Study on rainstorm waterlogging on urban community scale based on rainstorm scenario simulation

Under the background of global warming, urban torrential rains and waterlogging disasters frequently occur, especially affecting the eastern coastal cities. According to the classification of the disaster-causing factors of the rainstorm and waterlogging, based on the SWMM (Storm Water Management Model), a typhoon and non-typhoon rain scenario waterlogging response simulation model was constructed in the Ningbo area, and the characteristics of typhoon rain waterlogging and non-typhoon rain waterlogging were compared and analyzed. The results show that: (1) Typhoon and non-typhoon rains have significant differences in change trend, distribution characteristics, and time history distribution. (2) In the typhoon rain scenario, the water level and flow of the river are mainly affected by the tide level, and backflow occurs at the high tide level. In the non-typhoon rain scenario, the river level and flow are mainly affected by rainfall and increase with the increase of the return period. (3) In typhoon and non-typhoon rain scenarios, the number and level of sub-catchments where waterlogging occurs in the study area increase with the increase of the return period, and the water accumulation areas are distributed from scattered to continuous, with a maximum of 17 sub-catchments waterlogging occurring in the area, accounting for 80% of the total waterlogging area. In a typhoon rain scenario with the same return period, the drainage pipe network has a higher load rate, a greater node flood, a heavier waterlogging, a longer duration of water accumulation, reaching more than 10.7 hours and a deeper depth of water accumulation exceeding 67 cm . This study enriches the methods of rainstorm flooding research and provides a reference for community scale waterlogging research.