Hydrogeochemical processes and multivariate analysis for groundwater quality in the arid Maadher region of Hodna,northern Algeria

This study focused on water quality and hydrogeochemical processes(evolution, origin) in the Maadher region, central Hodna in Algeria. In recent decades, the excessive exploitation of this resource due to urbanization,irrigation, and the effect of climate change reaching the countries of northern Africa have caused a decline in water levels and hydrochemical changes in the aquifer. The sampling campaign in 2019 based on 13 physicochemical parameters was carried out on the water from 32 boreholes in the study area, compared to data archives of both sampling campaigns in 1967 and 1996. The result revealed that the groundwater as a whole has moderate freshwater quality, due to its total dissolved solids(TDS) content and other dissolved ions of concern(nitrate NO3~-), which exceed WHO standards. In addition, Piper diagram indicates that the hydrochemical facies of sulfate–chloride–nitrate–calcium(SO42-–Cl~-–NO3~-–Ca2+type), which globally characterizes the study area and these elements are the dominant dissolved ions. Principal component analysis and hierarchical cluster analysis(HCA) methodologies are applied in order to define the major control factors that affect the hydrochemistry of Maadher plain. Three distinct water groups were found, illustrating a different evolution of salinity(EC and TDS). The HCA indicated an interesting cluster with a distinct contamination signature and most likely with significantly higher sulfate, chloride, and nitrate concentrations. Anthropogenic processes also play an important role in the study area. The water resource comes from Bousaada Wadi, the exchange at the aquifer depth and the agricultural practices contribute to the deterioration of the quality.