APPLICATION OF GEOELECTRICAL RESISTIVITY IMAGING TO INVESTIGATE GROUNDWATER POTENTIAL

Project TopicsAPPLICATION OF GEOELECTRICAL RESISTIVITY IMAGING TO INVESTIGATE GROUNDWATER POTENTIAL ABSTRACT Geoelectrical resistivity imaging using both 2D and Vertical Electrical Sounding (1D) method was carried out in Atan , Ado/Odo Ota Local Government, Ogun State ,Nigeria using the PAS earth resistivity meter.Three profiles was carried out using both Wenner and Schlumberger array configuration. The data was interpreted using RES2DINV for 2D and computer iteration method (WinResist) for VES. Results showed that there are five major layers which described the geological structure of the study area. The resistivity values ranges between 1200Ωm to 4000Ωm,500Ωm to 1000Ωm, 400Ωm to 800Ωm , 200Ωm to 400Ωm and 60.7 Ωm to approximately 100Ωm respectively according to the structures. VES1,VES 2, VES 3 and VES 4 apparent resistivity curve shows the different layers with their corresponding thicknesses. The study area revealed that the depth to the aquifer ranges between 130m t0 140m.TABLE OF CONTENTSCertification iiDedication iiiAcknowledgements iv-vList of Tables viiiList of Figures viii -ixAbstracts xCHAPTER ONE1.1 Introduction 1 – 31.2 Geological Description of Underground Water 3 – 41.2.1 Occurrence of Groundwater 41.2.2 The movement of Groundwater 5 – 61.2.3 Transmission of Groundwater 6 – 81.2.4 Recharge 81.2.5 Leakage 8 – 91.2.6 Withdrawal 91.2.7 Aquifers 9- 111.3 Location of the study area 121.4 Aim and Objectives 141.5 Scope of the Study 141.6 Justification of the study 14CHAPTER TWO2.1 Literature Review and Geological Setting 15-212.2 Geological Setting of the study area. 21-22CHAPTER THREE3.1 Electrical Resistivity Theory and Methodology 233.1.1 Single Current Electrode at Depth 243.1.2 Single Current Electrode at Surface 253.1.3 Two Current Electrode at the Surface 253.2 Apparent Resistivity and Electrode Configuration 25 ” 263.3 Resistivity Survey 27 – 283.4 Field Measurement Procedure 28- 303.5 The Field Work Procedure 30-34CHAPTER FOUR4.1 Results and Interpretation 35-364.2 Data Collected for Profile 1 37-404.3 Data Collected for Profile 2 41-444.4 Data Collected for Profile 3 44CHAPTER FIVE5.1 Result, Discussion, Conclusion and Recommendation 455.1.1 Profile 1 Discussion 45-475.1.2 Profile 2 Discussion 48-505.1.3 Profile 3 Discussion 51-535.2 Conclusion 545.3 Recommendation 54-555.4 Contribution to Knowledge 55References 56-61APPENDIXLIST OF TABLESTable 4.1: Raw Data for 2D in Profile 1 37Table 4.2: Raw Data for 2D in Profile 1 38Table 4.3: Raw Data for 2D in Profile 1 38Table 4.4: Raw Data for 2D in Profile 1 39Table 4.5: Raw Data for 2D in Profilr 1 39Table 4.6: Raw Data for 2D in Profile 1 39Table 4.7: Raw Data for 2D in Profile 1 40Table 4.8: Raw Data for 2D in Profile 1 40Table 4.9: Raw Data for 2D in Profile 1 40Table 4.10: Raw Data for 2D in Profile 1 40Table 4.11: Raw Data for 2D in Profile 2 41Table 4.12: Raw Data for 2D in Profile 2 42Table 4.13: Raw Data for 2D in Profile 2 42Table 4.14: Raw Data for 2D in Profile 2 43Table 4.15: Raw Data for 2D in Profile 2 43Table 4.16: RawData for 2D in Profile 2 44Table 4.17: Raw Data for VES in Profile 3 44LIST OF FIGURESFigure 1.1: Approximation of time varying infiltration rate 8Figure 1.2: Sketch diagram of (a) homogeneous (b) Inhomogeneous (C) Anistropy aquifers 9Figure 1.3: Hydrological cycle and aquifers type 11Figure 1.4: Base map of the study area 12Figure 1.5: Geological map of Ogun State showing the study area 13Figure 3.1: A conventional four electrode array to measure the subsurface Resistivity 27Figure 3.2: Common arrays used in resistivity surveys and their geometric factors (Loke, M.H 1997; 1999) 28Figure 3.3: 2D measurement Using Wenner Arrangement Configuration (Loke, 1999) 30Figure 3.4: Schlumberger Array Configuration 32Figure 4.1: Showing the PAS Earth Resistivity Meter used for Data Aquistion 40Figure 5.1: Showing the measured data of the study area for profile 1 46Figure 5.2: Showing the measured apparent resistivity, calculated  apparent resistivity and inverse model resistivity section for profile 1 of the study area 47Figure 5.3: Showing the field work survey in progress 48Figure 5.4: Showing the measured data of the study area for profile 2 49Figure 5.5: Showing the measured apparent resistivity, calculated apparent resistivity and inverse model resistivity section for profile 2 of the study area 50Figure 5.6: Showing typical curve for VES 1 51Figure 5.7: Showing typical curve for VES 2 51Figure 5.8: Showing typical curve for VES 3 52Figure 5.9: Showing typical curve for VES 4 52