Geophysical Investigation for Groundwater Potential in Rufus Giwa Polytechnic Owo, Southwestern...

The International Journal Of Engineering And Science (IJES)

|| Volume || 4 || Issue || 11 || Pages || PP -29-39|| 2015 ||

ISSN (e): 2319 – 1813 ISSN (p): 2319 – 1805

www.theijes.com The IJES Page 29

Geophysical Investigation for Groundwater Potential in Rufus Giwa

Polytechnic Owo, Southwestern Nigeria

1O.O. Falowo,

2A.O. Daramola ,

3O.O. Ojo

1,2,3Department of Civil Engineering, Faculty of Engineering Technology, Rufus Giwa Polytechnic,

Owo, Ondo State, Nigeria.

------------------------------------------------------------ABSTRACT---------------------------------------------------------------

Geophysical investigation was conducted at Rufus Giwa Polytechnic, Owo, Southwestern, Nigeria with the aim of

evaluating the groundwater potential in the area. The geophysical survey involved Very Low Frequency

Electromagnetic (VLF-EM) and Vertical Electrical Sounding (VES). A total of twenty seven (27) traverses were

established along West – East and Southwest – Northeast direction in the studied area; covering a total distance of

8.45 km. The lengths of the traverses vary between 110 m and 920 m. Measurements were taken at 10 m spacing

along the traverses for the VLF-EM. The result of the VLF-EM was used to determine the data point for the VES.

The VLF-EM result reveals the presence of conductive zones. The geoelectric section revealed 3 to 5 major layers

comprising the topsoil, clay, laterite, weathered layer, partly weathered layer/fractured basement, and fresh

basement rock. The topsoil has resistivity that varies between 46 Ω-m and 1644 Ω-m, and depth that ranges from 0.3

m to 19.8 m. It is composed of clay/sandy clay, clayey sand, lateritic clay and laterite. The clay substratum has

resistivity that ranges from 20 to 95 Ω-m and depth that varies from 1.5 m and 9.3 m. Laterite is characterized by

resistivity that varies between 106 Ω-m and 1223 Ω-m with thickness that varies from 0.8 m to 11.4 m. The

weathered layer which constitutes the first aquiferous zone and is characterized by resistivity that ranges between

28 Ω-m and 823 Ω-m, while its thickness varies from 0.4 m to 144.2 m. The composition of the weathered layer is

predominantly clayey sand indicating an aquitard i.e. a subsurface geological formation that stores but fairly

transmit water. The partly weathered layer/Fractured aquifer is the second aquiferous zone; it has resistivity that is

between 16 Ω-m and 914 Ω-m with thickness in the range of 0.3 m to 148.6 m. The fresh basement has resistivity

values that vary from 327 Ω-m to 17578 Ω-m. The low resistivity values (< 500 Ω-m) are due to screening effect by

the overlying conductive material. The weathered layer and fractured basement aquifers correlate the suspected

water filled geologic formation observed by the VLF-EM. Therefore the area shows a very good prospect for

groundwater development.

Keywords – aquiferous zone, conductive material, geological formation, geophysical investigation, groundwater

------------------------------------------------------------------------------------------------------------- -------------------------------

Date of Submission: 14 November 2015 Date of Accepted: 30 November 2015

-------------------------------------------------------------------------------------------------------------------------- ------------------

I. INTRODUCTION Access to clean water is a human right and a basic requirement for economic development. The safest kind of water

supply is the use of groundwater. Groundwater accounts for about 98 % of the world‟s fresh water and is fairly

evenly distributed throughout the world. It provides a reasonable constant supply which is not completely

susceptible to drying up under natural condition unlike fresh water. Water from beneath the ground has been for

domestic use, irrigation and livestock. Lakes, swamps, reservoirs and rivers account for 3.5 % and soil moisture

accounts for only 1.5 % ([4]).

