Integrated Hydrochemistry and Statistical Methods to Investigate Groundwater Origin and Salinization Process in Arid Regions (Central-eastern Tunisia)

Abstract

Hydrochemistry is a discipline widely used given the groundwater quantitative and qualitative reliability in the hydrogeological study. The geochemical study of groundwater in the Nadhour-Sisseb-El Alem basin aimed to characterize the water chemistry, determination of the physicochemical parameters and chemical facies well as and the mineralization processes. The Piper and Durov diagrams and scatter plots, conventional classification techniques, are applied to evaluate the geochemical processes. Samples are classified using two multivariate statistical methods, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). Waters compositions are affected by cation exchange reactions in the intercalated clay, resulting in a Na+ increase, and peaks of K+, Ca2+ and Mg2+. PCA analyses show that the water samples have been classified into 8 groups. The waters quality deterioration is caused essentially by; overexploitation, decreased in freshwater recharge rates, climate condition; height evaporation low precipitation, artificial recharge by dam water, and irrigation return water.