Impacts Of Cracks On Underground Flows Of The Superficial Aquifer Case Of The Northern Sector Of The City Of Bangui.

Bangui capital of the Central African Republic is a city whose groundwater is fed by two aquifers one deep fissured and the other porous surface. The latter is a better transfer medium by runoff and underground flow for various pollutants from wastewater and anthropogenic activities. This study focuses on the impact of cracks on underground flow of superficial aquifer of the sector starting from an approach that takes into account firstly both the study of various geological formations of the northern sector structures and broad directions to which subsurface flows and secondly the physicochemical quality of the water wells sector. The different results allow to know the hydrogeological potential of the north of Bangui. Physicochemical and isotopic analyzes as well as in situ measurements show the influence of aquifer materials on water through water-rock exchanges through major ion concentrations Ca2Mg2KNaCl-SO42-HCO3-. The chemical composition of these waters depends on the geological environments crossed the runoff and infiltration that would have gained the surface water table. Two main factors control the mineralization namely alteration of the rocks composing the schisto-quartzitic superficial aquifer laterites and anthropogenic pollution through nitrates. The elevation of NH4 and NO3- levels shows a slight contamination due to the well-latrine distance. The results obtained made it possible to confirm the hypothesis of the impact of the fissures on the underground flows of the surface water of the north sector through the large fractures measured on the different formations translated by the piezometric maps.