Coupling a Distributed Time Variant Gain Model into a Storm Water Management Model to Simulate Runoffs in a Sponge City

The storm water management model (SWMM) has been used extensively to plan, implement, control, and evaluate low impact development facilities other drainage systems solve storm-related problems in sponge cities. However, the calibration of SWMM involves a variety sensitive parameters may bring significant uncertainties. Here we incorporated distributed time variant gain (DTVGM), with simple structure few parameters, into (called DTVGM-SWMM) reduce complexity but keep mechanistic representation hydrological process. DTVGM runoff module were calibrated validated using Nash–Sutcliffe efficiency (NSE), based on measured data results SWMM. It was then coupled routing estimate catchment runoffs outflows. Finally, performance evaluated NSE (0.57~0.94), relative errors flow depth (−7.59~19.79%), peak rate (−33.68~54.37%) under different events. These implied that DTVGM-SWMM simulations generally consistent those control group, underperformed simulating flows. Overall, proposed framework could reasonably runoff, especially outflow process urban catchment. This study provides reliable method for stormwater simulation.