User:IDIATA2/sandbox

<!--      A                     TECHNICAL REPORT ON              STUDENT INDUSTRIAL WORK EXPERIENCE SCHEME (SIWES) AT EDO STATE URBAN WATER BOARD BENIN CITY BY                     OKORUWA PETER MATRICULATION NUMBER:- FNS/PHY/15/19243 SUBMITTED TO        FACULTY OF PHYSICAL SCIENCES, DEPARTMENT OF PHYSICS (GEOPHYSICS OPTION) AMBROSE ALLI UNIVERSITY, P.M.B 14, EKPOMA, EDO STATE NOVEMBER 2017.

CERTIFICATION This is to certify that OKORUWA PETER a student of Geophysics, Faculty of Physical Sciences, Ambrose Alli University, Ekpoma carried out a six months industrial attachment in the Edo State Urban Water Board, Benin City.

MR. K.O. OZEGIN							        DATE I.T CO-ORDINATOR (PHYSICS)

DR. O.J ATAMAH							      DATE HEAD OF DEPARTMENT (PHYSICS)

DEDICATION I dedicate this report to God Almighty for his unfailingly love, strength, kindness and mercies and his unlimited protections and provision and also to my parents for their constant prayers, encouragements, and provision during my time in Edo State Urban Water Board, Benin City.

ACKNOWLEDGMENT My profound appreciation goes to Almighty God the giver of life for his protection and provision. I wish to thank the management of the Edo State Urban Water Board for granting me placement in their reputable company. My gratitude to my supervisor (HOD) water resources Mr. Wellington Edokpayi, Mr. Michael Ehana, Mr. Liberty Egbobamien and Engr. Mr. Oseki. I am so grateful to the staffs and students on Ambrose Alli University. My profound gratitude also goes to my head of department (HOD) Physics, Dr. O.J Ataman and all physics and geophysics lecturers who contributed to the success of this program. I will not fail to recognize my fellow explorers who have in one way or the other also supported me. Finally, my profound gratitude to my lovely and caring parents for their undying love, care, prayers and supports throughout my training.

ABSTRACT This training was actually a great experience and academic consolidation practicing what had been taught theoretically in class. During my industrial attachment at Edo State Urban Water Board with the development of water resources. This six months industrial training placement which is tandem requirement for the honor of Bachelor of Science in the Geophysics profession, started on the 12th of June, 2017. During the period of this industrial training, at first, I was introduced to my supervisor Mr. Oseki and the department (water resources). I was taught both in class and on the field during the period and topics such as Underground water, geophysical survey etc. and the equipment use in their operation was broadly treated. The industrial training was interesting, educative and practically oriented.

TABLE OF CONTENT CERTIFICATION…………………………………………………………………….. DEDICATION…………………………………………………………………………. ACKNOWLEDGEMENT…………………………………………………………….. ABSTRACT…………………………………………………………………………….. TABLE OF CONTENT………………………………………………………………...

CHAPTER ONE Introduction……………………………………………………………………….. Historical development of SIWES…………………..…………………………… Aim and objectives of SIWES……………………………………………………. The scope of the scheme………….………………………………………………... Contribution of the scheme………………………………………………………… Problems affecting the scheme………………….………………………................. Introduction about the board……………………………………………………… Brief history of the board…………………………...………………………… Aims and objectives of the board………………………………………………… Geology of Edo state province………………………….. Department within the board………………………………………… Aims and objective of the training………………………………….………………………… Organogram for Edo state water board………………………………………………………. CHAPTER TWO Ground water……………………………………………………………………… Water infiltration………………………………………………………………………….. Ground water movement and distribution………………………………………………. Aquifer-water bearing rock unit…………………………………………………………. Fluctuation of water table………………………………………………………………….. CHAPTER THREE Ground water quality……………………………………………………………………….. Anthropogenic activities…………………………………………………………………….. Natural process………………………………………………………………………………. CHAPTER FOUR Geophysical survey…………………………………………………………………………… Types of geophysical survey…………………………………………………………………. Importance of VES in ground water exploration…………………………………………… Factors affecting conductivity of earth material……………………………………………. A case study of geophysical investigation……………………………………………………. CHAPTER FIVE Borehole drilling………………………………………………………………………………. Terms use in borehole………………………………………………………………………… Method of borehole construction………………………………………………………………. Material / method required for borehole drilling……………………………………………. CHAPTER SIX Conclusion / Recommendation………………………………………………………………… References …………………………………………………………………………………….

CHAPTER ONE 1.0	 INTRODUCTION This technique report is a concise documentation of my exposure and experience gained in the area of geophysical survey during my Industrial work experience scheme (SIWES). The program started on May and ended in October, in partial fulfilment of the award of Bachelor of Science (B.Sc.) in Geophysics,

1.1	HISTORICAL DEVELOPEMENT OF SIWES The students industrial work scheme (SIWES) came into establishment of the Industrial Training Fund (ITF) under degree No 47 of 8th October 1971, in a bid to boost indigenous capacity for the nation’s industrial need, the fund in its policy statement No. 1 published in 1973 inserted a clause dealing with the issue of practical skills which states that “the seek will week to work out cooperative machinery with industry where students in institution of higher learning may acquire training in industry or mid-career attached by contributing to the allowance payable to the students”

1.2	AIM AND OBJECTIVES OF SIWES 	To provide students with an opportunity to applied their theoretical knowledge in real work situation thereby bridging the gap between theories and practical. 	To provide avenue for students in institution of higher learning to acquire industrial skills and experience in their course of study while in school. 	To expose students to work method and techniques in handling equipments and machineries that may not be available in some educational system. 	To enhance and strengthened employers involvement in the educational process and preparing student for employment in the industries.

