A GI-based framework for designing stormwater response programs in priority urban areas

Study region Kaifu District, Changsha City, Hunan Province, China. Study focus This paper proposes a framework for designing and optimizing flood control solutions for stakeholder-defined priority areas and applying it to a region to assess its application and validate its effectiveness. The area of green infrastructure within each sub-catchment serves as the decision variable, representing the type, size, and optimal placement location. Life cycle cost and runoff control rates are set as the optimization objectives for the NSGA-II algorithm, and the layout of green infrastructure is iteratively updated based on SWMM simulation results. Ultimately, an optimized strategy for flood mitigation in priority areas is derived. New hydrological insights for the region The study found that the number and distribution of areas playing a critical role in flood mitigation within priority zones — referred to in the paper as “main impact zones” — are primarily influenced by node overflow volumes surrounding the priority areas and the runoff control characteristics of green infrastructure; variations in storm intensity may also cause changes to these areas. Given limited available land area, the selection of which sub-catchment area will yield better results is also influenced by these three factors.