Investigation of groundwater potential using integrated geophysical methods in Moloko-Asipa, Ogun State, Nigeria

A A Alabi,A F Ogabi,S A Ganiyu,O I Popoola,O A Idowu

doi:10.1007/s13201-021-01388-3

Abstract

Water is essential for livelihood, development, and industrial growth. Its exploration in sufficient quantity is required where it does not freely occur on the surface. This research was aimed to delineate aquifer regions and provide information on the subsurface lithology of Moloko-Asipa Southwestern Nigeria. A combination of eight traverses investigated with very low frequency electromagnetic (VLF-EM) method at 5 m constant sampling interval and ten vertical electrical sounding (VES) were carried out in the survey. Measurements from the VLF-EM survey were processed with Karous and Hjelt filtering to give the resistivity contrast across the selected profiles. The VES data processing involved an automatic approximation of the initial resistivity and thickness of the geoelectric layers with IPI2Win and further filtering by WinResist iteration. Estimation of Dar-Zarrouk parameters was also employed to investigate the aquifer protective capacity of the area. The processed VLF-EM results showed the geology of the area to an average depth of 25 m. The geoelectric section of the VES data revealed minimum of 3 layers from sandy top soil to weathered layer and fresh basement with an average resistivity values of 1,816, 926 and 17,503 Ωm, respectively. The integration of VLF-EM and VES in the investigation revealed that the potential for groundwater exploration in the study area is poor due to the thin nature of the weathered layer and its shallow depth to basement. The aquifer protective capacity of the area was likewise inferred to be poor.

Highlights

The study of groundwater exploration is increasing in recent times due to its inevitable needs for livelihood, development and industrial growth
The very low frequency electromagnetic (VLF-EM) profiling was carried out on eight traverses and the results revealed the points which are relatively conductive with depth
Very low frequency electromagnetic (VLF-EM) profiling and vertical electrical sounding methods were employed in the survey

Summary

Introduction

The study of groundwater exploration is increasing in recent times due to its inevitable needs for livelihood, development and industrial growth. Groundwater plays a vital role as it is a dependable primary source of freshwater for all needs in areas where surface water is inadequate or not available (WWDR 2015). The field source that is required to generate information about an object of interest in the subsurface can either be artificial or natural (Henderson 1992). A filtering process is needed to eliminate the field signals from all other sources to get the specific signal that will characterize the target (Janvier et al 2015). One advantage of natural field source is that it does not require any additional deployment to generate the field, unlike the artificial source where a further deployment is needed. With the view of characterizing the subsurface lithology, identifying structures that would reveal information on the potential for groundwater exploration in the area is a goal

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Conclusion