1.3	THE SCOPE OF THE SCHEME The scope of the program varies from on department to other. The students in Physics departments, AAU observes this program in 300L second semester for a period of six months. This is observed by all institution of higher learning offering Geophysics and related disciplines. The scheme therefore is pre-requisite to graduating students from institution of higher learning most especially geophysical resources related courses like Geophysics, Mining, Engineering Geology, Petroleum Geology, Applied Geology etc. Its copes revolve around practical experience on site.

1.4	CONTRIBUTION OF THE SCHEME The scheme is making a tremendous impact in the economy and technological development of the country especially on human resources development. An elaborated summary of some of the contribution of the scheme re as follows; I.	It offers the students an opportunity to associate themselves with workers at their various levels in the industries. II. It has contributed to the improved quality of skilled man-power in Nigeria. III. It prepares the students so that they can fit into employments in the industries IV. It creates more relationship between institution and industries.

1.5	PROBLEMS AFFECTING THE SCHEME SIWES has encountered a lot of problem in recent times, and this has affected its growth and development. Below are some of the problems; 	There is inadequate funding system which reduces the student capability at work since they are not well motivated. 	Supervision sometimes are not carried out as scheduled due to inadequate funding which makes students unserious and relax to work. 	Employers hardly have time to impact knowledge to the students.

1.6    INTRODUCTI ON ABOUT THE BOARD The Edo State Urban Water Board is a Government parastatal that deals mainly with the exploration of ground and surface water using geological equipment for the production of portable water for the public and industrial needs. This involves all aspect of water including sourcing, storage, treatment and distribution of water for the consumers. The Edo State Urban Water Board has the responsibility of providing portable water to the urban and semi urban areas of the state. The board has been carrying out this responsibility with the few numbers of Dams and pumping station spread across the 18 local Government areas of the state. Optimal performance by the Board across 18 local Government Areas of the State has however been hampered by lack of adequate manpower, ageing equipment and poor maintenance. The board has about 63 pumping stations ( including dams ) spread across the state. 1.7     BRIEF HISTORY OF EDO STATE URBAN WATER BOARD The Edo State Urban Water Board was originated from the Bendel State of Nigeria Water Board Edict NO. 27 of 1969 in the year 1994 on the 12th of September. The Board which is parastatal of Edo State Government is under the supervision of the deputy governor`s office. The Board which is Head office is located at Sapele Road, Benin City Edo State provides social services and is a non-profitable organization. 1.8      AIMS AND OBJECTIVE OF EDO STATE URBAN WATER BOARD •	To provide portable water for the citizens of the state, both rural and urban. •	To serve as a source of employment for the citizens of the state in particular and the country in general. •	To be a source of revenue collection for the Government of the state. 1.9    FUNCTIONS OF VARIOUS DEPARTMENTS IN EDO STATE URBAN WATER BOARD. •	DEPARTMENT OF ADMINISTRATION This department is in charge of general administration, legal and public relations matters. AUDIT DEPARTMENT It ensures that all financial transactions in the board follow due rules and procedure. •	DEPARTMENT OF ACCOUNTS The department comprises the main accounts section that keeps all financial records, the department that is responsible for all salary related matters and the store sections that is in charge of receiving purchases and issuing same after necessary approval have been obtained. •	MARKETING DEPARTMENT The department is in charge of distribution of bills to the consumers, disconnection of debtor’s consumer services and reconnection of same. •	COMMERCIAL / BILLING DEPARTMENT The department is in charge of raising bills (quarterly) and passing same to the marketing department for distribution. The department also enters payment by water consumers and maintains a record of consumers. •	OPERATIONS DEPARTMENT The department is responsible for the maintenance of motorized and stationary equipment. The department is also in charge of generation and distribution of water. •	WATER RESOURCES DEPARTMENT The department comprises Hydrogeology, civil and Design sections. The department is responsible for initiating projects by way of preparing Bill of Quantities, supervision of on-going projects, Drilling, rig operations and civil construction works. •	ENGINEERING DEPARTMENT This department is responsible for installation of submersible water pump, well development and maintenance of boreholes 1.1.0      SERVICE OF THE EDO STATE URBAN WATER BOARD •	Edo state urban water board are into exploration of ground and surface water, using    geological equipment and borehole drilling for production of portable water for public usage.

UNDERGROUND WATER: this is a type of water body that is extorted from earth’s subsurface. They can be recharged by rainwater, stream, river, water, etc.

MODE OF RECHARGING: The mode of recharging of underground water is by precipitation and discharging from the surface water. 1.1.1     SCOPE OF EDO STATE URBAN WATER BOARD 1.	Edo state urban water board is into borehole drilling, especially in rural areas. The entire borehole drilled are industrial borehole, some are treated when necessary (i.e. when the aquifer is contaminated). 2.	They are also into surface water exploration. They pump water from Ikpoba river dam into their treatment housed where it will be treated and supplied for human consumption.

