Integrating RUSLE, GIS, and Remote Sensing for Soil Erosion Assessment in Morocco's Raouz Watershed

¹ EMRN, FSTT, Abdelmalek Essaadi University. Tangier, Morocco
² Applied Geosciences Research & Development Laboratory, Abdelmalek Essaadi University, Tétouan

^* Lhoussaine Ed-daoudy: leddaoudy@uae.ac.ma

Abstract

Soil erosion threatens sustainable development in Morocco's Rif Mountains, causing severe land degradation and reservoir sedimentation. This study quantifies erosion rates in the Raouz watershed (46.89 km²) using the Revised Universal Soil Loss Equation (RUSLE) integrated with GIS and remote sensing. We analyzed five erosion factors: rainfall erosivity (R), soil erodibility (K), topography (LS), cover management (C), and conservation practices (P). Results reveal a mean annual soil loss of 16.53 t ha^-1 yr^-1, with severe erosion (>20 t ha^-1 yr^-1) affecting 26.4% of the watershed. Critical hotspots (7.3% of area) contribute 35-40% of total sediment yield. Validation against Caesium-137 measurements shows strong agreement (R²=0.76). Topography (52% variance) and vegetation cover (31% variance) emerge as dominant erosion controls. The Moulay El Hassan Ben Mehdi Dam faces annual sedimentation of 23-31 t yr^-1, threatening water security for 500,000 inhabitants. Findings support targeted conservation strategies prioritizing steep, sparsely vegetated upper watershed areas.