Identification Of The Hydrogeochemical Process In Zahrez ‎basin, Algeria

The Zahrez basin (Fig.1) is one of the endorheic basins of the ‎vast steppes region in the central northern part of Algeria. The ‎Zahrez hydrological basin covers approximately 8,989 km2. ‎Topography of the area is relatively flat with an elevation ‎ranging from 900 to 1330 meters above mean sea level. The ‎catchment lies between longitudes 2° 15’ to 4° 08’E and latitudes ‎‎34 35’ to 35 30’N. The area is characterized by a semi-arid ‎climate, typically Mediterranean, with an irregular annual ‎rainfall. The mean monthly temperature varies between 3°C and ‎‎25°C. The hydrogeochemical processes of groundwater in Zahrez ‎basin were identified based on the combination of geochemical ‎methods, graphical methods, and scatter diagrams. According to ‎the piper diagram, the dominant hydrochemicalfacies in the ‎study area is Ca-Mg-Cl-SO4, which represents 87% of the ‎samples. Mineral saturation indices calculated from major ions, ‎indicate that the groundwater is generally oversaturated with ‎respect to carbonate minerals and undersaturated with respect to ‎evaporite minerals, indicated that the chemical composition of ‎groundwater in the study area is influenced by natural processes ‎of water–rock interaction.‎