1.1.2     RELEVANCE WORK EXPERIENCE TO CAREER OPPORTUNITY The experience I have acquired during the course of my industrial training has really been of great help to me in knowing much about drilling of borehole and the Geophysical investigation of the earth’s subsurface. As a student of geophysics, I have been able to identify soil sample from different formation at a given interval. This sample includes laterite, coarse sand, fine sand, clay, silt, shale; well sorted and non-well sorted formation, as well as their color implies. 1.1.3  	 AIMS AND OBJECTIVES OF THE INDUSTRIAL TRAINING •	To enable students acquire a basic background and to acquaint themselves with the principle of Geology and Geophysical practices. •	To expose students to industrial understanding and services so that they fit into the society in the future for environmental remediation. •	To help students familiarize themselves with the general geophysical equipments, materials, and their uses.

ORGANOGRAM FOR EDO WATER BOARD

CHAPTER TWO GROUND WATER 2.1 INTRODUCTION For thousands of years, wells and naturals springs have supplied clean abundant groundwater to human communities throughout the world, the importance of groundwater, its formation, location and usage is very paramount. The earth hydrosphere extend from the top of the atmosphere to approximately 10km(6 miles) below the earth’s surface and includes the planet oceans, glaciers, rivers and lakes, atmospheric water vapor and groundwater. 2.2 WATER INFILTRATION The process through which water seeps through the earth without been absorbed by plants, attracted to clay minerals or evaporated through a zone of unsaturation to the zone of saturation is known as infiltration. The infiltration of water, mostly from precipitation into the earth’s surface in which the earth gains its water is termed groundwater recharge. When the earth is recharge, some of its water eventually flows out again as groundwater discharge returning to the surface as streams or springs, or remaining temporarily in lakes, pond, or wetlands. 2.3 FACTORS AFFECTING INFILTRATION: When water is infiltrated, it flows principally under the influence of gravity through soils rocks and sediment. The infiltration of water into the earth and the depth to which it descends is determined by the following conditions. 1.	Types of surface materials: The much pore spaces present in the loose soils and unconsolidated sands and gravel permits water to seep into the earth’s surface. If the exposed bedrocks is fractured (jointed or faulted) or porous (coarse sandstone). 2.	Topography: On gentle slopes, running water flows slowly and so has plenty of time to infiltrate the earth’s surface. Unlike gentle slopes, steep slopes and cliff faces allows water to flow rapidly so that a large percentage of the water runs down slope into nearby streams before they are infiltrated. 3.	Precipitation: The amount of rainfall that falls over a particular time affects the amount of groundwater recharge in any kind of terrain. Extended droughts may slow groundwater recharge significantly for years. This type of precipitation also affects infiltration, 4.	Vegetation: In the vegetated areas, about 35% of the precipitation lands on the leafy canopy of trees and evaporates before they reach the ground. The remaining 65% which falls on the land are evaporated or absorbed by plants, or runoff to nearby streams leaving a very small amount or precipitation to infiltrate. 2.4 GROUNDWATER MOVEMENT AND DISTRIBUTION Responding to the pull of gravity, water percolates down into the ground through the soil and through the cracks and pores in thee rock. The rate of groundwater flow tends to decrease with depth because sedimentary rock pores tend to be closed by increasing the amounts of cement and the weight of the overlying rocks. The subsurface zone in which all rocks openings are filled with water is called saturated zone (phreatic zone). If a well were drilled download into this zone, groundwater would fill lower fill the lower part of the well. The water level inside the well marks the upper surface of the saturated zone; this zone is the water table. Above the water table is a zone where not all the sediment or rock opening are filled with water. It is referred to as unsaturated zone. Within the unsaturated zone, surface tension causes water to be held above the water table. The capillary fringe is a transition zone with higher moisture content at the base of the unsaturated zone just above the water table. Plant roots generally obtain their water from belt of soil moisture near the top of the unsaturated zone, where fine-grained clay minerals hold water and make it available for plant growth. Most plants drown from their roots are covered by water in the saturated zones; plants need both water and air in soil to survive. The zone of saturation in most places do not extend to great depths, because the pressure of overlying rocks closes deep fractures and pore spaces re-crystallizing some rocks into impermeable crystalline metamorphic rocks. For these reasons most ground water is confined within the upper 1000meters (0.6miles) of the continental crust. Given adequate precipitation, the availability of groundwater depends on two characteristics of the soil or rock units into which the water can infiltrate. These are its porosity and permeability. 1.	Porosity: This is the total volume of pore spaces compared with the total volume of the soil, rock or sediments. It determines how much water can be held in a material. Porosity can be said to be primary, it developers as a rock is formed. On the other hand, it can be said to be secondary, if it develops after the rock is formed, usually as a result of dissolution and fracturing etc. In sedimentary rocks porosity is determined by such factors as cementation, grain shape and sorting. 2.	Permeability: This is the ability for a substance to allow the passage (flow) of fluid of fluid through it. The crucial factors that determines the availability of water is not how much fluid it can hold, but whether the fluid could go through the pores easily. The permeability of any material to a very large extent is controlled by the size of its pore space and the extent to which these pores space are connected. Only when the pore spaces are relatively large can the fluid go through it. 2.5      AQUIFER-WATER BEARING ROCK UNIT Aquifer (from Latin, meaning “to bear water”) is a permeable body of rock sediment, or soil that transmits groundwater and yet also stores significant amounts. Aquifer is the most common source of the ground water we use for our domestic, agricultural and industrial needs. The characteristic of a productive aquifer is that it consists of unconsolidated sand and gravel, well sorted grains, poorly cemented sandstone and highly jointed rocks such as basalt and limestone. 2.6      TYPES OF AQUIFER 1.	Unconfined aquifers: These types of aquifers extend nearly to the earth’s surface. Because the regional water lies within them, they are relatively easy to tap. The water in unconfined aquifer flow primarily through loose slope materials, sands, gravel etc. an unconfined aquifer is bounded by materials that are permeable. 2.	Confined aquifers: This comprise of water transmitting layers of rocks or sediment sandwiched between other layers or rocks that are either perfectly impermeable (Aquiclude) or have very low permeability (Aquitard). Unlike unconfined aquifers, confined aquifer resides at greater depth flowing through deeper layer of rocks far below the water table and the near-surface unconfined aquifer. 3.	Artesian aquifer: Sometimes the water in a confined aquifer may rise against the downward pull of gravity and even gush from the ground under certain geological conditions. Such a situation occurs where the confined aquifer is tilted at an angle to the earth’s surface, so that it becomes exposed at the surface in high mountain and because the Aquiclude and Aquitard prevent the water from escaping, the weight of the water in the inclined water column presses strongly on the underlying water, such that when the aquifer is trapped, the pressure drives the water upward. The type of aquifer is termed artesian aquifer. 4.	Perched aquifer: Perched water pools form in the zone of aeration when a local impermeable layer intercepts descending water. The quality of water here reduces as precipitation reduces and so it is never reliable.

