Spatialization of water erosion using analytic hierarchy process (AHP) method in the high valley of the Medjerda, eastern Algeria

Abstract

The present study tries to quantify soil losses using Geographic Information Systems (GIS) and analytic hierarchy process (AHP) in the Medjerda watershed (Algerian-Tunisian border). The Analytic Hierarchy Process (AHP) method is used in the quantification of erosion qualitative characteristics, through its weighting. It is used for many problems requiring decision-making. This catchment area is characterized by moderately consistent lithology, irregular rainfall, medium slope and low vegetation cover, which makes it very sensitive to erosion. Therefore we claim to develop a spatialization map of vulnerable areas, based on analytic hierarchy process and GIS that define the combination of specific factors. The integration of the thematic maps of the various factors makes it possible to identify the impact of each factor in the erosion, to classify the sensitive zones, and to quantify the soil losses in the basin. This mapping will be an important tool for land use planning and risk management. From the distribution map of erosive hazards, we have identified four classes of vulnerability, areas with very high to high vulnerability are mainly in the northern part of the watershed (where the relief is very important).