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II EVALUATlON OF THE HYOROGEOLOGICAL 
RELATIONSIllP BETWEEN MONITORING 
AND PRODUCTION BORElIOLE..'i IN THE 
UPPER WEST REGION. GHANA 
BY 
IIISMARK V NORGIlE 
1\. ... ' , 111 1,..., •. 1 "'UI. ... 11\ III (i UAN" 
e 
A THF..51S PRF,sENTED TO THE DE!'ARTMENT OF (;EOLOGY. ;1 
UNIVERSITY OF GHANA IN I'ARTL\L FULFILMENT Ot" nm I 
REQ"IREMENTS FOR 'OIE AWARD O~· AN M.I'IUl. DEGREE IN I 
(;EOLOGY 
, 1 
I 
II 
I 
I IIJ'l\KfMENJ l H- (a'.OLOGY 
I 'SIVl·A<\rrY OJ ' <;IIANA 
II <d IN, A.n .' I..'1. 
I 
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DECLARATION 
" pan rrom Ihe numerllus publications and te~1books consulted. :.md for which tbe authors 
ha"t bttn dul) aclrnm,· ~dged. this thesis Is the original work undertaken by me under 
~up{"rvision In the Upper West Region as a project work for the award of a .\'faster of 
Philo,oph) (M. I·hill deg~ in Geology at tbe Uoh'ersity of Ghana. Ugon. It ha., never 
b«n p~nled fOf" .. n) degree "ork in any Uni"'·n.il~· , 
BISMARK NORGBE 
(STUDENT) 
MR. BRUCE KOFI BANOENG-YAKUBO 
(PRINCIPAL SUPERVISOR) 
MR. YAKUBU IDDIRISU (HEAD OF DEPARTMENT) 
(CO-SUPERVISOR) 
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fo evaluate the hydrogeological relationship bt.'t"ct'll monitoring and 
production borehoks in the Upper West region of Ghana. a total of 192 
boreholes were studied. Out of these. 23 are monitoring boreholes and 169 
.an: production boreholes. The types of aquifers being tapped by tbese 
boreholes han aL'iO been identified to detennine Ihe adequacy of tbe existing 
network oflbemonitodrq:: boreholes. 
1be region is undedain by bacoement complex rocks. The rocks are 
composed of granites, granodiorites and granite-gneisses. Metamorpbosed 
volcanics. schists and phyllites of the BirbDlln fonnation occur along the 
western pOl1ion of the study area. 
Three aquifer type.1> were identified from geologic logs and driUers logs 
in tht' l 'pper Wb1 region. These are the weathered rock aquifers. tM 
fractured unweathered rock aquifers and the fractured Quartz "ein aquifers. 
T~ aqul.fers are inter-related and where thcy ne:cur in combination with 
thick o,'('rhurden, yields are enhanced in such borehotC"t. 
Srati<;1ical analysb; 5uch as correlation and regression analyses we.'rc used 
to determine the relatiOll.~hip between the borehole properties, while the Theis 
(1935) Rt'Covcl1 and Cooper.Jacob (1946) mt,thods were u~cd to c'"aluate the 
aquifucharactcristic:s. 
There i .. a signinc:anl rt'lation. . hip between overburden thickness and 
}~Id.<. in the ... Lud) area. About oinet)· percenl of the borehole.. ...t udit>d h,lI\e 
1I\f'rburden thicknesses c~ccedin2 IS m wilh ~;elds of nO( les~ than 10 I/min. 
Generall}". yic-lds r.lIIge b(·t~~n 4.5 IImin. and 270 I/min in Ihe 192 
bort'hok~. The mean and ~.and.ard de\'ialion are 25.4 I/min and 20.3 IImin 
respKtinly. Close. values oflhe mean and standard devialion oflhe borehole 
~ iddl> indicate t~ hderogent>ou~ nature of aquifers In the area. 
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An average dcclilW of 4.1 m in static water If:yels was ol"er\'e1i in the 
~ion. This was attributed to reduced recharge:. 10" rainfall. high rates of 
eyapocranspiration, increased surface run-orr and excessive withdrawal of 
~attr from the boreho~. 
Transmissivity values computed u:.iug (he Coopcr-Jacob(l946) method 
ran~es from 1.2 ml/day to log.2 m I /day in 47 boreholes. The IUean and 
standard deviation values are 35.2 ml/day and 30.1 ml/day resp«t:ively. The 
cI(N.'ness of these value:!>. again explains the wide variations and extremity in 
transmi...  sivity values of baement rock aquirers In tbe l'pper-West region. 
The Theis(193S) Recovery method was used to compute the transmissivity 
valutS of si" borebo&es. The values range from 19.5 to 213.4 ml/day, while 
those calculat£"d usiag the Cooper-Jacob (l'J46) solution technique from the 
same borehole<> ra~e bet~een 24.5 auri 183.4 ml/day. 
h wa... . noted that more accurate tr3IbOlissivity vaJues were obtained 
rrom the 11lei5 (1935) Recovery mcthod than obtainrd rrom the Couper-Jacob 
(1946) method. 
Step-drawdown results used to calculate the borehole efficiencies of five 
bortholes after one hour of pumpin~ indicate that none of the boreholes 
analysed have intffi,:il'm:i~ ext'ttdin~ 75':\ in the ~1udy aru. 
Finally , the «udies indicate that (here exi'its virtu:.tIly liule or no 
hydrugeological relation"hip between Ililll'l, perccnt of the monilorin!; 
boreholes and tM production borehole.. . ; hellC~ che 23 monitorinl/: borehol~ 
e'!\o1ablished across the rqiou a~ not adequately monitoring Ih(' grollndw;.lter 
tents of Ih(' area. They are also not reprc. . entati,'e or the production 
hon'holt"lo in the study arn. 
iii 
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DEDICATION 
To fm Omnipotent, NeflJ13 and St('JJ~ , I Dedicate Thi~ Work. 
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ACKNOWLEDGEMENT 
My special gratitude J::0e5 to !'vIr. B:lnlXng-Yakubo Bruce Kofi, my 
supervisor who painstakingly guided me in the course of my ~-cudies. made 
constructh'e criticism.~ and offered valuable !iuggtstioIL~ in fht' prepuarion or 
this thC"ou. IIi..  assistance and encOllragl'llICnl has contributed greatl~ to the 
.. ucc~. . rulcoDtpldiODoftbisthesis. 
I am very grateful to Mr. Yakubu Iddiri...  u. hl'ad of the Geology 
Department for hi<. remarkable ill.!lpiralion. My since", thanks also go to all 
the lecturers of the Geology Department for tlu.'ir invaluable contribution!> 
durulltbec:ourseofmY""1udies. 
I acknowledge with much Ihank.. . the sponsorship prm·jded by the l,;pper 
Regiol1.." Conununity Water Project (COW API \\ a. to enable me undertllke 
the rese:lreh. Thanks 011"0 go to Mr. Wia:bert Doguli, the Regional 
Coordinator of COWAP, \Va and Mr, Chris Naabayire a member of tm 
District W2ter Dnd Sani,aliun (t'am in Ih{' Nadowli district "ho "("I"C of great 
help in the acquisition of data in the field. lalll also grateful to ~r Raphael 
Nampou. . ou " 'ho lIIade numerou.. . \uggl~linlis during (he lield work. 
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Mis.'i Stella ACua B03tcng oC Unive~ity of Gh~na. Legon, will fo~"er 
be remembered Cor her cooperation, moral "uppon and encoura2ement 
durirlltbepreparationofthisthesi'i. 
My sincere thanks :dso go to my part'nts for their J:rcat love and 
concern during the period of my studies and also for teaching me the value-
of hard work. 
To Miss Victoria Harfoe, I say thanks for ber patience and diligence in 
the typinJ: orthio.tfk~lt;. FinaUy, to aU those who have helped ;and contributed 
meaningrull." in diverse " .. y~ towards the successful complction ofthls thesis, 
I .:rafefully 3cknowll'd.:e and mny God bles!o fh('m all. 
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PAGE 
DreJaration 
A_lid 
l)tdic:uion 
AcknowJedgtlM:Dt 
Tabk orContent5 .11 
Listo(fiJ,:ures 
List ofT.hles 
!.·I.IA~~ 
L'ITRODUCTION 
Background 
1.2 Ifktory of Watrr Development 
I..' Literature Re"iew 
Objectives of Study 
·\1e1hlldf)lo~ 
1.5.1 Pat a Collection 
I.S.2 Data An .. lyshand Interpretatioll 
Sou~ofData 
10 
(;IIA n'FJL1:>Y--'J 
I'IIYSICAL SETn"G OF THE STUDY AREA 
12 
Location :md Anal E"tent 
12 
12 
1.J Climatt' 
F.vapo.rall\piration 
Snil.sand VeJ!:t1atinn 
Surface Water Resouras and Draill:l~t' 
IS 
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Population and Settlemeut 19 
2.8 People and Occupation 20 
2.9 Natural R~ourcl."i 21 
aw::munR-Ef. 
