Jonathan Edwards
Wychavon District Council
Development Control
Civic Centre Queen
Elizabeth Drive
Pershore
Worcestershire
WR10 1PT
Our ref:
Your ref:
SV/2014/107867/01-L01
W/14/01244/PN
Date:
30 July 2014
Dear Sir/Madam,
PROPOSED GROUND MOUNTED SOLAR FARM, ASSOCIATED WORKS AND
ANCILLARY INFRASTRUCTURE
DEFFORD AERODROME, REBECCA ROAD, BESFORD, WORCESTER
Thank you for consulting us on this application which was received on 3 July 2014.
We are also grateful for an extension to the deadline for our response.
I can confirm that we currently object to the application due to concerns in relation to
flood risk. The proposed development also presents a contamination risk to
controlled waters but we believe that this can be satisfactorily addressed through the
inclusion of conditions on any planning permission granted. We make the following
comments in relation to flood risk and land contamination.
Flood Risk
The proposed solar panels in the south west corner of the site are shown on our
flood map to be located in Flood Zone 3 (high probability) which is defined at Table 1
within the Flood Risk section of the Planning Practice Guidance (PPG) to the
National Planning Policy Framework (NPPF) as land having a 1 in 100 or greater
annual probability of river flooding. This flood plain is considered to be primarily
associated with Bourne Brook; an ordinary watercourse that flows in a south/south
eastern direction through the site. A section of the brook running through the south
west of the site is in culvert. There is also a minor tributary to the Bourne Brook
running in a west/south-westerly direction through the southern part of the site. This
section of watercourse is also in culvert through part of the site and it is considered
that this may contribute to the identified flood risk.
The FRA
The Flood Risk Assessment (FRA) submitted with the application (Stage 2 Flood
Risk Assessment Ref. 5142/2.3F produced by GTA Civils June 2014) is not
considered adequate to support the proposed development. Firstly, the FRA
suggests at paragraph 3.2 that the development is entirely within Flood Zone 1 and
so is at low risk of flooding. It acknowledges that a small section of the site is
located in Flood Zone 3A, but infers that there are no solar panels or buildings in this
area. These statements within the FRA are not consistent with our flood map and,
as noted above, a number of the solar panels in the south west corner of the site are
shown to be located in Flood Zone 3.
Secondly, our flood map in relation to this site is based on a general mapping
technique (J flow) rather than a detailed hydraulic model and is not able to fully
assess the culverted length of ordinary watercourse through the site or the potential
for it to block. Further evidence is therefore required to ensure that the proposed
panels are located out of the floodplain so to avoid the development causing a
reduction in flood storage capacity and to protect the installation. The generalised
modelling used to produce our flood map may have only picked up the lower ground
levels adjacent to where the watercourse is culverted and does not necessarily
confirm that the other areas proposed for the panels and shown to be within Flood
Zone 1 are out of the floodplain.
To verify the potential flood corridor a more detailed topographical survey should be
undertaken for the area of the site considered to be at flood risk. An analysis should
also be undertaken to assess the capacity of the culvert to convey flood flows during
a range of return periods (i.e. 1 in 20, 1 in 100, 1 in 100 plus climate change) in order
to verify the flood map extent and to identify a flow route should the culvert block.
On the above basis, it is considered that an accurate understanding of the flood risks
associated with the development cannot be achieved from the available information,
including the EA flood map and the FRA submitted with the application. An updated
FRA is therefore required.
Policy matters
The NPPF advises that a Sequential Test should be applied to the location of
development to avoid where possible flood risk to people and property. Paragraph
101 of the NPPF advises that “The aim of the Sequential Test is to steer new
development to areas with the lowest probability of flooding. Development should not
be allocated or permitted where there are reasonably available sites appropriate for
the proposed development in areas with a lower probability of flooding.”
In accordance with the requirements of the Sequential Test, the aim should be to
avoid flood risks to the development by locating it in the parts of the site within Flood
Zone 1. It is ultimately for the LPA to consider the extent to which Sequential Test
considerations have been satisfied, but we would comment that based on the
available information part of the development is shown to be located in Flood Zone 3
and it is noted that no information is provided with the application to demonstrate that
other lower flood risk parts of the site have been first considered.
