Application Of HEC-HMS Model In Flood Forecast Of Upper Yinghe River Basin

Mountain flood disaster is one of the major natural disasters that cause casualties in China,and it’s defense work is also the focus and difficulty of flood prevention and disaster reduction.Dengfeng City is located in the middle of Henan Province,in the transition zone between the eastern Henan Plain and the Songshan Mountains.The terrain in the hilly areas of the country is complex,the rainfall is unevenly distributed in space and time,and floods are prone to occur.This article takes the Luohe River and its tributaries in Dengfeng City,Henan Province as the research object,and takes the watershed area controlled by the Gaocheng Hydrological Station in Dengfeng City as the research area.By using geographical data such as DEM,land use,and soil types,a digital model of the watershed is constructed..At the same time,based on the measured rainfall and runoff data in the basin as input data,the flood prediction models of the HEC-HMS model and the spatiotemporal variable source mixed runoff(SKBY)model were established to explore the applicability of the two models in the Gaocheng Basin.The main work and results are summarized as follows:(1)Statistical analysis of hydrometeorological conditions such as precipitation and runoff in the Gaocheng Basin,the results show that the inter-annual difference in rainfall in the study area is large,the annual distribution of rainfall is mainly concentrated in the flood season,and short-term concentrated heavy rainfall is the main factor inducing flood disasters;Affected by precipitation,historical floods occurred in July and August,with a multi-year average runoff of5.87×10~8m~3.(2)Based on the river basin digital elevation model and geographic information system,the HEC-GeoHMS extension module of ArcGIS toolbox is used to preprocess the DEM data to generate the river network and sub-watershed,extract the sub-watershed characteristic parameters,and construct a successful digital model of the watershed.The Tyson polygon method was used to calculate the weight of the sub-watershed in the rainfall station,and then the surface rainfall was calculated.Use the HEC-HMS software to create a HEC-HMS model of the Gaocheng basin;The hydrological response unit based on geomorphic unit lines was constructed by using stormwater and flood analysis software(FFMS)in small watersheds,and input of geographic data and meteorological data to build a mixed runoff model of spatiotemporal sources in the study area.(3)From the long series of data of the Gaocheng Basin,10 typical rainfall runoff processes with good representative were selected,and HEC-HMS model and SKBY model were used to simulate the rainfall runoff process,among which 7 were used for model parameter calibration and 3 for model verification.The simulation results show that both models have good applicability in Gaocheng Basin.(4)The rate of the HEC-HMS model is 85.7%of the regular flood field pass rate,the average determination coefficient DC is 0.75,and the simulation accuracy is Class A and Class B,respectively;The qualified rate of flood simulation in the verification period was 66.7%,the determination coefficient DC was 0.74,and the simulation accuracy was all equal to Class B.The SKBY model has a regular flood pass rate of 79%,the average determination coefficient DC is 0.71,and the simulation accuracy is Class B;The qualified rate of flood simulation in the verification period was 66.7%,the determination coefficient DC was 0.78,and the simulation accuracy was C and B,respectively.