Contribution of Hydrochemical and Geoelectrical (ERT and VES) Approaches to Investigate Salinization Process of Phreatic Aquifer and Climate Change Adaptation Strategy in Arid Area: Example of Garaat Douza and Its Proximities (Mediterranean Basin)

Abstract

The geophysical, hydrogeochemical and climatological investigations of the plio-quaternary aquifer, in Garaat Douza (Moulares-Redayef Mining Basin, Southwestern Tunisia), enabled us to identify the origin and the extension of salinization in time and space. Thus, the hydrogeological study has revealed a piezometric draw-down, showing the insufficiency of the natural recharge of the aquifer due to the low rainfall events and the increasing use of groundwater. The hydrochemical study has shown that the high salinities are recorded at the level of Garaat Douza (outlet of the aquifer). The geophysical study (ERT and VES) has revealed that the surveyed area is characterized by the presence of two zones with different resistivities. The first zone is near the outlet, and generally has very low resistivity values (less than 3 X m) revealing the presence of salt-water, whereas in the second zone (far from the outlet), the resistivity values are higher than 100 X m, testifying for the presence of water with a better quality than the previous one.