Effects of low-impact development practices for flood events at the catchment scale in a highly developed urban area

Abstract

Because conventional responses to urban flooding, such as the extension of sewer conduits, are basically incompatible with recent trends of sustainable development, it is desirable to restore the natural hydrological cycle and maximize the infiltration capacity of a site at the source of flooding. Thus, low-impact development (LID) practices have frequently been suggested as adaptation strategies to local climate change. Studies have demonstrated the potential effects of LID, but they have not quantified and verified the extent of its capacity to mitigate the effects of actual floods. Therefore, this study set up catchment-scale sites located at the boundary where rainwater is treated in an urban area and evaluated the impacts of two types of LID using the Storm Water Management Model (SWMM) based on actual flood events during the wet season. The results showed that LID could reduce the runoff volume, peak flow, and inundation volume compared with conventional development. This study also used and demonstrated the implications of sensitivity testing and model updating to increase the correlation between the real system and the modeled site; therefore, the results can be used as a reference to assess the effectiveness of green space when planning urban redevelopment and regeneration projects where sewer systems already exist.