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Environment Agency's Response

 Thanet District Council
 Development Services
 PO Box 9
 CT9 1XZ

Our ref:      KT/2008/105542/01-L01
Your ref:      TH/08/0400

Date:           02 May 2008

Dear  Sir/Madam,




 Thank you for your letter dated 10th April. The Environment Agency has no objection in principle to this proposal, and would like to request the following conditions and offer the following advice.

 Groundwater and Contaminated Land
The Environment Agency has the following comments regarding the redevelopment of land at the above location.
The site lies on the upper chalk formation; this is classified as a major aquifer. The site lies in Source Protection Zones (SPZ) 1, 2 and 3 for the Sparrows Castle public water supply. This site therefore lies in a vulnerable location in terms of groundwater protection and all precautions should be taken to prevent accidental spillages and discharges to ground during and after construction.
Foul Drainage:
All foul drainage should be directed to mains foul sewer.
An on site package treatment plant discharging to ground will not be acceptable at this site. The Agency's Groundwater and Contaminated Land team will object to any application made under the Water Resources Act 1991 for consent to discharge.
The volume of treated sewage effluent would be so large it would pose an unacceptable risk to the groundwater in the underlying aquifer and therefore to the public water supply abstraction.
The site lies in a nitrate vulnerable zone; these are designated areas where agricultural nitrate pollution of surface and ground waters is known to be high or rising.
The Environment Agency has been working hard to tighten up on farmer's use of nitrates in an attempt to reduce the amount of nitrates entering the ground and therefore the groundwater. A discharge of this volume of treated sewage effluent will only increase the nitrate loading in this area.
Surface Water Drainage:
No infiltration of surface water drainage into the ground is 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 controlled waters.
To prevent pollution of water environment.
The Agency's Groundwater and Contaminated Land team have no objection in principle to the use of infiltration systems at this site, however the following restrictions will apply:
Contaminated Land:
Drainage to ground is not acceptable at this site until results are submitted that prove that there is no contamination in the areas proposed for drainage. Drainage plans should be cross-referenced with the outcome of the contaminated land investigation.
There should be no discharge into waste material (landfills) which have been identified on site. Soakaways constructed into landfill sites will allow water to enter the waste and produce leachate, this can then produce gases and the soakaway may act as a preferential pathway to the surface. Any leachate produced may also migrate to the groundwater in the underlying aquifer, as the site lies in such close proximity to the public water supply abstraction point, this is unacceptable.
Pollution Prevention:
It is stated in the drainage strategy that pollution prevention methods (interceptors) are to be used to prevent hydrocarbons draining to ground from roads, hardstandings and car parks.
It is important to recognise that petrol interceptors require regular maintenance. Routine inspections should be undertaken at least every six months and a log maintained of inspection date, depth of oil and any cleaning that is undertaken.   Sufficient access points should be provided to allow for inspection and cleaning of all internal chambers.
The correct handling, storage and disposal of interceptor waste is vital if pollution is to be avoided. Under the Duty of Care (Waste Management), the waste producer has a duty to ensure that the waste contractor who removes the waste is registered with the Agency.
Clean uncontaminated roof water shall drain directly to soakaways entering after any pollution prevention methods.
Industrial/Commercial use of site:
Any activities producing potentially polluting run off should be sited on impermeable hardstanding areas that drain to foul sewer.
Concrete slabs should be joined together in such a manner as to not leave any paths for potential contamination to drain through. All hardstandings should be regularly maintained and cracks sealed at the earliest opportunity.
Any locations where waste is to be stored (including in skips, containers, etc) or sorted should be sited on an impermeable, hardstanding area that drains to foul sewer.
SPZ 1:
The drainage strategy states that there is to be no infiltration to ground in SPZ 1. The Groundwater and Contaminated Land agree with this statement, and all surface water drainage should be diverted out of SPZ 1 or discharge to foul sewer.
Planning Policy Statement 23: Planning and Pollution Control states that:
'In considering individual planning applications, the potential for contamination to be present must be considered in relation to the existing use and circumstances of the land, the proposed new use and the possibility of encountering contamination during development. The LPA should satisfy itself that the potential for contamination and any risks arising are properly assessed and that the development incorporates any necessary remediation and subsequent management measures to deal with unacceptable risks, including those covered by Part IIA of the EPA 1990.'
Due to the previous uses of the site, we consider that planning permission should only be granted to the proposed development as submitted if the following planning condition is imposed as set out below. Without this condition, the proposed development on this site poses an unacceptable risk to the environment and we would be obliged to object to the application.
Prior to the commencement of 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), the following components of a scheme 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 site investigation results and the detailed risk assessment (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 (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 consent of the local planning authority. The scheme shall be implemented as approved.
Prior to commencement of development, a verification report demonstrating completion of the works set out in the approved remediation strategy and the effectiveness of the remediation shall be submitted to and approved, in writing, by the local planning authority. The report shall include results of sampling and monitoring carried out in accordance with the approved verification plan to demonstrate that the site remediation criteria have been met. It shall also include any plan (a “long-term monitoring and maintenance plan”) for longer-term monitoring of pollutant linkages, maintenance and arrangements for contingency action, as identified in the verification plan, and for the reporting of this to the local planning authority.
Reports on monitoring, maintenance and any contingency action carried out in accordance with a long-term monitoring and maintenance plan shall be submitted to the local planning authority as set out in that plan. On completion of the monitoring programme a final report demonstrating that all long- term site remediation criteria have been met and documenting the decision to cease monitoring shall be submitted to and approved in writing by the local planning authority.
To ensure that the development complies with approved details in the interests of protection of the environment and harm to human health.
The relevant planning condition should not be discharged until such time as all relevant works are complete and a closure report submitted and approved by the LPA. Any construction on site should not commence until this approval has been granted
Chapter 9 - Soil Conditions and Contamination:
The Agency's Groundwater and Contaminated Land team have the following comments on chapter 9 of the EIA.
Table 7.2 does not identify all the risks posed to the groundwater in the underlying aquifer. Only made ground is identified as posing a risk to the groundwater. Landfill sites, fuel tanks, adjacent industries and aircraft parking are all potential sources which can pose a risk to the groundwater; this risk should be identified and assessed in the ground investigation report.

