The Ibadan Hydrogeophysics Research Site (IHRS)—An Observatory for Studying Hydrological Heterogeneities in A Crystalline Basement Aquifer in Southwestern Nigeria
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Multidisciplinary Digital Publishing Institute
Abstract
Description
Crystalline basement aquifers are important drinking water sources in Nigeria and several
sub-Saharan African countries. However, an understanding of their local flow and transport pro
cesses and pathways is missing due to limited research. The implication has been their suboptimal
management, with frequently reported dry wells and groundwater contaminations. To address this
challenge, the Ibadan Hydrogeophysics Research Site was established in 2019 as the first field-scale
hydrogeological research laboratory in Nigeria to advance understanding of the geologic, hydraulic,
and hydrogeochemical variabilities within crystalline basement aquifers. The over 22,500 m2 research
site with a 50 m 50 m area used for active hydraulic testing is located within the University of
Ibadan campus and is instrumented with four initial test wells extending through the weathered
and fractured zones to a depth of 30 m each. Preliminary hydrogeological and geophysical studies
focused on obtaining a conceptual model and knowledge of hydraulic heterogeneities to aid in de
Citation: Doro, K.O.; Adegboyega,
C.O.; Aizebeokhai, A.P.; Oladunjoye,
M.A. The Ibadan Hydrogeophysics
Research Site (IHRS)—An
Observatory for Studying
Hydrological Heterogeneities in A
Crystalline Basement Aquifer in
Southwestern Nigeria. Water 2023, 15,
433. https://doi.org/10.3390/
w15030433
Academic Editor: Aizhong Ye
Received: 2 January 2023
Revised: 9 January 2023
Accepted: 18 January 2023
Published: 20 January 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/).
tailed experimental and numerical studies. A combination of lithological logs and electrical resistivity
revealed areas with subvertical fractures as low-resistivity zones (<200 m), and a pumping test
revealed a hydraulic conductivity range of 1.9 10 10 to 7.2 10 6 m/s. Thedrawdown–timecurve
shows flow from single-plane vertical fractures. The results of this study will serve as a basis for
further targeted field and numerical studies for the investigation of variability in groundwater flow
in complex crystalline basement aquifers. The presented field site is posed to support the adaptation
and development of field methods for studying local heterogeneities within these aquifers in Nigeria.
Keywords
GE Environmental Sciences, QC Physics, QE Geology