Pre-Drilling Geoelectrical Survey at a Built-up Compound at Barkin-Sale Ward, Minna, Niger State, Nigeria

Abstract

The three corners of a brick fence enclosing a bungalow away from the corner where a cesspool was situated, defined in one north-south (longitudinal traverse, LT) and two east-west (transverse traverse, TT) modes, was selected for this survey. A four-layer sequence was identified for VES TT1, a four-layer sequence for VES LT1, and a three-layer sequence for VES TT2. The authors based their interpretation for aquifer prospect at the three VES locations on a combination of informal and fairly successful dual empirical rules to determine the likely presence of groundwater in the basement complex geological province. Based on these rules, TT1 indicates the best prospect for groundwater yield in the area of survey with good showings from the 30m-depth mark down to the 50m-depth. Also, it is observed that the 50m depth mark for TT1 and TT2 correlate very well as a prospective aquifer zone. If drilling must be done at all, then it is recommended that point TT1 be considered a good prospect for groundwater yield over the 20-m “yield window.” Because of the smoothly-changing continuum of resistivity values down to the 100m-depth mark, drilling should be terminated at this maximum or total depth (TD) of survey in order to tap into the fractured basement at this TD. Incidentally, TT1 is upslope of the sewer pit, which is a plus for this VES station over the possible prospect of TT2.