Geospatial assessment of erosion intensity and prioritization of vulnerable areas in the Shafe catchment, South Ethiopian rift Valley

Abstract Soil erosion remains a persistent environmental challenge threatening the livelihoods of rural households in the Shafe catchment, located within the Abaya-Chamo sub-basin of South Ethiopian Rift Valley Lake basin. This study aimed to estimate the spatial extent of soil loss and to identify erosion-prone areas for targeted and effective intervention measures. A combined approach utilizing the Revised Universal Soil Loss Equation (RUSLE) and Geographic Information System (GIS) was employed, incorporating six key factors: rainfall erosivity (R), soil erodibility (K), slope length (L), slope steepness (S), cover-management (C), and support/conservation practices (P). The results revealed that the annual soil loss in the Shafe catchment ranged from 0.203 t ha −1 yr −1 to 87.38 t ha −1 yr −1 , with a mean soil loss rate of 3.308 t ha −1 yr −1 . The highest rate of erosion was recorded on cultivated land (87.38 t ha −1 yr −1 ), making it the most erosion-susceptible land use type in the area. The total estimated annual soil loss from the catchment was 57,567.83 tons, with cultivated and bare lands contributing approximately 43.05% of this total. The study also highlighted considerable spatial variability in soil loss across different land use/land cover types, slope classes, and site-specific conditions. These findings underscore the urgent need for implementing integrated soil and water conservation measures, particularly on steep farmlands and bare lands, to rehabilitate the degraded landscape and enhance sustainable land management in the catchment.