Estimating Sediment Yield and Soil Loss for Conservation Prioritization: Implications for Natural Resource Management in the Boricha Sub-Catchment, Rift Valley River Basin, Ethiopia

Abstract Soil erosion continues to threaten the sustainability of farming activities in Ethiopia’s highland areas, where steep slopes and variable rainfall persistently impact productivity and environmental health. Focusing on Boricha Sub-Catchment in the Rift Valley Basin, the study examined patterns of soil loss and sediment yield using the RUSLE model and 2022 GIS-based spatial inputs. Key input parameters included rainfall, elevation, soil type, and land cover. Estimated annual soil loss ranged from 0 to 359.76 t/ha/yr, with an average of 31.63 t/ha/yr, well above Ethiopia’s tolerable soil loss threshold. Sediment yield across the catchment varied between 0 and 80.7 t/ha/yr, averaging 2.01 t/ha/yr. The sediment delivery ratio was calculated as 0.2234. Northern and central zones were identified as erosion hotspots, particularly in sub-watersheds SW1, SW10, and SW9. In contrast, SW3, SW4, and SW7 showed minimal erosion activity. These findings support a prioritization framework for soil conservation, offering evidence-based recommendations such as reforestation, terracing, and check dam construction. The study confirms the value of GIS-integrated RUSLE modeling as a practical tool for decision-making in watershed protection.