Assessment of Erosion Risk and Sustainable Mitigation Strategies: A Case Study of Agoudal Watershed (High-Atlas, Morocco)

Abstract

The Agoudal watershed, situated in the region of Draa-Tafilalet, the province of Midelt in southeastern Morocco, is the upstream part of the Imilchil valley. These delicate habitats, which span the central great Atlas altitudinal range from 2400 to more than 3150 m, are under great risk of erosion because of their poorly protected and unarable soils. Climate change, biological issues, and anthropogenic activities have all contributed to the region's extensive deterioration. This study uses the RUSLE approach in conjunction with GIS and remote sensing to evaluate erosive processes in the Agoudal sub-watershed and identify priority susceptible areas. An inventory of the study area is conducted to target hot spot areas, establishing a development map as the basis for implementing sustainable mechanical and biological mitigation measures. The results demonstrate reliable simulation of water erosion dynamics by the RUSLE model. Almost the entire basin faces severe soil degradation, with approximately 66% falling into specific degradation classes of 50 to 400 tons per hectare per year, and 18.9% displaying low to medium rates ranging from 7.4 to 32.17 tons per hectare per year. Only 1.4% of the watershed experiences degradation rates below 7.4 tons per hectare per year. The average soil loss rate is 255 tons per hectare per year, with a standard deviation of around 285 tons per hectare per year, reflecting the environment's heterogeneity. These figures attest to the high erosion risks in the region, compounded by recurrent floods, endangering food agriculture. Urgent mitigation intervention is necessary to address this alarming situation and protect the area's agricultural productivity.