policy D, Sandscaping at Bacton/ Walcott
Damages & Costs
Policy Unit
Physical effect
Summary
This study (Lower
Bound)
This study (Upper
Bound)
Damages
Damages
Costs
Costs
6.05 Cromer to
Overstrand
Deteriorating defence condition, cliff and beach erosion
Damages and costs from 2013 Coastal Study
118
133
118
133
6.06 Overstrand
Deteriorating defence condition, cliff and beach erosion
Damages and costs from 2013 Coastal Study
4,201
1959
4201
1959
6.07 Overstrand to
Mundesley
Deteriorating defence condition, cliff and beach erosion
Damages and costs from 2013 Coastal Study
4,333
1717
4333
1717
6.08 Mundesley
Investment in sea defences required to achieve SMP Policy.
Increased beach levels at Mundesley (downdrift sand
movement prevented). Cliff erosion reduced (accounted for
in Sandscaping design)
Damages & costs as per 2013 Coastal Study
5,048
2,916
5,048
2,916
6.09 Mundesley to
Bacton Gas
Terminal
Sediment feed from updrift will build the beaches between
Mundesley and the terminal. Reduced cliff erosion, limiting
downdrift sediment feed (accounted for in Sandscaping
design)
Assume erosion damages are delayed by 20 years
867
279
867
279
6.10 Bacton Gas
Terminal
Design of Sandscaping achieves protection to gas terminal
assets in the long term, potentially combined with additional
works to base of cliffs. Reduced cliff erosion compared with
NAI (some limited ongoing erosion due to weathering
processes)
Zero erosion damages, as per Strategy. Costs included for smallscale hard defences to gas terminal frontage. Cost of additional
works to protect terminal delayed by the 50 year life of the
Sandscaping Scheme.
-
19,180
-
19,180
6.11 Bacton,
Walcott & Ostend
Large-scale sand nourishment to village frontage, delaying
risk of failure of defences and associated onset of erosion
and flooding damages by 50 years minimum. Sandscaping
designed to achieve continued sediment feed downdrift
Costs associated with Sandscaping scheme. Assume failure of
defences & onset of damages delayed by 50yrs
1,367
74,780
1,367
116,518
6.12 Ostend to
Eccles
Sediment feed from Sandscaping nourishment will build the
beaches
Nourishment expected to provide additional protection to this
section of the coast due to alongshore transport of sediment.
Assume erosion & flooding damages and associated investment is
delayed by 20 years
73
1,644
73
1,644
6.13 Eccles to
Winterton
Sandscaping nourishment designed to sustain sediment
feed from updrift such that additional investment in
nourishment programme for this policy unit is no longer
required
Assume flooding damages are not incurred for the 50 year life of
the Sandscaping scheme. Assume managed realignment
implemented in year 50 at a capital cost of £25m, therefore zero
damages. Assume 2 cycles of nourishment (£7m cash cost per
cycle) are requried in advance of Sandscaping sediment reaching
Cart Gap.
-
18,255
-
18,255
16,007
120,867
16,007
162,601
Total
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6.4
Amenity Benefits
The 2013 Coastal Study assessed the potential recreational benefits of the Do Something
options, in terms of economic loss from reduction in tourism numbers. This loss is not
taken into account in the economic appraisal. In addition, the Coastal Study does not
include measures that would introduce tourism benefits, i.e. increases in the economic
value of tourism due to implementation of the strategy. In the context of the Coastal Study
this approach is considered to be appropriate, as the proposed management options would
not significantly alter the function of the coast and its associated amenity value.
If a Sandscaping scheme was to be undertaken, the amenity value of the beaches would
be significantly improved. Visitor numbers would be expected to increase, in a similar way
as has been seen at Sea Palling since the beach nourishment programme was established
there. In terms of amenity benefits, it should be recognised that Sandscaping is a very
different approach to coastal management, with the potential to deliver a type of amenity
that is not available anywhere else in the UK at present. Whilst any increase in visitor
numbers would include visitors that would have otherwise gone to another part of North
Norfolk, or elsewhere on the East coast of England (transfer of amenity benefits) there
would be additional ‘new’ visitors, resulting in a positive difference to the national economy.
This section assesses various information sources relating to tourism in North Norfolk in
order to determine an appropriate estimate of the amenity benefits that Sandscaping could
deliver.
6.4.1
Summary of Data and Information (Visitor Numbers and Spend)
Various sources of data and information were considered to determine the potential
economic benefits associated with improved tourism amenity due to Sandscaping, and
these are summarised in Table 6.9. The most recent data is shown in bold, which will
be used for this study as far as possible.
Figure 6.1 shows how visitor numbers, associated spend and employment numbers
have changed from 1999 to 2012, indicating the importance of tourism to the economy
of North Norfolk and the ongoing growth of this sector.
7,000,000
£400,000,000
£350,000,000
Staying visitor spend
Day visitor spend
Total value of Tourism
Day visits
6,000,000
5,000,000
£300,000,000
£250,000,000
4,000,000
£200,000,000
3,000,000
£150,000,000
2,000,000
£100,000,000
1,000,000
£50,000,000
£-
Number of Visitors to North Norfolk
Total Value of Tourism in North Norfolk
£450,000,000
1999
2005
2010
2012
Figure 6.1 Change in Visitor Numbers and Spend
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Table 6.9 Summary of Tourism Data and Information
Study
Cromer to Winterton Strategy, Mott
MacDonald for NNDC, 2013
Area covered
Cromer to Winterton
The Economic Impact of the Norfolk
Visitor Economy 2012, The South West
Research company Ltd for NNDC, 2014
NNDC local authority area
(Holkham to Horsey)
Economic Impact of Tourism (2010 results),
Tourism South East for NNDC, 2012
NNDC local authority area
(Holkham to Horsey)
Tourism benefits and impacts analysis in the
North Norfolk Coast AONB. Scott Wilson
for the Norfolk Coast Partnership, 2006
Tourism Sector Study, Scott Wilson for
NNDC, 2005
Cromer to Walcott Strategy, HR Wallingford
for NNDC, 2003
AONB area (Hunstanton to
Bacton Gas Terminal Complex,
and Sea Palling to Winterton)
NNDC local authority area
(Holkham to Horsey)
NNDC local authority area
(Holkham to Horsey)
N Norfolk Sandscaping Feasibility
Draft Report
Findings
Tourist numbers estimated based on ‘Economic Impact of Tourism – North Norfolk 2010’ (Tourism South East,
2010).
Figures used were 693,000 staying visitors* and 5,426,000 day visitors*, with an average spend of £187.29/£37.72
per visitor per visit for staying/day visitors respectively. Assumed 70% of visitors between Cromer and Mundesley,
30% to the south of Mundesley. Up-to-date and local contingent valuation analysis considered to be required.
Damages avoided over 100 years: Overstrand £47.8m; Mundesley £103.5m; Bacton, Walcott & Ostend £25.1m
*Note: based on data given below, these values actually relate to all visitors to NNDC in 2010, rather than visitors to
only the Cromer to Winterton Area.
Staying visitor trips = 571,000; Staying visitor spend = £124.9m; Average staying visitor spend = £218.80
Day visits = 5,948,000; Day visitor spend = £220.2m; Average day visitor spend = £37.00
Other related spend = £19,536,500
*Adjusted visitor related spend (assume 40% of travel costs at trip origin) = £341,279,500
Supplier and income induced spend = £74,675,000
Total value of tourism = £415,954,500
FTE employment = 6,550; Estimated actual employment = 9,146; % of all employment = 23%
Staying visitor trips = 693,000; Staying visitor spend = 129,792,000
Day visits = 5,426,000; Day visitor spend = 204,657,000
Other related spend = £21,047,000
Supplier & income induced spend = £64,096,000
Total value of tourism = £397,271,000
FTE employment = 5,171; % of all employment = 21.7%
Tourism within the North Norfolk AONB has a direct economic value estimated at £132.9 million, with additional
induced/indirect spend increasing this to £163.2m. This spend is estimated to support 3,664 jobs within the Norfolk
Coast economy, equivalent to 16% of the working age population of the AONB.
Tourist expenditure contributes an estimated £357.1million to the economy, underpinning 7,069 FTE jobs. 84% of
these jobs are provided directly as a result of visitor spend activity.
Values used were based on East of England Tourist Board Report for NNDC in 2001, based on 1999 data.
The overall value of tourism to North Norfolk District in 1999 was an estimated £186.4 million.
Approximately £101.3 million (i.e. 54%) was generated by staying visitors and approximately £85.1 million (i.e. 46%)
was generated by day visitors.
Approximately 844,000 trips were made by staying visitors, accounting for approximately 3.9 million nights.
Approximately 4.1 million trips were made by day visitors.
The total expenditure supported an estimated 4,160 full time job equivalents (FTEs)
When part time and seasonal jobs are considered, the tourism industry supports an estimated 5,690 actual jobs
within the North Norfolk District.
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6.4.2
Beach and Car Park Use
North Norfolk District Council data on beach and car park use provides further data
about visitor numbers.
Table 6.10 Beach Visitor Numbers (lifeguard season, mid-May to mid-September)
Beach
2010
2011
2012
2013
Sheringham
38,050
41,273
48,129
46,292
Cromer
52,765
43,214
53,103
59,596
Mundesley
19,400
16,154
21,326
39,894
Sea Palling
41,541
55,675
53,103
43,503
Income from Mundesley Car Park (Gold Road) was £87,395 in 2013/14. Charges are 50p
for 30 minutes, £1.20 per hour or £5.00 per day. Figure 6.2 shows that car park use has
been increasing between 2008 and 2014. Car park use is very seasonal, with off-peak
income equating to 14% of the total income from Mundesley car park in 2013/14. Given
the seasonality of the car park use, it is assumed that the majority of car park users will be
visitors. An average 3-hour stay, with 2 visitors per car, equates to 48,550 visitors using
the car park at Mundesley each year.
Figure 6.2 Car Park Income, Mundesley
6.4.3
Caravan Park Occupancy
The approximate numbers of static caravans on each of the sites within the study area
and the estimate of associated visitor numbers are set out in Table 6.11. Average high
season weekly occupancy (22 weeks from mid-May to mid-September) is assumed to be
70%. Average low season weekly occupancy (20 weeks from mid-March to mid May and
mid-September to end December) is assumed to be 40%. Parks are assumed to be
closed for 10 weeks from early January to mid-March. An average of 3 visitors per
caravan is assumed.
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Table 6.11 Estimated Caravan Park Occupancy
Park
Caravans / chalets
Trimmingham House,
Visitors high season
Visitors low season
Total visitors
179
8,270
4,726
12,996
Mundesley
Kiln Cliffs, Mundesley
246
11,365
6,494
17,859
Red House, Bacton
30
2,442
1,395
3,837
Castaways, Bacton
50
4,070
2,326
6,396
Cable Gap, Bacton
70
5,698
3,257
8,955
9
733
419
1,152
130
10,582
6,047
16,629
35
2,849
1,628
4,477
749
46,009
26,292
72,301
The Leas, Bacton
Rainbows End,
Bacton
Walcott, Walcott
Total
6.4.4
Amenity Value based on Multi-Coloured Manual Method
‘Flood and Coastal Erosion Risk Management – A Manual for Economic Appraisal’, known
as ‘The Multi-Coloured Manual’ (MCM) provides guidance on the assessment of benefits
associated with flood and coastal risk management. The MCM recommends valuing
amenity benefits (and therefore impacts on them) using a “value of enjoyment per adult
visit” (VOE) method. This method would ideally involve a site-specific study into the value
that visitors to place on their enjoyment of a particular area. It is not feasible to carry out
such a study for this project, however, between 1987 and 1990, a contingent valuation
exercise was carried out for Clacton-on-Sea in Esssex. The study is referenced by the
MCM as a significant contribution to the methodology of valuing amenity benefits.
