Flood Warning Indicators For Small Watershed In Jinxian County Based On HEC-HMS Model

In order to cope with the occurrence of flood disasters and the losses caused by them,China has also been committed to the study of flood disasters in recent years.Up to now,the research technology of flood disasters in China has been relatively mature.Floods often occur in mountain areas and some watersheds in our country,and have had a serious impact on the economy.Due to the lack of hydrological data,water conservancy equipment and early warning facilities in the basin,many areas are frequently affected by flood disasters.According to the HEC-HMS hydrological model,this study simulates the hydrological process of the small watershed of Sanchagang in Jinxian County,and studies the hydrological process of the small watershed to find out the flood characteristics.Combined with the comprehensive analysis of rainfall data,this study further discusses the early warning indicators of the study area.The main research of this paper is as follows:(1)The basic situation of the research area is briefly described,the significance and background of the research are clarified,and relevant data and documents are consulted to analyze the research situation of HEC-HMS model and various other models at home and abroad.The hydrology,rainfall characteristics and water system of the study area are collected:the annual and seasonal rainfall in this area is very uneven,with a multi-year average rainfall of 1712 mm.The main rainfall period is from April to June,accounting for 49.3%of the total annual rainfall.The overall flow rate in the study area is not large and the flow rate is average.However,the disastrous hydrology is relatively low.Vulnerable to floods.(2)Using the GeoHMS module in ArcGis,the 30*30 DEM(i.e.digital elevation data)is processed to fill in depressions,flow direction,flow rate,sub-basin division,etc.,so as to obtain the digital basin of the corresponding research basin.Furthermore,basinization is carried out on the digital watershed to obtain the basin file required by HEC-HMS model.(3)Import the above basin basin file,create time series,meteorological model,etc.and construct HEC-HMS model.Three models were selected and 5 floods were simulated.The simulation results of the three schemes are compared to find out a relatively better scheme for further research.(4)Determine a good simulation plan,select typical flood 20180706 flood warning index analysis.Based on the measured river section data and Manning's formula,the water level-flow relationship curve of the study area is deduced,and the disaster water level of the study area is compared to determine the critical flow corresponding to the disaster water level.The HEC-HMS model is used to simulate the hydrological process,and the early warning indexes of dry,normal and wet soil are obtained under different soil moisture contents.