2.7      FLUCTUATION OF WATER TABLE The water table always encounter a fluctuation in depth, i.e. a rise or fall of the water table as regards the depth from the earth`s surface. This fluctuation which occur daily and yearly owe its activity to several factors such as: A.	Tides: these are the daily rise and fall in water bodies e.g. oceans, large lakes etc. this rise in and fall in water bodies result from the combined effect of the gravitational pull from the moon and sun. B.	Climate: under certain climate conditions, some regions of the earth experience seasons of rainfall and drought annually because the earth gets its water (recharged) mainly from precipitation, it is expected that the water table in such regions increases (depth to water table reduces) during seasons of rainfall. On the other hand, during drought, evaporation is bound to take place, the usage of water by man, plants and animals increases; therefore, a drop in the level of water table is expected. C.	Rotation of the earth: Water is shapeless and as such take the shape of its container. The spinning of the earth around its axis causes fluctuation in water table. The rotation of the earth about its axis generally produces two high tides in coastal region each day. One when the region is on the opposite side, farthest away from the moon which is caused by the fact that the earth is a spinning sphere.

CHAPTER THREE 3.1		   		   GROUND WATER QUALITY Ground water quality is a function of natural process and anthropogenic activities. The natural process is dependent on factors such as, interconnection between surface water and aquifer, processes involving during ground water flow and storage, while anthropogenic activities result from inadequate abstraction or over exploration of ground water resources by urbanization, industrial and agriculture. 3.2 	ANTHROPOGENIC ACTIVITIES 1.	Urbanization: Over abstraction of the ground water and seepage from septic tank (water tank), lees pits and latrines tank is the biggest problem cause by (urbanization). The over abstraction of the ground water faster than average weight of recharge can result in falling water table. The fall in the water table below its original depth causes its land subsidence which can lead to cracks in septic tank an leakage from busted/sagged petroleum pipelines. 2.	Industrialization: Most industries produce liquid waste (effluent) which may or may not be treated to water course or surface flow. The worst polluter are not large industries which can afford some form of effluent treatment but small industries e.g. processing cassava, mechanic workshop and wood factories and farm produced. 3.	Agriculture: the intensive view of fertilizers an pesticides compose of high quality of Nitrate potassium and Chloride when leanced through porous and permeable formation can deteriorate the underground water system, morethan 300 pesticides and fertilizer are in used today and by definition they are design to be toxic and persistent with a concentration of 0.1-100 parts per billion in drinking water. Their behavior is control by their uptake by cops and susceptibility to leaching and degradation. 3.3 		NATURAL PROCESSES •	Interaction between ground water and the Aquifer: When water percolate (unsaturated zone) its quality is modified through such process as infiltration, evapo-transpiration, surface runoff and chemical weathering which lead to desolation of minerals. The water flows downward into the zone of saturation below the water table, where further reaction between inflowing water and host rock occurs. The factors which influence the solute content are the zone f saturation includes the original chemical composition of inflowing water, the distribution solubility and ionic exchange capacity of the ions, and the permeability and porosity of the rock. •	Reaction during ground water movement: ground water is complex solution which is in a dynamic state and its compositon is attributed to the solution in the material and rock by percolating water and to the chemical reaction between the water and the host rock. The dissolution of rock forming mineral is brought about by the acidic solution formed by co2 in rain water. •	However, greater amount are release by leaving and oxidation of organic matters in the soils and rocks. Thorne and Peterson approximated about 2-101 of Co2/day/m2 is given by living organism and oxidation of organic matter such as amount of co2 will give about 60-100mg/c of hco3 is formed by the reaction of co2 in rain water, although this increase due to release of co2 from exhaust of engines and factories.

