Response of climate change impact on streamflow: the case of the Upper Awash sub-basin, Ethiopia

Abstract

This paper discusses the response of climate change impact on future streamflow availability in Upper Awash River basin, Ethiopia. The change of climate was built using the CORDEX, RCM daily precipitation, maximum and minimum temperature under RCP4.5 and 8.5 scenarios. The climate model was examined in the historical period 1996–2015 for its ability to capture observed precipitation and temperature. Bias correction was performed on RCM temperature and precipitation to minimize the uncertainties that may occur from climate model projection. After the successful calibration and validation of the HBV hydrological model, streamflow was simulated for the periods of 2021–2040 and 2041–2060 and compared to streamflow of the baseline period 1996–2015 to investigate the changes. The results suggested that overall, following the precipitation increment, streamflow is expected to increase under both RCPs. The average monthly changes of streamflow are expected to increase by 40.1 and 29.4% under RCP4.5 and 16.9 and 18.5% under RCP8.5 scenarios for 2021–2040 and 2041–2060, respectively. Annual streamflow would increase by 28.5 and 23.95% under RCP4.5 and 8.5, respectively. The results of this work can help and inform the water resources planner and designer to frame an appropriate plan and management for the effective use of water in the future. HIGHLIGHTS This study focus on stream-flow response to projected climate change in the Upper Awash sub-basin, Ethiopia.; This paper coupled RCM with RCPs and HBV hydrological model.; Bias correction was performed on RCM temperature and precipitation.; Comparative analysis of the differences between projected and baseline stream-flow were discussed.; Overall projected stream-flow would increase under both RCP scenarios.;

Keywords

• bias-correction
• climate change
• climate model
• climate scenarios
• streamflow