The exercise used professional interviewers to derive the average value of each visit to
Clacton, based on visitors’ ‘willingness to pay’ for a resource. Multiplied by the number of
visitors each year (and discounted over the appraisal period), this value provides the
present amenity value of the frontage. The exercise also assessed the potential change in
this value, in the event of loss/deterioration or improvement of the amenity. Interviewees
were shown artists impressions of the frontage in a deteriorated state, and asked the same
questions about what they would be “willing to pay” for that resource. The amount by which
the total value decreased also included transfer of benefits, so the interviewees were also
asked to consider the alternative locations that they might travel, if the Clacton-on-Sea
frontage was left to deteriorate.
Categories of visitor type were identified. Although it was assumed that all visitor types
would pay the same for a visit, the different types of visitor are associated with different
rates of decrease in willingness to pay value. The visitor types include:
i.
ii.
iii.
Local visitors (from within a 3 mile radius of the frontage)
Day Visitors (who start and finish their journey from their place of residence)
Staying visitors (overnight stay).
Table 6.12 shows the current equivalent ‘willingness to pay’ values, updated to 2015 based
on the Retail Price Index. Also included is the loss to the nation that was assumed in the
2012 Clacton and Holland-on-Sea Flood and Coastal Erosion Risk Management Strategy
for the case where the beach deteriorates so much that it is inaccessible. In this scenario,
it is not appropriate to take the full economic damages as some visitors will choose to go
elsewhere within the country.
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Table 6.12 ‘Willingness to Pay’ Value for Clacton-on-Sea
Value of each
Reduction with beach
Increase due to
Loss to nation when
visit (£/visit)
deterioration (£/visit)
improvement (£/visit)
beach inaccessible
Local visitors
20.95
5.02 (24%)
3.77 (18%)
60%
Day visitors
20.95
3.31 (16%)
2.09 (10%)
30%
Staying visitors
20.95
11.73 (56%)
4.81 (23%)
30%
The approved Clacton Management Strategy included the damages associated with
reduced willingness to pay in its economic appraisal. The potential increase in value
due to amenity improvement was not included. Whilst the amenities available in the
coastal villages between Mundesley and Winterton are clearly different to Clacton-onSea, the scenario of beach erosion is similar to the Do Nothing case in North Norfolk.
6.4.5
Assumptions for this study
Based on the various data sources, we have conservatively estimated that about 25% of
North Norfolk’s total staying visitors (150,000 per year) and 10% of the day visitors
(600,000) visit the coast between Mundesley and Winterton. It is assumed that a
Sandscaping scheme would not have an impact on visitor numbers to the north of
Mundesley. Estimates of visitor numbers have not been distributed across each policy
unit, as it would be expected that visitors would go to more than one place during the
course of their visit.
In the baseline Do Nothing scenario, beach levels will continue to decrease and the
condition of the defences will deteriorate, resulting in defence failure. Based on the
defence condition survey for the 2013 Coastal Management Study, the average year of
failure is assumed to be 2037. It is assumed that the national economic contribution of
30% of all day and staying visitors will be lost at this point.
With an improvement in the quality (including crest level and width) of to the beaches
between Mundesley and Winterton, an increase in visitor numbers would be expected.
As Sandscaping provides a new type of amenity, it is assumed that new visitors would
be attracted to the area, and that current visitors would return more often each year,
resulting in an economic gain to the nation. A reasonable (conservative) estimate is for
an increase in occupancy rates to 90% in peak season, and to 40% in low season, or
approximately a 30% increase in total visitor numbers, i.e. 200,000 staying visitors and
800,000 day visitors each year.
Table 6.13 summarises the expected economic damages and benefits associated with
tourism along the Mundesley to Winterton coast, based on the 2012 values for visitor
spend. Table 6.14 sets out the impact on the benefit cost ratio of a Sandscaping scheme
if amenity damages and benefits are taken into account.
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Table 6.13 Economic Impact of Tourism
Scenario
Present day
Criteria
Day visitors
Visitor numbers
Visitor Spend
Total Spend
Do Nothing
Visitor numbers (30% loss) / year
(loss to nation)
Reduced Spend / year
Sandscaping
Visitor numbers
Staying visitors
600,000
150,000
£37.00
£218.80
-
£22,200,000
£32,820,000
£48,456,000
720,000
-180,000
-45,000
-216,000
£6,660,000
£9,846,000
£14,536,800
800,000
200,000
£29,600,000
£43,760,000
£73,360,000
£7,400,000
£7,876,800
£15,276,800
PV loss (from 2037 to 2115)
£206,058,000
Total Spend
Increase
PV benefit (over 50 years)
6.5
Total
1,000,000
£338,755,000
Natural Environment Benefits
The ‘Do Something’ options set out in the 2013 Coastal Study primarily comprise hard
defences. These options potentially have negative consequences for intertidal habitats
and the protected geological sites compared with the Do Nothing scenario.
Sandscaping would reduce these negative consequences through the reduction in hard
defence construction, and would create additional intertidal habitat as the width of the
beach between the high and low water marks would be increased. Based on an assumed
beach crest level of +5.0mAOD and a beach slope of 1:30, the intertidal beach width
would increase by about 100m.
The Environment Agency’s Partnership funding calculator currently values the creation of
intertidal habitat at £50,000 per hectare. If Sandscaping nourishment were to increase
the beach width over a frontage length of 3km, 30ha of new intertidal habitat would be
created, with a value of £1.5million.
It is possible that the additional nourishment will also act to build the dunes at Horsey.
However, as the Sandscaping nourishment volumes are based on maintaining the
sediment feed at Cart Gap at an equivalent level to the current nourishment programmes,
for the purposes of the economic analysis it is assumed that there will be no net increase.
6.6
Other Social Impacts
Social impacts of the potential management options for the coast from Mundesley to
Walcott include the following:
•
•
•
•
•
•
People’s way of life: how they live, work, play and interact on a day-to-day basis.
The community: its cohesion, stability, character, services and facilities.
Political systems: the extent to which people are able to participate in decisions that
affect their lives, the level of democratisation, and the resources provided for this.
Health and wellbeing: considering physical, mental, social and spiritual wellbeing
Personal and property rights: whether people are economically affected, or
experience personal disadvantage
Fears and aspirations: perceptions about safety, fears about the future of the
community, and their aspirations for their future and the future of their children.
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There is limited information available to support the quantitative economic valuation of
these issues. One option could be to undertake a ‘willingness to pay’ analysis for schemes
that address social impacts. To enable a qualitative comparison, Table 6.14 summarises
the social impacts of the potential ‘Do Something’ management policies. This shows that
Sandscaping would be expected to have significant positive benefits to the social fabric of
the area compared with Do Nothing or the current SMP policy. Investment in coast
protection would secure the medium to long term future of the local community and its
associated features and services. Personal economic impacts would be reduced, and
perceptions about safety and worries about the future would improve. All of these impacts
would be expected to result in improvements to health and wellbeing of residents.
Table 6.14 Potential Social Impacts of Alternative Management Policies
Social Impact
Way of Life
Community
Political
systems
SMP Policy
Uncertain future, meaning potential
changes to daily way of life as facilities,
services and individuals properties
gradually become more at risk.
Sandscaping (Gas Terminal or Bacton/ Walcott)
Current way of life can be maintained.
Negative impacts on community cohesion
due to uncertain future and people moving
away from the area.
Secure future in the medium to long term, reestablishing community and reducing the movement
of residents away from the area.
Potential positive impacts for community
cohesion through joint opposition to SMP
policy.
Lasting positive effects from campaign groups.
Perception that their views are not being
listened to / heard.
Sandscaping immediately adjacent to Bacton and
Walcott villages would be expected to have more
positive social impacts than if the scheme was
implemented at the Gas Terminal.
Significant local authority investment in
communication and new local policy to
account for implement managed
realignment policy.
Sandscaping could encourage investment in
additional local services.
Potential negative impacts of increase in visitors.
Potential changes to community dynamics with
increasing visitor numbers.
Potential to involve residents in scheme development
and any associated infrastructure investments.
Possible frustration regarding changing decisions.
Health and
Wellbeing
Worries over uncertain future and
economic impacts leading to negative
impacts on mental and physical health and
wellbeing.
More secure future in the medium to long term,
reducing stress and associated health impacts.
Personal &
Property rights
Reduced property value and ultimately loss
of property due to coastal erosion and/or
managed realignment.
Potential for property values to recover and increase
due to commitment to coast protection, inward
investment and improved amenity value.
Fears and
aspirations
Fears over uncertain future, no opportunity
to plan for the future
More secure future in the medium to long term,
alleviating fears.
Potential for local business investment by residents.
A further impact that has not been valued to date is the cost to the local authority of
implementing the Shoreline Management Plan policy. These costs are significant, difficult
to predict and reflect many of the issues listed above. To date costs incurred relate to
communication of the policy and addressing residents’ concerns through press and website
articles, local newsletters and public meetings. There have also been costs associated
with making changes to other local policies, such as the planning policy, to account for the
recommendations of the SMP. With investment in continued coast protection, the costs to
date would be sunk costs, but additional investment in communication and community
management would not be incurred.
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6.7
Creating Opportunity
The potential value of opportunities that could be enabled if Sandscaping was to be
implemented in this area is summarised below. There is not sufficient evidence to
assess this value quantitatively; however a qualitative evaluation has been completed.
ARUP are currently undertaking a project for The Crown Estate to assess regeneration
potential associated with possible locations for Sandscaping. The outcomes from this
project should be taken into account in confirming the next steps for this project.
6.7.1
Alternative Approach to Adaptive Coastal Management
A Sandscaping scheme for North Norfolk would immediately achieve a much greater
beach width (currently assumed to be a 200m crest berm width) over a 1km-2km length of
the coast. Over time this would result in improved beach levels from Bacton extending
south to Cart Gap.
In the area where the sand engine is constructed, Sandscaping would deliver a very
different type of amenity to anything currently available in Norfolk, or indeed throughout
the UK at present. A wide beach, potentially with creation of new habitat areas,
introduces an amenity that is complimentary to the wider tourism offer across Norfolk.
As well as providing direct amenity benefits, any inward investment that is enabled by
Sandscaping would also contribute to the broader sustainable development of the area.
A significant benefit of a Sandscaping approach to coastal management is that ultimately
it does not change the long term management policy for adaptive and sustainable coastal
management. In the long term the management objective will continue to be to realign
the coast, as set out in the Shoreline Management Plan. However, by implementing
Sandscaping in the medium term (to 50 years) time is provided during which community
adaptation can be appropriately planned and progressed.
In addition, Sandscaping can be considered to make adaptive management more
acheiveable, in comparison with traditional management that can result in ‘forcing the
hand’ to continue to defend, potentially unsustainably, and without any delivering positive
benefits for communities.
6.7.2
Potential Growth in Tourism, Associated Businesses and Employment
A Pathfinder Project was undertaken in 2011 to develop a Tourism Marketing Plan for
East Norfolk (Overstrand to Horsey). The report recognised that East Norfolk does not
benefit from tourism to the same extent as the rest of North Norfolk, with the risk of
coastal erosion constraining inward investment. The Pathfinder area aims to increase its
share of the North Norfolk tourism market, with the aim of attracting young families and
mature couples and to extend the holiday season.
The Pathfinder project identified that there are currently limited opportunities for visitors
to East Norfolk to spend. The accommodation offer is very traditional (e.g. bed and
breakfast, caravan parks), with a need for alternatives. There are limited wet-weather
leisure alternatives, and no key leisure attraction in this part of North Norfolk, which
could attract day visitors from other parts of Norfolk. Therefore there is strong potential
for a ‘signature project’ if investment interest could be generated. A potential site for a
signature project is the former holiday park site immediately to the south of Mundesley.
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This location would directly benefit from an improved sandy beach if Sandscaping were
to be undertaken adjacent to the Bacton Gas Terminal complex, so Sandscaping could
be a catalyst to progress this opportunity.
There is ongoing double-digit growth in leisure tourism across the UK, therefore it would
be reasonable to assume at least a 5% per annum increase in tourism across North
Norfolk over the next 20 years or more without investment in Sandscaping. This forecast
growth in itself could encourage investment in the area. But at present east Norfolk has
little to attract leisure investors, in a large part due to the risk of coastal erosion.
