Drainage Assessment Form
Drainage Assessment Form (DAF)
All major planning applications should be supported by a completed Drainage Assessment Form (DAF) in order to demonstrate that the Council’s minimum performance standards for sustainable drainage (SUDS) have been met in line with Policy 5.12 of the London Plan, the Mayor’s Supplementary Planning Guidance (SPG) on Sustainable Design and Construction and Policy DM7 of Sutton’s Site Development Policies DPD.
All major residential and non-residential developments should aim to achieve greenfield runoff rates and volumes for all storm events up to and including the 1 in 100 yr 6‐hr storm event (taking account of climate change) through application of the Mayor’s drainage hierarchy.
The DAF provides a template for the run‐off calculations and further details that are required alongside site drawings and other relevant drainage information. Please note that although the DAF requests information on other sources of flood risk (such as fluvial, groundwater and sewer flooding), it does not in itself constitute a site specific Flood Risk Assessment (FRA) which should be prepared for all developments located within Flood Zones 2 and 3, major developments exceeding 1 hectare in Flood Zone 1 and all developments within a critical drainage area (CDA). Where appropriate, both documents should be submitted.
The new SUDS arrangements
The new arrangements for approving and implementing SuDS through the planning system took effect on 6 April 2015 through the implementation of Schedule 3 of the Flood and Water Management Act 2010. While ultimate responsibility for approving and securing the implementation of SuDS measures proposed as part of new developments remains with the local planning authority (LPA), the lead local flood authority (LLFA) is now a statutory consultee on all major planning applications. As part of these changes, new ‘non‐statutory’ national SuDS standards have been introduced and the Government’s National Planning Practice Guidance (NPPG) has been strengthened to make clear that SuDS should be delivered in all new developments.
Further Information on SUDS and Local Flood Risk management For further information on the new procedures for assessing SUDS schemes proposed as part of major planning applications and the Council’s approach to local flood risk management as a ‘lead local flood authority (LLFA), please follow the following links: