Aquifer Mapping Using Joint Inversion of VES-TEM Data in the Semiarid West Ismailia Area, Egypt

Joint inversion of different geophysical data sets has demonstrated its effectiveness in mitigating the limitations associated with individual methods and maximizing their respective advantages. This study investigates the groundwater aquifers in the western area of Ismailia city, Egypt, which faces water scarcity and relies heavily on groundwater. Vertical Electrical Sounding (VES) and Transient Electromagnetic (TEM) data were collected at 35 points along five parallel profiles to assess the primary aquifers in this region. These data sets, gathered at nearly identical locations, were inverted separately before performing joint inversion to enable objective comparison. The joint inversion, conducted using the Curupira Program, revealed two aquifer systems in the Pleistocene and Miocene units. The Pleistocene aquifer, identified as the primary aquifer, consists of gravel, sand, and clay lenses with depths ranging from 10 to 83 m and thicknesses from 129 to 236 m. Its resistivity ranges from 4 to 95 Ωm. The Miocene aquifer is underlying the Pleistocene aquifer at depths between 130 and 291 m and primarily consists of marine marly sandstone and limestone, with resistivity values of 6 to 22 Ωm, indicating predominantly saline groundwater. Overall, this study provides valuable insights into the hydrogeological characterization of the study area and highlights the potential and limitations of joint inversion techniques in the accurate assessment of aquifer systems.