Abstract
Groundwater is the main source of drinking water supply to Abidjan District. However, the rapid growth of Abidjan population and the highest demand in water are a threat quantitative of this resource. This study has been undertaken by means to obtain the order of drawdown magnitude of Abidjan aquifer on the horizon from 2005 to 2030 according to an increasing in flow rates of pumping stations provided by SODECI to satisfy the highest demand in drinking water. To achieve such an objective, a hydrogeological model of Abidjan aquifer has been designed using the code MODFLOW by using historical data (geological, hydrogeological and piezometric) to predict the impact such an exploitation on this aquifer. The numerical model designed was calibrated in steady-state mode with piezometric data from 1978 and then validated in transient mode from piezometric data from 1992. The piezometry evolution simulation and the drawdown calculation from 2005 to 2030 were made in transient mode. The results of this model revealed that the project of rates increase from 2005 to 2030 is possible. These flows will pass from 256 490 m3/day to 310 760 m3/day. However, the highest drawdowns will be observed into piezometers; Anonkoua kouté 2 (15.71 m), Niangon 1 (6.86 m) and Adonkoua (6.24 m).