Application of LIDAR data in hydrodynamic simulation and analysis of small and medium-sized rivers in hilly areas

Flood disaster is important to the natural disaster risk sensus, which has strong destructive damage, it runs-off rapiddly and the rescue is difficult ,threatens people's life and property safety seriously . The hilly area is the key area of flood disaster with complex water system and densely-populated . Hydrodynamic model analysis can simulate the spreading speed and scope of flood to determine the risk points and key protection areas.The results of analysis have great significance for delimiting the evacuation areas, formulating emergency command plans and predicting losses of the disaster. Accuracy of topographic data affects the result of hydrodynamic simulation directly DEM used a lot for hydrodynamic model simulation. But DEM can not represent the high-pole crops and the construction and embankment along river, which reduces the accuracy of simulation and analysis.The model’s performance was evaluated in the Zhongli River.Simulate and analysis the hydrodynamic model by calculating the LIDAR data , simulates the shape of the regular channel, get the structure of hydraulic building, classifies the roughness range of surface , carries out hydrodynamic simulation analysis, and finally forms the flood risk analysis results.