Capability Assessment of GIUH Method for Predicting the Dimension of Instantaneous Unit Hydrograph and Compare it with Snyder, SCS and Triangular Methods

One of the most important objectives in hydrological studies is quantitative rainfall-runoff process estimation at the basin. Several methods and models have been created in order to simulate the Rainfall-Runoff process that each one has its’ own advantages and disadvantages. The aim of this study is to investigate the capability of the Geomorphologic Instantaneous Unit Hydrograph model in flood hydrograph development and comparing its’ performance with Snyder, SCS and Triangular models. In order to implement the mentioned methods, Rainfall-runoff data were collected for 14 events and direct hydrograph was obtained. According to the statistical indicators such as RMSE, MRE and Nash-Sutcliff Coefficient, comparison of the observed and estimated hydrographs depicted that the GIUH method was the most efficient in peak discharge estimation, and Triangular, SCS and Snyder models were the next, respectively. Also according to the results, Snyder, GIUH, Triangular and SCS methods have the most efficiency to predict the time to peak, respectively. In addition the results indicate a low estimation for GIUH and SCS methods in peak discharge prediction and over estimation for Snyder and low estimation for GIUH method in time to peak prediction.