CONTRIBUTION TO THE HYDROCHEMICAL KNOWLEDGE OF AQUIFERS IN THE DEPARTMENT OF TANDJILE-EAST, SOUTHERN CHAD

The province of Tandjile is one of the 23 provinces of the Republic of Chad. The drinking water supply rate in this region remains low. Part of the population obtains its water supply through open wells and / or surface water. Climatic and anthropogenic variations in recent years have shown how much groundwater can be influenced both in terms of its quality and its quantity to be used. The objective of this study is to provide knowledge on the state of the hydrodynamic and hydrochemical parameters of the aquifer of the department of Tandjile-Est to help decision-makers in their approach. This study is based mainly on existing data collected in Chadian institutions and literary journals. The analysis of these data showed that the lithology is represented by clayey, sandy, lateritic formations and clay-sandy mixtures. The aquifers are sandy and sandy-clayey. The groundwater temperature values are in equilibrium with those of the air, the pH shows values close to neutrality and the electrical conductivity below standards (Chad, WHO). The groundwater in the study area is not very mineralized and the concentrations of elements indicating contamination (nitrates, chloride, etc.) are clearly in traces. Chemical analyzes revealed two chemical facies: calcium and magnesium bicarbonate and sodium and / or potassium bicarbonate.