Comparison of HEC-HMS hydrologic model for estimation of runoff computation techniques as a design input: case of Middle Awash multi-purpose dam, Ethiopia

Abstract Rainfall-runoff modeling requires a selection of a suitable hydrologic model for the determination of an accurate quantity from a given process. For this study, the HEC-HMS event-based hydrologic model of the Initial and constant, the Green and Ampt, and the SCS CN loss methods were selected as a modeling tool for estimation of the amount of runoff at the middle awash multi-purpose dam on the Awash River basin. The HEC-HMS model calibration of this study was done by using the meteorological and hydrological data for the years from 2004 to 2008. The model was validated by using the daily data for the years from 2009 to 2013. The results with the comparison of the observed and simulated hydrographs and the model performance showed that the initial and constant (Nash-Sutcliff NSE = 0.73, Correlation coefficientR2 = 0.75, and RMSE = 0.5) model is appropriate for hydrological simulations in the Middle Awash Catchment.