CHAPTER FOUR 4.1	GEOPHYSICAL SURVEY The earth is inhomogeneous that is, it is made up of different chemicals and physical components. This inhomogeneity accounts for its complex nature of the earth, one of which involves using physical law to solve geologic problems. The branch of physics is called GEOPHYSICS. The process during which theses laws are used with the help of geophysical equipment to interpret the earth’s component over a particular area is called GEOPHYSICAL SURVEY. 4.2	TYPES OF GEOPHYSICAL SURVEY These are different type of geophysical survey and the purpose of its use is to determine the type of survey to be deployed. Some of these methods of survey are as follow. 1.	Electromagnetic Method (E.M) 2.	Magnetic Method 3.	Electrical Resistivity Method 4.	Gravity Method 5.	Seismic Method 6.	Remote Sensing 7.	Luminex Method 8.	Radioactive Method 9.	Grand Penetrating Radar (GPR) All the above Geophysical methods of survey are effective in their various area of application, and the selection of Geophysical method or survey is determined by what you are prospecting for. The suitable method and principal techniques of the Geophysicist in the search of groundwater are Seismic Refractions and Electrical Resistivity Methods.

4.3	ELECTRICAL METHOD: This method has 3 types which are Resistivity Method, Induced Polarization Method and Spontaneous Potential, but for the purpose of this course, we shall concentrate on Resistivity Method, which involves getting information from the subsurface and knowing their electrical resistivity of the properties that makes up Earth. The electrical resistivity method involves the passage of electric current into the ground though two current electrodes C1 and C2 while the potential drop is measured across another pair of electrode known as the potential electrode P1 and P2 which may or may not be within the current electrode C1 and C2 depending on their electrode configuration. The resistivity method of geophysical survey could be achieved using different type of array (methods in which electrodes are oriented) during field exercise. Some of the popular used array includes: •	Schlumberger Array •	Wenner Array •	Pole-Dipole Array •	Pole-Pole Array •	Dipole-Dipole Array •	Square Array 4.4 Field Deployment of Arrays: There are two ways in which any array can be deployed, which are as follows; 1.	Electrical Profiling or Constant Separation Traversing (CST) 2.	Vertical Electric Sounding (VES) Electrical Profiling can also be referred to Wenner array in regard to electrode configuration while vertical electrical sounding can also be called Schlumberger array. In the course of my industrial Training, Vertical Electrical Sounding (VES) was used. •	Electrical Profiling- This is called constant separation traversing (CST). The electrical profiling determine the value of the horizontal direction. The current is passed into the ground by the use of two electrode (current electrode) while the potential difference is measured by the use of two electrode (potential electrode). And also, these four electrodes are usually arranged in such a way that the distance between them are equal, these type of arrangement are called Wenner array. It is used largely for investigating lateral resistivity variation and it helps to reveal some structural element within the earth surface.

A typical arrangement of Wenner array is shown above.

4.5	VES ELECTRICAL SOUNDING (VES) Vertical Electrical Sounding is the use of electrical method with depth control in which the potential electrodes are temporarily kept fixed. A center is chosen while the current electrode spacing is increased to obtain information MN/2 (m) often used in field studies. In this form, the spacing of the four electrodes is not equal, and this type of arrangement is called Schlumberger Array.

4.7	OHM’S LAW AND RESISTIVITY Ohm’s law is the fundamental principle governing the electrical resistivity survey. The law states that the current (I) flowing in a body is directly proportional to the applied voltage (V) across the end of the body. Mathematically, we have that; V α I But V = IR R=V/I							(2.1) Where V is the applied voltage and it is measured in volt V, I is the current in ampere in conductive body and R is the Resistivity in ohms. The surface Resistivity ρ is defined by ρ = RA/L							(2.2) Where; A is the cross-sectional area of the path of flow of current and L is the distance through which current flow, the S.I unit of resistivity is Ohmmeter (Ωm) and the reciprocal of resistivity is called conductivity, its unit is Siemens per meter (sm-1) 1sm-1=1Ω-1m-1. Since the resistivity measured are normally made by passing current into the ground through two current electrodes C1 and C2 and measuring the resulting potential difference at two potential electrodes P1 and P2. From the current and voltage (V) values an apparent resistivity (Pa) value is calculated, hence; Pa =KV/I							(2.3) Where; K is the Geometric factor, and given the resistance value R=KV/I, therefore, the apparent resistivity is calculated by; Pa=KR. In Wenner electrodes array K have been proven as K=2πa Where a is the electrode spacing. Hence, the apparent resistivity Pa = 2aπR                 (2.4) While in Schlumberger electrodes array, k has been proven as; K =

Where AB/2 = the current electrode spacing from the center point, MN/2 = the potential electrode from the center point. Since the apparent resistivity is known to be

Pa = π These array differs from one another in their orientation hence, in Schlumberger, the electrode are arranged in such a way that the potential electrode on P1 and the potential electrode two P2 which is AB/2 are kept in a distance with the if the current electrode one C1 and current electrode two C2 as shown above.

