Investigating the less ambiguous hydrogeophysical method in exploring the shallow coastal stratified-saline aquifer: a case study at West Port Said Coast, Egypt

Abstract

Recently, groundwater resources of the coastal aquifers attract the attention of arid countries such as Egypt. West Port Said coast is one of those areas, which is depending on groundwater for urban and industrial expansions. Usually, groundwater exploration in such coastal areas is considered as one of the most difficult challenges due to its highly conductive substrata and seawater intrusion. Thus, the main objective of this research is determining the best hydro-geophysical method, which shows the high accuracy results with less ambiguity in exploring the coastal aquifer in the west Port Said coastal study area, which was a part of Manzala Lagoon as inferred from the processed satellite images. Meanwhile, the vertical electrical sounding (VES) and transient electromagnetic (TEM) have become the most popular hydro-geophysical techniques, which are widely used to explore and locate groundwater resources. In this study, a total of five VES and eight TEM soundings were carried out and correlated with the nearby drilled wells. The results showed that the electrical current of the VES method cannot penetrate deeper than 10 m due to the presence of saline materials that obscured the current to pass through and cannot distinguish clearly between the subsurface conductive layers and suffers from high ambiguity. While the TEM method has provided fast, relatively accurate results, deeper (300-m depth) and has the ability to distinguish clearly between the subsurface conductive layers compared with VES technique. Consequently, the TEM method showed many comparable and less ambiguous results to the drilled wells and suitable for such coastal environments.