Groundwater Deductions from Geoelectric Survey in Burutu Island, Delta State, Nigeria

Omamode S Marere,Christopher O Ohwona,Kennedy O Ojo

doi:10.19026/rjees.6.5758

Abstract

A resistivity survey was carried out in order to study the groundwater conditions in Burutu Island, the thickness, depth, location of aquifer and type of aquifer were determined utilizing the surface Schlumberger electrode array with maximum current electrode spacing of 300 m. A total of 4 VES stations were sounded and seven geoelectric layers were delineated in the survey area. The first layer was top soil with resistivity values ranging from (54-893 &Omegam) and thickness between (0.5-1.4 m). The second layer had a resistivity ranging from (24.82-2768.0 &Omegam) and thickness of (2.03-3.71 m) consisting of fine to medium sand. The third to fifth geoelectric layers consist of sandy clay sand with thickness varying from (3.12-17.23 m) and resistivity values of (1.21-163.91&Omegam) which indicates saline intruded water zone. The results of the VES interpretation shows that a good source of aquifer was encountered at a depth of 49 m with a thickness of 19m which extends into the seventh layer. The results of the resistivity survey revealed that the parameters obtained through the interpretation of the VES curve using Win Resist software corresponds to the litholog of the borehole close to VES 4.

Highlights

Increase in population and urbanization on a daily basis in the coastline of Niger delta areas of Nigeria have led to a corresponding reduction in quality of groundwater in these areas
Typical curve types exemplary of saline water intruded zones were observed in all the Vertical Electric Sounding (VES) points such as QQ and KQ
All the curves descended gently indicating that there was conductivity decrease which shows saline water intrusion into subsurface formations (Fig. 2 and 3). These descending segments of the VES curves are characteristic of low resistivity zones (Fig. 2 and 3)

Summary

Introduction

Increase in population and urbanization on a daily basis in the coastline of Niger delta areas of Nigeria have led to a corresponding reduction in quality of groundwater in these areas. If the groundwater withdrawal in coastal environments is not sufficiently controlled, it can lead to seawater intrusion, degradation of aquifer quality as a result of infiltration rate and up-coning of the saline water layer at the saltwater-freshwater interface (Oteri, 1988). In view of the above, the Vertical Electric Sounding (VES) technique was used in the present study to investigate groundwater potential in Burutu Island, Burutu local government area of Delta State, Southern Nigeria such as freshwater and saltwater as well as depth to freshwater-saltwater interface.

Results

Conclusion