Research Article Assessment of Economically …downloads.hindawi.com/archive/2014/578981.pdfResearch Article Assessment of Economically Accessible Groundwater Reserve and Its Protective

Research ArticleAssessment of Economically Accessible GroundwaterReserve and Its Protective Capacity in Eastern Obolo LocalGovernment Area of Akwa Ibom State Nigeria UsingElectrical Resistivity Method

N J George1 E U Nathaniel1 and S E Etuk2

1 Department of Physics Akwa Ibom State University Ikot Akpaden 53001 Nigeria2 Department of Physics University of Uyo Uyo 53001 Nigeria

Correspondence should be addressed to N J George nyaknojimmyggmailcom

Received 30 December 2013 Accepted 27 February 2014 Published 14 April 2014

Academic Editors E Liu G Mele F Monteiro Santos and B Tezkan

Copyright copy 2014 N J George et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The application of geophysical method employing vertical electrical sounding (VES) method in combination with laboratoryanalysis of aquifer sediments has been used to access the economically accessible groundwater reserve and its protective capacityin some parts of Eastern Obolo Local Government area the eastern region of the Nigerian Niger Delta Schlumberger electrodeconfiguration was used to sound twelve VES to occupy the areas that have borehole locations and accessibility for the spread ofcurrent electrodes to at least 1000m Based on the results the safe and economic aquifer potential has groundwater reserve ofabout 168480558 plusmn 18532861m3 The desired aquifer thickness and its depth of burial have average value of 5202m and 7314mrespectively The area has a fair protective capacity This is indicated by 5833 weak 1667 moderate and 25 good protectivecapacity for the areaThis study was done in one of the oil cities where contaminated Salt River water is used as the major source ofwater for domestic uses and it is believed that the settlers will appropriate this result and sue for safe groundwater at the indicateddepths

1 Introduction

The need to assess safe groundwater repositories is increas-ingly important in Eastern Obolo Local Government Area(EOLGA) located in Eastern Niger Delta region of Nige-ria because of the extant health hazards posed by surfaceand underground contaminations which are associated withchemical microbial and physical contaminant plumes Thefocus of groundwater quality protection is on the preventionof groundwater pollution however where groundwater hasbecome polluted it must be cleaned up and managed toensure the ongoing protection of human health and theenvironment Access to clean water is a human right andbasic requirement for economic development The world-wide development of past civilisations as well as the recentsocioeconomic evolution of nations is based on and strongly

controlled by the availability of water which can be obtainedeither as surface or subsurface water

The Niger Delta region (the site for which the studyarea is located) is one of the most industrialised parts inthe entire Gulf of Guinea These industries have contributedimmensely to economic growth and development of thestates within the region The region which is one of the tenmost important wetland and marine ecosystems in the worldhas suffered immensely from these unsustainable industrialactivities [1] Some of the human activities that have impactednegatively on the Niger Delta environment include industrial(hydrocarbon exploration and exploitation noise pollutiongas flaring oil spillage and waste disposal) removal of back-shore vegetation construction of barges and other coastalcontrol works river dredging agricultural (excessive anduncontrolled application of inorganic fertilizers pesticides

Hindawi Publishing CorporationISRN GeophysicsVolume 2014 Article ID 578981 10 pageshttpdxdoiorg1011552014578981

2 ISRN Geophysics

Sandy formation

Rive

rs S

tate

Ikot Abasi

Alluvium

SiltstoneBH

1

1 1

2

20

3

4

5

67

8

9

10

11

12

A

B

C

D

E

F

Nigeria

N

BH

BH

BH

BH

(km)

BH

BH

BH BH

BH

BH

BH

BH

BH

Atabrikang Aquaha

Atabrikang Ekeme

Bight of Bonny Onna

Okoro EteIko town

Okoro Inyang

Queen townKalasunju

Opobo town

Obianga

Okpukalama

Mkpat Enin

State boundary

Major roadMinor road

TributaryLGA boundaryRiver

LGA headquartersSettlementVES station VES traverseA B

7∘30

998400E 7∘32

998400E 7∘34

998400E 7∘36

998400E 7∘38

998400E 7∘40

998400E 7∘42

998400E

7∘30

998400E 7∘32

998400E 7∘34

998400E 7∘36

998400E 7∘38

998400E 7∘40

998400E 7∘42

998400E

4∘30

998400N

4∘32

998400N

4∘25

998400N

4∘20

998400N

4∘15

998400N

Figure 1 Location map showing the study location VES points and VES traverses

and herbicides) municipal waste disposal urbanisation andmining activities [2 3] Environmental problems like lossof biodiversity coastal and riverbank erosion flooding landdegradation loss of soil fertility and deforestation are nowcommon [1 4] Most of the numerous surface water resourceendowments of the area which the entire population usedto be solely dependent on for their domestic agriculturalindustrial and social needs are currently seriously pollutedby both natural and anthropogenic sources [4] Recently theactivities of criminals who are involved in illegal pipelinevandalism and crude oil theft and refining have compoundedthe environmental problems in the Niger Delta region Thequality of the groundwater resources in many parts of theregion is gradually being degraded [5]There is urgent need tounderstand the extent of natural protection the distributionsof the economically safe aquifer repository and possibly thepollutant flow path in order to design appropriate mitigationremediation and protection strategies especially now thatsuch plans are in the drawing board by governmentalenvironmental and other international partners Designof appropriate groundwater management strategies in anygeologic environment depends to a reasonable extent on thenature of subsurface materials whose properties (physicaland chemical) and spatial distribution constitute the goalof all hydrogeological and hydrogeophysical investigationsThe surface water is found to be grossly degraded in qualitybecause of its exposure to physical biological or chemicalcontaminants [6] Groundwater on its own has less degreeof contaminations when relatively compared with surface

