Electrical Assessment of Aquifers in the Basement Complex of Unilorin: Implication for Existing Boreholes

Ojulari, Bashiru Alaba; Saminu OLATUNJI

Electrical Assessment of Aquifers in the Basement Complex of Unilorin: Implication for Existing Boreholes

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Olatunji and Ojulari,2015.pdf(2.17 MB)

Date

2015-08-27

Authors

Ojulari, Bashiru Alaba

Saminu OLATUNJI

Publisher

Journal of Science, Technology, Mathematics and Education (JOSTMED)

Abstract

Schlumberger 4-electrode array was employed to sound 21 stations. IPI2WIN and surfer12 softwares were used to infer lithological series, aquifer thickness and depth. The aquifer hydraulic conductivity K and transmissivity T were calculated from the VES data using the Dar Zarouk principles. The area shows 3 and 4 geo-electric layers from the computer iteration. The layers were interpreted as the topsoil (130- 1469 Ωm), clayey (wet to dry) (52.6- 8552 Ωm), weathered/fractured basement (46.2-249 Ωm) and fresh basement (454-5022 Ωm). The aquiferious zones lie within the second and third layers. The aquifer depth is between 6.17 m and 24.9 m while the thickness range is 1.89-22.7 m. The longitudinal conductance S ranges from 0.02 to 0.468 Ω-1and transmissivity T varies from 246 to 2419.8 Ωm2. The results conformed with the functional boreholes, such as at VES 3, sited in areas with thickest aquifers and highest transmissivity T. The NE and NW parts were found most suitable for fresh water exploitations. Low longitudinal conductance which implies low protective cover, in the vicinity of the borehole near VES6 confirmed the contamination claim of its water.

Citation

1. Olatunji, Saminu and Ojulari, Bashiru Alaba (2015): Electrical Assessment of Aquifers in the Basement Complex of Unilorin: Implication for Existing Boreholes. Journal of Science, Technology, Mathematics and Education (JOSTMED), 11(2). Pages 1-16. ISSN: 0748-4710.