An updated FRA providing a more accurate understanding of the flood risk to the site
(as detailed above) should help to inform the site layout with the aim of locating all
development in Flood Zone 1.
Furthermore, the Council should be mindful of the requirements of the Exception
Test as described at Paragraph 102 of the NPPF. Based on the available
information part of the development is shown to be located in Flood Zone 3. Table 3
within the Flood Risk section of the PPG indicates that for ‘essential infrastructure’
(includes renewable energy installations) within Flood Zone 3 the Exception Test is
required. Paragraph 102 of the NPPF states that “For the Exception Test to be
passed:

it must be demonstrated that the development provides wider sustainability
benefits to the community that outweigh flood risk, informed by a Strategic
Flood Risk Assessment where one has been prepared; and

a site-specific flood risk assessment must demonstrate that the development
will be safe for its lifetime taking account of the vulnerability of its users,
without increasing flood risk elsewhere, and, where possible, will reduce flood
risk overall.
Both elements of the test will have to be passed for development to be allocated or
permitted.”
Thus, if following a more accurate assessment of flood risk (via an updated FRA)
some of the proposed panels remain in Flood Zone 3, and the Council is satisfied
that the application passes the Sequential Test, the proposal must pass the
Exception Test as set out above.
The first requirement of the Exception Test relates to a wider planning consideration
for the Council’s consideration. The second requirement would require assessment
in a revised FRA, which should demonstrate that the solar panels will remain
operational and safe in times of flood, result in no net loss of floodplain storage and
not impede water flows and not increase flood risk elsewhere.
Other flood risk matters
It is EA policy to seek to establish the re-opening of culverted watercourses where
possible as this provides flood risk and biodiversity benefits. If, as indicated, the
applicant is not minded to re-establish an open channel reasons should be provided
as to why this is the case. Any alterations to the Ordinary Watercourse may require
the consent of the Lead Local Flood Authority (LLFA).
The applicant has indicated that they do not intend to provide any formal drainage.
The LLFA should be consulted to determine if this is considered acceptable in this
location.
Land Contamination
The site is a large site at 104 hectares and is underlain by three types of Jurassic
bedrock geology: the Charmouth Mudstone Formation (mudstone) in the east; the
Rugby Limestone Member (mudstone and limestone interbedded) in the west and
central area; and the Saltford Shale Member (mudstone) in the far west, the latter
two types being part of the Blue Lias Formation. Strata have a generally shallow dip
to the east. There is only one small isolated area of superficial deposits comprising
the Wasperton Sand and Gravel Member, located in the north-west corner. The
Charmouth Mudstone is classified as ‘Unproductive Strata’, the Saltford Shale as a
‘Secondary B’ aquifer, and the Rugby Limestone and Wasperton Gravel as
‘Secondary A’ aquifers. Secondary aquifers may support local supplies of
groundwater abstraction as well as providing baseflow to watercourses. There is an
east-west trending fault (downthrow to the south) present in the southern area, which
butts up to a north-north-east to south-south-west trending fault (downthrow to the
east) across the east and central area. Soils are described as slowly permeable,
calcareous, clayey soils.
The Bourne Brook flows through the south-west portion of the site, partly in culvert,
and is joined by tributaries from the north-east and south-west. A salt spring and
salt bath covert is located immediately to the west of the far south-west portion of the
site. The memoir for Worcester suggests that the halite deposits may be present at
depth to the east of the Smite-Pirton-Tewkesbury fault system. The spring may be
associated with the presence of a fault which is mapped close by.
There are no licenced abstractions located within the site. There is one deregulated
abstraction from a well 350m to the west at Dunstall Farm, and one approximately
900m to the south-east at Croft Farm, both for general farming and domestic
use. There are a number of licenced surface water abstractions approximately 11.5km to the east and south. However, there may be other private supplies that we
are not aware of – the local council should be contacted to provide this information
for use in a risk assessment.
