Impact of infiltration methods on the accuracy of rainfall-runoff simulation

Abstract

In this research, attempts are maid to evaluate the performance of HEC-HMS (Hydrological modeling) in simulating the rainfall-runoff using two different rainfall infiltration methods. The rainfall-runoff process for the study area which consist of two catchments namely kenyir catchment and Berang catchment, Terengganu, Malaysia is simulated using HEC-HMS program. Two methods for estimating infiltration (rainfall abstraction losses) are built in the program. These methods are SCS Curve Number method and Green and Ampt method. The impact of selected method on the accuracy of rainfall-runoff simulation is studied. Statistical analysis include the computation of the coefficient of determination (R 2), the mean square error (MSE) and the Mean Absolute Percentage Error (MAPE) were used to check the accuracy of HEC-HMS simulations using the two infiltration methods. The result showed that the errors in the simulation output using the SCS Curve Number method were 6.5% for Berang catchment and 8.2% for Kenyir catchment, while the errors in the simulation output using Green and Ampt method were 9.13% for Berang catchment and 11.11% for Kenyir catchment. As a conclusion, it is found that the output of HEC-HMS program is in agreement with the historical recorded data and it is recommended to use the SCS Curve Number infiltration method for the tropical catchment due to its low error in simulation output. © Maxwell Scientific Organization, 2012.