The synthesis of geological and petroleum research undertaken in the coastal Sedimentary Basin of the Pointe-Noire region enabled the establishment of a lithostratigraphic scale.
It has been observed that the order in which the series observed in outcrop and those encountered by deep wells succeed each other has allowed a value to be given to this relative scale. The study area corresponds to a longitudinal tectonic accident, fault or flexure.
It belongs to the Cretaceous and Tertiary coastal sedimentary basin covered by the Plio-Pleistocene age formations series of circuses , formed of highly permeable sands comprising multiple resistant horizons that store large bodies of water whose reserves are considered very important. Hydrographic network is composed of four main basins with a mediocre size. The quality of this groundwater is considered to be satisfactory for household consumption, but the sustainable management of these reserves requires constant checks on their quality as well as on the level of the reserves.
All these resources put the agglomeration of Pointe-Noire close to large exploitable water reserves that meet the need for drinking water, even if, on the whole, the agglomeration is still experiencing many difficulties in terms of its drinking water supply. A number of research studies [1] [2] [3] [4] [5], and monitoring projects [6] [7] [8] [9] have been carried out since the s to assess the hydraulic potential of these reservoirs. However, the results obtained on knowledge of water resources are still insufficient compared to the challenges of this region: 1 the ever-increasing population of the region, which is increasing the demand for water and the need for hydraulic structures that have not yet been fully met; 2 growing demand for water for agriculture and industry needs; 3 climatic variability that can lead to a decrease in groundwater recharge and groundwater supplies; 4 the risks of actual pollution of the water tables by salt intrusion on the one hand and by domestic and industrial discharges hydrocarbons, various effluents and by land use eucalyptus forests on the other.
Hence there are still uncertainties about 1 the configuration of the aquifer system in the area; 2 the relationships between the aquifers; 3 the hydrodynamic functioning; 4 also the chemical quality of the waters and its evolution over time.
