An Integrated Assessment of Groundwater in an Anthropized Coastal Aquifer System Using Geochemical and Geophysical Methods (Eastern Tunisia, Mediterranean Region)

Water resources management within water-stressed coastal aquifers, specifically in the arid and semi-arid Mediterranean basin, engenders significant challenges. Their distinctive attributes, characterized by their proximity to the sea and their complex hydrogeological characteristics, contribute to the difficulties faced in their management. Factors such as high coastal population density, fast urbanization and industrialization, agricultural and touristic expansion, intensify the demand for freshwater, compounded by extensive groundwater extraction. Consequently, the relentless depletion of aquifers deeply affects the intrusion of salt water and the quality of groundwater resources. The Plio-Quaternary aquifer system in Eastern Tunisia, Mediterranean region, has experienced significant groundwater salinization since the 1970s. Field surveys and chemical analysis were conducted to measure different parameters such as groundwater static level, electrical conductivity, major elements, and nitrates. Accordingly, to understand the salinization processes, delineate salt groundwater plumes, and identify vulnerable areas, a geoelectrical approach was employed. These approaches were valuable in detecting salinized areas within the aquifers and comprehend the mechanisms of groundwater salinization. High salinity levels and interactions between groundwater and surface water were identified along the coast and near Sebkha Moknine. The hydrodynamic behavior of saltwater, whether it ascends or descends, directly impacts the hydrodynamic systems of the Mahkia Ksour Essaf aquifer and the overall groundwater quality. These investigations show valuable results to perform for a better management and prevention from pollution and overuse of water resources of the studied region.