LAUSR

Abstract Sedimentation of dams and soil erosion remain a worldwide issue, this is especially true in countries characterized by great environmental diversity where their assessment remains a serious difficult issue. Morocco ranks among countries with the greatest achievements in the dams field in Africa, characterized by a great climate, vegetation cover and morphological diversity. The objective of this study was to identify the spatial distribution of Sediment Yield (SY) and Area-Specific Sediment Yield (SSY) on the country scale and to present a new simple approach by exploiting the statistical tool to assess their controlling factors. We collected and analyzed environmental data of 42 catchments of the biggest and most important dams of the country of Morocco. The adopted statistical methodology reveals that Moroccan catchments can be subdivided into 5 categories (depending on climate, morphology and vegetation cover conditions) in which SY is most related to the catchment area and drainage network length, while SSY is mostly related to the soil organic carbon stock, rainfall and clay fraction. Our approach provides important new insights regarding modelling catchment scale sediments dynamic to asses SY and SSY in different regions around the world, especially in large scale and where there is a great environmental diversity.