The works of ([1], [3]) revealed that it is necessary to monitor water quality on regular basis. Since groundwater

normally has a natural protection against pollution by the covering layers, only minor water treatment is required.

Detailed knowledge on the extent, hydraulic properties, and vulnerability of groundwater reservoirs is necessary to

enable a sustainable use of the resources. The total replenishable water resource in Nigeria is estimated at 319 billion

cubic metres, while the groundwater component is estimated at 52 billion cubic metres. Nigeria has adequate surface

and groundwater resources to meet its current water demands. However, in spite of the tremendous efforts put by the

various Governments to improve access to potable water supply to all Nigerians, estimates shows that only 58% of

the inhabitants of the urban and semi-urban areas and 39% of rural areas have access to portable water supply.

Geophysical Investigation for Groundwater Potential…


Water shortages are acute in some major centres and in numerous rural communities due to a variety of factors

including variations in climatic conditions, drought increasing demands, distribution system losses, and breakdown

of works and facilities. Other challenges facing the sector include funding constraints for improving and

rehabilitating broken down schemes, competition between water users, pollution from point and non-point sources

and lack of competent and skilled human resources.

1.1 Description of the Project Environment

Rufus Giwa Polytechnic, Owo, Ondo State, is located in Owo “Fig. 1” which is within the south western part of

Nigeria. The institution “Fig. 2” is situated in Owo local Government of Ondo State “Fig. 3”. It lies within

longitudes 6 ̊ 00ˡ E and 5 ̊ 30ˡ E and latitudes 7 ̊ 30ˡ N and 7 ̊ 00ˡ N. The study area is easily accessible by roads like

Ikare – Owo highway, Benin – Ifon highway and Akure – Owo highway.

1.2 Geomorphology, Climate and Vegetation

Owo is relatively flat, as the terrain ranges from 940 ft to 1100 ft “Fig. 4”. The terrain slopes from Rugipo down to

Isuada town “Fig. 5”. Elevation is much higher at Ikare Junction and lower around Emure and Isuada towns. In

RUGIPO, the topography ranges from 311 m to 342 m above the sea level. The study area has a gently undulating

topography. The area lies geographically within the tropical rain forest belt of hot and wet equatorial climatic region

characterized by alternating wet and dry climate seasons ([6]), which is strongly controlled by seasonal fluctuation

in the rate of evaporation.

The available rain data shows that mean annual rainfall ranges from 1000 mm - 1500 mm and mean temperature

of 24 ̊ C to 27 ̊ C. There is rapid rainfall during the month of March and cessation during the month of November.

June and September are the critical month when rainfall is usually on the high side. The vegetation is of tropical

rainforest and is characterized by thick forest of broad-leaved trees that is ever green. The vegetation of the area

(especially in undeveloped areas) is dense and made up of palm trees, kolanut trees and cocoa trees. Part of this area

is also made the school farm.

1.3 Geology of the Studied Area

The area of study falls within the Southwestern basement rock “Fig. 6” which is part of Nigerian Basement

complex. The area is underlain mainly by rocks of the Migmatite - Gneiss Complex “Fig. 7”. RUGIPO is

predominantly underlain by quartzite, granite and granite gneiss “Fig. 8”.

Quartzite is the most dominant rock; which mineralogically contains quartz dominating mineral, other minerals

such as muscovite, tremolite, microcline and biotite are common as well. Quartzites which are prominent as ridge

vary in texture from massive to schistocity due to the presence of flaky minerals like mica.

II. METHODS OF STUDY Twenty seven traverses were established in W-E and SW-NE direction with length that varies between 110 m and

920 m “Fig. 9”. The total length of the traverses established is 8450 m (8.45 km).

