Assessment of coastal groundwater recharge in a humid tropical zone by the method of Thiessen: Case of the Terminal Continental of Abidjan (Côte d'Ivoire)

This work aims to test the polygons' method of Thiessen, initially used to evaluate the average rainfall for assessing a groundwater recharge. The study concerns the groundwater of Terminal Continental, the main source of water alimentation of Abidjan population. The database is constituted by rainfall (three stations) and piezometric data (ten piezometers). This method has been tested on both cases: in surface for calculating the total recharge and in saturated zone for assessing the true recharge. The results showed that the ground water of Abidjan total recharge is estimated to 252 mm.year-1; the one estimated in saturated zone is equivalent to 158 mm.year-1 in 2006, that is to say 12 pc of the total infiltration. The taking account of "land use" factor in the approach underlined the fact that the quick ongoing urbanization of Abidjan city is reducing the infiltration zones.