Abstract: The objective in this study was to assess future water availability in the upper part of the Baro basin in Southwest Ethiopia through the Representative Concentration Pathway (RCP 4.5) scenario. HBV-96 rainfall-runoff model was calibrated and validated for historical records of streamflow. The estimated NSE and RVE values are 0.91 and -6.76% during calibration period (1996-2002) and validation period (2003-2005) values are 0.72 and 9.78% respectively. Dynamically downscaled climate model outputs were obtained from four models through the CORDEX-Africa program. The four climate models were evaluated using a suite of statistical measures such as bias, Root Mean Squared Error (RMSE) and Coefficient of Variation (CV). The bias of the simulated rainfall varies between -4.20% and -25.39% suggesting underestimation. In terms of bias, EC-Earth performs best while HadGEM2-ES performs worst. In terms of RMSE, MPI-ESM-LR performs worst while CM5A-MR performs best. All the four GCMs projections showed that the maximum temperature will likely increase by 2.08°C (MPI-ESM-LR) to 2.52°C (CM5A-MR) and minimum temperature will also likely increase by 1.65°C (EC-Earth) to 2.78°C (HadGM2-ES) in the Baro basin in medium-term (2041-2070) for the RCP4.5 scenario. However, the annual rainfall amount will likely decrease by 7.34% (CM5A-MR) to 17.42% (HaDGEM2-ES) and with a likely increase in annual potential evapotranspiration. The maximum streamflow reduction was projected for the rainy season (Kiremt) by up to 28.36% (CM5A-MR). The annual streamflow is projected to decline by up to 35.2% during 2050s. The findings of this study indicate that climate change under the RCP4.5 scenario will have a significant implication to water availability in the Baro basin.Abstract: The objective in this study was to assess future water availability in the upper part of the Baro basin in Southwest Ethiopia through the Representative Concentration Pathway (RCP 4.5) scenario. HBV-96 rainfall-runoff model was calibrated and validated for historical records of streamflow. The estimated NSE and RVE values are 0.91 and -6.76% during...Show More