Figure 1: Road/Administrative Map of Ondo State

IgbekeboIgbokoda

Ore

IreleOkitipupa

Okeluse

Ute

Ifon

Ipele

Sanusi

OkpeEmure

Sasere

AyereOke-Agbe

Auga

Ise

IbilloIsua

OkaIkare

Ikun

AfoIdoani

Akungba

IkunOgbagi

Arigidi

Oba

Uso

IjuIta ogbolu

Ijare

Akotogbo

OtuOmotosoKajola

Oniparaga

Ode-Aye

Igbotaku

LodaAyadi

Ondo

Ibagba

Asewele

OminiaOdigbo

Ofosu

Omifunfun

Jimgbe

Odole Ala-Ajagbusi

Oba-IleAkure

Onikoko

Araromi

Ile-Oluji

AladeIdanre

ESE-ODO

ILAJE

IRELE

OKITIPUPA

ODIGBO

ONDO-WEST

IDANRE

ILE-OLUJI

Bolorunduro

IFEDORE

AKURENORTH

OWOOSE

AKOKO SW

AKOKO NE

AKOKO NW

AKOKO SE

EDO STATE

EKITI STATE

OSUN STATE

OGUNSTATE

DELTA STATE

KOGISTATE

ATLANTIC OCEAN

MAIDUGURI

ENUGU

MAKURDI

ILORIN

SOKOTO

KANO

LAGOS

AKUREIBADAN

ABUJA

N

L. Gov't. Headquarters

Towns & Villages

Minor Road

Major Road

6 00o

5 30o

5 00o

4 30o

6 00 Eo

4 30 Eo

5 00o

5 30o

6 00 No

6 30o

7 00o

7 30 No

6 00 No

6 30 No

7 00o

7 30o

State Boundary

025 25 Km


www.theijes.com The IJES 1

Figure 2: Land-Use Master Plan of RUGIPO

Figure 3: Map of Owo Local Government Area of Ondo State

O.S.P.O. CONSULT

ACTIVITY AREA

AREA FOR

FUTURE

AGRICULTURAL

DEVELOPMENT

GAMES RESERVE

RESERVATION

O.S.P.O. CONSULT ESTATE AREA

MANAGEMENT STAFF QUARTERS

NEW SPORTCOMPLEX

Ata

mopere

Strea

m

AGRICEXTENSION AREA

ARTIFICIAL LAKE

STAFFCLUB

HOSTEL

HO

ST

EL

SCHOOL OF BUSINESSSTUDIES

SCHOOL OFGENERALSTUDIES

SCHO

OL O

F

ENG

INEER

ING

TECHNO

LOG

Y

SENIOR STAFF

QUARTERS

EXPANSION

Ope

Stream

JUNIOR S

TAFF QUARTERS

COMMERCIAL SCHOOL OF FOODTECHNOLOGY

CENTRAL AUDITORIUM/ADMINISTRATIVE/CONFERENCE CENTRE

PLACE OFWORSHIP CENTRAL

POOL

OSPO. COMM. CEN.

RESEARCH/PRESS CENTRE

PART-TIME STUDENTS RESERVATION

DAM

ETFRESERVATION AREA

From Akure

To Oluku

C.S

REC

NC

STAFFCLUB

G.H.

MAINTENANCE DEPT.

O.S.P.O.GUESTHOUSE

PLACE OFWORSHIP

W.T.

SUB.

ALUMNICENTRE

344000E 345000 346000 347000 348000 349000 350000E

344000E 345000 346000 347000 348000 349000 350000E

356000N

357000

358000

359000

360000

361000

361250N

356000N

357000

358000

359000

360000

361000

361250N

Quarry

Aau

nke

Str

eam

Gate

560m0 560 1120 1680m

Existing Road

Boundary Pillar

Fence

Proposed Roads

Streams

Trees and Hedges

Commercial Centre

Faculties/ConferenceCentres

Administrative Blocks/Conference Centres

School Boundary

Hostel

Management Staff QuartersLecture Halls/Existing Buildings

New Sport Complex

Artificial Lake/Pond

StadiumGate

R.C. Recreation Ground

S.U.B. Student Union Building

C.S. Corner Shop

O.S.P.O. Ondo State Polytechnic, Owo

W.T. Waste Treatment

Ceded Land

LEGEND

MAIDUGURI

ENUGU

MAKURDI

ILORIN

SOKOTO

KANO

LAGOS

AKUREIBADAN

ABUJA

N

AK

UR

E N

OR

TH

L.G

.A.

