Land use and hydric erosion assessment in a Mediterranean mountain environment: Case of Wadi Ourtza sub-basin (Eastern-Prerif, Morocco)

Abstract

The spatial distribution of land use and soil loss in the hydrographic sub-basin of the Oued Ourtza (Eastern Prerif, Morocco) between 2000 and 2014 is the subject of this study. We have extracted the thematic information from satellite imagery for the mapping of land occupation and then used geographic information systems for the spatialisation of water erosion according to the universal equation for soil loss in its version adapted to Mediterranean conditions. The resulting maps show an increase in the areas of arboriculture and a significant abandonment of land (36.8 %). The soil losses are quite high (40 t·ha-1·yr-1) and well above the tolerance threshold; although they are similar to ablation rates in some areas of the Mediterranean environment and the Moroccan Rif. These losses are unevenly distributed, with the highest rates corresponding to uncultivated or abandoned land (>80 t·ha-1 ·yr-1) whose extension continues to increase, especially in the middle and lower reaches of the sub-basin where fragile materials dominate.