Évaluation De La Vulnerabilite A La Pollution D'une Eau De Surface Destinee A L'adduction D'eau Potable D'une Metropole. Cas De La Lagune Aghein A Abidjan, (Sud De La Cote D'ivoire)

Abstract

The lagoon that is the subject of this study, was chosen as drinking water alternative source of supply for the city of Abidjan. However, this language is shown in a very favorable area of forest to agriculture. We observe large rubber plantations, food and oil palm crops spread throughout the lagoon basin. Also, fertilizers injected into these plantations, as well as releases from industries and homes they are potential sources of pollution of the lagoon. According Humbert (2012), this pollution is reflected in particular by widespread concentration of nitrates and pesticides. Given these observed problems related to the quality of this resource, this study was initiated. Its objective is to develop a methodology based on the functionality of a Geographic Information System (GIS) to assess the degree of threat to what the Aghein lagoon faces through the completion of a vulnerability map at pollution. The method used here is a spatial analysis model incorporating several parameters including the slope, land cover, soil type, runoff and drainage density. These parameters have been previously defined, prioritized and weighted, and then integrated into a GIS. The resulting map shows five classes of vulnerability indices to pollution of the lagoon Aghein. They are: very small classes, low, medium, high and very high. These indices highlight the areas from which the lagoon is threatened.