Application Of The HEC-HMS Model In Semi-arid Sub-humid Areas And Parameter Calibration

More and more losses are caused to the local people and economic by mountain torrent disaster in small watershed in semi-arid and sub-humid areas,with the increase of human activities.It can effectivelyreduce the loss of disaster by simulation and forecast in a certain extent.It is relatively complex of the runoff process in semi-arid and sub-humid areas,for there are filling up runoff and infiltration runoff at the same time.Combined with such regions tend to be no or less data,so that makes it difficult with the traditional method for such areas for flood forecasting.It provides a new way to solve this problem by the emergence of hydrological models.HEC-HMS model is the latest research and development of half a distributed hydrological model by U.S.Army Crops of Engineers Hydrologic Center,the model of integration of a large amount of hydrological calculation method can do well in humid areas,arid areas and arid and semi-arid areas for simulation.This study first use the HEC-GeoHMS module to deal with the DEM data.We divided the study area into 13 subbasins after following steps such as filling,Extract the drainage,Divide the watershed.We use gage wight method in meteorologic model,and the wight of each gage calculated by Thiessen polygonThe runoff producting method in this sudy is SCS-CN,the computing method of transform is Snyder,s UH and the routing method is the lag model.We use two floods in the study area to simulate and calibrate the parameters after estimate the parameters.And the parameters calibration used artificial rate combined with model automatic optimization method.We test the parameters using another flood in the study area.The error of the volume at the Basin export is 3.4%,The error of the peak discharge is 19.7%,the error of the time of peak discharge is 1 hour.Simulation results conform to the relevant regulations in hydrology information forecast specification(SD 138-85).So the HEC-HMS model can do well in the simulation in semi-arid and sub-humid areas and it is value to generalize it.It has reference value for the further study that the parameters we achieve in this sudy.