Hydrological responses projection to the potential impact of climate change under CMIP6 models scenarios in Omo River Basin, Ethiopia

Climate change has a negative impact on the basin's hydrological processes and water resources. In this study, the projected impacts of climate change on hydrological processes in the Omo River Basin was evaluated under two Shared Socioeconomic Pathways (SSP245 and SSP585) scenarios. The latest Coupled Model Inter-comparison Project (CMIP6) climate model dataset of precipitation and temperature were used to assess the anticipated climate impact in the basin. The SWAT model was used to simulate the effects of climate change throughout the baseline (1990–2019), near (2031–2060), and far future (2071–2100) periods. The basin's predicted stream flow will increase annually and monthly in June, July, August, and September (JJAS) under both scenarios except decrease in the months of March, April, and May (MAM) under the SSP245 scenario. The basin mean annual and seasonal (JJAS and MAM) surface runoff will increase under the SSP585 scenarios; however, it decreases under the SSP245 scenario. The basin's mean annual and seasonal groundwater will increase in the near and far future under both scenarios except decline in MAM under SSP245 scenario. Likewise, the water yield will decrease in MAM under the SSP245 scenario, nevertheless, increases in annual and seasonal under both scenarios. The potential evapotranspiration increases with temperature over the basin in all circumstances. There will be significant spatial variations in the basin's water balance components in the future. The results of this study will be essential for managing water resources in the future, creating plans for coping with climate change, and reducing the basin's risk of flooding and water scarcity.