Hydrodynamic, Hydro-Chemical and Isotopic Characteristics of Karst Aquifer: Case Study Aïn Kebrit Spring in a Complex Diapirs Zone (Northwestern Tunisia)

Karst aquifers play a fundamental role in the water supply of northwest Tunisia, especially in the Teboursouk region. Due to their specific hydrogeological properties, these aquifers are difficult to exploit due to their complex and heterogeneous structures. To better understand karst aquifers, different research methods are used to study the karst groundwater system in Aïn Kebrit Karst spring. It is thermal warm water (20°C) of Teboursouk region (northwestern Tunisia). The study area is characterized by sub-humid to semi-arid climate expressed by elevated and irregular rainfall associated with complex geological and tectonic structures dominated by Triassic outcrops “diapir zone” in the study area Karst system is an essential and even unique water resource. The present work attempts to investigate the geological, hydrogeological, hydro-chemical and isotopic data of Aïn Kebrit Karst spring water. The results will help in the identification of the main process and factors controlling groundwater mineralization. The water quality is dominant by Ca–Mg–Cl–SO4. The Total Dissolved Solids (TDS) values varied between 10 and 14.4 g L–1. The hydrochemistry of this water was linked with carbonate weathering and evaporates dissolution of Triassic outcrops. The results obtained by the different types of isotopic analyzes (δ18O = −5.8‰ V-SMOW and δ2H = −34‰ V-SMOW) show that it is a mix of old water (deep warm water) and recent water (cold superficial and meteoric).