Stormwater management model based cost-benefit analysis of integrated grey-green infrastructure scenarios

This study promotes the integration of ecological green infrastructure with traditional gray infrastructure to tackle urban water management challenges and safety issues. Using the Storm Water Management Model (SWMM), we simulated runoff control in Beijing Tongzhou District Sponge City Pilot Area across 15 gray-green infrastructure scenarios and identified the optimal strategy through a cost-benefit analysis focusing on scenarios that meet runoff control standards. A cost-benefit evaluation framework was developed for gray-green infrastructure projects, employing payback period and net present value methods to assess cost-effectiveness. Findings revealed notable operational benefits, particularly in temperature and humidity regulation, which accounted for 88% of the total benefits. A standout scenario with a rapid payback period of 7.16 years and a net benefit of 1957.7 million yuan was highlighted. The research provides a holistic assessment, integrating environmental, ecological, and economic aspects of gray-green infrastructure, offering insights for effective green infrastructure deployment and evaluation in sponge city construction. (Figure presented.)