Contribution of Geostatistical Methods to Water Quality Assessment: a Case Study of the Tebessa Plain (Easternmost Algeria)

In the Algerian-Tunisian border region lies the Tebessa plain, which belongs to the Saharan Atlas domain and is characterized by a semi-arid climate and high salinity, often rendering the groundwater unusable. The objective of this research is to highlight groundwater salinization using statistical and geostatistical methods to model this spatial heterogeneity. A total of 30 data points were used, and the statistical analysis revealed a strong association between chlorides, sulfates, electrical conductivity, and values significantly exceeding the standards. Surface and directional variograms for EC (electrical conductivity), SO4 (sulfates), and Cl (chlorides) exhibit anisotropy, with the major axis showing a hole effect and a periodicity of 5 km. Geostatistical mapping through ordinary kriging allowed us to identify areas of high salinity and deduce the underlying cause; which is the dissolution of gypsiferous formations. These results were confirmed by thermodynamics and Sr2+/Ca2+ ratio.