Table B.18 Minimum design requirements: basin Parameter Minimum design requirements (MDRs) Infiltration Detention Length:width ratio N/A > 2:1 Side slope Side slope < 1 in 3 Side slope < 1 in 3 Longitudinal slope Bed slope < 1 in 40 Bed < 1 in 40 Maximum water depth for 1 in 100 year event 1 m 1 m Permeability of topsoil > permeability of underlying soils N/A For the 1 year 30 minute event: N/A average residence time in basin > 9 minutes flow height <100 mm velocity < 0.3 m/s Table B.19 Design assessment checklist: basin General information Site ID Asset ID(s) Basin location(s) and co-ordinates Drawing reference(s) Date of assessment Specification reference(s) Primary function(s) of basin: dual use (specify) Acceptable Comments/ Check MDR Summary details1 (Y/N) remedial actions Dimensions (Sections 13.2 and 22.2) Length (m)  Width at top and at base (m) –  Top surface area (m2) Side slope (1 in ?)  Depth maximum and minimum (m) – Freeboard (m) Longitudinal slope (1 in ?)  Inflows (Sections 13.8.1 and 22.8.1) Provide a description of the contributing catchment land use and its size (m2) Does the design include suitable silt Interception upstream of system, where required? Where required, does the design include: suitable flow spreading appropriate energy dissipation? Outfall arrangements (Sections 13.8.2 and 22.8.2)
Table B.18 Minimum design requirements: basin Parameter Minimum design requirements (MDRs) Infiltration Detention Length:width ratio N/A > 2:1 Side slope Side slope < 1 in 3 Side slope < 1 in 3 Longitudinal slope Bed slope < 1 in 40 Bed < 1 in 40 Maximum water depth for 1 in 100 year event 1 m 1 m Permeability of topsoil > permeability of underlying soils N/A For the 1 year 30 minute event: average residence time in basin flow height velocity N/A > 9 minutes <100 mm < 0.3 m/s Table B.19 Design assessment checklist: basin General information Site ID Asset ID(s) Basin location(s) and co-ordinates Drawing reference(s) Date of assessment Specification reference(s) Primary function(s) of basin: dual use (specify) Check MDR Summary details1 Acceptable (Y/N) Comments/ remedial actions Dimensions (Sections 13.2 and 22.2) Length (m)  Width – at top and at base (m)  Top surface area (m2) Side slope (1 in ?)  Depth – maximum and minimum (m) Freeboard (m) Longitudinal slope (1 in ?)  Inflows (Sections 13.8.1 and 22.8.1) Provide a description of the contributing catchment land use and its size (m2) Does the design include suitable silt Interception upstream of system, where required? Where required, does the design include: suitable flow spreading appropriate energy dissipation? Outfall arrangements (Sections 13.8.2 and 22.8.2)
c753_the_suds_manual_basin_checklist.docx