STUDY OF GROUNDWATER OCCURRENCE AND THE IMPACT OF SALT WATER INTRUSION IN EAST BITTER LAKES AREA, NORTHWEST SINAI-EGYPT, BY USING THE GEOPHYSICAL TECHNIQUES

The study area lies between the Suez Canal from the west to El Tassa- Baloza Road to the east and between El Qantara Shark-Arish Road from the North and Ismailya-Gifgafa Road from the south, with an area of about 1200 km2. Since the liberation of Sinai, the sustainable development has caused an overgrowing need for water resources of this important region. The concerned area has been geoelectrically studied applying the techniques of Vertical Electrical Sounding and Electrical Resistivity Imaging. The aim of this study is to evaluate the groundwater conditions. A total of 64 Vertical Electrical Soundings and four 2-D imaging electrical profiles were carried out.
Geologically, the Quaternary deposits of northwestern Sinai area consists of gravel, sand and silt intercalated with clay. As a result, the upper part of the Quaternary deposits represents the shallow groundwater aquifer in this area, and can be distinguished into two zones. The upper zone is abrackish water, while the lower one is saline due to salt-water intrusion. The interface between brackish and saline water was distinguished along the interpreted W-E profiles. The geoelectrical succession reveals that aquifer is free type. The saline water intrusion was recoded in both the soundings and the electrical 2-D imaging profiles.
In the area under study, the depth to water increased towards the east, while the salinity of the brackish water decreases towards the east. The thickness of the brackish water zone increases towards the east as well as the depth to the brackish-saline water interface. Drilled wells are more suitable in the eastern parts of the studied area because the depth to water increases in the eastern direction, and the thickness of the brackish water increases towards the eastern direction from 8 m to 47.5 m. The proposed design for each well was tabulated and its safe yield was estimated in the area.