Hydrological impacts of past and future land use land cover changes in the Upper Omo Gibe Basin, Ethiopia

ABSTRACT This study investigates the impacts of historical and projected land use land cover (LULC) changes on hydrological processes in the Upper Omo Gibe Basin, Ethiopia. LULC maps for 1988, 2005, and 2022, along with future projections for 2039 and 2056, were used to assess spatiotemporal dynamics and hydrological responses. Historical LULC was derived from Landsat imagery, while future LULC was projected using a cellular automata artificial neural network (CA-ANN) implemented in the Modules for Land Use Change Evaluation (MOLUSCE). Results indicate substantial expansion of agricultural land from 52.03 to 74.14%, along with increases in built-up areas (2.33–9.11%) and water bodies (0.05–2.05%) between 1988 and 2056, accompanied by a sharp decline in forest cover from 29.86 to 6.14%. Surface runoff is projected to increase from 368.46 to 512.42 mm, while evapotranspiration decreases from 567.80 to 544.50 mm. Lateral flow and groundwater recharge decline markedly, from 81.96 to 62.36 mm and 365.04 to 264.29 mm, respectively. Total water yield shows a slight increase, driven mainly by enhanced surface runoff. These findings underscore the need for sustainable land and water management strategies in the basin.