Deconstructing the sustainable drainage management train in terms of water quantity - preliminary results for coventry, UK

The potential water quantity benefits of various sustainable drainage system (SUDS) management trains compared to conventional pipe-based drainage systems are examined using the commercially available software WinDes® to model a site at Prior Deram Park, Coventry, UK, by investigating its response to a 1 in 100 years 30, 360, and 720 min winter rainfall event. The site is currently subject to a regeneration plan whereby the Park will be replaced with 250 houses. The housing layout was designed in ArcGIS and transferred to WinDes® and flood hydrographs of the likely outflow from each system simulated. The outputs from each system were then compared and it was found that an 88% reduction of peak flow was achieved using a SUDS management train that consisted of green roofs, porous paving, swales and dry detention ponds in comparison to pipe based drainage systems. The type of SUDS also appears critical; detention ponds can reduce peak flow by 82.9% when compared to systems without detention ponds. It is however likely that some form of flow control will be required at the outflow point as the peak runoff generated was significantly higher than acceptable values of 23 L/s for the site.