Application Of HEC-HMS Flood Forecasting Model For Dazhan Reservoir Basin

With the change of global climate,the flood disaster threatens people's life and property security and the sustainable development of society more and more.Based on Dazhan reservoir watershed as the research object,using geographic information system(ARCGIS),constructing digital drainage basins,and rainfall runoff relations based on the underlying surface conditions,established the HEC-HMS Dazhan reservoir basin Flood Forecasting model,aiming at the key parameters of runoff module CN value,the choice of model parameter was established.In addition,the Dazhan flood forecasting model was used to forecast the flood of the designed rainstorms with different typical frequencies,so as to provide a scientific theoretical basis for the Forecasting of Flood disaster in this area.The main conclusions of this paper are as follows:(1)Construction of digital watershed of dazhan reservoir.Firstly,the basic conditions of dazhan reservoir basin,such as natural geography,hydrometeorology,soil type and land use type,are analyzed.Then,according to the river network situation of dzhan reservoir basin,the dzhan reservoir basin is generalized into 27 sub-basins,14 river segments and 1 reservoir by using the hec-geohms module in ARCGIS and 30M 30M digital elevation data,and the digital basin of dzhan reservoir is constructed.(2)Establishment of flood prediction model for dazhan reservoir basin.Based on the characteristics of rainfall runoff in the dazhan reservoir basin,SCS curve method was used to determine the runoff yield in the sub-basin,SCS unit line method was used to determine the confluence in the sub-basin,and the moving wave method was used to determine the confluence in the river.(3)Parameter study of Dazhan flood forecasting model.For runoff yield model ?CN value,the key parameters of SCS curve method based on the calculation principle of the SCS curve method,established the different soil types and land use type CN value as a function of production flow,using LINGO CN value rate model is established,and selects the seven historical flood data of different soil types and land use type of CN value for the calibration and verification,the effect is better;The parameters in the confluence model are estimated first,and then calibrated and verified with historical flood data.Through analysis,the model can forecast the flood well.(4)Application of flood prediction model.The flood forecasting model is used to forecast the inflow and outflow process of the reservoir and the discharge process at the outlet of the dazhan reservoir basin.