ASSESSMENT OF GROUNDWATER EFFECTIVE VULNERABILITY TO POLLUTION THE CASE OF THE LOBO WATERSHED BUYO, SOUTH WEST OF COTE D’IVOIRE

Rapid and uncontrolled urbanization as well as agricultural activities constitute real threats to groundwater which represents one of the most important natural resources for the supply of drinking water, especially in developing countries. The objective of this study is to assess the risk of pollution of these resources. The method consisted of integrating the intrinsic vulnerability map with that of the pollution indices produced from the pollutants. These pollutants considered as those which threaten the quality of groundwater in the area have been determined using the method of Principal Component Analysis (PCA). The results obtained present an intrinsic vulnerability map dominated by the medium intrinsic vulnerability class. The statistical tests made it possible to identify the land use pattern and the nitrates which were combined to produce the pollution index map. The result of the combination of these two maps shows that the study area remains dominated by the average effective vulnerability class. However, the effective high vulnerability class which shows the areas most threatened by pollution is more observed in the South with a few low occurrences in the North.