GEOLOGICAL SUTI:-IG A:W HYDROGEOLOGY 23 
General GeoloK,y 23 
3.1.J 'The Blrimian System 25 
3.1.2 Gnrucesand Basic Intrusives 26 
3.2 StructuralGeoiogy 27 
3.3 HydrogeologicalConditions 30 
3.3.1 Mode of Groundwater Occurrence 30 
3.3.2 Characteristics of the Aqulfel'S 34 
3.3.3 Groundwater Recharge 36 
3.3.4 Groundwater Flow Sys:tt'm 39 
!.:IIAm:J!m1J~ 
MiALYSIS OF DATA 
Available Data 
4.2 I.imiratiull.!o ofA\ailahle Data 42 
4.3 Methods of VOlta AnalysLIi 
43 
4.3.1 Cooper-Jacob Method or Solution 
4.3.2 Tht'i., RNO\t'ry Method 
49 
4.3.3 SpcciricCapacity 
4.3.4 Stt'p Drau'down Pumping Test Yiethodo; 53 
4.3.5 Jacob's Graphical ~trthod 
Analyse.. . J'erformt'd in tlw P~'lIr Stud~ 
4.4. 1 Pumpin~ T~~t Anal)~is 
4.4.2 Stati.scical Analysis 
58 
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PRES.:~TATIO:-l ,,-"Il U1SCLSSJON OF RESLI.TS 61 
Borehole Depths 
5.2 Overburden Thiclmessess 65 
5.3 Aqulfrr Thkknesses 70 
Aquifer Depths 73 
5.5 Borehole Yields 77 
5.6 Static Walrr Levels 
5.7 Itelation Befuttn BOll!ho~ Properties 103 
5.8 Aquifer Properties 111 
S.S.. Discussion of Constant-Discharge Test f{~ults III 
5.8.2 Specific Capacities 115 
5.8.3 Dbicussion of Step-Drawdown Results 118 
5.9 Aquirer Types in Observation and Production Boreholes 119 
5.10 ni.~u."ion of the Hydrogeological Represtntativenes~ of MOllitoring 
Horehol~ 129 
m .M'IfA.SlX 
COr<CI..USIOM AND RECOMMENDATIONS 141 
6.1 Conclusions 141 
Rttommendationo; 
RHEREN("LS 
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l'Alili 
A lIIap of Ghana showing local ion of the tbe Study Area 13 
2. tipper West Region· Vegetation Zones " 
3. Geological map of Upper W~1 Region 24 
4. rUIW~wdo'Wn CUl"l'f for constant-dischlU"ge Its. ... 
~ho",in~ Cooper-Jacob's I1l('thod 
Schematic Time drawdown cune/residual 
drawdo'WncunesinaweU. 
Detenninatioo of Band C using Jacob's 
method ~S 
Hist~ram of Borehole Oeplh.~ 61 
Histogram of OH'rbu~n Thicknesst.'S 66 
Histogram of Aquifer l'hic:knb.~ 71 
to. HistOlrAm of Aquifer Oep'h~ 7S 
ftI~ogram of Borebole Yi~lds 79 
12. Histogram of Stalic Water L~vels 86 
13. Watn Lev~1 Hydrograpb for borehole number 398C-OI (KaJea) 9~ 
\'\'aft'r Lcy~ Hydrograph for obsenation borehole nurnher 401A-07 (Jang) 
\\oater Level Hydrogrttph for horehole number 401(;-06 (Wa South 
_~ n 
Water un:1 Hydrograph for borehole number 4001J..()4 (lziiri) 98 
Water Level Hydrograph for borehole l1umher 4031>-01 Wian). 99 
Rainfall and Temperature di(Ocribution in the Uppt"r West Rrgion. 10) 
Waler LcY~1 hydro~r .. pll of observation ~h .. l~ 102 
10. Plot of S..,IQ versus Q for bo~hole number .~q81·1S. 120 
11. Up~ West Re~ion: l.O(";ltion of olN'n:&tiun borehole<i and WIIW IJI 
prodUC1ionho~htlb,,"rroondjnJ!thnl1. 
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I~~!-J~~ 
Loc...Uion ;,lIul Catchment Areas of some Str1!ams 
in ttwregilJll. 
Projtdtd population at Fh"e~YearJ~' Intervals 
in the region 211 
Swnma.., of Borehole Cbaracteristics 
4. Summa~' of Borebole Depths According to Geology 63 
Summary of Borehole Depth..  According to Topography 64 
Summary of Overburden Thickne.u According to Geololt}' 
Summary of Overburden Tbkkness Aocording to Topography 
: I 
8. Summary of Aquifer Thickness AccordiDg to Geology 
72 I 
9. Summary of Aquifer Thicknes.-" According to Topography 
10 Summary of Aquifer Depths According to Geology 76 
SUliunary of Aquiru lkpths According to Topography 78 
12 Summary of 8orehole Y~ld'i According to ~Io,-" 
13 Summary of Borebole Yields According to Topography 84 
14 Summary of Static Wafer Levels According to Geology 
Summary of Static Wllter unls According 10 Topography 88 
16. Stalk Water Levels Recorded during Study 
Ke.ull!o or PtanoR's Correlation Coefficient 
in Borehole Properties, 104 
Multiple: R~ression rC'iults for Yield" in the 
bor('hlllf'O; <wudted. 
R~ro..,iou Aflaly.'iis for Btlrl'ho~ in Granites 
20. Kl":;: r("l!>,ioll Analysis (or Borehules in GrttnsIOIl\" 
21 . ftt·~re<i.. . iuu Analysts for Boreholes in Phyllih:~. 
22. Rq;~joll AnallSL'i (or Boreho~ in Schists. 
Summ.:ll~ of Aquift'r Charactrristics 
113 
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Calculated Drawdown for Step-Drawdown Pumping 
Test at Wa (8o('ebolt':'Iiumbe(' 398I-ISl using results from 
plot of tigure 20. III 
2S Summary of Formation and weU loss components or Tot:.1 
Drawdown U!oing Jacob's (947) method I2l 
26. Numbers and Percentages of Degrees of 
Weathering in the Lithologie.. . of '1onitoring Boreholes. 125 
27. !"umbers and percentages of Aquifer Types 
in ttar Monitoring Boreholes, Vpper West Rex1on. 126 
28. Numbers ilnd Percentages of Aquifer T~J>l'" 
in Iht' Production Boreboles, l'pper-West Region. 127 
29. Sumben and Percentqes of Degrees of 
\Veatherin~ in tbe Lithologies of Production BOn!holes. 128 
3U. Sunutlary of Borebole and Aquifer Characteristico;. 147 
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lli1J!illl.lllJIU"I 
I I BACKGROUNO 
GrtlumlwiHcr !<.Crvc\ as jut cnJint: 01 wwwfh in many .. te;," of Ihe world where 
surf:ICC willer resources are inadc~uiHe or unrelLahle . While income!! and prcllJUCllvlly 
h.we 11~11. III ~\11l1ct:a:.c!l wale I 1:,hleshaYe fallen 
t'vns..:lUus m;u ... !!cmcut III !he: rcwuu,;c is Ihcrefore nct,;c~~ry (1.1 furestall 
:ki\'ersc crft."t:I.\ vn tin: t.'Ullttll1lY iukllhc cnVInJllmcnl including land suh!OidclM."C. 