The site has been used as a wartime airfield from 1941 and post-war until 1957 for
radar development, which could have resulted in contamination being present in the
soils and groundwater underlying the site. Several strips of land in and around the
site have been used as a landfill historically between 1987 to 1990, and from 1994 to
1996, recorded as depositing clean soil where we have information. However, the
Agricultural Appraisal noted the ‘easterly parcel and other land close to the perimeter
taxiway is severely contaminated with imported soil of varying composition, rubble
and waste products such as plastic’.
The former use of the site and construction of the solar farm has the potential to
impact on groundwater quality due to historic contamination, ground disturbance and
fuel/chemical storage during construction, and use of contaminating substances
during operation such as transformer oil and oil/fuel from vehicle parking. Loss of
concrete may occur during pouring if the underlying bedrock is fissured limestone.
Alarm systems should be installed to detect failure of equipment and should be
connected to control rooms via telemetry. In the event of equipment failure,
discharge of oils to ground must be prevented by adequate pollution prevention
measures, including an emergency plan for implementation in such an event.
In light of the above, we recommend that the following conditions are included on
any planning permission to secure the assessment of land contamination matters.
The contamination assessment should include details of all water features in and
around the site that are potentially at risk of contamination, and a foundation works
risk assessment should be provided. Foul drainage arrangements also need to be
considered and details provided.
CONDITION
No development approved by this planning permission (or such other date or stage
in development as may be agreed in writing with the Local Planning Authority), shall
take place until a scheme that includes the following components to deal with the
risks associated with contamination of the site shall each be submitted to and
approved, in writing, by the local planning authority:
1) A preliminary risk assessment which has identified:
 all previous uses
 potential contaminants associated with those uses
 a conceptual model of the site indicating sources, pathways and receptors
 potentially unacceptable risks arising from contamination at the site.
2) A site investigation scheme, based on (1) to provide information for a detailed
assessment of the risk to all receptors that may be affected, including those off site.
3) The results of the site investigation and detailed risk assessment referred to in (2)
and, based on these, an options appraisal and remediation strategy giving full details
of the remediation measures required and how they are to be undertaken.
4) A verification plan providing details of the data that will be collected in order to
demonstrate that the works set out in the remediation strategy in (3) are complete
and identifying any requirements for longer-term monitoring of pollutant linkages,
maintenance and arrangements for contingency action.
Any changes to these components require the express written consent of the local
planning authority. The scheme shall be implemented as approved.
REASON
To ensure the protection of controlled waters
CONDITION
If, during development, contamination not previously identified is found to be present
at the site then no further development (unless otherwise agreed in writing with the
local planning authority) shall be carried out until the developer has submitted a
remediation strategy to the local planning authority detailing how this unsuspected
contamination shall be dealt with and obtained written approval from the local
planning authority. The remediation strategy shall be implemented as approved.
REASON
To ensure the protection of controlled waters
CONDITION
Piling or any other foundation designs using penetrative methods shall not be
permitted other than with the express written consent of the local planning authority,
which may be given for those parts of the site where it has been demonstrated that
there is no resultant unacceptable risk to groundwater. The development shall be
carried out in accordance with the approved details.
REASON
To ensure the protection of controlled waters
Please note that without these conditions, the proposed development on this site
poses an unacceptable risk to the environment and we would object to the
application.
Conclusion
Based on the information provided with the application we are unable to make
accurate conclusions in relation to the flood risks associated with the development.
An updated FRA should be submitted providing a more accurate understanding of
the flood risks associated with the development taking into account the effect of the
culvert and the topography of the site. The requirements of the Sequential Test and
Exception Test should also be addressed insofar as they are relevant following the
production of a more accurate assessment of flood risk.
I trust this letter is clear but please do not hesitate to contact me if you would liek to
discuss this letter in more detail.
Yours faithfully
Mr Matthew Tyas MSc MRTPI
Senior Planning Advisor
Direct dial 01684 864381
Direct e-mail matt.tyas@environment-agency.gov.uk