4.7. 	COMPARING WENNER AND SCHLUMBERGER ARRAY 1.	Resolving Power: This is the ability to discriminate between two features. Wenner is about 10% better than Schlumberger, but both are about three to four times better than two electrode array in theirs resolution power. 2.	Field Convenience: •	Electrode movement: Schlumberger is more convenient than Wenner because in Wenner, the entire four electrodes are moved while in Schlumberger, the entire four electrodes are not necessary moved. •	Cable Length: The cable length required is shorter in Schlumberger than Wenner. 3.	Energy input: Wenner requires less energy for a given AB/2 than Schlumberger.

4.8. 	GEOPHYSICAL SURVEY EXERCISE Equipments/Materials required for geophysical survey •	Cable Reels •	Resistivity Meter •	Battery •	Measuring Tape •	Clips •	Compass •	Geological Hammer •	Global Positioning System •	Field Notebook •	Electrodes •	Cutlass •	Walkie Talkie During field exercise, a base station should be located, that is where the equipments will be based. After this, the current cable reels are connected to the electrodes and with another cable connected to the resistivity meter in the current pin (C). The potential cable reels follow suits and it is connected to the potential pin (P). After this is done, the tetrameter is finally connected to the battery which acts as a source of power to the resistivity meter. 4.9	PRODCEDURE FOR ELECTRICAL RESISTIVITY •	Extension of current electrodes: During field work the current electrodes are extended from time to time to take resistivity readings. The depth covered beneath the earth is determined by the extent to which the electrode is extended. The longer the distance, the deeper the current can be sent into the earth’s surface. The distance covered is literally determined by the geology of the area. •	Extension of the potential electrodes: The potential electrodes may be extended during the field work when the reading obtained from the signal averaging system is reducing. When the current electrodes are extended too far from the potential electrodes, the ability for it to receive signal reduces, therefore, the potential electrodes needed to be adjusted closer to the current electrodes.

4.1.0	PROCESSES INVOLVE IN GEOPHYSICAL SURVEY 1.   Data Acquisition 2.   Data Processing 3.   Data Interpretation

1.	Data Acquisition: This is the first stage of survey. It’s the collection of data from the survey field. In electrical resistivity survey signal to noise ratio has been reduced to the nearest minimum by the electrical resistivity meter, which help the Geophysicist to read the data. 2.	Data Processing: This process is of two forms namely; a.	Digital Data Processing b.	Manual Curve Matching a.	Digital Data Processing: In this type of data processing; it is done directly by the electrical resistivity meter, immediately any voltage signal from a station entered it. b.	Manual Data Processing: The graph of apparent resistivity is plotted against AB/2 (m). This is the distance between two current potential. 3.	Data Interpretation: In data interpretation, it means what and what is likely to be present in the subsurface area of a survey field by using the plotted graph. 4.1.1	IMPORTANCE OF VERTICAL ELECTRICAL SOUNDING IN GROUND WATER EXPLORATION 1.	It helps in delineating where exactly clean water can be obtained. 2.	It goes deeper into the earth surface. 3.	It is fast, since it is only the current electrode that is been moved. 4.1.2	FIELD PRECAUTIONS During field exercise, precautionary measures must be put in place to avoid loss of equipment and to obtain effective results. If the precautions below are strictly adhered to, it will increase accuracy and reduce any form of abnormality. 1.	Equipment Testing: Test and make sure that all part of the tools and equipments are in good working conditions before setting out for the field. The tetrameter also should be avoided from direct rays from the sun while in the field. 2.	Surface in homogeneity at electrode position: The electrodes should not be positioned at points where there are surface in homogeneity. E.g. A heap of dirt. 3.	Electrode Grounding: Effort should be made to make sure the electrode is properly grounded. 4.	Ground Conductivity at electrode position: At points where the ground is relatively hard, the electric conductivity will not be sufficient and this may lead to erratic readings. In such case the ground should be wetted with water to increase its conductivity. 5.	Consistence Reading: It is advisable to repeat readings at a point to ensure consistency. 6.	Leakage: Green plant can conduct electricity, therefore causing leakage of current from the contacted electrodes. Also, exposed cables can cause leakage of current. 7.	Cable Integrity: Before carrying out any exercise, check for the continuity of the cable (current flow) and if any part is exposed, it should be done before extending the cable. 8.	Line Orientation: The lines should be oriented in such a way that it does not run along steep slope. This is because the current electrodes will be sampling a different volume of the earth. It is better to run lines across the slope so as to ensure accurate and sound values. 4.1.3	FACTORS AFFECTING CONDUCTIVITY OF EARTHS MATERIALS The earth is made up of different components (Chemical, Physical, Electrical etc.) and so it is not homogenous. The conductivity of earths material varies over a wide range, this means that for a given medium or rock type, the conductivity will depend on a number of factors. 1.	Porosity: This is the ratio of the volume of pore to the total rock volume (Vv/Vt). 2.	The degree of saturation of porous materials. E.g. the vadoze zone and the phreatic zone. 3.	Nature of pore fluids E.g. water and hydrocarbon. 4.	Nature and size of the grains. 5.	Whether the material is consolidated or not. Consolidation is a porosity reduction process. 6.	Bulk porosity of large volumes.