water Inadequate public water supply has led to increaseddemand for alternative sources of water supply in EOLGAdue to rapidity in human growth in recent times [7] Todaywe are witnessing the increasing number of boreholes drilledby the government nongovernmental organizations andindividualsThis clearly shows that groundwater is effectivelycomplementing other sources of water supply in the areaThis is due to the rate of contamination of surface waterthrough the effect of inordinate quest for developmentWildcat drilling which does not support any scientific searchfor the location of the water bearing sediments in the areahas exposedmany groundwater resources to contaminationsIn view of this the area was mapped in order to access thequantitative reserve distribution of the safe and economicwater bearing units its depth of burial and the protectivecapacity of the groundwater repositories in the study area

2 Location and Geology of the Study Area

The study area shown in Figure 1 lies between longitudes7∘301015840 and 7∘ 421015840 E and latitudes 4∘151015840 and 4∘321015840N in the NigerDelta region of Southern Nigeria The study was designedto cover some areas of Eastern Obolo Local GovernmentAreas of Akwa Ibom State of Nigeria one of the oil richregions of the Arcuate Niger Delta surrounded by both freshand saline water The study area is located in an equatorialclimatic region that is characterised by two major seasonsThe seasons are the rainy season (MarchndashOctober) anddry season (NovemberndashFebruary) [7 8] The dry season is

ISRN Geophysics 3

a period of extreme aridity characterized by excruciatinghigh temperatures that do reach 35∘C The area has beenseverely affected by the current global climatic changes insuch a way that there have been shifts in both the upperand lower boundaries of these climatic conditions [9ndash13]Thestudy area is located in the tertiary to quaternary coastal plainsands (CPS) (otherwise called the Benin Formation) andalluvial environments of the Niger Delta region of SouthernNigeria (Figure 1) The Benin Formation which is underlainby the paralic Agbada Formation covers over 80 of thestudy area The sediments of the Benin Formation consistof interfringing units of lacustrine and fluvial loose sandspebbles clays and lignite streaks of varying thicknesseswhile the alluvial units comprise tidal and lagoonal sedimentsand beach sands and soils [14ndash16] which are mostly foundin the southern parts and along the river banks The CPS iscovered by thin lateritic overburden materials with varyingthicknesses at some locations but is massively exposed nearthe shorelines The CPS forms the major aquiferous unitsin the area It comprises poorly sorted continental (finemedium and coarse) sands and gravels that alternatewith lig-nite streaks thin clay horizons and lenses at some locationsThe thin clayshale horizons truncate the vertical and lateralextents of the sandy aquifers thereby building upmultiaquifersystems in the area [17] Thus both confined and partiallyconfined aquifers can be found in the area Southward flowingrivers like the Kwa River and their tributaries that emptydirectly into the Bight of Bonny drain the area

3 Data Acquisition and Analysis

Surface electrical methods have been used in investigatingdifferent types of geological geotechnical and environmentalproblems for many years due to the dependence of earthresistivity on some geologic parameters Generally the elec-trical resistivity method involves injecting electrical currentinto the ground through a pair of electrodes (called currentelectrodes) and monitoring the potential difference createdby the passage of the electrical current through the earthmaterials using another pair of electrodes technically calledpotential electrodes Details of this can be found in [18ndash20] Many electrode configurations and field procedures existthat can be used to perform geoelectrical investigations [18]but the Schlumberger array which was performed using thevertical electrical sounding field procedure was adopted toassess the subsurface electrical resistivity and the depth ofthe economically accessible aquifers The Schlumberger elec-trode configuration used in measuring apparent resistivity 120588

119886

is shown in the following equation

120588119886= 120587 sdot ((1198601198612)

2minus (1198721198732)

2

(119872119873)) sdot 119877119886 (1)

whereAB is the distance between two current electrodes119872119873is the distance between two potential electrodes and 119877

119886is

the apparent electrical earthrsquos resistance measured from the

equipment The term in the equation shown below is calledthe geometric factor (119866)

119866 = 120587 sdot ((1198601198612)

2minus (1198721198732)

2

119872119873) (2)

The electrical resistivity investigations were conducted intwelve (12) locations across the study area between 2011 and2012 using a SAS1000model of ABEMTerrameterMaximumcurrent electrode spacing (119860119861) was constrained by settlementpattern and other space limiting conditions to vary fromone location to another This confined the VES points tothe locations shown in Figure 1 In locations with goodaccess paths andor roads the current cables were extendedup to 1000m in order to ensure that depths above 200mwere comfortably sampled assuming that penetration depthvaries between 025119860119861 and 05119860119861 [21 22] Correspondingreceiving (potential) electrode separation (119872119873) varied froma minimum of 05m at119860119861 = 2m to a maximum of 50mat119860119861 = 1000m At all the electrode positions great care wastaken to ensure that the separation between the potentialelectrodes did not exceed one-fifth of the separation of thecurrent electrodes [23] VES data quality was generally goodespecially in the wet season but in the dry season theelectrode positions were usually wetted with water and saltsolution (where necessary) in order to lower the contactresistance and consequently ensure good electrical contactbetween the ground and the steel electrodes

