Comparative Analysis of Urban Reservoir Dam Break Simulation Under Extreme Rainfall
With the objective of investigating the changes in flood hazard under two conditions before and after the extreme rainfall coupled with the upstream reservoir failure in the city,the Erqi,Zhongyuan,Jinshui and Huiji districts of Zhengzhou were identified as the study areas,and the design storm was derived by combining the Chicago rainfall type and long-duration rainfall intensity formulae.Based on the measured data of Zhengzhou heavy rain occurred on July 20,2021,the characteristics of runoff yield and convergence in the study area were deduced,and the response relationship between extreme rainfall and flood process was established.On this basis,a two-dimensional dam-break flood evolution model was built for the Jiangang Reservoir in Erqi District,Zhengzhou City,to compare and analyze the water regime under the two operating conditions.The results show that the inundation range under the rainfall-coupled dam-break condition is larger compared to dam-break only,where the maximum water depth and flow velocity at various points within the main increased inundation range are at a lower level.On both sides of the river,the inundation range of water depth,flow velocity and flood severity is roughly the same under the two working conditions.However,the inundation depth and flow velocity increase more under the condition of rainfall coupling dam failure in the low-lying study area,and the water depth of the water-prone point increases by about 0.6 m,and the water surface line of the selected section increases by about 1 m.
urban reservoirsdam break coupled with rainfallextreme rainfalldepth of inundationJiangang ReservoirZhengzhou City
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