hydrological modeling for simulation of rainfall-runoff process in mountainous catchments

The hydrologic modeling system hec-hms is designed to simulate the precipitation-runoff processes for watershed systems. it is designed to be used in a wide range of geographic areas to solve various problems. this includes large river basin, water supply, and flood hydrology, and small urban or natural watershed runoff. in this study, hec-hms model was applied to develop the rainfall-runoff model applications in taghsimab, daremuradbeig, and tooijin catchments in hamedan, iran. the model also incorporates arc-gis extensions, hec-geohms, and arc-hydro tools for the spatial analysis of the watershed. the hydrological model results showed a proper fit between simulated, and observation hydrograph shape. clark unit hydrograph, scs unit hydrograph, and snyder unit hydrograph methods are used in the hec-hms model. nash-sutcliffe of the model was selected to compare, and determine the efficiency of these three methods. as a result, the snyder unit hydrograph method is appropriate than two other methods for hydrological modeling for the present study area.