Abstract: In order to solve the urban waterlogging caused by  rainstorm and provide technical support for emergency management, the SWMM-CCHE2D coupled model was established considering the urban rainstorm process and the characteristics of the sponge surface, combined with the principles of urban hydrology and hydraulics and the Chicago rain pattern. With high-precision topographic data and real-time monitoring data of rainfall and runoff, SWMM stormwater model was used to simulate the runoff of sponge city under rainstorm conditions, coupled with high-precision two-dimensional hydrodynamic model CCHE2D to simulate the corresponding waterlogging conditions. This method is easy to implement. The results show that under heavy rainstorm, the runoff and confluence in Tongzhou has the feature of slow seepage and collection. Major LID facilities have good effects on improving the runoff reduction rate by 9.0%-40.6% and alleviate the inland flooding. Among the design rainstorm, the effect on the five-year return period is the most significant. For all LIDs with the 100-year return period, the effect of bioretention is relatively significant up to 28.4%. The pavement permeability and the effect of green land are also good.

Key words: SWMM-CCHE2D, heavy rainstorm, sponge city, inland flood modeling