Modelling historical and future land use and land cover change impacts on hydrology in Yadot Watershed, Genale Dawa Basin, Ethiopia

Abstract Land use and land cover change (LULCC) is a primary driver of environmental change, significantly affecting watershed hydrological processes. This study examines the effects of LULCC on hydrological parameters in the Yadot watershed of the Genale Dawa Basin. To analyse both historical and future LULC change projections, the study employed ERDAS Imagine 2014 software and the SWAT model. This research used the Cellular Automata-Markov model within IDRISI software to predict future LULC changes. Using Landsat images from 1985, 2000, and 2015, along with predicted future LULC changes for 2035 and 2055, six LULC classes (forestland, woodland, scrubland, agricultural land, grassland, and settlements) were developed. The results revealed a 132.8% (59.6 km²) expansion of agricultural land and a 511.9% (4.5 km²) increase in settlement area, accompanied by a 6.19% (29.8 km²) decline in forest cover and a 4.08% (2.3 km²) reduction in scrub/bush land between 1985 and 2015. Over the same period, grassland and woodland also experienced a decline by 3.21% (1.8 km²) and 31.01% (30.3 km²); respectively although a gradual increase is projected between 2015 and 2035. The analysis indicated that surface runoff and water yield have historically increased by 2.95% (4.81 mm) and 0.88% (3.58 mm) due to LULCC, with a similar trend expected in the future. In contrast, lateral flow and groundwater flow show occasional decrease of 4.84% (3.49 mm) and 2.18% (3.60 mm), respectively. By analysing both historical changes and projecting future impacts up to 2055, this research provides a comprehensive, long-term perspective on how continued LULC dynamics will alter key hydrological processes in the watershed. The study highlights potential implications for comparable watersheds and underscores the importance of effective LULC-based management strategies such as sustainable land use planning, ground water recharge enhancement, and soil conservation for flood prevention, risk mitigation, and broader climate change adaptation.