The concerned area (the upstream portion of Wadi El Kharit) has been geophysically studied applying of Land Magnetic, Vertical Electrical Sounding and Electrical Resistivity Imaging techniques. The aim of this
study is to evaluate the groundwater potentiality along the main channel of Wadi El Kharit.
The land Magnetic Survey was accomplished through measuring 1740 stations along 3 profiles. Its interpretation revealed the configuration of the upper surface of the basement and faults that affect the basement blocks along these profiles.
The geoelectric resistivity survey includes 28 vertical electrical soundings and five resistivity imaging profiles (2-D). The subsurface succession downward consists of three geoelectric zones: dry wadi deposits composed of silt, sand, gravel and rock fragments as well as two water-bearing layers, the first layer is composed of wadi deposits (detected only at some sites) and the second is the saturated fractured basement rocks and the last zone is dry massive basement rocks.
The results of interpretation revealed that many faults affect the main stream of Wadi El Kharit. The two water bearing layers are; the upper layer consisting of wadi deposits (at VES No's 9, 10, 11, 12, 24, 25, 26 and 27) and an underlying layer consisting of fractured basement. In the upstream of the wadi, the only water bearing layer is the fractured basement (at VES No's 1, ….., 6, 13, …..23 and 28). While no groundwater is detected at the sites of VES No 7 and 8 due to a horest block of the basement at these sites. The results showed also that the basement relief and dykes as well as intersecting faults control the groundwater occurrences in the area. It was concluded that the promising parts of the area as to groundwater occurrences are those covered by VES stations 2, 6, 6, 10, 11,13, 16, 24, 25 and 26, where groundwater was detected at a depth of 8–18m.
Keywords: geophysical techniques, Land Magnetic, Vertical Electrical Sounding, 2-D resistivity.