JcplclKlO CI' the le ...t lUI!,;C and tk.-Ieriuralion of Iht waler quality 
In ;UI alicllIpl III IIlIproVe the 4u;tlity of life of Ihe ~oplc and allO to combal 
I~ inckkn..:.: uf walcl-home and waler-related diseases III tI~ Upper Wesl and Upper 
East rqioru. [he: Ghana Wiler and Sewerage Corporation (GW5C) in collaboralion 
wilh lhe COIn;Wian IOIcrn.1Ihu131 Develupment Agency (CIDA) have frulII 1973 to dale 
Jrilll..'d 2,(1110 l)IIrchuks tn cxpand ,I~ wale, supplies for the t\lo'O regions Pnor to this 
prllll.'-I , nlh~'r dnlhnl! ;K"llvilics by some agencies had taken place in these rcglun,,, 
AUIUII}! the 2,600 burehulc5 drilled, l.01l\ are located in Ihe llpper West 
fl,'):,IIII In ;uidilion tn Ihe~, Ihe C.uhulil.; [)iut:c~ uf Wa also !lponsmcd Ihe dnllmg 
llf a f'unhcr 350 well,. 10 augment Ihe supplies 01 waler in the region 
A network or !-4 observation wells was cSlahlished across the tWit regions 
AmoJ1i chc::sc. 2) of the uh~,....~ti()n borehoLes arc round in Ihc Uppcr-West region 
and~lohe",uniluri"'the~ruullllw"lcrresourt:esuflherett:iunllo~ycr. 
it i" dlluhtrul whether che dOlI" (mill chc~ ,-tl!'oCrvaliuu wells ackquOIh:ly ICPll''C1I1 the 
hydrut:roto,:icalsltuallonintht Uppc:r-Westrrglun 
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C"nsMJering Ihe wKJe .. h~lrjhulwn (If boreholes and rhe heterogcneous nalure 
tI/ .14U11cn.: III Ihe n:'GIUIl, It IS necessary Ih.t appropriate measures are taken (0 
IIWJIlIIor Ihe I'lcha\lourot aquifers in this pet:uliar situation 
As a resull, this rcscan:h under1akcn for the Upper Re,.iun~ Cummunity 
Waler I'wjCCt (COW.I\P) W,IS I,;I'ml\.k:l~'u ulklcr the Action Rescarch Fund anl..Ithl: 
N,I{IUI)dt SU;ltcgM: Inv('slIne"" Pnl~r;1I11Ine (SIP) to stuuy the 23 uh!iCrvat ion boreholes 
In "ruer III .. ~s.:~, wllI..'lltl'( Ihey ;In: 1I: .. lIy rcprc'-Ciltative of the pn)(.lucuon borellt,le)' 
;auotu Klclllify the type ol aquifl:rslhcsc wells are tapping 
t.2 IIISTORY OF WATf:R DF.VI':U)p!\fENT 
lItlore groundwater became a major source of water supply in the study area 
forhothurblnafl(l rur:tlptlpulillions. hand-t1ugwclls,dug'OUls.llIlcrmlllenlslreilms, 
I,UII WOller I"Mrvc!>l1ng alkl pUlkls ~rvetl a~ Ihe main water sources for the ruml 
!.lweI/cr!'. Iluwc::vcr . pllI'r lu the l'.l13 projel:t in Ihe Upper West n:'!!ion. a (ew drille\! 
hon.:huk,:sexlste.J in the IOWfU 
Mus( of the Willer <;tJUKes 00 nul last the dry ~easoo duc 10 excessive 
eVOl(lUI.Ulun ~sultin@. (Will high (cmperatures and low humidity . Ifeoce, lhe pcuplc 
"'=rcf-.J un the temporary dug-iJUlS alons: slream beds for waler , These !iUurces are 
InvanahlyheavilYClllllallllJ1,;JleJalklarecauscsofthespreadofwater-borncdiseases 
such OIS Cholera. f!ulIX'a ~ornl .11-.J hllharzia amons: Ihc people 
Cllnscquclllly. IIX' U!>C or groundwater has he1:01l)C nect~ry sincc 1973 when 
lhe Gluna WalC'r and Sewc~,c Corporation antJ tl)C Canadian Incem;lIiun,,11 
J)eveklpmcnc Ageocy helped III curb Ihc problems of waterlhorta,cs in Ihc regk.ln 
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1\1 ... ,. III 'l.*Ccnl ~l'.II-S, the Calhuhc l)iocese .. f Wa. Water AnJ. Valll!>h 
InlCrllallonal Development A!!t!IJ.:Y (DANJDA> and OIher nvn-govefJunenlal 
OrJaniSlIKHlS have provided clean po.able ~'atcr to most of the rural populatinn.:" for 
doll~ticu~ 
nil' ruml ~Of11lIlUIl1l1C!i ate ),upplied with WOller frum well!' filial with hand 
pumpl' wl~rl';15 urhan (tUlLntUIlIltC\ wl,1t \l.:11<lOls, 11I'~pll.1 1s and IOWII~ oblain wa(l'r 
11"111 \H:lhlltt\'d Wllhfuc:1 [lUmps 
I he Upper He!!I ....) , Cmnll1l1l11ly Watcr I'ru)l-C:I is Ihereftllc invulvoo inc.:lc:llill)! 
new wtllcr M)Un;es for Ihe peof.Ile and e:tamining the hydrogeological aspects (If pump 
replacement as well as land use and environmental impact on water resources 10 
funhcr ..sevelop the groundwater resource base aflh( region. 
Crystalline h"\oCmel'll (ernUL' 111 UOPIC3' 311(.1 sub-lroplcal ICt!IIIIIS .m: IKlW III 
Ihc Pfl.w.;C. ..~  of vcry eXlcn>;lve dt-vdopmcill as a readily avail3ble allern,'II\-c -"ourec uf 
WlIlcrsupply furlOOst I1.Iral pnpuiallulis 
GUslar!lOn aflll Kra~n)' (1994) discus~d lilal the importa",c uf hard rock 
;,quirc-rs ror hydrogeol~ical and waler management issues differs rmm place (0 place 
"1llI dcpendt mainly upon Ihe uverall availability or water and water demand , This is 
,,;vlJenl in many counlries where surface waler is unreliable 3S a major source or 
t -lull,," ,,'II.J Snlllh·c,;ulII}!IOO. IY~ incJic"lt: thai the pre'-CII(C' ur ;t rdal.\,cI) Ih~" 
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Lbllucn,-Ylkubo (1989) noted Ihal the occurrence •• f ,rouoowater in 
I.:ry~;IIIH1c h.l ~'; IIM:UI rll(h of 11M: LIpper RC: j! I£lm depends In ;t large c:\tcnl 1m file 
rlud.IIe" " I -.IIUfilll'\l le~ohlh ... 1lI the ;lI.julkl Jcplh. lie further floted thill 
W'It-:hlct;l! (198S) repolleJ lh;lllu!!h suslilllk"\l YIelds are tu he cxpected 
\\otM:ccboreholespenctratcasi,nilkantthidnessofsaturatedpcrrucableoverburden 
;100 10111 lraclureO bc.'tJruck wilh both sections screened . They also observed Ihal 
rr:k:lurro bahnd lend!" have hilh lransmissivity bullo\\' !Olorluivity contrasting with 
lhe dayey ovt'roorden uf luw 10 moderate transmissIvity bUI high storalivi'y . The!.!! 
.1'lUlle, ch.,.,acleristic.s depend mainly on the extent of rracturing aoo weathering 
' ''-I.urflng mlhe nICk" 
Huwcvcr . ,ulullel ~ 111 the u Y!.lalime b"",,'lI1cnt 01 the Upper Regiull" .Llt!' 
dlilra.;le n sC\l b)' I(ow tr.UI!imls."lvlttCS atlll rc:pCIIlcd to have variabk hydraulu;: 
cl~ra..:tenSl.ic.s uvt:t short dlstancc~ CIlJAlOWSC (1980) 
The: avcn):c yield to be obtained fWIII a ~roup of wells C3n be c:slmlalcd 
when: sufrlCienr. dilta on elmtm, wells ate avaIlable . Heath (1976) reporlel.llhat since 
the yiekJ of a Itlutllldwatcr system depends nn the areal Cluent of the aquifers 
c"Ulpmm~ the $~stelll aoo the hydrolQl!ic na.lure tlf their boundaric!i. the 1I11J101 
1""d'LoIl ..... n to determine tht: t:\lclllllrsueh aqulrt'rs IS III uhscrve Ihe regional 
LOllhnUllY III ".1I1'· Inels or I" Lllllect data at wM1ely ·srat:eLl (Ih!iervaliun well.. to 
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unlUoowalcr as.sc»ment in the crystalline terrams of Gh.1na cunducted by 
Gills (I%~, c,tinlatetl INt aboul mnety percent of borehole!' drillC1.l in crystalline 
~!<menc rocks up 10 I depth IIf ahout 34 m (110ft) will have yields adequate for 
h.llkl pump IIlS'aliatlulI if the horehoLes penetrate the entire lOne uf partially 
JC~"fIIf1'J)(\1 flJck down to the level of relatively fresh t\Xk 
l :ea~lbIIIlY )IU\lICS to investigate Ihe C\I)lll1g walc:r suppllcS uf Wa Ullhe Upper 
WI,:sl reginA indK:llled thai the causes of the drop III water levels was \Iuc 10 the 
IIHui .. of lhe groundWOIh:1 Ic\Crvcs where ablOlraclion e .\\:ccd~ rceho.rgc, and the life 
I)f the bun:hok is const.'tfuclltly Ii kely to be limited (Humphrcy and Sons, J9 70). They 
furlherdiSCUi.o;ed Ihilihe period over which thiS abSiraclion rate could he suslained 
is,. funcl,un of the trnllSl1Ilssibilily.lhe storage coefficient. the depth orille aquifer 
.100 the amount 01 natural rcchar~c 
In the rltliIl hy\lm~eolo)!K"al n:porl lor Ihe dniling progralllme in the Upper 
Re~u;ns. CIIJA/GWSC 119~1. II .... as stataJ that ill choosing observalillll wells in the 
rq~IIIU!o, ('IanK:ul;;u c(lflSldc'dllUlI wa~ ~H\;Cn 10 wells with high yicldl'i and lu .... 
