Cherwell District Council
Planning Policy
Bodicote House White Post Road
Bodicote
Banbury
OX15 4AA

Our ref:	WA/2014/118995/01-L01
Your ref:	14/01740/REM

Date:		18 November 2014

Dear Mr Lewis,

RESERVED MATTERS TO OUTLINE APPLICATION (10/01642/OUT) - ERECTION OF 103 DWELLINGS WITH ASSOCIATED CAR PARKING, INFRASTRUCTURE, LANDSCAPING AND OTHER WORKS   
HEYFORD PARK, CAMP ROAD, UPPER HEYFORD.      

Thank you for consulting us on this matter. We received the letter on 24 October 2014 and we are now in a position to respond.

Environment Agency Position

In the absence of an acceptable Flood Risk Assessment (FRA) we object to the grant of planning permission and recommend refusal on this basis for the following reason:

Reason

•	The applicant has not demonstrated that the storage volume required to attenuate surface water run-off from the critical 1 in 100 chance in any year storm event, with an appropriate allowance for climate change, can be provided on site.
•	The applicant has not demonstrated that sustainable drainage systems (SuDS) will be used on site to provide storage for surface water generated on site, in line with the National Planning Policy Framework paragraph 103, that requires development to give priority to the use of SuDS.
•	The applicant has not demonstrated that the peak discharge rate for all events up to and including the 1 in 100 chance in any year critical storm event, including an appropriate allowance for climate change, will not exceed that of the existing site. This may increase the flood risk on site and in surrounding areas.
•	No specific information has been submitted showing or expaining how the proposed development will be drained in accordance with an overall drainage strategy for the site. Drawing drwg: B.0285_58L (29th May 2014) indicates that parts of the site are to be layed as permeable paving, however the key is not clear enough to determine which areas are proposed to be permeable and which are not.   

Overcoming our objection

Surface water for up to the 1 in 100 chance in any year storm event, including an allowance for climate change, must be safely contained on site. It may be acceptable for limited flooding to occur in parts of the site if buildings are not affected by flooding and the site can be safely navigated by users. Where this flooding will be within roads or pathways, the applicants must ensure that safe access and egress is still available.

The applicant must demonstrate through their surface water strategy that the proposed development will not create an increased risk of flooding from surface water 

The surface water strategy must demonstrate that the use of SuDS has been given priority over more traditional pipe and tank systems, providing justification where it is not considered practicable to utilise SuDS on site. The surface water strategy should be carried out in accordance with the National Planning Policy Framework and PPS25 Practice Guide giving preference to infiltration over discharge to a watercourse, which in turn is preferable to discharge to surface water sewer.

We also request that drawing drwg: B.0285_58L (29th May 2014) is revised to make it clear which sections of road are to be permeable and which are not. 

Advice to LPA/Applicant

Guidance on the preparation of surface water strategies can be found in the Defra/Environment Agency publication "Preliminary rainfall runoff management for developments". Guidance on climate change allowances can be found within the National Planning Policy Framework Technical Guidance.

The applicant should, as part of the surface water strategy, demonstrate that the requirements of any local surface water drainage planning policies have been met and the recommendations of the relevant Strategic Flood Risk Assessment and Surface Water Management Plan have been considered. 

The CIRIA publication ‘C635 Designing for exceedance in urban drainage— Good practice’ contains advice on surface water conveyance and storage. The document can be accessed at www.ciria.com/suds/ciria_publications.htm

Surface water run-off should be controlled as near to its source as possible through a sustainable drainage approach to surface water management (SUDS). SUDS are an approach to managing surface water run-off which seeks to mimic natural drainage systems and retain water on or near the site as opposed to traditional drainage approaches which involve piping water off site as quickly as possible. SUDS involve a range of techniques including soakaways, infiltration trenches, permeable pavements, grassed swales, ponds and wetlands. SUDS offer significant advantages over conventional piped drainage systems in reducing flood risk by attenuating the rate and quantity of surface water run-off from a site, promoting groundwater recharge, and improving water quality and amenity.

The variety of SUDS techniques available means that virtually any development should be able to include a scheme based around these principles.

Further information on SUDS can be found in:

• PPS25 Practice Guide
• CIRIA C522 document Sustainable Drainage Systems – design manual for England and Wales
• CIRIA C697 document SUDS manual

Advice to applicant

Our mapping indicates there is an ordinary watercourse along the southern boundary of the site. Erection of flow control structures or any culverting of an ordinary watercourse requires consent from the Lead Local Flood Authority which in this instance is Oxfordshire County Council . It is best to discuss proposals for any works with them at an early stage.

Yours sincerely,

Mr Jack Moeran
Planning Advisor

Direct dial 01491 828367
Direct e-mail planning-wallingford@environment-agency.gov.uk

cc Pegasus Planning Group