Cable reels, hammer, electrodes, and helmet. CHAPTER FIVE 5.1	BOREHOLE DRILLING Borehole drilling is a process of cutting a hole through the earth continuously and flushing the cuttings from this hole followed by a systematic insertion of casing rod when the point of interest is reached. Prior to drilling, some factors need to be considered. These factors give a clue or information about the area to be explored. They include the recognizer survey, geophysical survey etc.

5.2	. Recognizer survey: These involve getting familiar with the terrain, making inquiries about the terrain, such as, has there been a borehole in the area before? If yes, is it still functioning? How long did it take to get to the desired aquifer (depth)? This formation helps to generate a data plan, the equipment to be used (such as the strength of the rig, drilling method etc.), and most importantly the cost for the exploration. The recognizer survey could be divided into the geology of the area and hydrogeology of the area. i.	Geology of the area: this deals with the information concerning the formation of the area, whether the area is sedimentary or a basement complex, orientation of the topography, vegetation of the area. This information helps to determine the types of drilling bits to be used, manual effort to be engaged, etc. ii. Hydrogeology of the area: this includes factors such as the drainage system within the area and precipitation 5.3.	 Geological survey: After the recognizer survey, the geophysical survey exercise is  carried out to determine the resistivity of the subsurface materials 5.4.	 TYPES OF BOREHOLE There are different type of borehole depending on the depth and width; the following are the types of boreholes 1.	Shallow borehole 2.	Deep borehole 3.	Wide borehole 5.5.	 QUESTIONS ON BOREHOLE DRILING Before a borehole drilling commence there are some questions that people involved need to ask. The following questions are; 1.	When to bore a hole 2.	Where to bore a hole 3.	How to bore a hole 1.	When to bore a hole; it is the responsibility of the authorities in charge to know when the people in a particular area needed a borehole, which is one of the major functions of water cooperation

2.	Where to bore the hole; from the desk study and survey of the area carryout from an area, the field Geologists/Geophysicists will be able to locate a particular spot where portable water can be delineated.

3.	How to bore the hole; how to bore a hole is actually a question per say, because of the breakthrough in technology, the survey of the area will direct the field Geologist/Geophysicists on how to go about the boring of the hole.

5.6. SOME TERMS USE IN BOREHOLE 1.	Aquifer 2.	Aquiclude 3.	Aquifuge 4.	Aquitard

1.	Aquifer: An aquifer is a typically saturated region of the subsurface that produce an economically feasible quantity of water to a well or spring (e.g. sand and gravel or fractured bed rock often make good materials) 2.	Aquiclude: An aquiclude is an impermeable body of rock or stratum of sediment that acts as a barrier to the flow of groundwater, it is a saturated Geologic unit that is incapable of transmitting significant quantities of water ordinary (i.e.is rock that bear water but cannot give it out) 3.	Aquifuge: This is a body of rock that is incapable of absorbing or transmitting water, hence rendering it impermeability. That is a rock that does not bear water at all. 4.	Aquitard: An Aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another. An Aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitard comprises of layers of either clay or non-porous rock with low hydraulic conductivity.

5.7.	METHOD OF BOREHOLE CONSTRUCTION

There are various types of borehole that may be constructed for various purposes, borehole construction method may be defined as the set of activities, materials, processes, equipment and tools employ for the extraction of an economically sustainable water supply of desirable quality and quantity from the subsurface. There are 3 phase of operation in the process of borehole construction namely:

