Assessment and mapping of water erosion by the integration of Gavrilovic’s “EPM” model in the MENA region: case study of the Admer-Ezem sub-watershed, upper Oum-Rbaa basin, Morocco

The main goal of the research is to assess soil erosion while analyzing the spatial distribution of its evolution using the EPM (erosion potential model). Situated northwest of the upper Oum-Rbaa watershed in Morocco, the Admer-Ezem watershed is part of the research area. Its climate is Mediterranean, ranging from semi-arid to subhumid bioclimate, which favors fairly scattered vegetation and poor soil. Separating the factors of complexity and interdependence in the analysis of erosion risk was made possible quickly and effectively by the Geographic Information System (GIS) integration of thematic maps of the various Gavrilovic Equation EPM factors with their databases. It also made it possible to evaluate each factor’s influence and determine how much it contributed to soil loss. The priority of the various watershed regions was made possible by the use of Gavrilovic’s calculations. This basin covers a total area of 197.59 km², experiences relatively abundant rainfall (800 mm/year), and is subject to significant anthropogenic pressure. This will have an impact on the overexploitation of natural resources in general and soils in particular. Excessive use of agricultural land has led to its fragility and increased susceptibility to erosion. These natural and anthropogenic conditions have induced an intense erosive dynamic, which can be seen in its various forms (badlands, landslides, flows, concentrated active ravines…). The use of the “EPM” model for estimating soil losses approximates the severity of the erosion phenomenon. Soil loss due to water erosion according to the model used is estimated at 32.89 t/ha/year as the highest value and 0.11 t/ha/year as the lowest value. In addition, the analysis of these results made it possible, using GIS, to determine the factors that control water erosion.