Transport connectivity is also an issue that needs to be resolved.
Investment in Sandscaping would enhance the quality of the sandy beaches, attracting a
greater number of both day and staying visitors, particularly young families. It would
also demonstrate a commitment to coastal protection between Overstrand and Horsey
in the medium to long term, providing greater security for business investors. It would
also provide a focus for the ongoing marketing efforts of the Pathfinder project.
As set out in Section 6.4, a conservative estimate of the potential increase in visitor
numbers due to Sandscaping results in an increase in annual tourism revenue of over
£15 million. In addition, if the coast between Overstrand and Horsey became more
attractive to visitors, drawing them into the area from other parts of Norfolk, this could
create ‘space’ in the relatively saturated tourism market elsewhere in north Norfolk
(recognising that these areas have a different tourism offer to East Norfolk).
It should be recognised that there could be additional costs to the local authority if
Sandscaping were to be implemented, in order to maximise the opportunity potential.
For example, improvements to transport connectivity would be required such as
additional bus services or new links to the National Coastal Path and National Cycle
Network. The local authority and the Local Enterprise Partnership may need to be
involved in negotiations with potential developers. Local planning policy may need to be
revised to reflect the change in approach to coastal management.
6.7.3
Residential Property Value and Development Potential
Planning policy currently restricts development in this part of North Norfolk, due to the
long term SMP policy of managed realignment. If there were to be commitment to
continued coastal protection for at least 50 years then this would provide the opportunity
to revise planning policy and enable investment in the area, albeit with the need to
recognise that coastal management policy may change in the longer term.
The variation in house prices in Mundesley, Bacton and Walcott over the past 20 years
has been reviewed, and included in Figure 6.3. This shows that house prices in Bacton
and Walcott dropped by about £30,000 on average after 2009. This coincides with the
initial publication of the draft SMP, and local awareness of the medium-term policy for
managed realignment of the Bacton to Walcott coast. Prices in Mundesley, where
defences are proposed to be maintained over a longer period, did not increase but did
not noticeably decrease. Compared to Bacton and Walcott, the variation in house prices
in Mundesley is more consistent with national trends between 2009 and 2014.
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250,000
Value (£)
200,000
150,000
100,000
Mundesley
50,000
Bacton
Walcott
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
2015
Figure 6.3 Average House Prices
If a commitment to protection of the Bacton to Walcott frontage, and an associated
improvement in the beach condition, were to result in house prices recovering to their
pre-2009 levels, this would result in an increase of approximately 20% in the benefits
that could be attributed to the scheme.
6.8
Benefit Cost Ratios
Benefit Cost ratios have been determined based on the assessment of Flood and Coastal
Erosion Risk Management benefits and costs. Sandscaping options are compared
against the Do Nothing and Do Something (SMP Policy) baseline scenarios. Damages
and benefits associated with projected changes in amenity value and habitat creation are
included in this assessment, based on the justifications set out earlier in Section 6, in
accordance with the Environment Agency’s Flood and Costal Risk Management Project
Appraisal Guidance.
Table 6.15 summarises the economic appraisal. An indication of the positive or negative
impact of each option in terms of wider impacts, benefits or opportunity creation is also
included.
This table shows that the Sandscaping options can deliver a benefit cost ratio of a
similar order to implementation of SMP policy, when amenity damages and benefits are
excluded from the analysis. Including these benefits greatly increase the justification for
Sandscaping in comparison with SMP policy.
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Table 6.15 Comparison of Benefit Cost Ratios
Policy
Do Nothing
Do Something, SMP Policy
Damages
Costs
Damages
Benefits
165
-
118
47
6.06 Overstrand
7,673
-
4,201
6.07 Overstrand to Mundesley
4,803
-
4,333
20,393
-
5,048
6.05 Cromer to Overstrand
6.08 Mundesley
6.09 Mundesley to Bacton Gas Terminal
6.10 Bacton Gas Terminal
6.11 Bacton, Walcott & Ostend
6.12 Ostend to Eccles
6.13 Eccles to Winterton
Sub-Total
Sandscaping, Gas Terminal
Costs
Lower
Damages
Benefits
Costs
Costs
Upper
Lower
133
118
47
133
133
118
47
133
133
3,472
1,959
4,201
3,472
1,959
1,959
4,201
3,472
1,959
1,959
470
1,717
4,333
470
1,717
1,717
4,333
470
1,717
1,717
15,345
2,916
2,537
17,856
1,518
1,518
5,048
15,345
2,916
2,916
2,824
-
1,726
1,098
556
341
2,483
110
110
867
1,957
279
279
-
-
238,264
41,100
-
238,264
116,518
74,784
-
238,264
19,180
19,180
10,364
-
13,783
6,487
4,911
5,453
2,311
2,311
1,367
8,997
116,518
74,784
-
3,419
145
-
145
-
3,271
73
72
1,644
1,644
73
72
1,644
1,644
60,000
-
-
60,000
45,853
-
60,000
18,255
18,255
-
60,000
18,255
18,255
344,631
-
29,354
315,277
103,992
16,513
326,101
144,165
102,430
16,007
328,624
162,601
120,867
2.28
3.20
2.02
2.72
5.38
7.24
3.03
206,058
544,813
Habitat creation benefits
544,813
1,500
Benefit/Cost Ratio with amenity & habitat
1,500
5.01
---
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Upper
Benefits
238,264
Amenity damages & benefits
Other economic opportunities
Costs
Damages
Benefit/Cost Ratio
Social impacts
Sandscaping, Bacton to Walcott
Costs
-
+
+
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8.54
++
++
7
CONCLUSIONS AND RECOMMENDATIONS
7.1
Conclusions
This technical Feasibility Study has been undertaken to investigate the viability of
undertaking large-scale beach nourishment (Sandscaping) along part of the North
Norfolk coast between Mundesley and Walcott.
Based on a developed understanding of the coastal processes in the study area,
including analysis of current and future sediment transport rates based on SCAPE
modelling results, an assessment has been made of the quantity of large-scale sand
nourishment that would be required to achieve at least equivalent flood and coastal risk
management outcomes to the current Shoreline Management Plan policy for the area.
The study has also identified where a Sandscaping approach to coastal management
will enable additional benefits to be realised, in terms of enabling an alternative
approach to coastal protection, enhancing the natural environment and providing socioeconomic benefits such as improved quality of life, additional amenity value and
potential for inward investment in the area. Due to the nature of a Sandscaping solution,
feeding sediment along the whole of the coast, protection of the Hold the Line areas
from the SMP also leads to improved protection for the areas in between.
The design criteria for Sandscaping along the coast between Mundesley and Walcott
are summarised in Table 7.1 below.
Table 7.1 Summary of Design Criteria and Assumptions
Criteria / Assumption
Options considered
Design Life:
Description / Value
i.
Sandscaping nourishment along the Gas Terminal frontage
ii.
Sandscaping nourishment further south (Bacton to Walcott frontage)
50 years. Assume that management policy reverts to SMP Policy after 50 years.
Rate of sediment movement: 800m/year
Economic appraisal period:
100 years, for consistency with SMP and Coastal Study
Nourishment frequency
25 years
2065 Design water level
4.36 mAOD (includes 0.40m allowance for sea level rise due to climate change)
Design beach crest level
+5.0mAOD
Crest berm width
Maximum width 150m to 200m
Minimum width 50m
Beach slope
1:30
Nourishment volume to
account for beach erosion
30,000m3/year
Nourishment volume to
account for cliff erosion
5,000m3/year
Longshore sediment
transport deficit
130,000m3/year
Sacrificial/buffer volume
25% of total, for first nourishment campaign.
Total nourishment volume
5,156,250 m3 – Phase 1 nourishment
4,125,000 m3 – Phase 2 nourishment, after 25 years
Other Assumptions
Sandscaping nourishment will achieve a sediment flux at Cart Gap equivalent (as a
minimum) to existing EA nourishment, i.e. no requirement for additional nourishment
and associated costs.
Consents
The impacts of the scheme (including any mitigation and/or compensation) will need
to be acceptable to the regulators (including the planning authority and environmental
stakeholders).
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An economic appraisal has been undertaken of the expected benefits and costs of
Sandscaping, comparing two Sandscaping scenarios against a Do Nothing baseline and
the current SMP policy. This is summarised in Table 6.15.
The economic appraisal shows that if the cost of Sandscaping is close to the assumed
lower bound value, the benefit cost ratio of large-scale nourishment adjacent to Bacton
Gas Terminal is slightly better than that for the current SMP management policy.
Including benefits associated with habitat creation and improved amenity value (increased
visitor numbers) significantly increase the economic justification for Sandscaping.
Table 6.15 shows that the benefit cost ratio for the Sandscaping options is strongly
dependant on realising the benefits associated with the Eccles to Winterton frontage, i.e.
Sandscaping nourishment would offset the current cost to the Environment Agency of
four-yearly nourishment campaigns.
7.2
Uncertainties
This feasibility study has demonstrated that Sandscaping could be a viable approach to
coastal management for north east Norfolk, both technically and economically. However,
a number of uncertainties remain. The key uncertainties in the design criteria, and
consequently the economic appraisal, relate to the quantity of sediment required and the
behaviour of the nourishment material once it is placed on the beach.
The assessment of sediment transport deficit relies primarily on the outputs from the
SCAPE modelling, although the results do correlate with other sediment transport
analyses for the North Norfolk coast. The quantity of material required could vary by
+/-40,000m3/year, or 1,000,000m3 over 25 years. This uncertainty is accounted for in
the cost estimate for Sandscaping, with a sacrificial volume included in the quantities for
the first nourishment campaign.
The design profile and associated cross-sectional volume of sediment that is required at
the nourishment location will depend on the beach profile at the time of placing the sand.
Bathymetric surveys at the beach profile monitoring locations were last undertaken in
2002. Therefore there is uncertainty in terms of the frontage length that could be
nourished by a total volume of about 5 million m3.
The SCAPE modelling and beach profile analysis indicate that it could take between 5
and 20 years for sediment to move from the nourishment site to Cart Gap and beyond.
This uncertainty can be managed through monitoring and by continuing the four-yearly
nourishment campaigns along the Happisburgh to Winterton frontage. However, this
could increase the total scheme costs by about £15 million.
The amount of material that is transported offshore and alongshore will vary seasonally
depending on incident wave and tidal conditions. Therefore a large volume of sediment
could ‘disappear’ from the nourishment site in one storm, and may not move back onshore
for some time. This could create issues in terms of public and stakeholder perception of
the performance of the sand engine, requiring good communication and reassurance that
sediment is still within the coastal system and is doing what it is expected to do.
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The perception that Sandscaping is a high risk approach to coastal management
(particularly in terms of risk of damage to the Gas Terminal and natural environment
assets) will need to be overcome in order to gain consent for scheme implementation
from the statutory stakeholders. Risk ownership for the operational phase of the
scheme would also need to be addressed through the development of an appropriate
approach to funding and financing.
The economic appraisal includes a number of assumptions regarding coastal erosion
damages and associated benefits. For the Happisburgh to Winterton frontage, the value
of benefits has been estimated based on the 2013 Coastal Study and the 2008 Stage 3b
PAR. Up-to-date information from the ongoing Strategy Review, ideally including
valuation of the natural environment benefits, would improve confidence in the findings
of the economic appraisal. For the Bacton Gas Terminal complex, the asset value used
in the 2013 Coastal Study has been included in the economic appraisal. This value
does not include consequential damages that would result from erosion damages to the
terminal assets (disruption or loss of gas supply).
The assessment of potential regeneration benefits could be enhanced by incorporating
the emerging results of Arup’s ongoing work as part of the Sandscaping partnership.
Notwithstanding these uncertainties, the study is considered to have demonstrated the
technical and economic viability of a Sandscaping approach to management of this part
of the North Norfolk coast.
