Hydrogeophysical investigation for delineating groundwater aquifers in the Nabaa Al Hammara area, Wadi El Natrun, Egypt

This study integrates geophysical and hydrochemical methods to map and identify freshwater-saturated zones and water quality within the study area. A total of twenty-four Vertical Electrical Sounding (VES) stations were deployed to determine key aquifer parameters, such as thickness and true resistivities. Seven Time Domain Electromagnetic (TEM) stations were also surveyed to corroborate the VES results. Well-logging analysis was conducted in seven boreholes distributed across the study area. Hydrochemical analysis of seven water samples was carried out to assess cations, anions, water type, and water quality ratios. The combined interpretation reveals the presence of three distinct aquifers at varying depths. The first aquifer, located between 60 and 70 m, exhibits resistivity values ranging from 11.5 to 68 Ω-meters and is characterized by freshwater quality. The second aquifer is found at depths of 100–115 m, with resistivities between 6.9 and 52 Ω-meters. The third, or deep aquifer, lies at depths of 180–200 m, with a 155–203 m thickness and resistivity values ranging from 6.5 to 62 Ω-meters. These aquifers show high potential, with a transmissivity (Tp) of 851 m²/day and conductivity values between 13.5 and 14.9 m/day. Hydrochemical analysis reveals that sodium chloride (NaCl) is the dominant water type.