Aquifer systems in dry regions: Hydro-geophysical and geochemical investigations providing insights into water resources in southeast Tunisia

¹ Higher Institute of Water Sciences and Techniques, University of Gabès, University Campus, 6033 Gabes Applied - Hydrosciences Laboratory, Gabès, Tunisia
² Institute of Earth Sciences, Pole of University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
³ LR: Applied Hydro-Sciences Laboratory Research Campus Universitaire, 6072 Zrig, Gabès, Tunisia

^* Corresponding author: imantunes@dct.uminho.pt

Abstract

Water demands from agriculture and industry have intensified groundwater extraction, prompting a focused study to bolster water resources, particularly at Gabès region (Southeastern Tunisia). Through extensive geologic and geophysical investigations, the reservoir geometry and structural architecture of crucial aquifers, notably the Mio-Plio-Quaternary and Cretaceous aquifers have been studied. The integration of geochemical and geophysical data allows for a nuanced assessment of fault structures and groundwater hydrodynamics. Advanced techniques, like horizontal gradient and upward extension unveils structural features and density contrasts with precision. This study extends to a spatiotemporal analysis of aquifer hydrodynamics and groundwater mineralization. The Gabès aquifer system exhibits four groundwater facies: Ca–Mg–SO₄, Na–Cl–NO₃, Ca–Mg–HCO₃, and Na–K–HCO₃. Results reveal relative isotopic depletion, suggesting recharge under colder climates and at higher altitudes. However, the study underscores the impact of climate change, with increasing temperature and dwindling precipitation in North Africa, since the mid-20th century. This research is a relevant contribution to sustainable water management by emphasizing the impact of climate change scenarios and groundwater resources management. The detailed exploration of hydrogeological characteristics and aquifer dynamics in the Gabès region is pivotal on effective management of groundwater resources strategies in semi-arid environments.