7.3
Recommendations for Next Steps
The recommended next steps for progressing development and implementation of a
Sandscaping scheme in North Norfolk are summarised below. These next steps primarily
relate to resolution of the uncertainties described in Section 7.2. When available, the
outcomes from ARUP’s project for The Crown Estate to assess regeneration potential
associated with possible Sandscaping locations should also be taken into account in
confirming the next steps. The Bacton to Walcott study currently being initiated jointly
with the Environment Agency and the Bacton Terminal Companies could form a vehicle
for achieving some of these next steps.
Further discussions will be needed with statutory stakeholders, to determine the
requirements for consenting to a Sandscaping scheme. A statutory Environmental
Impact Assessment (EIA) would be required, which would need to include a robust
evidence base to demonstrate that negative environmental impacts can be minimised or
appropriately mitigated.
It is expected that numerical modelling of sediment transport would be required by the
statutory stakeholders to inform the EIA process. Such modelling could also be used to
develop and refine the preferred location, plan shape and profile for the sand nourishment.
It is recommended that a bathymetric survey of the study area is undertaken as part of this
modelling programme.
Discussions with stakeholders (including the Environment Agency, the Bacton Terminal
Companies North Norfolk District Council and New Anglia Local Enterprise Partnership)
should also address how the scheme could be financed and the associated approach to
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risk management. Such discussions would also cover funding issues relating to
opportunity creation, e.g. the potential for investment in a ‘signature’ leisure attraction
project, and other investment that might be needed to leverage the potential of the
Sandscaping scheme in terms of amenity and other socio-economic improvements.
These discussions will enable the costs and timescales associated with the design and
consents process to be determined.
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8
REFERENCES
A New Alternative to Saving Our Beaches from Sea-Level Rise: The Sand Engine,
M.J.F. Stive et. al., Journal of Coastal Research, 2013
An Introduction to Coastal Defence, North Norfolk District Council, 2009
An Introduction to the North Norfolk Coastal Environment, North Norfolk District Council,
2009
Background Information (Economy), North Norfolk District Council,
http://www.northnorfolk.org/planning/249.asp
Car Park Management and Pricing Review 2013/14, North Norfolk District Council, 2014
Cliff and Shore Erosion under Accelerating Sea Level Rise, Results of Case Study
Analysis, Report – SC120017/R, Environment Agency, 2014
Coastal Planning in North Norfolk – Information Sheet No. 1, North Norfolk District
Council, 2007
Coastal Protection in North Norfolk, North Norfolk District Council, 2001
Coastal Trends Report North-East Norfolk and North Suffolk (Subcell 3b - Kelling to
Lowestoft) Environment Agency, 2008
Communities at risk - planning for a future with a changing coastline, North Norfolk
District Council, 2009
Cromer to Winterton Ness Coastal Management Study, Mott MacDonald for North
Norfolk District Council, 2013
Economic Impact of Tourism, North Norfolk District 2010 Results, Tourism South East,
undated
Find out more about our coast, North Norfolk District Council
http://www.northnorfolk.org/environment/18015.asp
Flood and Coastal Erosion Risk Management – A Manual for Economic Appraisal,
Middlesex University, 2013
Flood and Coastal Erosion Risk Management Appraisal Guidance (FCERM-AG),
Environment Agency, 2010
Happisburgh to Winterton Sea Defences Stage 3b Project Appraisal Report,
Environment Agency, 2008
Integrated analysis of coastal risks, R.J. Dawson et. al. (Tyndall Centre for Climate
Research), undated
Kelling to Lowestoft Ness Shoreline Management Plan, AECOM for North Norfolk
Coastal Management Group, 2012
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Marine Aggregate Regional Environmental Assessment: Coastal Characterisation,
Technical Note TN-DDR4472-02, HR Wallingford for Marine Aggregate Dredging
Association, 2010
Modelling the impacts of climate change on an eroding coast over the 21st Century,
Tyndall Centre for Climate Research, 2006
North Norfolk Aerial Photographs, Environment Agency, 1996 – 2014
North Norfolk Beach Profile Monitoring, Profiles N066 to N079, Environment Agency,
1996 – 2014
North Norfolk Development Control Guidance – Development and Coastal Erosion,
North Norfolk District Council, 2009
http://www.northnorfolk.org/files/Coastal_Erosion_Development_Control_Guidance.pdf
Ostend to Cart Gap Strategy Study, HR Wallingford for North Norfolk District Council, 2001
Overstrand to Walcott Littoral Sediment Processes Report EX 4692, HR Wallingford for
North Norfolk District Council, 2003
Overstrand to Walcott Strategy Study, HR Wallingford for North Norfolk District Council,
2005
Retail and Commercial Leisure Study, DTZ for North Norfolk District Council, 2005
Sand Banks, Sand Transport and Offshore Windfarms, N.H.Kenyon and B. Cooper,
2005
Sand Engine: Background and Design of a Mega-Nourishment Pilot in The Netherlands,
J.P.M. Mulder and P.K. Tonnon
Sheringham to Lowestoft Shoreline Management Plan Subcell 3b Phase 2, Halcrow for
North Norfolk Coastal Management Group, 1996
Southern North Sea Sediment Transport Study, Phase 2, Sediment Transport Report,
HR Wallingford and Posford Haskoning, 2002
Technical Note, Happisburgh (Eccles) to Winterton Winter 2008 to Winter 2012 Beach
Survey Vol. Analysis, Environment Agency, 2012
The Economic Impact of the Norfolk Visitor Economy 2012, COOL programme / The
South West Research Company Ltd., 2014
Tourism Benefits and Impacts Analysis in the North Norfolk Area of Outstanding Natural
Beauty, Scott Wilson for North Norfolk Coastal Partnership, 2006
Tourism Marketing Framework and Action Plan for East Norfolk Pathfinder Area
Final Report, Blue Sail, 2011
Tourism Sector Study, Scott Wilson for North Norfolk Coastal Partnership, 2005
Towards an integrated coastal sediment dynamics and shoreline response simulator,
Tydall Centre for Climate Research, 2005
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Appendix A
Introduction to the North Norfolk Coastal Environment
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Appendix B
Extract from Shoreline Management Plan – Baseline
Processes Understanding
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Appendix C
Analysis of SCAPE Modelling
North Norfolk Sandscaping
Feasibility Study
The Crown Estate
29 January 2015
Draft Report
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North Norfolk Sandscaping: Analysis of
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INTRODUCTION
The coast of northeast Norfolk between Cromer and Happisburgh is an almost
continuous line of glacial tills cliffs. Net sediment transport is to the southeast and the
potential for transport increases with distance south as the coastline curves from east
aligned to southeast aligned. The average height of the cliffs is approximately 20m,
reaching a maximum of approximately 60m at Trimingham and to the east of Cromer.
The objectives of this report are to provide a review of potential future estimates of
longshore sediment transport rates using the results from SCAPE modelling along this
coast. The SCAPE model was run between Cley-next-the-Sea and Winterton Ness to
predict the geomorphological response of the coast between Cromer and Happisburgh
to a ‘Do Nothing’ (Management Scenario 1) and ‘SMP Policy 6’ (Management Scenario
2). Management Scenario 1 represents a general policy of not intervening with the future
failure of coastal structures, whilst Management Scenario 2 represents implementation
of the preferred policies of the recent Shoreline Management Plan review. These
scenarios were represented in the model by ‘switching off’ the seawalls, revetments and
groynes, in particular places at specified years. The reported outputs from the model
included projections of longshore sediment transport rates at Cart Gap (where the cliffs
meet low-lying land). The difference between the two scenarios in terms of residual life
of defences is shown in Figure 1.2, based on minimum residual life.
As part of this project, further data produced as outputs of the SCAPE model (but not
previously published) have been analysed within the context of possible sandscaping in
the area between Mundesley and Bacton. These data include predicted longshore
sediment transport rates at more locations between Trimingham and Sea Palling, for
each year between 2013 and 2120 for Management Scenarios 1 and 2. These data
have been used to determine how the rates are predicted to differ for each scenario,
and, through interpretation of this, what the implications would be for a sand engine at
Bacton.
To run the model, the coast was represented by 500m-long segments. Within each
segment the shore profile, beach volume and wave conditions are assumed to be
constant. The model was run up to the year 2120 using the two management scenarios
and under predicted climate change projections (represented in the model through
effects on sea-level rise and wave activity). Data has been analysed at the following
locations:
•
•
•
•
•
•
•
•
Trimingham (Sections 56 to 58);
Mundesley (Sections 48 to 53);
Bacton (Sections 43 to 45);
Walcott (Sections 35 to 37);
Happisburgh (Sections 30 to 32);
Cart Gap (Section 29);
Eccles (Sections 25 to 27); and
Sea Palling (Sections 19 and 20).
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Figure 1.2. Relative residual life of defences under scenarios 1 and 2.
MANAGEMENT SCENARIO 1
The results of the SCAPE model for 2013 predict net sediment transport rates between
88,000m3/year and 206,000m3/year to the south.
The lowest rate occurs at Trimingham (88,000m3/year) increasing through Mundesley to
Walcott (119,000-134,000m3/year) decreasing at Happisburgh to Eccles (100,000105,000m3/year) before increasing significantly at Sea Palling (206,000m3/year) (Table
2.1 and Figure 2.1).
Through to 2110 on a decadal basis, the predicted sediment transport rates increase
consistently to 2060 (444,000-521,000m3/year at most locations and 317,000m3/year at
Trimingham), before continuing to increase but at a much slower rate post 2060. At
2110, the predicted longshore transport rates at Trimingham are lowest
(346,000m3/year), then Mundesley (478,000m3/year), with sites further south (Bacton to
Sea Palling) between 509,000m3/year and 526,000m3/year.
Significant increases in sediment transport are predicted to occur in the 2020s decade
north of Cart Gap, correlating with the assumed end of the residual life of many
structures between Mundesley and Happisburgh.
Table 2.1. Predicted longshore sediment transport rates predicted by SCAPE from
2013 to 2110 for Management Scenario 1
Year
Location
2013
2020
2030
2040
2050
2060
2070
2080
2090
2100
2110
Trimingham
88189
110525
234812
243567
293527
317375
328157
294010
329316
341408
345541
Mundesley
128310
167619
392824
376178
406702
444338
452136
422977
464086
473854
477576
Bacton
119461
160047
473079
437633
461061
503125
500546
473485
508379
522001
514075
Walcott
134047
135701
464519
446708
474181
518457
505119
489195
510646
523762
519869
Happisburgh
105033
188209
400837
413637
457236
510364
500178
484465
506549
517488
514513
Cart Gap
103961
210359
372665
394796
446797
505768
497122
482274
503776
515109
512454
Eccles
100350
252074
331619
370896
435681
499282
494424
481374
502128
514567
509330
Sea Palling
205733
115082
278898
370757
420646
521471
523849
499381
528912
501537
526468
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-
2000
2020
2040
2060
2080
2100
(100,000.00)
(200,000.00)
(300,000.00)
(400,000.00)
(500,000.00)
(600,000.00)
Sea Palling
Walcott
Eccles
Bacton
Cart Gap
Mundesley
Happisburgh
Trimingham
Figure 2.1. Predicted longshore sediment transport rates predicted by SCAPE
from 2013 to 2110 for Management Scenario 1
MANAGEMENT SCENARIO 2
The results of the SCAPE model for 2013 predict net sediment transport rates between
97,000m3/year and 210,000m3/year to the south. The lowest predicted rate occurs at
Trimingham (97,000m3/year) increasing south through Mundesley to Walcott (121,000134,000m3/year), further increasing at Happisburgh (210,000m3/year), then decreasing
at Cart Gap (166,000m3/year) and Eccles (100,000m3/year) before increasing again at
Sea Palling (207,000m3/year) (Table 2.2 and Figure 2.2). Into the future, the predicted
sediment transport rates increase to about 2070 but at a lower rate than Management
Scenario 1. Anomalously high rates occur at Walcott during the 2030s decade when the
residual life of the coast protection structures is reached, as shown in Figure 1.2.
