Estimation and mapping of soil erosion using the RUSLE model and GIS tools: A case study of the wad El Hai watershed in the western Aurès, north-eastern Algeria

Abstract

Soil erosion is the main cause of siltation in dams, on the one hand, and it is one of the main causes of degradation of the agro-pedological heritage, on the other hand. In this context, this work aims to quantify the eroded soils and their spatial distribution in the watershed of Wad El-Hai (Aur?s, Algeria), reaching the Fontaines des Gazelles dam located at the outlet of this basin. The work focuses on mapping and analyzing various thematic maps representing the key erosion factors, linking the Revised Universal Soil Loss Equation (RUSLE), with the goal of producing a synthesis map providing a quantitative spatial representation of the extent of the phenomenon in the watershed. From this map, we can confirm that the erosion phenomenon affects the entire watershed of Wad El Hai. The most severe erosion, affecting 11.60% of the expansive territory at rates exceeding 33.6 tons per year per hectare, is predominantly concentrated in mountainous regions marked by exceptionally steep slopes. Conversely, the majority, accounting for 64.23% of the entire expanse, is situated in the plains, where erosion rates are comparatively lower at 6.7 tons per hectare per year. The assessment of potential water erosion yields disconcerting outcomes, projecting an average annual loss rate of 15.38 tons per hectare throughout the entire catchment area. The results presented in this study will serve as a vital resource and a decision-making tool, supporting the management and preservation of natural resources by policymakers and stakeholders.