Critical Drainage Area (CDA)
Critical Drainage Areas are discrete geographic areas, usually a hydraulic catchment, where there are multiple and interlinked sources of flood risk. If your site falls within a CDA, consult a drainage expert before submitting your planning application. The GOV.UK flood risk and coastal change guidance explains how CDAs are identified and managed by local authorities.
Case Example
If your site is in a CDA in London, the local council will likely insist that your new drainage system is much more restrictive to protect over-burdened local pipes.
Building in a CDA? Rida Reports prepares FRA-compliant drainage strategies for approval.