The 2D Electrical Resistivity Imaging (ERI) and Vertical Electrical
Sounding (VES) techniques were deployed for groundwater
extraction at a school located in Oworoshoki, Kosofe, local
government area, Lagos. This becomes necessary due to two failed
existing hand dug wells within the school premises. 2D ERI data and
thirty VES data were acquired along five profiles. The results
revealed four to five geoelectric layers which correspond to the
topsoil, clay, clayey sand, sandy clay and sand. The topsoil is
characterized by resistivity values ranging from 42.5 to 3798.4 Ωm.
The clay has resistivity values ranging from 7.9 to 48.1 Ωm. The
sandy clay has resistivity values ranging from 21.0 to 59.0 m. The
clayey sand in VES (16, 17 and 26) has resistivity values between
72.9 to 96.5 Ωm. The sand identified at the VES (1 to 18 and 22 to
30) has resistivity values of 116.7 to 1531.3 Ωm at the shallow layer
which is suspected to be the seasonal aquifer where most of the
existing hand dug wells were situated. The sand at the fourth to fifth
layer across VES (1, 2, 3, 6, 7, 8, 11, 12 to 15, 18 and 25) with the
resistivity values between 107.2 to 450.0 Ωm represents a good
aquifer where groundwater could be tapped. The 2D resistivity
structures were able to delineate the shallow aquifer thereby
complementing the VES results. Hence, the study recommends that
borehole could be sunk at depth range (39.5 to 90.3 m) in the study
area.