Simulation of the rainfall–runoff relationship using an HEC-HMS hydrological model for Dabus Subbasin, Blue Nile Basin, Ethiopia

Hydrological modeling is important to provide relevant hydrologic information from limited data. In this study, Hydrologic Modeling System (HEC-HMS) was used to simulate the rainfall–runoff relationship for the Dabus subbasin of the Blue Nile Basin. Daily precipitation and stream flow data from 2002 to 2019 were used as key input data for the model, together with soil and land use/land cover data, and a digital elevation model of the study area. Arc-GIS was employed in combination with Arc Hydro and HEC-GeoHMS tools for terrain processing and translating spatial information into model files for HEC-HMS, respectively. Model calibration was done with data from 2002 to 2014, while the validation was done from 2015 to 2019. Nash-Sutcliffe simulation efficiency (NSE), observation standardized ratio (RSR), and coefficient of correlation (R2) were used to assess the performance of the model. With NSE, RSR, and R2 values of 0.784, 0.334, and 0.816 for calibration, and 0.793, 0.323, and 0.875 for validation, the model simulation of stream flows was found in good agreement with the observed values. Therefore, the HEC-HMS model can be utilized to predict stream flows in ungauged catchments in the Dabus subbasin from measured rainfall data for proper water resource planning and management.