Strategic flood risk assessment
All local planning authorities are required to prepare a Strategic Flood Risk Assessment (SFRA) for their areas in order to assess the risk from flooding from all sources and as the basis for applying the ‘sequential’ and exceptions’ tests to potential development sites identified for inclusion in the Local Plan. In September 2014, the Council jointly procured consultants to prepare an SFRA for each of the partner Boroughs located within the River Wandle catchment (Sutton, Croydon, Merton and Wandsworth).
The SFRA Level 1 Report (December 2015) shows:
- areas at risk from fluvial (river) flooding falling with EA Flood Zone 1 (low risk), Flood Zone 2 (medium risk), Flood Zone 3a (high risk) and Flood Zone 3b (functional floodplain) based on updated EA modelling for the River Wandle, Beverley Brook and Pyl Brook;
- areas at high, medium, low and very low risk of surface water flooding based on the EA’s updated flood map for surface water (uFMfSW);
- surface water drainage ‘catchments’ and hotspots; and
- areas susceptible to groundwater flooding and areas which have experienced sewer flooding
The Level 1 Report contains planning policy recommendations and a site assessment database for the purpose of undertaking the ‘sequential test on potential development sites. The findings of the sequential test are set out in the Sustainability Appraisal (SA) Report on Sutton’s draft Local Plan which has been published for public consultation between 9 January and 24 February 2017.
SFRA Level 2 Report
Sutton’s amended SFRA Level 2 Report (March 2017) provides technical information and guidance on proposed site allocations located within flood risk areas in order to show how they could be developed in line with the Government’s ‘Exception Test’ and therefore ensure that “the development will be safe for its lifetime taking into account the vulnerability of its users and that it won’t increase flood risk elsewhere”.
The SFRA level 2 Report forms an important part of Sutton’s Local Plan evidence base and should be used to inform the preparation of site specific flood risk assessments (FRAs) by developers.