The East Sussex Small Scale Sustainable Drainage Systems (SuDS) Tool has been developed by Royal HaskoningDHV for East Sussex County Council. It is designed to assist planning authorities and developers in assessing the suitability of SuDS provision within small scale development proposals. The main focus of the tool is to enable planning authorities to ensure that the flood risk requirements for SuDS are met by development proposals.

It does not give definitive attenuation volumes that will be achieved by a specific SuDS solution and a final design will be required to determine the actual performance of the proposed system.

• This tool has been designed for assessing development proposals in East Sussex. It is not suitable for use in other geographical areas as the hydrological calculations are specific to this area.
• Where a developer proposes infiltration as part of the SuDS techniques for a site, they will be required to provide appropriate infiltration test results and calculations to support their application.
• The tool is designed for small scale development up to a maximum of 5,000m² of residential development or 10,000m² of non-residential development. Major development would need a more comprehensive SuDS design to be developed.