Information generated from the analyses of geophysicaldata was used to constrain drillingThe drilling phase startedas soon as the geophysical reports were submitted to theAkwa Ibom State Millennium Development Goal [24] thatfunded the borehole projects Manual drilling technique wasadopted in drilling 6-inch borehole in all locations since thesubsurface condition in the entire area was favourable to suchdrillingmethod Some of the boreholes were cited adjacent tothe VES stations while some that are located at where therewas no access path to spread the cables at the vicinity of theboreholes were separated by more than 150m (see Figures2 3 and 4) The drill cuttings were logged geologically inall 12 locations and from the desired aquifer samples werecollected for laboratory measurement of porosityThe drilledboreholes were cased using 75mm high pressure PVC casingmaterials The PVC casings were slotted at various depthswith sizable thicknesses and the slotted region of the wellannulus was gravel packed to ensure good delivery of water tothe borehole Gravel packing is also important in checking theingress of sediments into the borehole Amixture of sand andcement was used to grout the boreholes to prevent backflowof water at the surface into the well [25] The wells weredeveloped

The core samples were prewashed with distilled waterto remove traces of clay and other argillaceous materialsthat might have originated from the coring operation [26]The samples were later put into a vacuum desiccator andevacuated at a pressure of 03mBar for a period of 1 hour (see[27]) Deaerated distilled water was gently poured into thedesiccator until the water completely covers all the samplesAll the samples were later soaked for a period of 24 hours

4 ISRN Geophysics

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 4

VES 1

Half current electrode configuration [AB2] (m)

(a)

10

20

30

50

60

40

70

80

RMSEBH BH

24 25 NANA

VES

4

VES

1

6804 9499

14886 27155

14645

5492

37452

12487

Gra

velly

sand

Gra

velly

sand

Pene

trat

ion

dept

h (m

)

Loamy

Fine

sand

Fine

sand

topsoilLoamytopsoil

(b)

Figure 2 Samples of modelled VES curves along119860119861 profile showing correlations between VES derived 1-D subsurface models and boreholelithologs

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 5

VES 7


Resis

tivity

(Ωm

)

(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

RMSE 21 NA 25 NA

VES

5

VES

7

BH BH

7184

18449

2058

7503

Sandytopsoil

Fine

sand

Gra

velly

sand

Silts

tone

Fine

sand

13622

14408

526

668

Loamytopsoil

(b)

Figure 3 Samples of modelled VES curves along CD profile showing correlations between VES derived 1-D subsurface models and boreholelithologs

ISRN Geophysics 5

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 12

VES 10


(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

90

100

110

NA not applicable

RMSE root-mean square error

VES

12

26

12410

1182

6112

48930

26

2107

3979

17214

2282

RMSE NA NA

VES

10

BH BH

Silts

tone

Fine

sand

Fine

sand

Silts

tone

Loamytopsoil

Loamytopsoil

(b)

Figure 4 Samples of modelled VES curves along EF profile showing correlations between VES derived 1-D subsurface models and boreholelithologs

in order to ensure that any trace of salt and other relatedsoluble contaminants within the samples diffused out intothe surrounding water The cleaned samples were later driedin a temperature controlled oven at 105∘C for 16 hours inorder to check any irreversible change in the composition ofthe samples (see [27 28]) The oven dried core samples wereallowed to cool to normal air temperature in a desiccatorTheweight of the cool and dry core samples 119882

119889was measured

using an electronic weighing balance five times and the meanwas computed and recorded The samples were soaked withdistilled water that has been boiled for 30 minutes in avacuum pressure of 03mBar for 18 hours The weight of thewet samples119882

119908was also measured five times and the mean

was computed and recorded Effective porosity (120601) of thesamples was calculated using (6) as

120601 = 100 sdot (119882119908minus119882119889

119881) (3)

where119881 is volume of the samples Details of the experimentalprocedure can be found in [26ndash28]

4 Results and Discussion

The field data consisting of the apparent resistivity (120588119886) and

the current electrode spacing (1198601198612) were partially curvematched smoothened and manually plotted against eachother on a bilogarithmic scale with 120588

119886on the ordinate and

current electrode 1198601198612 on the abscissa It was performedby either averaging the two readings at the crossover pointsor deleting any outlier at the crossover points that did notconform to the dominant trend of the curve Also deletedwere data that stood out as outliers in the prevalent curvetrend which could have caused serious increase in root meansquare error (RMSE) during themodelling phase of the workWhere observed such outliers constitute less than 2 of thetotal data generated in each sounding station and since wemeasured over ten data per decade deleting such noisy datadid not alter the trend of the sounding curve Some of thedeleted data might have been the electrical signatures of thethin clay materials that might have suffered suppression fromthe over- and underlying thick sandy aquifers [29 30] Anydiscontinuity observed in the smoothened curves was exclu-sively attributed to vertical variation of electrical resistivitywith depth Preliminary interpretation of the smoothenedcurves wasmade using the traditional partial curvemarchingtechnique to estimate primary layer parameters The partialcurve matching technique uses master curves and chartsdeveloped by [31] A computer basedVESmodelling softwarecalled RESIST [32] that can perform automated approxima-tion of the initial resistivity model from the observed datawas later used to improve upon the preliminary interpretedresults using the inversion technique The RESIST softwareuses the initial layer parameters to perform some calculationsand at the end generates a theoretical curve in the process Itthen compares the theoretical curve with the field data curve

