<p>Soil erosion and sedimentation, intensified by climate change, pose significant ecological and socioeconomic challenges globally. This study investigates the hydrological and ecological impacts of sedimentation in Ethiopia’s Burji-Kelale Sediment-Dammed Lake, formed at the confluence of the Haro, Upper Segen, and Turkute Rivers. The lake’s formation and ongoing degradation are closely linked to severe soil erosion driven by deforestation, unsustainable agriculture, and vegetation loss in the surrounding watershed. The primary objective is to quantify long-term soil erosion rates and assess their impact on lake sustainability and agricultural productivity. Using the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information Systems (GIS) and remote sensing, the study analyzes soil erosion patterns from 2002 to 2023. Results indicate an average annual soil loss of 8.2 t ha⁻¹ yr⁻¹, with maximum losses reaching 1694 t ha⁻¹ yr⁻¹. The watershed experiences an estimated total soil loss of approximately 3.06&#xa0;million tons annually. A notable sedimentation event occurred in 2012/13, when accelerated erosion led to excessive deposition, obstructing river flow and forming the sediment-dammed lake. The findings underscore a rising trend in erosion, correlating with expanding cultivation and diminishing vegetation cover. To address these challenges, the study recommends erosion control strategies such as interconnected pond systems, large-scale reforestation, and integrating modern and Indigenous land management practices. These approaches are essential to enhance ecosystem resilience and ensure the long-term sustainability of the Burji-Kelale Sediment-Dammed Lake and its surrounding watershed.</p>