Abstract:Considering the efficiency and visualization of flood risk information management system and the difficulty in coupling gate breaking process and flood propagation, the flood propagation process at Taipu gate due to breaking can be simply computed based on water volume balance; and a coupled onedimensional and twodimensional hydrodynamic model is established to simulate flood propagation in the river channel and flooded area respectively, with one dimensional hydrodynamic model used in Taipu River channel to provide breach flow discharge at three possible embankment breach locations when Taipu Gate in failure as the boundary conditions for the two dimensional hydrodynamic model. The simulation results show that the established model, a simple model to deal with Taihu and river channel at gate breach and a coupled onetwodimensional model for river channel and flooded area respectively, is valid, efficient and practical for flood risk mapping of Taipu Gate.