Assessment of Aquifer Protective Capacity of Groundwater Around Tirwun and Environs, Bauchi State, Northeastern Nigeria

Abstract

An assessment of the aquifer protective capacity of groundwater resources can be
achieved through a variety of geophysical means of investigation. Geoelectric
investigations were conducted around Tirwun and environs in Bauchi State,
Nigeria. Ten (10) vertical electrical soundings (VES) were acquired using an Allied
Omega resistivity meter in northeastern Nigerian Basement rock. By using
geoelectric sections, the subsurface was classified into three (3) layers, namely:
topsoil, weathered zone (clay, sandy-clay, and sand fill fractures), and fresh
basement. The analysis of the materials above the aquifers showed that
longitudinal conductance (S) values ranged from 0.08438 to 0.73449 (mhos).
Hence, classifying the area into weak (0.1 to 0.19), moderate (0.2 to 0.69) and
good protective capacity (>0.7) mhos. Weathered/fractured basement aquifers
were identified as the major aquiferous units in the study area. The aquifers are
characterized by thick-thin overburden with moderate-poor protective capacity,
which also exhibits low transverse unit resistance (on average 763.1046 ohms),
which implies that the materials above the aquifers serve as seals and shield the
aquiferous units. Therefore, areas with weak-poor protective capacity are