6 ISRN Geophysics

Table1Summaryof

locatio

ncoordinatesgeoelectric

allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7

Table 2 Protective capacity ratings of longitudinal conductance

Range Strength119878 gt 10 Excellent5 lt 119878 lt 10 Very good07 lt 119878 lt 49 Good02 lt 119878 lt 069 Moderate01 lt 119878 lt 019 Weak119878 lt 01 Poor

Since quantitative interpretation of geoelectrical soundingdata is usually difficult due to the inherent problem ofequivalence [33] borehole data were used to constrain alldepth andminimise the choice of equivalentmodels by fixinglayer thicknesses and depths while allowing the resistivitiesto vary [34] The total number of observed minima andmaxima on the smoothened VES curves was usually usedas the starting number of layers (or models) over a half-space for the data inversion exercise The software worksiteratively by calculating at the end of each step updatedparameters of the model and calculates the extent of fitbetween the calculated and the observed data using theroot mean square error (RMSE) technique in which 5 waspreset as the maximum acceptable value Figures 2 3 and 4show some of the modelled VES curves observed andtheir correlation between the nearby borehole lithology andinterpreted results A good correlation was observed betweenthe borehole lithology log data and the inverted results overhalf-space in many locations These noticed distortions weresuspected to have possibly originated from the failure of the1D assumption of the shallow subsurface of the half-space[29] The result of the computer iterations gave the layers ofthe subsurface penetrated by current true resistivity of eachlayer the thickness (ℎ) depth (119889) of each layer and the totaldepth of overburden to the safe and economically accessibleauriferous layers as shown in Table 1 Three to four layerswith different curve types were delineated The availabilityof H and K curve types indicates the high and low valuesof resistivities in sediments which translate from unsaturatedzones into saturated zones Specifically the curve types inthe areas occupied by VES are KH which takes 417 K HAH AK and QH which respectively take 83 of the totalcurve distributions The other curve type also noticed is theAH curve type which takes 167 of the curve distributions(see Table 1 and Figure 5 for curve distributions) From theinferred layer resistivities and thicknesses the longitudinalconductance known as one of the Dar Zarrouk parameterswas used to classify the degree of protection of each of VESsites according to rating in Table 2 intoweakmoderate goodand excellent aquifers based on the numerical values assignedto each point Based on the longitudinal conductance theprotective capacity of the overburden showed that 5833 ofthemapped area has weak protective capacity 1667moder-ate protective capacity and 25goodprotective capacityThisis an indication that the chosen economic aquifer repositoryapart from having a sizeable thickness of average value of5205m and average depth of 7314m also has a fair protection

0

10

20

30

40

Curv

e fre

quen

cy (

)

KH K H HA AH AK QHCurve type

417

833 833

167

833 833 833

Figure 5 Bar chart showing frequency of curve type distribution inthe study area

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0

North of reference coordinate (m)

Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500

Figure 6 Distribution of longitudinal conductance map showinghigh values of S in VES 6 7 and 8 in the north-eastern zone of themapped area

from the surface flow despite its open nature The sizeablethickness and the average depth of the aquifer located inaquifer units ranging from fine sand to coarse or in siltstonecan be economically exploited for domestic and industrialuses by the settlers of the region

The longitudinal conductance (119878) is given by

119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883

+ sdot sdot sdot +ℎ119899

120588119899

(4)

where ℎ119894and 120588

119894are the saturated thickness of each of the

layers and their corresponding true resistivities respectivelyThe earthrsquos medium acts as a natural filter to percolatingfluid The ability of the earth to retard or accelerate and filterpercolating fluid is a measure of its protective capacity [3536] The total longitudinal conductance is a parameter usedto define the target areas of groundwater potential High 119878values indicate relatively thick geologic succession and shouldbe accordedwith the highest priority in terms of groundwaterpotential while low 119878 reflects thin geologic successions withlow groundwater potential [35] The contour map showing 119878distribution is given in Figure 6

The results of the thickness and total depth of groundwa-ter repository in Table 1 were respectively used in generatingthe 2D and 3D representation of the subsurface economicgroundwater repository and 3Dmap showing the total depth

8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0

East of reference coordinate (m)1000 1500500

Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30

North reference coordinates (m) East of reference

coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)

Figure 7 (a) 2D distribution of aquifer thickness in the mapped area (b) 3D distribution map of the preferred aquifer thickness in themapped area used in computing the groundwater reserve

1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90

North of reference coordinates (m)East

of refer

ence

coordinate

s (m)

Dep

th (m

)

Depth to aquifer (m)70100

50

Figure 8 3D distribution map of depth to aquifer in the mappedarea

in a continuum (see Figures 7(a) 7(b) and 8) ApplyingSURFER programme to the thickness geometry the totalvolume of the unconfined aquifer geometry was computedas 576396025m3and the porous volume based on the averageporosity of the unconfined aquifer of 2923 (02923) was168480558m3 using the latitude of each of the survey lines asthe119910-axis and the longitude as119909-axis The porosity distribu-tion was also produced using fractional porosities in Table 1and the porosity variation is shown in Figure 9 These mapsdescribe the variations of the aquifer and can explain the flowpattern of groundwater The thickness of the economic andsafe aquifer repository to the estimated depth was consideredas the z-axisThe error in porous volumewas computed usingthe equation below

Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)

where Δ119881 Δ119897 Δℎ Δ119908 120601 and Δ120601 are error in volumeV errorin length 119897(0) error in thickness ℎ(0) error in width119908 and

9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023

East of reference coordinate (m)1000 1200 1400400200 600 800

Frac

tiona

l por

osity

02

Figure 9 3D distribution map of porosity of the preferred aquiferin the mapped area

error in porosity The error in length and width is negligibleHence

Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)

