Spatial Assessment of Soil Erosion Using RUSLE Model, Remote Sensing and GIS: A Case Study of Mellegue Watershed, Algeria- Tunisia

Abstract

Soil erosion is an important global phenomenon that can cause many impacts, like shape and hydrology alteration, land degradation, and landslides. Moreover, soil loss has a significant effect on agricultural production by removing most valuable and productive top soil’s profile, leading to reduction in yields which requires high production budget. Soil erosion impact has been intensified by the magnification of global warning and drought, especially in north African regions, such as Tunisia and Algeria, where arid climate is the dominant weather on these regions. In addition, these regions are suffering from soil erosion by water which had cost a serious soil loss regionally and globally. Accordingly, this study aimed to compare soil losses, between 2002 and 2020, of the catchment of Mellegue which is a large cross-border basin commonly shared between Tunisian-Algerian countries. Soil erosion risk was assessed and mapped via the Revised Universal Soil Loss Equation (RUSLE). It requires diverse factors that are integrated in the erosion process such are topography, soil erodibility, rainfall erosivity, anti-erosion cultivation practice and vegetation cover. The computation of the various equation factors was applied in a GIS environment, using ArcGIS desktop 10.4. The results shows that the catchment has undergone significant soil water erosion where it exhibits the appearance of approximate 14000 new areas vulnerable to erosion by water in 2020 compared to 2002. Average erosion risk has also increased from 1.58 t/ha/year in 2002 to 1.78 in 2020 leading to an increase in total estimated soil loss by reaching 54000 t/ha in 2020 compared to around 25500 t/ha in 2002. Mapps of erosion risk shows that highly eroded areas are more frequent in downstream of the basin. These maps can be helpful for decision-makers to make better sustainable management plan and for land use preservation.