Geophysical surveys to identify a deep Miocene aquifer in northern Tenth of Ramadan City, Egypt

Groundwater is essential for sustainable development, particularly in dry desert environments like the current research area at the north of Tenth of Ramadan City. The study area suffers from a lack of surface freshwater resources; hence it relies on groundwater as a key source of water supplies needed for agricultural and industrial operations. However, the shallow aquifer is subjected to be contaminated by industrial fluid waste from the nearby un-lined wastewater ponds. This study was conducted to address the deep-seated Miocene aquifer as a source of uncontaminated and sustainable aquifer. This study used two geophysical methods: Audio-magnetotelluric (AMT) with both natural source (NSAMT) and hybrid source transmitter (HSAMT) as the primary tool, and vertical electrical sounding (VES) of DC resistivity data as an auxiliary method to constrain the inversion of AMT data. Based on the 1D-AMT and DC-AMT joint inversion results, the zone of Miocene aquifer exhibits resistivity values ranging from 0.9 to 57.8 Ohm.m at depths ranging from 158.1 m to 267.9 m below the surface. The 2D-AMT inversion results revealed two low resistivity zones; the first (10 to 30 Ohm.m) is presented at a shallow depth (80 to 100 m) and may provide information about the shallow aquifer, while the second (1 to 3 Ohm.m) was obtained at a greater depth (approximately 200 m) and may provide information about a deeper, more saline Miocene aquifer. Furthermore, dimensional analysis of the AMT data reveled that the study area is affected by normal faults striking in E-W direction at the southern part, causing groundwater to leak upwards. Notably, information from nearby groundwater wells was utilized to verify the results of the geophysical data. The findings of the present study will suggest new drilling locations for groundwater production wells in order to deliver more reliable water supplies.