dnw\luwn. '11M.: ~tatlC waler Icvels in thesc wells were only taken after Ihe wells 
rt.'I;uvcm;i aJCcr ('Iumpmg. pruvidcd (he dfect of pumpin~ mmlC'dialely prior to 
"hl.l1nin, the ~lallC walcrlcvcl wa.o;mininlllc4..I 
rt.: .ll1l11unt uf water avail.ble III rCl:h;lr~c In basement ohlulfers depends 
mallity lin .he annual tocal rainfall. However. Uanncrman and Ayibotc:le (1984), .nd 
!'al,yet al (l987)ntimatedanaveragc rcchargebelWttntwoal'ld three percent or 
II~ itll,...' ralDralllnthe UpprrrcglOrtstl' Gh;H\;t 
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TIle' need fOr the cunlllluuus monilunn~ tI' gn1ul)ljw:llcr systems Ihrnultholu 
Ghal);1 !'OI) a.o; II) ~cnerall" cJala ror management and plalUlln~ purp()~1 can be Khieved 
Ihruu~hlknsllydclernlln.llllmu5U1ginform.1Iionongeologyandclllllalcassuucsled 
by Ihe Water Kesuurc.:t:~ Rt'~a".:h Im.lllute (1990) . 
UNEP/WIIO (19871 prupu!.C1J Ihat the mOIllIOril1~ S)'SICIII of wclls need 10 be 
'Irclll!lhtrk.-d . ()h~r"'''lItlnwcllsmU5IbcrcprCM!nlall\·candlhcvariahlesmuslhave 
lhe sonne valuc), as lhe pro,Jucllull ".,-ells. Fur1hcrlllclrc. OIc.:ccs."ilJilily I' ,11111111"11.111:11" 
cOfukkraholl lor the IIIOUllunll)! crew. pal"Ucu larly In reglollS cxpo~ to severe: 
dUllaliceundilions 
In order In establish rel!lunal trends wilh which to manage aquifers in the 
ery"~lIine rocks uf Ihe Upper IC!!U)OS. Bannerman and Ayibotde (l984) suggested 
thai Lhac: It) the heterogeneous and localized nature of these aquifers. the most efficient 
wly IlIlIl\InilorprodLl(lionbo~holcsistousclheprocJUI,;IIOllh()feholeslhelllselv". 
inINltlillJumlll'rllfhou.:hu!t::\ inlhcart'a ISsc!ttlcJarlLltakcn:ls;J.S3U1Il1cnt"many 
Ih\' ~ .• I~., ,UI!\·J rh •• r rill· ..... h •• \ hcclillU sll!lIIficanl da:linc of w:tler levels in 
11Ie.· I. ... u rq!'''iI' .ncr ;r hOot'llly-year period since Ihe 3\'eragc water Ic\'(~1 \,.h;Ul!!C over 
chi' period I~ cOll,iJcrahly ~lIIalier Ihan the se .. ~unal nuctuauon of water 1cwh 
I>:Ullcl 119')(JI repuns thoilihe only way lei ensure Ihe mosI. emcitlll ureralrun 
,,' .1 \'e.'11 IS to clusely mOnilur wmcr levels and pumpin~ ralc ... . Wllcr levels in Iht' 
I" UJlk "'4U1II:1 perrulI"a"cl" Knuwlcf.lge ur tillS is vilal ror 8n oplunurn utiliution 
.)frhc aruundwaltr resource.o; 
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Sialiman (1971) also discussetllhat the accurale local ion of oMcnation wells 
Wllh referenct: 10 the posllmn III prodUl,:llon wells is especially impor1ant in a 
htteru"c:nctKIS tlr J.nlMJlruptC ;!4Ulfcr . This IS netes.sary !>O thai lhe data obtained can 
be ctlecllvdy u~ 10 p'Jrlray the ~uifer L:hara~lcrjslics 
Act.:onling 10 Akiwumi (1994) the significance of a groundwater moni(orin~ 
ncl .... urk In any CtMJntrycalillOl he lell unmentioned. In many develupingcounlries. 
the l.lIst of ~fablishill~ IhlS nclw(llk i .. expensive due to limiled rcsoun:es. The lack 
hCIIl'etbUlisurlCIlUllrcilahlc 
Gruundwalcr ICSUU'I.:c,'\ Ik'cd 10 lx' 1,lIh)J ... IJ~ managed In prevellt lhe 
deterioratiun Ilf Jroondwatcr '11101/11)' and the !>Ide dfccl" Oil Ihe environment Xlao 
(1."..,4) dl~usscd Ihal 01 primary }!roundwaler IIlUnilorin[l Ik'l\Hnk ,h"uld he 
",,-,!ll' 'u 11",1 IlIh'IIII.I,iUIi CllllcdcJ tWill this nelVol,rk lIIay prOVide Ihe.' h .. sis (or 
)!r(lUllIJwatcr rcsoun:eplaruunf!, IlIdlaagelllclll ant.! hydrugcol'lgu,:a[ )tu,",ics 
Groundwater SIOOlcs cnndut:led by Malian (1959) in the Uppcr regiuns of 
Ghana show Ihal there IS a Ji!cncral tow nitrale concentratiun in the region with OJ 
mean \':.Iucuf 1,5m!!'''IIC Onl} ,'rte ~lI1ple with nitrateconcenlralion higher lhan 
tJ 1II11/lilres. btu lower than IU IUgllilres was encountered. PeliS.Ba el .1 (1985) 
R.'Cnrdec.l mtralC levels as hi,h as 127 mg/hlll:' in 'ume horehulc!> in Ihe Upper WeSi 
'cF'Hn I'hc!iC '''>Iilted high values may probably he Ihl:' rc~uh nr local pollution 
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'n.: prIIl).!r) objective of this study i~ 10 evaluate the hyl.1rogeological 
reL1llunshlp bctwL'Cn lIIonuurlng htKl:holes aoo production boreholes in the Upper 
Other ubja:uvcs incluul' the rtlllowjn~ 
To KJcllliry the Iypc~ of aquifers thai the monitoring and productioll htlrehoks 
om: Ulppinl! In the ,c~lOn;t11Ll 
hl JJucd un the IlIldllll!~ 01 thc pnl1JaJ)" OhjL'Cli\'c, ,I ~cnc ... 1 review uf the 
mOUlI()rin~ "ells network structures would be put in place 
'rhe study would therefor!! nmtribult 10 lOe understanl..llng of the groundwater 
potential anduccurrenct: in the rei!iunas well3scSlabiish h)drot:colo{!tcalcOIklitiolls 
frqUlmJ fiN" the location or lIIonitoring wells in crystalline bascment lelraills, and 
hl:llu: prc<;efll:.. .,Ialus 1m Ihe luture tf'elwJ!. 111 all .. ~pel.:ls of,rolJOdwaler J'cStlurCe5, 
UIIJI/.aUIIII and t1C\'c!Ut'IIIl'111 
II .. 1Il~'lhtldllhl~~ "d"j11L'tl IU achievc Ihe purpost: of Ihis ~IU"")" cOlnpnscd 
11U1ll1ly O.laCuIlL"Clioll. VOII" AUOIlysisand Interpretation, 
Il.ll.U:Ql.l.hlI!ll!'! 
