Hydrogeochemical characterization of water mineralization in Tebessa-Kasserine karst system (Tuniso-Algerian Transboundry basin)

Abstract

Carbonate aquifers provide large parts of the water supply for more than a quarter of the world’s population. The geochemical assessment of these heterogeneous aquifers is a valuable endeavor to ensure a rational management and protection of groundwater resources. To secure its durability, regard to increasing water demands and climate challenges make the problem of prevalence of water scarcity, vulnerability, and drought conditions extremely complicated. In Tebessa–Kasserine basin (Tuniso-Algerian international border), karst aquifers are receiving increasing interest, as the area has typical karst landscape and the hydrogeological system mostly consists of carbonates formation. Thus, a thorough understanding of aquifer behavior and water mineralization origin using geochemical and statistical tools can lead to relevant information regarding karst processes, groundwater chemistry, and protection. Subsequently, this study represents a pioneer baseline of the hydrogeochemical characterization of karst features in this international border area and it aims to identify the origin of karst water mineralization, its spatial distribution, and factors influencing water composition. The hydrogeochemical assessment of the sampled waters shifts from low mineralized Ca-HCO3 waters to Ca-SO4 and Na–Cl water types. TDS values range from 10 to 490.66 mg/l. A Gibbs diagram indicates that karst waters have been recently recharged by direct rainfall infiltration. Water quality gets modified along pathways and dissolution, formations weathering, and ion exchange processes seem to be the predominant geochemical factors influencing water mineralization. The PCA confirms the spatial variability of water types and indicates that it largely depends on aquifer lithology and on geographical position of water points.