IDA

NR

E L

.G.A

.

AKOKO SOUTH WEST L.G.A.

OS

E

L.G

.A.

EKITI STATE

Igbatoro

Alafiatayo

AraromiSanusi

Emaajomo

IseweOkififioko

Daji Camp

Sasere

Ago-Panu

Ipeme

Ipele

Iyere

Baga

Eporo

Obasoro

IlaleAlasa

IjegunmoOlefa

Igodi

Oluka

Odofin-Alaro

Alaga

EmureRUGIPO

Uso

Ago-Panu

Amurin

Ipele Junction

Isijogun

5 15 E

5 15 E

7 30 N 7 30 N

6 00 E

6 00 E

6 45 N6 45 N

Major Road

Minor Road

Main Paths

RUGIPO

Towns and Villages

Rivers and Streams

LEGEND

0 5 Km

SCALE



Figure 4: Topographical map of Owo and Environs

Figure 5: 3-D Surface Elevation Map around the studied Area



Figure 6: Geological sketch map of Nigeria showing the major geological component; Basement,

Younger Granites, and Sedimentary Basins ([5]).

Figure 7: Geological Map of Owo and Environs, showing the Study Area ([5]).

Owo

Study Area



Figure 8: Geological Map of RUGIPO

Figure 9: Data Acquisition Map of the Study Area

N

OSPO CONSULTESTATE AREA

CEDED AREA

Management Quarters

AREA FOR FUTUREAGRICULTURALDEVELOPMENT

AGRIC EXTENSIONAREA

HOSTEL

GAMES RESERVE

RESERVATION

Atam

oper

eSt

ream

STAFFCLUB HO

STEL

SCHOOL OF BUSINESSSTUDIES

SENIOR STAFF

QUARTERS

EXPANSION

Ope

Stream

From Akure

To Oluku

344000E 345000 346000 347000 348000 349000 350000E

344000E 345000 346000 347000 348000 349000 350000E

356000N

357000

358000

359000

360000

361000

361250N

356000N

357000

358000

359000

360000

361000

361250N

Quarry

560m 0 560 m

Quartzite

Granite Gneiss / Granite

Dam Quarry

Ceded Area

Stream

LEGEND

SUB

S.S.

ST

AD

IUM

ADMINISTRATIVE BUILDING

HEALTH CENTRE

FACULTY OF GENERAL STUDIES/MASS COMMUNICATION DEPT

School F

arm

LOW RISE

MANAGEMENT QUARTERS

356000N 347000E

357000

357750

348000E

0

To Akure

To Ifon

Road

Grid Lines

Gate

Traverse Line(VLF & Magnetic)

200 m

GUESTHOUSEARTISAN

LIBRARY

ICT

Hoste

l

Ho

ste

l

Block-Five

POULTRY

Millenium Lecture Theatre

CE

DE

D A

RE

A

Minor Path

VES Point

SCALE:

LEGEND

Stream

Tr.1

Tr.19

Tr.2Tr.3

Tr.4

Tr.5

Tr.6Tr.7

Tr.8

Tr.9

Tr.10

Tr.11

Tr.12

Tr.13

Tr.14

Tr.15

Tr.16

Tr.

