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The sources of land degradation in many watersheds are runoff and erosion. In order to delay this degradation resulting in the loss of soil fertility, a system for its quantification needs to be established. Erosion severely impacts our natural capital and requires several studies and prevention and management steps. This research focuses on validating the revised universal soil loss equation (RUSLE) method through evidence from remote sensing (RS) and the Geographic Information System (GIS) in the watershed of the Inaouene river upstream of the Idriss 1st dam in the Taza region (northeast of Morocco). In this context, the approach adopted was performed, consists in combining the revised universal soil loss equation (RUSLE) to quantify erosion and GIS to spatialize the factors responsible for water erosion and soil loss (climate, soil, vegetation, and topography) GIS to produce a map of erosion risk. The results achieved show that the Inaouene watershed is characterized by an average climatic aggressiveness, a sparse vegetation cover without any safeguards, moderate to high erodible soils with a maximum ranging from 50 to 150 t/h/year. Topography characterized by high (50%) to moderately broken reliefs. The human intervention remains the most mattering factor in the embrittlement and the accentuation of the soils vulnerability for erosion for every dominant natural factor. The results of this study could be of use in prioritizing areas for soil conservation measures and watershed development and management. It is a tool for decision-makers, planners, and decision-makers in soil and water conservation decision-making to implement anti-erosion strategies to reduce the impact of erosion.

The present work focuses on the prioritization of the wadi Inaouène watershed based on morphometric analysis. The river system was extracted and thirteen sub-catchment basins have been delineated from a DTM using open source software. The following morphometric parameters were calculated for each sub-basin stream length (Lu) and the average length (Lsm), flow length ratio (RL), bifurcation ratio (Rb), medium bifurcation ratio (RBM), drainage density (Dd), drainage texture (T), the flow rate (Fs), elongation rate (Re), circularity ratio (Rc), form factor (Ff), topography and terrain ratio. By combining the values of these parameters we have classified the sub-watersheds in three prioritization categories: high grade (SBV01, SBV04, SBV05, SBV06, SBV11 and SBV12), is subject to a maximum soil erosion, which requires immediate action to prevent possible natural hazards, the Average category (SBV02, SBV03, SBV07, SBV08, SBV09 and SBV10) and low grade (SBV13).