I} The rev;cw aflll study of exisling literature on grnu.k.lw:IIler in crystalline 
hiotxmcnl ruc;ks, 1I1l' ~ona;'JOn of borehole lug~ 011 Ihc 23 mlJflllorin~ 
hurchok:.J.nd 161J I.:hu'oCU pruUUC1t1l1l borcholes 
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TIII~ infonlllfMIII ".1\ onl.1iuL-U from the CO\\',\jJ/GWSC Office in the ~tut.ly :lrea 
FiellJ \luJh:!>, induJill~ lilt: me3~urt'II"':lIt ()f Ihe st.ticfdYllallHe waler levels I)' 
IllI: fl)unilOnng anJ sampled pm..lUl.:llon boreholes thai are distributed in all the 
fivC' distnctsllflill'SIOOY area with a well sounder (Water Level Indicator-
SOUNST P2IMJlROM) 
'nle Gluhal PUSllWlUl1g S~ \1 ... 111 (GPS GARMIN 7.5) inslrumC'nt W;IS uSt.'tl tu 
loc;!!c the positiull ,IIlJ dcvation ahove ~a level of Ihe production and 
lnomturin, borehu'. .. s 
d) Retitle the luc:lllOll itOO elev.fion of the 23 mUlIItoring boreholes and 169 
~alllplt."I1 proJut:lum burehules to the geology and hydrogeological t:onditions 
Ua.OII ;lIyl),sis invlllvct.lthr dctailed studies()rtheeJti.stjllg~culugicill repurts. 
h)'t.lrtI~~. . 'oIH8ic31 repulI ... 111;'1''' arM.! borehole tQ~" of the ~Iudy area wilh the 
VICW IP":;I'q!lIri1-illglheoflscr\'atiunand PflJdUCllOn boreholcsfo identify the 
tYP\-'ulaqutfecslhcymollJlur 
From the analysis. the pcrt:enta~e or the observatiun horeholes that lap the 
m.in aquifer types was tJctennineJ. the same was done ror thc sampled 
pnxJuclionboreholes 
An cvJlu;Uiun uf Ihe hytJraulic charactemltCS ur the hun:holes frulll lhe 
From the slI.Jdy uf the 3\'ailabie 100 currcmly me.l~urctJ Malic Wiler level data 
on boreholes, the lrend In sucic Wiler /c\t'I~ tI\er lhe- years was eSl.ahlished 
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rhe e'ilablishecJ resulb 0I11Il pcn:elllagC\ 1IM.lu• . IIl' whether Ihe lIl.un aqui(er 
lypc.!S OIre ;nJclju;lldy IUlImtored b~ Ihe eXISUfI!! r.clwort of ubscrvalion 
horcholcs. 
Similarly, lhe corrdalioll anu regression analyses helped to estahlish whether 
then: exisC~ fill)' !ollnilarity III the borehole plllperllc~ IIIll1e cJ,I'fcrcnt rttl.:k Iypes 
mlhe IC~IIIII IIIC\,)(,:cllve uf thelT spati. . , anll localiuna' dlllcn:llec" 
&J 1I;a-.cu "" Ihe 11I1Il",!!,. IIJ.lI" :lIIcJ ~raph!o ,clatiu!! the \'.1I1I1US ,HlullL'r and 
nClrelu 11t'f'arametel'"CICplc,'paroo 
SOl/HeRS OF DATA 
I"".,enty Ihreenh!>Clvaliun bureholesaoo a s. . mp'eof"l1c hundred and sixty-
!line pnlCfuctiun oorchulcs wert chosen from the main data base of about 1.018 
ho,e-hille, in iilli the distmh uf the Upper,West RCl!:ion (rom the COWAP urrice. 
PlrtlCul.u c,'un,Kk,alllln was ~Ivcn to high-yieh,Hnlt wells. thou~h cJ:II;1 Irom some low-
yielcJm, well!> were IIlllllcJro . In acJcJilion. data from some redeveloped horehules were 
.thlaUlC'd from the Techmuilea01 ;.tIthe COWAP offICe in W. 
0.1. obtained for analysis wert derived from Ihe pre-projcct boreholes drilled 
between 1954.nd 1974 .•n d boreholes cumplele,", by CIDAfGWSC netween 1975 and 
1979 Some or these boreholes are mechanized. where.s others ale fitted wilh hand 
pumps 
l)al:t 101 C\alu.llulII til .lljUllCr propcna of some proouclulIl btlrchulcs in Ihe 
w;\ Nnrth ;11"'-' SlIulh wdl IIdd~ were ot'JIained when pumpin~ test W:lS perfomn by 
Ihe K·illl.\~\ UnlhlIJ tJnlltC:llllnr Ihe Ghana W.ter a'" Sewtrage Curpornllull illlhc: 
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101llnn3olloo on wme IlI.lfeholcs selected ror Ihe 5100y was obtained from c.Lala 
pftlvM1at by lhe Calhulk: DilM.:esc or Wa and lhe \Valer Resources Rcscan:h IIISIIIUIC. 
Acc"' . This infonnallUII indodcd borehole records Ind hydrogeological reports 
nle MI!(eorulu~lt:al ScrVtce5 Department of the Upper West Region lnade data 
dv.ulahk 1111 till' .lIl1lualrainlalllul;lls ill millimelrc~ w\'cring " period of twenty sevell 
ye;.," Olher 1II1uflnaliun obIai,w.-d from Ihe depaltmelll included the lUean mUlll"l), 
lelllpcraIUle~. Ihe mean d .. ily minllllum alld 1II;1)(.llIIlIlIIlclllpel;lIulI:" in dcgn."C's Celsius 
Jlll.l the mnnthly relative humidilyiJata in percenlages 
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CHAI'TFllTWV 
IhcllppcrWcslregiunJ1C'\\ltlul1lallludc ... Q'40'N · ll - OO'Nandllingitudes 
I"'J(J'W . 2"5YW It is tine uf the ten nrJminlstratlve rej:ion.~ of Ghm~ 
The region IS divided into five districts n.uncl)" Wa wludl is the u.:punal 
capillI. NadowJi. Jirapa ·Lllllhussic. Lawra and Tumu dislricb " :,g.urc I) . ll.e legiull 
c.:O"'(Banareao( 18.476 kill"" II is hounded in IhecaSI by the Upper Easl region. and 
10 the south by the Nurlhcrn Re)!iull ft is also bounded hy [he Republic of Burkina 
FL..:o 10 (he north ,litO" ('\1 
2.2 KIiJJ£f 
11M,' ,h"h .111.',1 " dliu'M.:lcrizetJ by D 11011 and gentl) UndUI;1I1I1~ lor"~raphy 
Ihe 1I,:IICI I,IIIIIC' Iroll1 ~J 111 I .. lOU Ill . ~hl\\cvcr. elevatluns <IS hi~h as 400 111 are 
~ujlc ':(1111111011 flaliani..ls ,lie prC\"alclI(' wiulsi low and gCOIlc hills 101111 the main 
n:lief rcalurC'~ . The: uluJulall1l~ terrains have palctlCs of rollin(/: plains scattered 
thmu~huu( (he irca. HIli:. uflen form ridgc~ "!retching ovcr tCIiS of kilomctcrs (ridgy 
IOpogr.tphy) Thc"CrllJi!C\ .. h,)waC"lO<iC: rclalion 10 the geology of the alca strtlChing 
along the :.cuke ul musl wck 1II,I\<oCS 
nle t!cllcr;llly subdued wpngraphy couplet.! with the low r;lInrali has led In the 
olrtil." liuwc\cr . wlltre I;u}.! ... IlIhu~Jle~ of (he Dlack VoIla river l)Ceur. wcll-dclmcLJ 
valleysan:lound . 
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FlO. 1 A MAP OF GHANA SHOWING LOCATION OF THE 
STUDY AREA: UPPER WEST REGION 
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1lle rCJ!IIIO falls within I~ Guine~ Climatic zone and is mainly mlluenced by 
IWll air masses; the North-East Trnk Winds and me SOUU1 -WeSI MOIlS()tIll); . nus 
clunate ISlropK:al in nalurealll.lcharactcrised h)' two main season! - the wet and dry 
The two ;JIf massc~. thai is : the North-easterlies and the Suuth ·westerlies. 
wilich converge at Ihe Inter Trupical 8ouooal'~ (ITU) are cuntrolled by two 
... uhuvptcal hi(:h p'C~MJIC helts tTaoo(lh. 1985). 
The S(lulh-wesl munsoon thai hlows over the re~lon conllins a grc"t deal of 
Wiler '1"pour wluch it cullc:clsdurlllt! ils long journey across thesc:l . hs inlluencc:is 
C:J.~r~nced during the wet seawll. This season is rainy and. starts from April 10 
Sq)lcmbcr The montho; L·r Aprtl. May, June and July have rains of shun duratioN 
WI,h III~h IIllemHICS KOIIII!o .tn.: nllen p~eded by thunderstorms and IIghtmng . TIle 
mean I1Klruhly ralOfalllll May I~ about tiS nun . Ilowever. the peak 'OII11Y period 
Ik:CUf$ from AuglUt W Septelllhcf . where there:1re mUle rainy days than dry JaY5 . 