At 2110, the predicted longshore transport rates at Trimingham are lowest
(306,000m3/year), with the highest rates between Bacton and Cart Gap (508,000522,000m3/year). Predicted rates at Mundesley, Eccles and Sea Palling are
451,000m3/year, 495,000m3/year and 431,000m3/year, respectively.
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2120
Table 2.2. Predicted longshore sediment transport rates predicted by SCAPE from
2013 to 2110 for Management Scenario 2
Year
Location
2013
2020
2030
2040
2050
2060
2070
2080
2090
2100
2110
Trimingham
97118
147869
222045
245053
260172
300796
317773
298617
290625
319269
306047
Mundesley
133817
180204
281196
285359
290250
352562
526804
470705
453109
475621
450623
Bacton
140375
196213
301820
342217
322916
382773
612585
557068
520619
535066
510986
Walcott
120551
142276
253397
482906
374039
412340
477854
523118
511551
521700
508602
Happisburgh
210155
173288
234083
381039
392541
433496
435777
467371
471015
492921
508487
Cart Gap
165634
182151
226831
350119
387441
439508
432280
451100
457585
484332
522241
Eccles
100308
186352
223407
313642
377693
443493
432308
439002
442591
470516
494802
Sea Palling
206638
167635
194147
255311
369793
398215
448968
432040
401986
463460
430544
2000
-50000
2020
2040
2060
2080
2100
2120
-150000
-250000
-350000
-450000
-550000
-650000
Sea Palling
Happisburgh
Mundesley
Eccles
Walcott
Trimingham
Cart Gap
Bacton
Figure 2.2. Predicted longshore sediment transport rates predicted by SCAPE
from 2013 to 2110 for Management Scenario 2
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IMPLICATIONS FOR SANDSCAPING AT BACTON
In order to determine how the potential management scenarios at Mundesley have
implications for a sand engine at Bacton, and for the coast further south at Walcott, the
predicted longshore sediment transport rates for each scenario are compared at each of
these three locations. The time line of assumed structure failure for both scenarios is
presented in Table 4.1.
Table 4.1. Time line of assumed structure failure for Management Scenarios 1 and
2 at Mundesley, Bacton and Walcott
Seawall
Location
Revetment
Groyne
Section
MS1
MS2
MS1
MS2
MS1
MS2
53
-
2022-2032
2022-2032
2020-2027
2020-2027
52
-
2027-2037
2027-2037
2020-2027
2020-2027
51
-
2027-2037
2027-2037
2020-2027
2020-2027
50
-
2020-2027
2063-2070
2020-2027
2063-2070
49
2020-2027
2063-2070
2021-2027
2064-2070
48
2020-2027
2063-2070
2021-2027
2064-2070
Mundesley
Bacton
Walcott
45
2027-2032
2027-2032
2020-2027
2020-2027
44
2027-2032
2070-2075
2020-2027
2063-2070
43
2024-2032
2067-2075
2020-2027
2063-2070
37
2022-2037
2035-2050
2019-2025
2032-2038
36
2022-2037
2035-2050
2017-2022
2030-2035
2018-2025
2031-2038
35
2024-2032
2037-2045
Comparison of Management Scenarios 1 and 2 at Mundesley
In Management Scenario 1, the residual lives of the seawall (Sections 48 and 49) and
groynes (Sections 48 to 53) at Mundesley are assumed to be 2020 (minimum) to 2027
(maximum) (Table 4.1). The residual life of the revetment (Sections 50 to 53) is
assumed to be 2020 to 2037. Further north at Trimingham, all the structures are
assumed to fail at sometime between 2012 and 2027, as shown earlier in Figure 1.2.
In Management Scenario 2, the seawall (Sections 48 and 49), groynes (Sections 48 to
50) and revetment (Section 50) are assumed to fail much later than Management
Scenario 1, between 2063 and 2070. The groynes and revetment further north (Sections
51 to 53) are assumed to fail between 2020 and 2037.
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Figure 4.1 shows the predicted differences in longshore sediment transport rates
between Management Scenario 1 and Management Scenario 2 at Mundesley (Sections
48 to 53). Positive values indicate that rates predicted for Management Scenario 1 are
higher than Management Scenario 2. The data shows that between 2013 and the mid2020s, the rates for Management Scenario 1 and Management Scenario 2 are broadly
comparable. However, in the mid-2020s, the predicted sediment transport rates for
Management Scenario 1 rapidly become much higher than for Management Scenario 2
(Figure 4.1). This increase in rate for Management Scenario 1 coincides with the failure
of the structures at Mundesley (and Trimingham) under this scenario. The largest shift in
difference occurs at Sections 48 and 49 where the seawall fails in Management
Scenario 1. Under Management Scenario 2, the key sea wall and groyne structures are
still in place. The maximum predicted difference in longshore sediment transport rate
between the two scenarios is 233,000m3/year at Section 48 in 2028.
The longshore sediment transport rates for Management Scenario 1 continue to be
much higher than for Management Scenario 2 until the mid-2060s when the situation is
quickly reversed, particularly at Sections 48 and 49, south Mundesley(Figure 4.1). The
reversal continues until the mid-2080s when the rates for each scenario become broadly
similar again. The reversal in trend coincides with the failure of the seawall and parts of
the groynes and revetment structures at Mundesley between 2063 and 2070 as part of
Management Scenario 2.
Overall, between the mid-2020s and the mid-2060s, when the predicted rates for
Management Scenario 1 are higher than for Management Scenario 2, there is a gradual
increase in the predicted difference in average longshore sediment transport rates from
north (Section 53; 65,000m3/year) to south (Section 48; 130,000m3/year) (Figure 4.1
and Table 4.2).
Although some of the change in drift may be accounted for in the changing orientation of
the shoreline, in part, this might also suggest an incremental increase in supply from the
cliffs between each section as defences are lost. The supply potentially increases by
around 13,000m3/year/ cell, relatively consistently, across the frontage, accounting for
some 65,000m3/year additional supply from the Mundesley frontage.
Table 4.2. Differences in predicted longshore sediment transport rates between
Management Scenarios 1 and 2 for the period 2025 and 2066 at Mundesley.
Positive values indicate that rates predicted for Management Scenario 1 are
higher than Management Scenario 2
Difference
Section 48 (S)
Section 49
Section 50
Section 51
Section 52
Section 53 (N)
Minimum
84,000
70,000
31,000
16,000
-2,000
3,000
Maximum
233,000
207,000
135,000
114,000
120,000
126,000
Average
130,000
122,000
104,000
85,000
73,000
65,000
(m3/year)
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250,000.00
200,000.00
150,000.00
100,000.00
48
49
50,000.00
50
51
2010
2030
2050
2070
2090
2110
52
53
(50,000.00)
(100,000.00)
(150,000.00)
(200,000.00)
Figure 4.1. Differences in predicted longshore sediment transport rates between Management Scenarios 1 and 2 for the period 2013 to 2120
at Mundesley. Positive values indicate that rates predicted for Management Scenario 1 are higher than Management Scenario 2
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Comparison of Management Scenarios 1 and 2 at Bacton
The sequencing of structure failure at Bacton (Sections 43 to 45) is generally similar to
that at Mundesley (Table 4.1). The structures in Management Scenario 1 are assumed
to fail between 2020 and 2032 and those for Management Scenario 2 (Sections 43 and
44) between 2063 and 2075, although the revetment and groyne at Section 45 are
assumed to fail between 2020 and 2027 (in Management Scenario 2).
Structures between Mundesley and Bacton are all assumed to fail between 2020 and
2032 for both scenarios. The distance from Mundesley to Bacton terminal is about 3km.
The similar timings of structure residual life result in similar predicted differences in
longshore sediment transport rates at Bacton compared to Mundesley, but with slightly
different magnitudes (Figure 4.2).
It is noted that, within the model, the defences at Bacton refer to the timber breastwork
and groynes and that even under Scenario 2, no direct defences is included at the toe of
the cliff and it has to be assumed that some cliff recession has been allowed for along
the frontage under either of the scenarios. As more sediment becomes available from
the north under Scenario 1, this will further modify this behaviour of the Bacton frontage.
The plot shown in Figure 4.2, therefore, reflects several different processes happening
in combination. Quite clearly, there is the dominant feature of sediment moving through
the frontage from the north. However, with reference to Figure 4.1, the initial rise in the
difference plot is shown as occurring at the southern end of Mundesley (sections 48 and
49) between 2024 and 2025. From Figure 4.2, the initial increase in sediment difference
at Bacton (sections 44 and 45) is indicated to occur between 2023 and 2024 (section 43
in 2024 to 2025).
This might suggest that failure of defences at the northern end of Bacton releases
potentially some 20,000m3 to 30,000m3 additional sediment into the system in those
initial years. This is rapidly obscured by the strong additional drift supply from the north.
In general, therefore, the model shows that, between the mid-2020s and mid 2060s
(when failure of the revetment had taken place in Management Scenario 1) the
predicted difference in sediment transport rate for Management Scenario 1 is about
126,000m3/year (average) compared to Management Scenario 2 (Figure 4.2 and Table
4.3). Taking this as an average value and allowing for the variation throughout the
analysis this would suggest that the increased supply from the north dominates the drift
system over this period of time, potentially also causing in some reorientation of the plan
shape of the beach, further modifying drift behaviours..
Over the longer term as both scenarios settle in to a steadier state, the model suggests
that the drift rate across the Bacton frontage is higher than that across the undefended
Mundesley frontage (Figure 2.1).
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200,000.00
150,000.00
100,000.00
50,000.00
43
44
45
2010
2030
2050
2070
2090
2110
(50,000.00)
(100,000.00)
(150,000.00)
Figure 4.2. Differences in predicted longshore sediment transport rates between Management Scenarios 1 and 2 for the period 2013 to 2120
at Bacton. Positive values indicate that rates predicted for Management Scenario 1 are higher than Management Scenario 2
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Table 4.3. Differences in predicted longshore sediment transport rates between
Management Scenarios 1 and 2 for the period 2025 and 2066 at Bacton. Positive
values indicate that rates predicted for Management Scenario 1 are higher than
Management Scenario 2
3
Difference (m /year)
Section 43 (S)
Section 44
Section 45 (N)
Minimum
29,000
29,000
21,000
Maximum
178,000
180,000
188,000
Average
125,000
128,000
124,000
These observations have also to recognise potential influence due to changes further
south, in terms of the potential reorientation of the coast south of Bacton. This is
discussed below.
Comparison of Management Scenarios 1 and 2 at Walcott
While there are clear similarities, the pattern (or timescales) of differences between
Management Scenario 1 and Management Scenario 2 are different at Walcott compared
to Bacton and Mundesley. This reflects that the timing of structure failure at Walcott
under Management Scenario 2 is assumed to be different to both Bacton and
Mundesley.
At Walcott, all the structures under Management Scenario 1 fail between 2017 and 2037
(Table 4.1). The groynes (Sections 35-37) fail first between 2017 and 2025, followed by
the seawall (Sections 36 and 37) between 2022 and 2037, followed by the revetment
(Section 35) between 2024 and 2032. This sequencing is similar to Mundesley and
Walcott.
Under Management Scenario 2, the structures fail earlier than at Mundesley and
Walcott. The earliest failure is assumed to be the groynes (2030-2038) followed by the
seawall (2035-2050) and the revetment (2037-2045). Therefore, based solely on the
impact on drift at Walcott, it would be anticipated that the two scenarios coincide earlier;
the Walcott frontage is returned to a natural state at an earlier point in time. However,
introducing the influence of Mundesley / Bacton on sediment patterns, superimposes a
different pattern across the Walcott frontage.
Figure 4.3 shows the time series of the difference in predicted longshore sediment
transport rate between Management Scenarios 1 and 2 at Walcott. The initial pattern is
similar to Mundesley and Bacton, with a large increase in difference occurring in the
mid-2020s due to Management Scenario 1 structure failure at this time. However,
because the failure of structures under Management Scenario 2 follows closely after the
failure under Management Scenario 1, the difference peaks (276,000m3/year at Section
45 in 2028) and then falls sharply after that (Figure 4.3). The predicted difference
between Management Scenario 1 and Management Scenario 2 is effectively zero by the
early 2040s and, with no other influences, would be expected to remain close to zero up
to 2120.