Therefore the approximate volume of porous zone is 2923of the considered aquifer total volume Hence there exists168480558plusmn18532861m3 of water residing in the study area

5 Conclusion

The inferred safe and economic aquifer repository locatedin fine to gravelly sands does not show any interaction inthe reference location based on the resistivity the converseof conductivity The estimated reserve shows that moreboreholes can be drilled to exploit the described aquifer sothat the reasonable population who relies on the Salt Riverwater in the area can avoid the biological chemical andphysical adverse consequences associated with river water

ISRN Geophysics 9

The protection of the aquifer based on the overburden mate-rials is commendable as the area has on the average goodaquifers mostly within the vicinity of VES 6ndash12 Laboratorychecks can be conducted from time to time in order toaccess the protective capacity of aquifers within the regionsof VES 1ndash5 described as weak The average depth of theoverburden to the aquifer repository the highly resistivetopsoil and estimated protective capacity on the averageindicate that the safe economically recommended aquifer canbe free from surface or near-surface contaminant plumesThe porosity longitudinal conductance thickness and depthto aquifer distribution maps drawn could be used to deriveinput parameters for contaminant migration modelling andto improve the quality of model The method is unique asthe calculated aquifer parameters are well defined within therange of observed aquifer parameters

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] A A Kadafa ldquoOil exploration and spillage in the Niger Delta ofNigeriardquo Civil and Environmental Research vol 2 no 3 pp 38ndash51 2012

[2] H I Ezeigbo and B N Ezeanyim ldquoEnvironmental pollutionfrom coal mining activities in the Enugu area Anambka stateNigeriardquoMineWater and the Environment vol 12 no 1 pp 53ndash61 1993

[3] A E Edet and C S Okereke ldquoA regional study of saltwater in-trusion in southeastern Nigeria based on the analysis of geo-electrical and hydrochemical datardquo Environmental Geology vol40 no 10 pp 1278ndash1289 2001

[4] United Nations Environmental Programme ldquoEnvironmentalassessment of Ogonilandrdquo Executive Summary UNEP 2011

[5] K S Okiongbo and E Akpofure ldquoDetermination of aquiferproperties and groundwater vulnerability mapping using geo-electricmethod in Yenagoa city and its environs in Bayelsa stateSouth Nigeriardquo Journal of Water Resource and Protection vol 4no 6 pp 354ndash362

[6] A Edet and R H Worden ldquoMonitoring of the physical param-eters and evaluation of the chemical composition of river andgroundwater inCalabar (SoutheasternNigeria)rdquoEnvironmentalMonitoring and Assessment vol 157 no 1ndash4 pp 243ndash258 2009

[7] N J George A E Akpan and I B Obot ldquoResistivity study ofshallow aquifers in the parts of Southern Ukanafun Local Gov-ernment Area Akwa Ibom state Nigeriardquo E-Journal of Chem-istry vol 7 no 3 pp 693ndash700 2010

[8] U F Evans N J George A E Akpan I B Obot and A N IkotldquoA study of superficial sediments and aquifers in parts of UyoLocal Government Area Akwa Ibom state Southern Nigeriausing electrical sounding methodrdquo E-Journal of Chemistry vol7 no 3 pp 1018ndash1022 2010

[9] A G Martınez K Takahashi E Nunez et al ldquoA multi-institu-tional and interdisciplinary approach to the assessment of vul-nerability and adaptation to climate change in the PeruvianCentral Andes problems and prospectsrdquo Advances in Geo-sciences vol 14 pp 257ndash260 2008

[10] D Rapti-Caputo ldquoInfluence of climatic changes and human ac-tivities on the salinization process of coastal aquifer systemsrdquoItaian Journal of Agronomy vol 3 pp 67ndash79 2010

[11] E S Riddell S A Lorentz andD C Kotze ldquoA geophysical anal-ysis of hydro-geomorphic controls within a headwater wetlandin a granitic landscape through ERI and IPrdquo Hydrology andEarth System Sciences vol 14 no 8 pp 1697ndash1713 2010

[12] GWagner and R J Zeckhauser ldquoClimate policy hard problemsoft thinkingrdquo Climatic Change vol 110 no 3-4 pp 507ndash5212012

[13] B K Farauta C L Egbule A E Agwu Y L Idrisa and N AOnyekuru ldquoFarmersrsquo adaptation initiatives to the impact of cli-mate change on agriculturein Northern Nigeriardquo Journal of Ag-ricultural Extension vol 16 no 1 pp 132ndash144 2012

[14] T J A Reijers SW Petters and C S Nwajide ldquoTheNiger deltabasinrdquo in African Basins R C Selley Ed vol 3 of SedimentaryBasin of the World pp 151ndash172 Elsevier Science AmsterdamThe Netherlands 1997

[15] T J A Reijers and S W Petters ldquoDepositional environmentsand diagenesis of Albian carbonates on the Calabar Flank SENigeriardquo Journal of Petroleum Geology vol 10 no 3 pp 283ndash294 1987

[16] T N Nganje A E Edet and S J Ekwere ldquoConcentrations ofheavymetals and hydrocarbons in groundwater near petrol sta-tions and mechanic workshops in Calabar metropolis South-eastern Nigeriardquo Environmental Geosciences vol 14 no 1 pp15ndash29 2007

[17] N J George A I Ubom and J I Ibanga ldquoIntegrated approachto investigate the effect of leachate on groundwater around theIkot Ekpene dumpsite in Akwa Ibom state Southeastern Nige-riardquo International Journal of Geophysics vol 2014 Article ID174589 12 pages 2014