Mams ;lIcI,:ulllinuuus wilh low IIllensiliesand relall'lelycool days 
Mean Rlo,"hly ralillall as high as 900mm is experienced during the ramy 
perluds in tilt re"on. PohaJash (1965) menlioned in his survey thai rainfall in lhe 
region is in !lie fonn of tropical raiRSlonns Ind about thirty f' '1e 10 forty percent of 
rain is n:corded dunng lhe peak rallly '>Cason and aMual precipitation averages aboul 
1200mm 
rile Nunh ·easllr;u.te willlis blow frum the hc:ut of the S.lh. . r. . ·Arablan dc:sen 
aoo il IS ;US(M.:latN With dry. cool winds known as the Harmaltan. Thi5 period 
n()mtally tlU:urs III the months of December. Jarwary . and February Humkhlics II'( 
low.)nd Ihen= arc nu ~lnsaAIJ llIJ!hldew 
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rllC"'C. ~oupled wllh II pcmlanc:nt inflow of hot. lIry wind from (he Sahara result! in 
hi8hevaporallon and lransplrallon rate5 which eventually have deadly effe clsonsome 
plants m the ~n:a 
ThchanllOlll,1I1 '>Casun in the region l$ciura,(:tcriUti by hiahday tClllflCfalUreS 
and luw lempcratun:s ,II lIi~hl. There is IiUle (:oooensation in the I.!ry ;,tRlo"phcre 
thertby resultmg In ;1 ~eneral ab!>Cm:e of ram doul.!.. However. occasional 
chunderslomtli lilt' cxpcr ..: oclo.'1.I in fhe afternoons tlr eH~lIInl!s Thi~ period normally 
OClurs inthC' munrhsofOctober. February and March 
Temperatures Ire rda!i"e!y high ranging from a maximum daily temperature 
ofahoul40'Celsius in March to a minimum of tS·C in January . n.e monthly mean 
daily lemreralure .. vilry 1111111 10" C in August to )4"(' In M3rch Generally Ihe 
Ivc:rill~e annu;lIIC'lnperalulc 1\ ;llltlut \O"C 
Kelalm: hUnlKh,y III tol:IY III SI:plclllhC"r rc,H:hc5 finy I.' 'oC\OCIII)' percenl (!i(). 
70'10) In lhe weI 5CiII.sunand 1•.I rUpo; 10 about 15% during the rest oJl [he year. The mC"n 
;,"IIU<l1 n:latlvt'hulnldH), r3n~cs (rom thirty seven to forty six percent (37-46';t) 
Evaporallon and 'I,III'I'lIalion conslilute major cOll1pOnCIllS (If the hydrologic 
cycle l1te!oC two proc;es5es, when they oa:ur together is termed !:,·apoIr3ospiration. 
It is Ihe ..:ombined effect or evaporation from tbe surface and groundwaler as well as 
lilt Ir.lnspiration uf plams. whc:n: waler iii lost into the atlllosrhcre. TIlis depends 
larp:dyunlheexr.c,.towhtdlWatcrlsn. . llilbleallhesurface 
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Owing 10 the hij!h temperaturcs .nd heal experu:nced in Ihe Upper West 
re,ion. pOII:naial (v3poeranspiralion is very high. Estim.tes made by UNDP/FAO 
(l%7) indicate Ilul on Ihe basis of rainfall and runorr data. the actual 
evaJ'll'Ir.wnspiralion avera,l.!es around 890 mm and falls 10 635 nun in dry y\!ars 
8alkJC:nJ;-Yakubo (1989) n:pnt(eJ Illaithe rate of evapotranspllauun is accelerated 
thruughthecombinedeffectofvariablerainfall,temperalure. hUlIlidilY and sunshine 
nle lipper We" IC~lon is c;ltt:gOlllcd undcr the Guinea Savannah Woodland 
type 01 \lc~etallon (figure 21 Shon trees occurring singly or in clumps with light. 
1I)('I.lIul1l or denser grlss cowling 11)(' ground between them is prevalenl in the .rea 
PaLChy gf\Jwlh~ of "",kJland wilh moderate grass cover are occasionally 
fuuod . Uillercni 'pt:\:ICS uf trees such as Shea·buller, Baohab and AI:3da Irees are 
very I.OUlIIwn . Strcam dlannels are also dominated by denser lrees and grass cover, 
Whllsl mauhy lands occur III some places. 
The pru-.:ipal soils which cover the study area are the groundw<&ler laterili!; 
~Ulls and .... vannah ochrosols. The lateritic SOlis are present al generally shallow 
depths belo ..... Ihe wil ~urlace and mure or less of a cemenled layer uf lrun pan 
tlu'oui!h which rain WOller ..JUC!i nol easily penelrate The texture is cuarse. sandy-loam 
If developed uYer granrtc~ 
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2-00' I- 30' 
t:-::.::"~. -----.:: --" ~(7 
.~ SAVANNAH 
10-30' 
~,., ZONE /t'" 
i / 
I 
I 
\ 
.-
Ii' --_./ r----
---_/'-_/ 
~ 
~. 
SOllrc:e : Aru, W. L . Waldrop and Anoclof .. (1980). 
FIG.2 UPPER WEST REGION - VEGETATION ZONES 
17 
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l'ht: ~\· .. nnah ochrmuh Ire well·drained, porous, loamy soils i( developed 
over graMes and Birimian rocks. They art! mildly a(;ldic (Dickson and Dcnnch, 
l'IgH) Generoilly Ihesoil i:mw in Ihe area isoor (hick: and the mOlOt rertiJc soils are 
u,u.llI~ (ount.! in the villeys ur riven. streams and at the (00« of hill slopes. 
2.6 SURt'ACt"' WATER RESOllRCES ANn DRAINAGE 
Surface water, mainly dams. streams and the Black Volta river serve a~ 
altcrnatives 10 dle ~ruundwall'r rcsoufCeo; to meet the increasing waler demands of the 
peupk in (he regiun durin!! the miny seasoll_ However, most of the surface waler is 
cpMmeral and dry up III ttle dry season. Only small pools of sl.ncilng water rem;lIn 
TheM: puolsal.J darns are easily cOIII,umnat.ed tlHuu~h agrll.:ultural and other human 
The only pcrculII:!1 rIVer," the region I~ (he Ulack Volt • . It nows roughly 
from the IlUnh 10 the ~outh . Its c:llchmclJl illC.1 is very extenSive and I large 
Pf'O(I()nion or WI'!!r is drained from its triburaries such as the Kamba, Pale and San. 
Tbe Kulpawn ;lind Sis.sili rivct!. drain inlo the While Voila 
nrcpoorly-defined valley noors and depressions llCar lbe villages are 
cOluklcred as streams SUl.:h dcprc$.Sions make II dlfficuh (or any surface 
impuuoomcnI to ~ ulldeflilken ~lIxe (he catchment arca i. too small ant.! discharecs 
rrom (helll .m: fCi:ltl\c\)" lIl.uk~u'lIe (or the ml.rca~lII~ population c5pt:cialty durin, 
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11K overall sud;. ..: c lh.IUL.I!!C \)'Iem in the region is dispcrsctJ bul pauernetJ 
10 a dense and dentJrillc manner. increaSing in density rrom the nonh Inwards (he 
wuth. However. the rectangular drainage pattern is also common and occurs mainly 
al area! .... hcre (he rocks ale Juinted, Streams like the Aruba, Kule, Vetare, Pale, 
Uele, Molcbule and Nowenell:n~ dralO InIO the Bloll:k Voila and practically dominate 
the entire llninaJc network ul Ihe Uppcr West region 
TABl.E I LOCATION AND CXITHME:'IlT AREAS OF SO.\U<: 
smt-:AMS IN THE ItELION (HU\II'HI<EV ANII SONS.19701. 
CATCIIMF.NT AMEA 
(~qu.re kill.lf1lrt"") 
42 . 1 
Bel< 
1817 
b) Kpongu 21l.4 
POPUI AriON AN!) sf:rrt EMENT 
In 1984, the Upper WeSllcglOn had a popuJ:uionof439,161 people lO.an area 
or IK,476 kID squ;a.re aud the ruplll.ation density was 11 pcn;olls per square kilometre , 
HJlIllCnnan (1990) plOjC\.lcu that thc expecteLl growth by the year 20CK) would 
1Ilt,.ICI'(.· by 2.91 % alll.l the IC)pon could I\;I\'C: .. pupulatinn or 690,000 people . Ite 
lurthcr projeCted the populatiun to five yearly intC:lvaiA: in the relion as shown below. 
