Vulnerability of ground water to polution in the highlands by a combined approach of AHP method and remote sensing

Abstract

The aim of this work is to develop a simple and convenient decision support tool for the highlands using a combined approach of the Analytic Hierarchy Process (AHP) method and remote sensing. The vulnerability assessment method developed is called O3P (Highlands method). It is a parametric method, adapted in the highlands and implement in the town of Bafoussam. This method takes into account 4 factors, including land use (O), permeability (P1), slope (P2) and water depth in the piezometers (P3). The AHP multi-criteria analysis coupled with geographic information systems (GIS) and the analysis of nitrate pollution, allowed the development and validation of the O3P method. The results obtained show 3 classes of vulnerabilities which evolve from the low vulnerability class (20.22% of the study area) to the classes of medium vulnerability (50.16 %) and high vulnerability (29.62 %). Classes of high vulnerability to pollution are more present in the central-northern part of the study area, with some occurrences towards the south. The superposition of the highest nitrate concentrations with the areas of high vulnerability confirms the validity of the method. It emerges from it following the study of the sensitivity that the land occupation factor has the most important effect in this model and whose reduction would influence to 35.54% the method. The statistical study shows that this method is acceptable because the value of the standard deviations of the IVO3P lower than that its mean.