There is no requirement to demonstrate the effectiveness of SuDS schemes to authorities in providing treatment other than in making a suitable risk assessment of the treatment requirements of a site in accordance with the SuDS Manual (2015). However an objective method of indicating the effectiveness of one or more scheme options will help in demonstrating the scheme’s suitability in providing surface water treatment.
This tool is a simple way of comparing the water quality treatment effectiveness of various SuDS schemes based on the assumption of various land use loading conditions and a proportional reduction of pollutants depending on the SuDS types. The results are based on weighting of the treatment effectiveness based on the areas drained and the sequential arrangement of the SuDS units. It also takes into account the sensitivity of the receiving waters.
This tool, although different to the [SuDS treatment assessment tool] [LINK] developed for the second version of the SuDS Manual, uses the same principles and provides a simple alternative method of analysis.