Geoelectrical Characterization of Coastal Aquifers in Agbado-Ijaye, Lagos, Southwestern Nigeria; Implications for Groundwater Resources Sustainability

Oyeyemi, Kehinde D. and Abuka-Joshua, Joyce and Rotimi, Oluwatosin J. and Dieppois, Bastien and Gomo, Modreck and Olaojo, A. A. and Falae, Philips O. and Metwaly, Mohamed (2023) Geoelectrical Characterization of Coastal Aquifers in Agbado-Ijaye, Lagos, Southwestern Nigeria; Implications for Groundwater Resources Sustainability. Sustainability,. ISSN 2071-1050

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Abstract

Water is a natural resource; its availability depends on climatic and geological conditions, and it is invariably controlled by human activities. Agbado-Ijaye lies within a coastal area, where local communities have been facing incessant water shortages, especially during the dry season. This study investigated the groundwater-bearing geological 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 electrical resistivity imaging traverses having a length of 200 m each and interelectrode 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.

Item Type:	Article
Uncontrolled Keywords:	geoelectrical resistivity surveys; groundwater resources; coastal aquifer; Lagos; Nigeria
Subjects:	Q Science > Q Science (General) Q Science > QC Physics
Divisions:	Faculty of Engineering, Science and Mathematics > School of Physics
Depositing User:	AKINWUMI
Date Deposited:	24 May 2023 11:24
Last Modified:	24 May 2023 11:24
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/16920

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