Study On Small Watershed Flood Risk Assessment And Early Warning Technology Based On HEC-HMS

Our country is a mountainous country, in recent years, the climate became gradually harsh, flash floods occurs frequently, at the same time, due to the rapid development of society and population growth, flash floods have more serious disasters. It not only caused huge economic losses, but also cause injury or even death, pose a great threat to life, it is imminent to prevent the flood disasters.This paper starts from non-structural measures of mountain flood prevention, it chooses Xiang’ ning, Shanxi Basin as an example, considering the topography and hydrometeorology of Xiang’ ning basin, analysis the hydrological characteristics of this basin,this paper constructs topology of Xiang’ ning Basin, establish distributed hydrological model of Xiang’ ning Basin in HEC-HMS. According to the collected historical rainfall- runoff data, it get the most suitable model and optimal parameters. On the basis of the optimal solution, the study should sort out historical rainfall data, collect the section of important village, simultaneously disaster level and risk level is collected, with the reverse Simulation, it can get the village ready to move indicators and immediately transferred indicators; by means of analysis of historical rainfall data and real-time soil moisture saturation, draw the scatter plot about Saturation of soil moisture and rainfall accumulation in 1h、2h、3h and 6h. The dynamic critical rainfall discriminant function is be determined by W-H algorithm. On the basis of the optimal solution, according to analyze the basin rainstorm factor, the population factor, factor houses, terrain factor, flash floods factor, road factor, flooding factor, the final risk profile is drawn by overlay analysis.Through the study, it provide practical guidance to flash Flood Warning and Forecasting, mountain flood prevention and risk transfer flash of Xiang’ ning basin.