17

Tr.18

Tr.20

Tr.21

Tr.22

Tr.23

Tr.24

Tr.25

School F

arm

School F

arm

Tr.26

Tr.27

Borehole Location

Hand Dug Well Location

B.Tech.Est. Mgt

V1 V2V3

V4 V5

V6

V7

V8 V9 V10

V11

V12V13

V14

V15

V16

V17

V18

V19

V20

V21

V22

V23

V24

V25

V26

V27

V28

V29

V30V31

V32

V33

V34 V35

V36 V37

V38 V39 V40V41

V42

V43V44

V45

V46 V47

V48 V49 V50 V51V52

V53

V54

V55

V56 V57 V58

V59

V60 V61

V62

V63

V64 V65V66

V67

V68

V69 V70

V71

V72V73 V74 V75

Tr.1 Traverse Number

V8 VES Number

VLF & MagneticData Point



2.1 VLF-EM Survey

The VLF - EM method utilized the inline profiling technique. The measurements were taken at 10 m intervals along

each traverse. The ABEM – WADI EM-VLF was used for the measurements. Although both real and quadrature

components of the VLF-EM field were measured, the real component data, which are usually more diagnostic of

linear features, were processed. The real and filtered real components were plotted against stations position using

„KHFFILT‟ software version 1.0 ([7]). The 2-D modeling of the filtered real component was carried out using the

same software. The profiles were interpreted qualitatively by visual inspection of anomalies (conductor) that are

diagnostic of possible geological structures in the bedrock while the 2-D modeling output was used for quantitative

interpretation.

2.2 Electrical Resistivity Survey

The electrical resistivity method utilized Vertical Electrical Sounding (VES) using the Schlumberger array. The

same traverses were used in each locality as in VLF method. Sounding stations were determined from conductive

zones delineated by the VLF – EM. The location of each sounding stations in both geographic and Universal

Traverse Mercator (UTM) coordinates was recorded with the aid of the GARMIN 12 channel personal navigator -

Geographic Positioning System (GPS) - unit. The instrument used for the resistivity data collection was the Omega.

The current electrode spacing (AB/2) was varied from 1 m to 225 m. The apparent resistivity(𝜌𝑎 ) resistivity

measurements at each station were plotted against electrode spacing (AB/2) on bilogarithmic graph sheets.

The resulting curves were then inspected visually to determine the nature of the subsurface layering. In each way,

each curve was characterized depending upon the number and nature of the subsurface layers.

Partial curve matching ([9]) was carried out for the quantitative interpretation of the curves. The results of the

curve matching (layer resistivities and thicknesses) were fed into the computer as starting model parameter in an

iterative forward modeling technique using RESIST version 1.0 ([10]). From the interpretation results, geoelectric

sections along the traverses were produced. The interpreted result was considered satisfactory since a good fit of

RMS between the field curves and computer generated curves.

III. RESULTS AND CONCLUSION 3.1 Field Curves

The number of layers varies between 3-layers and 6-layers. Nine curve types have been identified in the study area:

KH, HKH, H, KHKH, QH, HK, KQ, AK, and KAH. The most occurring curve types identified are KH and HKH

curve types “Fig. 10”. The root mean square (RMS) error of the generated curves ranges between 1.8 and 10.7; this

shows models of well smoothened, iterated curves ([2]).

3.2. 2-D VLF – EM Modeling and Geoelectric

Section

The 2-D structure of the real component of the VLF – EM along Traverse 2 is shown in “Fig. 11a”. The 2-D

structure reveals one strongly conductive zone located around 45 and 87 m. This structure has a depth greater than

20 m. This conductive is suspected to be a thick weathered zone or fractured zone. The geoelectric section along this

Traverse shows that VES 1, 2 and 3 have thick weathered layer indicating good aquiferous unit for groundwater

prospect. The most occurring resistivity range of 400 Ω-m – 700 Ω-m suggests a clayey sand/sand formation which

is an aquitard i.e. a subsurface geological formation that can store water but poorly transmits.

