Optimization of wetland restoration siting and zoning in flood retention areas of river basins in China: A case study in Mengwa, Huaihe River Basin

Summary Wetland restoration in floodplains is an ecological solution that can address basin-wide flooding issues and minimize flooding and damages to riverine and downstream areas. High population densities, large economic outputs, and heavy reliance on water resources make flood retention and management pressing issues in China. To balance flood control and sustainable development economically, socially, and politically, flood retention areas have been established to increase watershed flood storage capacities and enhance the public welfare for the populace living in the areas. However, conflicts between flood storage functions and human habitation appear irreconcilable. We developed a site-specific methodology for identifying potential sites and functional zones for wetland restoration in a flood retention area in middle and eastern China, optimizing the spatial distribution and functional zones to maximize flood control and human and regional development. This methodology was applied to Mengwa, one of 21 flood retention areas in China’s Huaihe River Basin, using nine scenarios that reflected different flood, climatic, and hydraulic conditions. The results demonstrated improved flood retention and ecological functions, as well as increased economic benefits.