Evaluation of SCS and Geomorphologic Instantaneuos Unit Hydrograph (GIUH) in Jooneghan basin

Watershed flood hydrograph derivation is one of the most important hydrologic for hydraulic structures design. One of the most widely used experimental models in this context, is the SCS dimensionless unit hydrograph. Also the Geomorphologic Instantaneous Unit Hydrograph (GIUH) model presented by Rodrigoes-Iturb etal. (1979). Simulates the watershed rainfall runoff process based on quantitive geomorphologic parameters and design rain. In this study the performance of above mention methods wasn investigated over one of the Karoon river sub basin so called Jooneghan basin located in Chaharmahal and Bakhtiari province. Geomorphologic parameters were computed by preparing DEM maps and after simulation, the relative performances of the models were compared. The RME in peak flow calculated by GIUH model, was (11%) while the RME residuat mean squane error in SCS method was (22%). The results also revealed that the GIUH model has performed better than SCS model in estimating flood peakato and time b peak.