Assessment of the effects of climate change on water balance components in the upper Erer subbasin, Ethiopia

Abstract

Eastern Ethiopia watersheds are located in transition zone from Arid to semi-humid climate and in expanding to westwards the west annual rainfall is highly declining. This paper explains future hydrological response impacts under changing climate using ensemble average of the CORDEX RCMs for historical (1979–2014) and future (2024–2070) periods. The result revels the monthly average temperature varies (0.04–6.25°C) for RCP-4.5, while it varies (0.03–6.59°oC) for RCP-8.5. The monthly average rainfall to be decline by 90.71 mm and rise by 211. 22 mm for RCP-4.5, while it is going to decline by 84.97 mm and rise by 235.62 mm for RCP-8.5. The adjusted SWAT model was used to detect the changes of projected hydrological response from reference period. Balance components of the baseline period was compared to future period. The result shows the change in decrease of annual mean surface flow (4.98 %–5.63 %), groundwater flow (5.63 %–6.68 %), evapotranspiration (2.45 %–2.57 %) and water yield (5.54 %–5.21 %) to be expected from RCP-4.5 to RCP-8.5. The findings of this paper provide valuable assistance to water resource planners by enhancing their comprehension of change in climate effects at local level.