Application Of 2-D Numerical Simulation To Flood Hazard Mapping Of Taipu River

China is a country with serious flood disasters. For thousands of years, Chinese people have been struggling inflexibly against the flood disaster with wisdom and courage. The experience tells that people can not control the flood thoroughly merely depending on engineering measures (such as building the embankments, reservoirs, floodgates and dams , river dredging etc.), and the best solution to it is the combination of engineering and non-engineering measures. A comprehensive prevention and management of the flood will minimize the losses, thus achieve a best benefit of flood control.With the policy of flood-fighting in China transferring from the flood control to flood management, the basic role of flood hazard mapping is becoming more and more important. Based upon the pilot project of flood hazard mapping from Ministry of Water Resources, this paper builds up a two-dimensional numerical model of Taipu River in Taihu Lake Basin adopting hydraulic methods. It gives a good simulation of flood routing after dam break which is referenced to flood hazard mapping.By fitting the measured data from the Taipu river, a more proper way of calculating weir flow coefficient is found to analyze discharge capacity for Taipu gate. Some efforts are made to get the topographic data about highways, railways, cross sections of the river and the dams for pretreatment; hydrological data is used to acquire different discharges and water levels under certain flood frequencies by data collation and analysis.A detailed introduction of the theory and using method are given about the Delft3D-FL0W, and it is also the first time to apply the Delft3D -FLOW software into simulation of the two-dimensional flood routing in flood plain. The two-dimensional simulation is combined with one-dimensional flow model using side wire flow. Usingthe standard drying and flooding algorithm in Delft3D-FLOW, this model gives a good simulation of flood routing under different schemes of dam breaks. These computational results are used as inputs of ArcGIS to make flood hazard maps and to give a primary assessment of the loss caused by flood, which can provide useful reference to the job of flood control and disaster mitigation.