The Analysis Of Spatial Variation Of Flood Risk In Jinjiang Watershed Based On The Simulation Of HEC-HMS

Flood hazard is one of the most important and frequent disasters in the world.In order to make effective disaster prevention,we need to determined the spatial distribution of flood and delimit the flood high risk area in the basin.In this study,we chose Jinjiang watershed as the study area to conduct three aspects of research :(1)We came up with the method of multi-sites calibration and validation to calibrate the key parameters,the initial loss rate(λ)and the flood wave velocity(V),in Jinjiang watershed.The initial loss rate(λ)and the flood wave velocity(V)were calibrated in each sub-area with approximate circulation method to find out the temporal and spatial variation of them.(2)We obtained the occurrence time of the maximum flood peak flow of Shilong station in each subbasin from modeling result.We Used Pearson-Ⅲ curve to make requency analysis of the flood in each subbasin.Then we analyzed the spatial variation of flood Jinjiang watershed.(3)According to the results of spatial variation of flood,population and property,we determined the high risk area of flood hazard in Jinjiang watershed by using analytic hierarchy process.The results showed that:(1)The HEC-HMS model constructed by the multi-sites calibration and validation makes full use of the hydrological observation data,which can better reflect the changes of hydrological processes in different sections of the basin.(2)The spatial variation of the initial loss rate was influenced by the land use and water conservancy project,and the temporal variation was dependent on initial discharge.The spatial variation of flood wave velocity was related to the average slope of watershed while the temporal variation was related to largest 6 h areal rainfall and upstream runoff.(3)Except for some multi-peak flood processes,the flood simulation results of HEC-HMS model are generally good with small errors,which can be applied to the analysis of spatial changes of flood in the basin.(4)We can get design value of peak flow in each subbasin at the specified recurrence interval by using of Pearson-Ⅲ curves,which provided reference value for flood analysis and disaster prevention at no data area in the watershed.(5)The flood high-risk areas in jinjiang watershed are mainly located in downstream,which is in Nanan city and its surroundings,and the north parts of Dongxi watershed.