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

Abstract

The main goal of the research is to assess soil erosion while analyzing the spatial distribution of its evolution using the empirical erosion potential model, or EPM. Situated northwest of the upper Oum-Rbaa watershed, the Admer-Ezem watershed is part of the research area. Its climate may be described as semi-arid Mediterranean. The quality of the soil could be better. 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)'s 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, and is marked by relatively abundant rainfall (800 mm/year), and under strong anthropogenic pressure. This will have an impact of 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, and flows, concentrated active ravins…). 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 53.34 t/ha/year as the highest value. And 597.642 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 and which are, in order of importance: rainfall, slope and soil sensitivity and soil protection. rainfall, slope, soil sensitivity, and soil protection, in that order of significance.