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TAULE 2: rROJt;Crw I~)/,ULATION AT FIVE YEARLY INTERVALS 
IN THE REGION 
Ali il is charactcrl1oCu.: ul" Nunhem Ghana, about 75 % of che populalion In the 
rqion is 11.11'11. lhou~h uroon Im~r;llIl.m has hct'n un the: int:rcase in recclII years . A 
liule over SO~ of the people ill the Upper West region live in the Wa and Nadowli 
distticlS which COll$IIIOII: dK' JII!!hcsll.Olk:Cnlralion lIf urban population. followed by 
the Lawn. JirilpalLalllbu~lill: lInu Tumu d,stfll:1S re~pectively . A sis,mflCant number 
or people live in towns hke Nalldom. Jirapa, Hamilc. Kaleo. Tangasla and Dodmon. 
This trend of rural·urban ptlpulaliol1 concentfilllOm 1\ nul expected to change much 
by I/)e eOO orche year 2000 
rhc.: ptlpulOlliulI uflilt! area isconcenlraled in small senlclllcnlsusually localed 
at market centres ant! alon, the valleys of rivers. Rural settlements are mostly 
nur;'e-.IllCiJ. The Turnu discrict has the lowesl population demity . This bell is generally 
caUed [he -Tumu gapW mainly due to [he difrlCult physical en\lironrnent whIch 
acCOOIllJ; for Ihe I. . r~e omnl};lhlled slrip of land 
The Ingaaba and Si~.,alas are the main e[hnic groups in the re,ioll '" tul.- the 
WIUas live within 5enlemenl unill in and around WI. the regional I.:apltal , The 
l>agaabJI (ritle ;0; the: domm.lnt tribe and they occupy most or lhe: land are .. mainly in 
lhe N-'owli . Juapall ~lInbuss~ and uwra dislriclo; The SlsJalas ilre rminly round in 
lhe Tumu dlMfK.1 and ram (If [he JirapafLamho\\lc lhslrll.:l. huwevct Ihesc clhmc 
~mupta~ intcH,:latcll 
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The di:strKlS Ire linked mostly by third class roads . The major road netwurks 
pt'OwM.ling communu;;lIion with the reS! or the coontry lIe the north·eastern road 
linking Tumu , Nnrongo and Bulgatanga rrom Wa 10 the Southern pan of Ghana and 
the other runs due Sotuh from Wa and connects the area Wllh the ,erural paris ur 
Gbana. A denscly developed network or foocpalhs linking villages 31K1 settlements are 
prominent. In the rainy season. some or the major motor roads Ind third elus road.t 
are MIAM:limes nul RKHor. . blc due to noods. 
A lafllc pcn:en1a~e til' the population i5 enG-aged chiefly in OIgriculiure &5. 
IIOUfCC oflivt'hhoud . brllllll~ ,lIkI <tnllilal husbanury IS t:ommon in Ihearc:a CfT'IPS 
!WChM)';un" . III;II/.c. lIlilicl. IiOrghum, groundnuls . colton and riccare(ulllvale..I 
Cauk. ),http, ~"a". ,mJ puultry are the anllllais reared for bolh COllllllerclal purpuscli 
and lIon)!!SIJC ":Ull'>UmptiOIl. C .. ule. yams and shea ~lIcr arc suppliN from Ihe area 
to ocher pam of the ":OUlltry Other people living 10 towns engage in ItalKllcrall~, 
wu.ving. leather taMing. pilo brewing and petty trading Fishing is also common 
ImOI1I people living along. tbe Bla~k Volta river 
Oct:urrclltcs 01 11"lh rumary and alluvial gold have been detected at Lawn 
~lId DUlin in the SIUO) .U'ca Junner (1935) traced some auriferous ql.larll vcins in the 
locality or Duori 
Guld ;5 also l:Ulnmon in alluyium ~Jong the Blat:k Volli down the vtc.inity of 
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Tbou~h Ilk' l."Conomic value or IIx ore found so far lIIay nol be pronmmg. it will be 
ofprxtical inlc:rest for investors 10 undertake detailed prospecting in lhe area. 
ManlCitnesc .md g"tphilc life re)oCrv~s art found al Kambale and on the Wa·Oorun(l1t 
Granitoic,ls occur In unlimited quantities in the arca and arc uSi.:d for roads alld 
other t:omfrucfion J1UfTKJ!oC:~. The establishment of a quarry In Ihe area parli(.:ularly 
.. Ionlille W.-Luggo and Wa·Bullinga·Ducie roads ror {he cXlraelion of quarry stones 
would bcccooomically viable 
Other mUleral rt" ... ,urcc~ In fhe ~(ud) area are chronuum and iron ore lucated 
In (he TUlI)u disfrK:1 IKc"'''C.I'IWIi) Concerns have been expressed in reccnt years for 
IheGoverrunent orUhanalobcginexploiling the Iwnore rcscrvcr. in the siudyarea 
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CHAPTER THREE 
~L_S.t;:r!J1ffi ANI> HYDI!9Jiml OG)' 
~mJJlliX 
lbe trgton IS generally underlain by crystalline bascment rocks which form 
one: of the main gl.."ohydrulugu: proviraces of Ghana (Figure 3) , TIlt rocks are mainly 
composed of ,rallltes. granot.huntcs ,nd granite-gneisses There an: lIIetamurphosed 
vukallM;S . .schists and phyllites of the Birinuan formation along (he western portion 
oftht siudy area. 
The uystalhne llolscutent of the Arm:"n conlinent is fonned by major suites 
oflhe Pncambnan roch The prC\Jominanllilhological types are granilic-gneisses and 
lowe'r ilrade IIIclamorphk: n-.:Ics lkri\'ctI from yolcanic and Sttiimrnlary deposits 
Amongsllllt I;lIIC:f.g.rttrulunc belLs.re cspet:lally prominent in r..ume areas . Large 
atUI of mon: le .. cnt .uklrugcmc intrusive rucks associaled wilh 1U3jor riftmg are 
inclOOttJ 
III Ius ",'Vto")', Roudakoy (19651 noted thaI the:: vukank and volcanogenic rocks 
Include greywackcs. fine tuffaceous sedimenlS and cherts rich in mang3111fcrous 
sediments . nICK lithologie) lurm a nonh,soulh beh of IUpracruslal rocks which 
execnd Inun IIIC snuth·weSl ur Wa to Ouagadougou in Burkina Faso. Plutonic tOCk5 
are the- muse aburklalll I~rc III 1Iac: area and are composed or granitoid rocks some or 
Whicb1ll"tconslderetJ lohc; I/ilrusives . 
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RuudD.ov (l96S) carried oul a regional mapping in the area ami explamed that 
the fine g~ined tuffogcne sediments prohably rtpresenf.S re'NQrkcd and primary ash 
deposits which occur to Ihe east 10 Bahile·Lambussic area. At lhe north-central pan 
in the lbolle-L..awra jlle.1 .lIe mafic volcanic rocks typkal of greenslone bells 
Junner 11t)35) (h\"lt..lt.-..! the IJlnml;tn !i)~ICIJl in Glum. . IIlIU two M:III.:·~ 
Lower ... JlIJ Upper lJlI Ulllall )oC1 ics Tr;)lditionally. Uppcr lIirlllllan JlII;l.:s \verc 
consKkred to overlie Ihe LI IWer Birimial1 rocks c.:unlormably. lJowc\'er. in a rt'\:cm 
reinterpretation of the str,ulgraphy. Leube et al.. (1990) recognised the two 
usemblages as coeval with the sedimentary/volcaniclastic units represcntin~ the distal 
facies. or basms tletwt'Cn ;J sequence of evenly·spaced volcanic.: bells . 
T~ flll:.11 Jjlhtllo~ics til the Lower Humlian include schists. phyllites_ 
grey ...... t..kc\. cryslalhnesdllsls.lulraceousshaleil.ndchemical (Mn·rich) sedllncllls 
lhalare largelyconfincd to Ihe basin margins. Thcseroc:ksilrebelievwtohavebcen 
derived from the Llberian·type of rocks as found in the nucleus of the Wese African 
Cralun Ilks-s.ulc\ . 1977) '-o"·..:r Birimian rocks are l:onfinetJ 10 the west of lhe siudy 
lIppt:r U.rimtan rucks .. ",Iude illI d)!<mblagc of Iholeillk ba!>alt:; with !lome 
Intcrnuw M:t..I1I1lCnlS TIle Upper Birimian 15 vulcanic In urr~1IJ :mu IS. cumposal tlr 
pyrnd .. sllt:s. tans. ~11I:.lIeJ \..unglome~Il'\ alld luHaccous !.Cdlnlcnls. The: ba"l~ 
\ okanrcs and pyrtlclastk:s hiIIve llccn ailcrrtllargcly to chloriliscd and epidoli.sed rlk.:ks. 
