ABSTRACT
An investigation was carried out on the groundwater potentials and aquifer protective capacity of Ishiagu area, southeastern Nigeria. The study area lies within the lower Benue trough of Nigeria and is underlain by the Albian Asu River Group and the Turonian Ezeaku Shales.The methodologies employed in the study include measurements of static water levels of 15 hand dug wells, pumping tests carried out on 4 boreholes and vertical electrical sounding (VES) of 20 stations. Groundwater potentials of the area was thoroughly characterizedusing aquifer parameters of hydraulic conductivity and transmissivity within unit cells.These parameters were supplemented with those determined from empirical relationships.The hydraulic conductivity and transmissivity determined from the pumping test data range from 0.6m/day to 3.04m/day and 4.86m2/day to 34.93m2/day respectively while those from empirical relationships range from 0.04m/day to 4.34m/day and 0.07m2/day to 61.69m2/day respectively.Three groundwater potential ratings were defined based on the aquifers’ hydraulic conductivity and transmissivity data; poor (45%), fairly good (35%) and good (20%). The hydraulic head map reveals two divergence and two convergence zones. The computed hydraulic heads range from 58.2m to 84.5m.Vertical electrical sounding reveals that the area is characterized by 4-, 5- and 6- subsurface geo-electric layers with the 6-layer type being the dominant type. Longitudinal unit conductance of the 20 VES stations was estimated from the layers’ resistivity and thickness data.Longitudinal unit conductance of the overburden units ranged from 0.07mhos to 2.22mhos. Based on the estimated longitudinal unit conductance, three aquifer protective capacity types were defined namely, weak (25%), moderate (40%) and good (35%). It was observed that areas of good groundwater potentials also have good aquifer protective capacity. Groundwater development should therefore be concentrated more in areas of good groundwater potential for continuous/steady supply of potable water.
TABLE OF CONTENTS
TABLE OF CONTENT PAGES
TITLE PAGES ii
CERTIFICATIONiii
DEDICATIONiv
ACKNOWLEDGEMENTv
ABSTRACT vi
TABLE OF CONTENT vii
LIST OF TABLES ix
LIST OF FIGURESx
LIST OF APPENDICESxi
CHAPTER ONE: INTRODUCTION
1.1 Background Information 1
1.2 Objectives of the study 2
1.3 Location and Accessibility 2
1.4Drainage, Climate and Vegetation 4
1.5Literature review 4
CHAPTER TWO: GENERAL GEOLOGY AND HYDROGEOLOGY
2.1 Regional Geology 7
2.2 Hydrogeology9
CHAPTER THREE: MATERIALS AND METHODS
3.1 Study materials 12
3.2 Field study method 12
3.3 Field data presentation and interpretation 17
3.4 Data Analysis 17
CHAPTER FOUR: RESULTS AND DUSCUSSION
4.1 Groundwater flow direction 21
4.2 Qualitative results of VES 21
4.3 Quantitative results of VES 27
4.4 Groundwater Potential 34
4.5 Aquifer protective capacity 34
CHAPTER FIVE: CONCLUSIONS
REFERENCES 45
APPENDICES 50
