<p>Water erosion is a major environmental issue in semi-arid Mediterranean basins, where intense rainfall, steep terrain, and sparse vegetation accelerate soil degradation. In Morocco, quantitative erosion assessments remain limited for several small and medium watersheds, constraining effective mitigation. This study estimates average annual soil loss in the Lahouar watershed using two empirical approaches, the Revised Universal Soil Loss Equation (RUSLE) and the Erosion Potential Method (EPM), implemented within a GIS and remote sensing framework. RUSLE predicts a mean soil loss of 2.52 t ha⁻¹&#xa0;yr⁻¹ (range: 0–58.8 t ha⁻¹&#xa0;yr⁻¹), whereas EPM yields a substantially higher mean of 25.78 t ha⁻¹&#xa0;yr⁻¹ (range: 0.9–84.4 t ha⁻¹&#xa0;yr⁻¹), i.e., about ten times the RUSLE estimate. According to EPM, 19% of the basin exceeds 50 t ha⁻¹&#xa0;yr⁻¹, indicating pronounced erosion hotspots. The contrast between the two model outputs highlights the sensitivity of erosion estimates to methodological choice and input parameterization. Overall, the results provide quantitative support for prioritizing erosion-prone zones and guiding targeted soil and water conservation measures in the Lahouar Basin.</p>