The Environment Agency recommends that developers should:
1)    Follow the risk management framework provided in CLR11, Model Procedures for the Management of Land Contamination, when dealing with land affected by contamination.
2)    Refer to the Environment Agency Guidance on Requirements for Land Contamination Reports for the type of information that we require in order to assess risks to controlled waters from the site. The Local Authority can advise on risk to other receptors, e.g. human health.
3)     Refer to our website at for more information.
All exploratory holes should be sited in the most appropriate locations to provide good coverage of the site and allow for investigation of potentially contaminated areas identified in the desk study.  I.e. an exploratory hole should be located in the vicinity of any fuel tanks identified on site.
Removal of material:
Contaminated soil that is excavated, recovered or disposed of, is controlled waste. Therefore, its handling, transport, treatment and disposal is subject to waste management legislation, which includes:
i.) Duty of Care Regulations 1991
ii.) Hazardous Waste (England and Wales) Regulations 2005
iii.) Waste Management Licensing Regulations 1994 (as amended)
iv.) Pollution Prevention and Control Regulations (England and Wales) 2000
v.) Landfill (England and Wales) Regulations 2002
Developers should ensure that all contaminated materials are adequately characterised both chemically and physically, and that the permitting status of any proposed off site operations is clear. If in doubt, the Environment Agency should be contacted for advice at an early stage to avoid any delays.
Foundations and Piling:
With respect to any proposals for piling through made ground, we would refer you to the EA guidance document "Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention".
The method of piling foundations for the development shall be carried out in accordance with the scheme to be approved in writing by the Planning Authority prior to any development commencing.
It is important that the scheme prevents the formation of potential pathways for the migration of contamination from the site to the underlying groundwater environment.
Fuel, Oil and Chemical Storage:
Care should be taken during and after construction to ensure that all fuels, oils and any other potentially contaminating materials should be stored (for example in bunded areas secured from public access) so as to prevent accidental/unauthorised discharge to ground. The areas for storage should not drain to any surface water system.

Where it is proposed to store more than 200 litres (45 gallon drum = 205litres) of any type of oil on site it must be stored in accordance with the Control of Pollution (oil storage) (England) Regulations 2001. Drums and barrels can be kept in drip trays if the drip tray is capable of retaining 25% of the total capacity of all oil stored.

Development and Flood Risk
 The Environment Agency has no objection to this proposal on flood risk grounds.
The risk of flooding to the development itself is low and the proposed means of surface water disposal to infiltration trenches, with some storage attenuation, would not be expected to increase flood risk elsewhere.

Please forward a copy of the full decision notice to this office, quoting our reference number.

A copy of this letter has been sent to the applicant's agent.

Yours  faithfully,

   Joseph Williamson
 Planning Liaison Officer

 cc P R C Architects