Spatial-temporal assessment of soil erosion using the RUSLE model in the upstream Inaouène watershed, Northern Morocco

Abstract

This study aims to assess the risk of soil erosion in two different years (1984 and 2022) to gain insights into the extent of soil loss risk in the study area spatially and temporally. Using the Revised Universal Soil Loss Equation (RUSLE), which evaluates the soil loss rate, focusing primarily on erosivity of rainfall "R," soil erodibility "K," vegetation cover "C," topography "LS," and anti-erosion practices "P." To achieve this, we incorporated various factors of the equation into a Geographic Information System (GIS) and spatial remote sensing. By overlaying these factors, we obtained a quantitative map of soil losses in our watershed. The results of this work show that the upstream Inaouène experienced a strong erosion dynamic in both 1985 and 2022, with a notable decrease in the amount of soil loss in the last year. Soil degradation in 1985 had an average of about 68 (T/ha/year), with maximum and minimum losses between 2162 and 0.067 ​T/ha/year, while losses in 2022 recorded an average of 52.4 (T/ha/year), with a maximum of 1850 (T/ha/year). The study area represents very high quantities of losses in both periods compared to several studies conducted in this region using the same model. This is due to the fact that the study area is located in a region characterized by very favorable natural and human conditions and factors to trigger and promote significant soil losses, including concentrated and intense rainfall, the predominance of fragile rocks, steep slopes, low vegetation cover in the eastern and southeastern part of the terrain, in addition to irrational human interference with the land.