Performance of Semi-Distributed Hydrological Models in Stream Flow Simulation

Abstract

Hydrological measurements are vital for Water Resources Planning and Management. Modeling rainfall-runoff may be used to understand the impact of future hydrological changes such as flooding, soil loss, and sedimentation effect on lakes and reservoirs for irrigation and hydropower. But the difficult one is the selection of the best models. All hydrological models may not be equally performed due to being influenced by input data and over models system that will be used for the analysis. Therefore, two hydrological models; Soil and Water Assessment Tool (SWAT), and Hydrologic Engineering Centers Hydrological Modeling System (HEC-HMS) models to simulate rainfall runoff. These models were calibrated and validated using daily observed streamflow data. The R2 and NSE were used to check the performance of the models and the result indicates that during HEC-HMS model calibration and validation, R2 of 0.6 and 0.61, NSE of 0.55 and 0.53, generated respectively. During the SWAT model accuracy assessment, the values of model performance indicators were R2 of 0.69 and 0.68, NSE of 0.58 and 0.52 for calibration and validation respectively. This indicates both SWAT and HEC-HMS models have been satisfied in streamflow simulations. The SWAT model overestimated the daily streamflow more than the observed and HEC-HMS simulated streamflow. These models overestimated peak streamflow during both the calibration and validation period. The curve number grid generated by HEC-GeoHMS was slightly lower than the curve number simulated by the SWAT model.