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However, from the early 2040s up to the mid-2060s, the predicted difference in
longshore sediment transport rates between Management Scenario 1 and Management
Scenario 2 gradually increases to a peak of 141,000m3/year in the mid-2060s.
The potential explanation for this increase in sediment transport difference is input of
sediment to the Walcott frontage from sources further north (released under
Management Scenario 1 between the mid-2020s and mid-2060s at Mundesley and
Bacton). In the mid-2060s, the difference declines to almost zero, because the failure of
structures under Management Scenario 2 at Mundesley and Bacton starts to restore the
imbalance in the system on the Walcott frontage.
If a very basic assumption is made that the sediment from the north starts to affect the
Walcott frontage in the mid-2040s (as the difference between Management Scenarios 1
and 2 starts to climb, Figure 4.3), then it has travelled about 4km in 20 years (failure of
structures under Management Scenario 1 at Mundesley and Bacton is the mid-2020s).
This equates to a transport ‘speed’ of about 200m/year. This, however, is not consistent
with the effect seen at Bacton in relation to the change in drift as a result of the different
scenarios at Mundesley.
Considering the broader shape of the difference profiles (Figure 4.2 and 4.3) it is
possible to superimpose two alternative assumptions (Figure 4.4).
Figure 4.4. Superimposed Mundesley / Bacton profile
In the first (the red superimposed line), it is taken that the peak of the Mundesley /
Bacton profile coincides with the slight peak of the falling curve from Walcott. In the
second (the blue line), the profile is aligned with the second peak in the Walcott profile.
These give time difference of approximately 5 years (800m/year) and 2 years
(2km/year).
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300,000.00
250,000.00
200,000.00
150,000.00
35
100,000.00
36
37
50,000.00
2010
2030
2050
2070
2090
2110
(50,000.00)
(100,000.00)
Figure 4.3. Differences in predicted longshore sediment transport rates between Management Scenarios 1 and 2 for the period 2013 to 2120
at Walcott. Positive values indicate that rates predicted for Management Scenario 1 are higher than Management Scenario 2
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Implications for Sandscaping at Bacton
The comparisons show that if a ‘Hold the Line’ strategy is adopted at Mundesley
(Management Scenario 2), then smaller volumes of sediment would be transported
south than if a do nothing policy (Management Scenario 1) is adopted and the structures
fail within the next 10 years. An additional 65,000-130,000m3/year (overall average
97,000m3/year) of sediment would be transported along the Mundesley frontage if failure
is allowed to take place early. This volume increases from north to south along the
frontage.
The analysis is complicated at Bacton, in that the direct impact of holding the line at
Bacton is to a degree obscured by the sediment difference at Mundesley, feeding
through to the direct results at Bacton.
Taking both sections together it can be concluded that around 130,000m3/year would be
required to be fed into the system at Bacton to address the overall deficit in sediment
caused by the SMP hold the line policy.
The estimated transport ‘speeds’ range between 200m/year and 2km/year across this
study frontage.. The lower end of the range appears low considering the relatively rapid
movement between Mundesley and Bacton. A more realistic rate in the order of
1km/year would mean that sediment from a sand engine would take approximately 10
years to reach Cart Gap and 12 years to reach Sea Palling.
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Appendix D
Beach Profiles
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6
N069 - All Profiles, Upper Beach, Mundesley (Holiday Village)
13/07/1992
5
03/09/1999
19/01/2000
4
05/07/2000
HAT = 2.99mOD
24/07/2002
3
15/02/2006
12/02/2014
2
1
0
20
40
60
80
100
120
140
160
180
-1
-2
LAT = -2.53mOD
-3
-4
N069 - Profile Options, Upper Beach, Mundesley (Holiday Village)
24/07/2002
19/01/2004
12/02/2014
+4m 100m Crest 1:30
+4m 200m Crest 1:30
+5m 100m Crest 1:30
+5m 200m Crest 1:30
+6m 100m Crest 1:30
+6m 200m Crest 1:30
+7m 100m Crest 1:30
+7m 200m Crest 1:30
8
6
4
HAT = 2.99mOD
2
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
6
N070 - All Profiles, Upper Beach, Paston
13/08/1991
5
05/07/2000
22/01/2001
4
10/08/2007
11/08/2010
HAT = 2.99mOD
3
27/02/2013
12/02/2014
2
1
0
20
40
60
80
100
120
140
160
180
-1
-2
LAT = -2.53mOD
-3
-4
03/09/1999
24/07/2002
12/02/2014
+4m 100m Crest 1:30
+4m 200m Crest 1:30
+5m 100m Crest 1:30
+5m 200m Crest 1:30
+6m 100m Crest 1:30
+6m 200m Crest 1:30
+7m 100m Crest 1:30
+7m 100m Crest 1:30
N070 - Profile Options, Upper Beach, Paston
8
6
4
HAT = 2.99mOD
2
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
6
13/08/1991
N071 - All Profiles, Upper Beach, Bacton Gas Terminal
02/09/1999
5
17/03/2002
16/01/2003
4
24/01/2005
02/08/2005
11/08/2010
3
HAT = 2.99mOD
12/02/2014
2
1
0
20
40
60
80
100
120
140
160
180
-1
-2
LAT = -2.53mOD
-3
-4
N071 - Profile Options, Upper Beach, Bacton Gas Terminal
01/03/2011
23/07/2002
8
12/02/2014
+4m 100m Crest 1:30
6
+4m 200m Crest 1:30
+5m 100m Crest 1:30
4
+5m 200m Crest 1:30
+6m 100m Crest 1:30
HAT = 2.99mOD
+6m 200m Crest 1:30
2
+7m 100m Crest 1:30
+7m 200m Crest 1:30
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
6
N072 - All Profiles, Upper , Beach, Bacton (Caravan Park)
13/01/1995
31/08/1996
5
15/08/1997
23/08/2001
4
23/07/2002
25/07/2006
3
HAT = 2.99mOD
25/02/2008
12/02/2014
2
1
0
0
20
40
60
80
100
120
140
160
-1
-2
LAT = -2.53mOD
-3
-4
N072 - Profile Options, Upper Beach, Bacton (Caravan Park)
23/07/2002
31/01/2007
12/02/2014
+4m 100m Crest 1:30
+4m 200m Crest 1:30
+5m 100m Crest 1:30
+5m 200m Crest 1:30
+6m 100m Crest 1:30
+6m 200m Crest 1:30
+7m 100m Crest 1:30
+7m 200m Crest 1:30
8
6
4
HAT = 2.99mOD
2
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
6
N073 - All Profiles, Upper Beach, Bacton (Sea View Estate)
14/01/1992
5
01/08/1996
01/01/1997
4
18/01/2000
23/07/2002
HAT = 2.99mOD
3
21/01/2008
28/07/2011
2
12/02/2014
1
0
0
20
40
60
80
100
120
140
160
-1
-2
LAT = -2.53mOD
-3
-4
N073 - Profile Options, Upper Beach, Bacton (Sea View Estate)
8
6
4
HAT = 2.99mOD
2
23/07/2002
28/07/2011
12/02/2014
+4m 100m Crest 1:30
+4m 200m Crest 1:30
+5m 100m Crest 1:30
+5m 200m Crest 1:30
+6m 100m Crest 1:30
+6m 200m Crest 1:30
+7m 100m Crest 1:30
+7m 200m Crest 1;£0
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
6
N074 - All Profiles, Upper Beach, Walcott (Coast Rd)
12/08/1991
5
01/08/1996
4
05/07/2000
10/08/2010
3
HAT = 2.99mOD
27/02/2013
2
12/02/2014
1
0
0
20
40
60
80
100
120
140
160
-1
-2
LAT = -2.53mOD
-3
-4
N074 - Profile Options, Upper Beach, Walcott (Coast Road)
23/07/2002
28/07/2011
12/02/2014
+4m 100m Crest 1:30
+4m 200m Crest 1:30
+5m 100m Crest 1:30
+5m 200m Crest 1:30
+6m 100m Crest 1:30
+6m 200m Crest 1:30
+7m 100m Crest 1:30
+7m 200m Crest 1:30
8
6
4
HAT = 2.99mOD
2
0
0
100
200
300
400
500
600
700
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
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800
Variation in Beach Volume (HAT to LAT), Profiles N069 - N074
N069
N070
600
N071
N072
N073
Beach Volume above LAT (m3/m)
500
N074
400
300
200
100
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
Date
Bathymetry to 2km Offshore
N069 - 2002
N070 - 2002
6
N071 - 2002
4
HAT = 2.99mOD
N072 - 2002
N073 - 2002
2
N074 - 2002
0
0
200
400
600
800
1000
1200
1400
1600
1800
-2
LAT = -2.53mOD
-4
-6
-8
-10
-12
-14
-16
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2000
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Appendix E
Natural Environment Constraints & Opportunities
NORTH NORFOLK FEASIBILITY SANDSCAPING STUDY
ENVIRONMENTAL CONSIDERATIONS
Introduction
The feasibility study will address two issues, firstly the objectives of North Norfolk District Council
(NNDC) to protect the coast, especially in relation to the Bacton oil and gas terminal, and
secondly the potential opportunities which sandscaping could offer not only in terms of coastal
management but for other potential opportunities as well.
NNDC have been developing strategies for coastal management along this area of coast and
there is an immediate requirement to consider defence strategies particularly since the storm
surges of 2013 and 2014.
The approach for this study is to consider the criteria that a sandscaping project would need to
meet rather than providing a detailed design. This part of the study identifies the environmental
constraints and opportunities that a sandscaping approach to coastal management would need
to consider.
The study area considered for this part of the study is between Sheringham and Happisburgh on
the North Norfolk coast.
Environmental Designations
Shoreline Management Plans
Shoreline Management Plans have been developed in order to develop sustainable coastal
defence schemes and are based on identified sediment transport sub-cells (littoral cells) which
are independent lengths of coastline where there is movement from a ‘source’ to a ‘sink’. The
coastal area of North Norfolk is part of the designated cell 3 (the East Anglian coastline) and falls
within sub-cells 3A and 3B. The main source of sediment in this area are the cliffs where larger
material is deposited on the beaches and finer particles are deposited throughout the North Sea.
In this area cliff material is soft and vulnerable to wave erosion, the sand and gravel component
are permeable and clays impermeable a combination which has led to landslides.
Hard defences may influence sediment movement patterns and along this particular coastal area
the southern regions are dependent on sediment drift from the north provided in significant
quantities by eroding cliffs (to the north of Bacton). Between Kelling Hard and Happisburgh a
number of hard defences have already being established including groynes, rock armour, block
revetments, gabions and other methods. The general rate of erosion along this coastline is
variable with the lowest rates at Sherringham, Cromer and Bacton which may be as a result of
the defence structures currently in place. The Bacton oil terminal is heavily defended and the
policy for this area is to ‘hold the line’. Figure E1 shows the policy unit locations between
Sheringham and Happisburgh (the study area).
In this area hard defences are also protecting cliff top grassland ecosystems and the removal of
which could result in the loss of such habitats although new ones might also be established. Sea
defences in some of the sections of coast are thought to prevent the natural erosion of SSSI’s
designated for their geological exposure although they are also protecting settlements such as
the village of Walcott as well as a number of areas from erosion and salt intrusion into the Norfolk
Broads.
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Figure E1 SMP Policy Units
Defences which are preventing natural cliff erosion and sediment supply could result in loss of
beach habitats and beaches which in turn could create vulnerability for settlements in terms of
flooding. The area between Eccles and Winterton is especially vulnerable. Hard defence
structures are also protecting water bodies which are currently at good or moderate under the
WFD as well as preventing erosion of landfill sites near the coast. The opportunities and
constraints for sea defences are summarised in Table E5.
