Applied Journal of Physical Science

The Vertical Electrical Sounding (VES) technique and physicochemical methods were employed to investigate groundwater occurrence within the sedimentary region of Old BB quarters, Wukari in Taraba State, Nigeria. The ABEM 300 SAS Terrameter was used to collect data from ten (10) locations, utilising the Schlumberger array configuration. Data collected was analysed using computer software (Interpex), which yielded an automatic interpretation of apparent resistivity. The VES result revealed a heterogeneous nature of the subsurface geological sequence. The geological sequence has mostly four to five geological layers. The layers inferred are top lateritic soil, clay, weathered sandstone and indurated sandstone. The resistivity value for top lateritic soil ranges from 97.655 to 623.41 Ωm with a thickness of 0.39 to 6.14 m. The second layer recorded resistivity values ranging from 20.436 to 509.11 Ωm with corresponding thicknesses of 2.14 to 27.40 m. The third layer, with resistivity values ranging from 1.03 to 18.73 Ωm and a thickness of 2.80 to 70.54 m, was interpreted as the weathered/fractured layer and consisted of intercalation of sandstone with clay. The layer was suggestive of the aquiferous zone. The resistivity values of the indurate sandstone ranged from 640.33 to 5994.00 Ωm. An iso-resistivity section was generated for AB/2 = 10 m, 60 m and 100 m, electro-stratigraphic section was produced while hydraulic conductivity and transmissivity values were derived from the resistivity data and represented as contoured maps. The maps reveal relatively low resistivity values, implying the presence of clayey materials and/or weathered sandstone. VES stations 4, 6, 9, and 10 were identified as potentially productive. Physicochemical parameters from hand-dug wells showed that temperature, TDS, and EC values exceeded WHO standards, while the anion concentrations were within the acceptable limits prescribed by NSDWQ and WHO. For borehole measurements, the physical parameters complied with recommended levels, although calcium and copper levels in boreholes 2, 3, 4, and 5 surpassed WHO safety limits. All other parameters complied with WHO standards. This has provided information on the depth to groundwater and the thickness of the aquifer unit in the study area.