Flood mitigation performance of low impact development technologies under different storms for retrofitting an urbanized area

Low impact development technologies (LIDS) have been reported as alternatives to mitigate urban water related hazards, particularly for urban flooding. However, the effectiveness of LIDs on flood mitigation is still not well understood. This study assessed the mitigation extent of urban flooding by LIDs for retrofitting an urbanized area at a feasible level using a hydrological model. A range of storms with different rainfall durations and amounts from intensity-duration-frequency curves were used to evaluate the hydrological performances of LIDs. The results indicated that LIDs were effective alternatives to mitigate urban flooding in the urbanized area. Surface runoff and peak flow decreased by 18.6-59.2% and 8.0-71.4%, respectively. However, the flood mitigation performance decreased markedly with the increase of rainfall amount. Although LIDs were less effective in flood mitigation during shorter and heavier storms, the performance was better with the increase of rainfall duration. This research provides an insight into flood reduction capabilities of LIDs under different rainfall characteristics for retrofitting built up areas, which is useful for urban storm management. (C) 2019 Elsevier Ltd. All rights reserved.