Hydrogeophysical Investigation in Parts of the Eastern DahomeyBasin, Southwestern Nigeria: Implications for Sustainable Groundwater Resources Development and Managemen
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MDPI
Abstract
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Geoelectrical resistivity measurements were conducted in five locations within the eastern
portion of the Dahomey basin for the purpose of subsurface evaluation and detecting saturated
zones. The locations are Covenant University (L1), Bells University (L2), Oju-Ore-Ilogbo Road (L3),
Citation: Oyeyemi, K.D.;
Aizebeokhai, A.P.; Olaojo, A.A.;
Okon, E.E.; Kalu, D.V.; Metwaly, M.
Hydrogeophysical Investigation in
Parts of the Eastern Dahomey Basin,
Southwestern Nigeria: Implications
for Sustainable Groundwater
Resources Development and
Management. Water 2023, 15, 2862.
https://doi.org/10.3390/w15162862
Academic Editors: María del
Carmen Cabrera Santana,
Albert Casas Ponsati and
Alex Sendros
Received: 19 June 2023
Revised: 28 July 2023
Accepted: 30 July 2023
Published: 8 August 2023
Copyright: © 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/).
Obasanjo-Ijagba Road (L4), and Iyana Iyesi (L5). The study was carried out to avert the common
challenges of drilling low-yield groundwater boreholes in the area. A total of 30 Vertical Electrical
Soundings (VES) and five two-dimensional Electrical Resistivity Tomography (ERT) data sets have
been acquired along the study areas. The geoelectrical resistivity results were integrated with the
borehole logs to generate the spatial distribution of the subsurface lithologies in the area. The
delineated subsurface lithologies include the topsoil (lateritic clay), clayey sand, sandy clay, fine silty
sand, coarse sand, and shale/clay units. The fine silty sand and coarse sand units were identified
as the two main aquifer units within the area. The depths to the upper aquifer unit in the area
include 31.7–96.7 m, 38.5–94.0 m, 30.7–57.5 m, 39.1–63.4 m, and 46.9–57.5 m for locations L1, L2, L3,
L4, and L5, respectively. At the same time, the depths to the lower aquifer unit in the area include
43.4–112.7 m, 52.2–108.0 m, 44.2–72.5 m, 53.7–78.5 m, and 63.5–72.9 m for locations L1, L2, L3, L4,
and L5, respectively. The estimated hydraulic parameters for both aquifers show they are highly
productive with mean porosity, mean hydraulic conductivity, and mean transmissivity of 20–22%,
12.4–17.0
10 2 m/s, 1.56–2.18 m2/s for the upper aquifer, and 48–50%, 371–478 10 2 m/s,
50.00–62.14 m2/s for the lower aquifer. By focusing on these aquifer systems during exploration,
sustainable groundwater resources can be secured, providing relief to homeowners within the study
area who might otherwise face the frustration of drilling unproductive and low-yield boreholes.
However, it is crucial to consider the presence of sub-vertical faults in the study area, as these faults
can significantly impact groundwater development and management. These sub-vertical structural
faults may lead to changes in the permeability, hydraulic conductivity, and transmissivity of the
delineated aquifers, affecting their productivity across the divide and ultimately influencing the
overall water availability in the area. Careful consideration of these geological factors is essential for
effective aquifer management and sustainable groundwater utilisation
Keywords
CC Archaeology, GE Environmental Sciences, QC Physics, QE Geology