“Fig. 12” displays the 2-D modeling of the VLF-EM and the geoelectric section along Traverse 8. The 2-D

model identifies a highly resistive body suspected to be an outcropping basement at 25 m; and water filled

geological formation with a highly weathered/fractured zone between distances 48 and 75 m and 10 and 40 m

respectively. The depth of this strongly conductive target ranges between 0 and 35 m. The zone will be good for

groundwater development.

Figure 10: Bar-Chat of Curve Types obtained from the Study Area



(a)

(b)

Figure 11: (a) 2-D modeling; (b) Geoelectric section along Traverse 2

(a)

(b)


20 40 60 80

320

325

330

335

Dep

th (

m)

Distance (m)

VES 6 VES 7

W E

199

575

52

3061

10

0

5 m

10 m

LEGEND

Partly Weathered Layer/Fracture Basement

Top soil

Fresh Basement

Resistivity785

Laterite Weathered Layer

( -m )

1644

283

136

661

20 40 60 80 100 120 140 160 180

310

315

320

325

330

335

340

345

Dep

th (m

)

171

VES 22 VES 23

VES 24

SW NE

141

719

1406

40

376

60219

1474

562

84

327

270

64

522

5 m

LEGEND

Weathered Layer 64Top soil

Partly Weathered Layer/Fractured Basement

Fresh Basement

Resistivity ( -m )20 m

Existing Borehole Location 4

0



The geoelectric section “Fig. 12b” along this Traverse revealed that weathered layer and the fractured basement

(unconfined) constitute the major aquifers as evidenced by the existing boreholes under VES 24 with resistivity that

ranges between 64 Ω-m and 562 Ω-m; and 40 Ω-m and 522 Ω-m respectively. The composition of the weathered

layer is predominantly clayey sand. The thickness of the weathered layer varies from 5 m to 50 m.

The 2-D structure of the real component of the VLF – EM along Traverse 10 is shown in “Fig.13a”. The 2-

D structure reveals a strongly conductive zone suspected to be water filled geological formation with a highly

weathered /fracture zone at distances between 70 and 115 m. The 2-D also identified a very poor conductive zone

typical of lateritic hard pan between distances 10 and 60 m. Both have a depth extent greater than 20 m. The 2-D

model corroborates the thickly weathered layer (with thickness greater than 20 m) under VES 29 but thin under VES

28. The resistivity of this weathered layer which constitutes the major aquifer unit along this Traverse varies from 28

Ω-m to 229 Ω-m

“Fig. 14” displays the 2-D structure of the real component of the VLF-EM and the geoelectric section along

Traverse 12. The top of the main conductive target (at distance 80 m) as indicated by the 2-D model correlates with

the geoelectric section “Fig. 14b” which identifies this target as a low resistivity (< 50 Ω-m) suspected to be a clayey

material.

The 2-D structure of the real component of the VLF – EM along Traverse 21 is shown in “Fig. 15a”. It

identifies a strongly conductive feature suspected to be water filled geological formation/weathered zone or

fractured zone at distances between 15 m and 45 m. This conductive target has a depth extent of 25 m. The

geoelectric section delineates this feature as a low resistivity geomaterial composed of clay weathered layer and

clayey sand as the topsoil. Therefore, the aquifer unit along this Traverse is clay with resistivity that is generally less

than 100 Ω-m.

“Fig. 16” displays the 2-D structure of the real component of the VLF-EM and the geoelectric section along

Traverse 25. The 2-D “Fig. 16a” model identifies a strongly conductive cross cutting linear feature at distance 400

m. This conductive target has a depth extent greater than 60 m. The presence of this cross cutting linear structure is

indicative of weak/incompetent geologic formation. However, on the geoelectric section beneath VES 66 where this

cross cutting feature occurred, it‟s revealed as fractured basement at a shallow depth (less than 10 m).

