Water is a natural resource, its availability depends on climatic and geologic conditions, and is invariably controlled by human activities. AgbadoIjaye lies within the coastal area, where local communities have been facing incessant water shortages, especially during the dry season. This study investigated the groundwater-bearing geologic unit(s) using hydrogeophysical techniques in the coastal environment. The electrical resistivity technique, involving Vertical Electrical Sounding (VES) and two-dimensional (2D) electrical resistivity imaging via Wenner array electrode configuration, was used to characterize the geoelectric distribution. Twenty VES stations were investigated, and current electrodes (AB/2 m) spacing expanded from 1-200 m; four 2D tomographies having a length of 200 m each and inter-electrode spacing of 10 m (level 1) to 60 m (level 6) was adopted. Four geoelectric units were delineated namely: topsoil (15-251 Ωm), clayey (28-100 Ωm), clayey sand (125-190 Ωm) and sandy (205-876 Ωm) with thicknesses ranging from 0.7-1.3 m, 4.1-19.0 m, 2.6-15.6 m and undefined depth, respectively. The 2D imaging sections also detected similar geoelectric layers corroborating the VES-derived sections. The inverted sections delineated two different aquifers: the shallower low-yield aquifer comprising sandy clay/clayey sand units with a maximum depth of about 5.5 m. This layer is adjudged to be the continental plain sand of the Benin Formation. The deeper high-yield aquifer with a maximum depth of 30.4 m, is a beach sand unit that belongs to the Tertiary Alluvium of the Dahomey Basin. The study showed that hydrogeophysical investigation is vital in exploring, developing, and managing coastal groundwater resources.
|Number of pages||22|
|Early online date||14 Feb 2023|
|Publication status||Published - 14 Feb 2023|
Bibliographical note© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
FunderThis work was funded by the Research Supporting Project number (RSP2023R89), King Saud University, Riyadh, Saudi Arabia
- Geoelectrica resistivity surveys
- groundwater resources
- coastal aquifer