ASSESSING AND MAPPING IRRIGATION POTENTIAL IN THE ABBAY RIVER BASIN, ETHIOPIA

Population growth and increasing food demand coupled with frequent droughts and famine have brought Ethiopia's agricultural growth to a crossroads. The Abbay River basin has untapped potential for irrigation and hydropower development. Numerous models and studies have suggested various irrigation schemes but have failed to precisely identify the irrigation potential or the cropping patterns and water withdrawal requirements of the basin. Investing in irrigation could provide a solution to meet the growing demands for food and development in Ethiopia. Using Mike Hydro model, our research goal was to map and assess the potential irrigation areas and water requirements for the entire Abbay River basin. Ethiopia's total potential irrigation area is estimated to be 7.5 million hectares (ha), and our study estimated that the potential irrigation area in the Abbay River basin is 738 183 ha, which is higher than that of the Abbay Master Plan estimation of 526,000 ha. The average irrigation efficiency in the basin was calculated to be 50%, and the cropping pattern ranged from 1 to 7 crops per year, and we found that maize, cotton, and sugarcane covered the highest proportions of the irrigation areas (22%, 16%, and 13%, respectively). We categorized the regions within the basin into six irrigation schemes and found that nearly all irrigation schemes required more water between December and March. The Megech, Beles, Abbay at Kessie, and Tis Abbay regions required notably more irrigation water than the others, and we estimated the total Abbay basin’s annual irrigation water requirement is 9 Billion Cubic Meters (BCM). Accordingly, our research suggests that the annual irrigation water requirement will increase significantly in the future. Thus, given the anticipated seasonal and interannual water flow variability due to climate change, our study suggests that more storage dams should be constructed to control water variability and satisfy irrigation water requirements in the basin