IV. CONCLUSIONS Geophysical investigation of Rufus Giwa of Rufus Giwa Polytechnic has been carried out, with the aim of

evaluating the groundwater potential of the institution. The 2-D modeling real component of the VLF-EM revealed

the presence of conductive zones which were used as data points for the vertical electrical soundings. The

geoelectric section revealed 3 to 5 major layers comprising the topsoil, clay, laterite, weathered layer, partly

weathered layer/fractured basement, and fresh basement rock. The weathered layer and fractured basement aquifers

correlate with the suspected water filled geologic formation as lineated by the VLF-EM. Therefore the area has a

good prospect for groundwater development.

REFERENCES [1] A.F. Abimbola, O.M Ajibade, A.A. Odewande, W.O. Okunola, T.A. Laniyan, and T.T. Kolawole, Hydrochemical Characterization of

Water Resources around the Semi-Urban Area of Ijebu-Igbo Southwestern, Nigeria. Journal of Water Resources Vol.20, 2008, 10-15.

[2] R. Barker, L. Blunt, and I. Smith, Geophysical consideration in the design of U.K. National Sounding Database. First Break, Vol. 14,

1996, No. 2, pp. 45-53. [3] A.E. Edet, and O.E. Offiong, Surface Water Quality Evaluation in Odukpani, Calabar Flank, Southwestern, Nigeria. Journal of

Environmental Geology, 36 (3/4), 1998b: 343–348.

[4] R.A. Freeze, and J.A. Cherry, Groundwater (Prentice-Hall, Englewood Cliffs, New Jersey, 1979), 604. [5] Geological Survey of Nigeria, Geological map of Akure Area, Sheet 61. Geological Survey Department, Ministry of Mines, Power

and Steel, Nigeria. 1966.

[6] N.P. Iloeje, A new geography of Nigeria (New Revised Edition) Longman Nig. Ltd., Lagos, 1981, 201pp. [7] KHFFILT, Karous-Hjelt and Frazer filtering of VLF measurements, Version 1.1a, Markku Pirttijarvi, 2004.

[8] Ondo State Surveys Akure, Nigeria. Administrative map of Ondo State, Ministry of works and Housing, Akure Ondo State, Nigeria,

1998. [9] E. Orellana, and H.M. Mooney, Master Tables and Curves for Vertical Electrical Sounding over Layered Structure, Geophy. Prospect

29, 1966: 932-955.

[10] B.P.A Vander Velper, Resist Version 1.0, M.Sc. research Project ITC Delf. Netherlands, 1988.



(a)

(b)


(a)

(b)


40 60 80 100

310

315

320

325

330

335

De

pth

(m

)

Distance (m)

VES 28 VES 29

SW NE

331

50

229

16

2498

82726

46

284

0

5 m Partly Weathered Layer/Fracture Basement

Fresh Basement

20 m Top soil Weathered Layer

58 Resistivity ( -m )

LEGEND

30 35 40 45 50 55 60 65 70 75 80 85 90

300

310

320

De

pth

(m

)

Distance (m)

VES 31VES 32

51683

14979

19

3941

651258

20

14478

LEGEND

Resistivity


ClayTop soil

Fresh Basement

5 m

10 m

0

( -m)19



(a)

(b)


(a)

(b)


20 40 60 80 100 120 140 160 180 200 220 240 260

290

300

310

320

330

Dept

h (m

)

VES 52

VES 53 VES 54369

251

93

17578

538305

38

105

278240

Distance (m)W E

Weathered Layer

Fresh Basement

20 m

10 m

0

105 Resistivity ( -m )

Top Soil


50 100 150 200 250 300 350 400 450 500 550

280

300

320

340

Dep

th (m

)

VES 64VES 65

VES 66 VES 67

Distance (m)

229

247 302 627

936618501

901

207

163252

355

907 752

914

7581

Fresh Basement

50 m LEGEND

Weathered Layer

Resistivity


20 m

Top soil Laterite

252 ( -m )

W E

0

Geophysical Investigation for Groundwater Potential in Rufus Giwa Polytechnic Owo, Southwestern...

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