Abstract

ABSTRACT
Geophysical survey involving electrical resistivity method has been carried out in Erunmu, Oyo state south-western Nigeria with a view to delineate the geoelectric characteristics of the basement complex and evaluate its ground water potential in the area. A total of 7 vertical electrical sounding stations were established within the site along 7 transverses. The Schlumberger configuration was used for the data acquisition. The half current electrode (AB/2) used range from 1.0 to 75m. The quantitative interpretation of the VES curve involved the use of partial curve matching and the I-D computer iteration technique. The depth sounding interpretation results were used to generate geo-electric sections from which the aquifer was delineated.
The geoelectric section drawn from the result of the interpretation reveals five (5) subsurface layer which comprises of the top soil, latentic sand, partially weathered, weathered and fractured basement. The weathered and fractured constituted the aquoferous zone in all stations.
Hence, from this project work it is recommended that boreholes can be sited in high conductivity zone in VES 1,2,3, and 4 as they contain probable equifers. The depth of any borehole should be located between 15m and 30m to take advantage of the basement fractures.
Keywords: Geo electric, overburden, isoresistivity, latentic, foundation.

Table of Content

TABLE OF CONTENT
Page
Title page i
Certification ii
Dedication iii
Acknowledgement iv-v
Abstract vi
Table of content vii-x
List of Table xi
List of Figure xii
CHAPTER ONE
1.0 Introduction
1.1 General Statement
1.2 Aims and objective
1.3 Location and accessibility
1.4 Relief and drainage
1.5 Climate and vegetation
1.6 Review of previous work.
CHAPTER TWO
2.0 Geological settings
2.1 Regional geology
2.1.1 Basement complex
2.1.2 The younger granite
2.1.3 The sedimentary series
2.1.4 The tertiary recent volcanic rocks
2.1.5 The tertiary recent volcanic rocks
2.2 Climate
2.3 Local geology
2.4 Banded gneiss
2.5 Quartz mica schist
2.6 Granite gneiss
2.7 Pegmatites

CHAPTER THREE
3.0 Research Methodology
3.1 Principle of Resistivity method and electrode arrangement
3.1.1 Wenner Array
3.1.2 Schlumberger array
3.2 Field Techniques
3.2.1 Power source
3.2.2 Meters
3.2.3 Electrodes
3.2.4 Cables
CHAPTER FOUR
4.0 Result and interpretation
4.1 Result
4.2 Interpretation
4.2.1 Qualitative Interpretation
4.2.2 Quantitative Interpretation
4.3 Partial Curve Matching
4.4 Curve Fitting
4.4.1 Interpretation of 4 layer earth by curve matching
4.5 Computer Interpretation
4.6 Result and interpretation
4.6.1 Isoresistivity
4.6.2 Overburden thickness
CHAPTER FIVE
5.0 Discussion
5.1 Conclusion
5.2 Recommendation
REFERENCES
APPENDIX

Introduction

Ground water is a vital natural resources for providing a community’s water supply and play a fundamental role in human well being, as well as that of many aquatic ecosystem and found in basement complex of Nigeria (Ariyo 2003). Ground water occurs in the joint, fractures and fault with contracting permeability (Ako et all 1986).
Ground water is a preferred source in many instances because water quality is generally good as it has been filtered by the soil (Ariyo 2003) (Olorunfemi and Oloromiwo 1985). It is reality available due to its better spahai extension and distribution. This is constantly increasing demand for is resource which as resulted in the tremendous development of the ground water resources during the recent years. Unfortunately, it is not readily available like surface water and it exploitation involves cost and demand a form of technical – know- how.
The early 1900’s brought about development of the electrical resistivity method of deciphering ground water potential (Loehnert 1918, Agbede and Dosumu 1989). Since men, improve technologies have led to a more refined approach to the exploration and exploitation of ground water resource. Appling the resistivity method with the availability of computers for processing and analysing data has greatly helped the matters Reynolds 1997). Many researchers such as Ako et al (1985) and Annoy (2003) have successfully located prolific boreholes using this method.
Different methods of geophysical techniques are used but the well known method that that can be successfully employed for the ground water investigation for rural/ urban area in Nigeria is the electrical resistivity method because of its cost.

Ground Water Exploration Using Resistivity Method In Erunmu And Its Environs, South western Nigeria.

Key Features

Table of Content

Introduction