Sustainable Drainage Systems: Guidance for Devon
We advise all applicants intending to submit a planning application for a major development to refer to our Sustainable Drainage Systems: Guidance for Devon (2023) document.
When submitting a planning application of this nature, we require applicants to provide a surface water management plan which demonstrates how surface water from the proposed development will be disposed of in a manner that does not increase flood risk elsewhere, in accordance with the principles of SuDS.
Groundwater monitoring policy
When any infiltration based surface water drainage system is proposed, DCC will require groundwater monitoring to ensure the functionality of the proposed infiltration devices. Groundwater monitoring will enable the determination of 1m of free space between the base of the infiltration device and the maximum groundwater level as per BRE Digest 365 and Ciria SuDS Manual C753 (2015). Ideally a year’s worth of groundwater monitoring should be undertaken, however, if there are time constraints, we would accept monitoring undertaken between the start of November and the end of May. This is provided that the results clearly indicate that the maximum groundwater peak level has been achieved and has declined for two consecutive months. Ideally, two readings per month should be undertaken.
The number and location of boreholes required will depend on the number of infiltration devices and their location on the site.
Boreholes should be drilled to a depth of at least 2m below the base level of the infiltration device.
DCC has produced a SuDS Pro Forma for planning applications, which should be read in conjunction with DCC’s Sustainable Drainage Systems: Guidance for Devon. The checklist is available here to be downloaded.
Last updated: April 2019