Hydrogeological and geochemical characterization of groundwater in the F'Kirina plain (eastern Algeria)

Abstract

The F'Kirina plain in eastern Algeria is an endorheic basin suffering water scarcity due to a combination of natural and man-made causes. Its hydrogeological system is complex as made by interconnected aquifers represented by Mesozoic, Cenozoic, and Quaternary lithological units. The combination of drought indicators and water level data shows that a groundwater drought affected the plain during the last 15 years, which reflects on current water quality. The reported geochemical analyses, including major ions and trace elements, indicate that the groundwater resource is suffering from salinization, mainly due to evaporation and leaching of soil salts, a process that is coupled with simultaneous cation-exchange effects. In this framework, we observe a geochemical evolution from the fresh Ca–HCO3 facies, typical of springs bordering the plain, towards more saline groundwater characterized by chloride/sulphate-rich facies in the middle of the plain approaching the sebka. However, geochemical diagrams indicate that in few wells salinization is also influenced by upraising of deep groundwater. The water isotopic composition of the F'Kirina plain samples suggests that they diversely record both recharge and evaporation components. Moreover, the most 18O and D depleted compositions among the investigated ground-waters suggest recharge contributions by comparatively higher elevation or the involvement of old (fossil) water components.