Evaluating the Methods of Flood Hydrograph Simulation Using HEC-HMS Model, A Case Study: Shapoor River, Iran

Runoff hydrograph widths represent the basin's reaction to rainfall. The purpose of this research is evaluating methods of SCS, Snyder and Clark in simulation of flood hydrograph by using HEC-HMS model. For this purpose 0 rainfalls - runoff events were extracted from Tange Chogan and Booshigan hydrometric stations in the Shapoor River Basin. The model parameters were calibrated based on seven observed events. Another three events were used for model verification.Comparing the simulation results showed that the ability of different methods varies in different basins. On the other side a given method estimates flood hydrograph characteristics with different accuracy. Therefore the purpose of simulation should be considered in selecting of model. According to the evaluation indices it can be concluded that in total the Clark method estimated the peak flow, flood volume and time to peak flow more accurate than the other two methods. The mean relative error values of the Clark method were calculated 9.67, .23 and 4.23 percent for peak flow, flood volume, time to peak flow respectively, in the Tange Chogan station. The corresponding values for the Booshigan station were 5.0 , 5.97 and 6.89 percentt.