Evaluating the effect of urban flooding reduction strategies in response to design rainfall and low impact development

Rapid urbanisation and climate change-induced watershed hydrologic alteration have increased urban flooding risks. As a strategy for urban flood control, low impact development (LID) practices focus on promoting the infiltration and detention of stormwater runoff. A modelling-based study was conducted to analyse LID performance in urban flooding reduction. Two-dimensional simulations were conducted to visualise the flood risk under different precipitation scenarios and LID schemes. An integrated evaluation system based on life-cycle cost analysis, the analytic hierarchy process, and regret decision theory were applied to assess the LID performance in multiple aspects. The results indicated that the LID practices achieved runoff control and flood mitigation to some extent, especially under mild rainfall events. According to the integrated evaluation, urban flooding risk could be sufficiently reduced with the LID combination of bioretention, infiltration trenches, and rain barrels in the given area.