This Tesco store is a 2.5 ha site, 1.8ha of which is impermeable. The roof discharges directly to the watercourse. The car park runoff flows though the sub-base and is passed to a wetland via a pipe.
The store employs contractors to do maintenance.
The monitoring undertaken by the Environment Agency has shown in 11 storms the average time between the peak in rainfall and the peak in runoff from the carpark is 52 minutes and the average % outfall from the carpark compared to rainfall is 40%.
The following SuDS components were used on this site: