Assessment of soil erosion rate using the EPM model : case of Ouaoumana basin, Middle Atlas, Morocco.

Abstract

Soil erosion and land degradation are considered serious problems, decrease soil fertility, flooding, and silting of dams, which makes soil conservation and control of erosion risk are basic issues in all countries. The crucial aim of this study is to evaluate the soil erosion rates and to spatialize its hazard, by applying an empirical model namely the erosion potential model (EPM), known also as the Gavrilovic method. Located in the Middle Atlas of Morocco, the chosen study area is known as the Ouaoumana basin, which is a small mountainous area. In terms of climate, it can be classified as the Mediterranean with mountainous influence. The studied area is characterized by an annual rainfall average range between 378 and 513 mm. Consequently, the obtained results were evaluated using GIS software and compared in terms of two different representative catchments. The criteria of selecting the two studied headwaters are; different localization within the Ouaoumana basin, land uses, slopes, and lithology. The Tiguert catchment (a) which is located in the downstream part, is moderately eroded with a rate of less than 39007 m3/km2/yr-1. In inverse, the Wanmroud catchment (b) is situated in the upstream part of the studied basin, and is highly eroded due to lithology, slopes, and land use impacts. Besides, within this catchment (b) the produced soil erosion rate varies from 222 to more than 164420 m3/km2/yr1.