Abstract: With the acceleration of urbanization, urban flood and waterlogging disasters are frequent. In order to accurately analyze the impact of flood disasters on the current flood control system and make corresponding measures for flood control and disaster reduction, the lower reach of Ling River along the southeast coast is taken as the research area in this paper. We construct a hydrodynamic coupling model based on Saint-Venant equation, and simulates the process of river burst flood in real time. Considering the factors of the study area such as topography, meteorology, hydrological data, hydraulic engineering, underlying surface conditions and so on, in the coupling connection of one-dimensional river network model and two-dimensional hydrodynamic model, the interactive inundation of water flow inside and outside the river channel in real terrain can be restored to the greatest extent. With the help of typhoon and rainstorm data in the study area, the one-dimensional and two-dimensional coupled hydrodynamic models established are calibrated and validated. The tested models can be used to simulate the real-time submergence of design flood and historical flood in Coastal cities along the lower reaches of Ling River. The results show that the model has good accuracy in simulating the real-time flood routing process under complex terrain conditions, and the error between the calculated value and the measured value of typical section water level along the river system is less than 0.1 m.

Key words: the lower reaches of Lingjiang River in Taizhou, Zhejiang, coupled hydrodynamic model, real-time simulation, flood routing