Characterizing the origins of groundwater salinity in the Mio-Plio-Quaternary aquifers of the middle eastern Cheliff basin in northwest Algeria using electrical resistivity techniques

The climate of northwestern Algeria's Middle Eastern Cheliff basin is mostly semi-arid. The main source of water for the municipal and private sectors is the shallow Mio-Plio-Quaternary groundwater system. However, deep saltwater intrusion has caused it to become significantly salinized in recent decades. Determining the lateral extent of the saltwater interface and determining the source of groundwater salinity are the goals of this study. This was achieved by conducting 30 vertical electrical borehole (VES) experiments and 8 electrical resistivity tomography (ERT) profiles. Fifty groundwater sampling locations were selected for in situ physical component analysis in order to evaluate the salinity of the groundwater. Furthermore, a total of 39 soil samples were taken from 39 different places. Each sample's soil 1:5 extracts were examined to determine the salinity of the soil.

The groundwater electrical conductivity geographical distribution shows extremely high values, increasing westward from 1020 to 14,700 μS/cm. The high readings found close to Dj. Tamoulga are indicative of the area's high groundwater salinity. A 1:5 diluted soil extract had an electrical conductivity of 200–2000 μS/cm. The western portion of the study area, near the DJ. Tamoulga periphery, had the highest values. On the other hand, the easternmost values were the lowest. A lateral difference in electrical resistivity for the various depths examined was also discovered by the geoelectrical investigation. In general, the resistivity falls from east to west and rises from north to south with distance from DJ. Tamoulga.

This study demonstrates that deep-seated faults beneath the aquifer close to the Dj. Tamoulga are the source of groundwater salinity.