PAPER TITLE :A GEOELECTRIC INVESTIGATION OF THE GROUNDWATER POTENTIAL IN A BASEMENT COMPLEX TERRAIN OF SOUTHWESTERN NIGERIA.

JOURNAL OF EARTH AND ATMOSPHERIC RESEARCH | VOLUME 1 NUMBER 1 2018

Paper Details

  • Author(s) : Bayode, S.
  • Abstract:

A geoelectric investigation of the groundwater potential of the basement complex underlain Ire – Akari Estate
in Orita Obele, Akure, Southwestern Nigeria, was carried out. The electrical resistivity survey involved the
Vertical Electrical Sounding (VES) technique. Ninety six (96) VES were conducted and quantitatively
interpreted. The geoelectric sections revealed subsurface geologic units consisting of the topsoil, laterite,
weathered layer, partly weathered/fractured basement and the fresh basement bedrock. The layer resistivity
values are respectively 24 – 567 ohm-m, 77 – 617 ohm-m, 23 – 222 ohm-m, 338 – 714 ohm-m and 300 – ∞
ohm-m while the thicknesses are 0.4 – 2.6 m, 1.8 – 17.6 m, 2.5 – 36.0, and 4.8 – 35.0 m respectively. The depth
to basement bedrock ranged from 5.4 – 37.7 m. The topsoil generally is clayey with resistivity values that are
< 100 ohm-m and low permeability and low groundwater recharge infiltration characteristics. The weathered
layer, main aquifer unit, for most parts of the study area has resistivity values of < 150 ohm-m that are typical
of clay/sandy clay which also exhibit low permeability and tendency for low groundwater yielding capacity.
The overburden is generally thin < 20 m in most parts of the estate with low groundwater storage capacity.
This study concludes that the groundwater potential of the estate is adjudged to be generally low. However,
there are isolated locations with identified basement fractures whose groundwater potential could be of
moderate level rating.

JOURNAL OF EARTH AND ATMOSPHERIC RESEARCH