Soil erosion and sediment transfer represent major environmental challenges in semi-arid regions of southern Morocco, particularly in large watersheds characterized by strong topographic contrasts and fragile environmental conditions. This study assesses soil loss, sediment delivery, and channel sediment yield in the High and Middle Drâa watershed using a GIS-based implementation of the Revised Universal Soil Loss Equation (RUSLE) combined with sediment delivery ratio (SDR) analysis. Climatic data, land use and land cover information, soil properties, and a 30 m resolution digital elevation model were processed within the ArcGIS environment to derive the spatial distribution of erosion-related factors and quantify sediment dynamics. The results reveal a marked spatial heterogeneity of soil erosion intensity across the watershed. Very slight and slight erosion classes dominate in terms of area, covering about 61.7% of the basin, but contribute less than 4% of the total soil loss. In contrast, very high and extreme erosion classes together account for approximately 22.2% of the watershed area while generating more than 81% of the total annual soil loss. The estimated total soil loss reaches about 6 366 005 tons per year, with an average soil loss rate of approximately 46.2 t ha⁻¹ yr⁻¹. Sediment delivery analysis indicates an average SDR value of about 0.17, highlighting a limited efficiency of sediment transfer from hillslopes to the drainage network. Channel sediment yield ranges from less than 5 to more than 20 t ha⁻¹ yr⁻¹, with severe sediment yield classes representing only 21.7% of the channel surface but contributing over 70% of the total sediment delivered, estimated at approximately 1.09 million tons per year. The scientific contribution of this study is the quantitative identification of a spatial and functional decoupling between soil erosion intensity and sediment export , with sediment dynamics primarily controlled by slope, drainage connectivity, and land cover.