Erosion sensitivity mapping using GIS-based multicriteria analysis—case study of the semiarid Macta watershed, North-West of Algeria

The exponential rise in the natural risk related to the soil erosion and important impacts resulting in the human activities was strongly threatening the biological richness of different regions in Macta watershed located in the North-West of Algeria. This serious and complex situation has been an environmental concern in Algeria. Soil erosion depends mainly on a combination of factors such as climate (rainfall), topography, vegetation cover, type of soil, and land use (agricultural activities). The study aims are to develop a methodological approach, based on the combined use of geographic information system, remote sensing, and a set of multicriteria analysis methods such as analytical hierarchy process, PROMETHEE, dedicated to the soil erosion sensitivity mapping. The different factors are implicated in a geographic database as layers to make it easier for their implementation in a decision aid dataset such as alternatives and criteria. Results showed that the dominant classes of the fragility to erosion correspond to low and moderate levels and only less than 8% of the watershed was vulnerable to soil erosion. The analysis of the maps obtained under GIS environment for different parameters shows that the areas with a high vulnerability to erosion are located in the North-East (part of sub-watershed: wadi El Hammam, wadi Mebtouh, and wadi Fekan) and someone in the South (part of sub-watershed: wadi Taria, wadi Saida) and West (North of Mekerrela and Louza sub-watershed).