Geoelectric investigation for aquifer characterization in Boi and Environs, Bauchi State, Northeast, Nigeria

Abstract

A total of thirty eight (38) Vertical Electrical resistivity Sounding (VES) were used to characterize aquifers in Boi and its environs, Bogoro Area of Bauchi State, Northeastern, Nigeria. The purpose of the study is to characterize the aquifer system in the area using Schlumberger configuration. Because there are multiple failed wells and boreholes in the vicinity, the research is justified. A total of 38 vertical electrical sounding (VES) were carried out, with a maximum electrode spacing of 100 m. The sounding curves acquired were three layer earth models, and the curve types were H, Q, A, and K respectively. The following lithologies were discovered in the area: topsoil with a resistivity of 81ῼm to 264.21ῼm and a thickness of 0.56m to 3.77m, laterite with a resistivity of 526.43ῼm to 999.71ῼm and a thickness of 1.93m to 3.47m, weathered/fracture basement with a resistivity of 10.62ῼm to 238ῼm and a thickness of 2m to infinite depth, and the fresh basement with a resistivity of 1000.33ῼm to 1821ῼm. The longitudinal conductance (S), transverse resistance (T), reflection coefficient (RC), and resistivity contrast (FC) were used to assess the area's groundwater potentials. The area's aquifer protection capacity found to be moderate, weak, and poor, while the groundwater potentials categorized as high, medium, low and very low. According to the results of the evaluated parameters, the area has a predominantly good to moderate groundwater potential. The numerous occurrences of failed/aborted boreholes in the area could be linked to a variety of factors, including poor data quality, lack of technical know-how, incorrect point selection, and poor drilled hole development, all of which are common in Basement Complex terrains. The VES 5 and 10 results showed a dramatic decline in resistivity, indicating that the water likely heavily polluted, particularly by anthropogenic chemicals, or that it was an ancient dumpsite.