Climate change is having short-and long-term impacts on surface and groundwater in the northern part of the African continent. This has led to a wide range of consequences that have added pressure on the groundwater systems in this part of the world. Among such pressures, we can cite the mal-distribution and the irregularity of precipitation and ice, flooding, evaporitic sediments input by the drainage net, water degradation, mud stagnation in dams, dead tranche, drought, decreasing of the natural recharge and increasing of the groundwater abstraction, conflict between trans-boundary waters, desertification, imbalance between the regions, migration, revolution, socio-economic imbalance, etc. Actually, watermonitoring networks indicate noticeable hydrogeologic variations and a rise of the groundwater salinity. It was confirmed by the geochemical analysis of water resources that showed scattered data between the northern part characterized by low mineralized groundwater (TDS ranging 0.4-3 g/l) and the southern area where the salinity ranges from 2.5 to 90 g/l. The obtained values are far above the permissible limits for both human consumption, agricultural and tourist activities. These effects, when compounded, are anticipated to worsen the situation and to constitute veritable threats for social and economic development in these regions of North Africa (Morocco, Algeria, Tunisia, Libya, Egypt, etc.). The potential solutions consist of taking urgent to utilize the intelligent technology (bio and nano-technology), policies relevant policies to manage water resources, and the engagement of private, civil, and international sectors if a major crisis is to be averted (collective effort).

In southern Tunisia, the lack of permanent surface water, associated with drought conditions, leads to an endless abstraction from the limited low renewable multi-layered aquifer system of Système Aquifère du Sahara Septentrional containing two principal aquifers, the complex terminal and the Continental Intercalaire (CI) multi-layered systems. The deepest aquifer embodies the low-enthalpy thermal resources of Southern Tunisia. The thermo-mineral surface manifestations of the conductively heated waters reveal the complexity of the geotectonic history of the region and create oases systems in net contrast to the desertic landscape of the Chotts region. As agriculture constitutes the principal economic activity in the studied area and as it is currently threatened by thermal water quality degradation, the present hydrogeological investigation aims for a characterization of the CI thermal resources on the basis of a critical quality evaluation. Thus, different geothermometry approaches have been applied to characterize the low-enthalpy thermal field showing a temperature ranging from 27 to 72 °C. The application of cations geothermometers owns to different temperature estimations ranging from 28 to 202 °C. Based on Na + -Mg 2+ -K + , K + -Mg 2+ -Ca 2+ and HCO 3 − -Cl − -SO 4 2− geoindicators, the CI thermal resources refer to immature waters characterized by MI varying from − 0.5 to 0.19. The assessment of groundwater chemical composition based on a Durov diagram proves that CI thermal water is governed by mixing between different water bodies with relative abundance of Na + , Cl − , and SO 4 2− elements. According to D'Amore genetic diagram and meteoric genesis indices, the analyzed groundwater derived from deep circulation in sandy formations. The water quality can change along fluid migration pathways expressed by scattered isotopic and chemical data and a number of mixing ratios. Most changes in the background CI composition result from continuous pumping that modifies natural flows and increase quality degradation.

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