[18] WMTelford L P Geldart R E Sheriff andDAKeysAppliedGeophysics Cambridge University Press 2nd edition 1990

[19] G V Keller and F C Frischknecht Electrical Methods in Geo-physical Prospecting Pergamon London UK 1966

[20] M S Zhdanov and G KellerThe Geoelectrical Methods in Geo-physical Exploration Methods in Geochemistry and Geo-physics Elsevier 1994

[21] K K Roy andHM Elliot ldquoSome observations regarding depthof exploration in DC electrical methodsrdquo Geoexploration vol19 no 1 pp 1ndash13 1981

[22] K P Singh ldquoNonlinear estimation of aquifer parameters fromsurficial resistivity measurementsrdquoHydrology and Earth SystemSciences vol 2 pp 917ndash938 2005

[23] S S Gowd ldquoElectrical resistivity surveys to delineate ground-water potential aquifers in Peddavanka watershed AnantapurDistrict Andhra Pradesh Indiardquo Environmental Geology vol46 no 1 pp 118ndash131 2004

[24] Akwa Ibom State Millennium Development Goal (AKSMDG)ldquoBorehole completion report from the thirty one Local Govern-ment Areas of Akwa Ibom Staterdquo Tech Rep 2011

[25] A C Ibuot G T Akpabio and N J George ldquoA survey of therepository of groundwater potential and distribution using geo-electrical resistivity method in Itu Local Government Area(LGA) Akwa Ibom State SouthernNigeriardquoCentral EuropeanJournal of Geosciences vol 5 no 4 pp 538ndash547 2013

[26] American Petroleum Institute (API) ldquoRecommended practicefor core analysis procedurerdquo Tech Rep no 40 1990

[27] DW Emerson ldquoLaboratory electrical resistivityrdquo Proceedings ofthe Australian Institute of Mining and Metallurgy vol 230 no51 1969

10 ISRN Geophysics

[28] J S Galehouse ldquoSedimentation analysisrdquo in Procedures in Sedi-mentary Petrology R F Carver Ed p 653 Wiley-InterscienceNew York NY USA

[29] V V S G Rao G T Rao L Surinaidu R Rajesh and JMaheshldquoGeophysical and geochemical approach for seawater intrusionassessment in the Godavari Delta Basin AP IndiardquoWater Airamp Soil Pollution vol 217 no 1ndash4 pp 503ndash514 2011

[30] M A Sabet ldquoVertical electrical resistivity sounding locategroundwater resources a feasibility studyrdquoWater Resources Bul-letin vol 73 p 63 1975

[31] E Orellana andAMMooneyMaster Curve and Tables for Ver-tical Electrical Sounding over Layered Structures IntercienciaEscuela Spain 1966

[32] B P A V Velpen ldquoA computer processing package for DC re-sistivity interpretation for an IBM compatiblesrdquo ITC Journalvol 4 1988

[33] R A van Overmeeren ldquoAquifer boundaries explored by geo-electrical measurements in the coastal plain of Yemen a case ofequivalencerdquo Geophysics vol 54 no 1 pp 38ndash48 1989

[34] A T Batayneh ldquoA hydrogeophysical model of the relationshipbetween geoelectric and hydraulic parameters Central JordanrdquoJournal of Water Resource and Protection vol 1 pp 400ndash4072009

[35] R Barker T V Rao and M Thangarajan ldquoDelineation of con-taminant zone through electrical imaging techniquerdquo CurrentScience vol 81 no 3 pp 277ndash283 2001

[36] A O Olawepo A A Fatoyinbo I Ali and T O Lawal ldquoEvalua-tion of groundwater potential and subsurface lithologies inUni-lorin quarters using resistivity methodrdquo The African Review ofPhysics vol 8 pp 317ndash323 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of


EarthquakesJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining


Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of


Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering


GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of


OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in


MineralogyInternational Journal of


MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Geological ResearchJournal of


Geology Advances in

2 ISRN Geophysics

Sandy formation

Rive

rs S

tate

Ikot Abasi

Alluvium

SiltstoneBH

1

1 1

2

20

3

4

5

67

8

9

10

11

12

A

B

C

D

E

F

Nigeria

N

BH

BH

BH

BH

(km)

