Geoelectric resistivity sounding for delineating salt water intrusion in the Abu Zenima area, west Sinai, Egypt

Abstract

A direct current (dc) resistivity geoelectric technique is applied in the Abu Zenima area, West Sinai, Egypt to delineate salt water intrusion from the Gulf of Suez and evaluate the quality and some of the petrophysical parameters of the aquifer. Sixteen Schlumberger vertical electrical soundings (VES) with maximum AB/2 = 3000 m are conducted. The interpretation of the one-dimensional (1D) inversion of the acquired resistivity data could map the fresh to slightly brackish aquifer (true resistivity = 52-71 ω m, thickness = 17-66 m), which floats on denser, more saline, deeper water (<5 ω m). A number of water samples of the fresh aquifer are analysed to determine the total dissolved solids (TDS) concentrations (ppm). A good agreement is observed between the resistivity boundaries and the borehole data. The mutual relations between the aquifer layering, the direction of the groundwater flow and the hydrogeophysical conditions of the aquifer are investigated. The geoelectric (Dar-Zarrouk) parameters are determined and interpreted in terms of the hydraulic conductivity, transimissivity, clay content, grain size distribution and potentiality of the aquifer. The integration of the results indicates a high potentiality and a relatively good quality of the fresh to slightly brackish aquifer in the north-eastern part of the study area.