Impact of climate change on future availability of water for irrigation and hydropower generation in the Omo-Gibe Basin of Ethiopia

Study region: Omo-Gibe River Basin, Ethiopia Study focus: The objective of this study was to predict the impact of climate change on the future availability of water for irrigation and hydropower production. Climate change projections for the near future (2017-2044), medium (2045-2072), and long-term (2073-2100) using a multi-model set average of fifteen regional climate models under the RCP4.5 and RCP8.5 emission scenarios. Water availability, allocation, and demand for irrigation and hydropower generation were pre-dicted using the coupled Soil and Water Assessment Tool (SWAT) and Water Evaluation and Planning (WEAP) hydrological models. New hydrological insights for the region: The projected annual average temperature increase range is 2.10-3.6 C under RCP 4.5 emission scenarios while 2.7-4.8 C under RCP 8.5. Under RCP 4.5 and RCP 8.5 emissions scenarios, projected annual average precipitation declines ranged from 10.7-13.6 % and 11.1-13.8 %, respectively. Projected annual average declines in streamflow ranged from 7.0 % to 10.9 % under PCR 4.5 emissions scenarios, while 10.9-2.8 % under PCR 8.5. As a consequence, water shortages for irrigation may decrease by 15.5-25.4 % and hydroelec-tricity by 10.5-20.2 % during study periods. Due to the combined effect of climate change and rising water demand, the increase in water scarcity ranges from 7.9-30.6 %. The projected results showed that future water availability for irrigation and hydropower generation will decline in the future. Climate change adaptation options are needed to ensure future water availability for hydropower generation and irrigation.