Habitats Regulation Assessment (HRA)
The Conservation of Species and Habitats Regulations 2010 (the Habitats Regulations)
implement EC Directive 92/43/EEC on the conservation of natural habitats and of wild flora and
fauna (the Habitats Directive). In accordance with Section 61 of the Habitats Regulations,
Appropriate Assessment (AA) is required for any plan or project, not connected with the
management of a European site, which is likely to have a significant effect on the site either
alone or in combination with other plans and projects.
European sites comprise Special Protection Areas (SPAs), as designated under Council
Directive 79/409/EEC (the Wild Birds Directive), or Special Areas of Conservation (SACs), as
designated under the Habitats Directive. An AA is also required as a matter of government
policy for potential SPAs, candidate SACs and listed Ramsar sites for the purpose of considering
development proposals affecting them (ODPM, 2005). There are a number of protected sites and
species along this coastal area and include Special Areas of Conservation (SAC’s), Special
protected Area (SPA’s), Sites of Special Scientific Interest (SSSI’s) and Ramsar sites, as shown
in Figure E2.
Wildlife and Countryside Act 1981 (as amended)
Under the terms of Section 28(4)b of the Wildlife and Countryside Act 1981 as amended by
Schedule 9 to the Countryside and Rights Of Way Act 2000, any operations within, or adjacent
to, a Site of Special Scientific Interest (SSSI) require consent from Natural England.
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Figure E2 Protected Sites in the Study Area
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Designated Sites within the study area
Sidestrand Trimmingham Cliffs SSSI
Sidestrand-Trimingham Cliffs to the north of Mundesley has six notified interest features, the first
four are geological, and the last two in the list are biological:
•
Cenomanian-Maastrichtian;
•
Pleistocene Vertebrata;
•
Quaternary Of East Anglia;
•
Mass Movement;
•
Invertebrate Assemblage; and
•
Population of RDB plant - Purple Broomrape Orobanche purpurea,
Overstrand cliffs SSSI and SAC
Overstrand Cliffs are located to the south of Cromer and are considered to be one of the best
examples of unprotected vegetated soft cliffs on the coast of the North Sea. Composed mainly
of sand and clays they are subject to freshwater seepage and as a result frequent landslides.
There are no sea defences to protect the cliffs from natural erosion and there is a natural
succession of communities on the exposed sands and mud. The range of habitats is diverse and
supports a diverse assemblage of invertebrates.
Overstrand Cliffs has three SSSI interest features:
•
Quaternary Of East Anglia;
•
Invertebrate Assemblage; and
•
MC9 - Maritime grassland Festuca rubra, Holcus lanatus.
The SAC feature is:
•
1230 Vegetated sea cliffs of the Atlantic and Baltic coasts
Happisburgh, Hammond and Winterton - Offshore Special Area of Conservation (SAC)
This site is approximately 12miles offshore to the west of Happisburgh and Winterton. The
primary reason for the selection of this site as an SAC are the following Annex 1 habitats:
•
Sandbanks which are slightly covered by sea water all of the time;
•
Reefs – these include Sabellaria spinulosa reefs at Happisburgh Tail, Happisburgh
Gat and between Winterton Ridge and Hewett Ridge; and
•
The Wash and North Norfolk Coast Inshore SAC with Marine Components SAC.
North Norfolk Coast SPA
This area encompasses most of the northern coastline of Norfolk and extends 40km between
Holme to Weybourne and includes extensive intertidal sand and mudflats, saltmarshes, shingle
and sand dunes. Due to the diversity and quality of the freshwater, intertidal and marine sites
there are a large number of species of water bird found throughout the year. Breeding population
of waders, bitterns Botaurus stellaris, wetland raptors such as the March Harrier Circus
aeruginosus and four species of tern are present on the coastal dune areas in summer. In the
winter species of geese, sea-ducks and waders are present. During the spring and autumn
migration period for waterbirds this site is an important staging place. The little tern breeds at
nine main sites in Norfolk, in the north and east of the county and these sites support one-third of
the UK population. The best nesting sites consist of suitable areas of mixed shingle and sand,
with plenty of marram grass or other vegetation nearby where the chicks can hide.
Winterton – Horsey Dunes SSSI, SAC and SPA
This dune system is located to the south of the study area and is considered to be the only
significant area of dune heath on the east coast of England (JNCC 2014) including acidic dune
grassland and associated acidic habitat. The feature for this SPA are breeding terns.
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Ramsar sites
The Wash, and the North Norfolk Coast 40km between Hunstanton and Weybourne (45km NW
of Norwich)
North Norfolk SSSI
This area extends from Holme-next-the-Sea to Kelling and is protected through Natura 2000,
SPA listings and part of the Norfolk Coast AONB. Much of the area is a biosphere reserve.
Marine Conservation Zones (MCZ)
Cromer Shoals Chalk Beds – recommended MCZ (rMCZ)
The coastal area 200m offshore from the study area adjacent to Sheringham, Cromer, West
Weybourne and Sea Palling is a rMCZ. The water depth ranges from 0-20m with a seabed
comprising rock, sediment, blue mussel beds and peat and clay exposures. Within the site are
some of the best examples of subtidal chalk in the North Sea and forms the longest chalk reef in
Europe with chalk arches 550m from the shore. The site is recommended as an MCZ due to the
presence of three broadscale habitats (High and moderate energy infralittoral rock and moderate
energy circalittoral rock), a habitat of conservation importance (subtidal chalk), and a geological
feature (North Norfolk coast (subtidal). The chalk habitat supports a large population of sponges,
crustacea, squirts and cnidarians as well as bryozoans, dragonets, squat lobster Munidopsis
serricornis, algae, lesser sandeel Ammodytes tobianus and piddock Barnea truncata. The
western edge of the site abuts to the Wash and North Norfolk Coast SAC within which are areas
of marine eelgrass (Zostera spp.) which are important nursery grounds for Dover sole Solea
solea, lemon sole Microstomus kitt, whiting Merlangius merlangus and sandeel. This area is also
an important fishing ground.
The recommendations will be submitted for public consultation in January 2015 and the decision
on designation will be decided upon. Once the rMCZ reaches Proposed status the site will
become protected.
Water Framework Directive
The Water Framework Directive (WFD) applies to all water bodies including those which are
man-made. The Directive was transposed into national law in 2003 by means of the Water
Environment (Water Framework Directive) (England and Wales) Regulations, 2003. These
Regulations provided for the implementation of the WFD in England and Wales, with an aim to
achieve ‘good ecological status’ by 2015.
The lead competent authority for the WFD in England is the Environment Agency and is
responsible for producing River Basin Management Plans (RBMPs). Within their regulatory
remits the Marine Management Organisation and North Norfolk County Council, as public bodies,
must have regard to the WFD and any RBMP when considering applications made for consent
for activities.
Within the area relating to this feasibility study Norfolk East has been identified as a WFD
waterbody with an ecological status of ‘Moderate Potential’ but at overall risk due to nitrate influx
from surrounding agricultural land. This classification indicates that although the water quality is
of sufficient quality to support a healthy ecosystem there may be a limitation to the ‘Ecological
Potential’ as a result of high nitrogen concentration from the use of nitrates. This WFD coastal
water body covers the whole coastal zone within the study area and is associated with a Natura
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2000 site. Since there is an overall risk associated with this coastal water body there are three
mitigation measures identified and in place and these include;
•
Managed disturbance;
•
Site selection – the disposal of any dredged materials is subject to site selection
criteria; and
•
Sediment management.
The potential constraints and opportunities of sandscaping on such waterbodies is considered in
Table E5 below.
Commercial Fisheries
Background
The fishing industry in North Norfolk has a long history of being a family based traditional activity
with daily landings of shellfish from small under 10m beach boats. More recently larger boats
have joined the fleet and fish further offshore in deeper waters and tend to stay out for longer
periods of time. In the mid 1980’s whelk fishing declined and with this came an increased effort
for catching other species of shellfish. More recently the whelk fishery is beginning to show initial
signs of recovery as shown in landings data.
Species of commercial importance for the inshore fisheries of the North Norfolk coast are mainly
shellfish species, namely edible crab Cancer pagurus, velvet swimming crab Necora puber,
European lobster Homarus gammarus and further offshore the whelk Buccinum undatum. Crab
and lobster fishing is seasonal and the majority of landings are between spring and autumn with
a peak during May and June.
The gear used can be traditional or parlour pots from either beach-boats (under 10m) which fish
close to the shoreline (5miles) or larger boats (mainly catamarans) which tend to stay out for
longer periods of time (10 hours or more) to set pots further offshore. Currently there are around
20 offshore crab and lobster boats which fish up to 50 miles from the main harbours of Morsten,
Wells-next-the Sea and Brancaster often setting up to 1000 pots whereas the smaller boats can
set up to 250 pots in lines of 25. Soaking time for offshore pots is generally over a tidal cycle and
the larger boats tend to use parlour pots almost exclusively because of their larger size and
greater catch retention. In the inshore fleet there are approximately 44 boats which work off the
open beaches of Cley, Salthouse, Weybourne, Sheringham, The Runtons, Cromer, Overstrand,
Mundesley, Bacton and Sea Palling. Table E1 shows the distribution of boats targeting shellfish
along the North Norfolk coast in 2011.
Table E1 Distribution of shellfish boats on North Norfolk Coast 2011 (After FLAG 2011)
Port
Number of boats
Brancaster
5
Wells
10
Blakeney
6
Sheringham
6
East Runton
6
Cromer
8
Overstrand
3
Total
44
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With increasing technology on board the larger boats have a small crew of 2-3 whereas the
inshore fleet have reduced from 2-3 crew to a single operator on many of the faster skiffs (FLAG
2011). There is also a fishery for mussels to the north of the study area (Brancaster) as well as
bottom dwelling flatfish namely flounder Platichthys flesus, dab Limanda limanda and sole.
Table E2 and Table E3 show the quantity and value of key species caught in the main ports in
the study area namely Sheringham and Cromer. These figures show that shellfish are the most
important by value and weight in the area but the catch is seasonal with a peak in early summer.
The industry in Sheringham and Cromer relies mainly on brown crab and lobster caught between
March and October and bass and other species during the winter months. There are good crab
and lobster grounds along the chalk reefs between Cley and Bacton and with factories at Cromer
and Sheringham there is a considerable amount of processing of catch for export to Europe.
Further north around Brancaster oysters, clams and mussels are cultivated under several orders
and there is also an important fishery for brown crab. Whelk catch is beginning to increase since
the decline in the 1980’s although this is still in its infancy.
In 2011 a SWOT analysis carried out by the Fisheries Local Action Group (FLAG) indicated that
although the fishery had a strong identity and market which has been improved by tourism the
threat of disruption by offshore wind farms, lack of infrastructure, higher input prices and coastal
erosion, amongst other threats, has put the sustainability of the industry at risk (FLAG 2011).
Table E2 Catch by port and month (fish and shellfish), landed weight (tonnes) and value
(£) (MMO 2014) - Sheringham
Species
Method
Landed weight
Jan
Feb
Mar
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
(tonnes),
Value (£)
Crab
Pots
Lobster
Bass
Nets
Wt
0.65
3.59
1.84
1.70
1.30
1.49
0.45
0.24
Value
950
5411
2989
2595
2045
2123
850
425
Wt
0.17
0.34
0.004
0.16
0.11
0.03
0.02
0.01
Value
2207
4190
36
1721
1027
299
186
44
Wt
0.35
Value
1091
Spatial distribution of fish and shellfish species
In 2010 the Eastern Inshore Fisheries Conservation Authority interviewed a number of fishermen
in order to define the areas in which they fished for a variety of species. The fishing maps which
were produced provide a snapshot of the spatial distribution of the main commercial species and
are shown in Figure E3. It should be noted that Figure E3 provides an indication only of the
importance of the area for the inshore fleet, the key species targeted and the spatial extent of
fishing activities.
The key species which need to be considered include those which could be affected by an
increase in sediment deposition and suspended sediment concentration and sediment removal.
