A SWMM-based evaluation of the impacts of LID and detention basin retrofits on urban flooding

Keywords: Detention basin, retrofit, urban flooding, LID, BMP
Abstract Type: Virtual Paper Abstract

Abstract

Urban flooding has become a common issue worldwide. Low impact development (LID) practices are increasingly used in urbanized areas as stormwater management techniques to mitigate the impacts of urbanization and attenuate the risk of urban flooding. The existing literature has focused on the investigations of effects of LID and the optimization strategy such as the selection size, type and location of the LID. However, there is a lack of the studies on the integration of conventional stormwater control measures such as detention basins and retrofitting techniques. Furthermore, the impacts of retrofitting the existing detention basins are rarely studied. The aim of the paper is to develop a SWMM model and examine the impacts of detentions and their retrofits in two urbanized catchments. In addition, the impacts of various stormwater management techniques under different return period storm events (1-year, 2-year, 5-year, 50-year and 100-year) are explored. Five scenarios are designed to compare the performance of integrating detention basin, detention basin retrofitting and LID practices in peak flow reduction, peak time delay and duration of critical flows. The results showed that detention basin and detention basin retrofits are more effective in reducing peak flow and delaying peak time. The performances of LID practices are better in smaller rainfall events than in larger storm events. The integration of detention basin retrofits and LID practice can contribute to 71.24% to 97.71% peak flow reductions in the designed storms.