Geophysical Investigation of Groundwater Potential using Dar Zarook Parameters in shallow aquifers of Northeastern part of Osogbo, Nigeria

The groundwater potential and aquifer protective capacity in the Kasmo Area of Osogbo were investigated using the Dar Zaroouk approach via the Schlumberger technique of electrical resistivity method. Five vertical electrical soundings (VES) points were occupied and surveyed using the ABEM SAS 1000 terrameter. The field data were first interpreted using the partial curve matching and later iterated using the WinResist software. The resistivities and thicknesses of the geoelectric layers were used to compute the longitudinal conductance and transverse resistance. These were later used to compute the hydraulic conductivity and transmittivity of the aquifers. Three to five geo-electric layers aquifer layers show a confined to semi-confined configuration with the aquiferous layer occupying the second, third and fourth layers. The resistivities vary from 66.5 Ωm in VES 4 to 141.9 Ωm in VES 3. The longitudinal conductance also varies between 0.0366 Ω-1 in VES 3 to 0.0074 Ω-1 in VES 1 while the transverse resistance varies between 34.8 Ωm2 in VES 3 to 1043.8 Ωm2 in VES 5. The transmittivity values were observed to range from 20736.10 m2/day in VES 3 to 287787.81 m2/day in VES 4, the aquifers possess high groundwater potential with transmittivity values far above the Offodile classification of aquifer potential limit of 500 m2/day. The investigation concluded that aquifer potential determination through the estimation of Dar Zarook parameters gives a better aquifer potential determination than the conventional resistivity method, as the method compares the potential of all points at once. Keywords: Aquifer, Kasmo, Longitudinal, Resistance, Resistivity, Transverse