Alireza Samavati - Master of Hydraulic Structures, Faculty of Engineering, Bu Ali Sina University, Hamedan, Iran.
Majid Fazli - Assistant Professor, Department of Civil Engineering, Hydraulic Structure, Faculty of Engineering, Bu Ali Sina University, Hamedan, Iran.
SayedWali Baran - Master of Hydraulic Structures, Faculty of Engineering, Bu Ali Sina University, Hamedan, Iran.

The Hydrologic Modeling System HEC-HMS۱ is designed to simulate the precipitation-runoff processes for watershed systems. It is designed to be used in awide range of geographic areas to solve various problems. This includes large river basin, water supply, and flood hydrology, and small urban or natural watershedrunoff. 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-GIS۲ 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.

HEC-HMS, GIS, Hydrological model, Water resources