Reconnaissance of freshwater conditions in a coastal aquifer: synthesis of 1D geoelectric resistivity inversion and geohydrological analysis

Despite the saltwater intrusion of the Gulf of Suez, a Quaternary alluvial aquifer constitutes the main source of freshwater in the coastal city of El-Tor, the administrative capital of South Sinai, Egypt. A conceptual technique synthesizing one-dimension (ID) Schlumberger geoelectric resistivity inversion, geohydrological analysis, borehole data, pumping tests and hydrochemical analysis is conducted to reconnaissance the freshwater aquifer condition in the study area. Aquifer qualitative and quantitative properties in terms of electric and hydraulic conditions were investigated. Furthermore, aquifer loss in relation to a pumping regime was analysed as well. The freshwater aquifer is effectively demarcated with true resistivity and thickness ranges of 71 similar to 110 ohm-in and 22 similar to 83 m, respectively. The eastern part of the freshwater aquifer reveals better conditions characterized by increased values of thickness (83 in), tortuosity (1.306), hydraulic conductivity (53 m/day), transmissivity (4399 m(2)/day), formation resistivity factor (4.4), storativity (0.267) and grain size. Whereas, it characterizes by decreased values of electrical conductivity (1.2 similar to 7.5 mS/m), electric anisotropy (1.08), mean resistivity (285.5 ohm-m), porosity (38.7%) and total dissolved solid (TDS) (530 ppm).