Laassab AbdennasserKaoua Moustapha2024-02-292024-02-292018-06-20577-063-Mhttp://dspace.univ-khenchela.dz:4000/handle/123456789/2512Abstract This work aims to map the salinity of groundwater in the southern region of Garaet El Taref and to determine the origin of strong mineralization (EC between 1300 and 2060 μs / cm). The waters of the analyzed samples have three hydrochemical facies: chlorinated and sulphated calcium and magnesium, sodium chloride and potassium or sulphated sodium. The calcic and magnesium Bicarbonate facies are found in the south-eastern part of the watershed where there are formations rich in bicarbonate (Upper Cretaceous limestone). The magnesium content comes from the dolomitic limestones of the Triassic. The contamination of groundwater by nitrates is of urban and agricultural origin very likely given the context of the zone. A geographic information system was used to develop the maps of the isovalues of the concentrations of the chemical elements and indicates the variation of the spatial distribution of these elements. The samples with high mineralization are relative to the places close to Garaet and to the sites of anthropogenic activities.frThesis