Spatial and Temporal Water Demand Variabilities in the Awash Basin, Ethiopia

Abstract Awash River is one of the exhaustively utilized and economically viable basin in Ethiopia. The river basin is classified into six planning areas namely Upper Awash, Halidhege, Awash Awash, Adaytu, Terminal and Eastern parts. This study investigates the spatial and temporal variability of available water in the River Basin using the WEAP model. Future scenarios are based on pre-determined government plans, utilizing climate data from 1977 to 2020 and discharge from 1999 to 2020. The focus is on six planning areas within the Awash River Basin. Results reveal a severe water shortage in the Upper Awash planning area, a vibrant economic hub in the country. While the proposed Dam at Melka Kunture may mitigate the gap by 2030, additional water supply options are needed to address projected gaps of -236.7 MCM in 2030 and − 712 MCM in 2080. The possible mitigation plan includes water storage infrastructures such as constructing reservoirs, implementing water harvesting structures, and utilizing groundwater resources. While the Halidhege planning area requires special attention, lacking proposed dams or studied water supply options. Water gaps are projected to be -53 MCM in 2050 and − 761.2 MCM in 2080. Potential solutions involve small-scale water harvesting, reservoir construction, and groundwater utilization. The Eastern Planning area, covering the largest portion of the Awash Basin, faces water shortages throughout the study periods. Minimal rainfall and elevated temperatures exacerbate the strain on limited water resources. Projected water gaps are − 112.1 MCM, -79.4 MCM, and − 297.6 MCM in 2030, 2050, and 2080, respectively. The study emphasizes the importance of additional water supply options, such as immediate water harvesting structures, long-term reservoirs, and appropriate groundwater utilization, to bridge the projected water gaps and ensure sustainable development in the Basin.