Hydro-sedimentological Evaluation of Aquifer Properties In Parts of Southern Anambra Basin.
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Date
2025
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Journal ISSN
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Publisher
Faculty of Applied Sciences, Ibrahim Badamasi Babangida University, Lapai, Niger State, Nigeria.
Abstract
Nigeria's cities lack potable water supply system, due to failed water supply system,
leading to groundwater reliance.
Understanding hydrogeological settings of some basins like
Anambra Basin is tough due to its complex geological heterogeneity and varying
sedimentary structures. The commonly used electrical resistivity method has ambiguity
issues because it often struggles to distinguish between different lithological units with
similar resistivity values, leading to misinterpretation of subsurface geology. The alternative
hydro-sedimentological approach estimates aquifer properties from grain size. In this study,
twenty-five (25) sand samples were collected from boreholes cuttings; this is because sands
are the primary aquifer-hosting materials in southern Anambra Basin. Ten empirical
relationships were used to estimate hydraulic conductivities from the grain size data.
Porosity, specific yield (SY), and specific retention (SR) were also empirically determined.
Pumping data were available for ten (10) locations. For the remaining fifteen (15) locations,
where pumping tests were not conducted, permeameter tests were performed on well cuttings
to estimate hydraulic conductivity. The graphic mean of the sands ranges from 0.071 to
1.533phi, indicating that the sands are mainly medium-sized. Fractional porosity values,
Specific yield and Specific retention range from 0.260 to 0.392, 0.274 to 0.039, and 0.125 to
0.322, respectively. Hydraulic conductivity ranges estimated from Hazen Simplified,
Slichter, Terzaghi, Beyer, Sauerbrei, USBR, Barr, Alyamani & Sen, Chapuis, and Uma
models are between 1.31-22.37m/day, 0.31-6.85m/day, 0.5-12m/day, 1.4-19m/day, 1.22-
16.71m/day, 1.42-13.37m/day, 0.36-9.3m/day, 0.01-8.72m/day, 0.17-11.3m/day, and 0.02-
10.64m/day respectively. Hydraulic conductivity obtained from pumping test ranges from
0.89 to 7.06m/day, while the values are 0.0864 to 25.488m/day from permeameter test,
classifying the aquifers as having medium to high groundwater potential according to
Terzaghi, Barr, Chapius and Uma estimates. In conclusion, this study was able to map out the
groundwater potential of the area and revealed the most suitable empirical relation for
estimating groundwater potentials within the area.
Description
Keywords
Specific yield, Specific retention, Hydraulic conductivity.
Citation
. Iheme, K. O., Obaro, R. I., Abubakar, H. O., Omotoso, O. A., Ibrahim, K. O., Olelewe, M. C., & Magbo, J. C. (2025): Hydro-sedimentological Evaluation of Aquifer Properties In Parts of Southern Anambra Basin. Lapai Journal of Science and Technology. 11(1); 36-58