BH

BH

BH BH

BH

BH

BH

BH

BH

Atabrikang Aquaha

Atabrikang Ekeme

Bight of Bonny Onna

Okoro EteIko town

Okoro Inyang

Queen townKalasunju

Opobo town

Obianga

Okpukalama

Mkpat Enin

State boundary

Major roadMinor road

TributaryLGA boundaryRiver

LGA headquartersSettlementVES station VES traverseA B

7∘30

998400E 7∘32

998400E 7∘34

998400E 7∘36

998400E 7∘38

998400E 7∘40

998400E 7∘42

998400E

7∘30

998400E 7∘32

998400E 7∘34

998400E 7∘36

998400E 7∘38

998400E 7∘40

998400E 7∘42

998400E

4∘30

998400N

4∘32

998400N

4∘25

998400N

4∘20

998400N

4∘15

998400N

Figure 1 Location map showing the study location VES points and VES traverses

and herbicides) municipal waste disposal urbanisation andmining activities [2 3] Environmental problems like lossof biodiversity coastal and riverbank erosion flooding landdegradation loss of soil fertility and deforestation are nowcommon [1 4] Most of the numerous surface water resourceendowments of the area which the entire population usedto be solely dependent on for their domestic agriculturalindustrial and social needs are currently seriously pollutedby both natural and anthropogenic sources [4] Recently theactivities of criminals who are involved in illegal pipelinevandalism and crude oil theft and refining have compoundedthe environmental problems in the Niger Delta region Thequality of the groundwater resources in many parts of theregion is gradually being degraded [5]There is urgent need tounderstand the extent of natural protection the distributionsof the economically safe aquifer repository and possibly thepollutant flow path in order to design appropriate mitigationremediation and protection strategies especially now thatsuch plans are in the drawing board by governmentalenvironmental and other international partners Designof appropriate groundwater management strategies in anygeologic environment depends to a reasonable extent on thenature of subsurface materials whose properties (physicaland chemical) and spatial distribution constitute the goalof all hydrogeological and hydrogeophysical investigationsThe surface water is found to be grossly degraded in qualitybecause of its exposure to physical biological or chemicalcontaminants [6] Groundwater on its own has less degreeof contaminations when relatively compared with surface

water Inadequate public water supply has led to increaseddemand for alternative sources of water supply in EOLGAdue to rapidity in human growth in recent times [7] Todaywe are witnessing the increasing number of boreholes drilledby the government nongovernmental organizations andindividualsThis clearly shows that groundwater is effectivelycomplementing other sources of water supply in the areaThis is due to the rate of contamination of surface waterthrough the effect of inordinate quest for developmentWildcat drilling which does not support any scientific searchfor the location of the water bearing sediments in the areahas exposedmany groundwater resources to contaminationsIn view of this the area was mapped in order to access thequantitative reserve distribution of the safe and economicwater bearing units its depth of burial and the protectivecapacity of the groundwater repositories in the study area

2 Location and Geology of the Study Area

The study area shown in Figure 1 lies between longitudes7∘301015840 and 7∘ 421015840 E and latitudes 4∘151015840 and 4∘321015840N in the NigerDelta region of Southern Nigeria The study was designedto cover some areas of Eastern Obolo Local GovernmentAreas of Akwa Ibom State of Nigeria one of the oil richregions of the Arcuate Niger Delta surrounded by both freshand saline water The study area is located in an equatorialclimatic region that is characterised by two major seasonsThe seasons are the rainy season (MarchndashOctober) anddry season (NovemberndashFebruary) [7 8] The dry season is

ISRN Geophysics 3




119886


120588119886= 120587 sdot ((1198601198612)

2minus (1198721198732)

2

(119872119873)) sdot 119877119886 (1)


119886is



119866 = 120587 sdot ((1198601198612)

2minus (1198721198732)

2

119872119873) (2)




4 ISRN Geophysics

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 4

VES 1


(a)

10

20

30

50

60

40

70

80

RMSEBH BH

24 25 NANA

VES

4

VES

1

6804 9499

14886 27155

14645

5492

37452

12487

Gra

velly

sand

Gra

velly

sand

Pene

trat

ion

dept

h (m

)

Loamy

Fine

sand

Fine

sand

topsoilLoamytopsoil

(b)


105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 5

VES 7


Resis

tivity

(Ωm

)

(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

RMSE 21 NA 25 NA

VES

5

VES

7

BH BH

7184

18449

2058

7503

Sandytopsoil

Fine

sand

Gra

velly

sand

Silts

tone

Fine

sand

13622

14408

526

668

Loamytopsoil

(b)


ISRN Geophysics 5

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 12

VES 10


(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

90

100

110

NA not applicable


VES

12

26

12410

1182

6112

48930

26

2107

3979

17214

2282

RMSE NA NA

VES

10

BH BH

Silts

tone

Fine

sand

Fine

sand

Silts

tone

Loamytopsoil

Loamytopsoil

(b)



119889was measured




120601 = 100 sdot (119882119908minus119882119889

119881) (3)







6 ISRN Geophysics

Table1Summaryof

locatio


allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

ISRN Geophysics 3




119886


120588119886= 120587 sdot ((1198601198612)

2minus (1198721198732)

2

(119872119873)) sdot 119877119886 (1)


119886is



119866 = 120587 sdot ((1198601198612)

2minus (1198721198732)

2

119872119873) (2)




4 ISRN Geophysics

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 4

VES 1


(a)

10

20

30

50

60

40

70

80

RMSEBH BH

24 25 NANA

VES

4

VES

1

6804 9499

14886 27155

14645

5492

37452

12487

Gra

velly

sand

Gra

velly

sand

Pene

trat

ion

dept

h (m

)

Loamy

Fine

sand

Fine

sand

topsoilLoamytopsoil

(b)


105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 5

VES 7


Resis

tivity

(Ωm

)

(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

RMSE 21 NA 25 NA

VES

5

VES

7

BH BH

7184

18449

2058

7503

Sandytopsoil

Fine

sand

Gra

velly

sand

Silts

tone

Fine

sand

13622

14408

526

668

Loamytopsoil

(b)


ISRN Geophysics 5

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 12

VES 10


(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

90

100

110

NA not applicable


VES

12

26

12410

1182

6112

48930

26

2107

3979

17214

2282

RMSE NA NA

VES

10

BH BH

Silts

tone

Fine

sand

Fine

sand

Silts

tone

Loamytopsoil

Loamytopsoil

(b)



119889was measured




120601 = 100 sdot (119882119908minus119882119889

119881) (3)







6 ISRN Geophysics

Table1Summaryof

locatio


allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

4 ISRN Geophysics

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 4

VES 1


(a)

