Résumé
In North Africa, the filling of dams by sediments is a major problem. Relationships with the evolution of land use and climate change are poorly understood. The hypothesis is that changes in land use and increasing agricultural pressure, associated with a sustained decrease in rainfall, fragilize soils and make them more susceptible to erosion. Two major watersheds are studied in the framework of SIGMED (spatial approach of the impact of agricultural activities on sediment transport and water resources in large catchments): Wadi Bouregreg in Morocco and Wadi Mina in Algeria. One of the objectives is to follow the evolution of land-cover to identify sensitive areas and compare with sedimentation in dams. Erosion from the immediate banks of the dams could be a major source of sediment in reservoirs and be the focus area for operations of protection and restoration of vegetation, preventing the risk of filling.