A.	Drilling. B.	Well completion. C.	Well development Due to the varying characteristic and properties of different rocks types, different method are employ to achieve best result are been employ for each of these phases. DRILLING: involves the actions of breaking cutting or dislodging the formation material, clearing out the cuttings from the hole and stabilizing the walls of the hole for completion. The method of drilling that best carry out these functions and most commonly used and they include Cable Tool Drilling and Rotary/Rotary hammer drilling. 5.8.	CABLE TOOL DRILLING: The operating principle of cable tool drilling entails the lifting and dropping of a drilling string, suspended on a cable. In the process, the formation material broken, clearing the hole of cuttings its done by the use of bailer. Sometimes drilling mud is use to stabilize the wall of the borehole, therefore cable tool is best used for drilling: a)	Unconsolidated formation b)	Soft sedimentary and weather rocks c)	Lost circulation formation d)	When testing and sampling H2O supply e)	When there is a need to identify water flow 5.9.	 ADVANTAGES OF CABLE TOOL DRILLING 1.	The cable tool has advantage for water well drilling because of the details sub-surface information it provides 2.	The machine is cheap and easy to maintain 3.	Consumable drilling are low therefore the method is suitable for drilling in remote areas. 5.1.0. DISADVANTAGES OF CABLE TOOL DRILLING 1.	In deep drilling, it is difficult to maintain the borehole in a free state for the running of the casing 2.	In hard rock`s the cable tool drilling has a low rate of penetration. 3.	The heavy hammering that is involved in the cable tool drilling will destroy and damage some formations. 4.	It may not be possible to run an electrical logging on the borehole, if the wall was cased while drilling. 5.1.1.	ROTARY DRILLING: This method of drilling as by far developed beyond the cable tool drilling method and its most widely used. The operating principle of drilling is the crushing/cutting the rocks by the rotational movement of a drill bit at the bottom of the hole. Drill cutting are cleaned from the hole by drilling fluids which could be water, mud, air, mist or foam. In soft to medium formation, the borehole wall is stabilized by mud. In hard formation, drilling is best carried out by rotary down hole hammer drilling. The principle of breaking the rock is that the bits rotate slowly while the pestle is moving up and down in a cylinder behind it. Clearing the cuttings from the hole is achieved by circulating air, mist or foam. 5.1.2.	FEATURES OF ROTARY DRILLING: Some features and characteristics of rotary drilling methods that should be noted are drive mechanism and the use of mud. 1.	Rotary drive: These are 3 principal types of rotary drives namely: •	Rotary table drive: The rotary is rotated and thus in turn drives the pipe. •	Top head drive: A hydraulic power head drives the pipe directly. •	Turbines drive: Down-hole turbines driven by circulating fluid rotate the bits. 2.	Drilling mud: These are used to clear cuttings from the borehole and stabilize the borehole walls. In addition to these, drilling fluid have the following functions: i.	It cools the bits. ii. Lubricate the bits. iii. Control fluid loss. iv. Drop cuttings in the mud pits. v.	Keep the cuttings suspended in the borehole when the mud is not in circulation. 5.1.3.	ROTARY HAMMER DRILLING: This method of drilling has it application for drilling in hard and medium rock formation. This method achieve a rate of penetration and good hole straightness. Hole making is achieve by turning the bits slowly while a heavy pest ling move up and down in a cylinder behind it. Generally, the use of any type of drilling method is largely dependent on the purpose of borehole (domestic or industrial), the geology of the area ( sedimentary or basement), and other factors like depth of the water table. 5.1.4.	MATERIALS/EQUIPMENT REQUIRED FOR DRILLING 1.	Water 2.	Chemical (antisols, benthonite etc.) 3.	Drilling rods. 4.	Casing pipes. 5.	Screen pipes 6.	Marine ropes 7.	Rice gravel 8.	Submersible pump 9.	Drilling bits 10.	Well rig 11.	Drilling rig 12.	Water tanker 13.	Cranes.

5.1.5.	WELL COMPLETETION: This may be view as techniques of making and retaining an efficient connection with desirable aquifer, while efficiently starting off undesirable horizons in the surfaces. These objectives are achieved by the use of casing, screens and seals. 5.1.6.	CASING SELECTION: The numbers of factors that are taken into consideration in the selections of casing for well completion. 1.	The casing must be current size to accommodate design pumps size. 2.	The casing must have the strength to withstand down-hole pressure. 3.	Casing must have the characteristic to resist correction. 4.	Casing must be of correct length. 5.	Casing must be durable 5.1.7.	COLLECTION OF SAMPLES: From the broken fragments brought to the surface are collected at the interval of 10ft each. Samples are collected with regards to the drilling rods. It is the sample that tells the geologist the formation been encountered. When these samples are collected, they are washed clean with clean water to reveal the characteristic of that formation. The sample shows lithology of area with the topmost soil being the first. 5.1.8.	WELL DEVELOPMENT: When the boreholes as reached the proper level, the tools are withdrawn and casing is lowered to the bottom of the well. With part of its selectively screened to allow water from the reservoir (aquifer) to enter into the well. The opening on the screen are selected on the basis of grain size distribution in the aquifer, to permit at least 50 to 70% of the particles of the aquifer near the well, to pass through the screen, the borehole is developed by pumping air at a high rate (airlifting), which agitates the materials around the screen and permits finer particles to enter the borehole from which they are removed by pumping. The top of the well near the surface is then grouted with concrete. The casing material for the industrial use is the API and for the screen, a Johnson screen is used. For the domestic use, PVC is advisable. A pumping test is carried out, after which a submersible pump is installed. The pumping test which is done ascertain the yield, determines the strength or size of the submersible pump. The installation of submersible pump is the last stage in borehole development.

CHAPTER SIX 6.0	CONCLUSION My industrial training with Edo State Urban Water Board has exposed me to the practical application of geophysics method. I also gained experience in the aspect of geophysical explorations and its data interpretation. 6.1	RECOMMENDATION My recommendation is directed to the following group of people To the students All efforts should be made to fully understand the basis theory of their discipline upon which practical are built. To the university The university should form a strong link with the industry via the departments to solve the problem of student’s placement. I also recommend the review of the duration of SIWES training.

6.2					REFERENCES •	Edo State Urban Water Board	 2016 •	Images from http://images.google.com •	Introduction to geophysical exploration by Michael Brooks and Carrey •	Legalize Geophysical consultant 07062041666 •	A. Iyoha, S. Ehika and O.E Akhirevbulu,(2010) “Delineation of Aquifer in Ikokha Village in Ovia south west local government area of Edo state Nigeria” •	Physical Geology Fourteenth Edition by Plummer and Carlson. •	Reyment R. A (1965). Aspect of Geology of Nigeria. Ibadan University Press. Pp. 145. •	Ujuanbi and M. B. Asokhia. The Vertical Electrical sounding. A viable tool for the investigation of clay deposits. •	Ozegin K. O. et al (2012), Integrated Geophysical Investigation and Characteristic of Aquifer structures in a Complex Environment. -->