Evaluating the HEC-HMS Hydrologic Model in Order to Simulating Flood Hydrograph in Forest Basin (Case Study: Kheyrud Forest)

Soil Conservation Service Curve Number method (SCS-CN) is a widely applied technique for predicting direct runoff from rainfall has been used around the world. In this study, the curve number maps and entry physical model data of Kheyrud basin to HEC-HMS model, the HEC-GEOHMS extension in ArcGIS software and Google Earth satellite images were used. In addition to the statistical analysis of survey data of maximum daily rainfall in rainfall stations, and entry the basin meteorological model into HEC-HMS, the SPSS, Excel, Easy Fit, and Curve Expert were used. Flood hydrograph in 2, 5, 10, 25, 50 and 100 years return periods have been simulated. Finally, in order to model calibration, after a review of hydrometric data of Kheyrud station, three events corresponding to the calibration and validation, two events were used for model calibration and one event was used for validation. The results of the peak flow output from each sub basin showed that A1 sud basin with a maximum peak flow was located in the first place of floodness and the B2 sub basin are ranked in the last place of floodness due to the minimum size compared to the other sub basins. Result showed that the performance of the calibrated HEC-HMS model to simulate the flood peak flow has been approved in the studied area.