The Ibadan Hydrogeophysics Research Site (IHRS)—An Observatory for Studying Hydrological Heterogeneities in A Crystalline Basement Aquifer in Southwestern Nigeria

Doro, Kennedy O. and Adegboyega, Christianah O and Aizebeokhai, A. P. and Oladunjoye, M.A (2023) The Ibadan Hydrogeophysics Research Site (IHRS)—An Observatory for Studying Hydrological Heterogeneities in A Crystalline Basement Aquifer in Southwestern Nigeria. Water, 15 (433).

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Abstract

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.

Item Type:	Article
Uncontrolled Keywords:	crystalline basement aquifers; groundwater; geophysics; southwestern Nigeria
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QC Physics Q Science > QE Geology
Divisions:	Faculty of Engineering, Science and Mathematics > School of Physics
Depositing User:	ORIGBOEYEGHA
Date Deposited:	07 Aug 2024 08:06
Last Modified:	07 Aug 2024 08:06
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/18367

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