These are primarily shellfish species especially those with limited ability to move away from
adverse environments and which may be susceptible to smothering.
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Table E3 Catch by port and month (fish and shellfish), landed weight (tonnes) and value (£) (MMO 2014) - Cromer
Species
Method
Landed weight
Jan
Feb
March
Apr
May
Jun
July
Aug
Sep
Oct
Nov
Dec
0.07
0.07
0.03
2.66
11.20
13.10
7.57
5.73
4.59
1.83
1.70
0.25
(tonnes)
Value (£)
Crab
Pots
Wt
Value
91
77
32
4245
18832
21602
12717
8937
6131
2183
2116
303
Lobster
Pots
Wt
0.097
0.31
0.09
1.10
2.40
1.40
3.34
4.04
1.97
1.42
0.45
0.02
Value
1075
5006
1458
14975
29492
13502
30057
32333
17189
13558
4487
216
Whelk
Pots/ traps
Wt
10.40
6.25
4.99
4.73
1.55
2.15
2.06
1.02
6.08
5.66
Value
6550
3943
3139
2978
971
1354
1300
638
4210
3960
Bass
Hooks/fixed
Wt
0.05
0.13
0.05
0.04
0.19
0.04
0.007
net/pots and
Value
347
954
383
250
1084
275
43.40
Wt
0.004
0.002
0.004
0.002
0.001
Value
31.70
5
10
6
4
0.0008
0.0006
traps
Sole
Pots/traps
Flounder
Drift/fixed
or fluke
nets,
Dab
Wt
pots/traps
Value
Drift/fixed
Wt
0.003
0.02
0.02
0.001
0.05
nets,
Value
20
139
132
0.50
16.00
Wt
0.003
Value
15
Wt
0.006
0.005
Value
33.00
22.50
1.50
1.00
pots/traps
Cod
Pots/traps
Skates
Pots/ traps
0.02
45.50
and rays
Shrimp
Herring
Pots/traps
Wt
0.02
Value
66.00
Pots and
Wt
0.02
0.04
traps
Value
15.00
39.00
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Figure E3 Location of Fishing Grounds for Key Species of Fish and Shellfish
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The reproductive behaviour of the brown/edible crab involves periods of migration in
relation to spawning behaviour. Females move inshore in late spring to moult prior to
mating and in late summer berried individuals will move offshore to remain in shallow
pits or under rocks whilst the fertilised eggs incubate. Six to nine months later the larvae
are released into the water column where they remain in the plankton for approximately
two months before settling as juveniles in the intertidal area in summer early autumn.
After about three years the crab will move offshore to subtidal regions to feed. Migratory
routes for female crab can be extensive in comparison to males and tagging studies
carried out in Yorkshire and Norfolk identified a northward migratory route for adult
female crab from Norfolk to Yorkshire and Northumberland (Figure E4) (Bannister
2009). The wider study of migration in female crabs indicate that migration tends to be
upstream in order for larvae to return to the original place of birth. Therefore along the
coast of Norfolk there is expected to be a northward migration of adult females and a
southerly movement of larvae although currents around Flamborough Head to the north
tend to move offshore rather than directly south.
Figure E4 Female Crab Migration Routes3
The European lobster is also caught in the inshore areas and like brown crab females
are inactive during the period of egg incubation which could take up to nine months.
The brown and pink shrimp fishery on the east coast has already undergone a preassessment under the Marine Stewardship Council Principles and Criteria for
3
Crab migration data recreated from illustration. Buckland Lecture at the SAGB Conference, London.: “Science and the
Management of United Kingdom Crab Fisheries ” by Dr J T Addison, CEFAS Lowestoft (see http://www.shellfish.org.uk )
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Sustainable Fisheries and are considered to require a management strategy to ensure
not only the sustainability of the fishery but also in relation to the impact on sensitive
habitats.
The mussel Mytilus edulis is a filter feeder and forms large beds attached to rocky
outcrops in the intertidal zone and whelk Buccinum undatum is found predominantly on
soft substrates such as coarse sand and commonly in subtidal zones. On soft surfaces
whelk will burrow into the surface layers with only the siphon protruding for respiration.
Both species have limited movement and although mussel beds are mainly to the north
and south of the study area both species are susceptible to high concentrations of
suspended sediment in the water column and smothering as a result of deposited
material.
Species of fish in the area have been identified form catch figures Table E2 and Table
E3 although these are only species of commercial importance and may not identify all
species present. Most species of fish can move away from adverse environments
although sandeel species are particularly associated with sandy substrates due to the
habit of burrowing into the sand only emerging to feed and breed.
Consultation
Consultation has been undertaken with the Crown Estate and Natural England the
Sussex IFCA, Cefas, MMO, to identify the potential constraints and opportunities of the
proposal. Table E4 indicates the consultation undertaken to date.
Table E4 Consultees
Consultee
Organisation
Date
Helen Dixon
Natural England
6th October 2014
Jennifer Fincham
Natural England
9th October 2014
Jennifer Stout
Eastern Inland Fisheries Conservation Authority (IFCA)
15th October 2014
Colin Warwick
Crown Estate (Fisheries)
6th October 2014
MMO request for information
MMO
15th October 2014
Vicky Bendall
Cefas (by mail)
15th October 2014
Anita Franco
Institute of Estuarine and Coastal Studies (IECS)
15th October 2014
University of Hull
POTENTIAL CONSTRAINTS AND OPPORTUNITIES
Environmental Designations
The information collected on environmental designations and the consultation to date
has been considered in order to identify the constraints and opportunities which need to
be considered in any further studies for sandscaping. Table 5 provides a summary of
the main environmental constraints and opportunities.
Fisheries
The baseline study identified that the key fisheries operating in the area are either
inshore with beach boats or offshore using fast super 10 catarmarans (CATS). The
importance of the shellfisheries such as crab, lobster and the burgeoning whelk fishery
is shown by the value landed (Table E2 and Table E3).
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Table 5 Potential constraints and opportunities identified
Item
Management Policies
Sea defences
Rationale
Constraint /
Opportunity
The SMP/SEA identified that a reduction in sea defences along this area of coastline could result in positive impacts in terms of establishing of beaches natural
functioning of the coast and sediment supply to European protected sites. In particular as identified in the following sections Mundesley Cliffs in the immediate
vicinity of Bacton are designated as SSSI for natural exposure and within policy area 6.10 (SEA 2013). The policy for this unit is currently to hold the line which
could affect the natural processes for this area as well as Winterton and Horsey Dunes SAC. Although the policy aim is conditional on further monitoring and
there are measures within the policy for beach recharge which should be considered in relation to the sandscaping option.
Opportunity
Environmental Designations
Natural England would like the following information to be provided as part of any future studies in order to come to a view on impact to the SSSIs including: likely changes to erosion rates; likely beach levels;
likely cliff profiles; quantity of sediment, the likely future profile of the coastline and how current coastal processes will operate.
E.g. is the anticipation that there will be a massive beach such that waves will rarely reach the cliffs and thereby reduce or even stop erosion from waves for a period of time? Or is the plan to place the sand
slightly offshore such that wave breaking might occur which may limit the erosive power of waves but still allow waves to reach the beach and cliffs and allow some erosion to still occur?
Mundesley and
These cliffs are both designated SSSI of geological interest only. Both are designated for cliff exposure of the Cromer Forest bed and contain fossil layers of
Constraint and
Happisburgh Cliffs SSSI
interest. Till deposits are important features as well. The target for both of these sites is to maintain the natural coastal processes for exposure of the cliff. The
Opportunity
main exposure area to maintain is in the upper cliff at Mundesley.
Natural England considers that a build-up of sediment at the base of the cliff to slow the rate of exposure is acceptable but not to the extent that exposure is
prevented. The rate of sediment deposition needs to be within acceptable limits.
Winterton and Horsey
This dune system is designated SSSI and SAC. The interest feature here is the breeding tern colony. The designation is to protect breeding and feeding
Opportunity
Dunes SSSI and SAC
habitats within the dune system. There could be a benefit of the development of a foredune area as a result of sediment deposition since high tides and scour
SPA feature (little tern)
have removed some of the habitat in the recent past. However if there is a build-up of sediment in the future as a result of sandscaping Natural England would
not agree to this being removed at a future date for recharge or sandscaping purposes.
Overstrand Cliffs
Geological notified features at the SSSIs comprise the entire cliff profile therefore erosion and sedimentation rates should consider the whole cliff feature.
Constraint
SSSI/SAC, Sidestrand &
Trimmingham Cliffs SSSI
Happisburgh Hammond
Any removal or deposition of sediment in this area would need to avoid any impact to the features associated with this SAC namely the Sandbanks slightly
Constraint
Winterton Offshore SAC
covered with seawater at all times and the Sabellaria spinulosa reefs.
AONB Happisburgh to
Natural England considers that archaeology is an important consideration at Happisburgh. The foreshore here (the Cromer Forest Bed) has evidence of early
Constraint
Winterton
humans and this is thought to be the site with the oldest evidence of human occupation in Britain. There has been considerable interest in this site and the
advice is that English Heritage should be consulted regarding impacts to the archaeology.
Marine Conservation Zones
Cromer Chalk Beds rMCZ
This area may be protected as a designated MCZ in January 2015. Within the chalk reefs are a considerable number of biotopes and species which could be
Constraint
adversely affected by sediment deposition depending on the nature, depth and duration of the deposited material.
Water Framework Directive
WFD Coastal Water Body
There is a potential for deposition of sediment within the area designated as a coastal waterbody depending on where the sediment for sandscaping is placed.
Constraint
– Norfolk East
This could affect the mitigation measures already in place especially those relating to sediment management and site selection of dredge material for disposal.
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The following Table E6 identifies the potential constraints and opportunities will need to
be considered in relation to the commercial fisheries operations and fish and shellfish
species in the area.
Table E6 Constraints and opportunities for fishing and fish and shellfish ecology
Issue
Rationale
Constraint /
Beach landing
Most of the inshore boats are beach landed. If there was a change in beach
Constraint
Opportunity
morphology as a result of the rate and level of sediment deposition this would
adversely affect the ability to land boats. The offshore fleet of CATS are also
landed on beaches.
Gear loss
High levels of sediment deposition could smother gear such as pots.
Constraint
Disruption to
Many boats are also processing the catch on-board, beach boats and the larger
Constraint
fishery industry
CATS which also land on the beaches. Loss of beaches will cause substantial
disruption to the industry.
Effect on fishing
The rates and depths of deposition need to be considered especially if there is a
areas
potential for the inshore areas such as firmer ground to be affected by deposition or
Constraint
Water quality
Shellfish require good water quality and a food source. There needs to be a
removal of sediment.
Constraint
consideration of the effect on the food chain of changes to sediment patterns and
distribution. Heavy deposition may affect the distribution of shellfish and flatfish
through the alteration of habitats. High sediment concentrations could affect filter
feeding mechanisms and cause smothering in shellfish.
Safety
Potential changes in the seabed morphology and possibly the existing sand banks
Stakeholder
Lack of engagement with the fisheries industry early in the process will be
engagement
detrimental to support for the process. There is a lot of local knowledge about the
Constraint
may affect the safe waters.
Constraint
seabed, sand areas and sand movement
Fish and shellfish
A consideration of the spatial distribution of fish and shellfish species is needed in
ecology
relation to potential smothering and loss of habitat. Crab and lobster migration
Constraint
routes and female burrowing areas, benthic habitats for bottom dwelling species
may potentially be affected by high suspended sediment loading and changes in
habitat character as a result of removal or deposition of material.
Summary
This assessment has identified a variety of constraints and some opportunities which
should be considered as part of any further design studies for undertaking sandscaping
projects. The main concerns were in relation to changes to interest features for
designated sites as a result of changes in erosion rates, deposition or removal of
sediment. In relation to commercial fisheries the main areas of concern were associated
with the potential effects on fishing habitats and the distribution of fish and shellfish, the
loss of gear, loss of beach profile for beach landing and adverse effects on the general
ecology of bottom dwelling species.
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Appendix F
Costs Assessment