Maps of vulnerability to pollution: a useful tool for sustainable groundwater in Douala, Cameroon

This study is a help approach to protect and prevent pollution of the unconfined aquifer of Douala sedimentary basin. It was conducted in order to identify areas at high risk of contamination and protect them in the long-term. Maps were validated based on field measurements. The assessment was conducted using DRASTIC and GOD methods. Statistical analysis of the maps of vulnerability reveals the concentration of three classes. These methods show on the one hand that the study area has a high risk of contamination and in the other hand that DRASTIC best reflects the reality of the groundwater pollution. Finally maps of vulnerability permit to stakeholders to adopt two decisions: protect this unconfined aquifer needed by 57% of the population for water supply by deleting pit latrines inside a radius of 50 m from a well and; use water of boreholes for human consumption.