Quantifying soil erosion rate in Kampe Omi Dam Basin, Nigeria, through integrated geospatial and RUSLE modelling

Abstract

Abstract Soil erosion remains a critical driver of land degradation in Nigeria and threatens agricultural productivity, water resources, and ecological stability. This study quantified soil erosion in the Kampe Omi Dam Basin (KODB), Nigeria, using the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information Systems (GIS). The model factors, namely rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C), and support practices (P), were derived from multi-source satellite data, digital elevation models, field soil surveys, and rainfall records. The results revealed that the actual annual soil loss across the basin ranged from 0.00 to 4,458.65 t/ha/yr, with a mean of 18.09 t/ha/yr. A total of 53.41% of the catchment fell within a very low erosion risk (0–5 t/ha/yr), and very high and extremely high classes (8.39%) contributed 66.43% of the estimated gross soil loss, concentrated in steeply sloping cultivated lands of the southern and southeastern uplands. A comparison of potential and actual soil loss revealed the protective role of vegetation cover and land management, but also showed the limited effectiveness of existing conservation practices in erosion-prone zones. This study established a spatially explicit baseline for erosion risk in the KODB, providing critical insights for prioritising soil and water conservation measures. Targeted interventions, including vegetation restoration, contour farming, and structural erosion control, are recommended to mitigate soil degradation, safeguard agricultural productivity, and preserve reservoir sustainability.