10

20

30

50

60

40

70

80

RMSEBH BH

24 25 NANA

VES

4

VES

1

6804 9499

14886 27155

14645

5492

37452

12487

Gra

velly

sand

Gra

velly

sand

Pene

trat

ion

dept

h (m

)

Loamy

Fine

sand

Fine

sand

topsoilLoamytopsoil

(b)


105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 5

VES 7


Resis

tivity

(Ωm

)

(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

RMSE 21 NA 25 NA

VES

5

VES

7

BH BH

7184

18449

2058

7503

Sandytopsoil

Fine

sand

Gra

velly

sand

Silts

tone

Fine

sand

13622

14408

526

668

Loamytopsoil

(b)


ISRN Geophysics 5

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 12

VES 10


(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

90

100

110

NA not applicable


VES

12

26

12410

1182

6112

48930

26

2107

3979

17214

2282

RMSE NA NA

VES

10

BH BH

Silts

tone

Fine

sand

Fine

sand

Silts

tone

Loamytopsoil

Loamytopsoil

(b)



119889was measured




120601 = 100 sdot (119882119908minus119882119889

119881) (3)







6 ISRN Geophysics

Table1Summaryof

locatio


allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

ISRN Geophysics 5

Resis

tivity

(Ωm

)

105

104

103

103

102

102

101

100

101

ObservedCalculated

VES 12

VES 10


(a)

10

20

30

50

60

40

70

80

Pene

trat

ion

dept

h (m

)

90

100

110

NA not applicable


VES

12

26

12410

1182

6112

48930

26

2107

3979

17214

2282

RMSE NA NA

VES

10

BH BH

Silts

tone

Fine

sand

Fine

sand

Silts

tone

Loamytopsoil

Loamytopsoil

(b)



119889was measured




120601 = 100 sdot (119882119908minus119882119889

119881) (3)







6 ISRN Geophysics

Table1Summaryof

locatio


allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

6 ISRN Geophysics

Table1Summaryof

locatio


allay

erprop

ertie

sand

protectiv

estre

ngth

ofthes

tudy

area

VES

number

Latitud

e(degree)

119910(m

)

Long

itude

(degree)

119909(m

)

Bulkresistiv

ityof

layersfro

mtopto

botto

mof

thee

cono

micaquifer(Ωm)

Thickn

esso

flayersfrom

topto

botto

mof

econ

omicaquifer(m)

Depth

toecon

omicaquifer

(m)

Long

itudinal

cond

uctance

119878(Ω

m)

Econ

omic

aquiferfractional

porosity

Protectiv

estr

ength

Curve

type

1205881

1205882

1205883

1205884

ℎ1

ℎ2

ℎ3

12982

176

6604

14886

5492

12487

1336

478

527

009

0305

Weak

KH2

2828

357

4186

19130

3921

mdash17

1123

mdash114

0006

0350

Weak

K3

2836

607

1304

57202

20494

mdash12

15512

674

005

0278

Weak

H4

2882

794

9499

27155

1464

537452

05

39

161

206

001

0301

Weak

KH5

1850

1009

7184

1844

913622

1440

805

16389

829

003

0280

Weak

KH6

1423

210

14330

2100

8605

83673

194

431

496

1124

028

0260

Mod

erate

HA

71950

1328

2058

7503

526

668

29

118

682

829

133

0195

Goo

dKH

81363

1586

18268

1075

401

647

36

246

452

734

136

0312

Goo

dAH

9581

104

34555

18256

3939

20304

06

20

892

918

023

0276

Goo

dQH

109562

150

2107

3979

17214

2282

07

128

552

687

007

0256

Weak

AK

119740

209

13351

33725

9242

16816

44

556

509

1109

007

0289

Weak

KH12

1867

356

17214

1182

6112

48930

916

567

368

1151

059

040

6Mod

erate

HA

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

ISRN Geophysics 7




0

10

20

30

40

Curv

e fre

quen

cy (

)


417

833 833

167

833 833 833


9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Long

itudi

nal c

ondu

ctan

ce (m

Ωminus1)

1000 1500500




119878 =

119899

sum

119894=1

ℎ119894

120588119894

=ℎ1

1205881

+ℎ2

1205882

+ℎ3

1205883


120588119899

(4)

where ℎ119894and 120588




8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

8 ISRN Geophysics

9000

8000

7000

6000

5000

4000

3000

2000

1000

Nor

th o

f ref

eren

ce co

ordi

nate

(m)

125

1

075

05

025

0


Thic

knes

s of l

ayer

(m)

(a)

1000

500

1500

200030

00400050

00600070

00800090

00

110

90

70

50

30


coordinates (m)

Thick

ness

Thickness (m)100

50

(m)

(b)


1000

500

1500

2000

3000

400050

00600070

00800090

00

100

80

60

40

2030

50

90


of refer

ence

coordinate

s (m)

Dep

th (m

)


50



Δ119881

119881=Δ119897

119897+Δ119908

119908+Δℎ

ℎ+Δ120601

120601 (5)


9000

8000

7000

6000

5000

4000

3000

2000

1000Nor

th o

f ref

eren

ce co

ordi

nate

(m)

038

041

032

026

029

035

023


Frac

tiona

l por

osity

02



Δ119881

119881= 0 + 0 + 01 + 001 = 011 (6)

Δ119881 = 119881 sdot 011 = 168480558 sdot 011 = 18532861m3 (7)


5 Conclusion


ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

ISRN Geophysics 9




References




























10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

10 ISRN Geophysics



















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in










Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

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