Geoelectrical study on the groundwater occurrence in delta Wadi el-Maehashi el Aala, Taba, southern Sinai, Egypt

Abstract EN

The area under study lies at km25, south Taba along Taba-Nuweiba road covering Wadi El-Maehashi El Aala (2km2).

Geomorphologic ally, the area is represented by a minor basin of the Gulf of Aqaba drainage system.

It runs nearly in NW-SE direction.

It drains from the water divide of Wadi Watir.

Stratigraphic ally, the study area is occupied by wadi deposits belonging to Quaternary over the basement rocks of Pre-Cambrian.

This study aims to construct a desalinization plant depending on groundwater of rather low salinity than the sea water to cover the demands of the new tourist village.

Beside the determination of the upper surface of the basement rocks in the subsurface to find out the large thickness that to suitable sites for drilling wells. For this study, a grid pattern of 18-Vertical Electrical Soundings (VES) of Schlumberger configuration was carried out in the study area.

The maximum distance between the current electrodes is ranging between 500 and 2000m.

The location and the ground elevation of these stations are estimated.

These soundings have been interpreted both qualitatively and quantitatively to make geoelectrical profiles, panel diagram and maps to evaluate the groundwater conditions and to locate the suitable site or sites of drilling wells.

The geoelectical succession consists of 4-geoelectrical zones (“A”, “B”, “C”, and “D).” Surface zone “A” consists of loose sand and composed the top cover of wadi deposits, zone “B” is represented by dry wadi deposits of sand, gravels, boulders, silt and clay.

Zone “C” is the waterbearing formation divided into three units (C1, C2 & C3).

Where, unit “C1” is saturated with brackish water and consists of wadi deposits, unit C2” consists of the same deposits of unit “C1”, but is saturated with high saline water due to the sea water intrusion, unit “C3” consists of saturated fractured basement rocks and zone “D” is represented by the crystalline basement rocks. Generally, the resistivity values of these zones increase towards the NW direction of the area which is attributed to decrease of clay percent and effect of coarser grains.

The decrease of resistivity in zone “C” is due to increase the water salinity and clay intercalation.

The thickness of the water bearing zone “C” increases gradually towards the Gulf According to this study, three sites were recommended for drilling of production and injection wells.