Groundwater exploration using drainage pattern and geophysical data: a case study from Wadi Qena, Egypt

Abstract

In the Wadi Qena region, the digital elevation model (DEM), aeromagnetic, and magnetotelluric data are processed and examined to outline surface water flow patterns, the subsurface structures, demonstrate their effects on the groundwater flow direction, and assess the groundwater aquifer thickness and the relationship between subsurface structures and the inherited surface water flow (drainage pattern). Wadi Qena’s drainage pattern and watershed basins were delineated using satellite digital elevation data in order to accomplish these objectives. The first vertical derivative transformation was used and examined to determine the prevailing northwest-southeast and northeast-southwest structural trends impacting the region. In order to handle aeromagnetic data, it is necessary first to reduce the observed magnetic data such that they correspond to the reduced magnetic pole (RTP). The two-dimensional analytical signal technique was used to discover that the depth of the basement rocks, which in the research region serve as the bedrock of the overlying groundwater aquifer, ranges from 101 to − 1165 m relative to sea level. This information was obtained by measuring the distance from the earth’s surface to the bedrock. To further define the accurate subsurface geological model in the region, the conducted magnetotelluric survey in the area was interpreted using the 1-D inversion technique, and the results were coupled with the existing drill data. The base of the groundwater aquifer was discovered to be between 350 and 410 m deep. Finally, the results are reliable and closely related to earlier geological and geophysical investigations in the studied area.