ABSTRACT Precise streamflow prediction is fundamental for effective water resources management, flood risk mitigation, and sustainable agricultural planning, particularly in regions dependent on rainfed agriculture. This study evaluates the prediction capability of four hydrological models of parameter-efficient distribution (PED), Hydrologiska Byråns Vattenbalansavdelning (HBV), Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS), and Soil and Water Assessment Tool (SWAT) in the Koga Watershed, Ethiopia. The models were calibrated from 1997 to 2006 and validated from 2007 to 2011 using observed daily streamflow. During calibration, the PED model showed the best performance with coefficient of determination (R2) (0.79), Nash–Sutcliffe efficiency (NSE) (0.782), root mean square error (RMSE) (0.42), and percentage of bias (PBIAS) (7.56%), while SWAT simulated the highest flows, and HEC-HMS slightly overestimated flows. During validation, PED had an excellent performance (R2 = 0.70, NSE = 0.72, RMSE = 0.65, and PBIAS = 16%), whereas HBV had minimum flows, and SWAT forecasted minimal flows. Inclusively, the PED model is found to be the most suitable model for flow prediction in the watershed established due to its consistency for sustainable water resource management. The findings provide valuable insights for selecting suitable hydrological models to improve water resource planning and execution.
Wubu et al. (2026) studied this question.