Testing of the revised universal soil loss equation for soil erosion assessment in the Ouringa River basin

The urban Oringa River basin is facing rapid degradation due to population growth and land use changes.The integration of remote sensing, GIS, and the revised universal soil loss equation provides an effective approach to monitor and to evaluate soil erosion in this region.The study aims to assess soil loss in the Ouringa River basin in Morocco using the RUSLE model, integrated with remote sensing and GIS.The RUSLE model includes several key factors that contribute to erosion, including rainfall erodibility (R), soil erodibility (K), slope length and steepness (LS), conservation practices (P), and vegetation cover (C).The results indicate that the Oringa River basin has been facing continuous soil erosion for four decades, with annual losses exceeding 200 tons per hectare initially and continuing through 1981-2022.The analysis reveals that 60-66% of the area experienced minor soil erosion, remaining below 100 tonnes per hectare.However, 20-23% of the land showed low erosion (100-200 tonnes per hectare), while 8-10% experienced moderate erosion (200-400 tonnes per hectare).A smaller proportion, 4-5%, experienced moderate erosion (400-1000 tonnes per hectare), and 2% experienced severe erosion exceeding 1000 tonnes per hectare.Effective soil management is critical to mitigate these losses and protect watersheds.Analysis of land use types revealed by NDVI-based that bare land, covering 67% of the watershed, significantly contributes to erosion despite its lower C factor.Conversely, tree-covered areas, accounting for 12%, have minimal erosion impact due to their dense vegetation.Built-up areas, covering 8%, have the highest C factor, indicating a high erosion potential.This thorough assessment aids in identifying priority areas for targeted erosion control efforts.