Evaluating the methods of Flood Hydrograph Simulation using HEC-HMS Software (A Case study, Chelgazi Watershed)

Rainfall-runoff models are one of the best models for flood hydrograph simulation and flood management, especially in regions with no flood data. In this study, the capability of HEC-HMS model was investigated and the magnitude of peak flood, time to peak and runoff volume parameters were compared by the Snyder, Clark and SCS methods for flood simulation in Chelgazi basin. For this purpose, seven rainfall events were selected. The model parameters were calibrated based on five observed events. Another two events were used for model verification. Then the model capability was used to estimate runoff through comparison with real data. The simulated and observed hydrographs were compared using R2 and RMSE statistics. The results showed that the SCS method is more appropriate than Clark and Snyder methods. The RMSE values of simulated and observed peak flow were 1.1, 1.4, and 1.5 for SCS, Clark and Snyder models, respectively.