Integrated statistical and hydro-geochemical approach to identify the origin and process of saline contamination of Remila plain groundwater (Khenchela, Algeria)

Abstract

ABSTRACT Groundwater is widely used in the semi-arid region of Remila plain (Khenchela, Algeria) for urban and agricultural supplies. An integrated statistical and hydro-geochemical approach was performed with 70 water samples in order to identify the main processes and the origin of water salinisation. The results have suggested the dominance of three chemical facies: Sulphato cloruro calcic (SO4–Cl–Ca) in the northeastern part, Sulphato cloruro calci magnisian (SO–4Cl–Ca–Mg) in most of the waters andalkali-earth bicarbonate (HCO3–Ca–Mg) in the southeastern part. Although based on principal component analysis and hierarchical clustering analysis, the statistical approach identified three water groups: (1) saline water (17 %; total dissolved solids >1000 mg l−1 with the dominance of Sulphate (SO42−)); (2) moderately saline water (17 %) with a dominance of bicarbonate (HCO3−); and (3) moderately saline water (66 %) with mixed facies. The binary diagrams confirmed the predominance of three processes: evaporite dissolution and/or precipitation, combined by ionic exchange. In the northeastern part of the area, however, another process was detected – the saline intrusion of Sabkha water, favoured by extensive groundwater use.