| Popis: |
The large demand for drinking water in the Baya watershed (6324 km2), located in East of Cote d’Ivoire is supplied from groundwater sources. This study investigated the specifics hydrogeochemical assessment of groundwater quality in the Baya’s watershed by using statistical methods with graphical and self-organizing maps (SOM) neural network methods. It was carried out to identify the hydrogeochemical processes related to groundwater quality, conduct a hydrochemical evaluation of the aquifer systems and delineate the various factors controlling the water chemistry and general suitability for drinking purposes. To reach these goals, groundwater was sampled from 150 locations. Results indicated that the groundwater sampled is generally acid due to the acid character of the enclosing rocks (SiO2 > 60), with an average pH of 6.54 ± 0.33 and an average electrical conductivity of 420.15 ± 248.15 μS/cm. they are moderately mineralized to the gaze of World Heath Organization (WHO) guidelines, with calc-magnesium hydrogen carbonate facies (84%) and calc-magnesium sulphate chlorinated facies. Major ions at the origin of mineralization of groundwater are produced by rock weathering, hydrolysis of silicate minerals. The NO3-, Cl- and SO42- ions are derived from a human pollution due to human activities. Water boreholes located along the major rivers and the watershed outlet are highly mineralized but also proned to anthropogenic pollution. As for the locations of the north and southeast of the Baya’s watershed, there are high levels of iron and manganese, which explains the reddish appearance of these waters. Key words: Hydrogeochemistry, mineralization, fractured Aquifer, self-organizing map (SOM), watershed of Baya. |
