Hydrologic responses contemplating to Land use Land cover change and water balance of Lake Chamo sub-basin of Ethiopia

Land use and Land cover (LULC) change is one of the main driving forces of environmental change that can potentially alter the hydrological response of an area. Lake Chamo sub-basin is subjected to severe erosion as a result of climate change and sedimentation, which further exacerbates the amount due to land use and land cover changes. However, less research attention had been given to evaluate the effect of LULC on the propagation of lake water balance. Therefore, in this study, the hydrological responses to changes in LULC as well as the Lake Chamo water balance were evaluated using physically distributed hydrological model, Soil Water Assessment Tool (SWAT). Four (4) periods of LULC datasets, namely 1990, 2000, 2010 and 2021, were used to analyze the effects of LULC change on the water balance of the sub-basin. The simulation result indicates that 2.6% and 2.1% of forest converted to agricultural land and built-up area, respectively; 18.3% and 14.3% of shrub land converted to agricultural land and built-up area, respectively between 1990 and 2021. The findings of Lake Chamo water balance analysis revealed total inflow of 392 million cubic meters per year (MCM year⁻¹), outflow of 366 MCM year⁻¹, and the change in storage of 25.4 MCM year⁻¹. Results have shown that the surface runoff increases from 4.6 to 72.5 mm as well as sediment load rose from 0.26 to 4.21 t/ha due to LULC changes, mainly expanding to urbanization and intensive agriculture. This study suggests the LULC is crucial for integrated water resources management in the study area.