111.11 31C klosel, ~,uupnll0l!r:thcr U Jreenstunes (Kes"t'. 1985). The Tarkwaian resl 
ul1l:onformably Oft the alrinn;!" . According to Junncr (1935) the Upper Birimian and 
lhe ·hrk.waian a~ inter-Iulded due: 10 post-Tarkwaian ofOaenic activity. Tarkwaian 
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Imruslvc rucks t~ ~UP\ .Ih. ·u[ )C\<CIlI~ 1-":ll.:clll nl the area StwtaJ alk.! ;.,1:= 
,epre~m"'d tJy the ('''PI.' e, last Granite CtlUlplt:!C, Dlxco\'e Uranlte Complex and 
UntliffcrentiaLed ,~mlt'~ wllll.:h inlrude ark.! metamorphose the Birimian rocks . 'lbese 
rocksar(' uf Early ProterozoIc age, They form a large part or (he West Arrican cralOn 
IlXICropOutcxtCIlSIVcly in the Upper West region 
Cape CO;tst Urilmte Complex. denoted by (Gl) occur throuxhoul the eastern 
hillf of the: ilrea ;1II11 wnstltute part of the I.rae pluton th.t outcrup!> In the nonheast 
alkl MItJlh-easl of the region SUMller massives are founo ill the we!>1 ;md wuthwes( 
oC the are" surrounded by Luwer Bnimian roch 
I(ucks or this cumph;x. f.;oll5ist primarily of J.!ramtes. biotite and muscovite 
aranne. graoodll.Jrlle. pegmatJlc!i and aplite wilh biollle·schlSt pendants. TIle plulon 
is confurmal and hoInnunu.: tn the structure of the ",ountr) rocb Mi~1Il3liles and 
1)/1 Ill,' Il,"l~ Cli »tulllCs carnctl OUI 011 the m"gll1atlC rocks 01 the GralJllc 
('olll"lcx.c:~ f<lund In the pWJc:c.:1 area and in acJJUlnlll~ localuK:s. (Jubed3)h (1965) 
jllUPU~cJ iNffhe Cape Coast Gramte Complex. \',iI\ emplaced in four phases whereas 
the Ou.cove Granite Complex. was emplaced in UttU phases . Each compJeJ; is 
rn:u,lIIscd for Ib lreflll III lIK:rease in aciolty of rocks from the older 10 the younger 
phasc\ 
The Oix.cuve type wInch " usually called (G2) is composed of SOllie 
hlllnhklldc ·,:r,milC. granodiullie. dllJfltc. porphyry. ;lpJite and pc~mat'te. blOlite-
~ne," and porph}rllic biofll~' This complex room. oon-foliated. discordant 10 seJm-
dlS/.:onlanL bOl.hr.. In Ihe e .., ,;I05mg country rock.s whM::h arc generally Upper Birimian 
meU.\'uQniu 'oIouh numerous cnc:;Laves found within lhe granlle c.:tlmplc. 
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Uixcove gl1lMllUtds ;ue less widespread than Cape CoaSl gramtouJo; Typical 
massive outcrops of the Dixcove Granite Complrx is located to thr southwest of 
TangasLI and the cxtreme northwest of the Yaga . In the central and southern pans of 
!.he area. smallcr slUds ,""CIC fuUllC.J in Llmbonic. nonh·wesl and east III" Lawra, 
Babik and Uinfu 
The OJ gramtolOs are less metamorphosed Ihan (j I granites which are 
associ.ted with llold ,mncrnlization. n.e 02 type forms small inlilisive budies within 
the \'okanic belts (RoudiJkov, 1965). Where (aulls were detected. the granuOIds ~d 
~flcrt1.lcatadlslT1.lIIyloIllIIL;tIlOllaooscricltJzallUn 
Un(hflcrenllaled !!nUlllcS occur around Lawra, Nallllom and 8l1ufu. Apa" 
from thegfilnlhlUh auu Illlrusiverocks, small stocks ofbuic rocks in sume purlioru. 
of the lrea were vbloCf\'cu rileY mcluuc groups of gabbros. dolerites. norites Ind 
IC'rpenilnile5 
3.2 UI:t.rcrIJRAI CFQIOGr 
The: Lower PwleWZOlc 1{lI.:ks in Ghana h.ave generally been affected by two 
delullnatlon evcnls . DunnJ (he firs( event. the Birimian System WIS defunned and 
Illlrudcd by lCraniloids Suh~'quclllly, it was uplifted and eroded wilh the Tarkwlian 
Whl"h accumlatcd in I series or grahens and was located within the voleame bells 
The .5CCon.J dd\lnnallun even! imolvcd folding, ( Moon and Mason, 1967; Ledru 
C't 11 .• 1988; and l.eubect al . . 111901 and gravilY tectom..: processes which affecled 
both the nlrimlan and Tukwalau locks. Mcumorph/l'; locb of the Dim"i311 series 
lo~elhcr ... nh the ,nnitoNs whkh intrude info the UUlllu:m Ire (he ~t "urnmon 
ruc:b III Ihe 1>luJ~ ,IrQ 
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The milin reJirmal ~enlo~k:al and suuclural fealUres In Ihe area arc: Ihe 
Dornnun synclinorium and lhe Sawla·Wa anlldinorium. The Dorimon liynclilM:>rIUI11 
appear.; 10 be it large ~)'Ilchoal slructure Wit It a fairly gentle wc!>lcrn Ilmtl and a Sleep 
eastern limb . It plunges In a north·south direction towards the Babile·Duori and 
lIamik.8apalaarcOi (Rtlooalov, 19(5). 
l.:unslsh Ilt •• I,.lIll1hlll,lUnn III :-lInpil: h)h.h aoo extremely ulmplc,. II1l11ur UI1I:S with 
OI.mpllluc.h::- mCiI~uljll!! )<oC\CI.11 IIIcl~'r\; 01 :-y~tclII gcnerally tYPK:31 ul hw.:;th(1(J or 
Arcllt'lI and early I'rolcrololt foldmg (Pobcdash, 1965). 
r-oid S1rotlurcs Il.IVC III general the same orientation as the synclinorium and 
are en echelon arranged 1be extenl of fis$Urin~ and fracturing in (he rocks of the 
area can be linkcu 10 the presence and developmenr.oflhese !>Iruclures. Drag foids 
arecomrnon III phylhlnaoo phyllire·likeschisls 
The Tan~iII~ILI ;ukl tI ... DllrU1I11O faults are m:IJIlr raults which occur IUlhe area 
rhc 'Ink.:- uf 1I~ TallgOlslil 1.lUll IUln ~JUlh-wcslward beyond Kpahu ilOO Tallgasia 
Tbc: middle ~'tlon of the 100Uli IS eharatlCTIlcd hy myl('nHeS and caladasltes which 
have tJcveloped Within mClallIorphK: rocks. To the ea.sl or the faull. the: myloniles ~re 
replaced h) ~lamlC' nICks. whik lhe phyllonitcs are replaced by schists In the west 
1hc fault tlaycrscs nlCk.s ur the Lower Birinuan ~nd granitoIds of Ihe Cape 
Coasl Complex in the north . The Soulh western end cuts across Dixcoyc graniloKi 
maslaves whilw the inlullic ~tlon rum through the: Upper Buimtan. Pubedash 
(I %5). judging rrum lhe n~turr or ruck displaumcm suggcsted it musl be • luge dip-
.and ~f1ke·slip fault. wlrha youngcr age lhan all known pre-quater1ll.ry rocks in the 
18 
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nk: l)UfllIIUIi laull slnkt:s wulh-westwards (rom Tappo to Dorimon. Ofhcr 
Il' .... n:len.\lve faults well! r:nl:uuntcred near Vaga . These (aull lOllC~ occur within 
Inel.lllUUrptnc schim. 'nleY Ililverse rach o( the Uirimian series and granilokls of the 
Dixcovecomplc:x 
Field observations of 'rat..tuu:s and jo ints wele notICed on the ,r.,nites in Ihe 
vlclmly uf K.mlQ . 11tey an: oriented in a northwesterly dircclion . Veins in the area 
j:cllcr.ally show .1 nurthwest ur C'itMJlheasl tn:nd . The toniaCI of the veins with (he 
counlryrtl'eb;m:unevcnandindicalezonc:sorshc:ariIl8 
I'egmalilcs are (he moSI widespread rocks in lhe group of veined formations 
of the Cape: Coasl ,ramie complex. They are pink or pale grey in colour and ~how 
eoarsc·~rained PC:llmalllll': lextun: . Apliles are tjne-~falned and hn)!llIly culouroo 
rocks. They oUe dosely ilSSOClilll.'\J wilh (he pegmallle veins 
Quartz veills are very l'J.Imc:rous in metamorphosed Dirflnlan locb. where they 
are iD conlact with the Cape Cu~st ~raniloid complex. In the Bidmi'ln rocks. Ihey are 
a(ewcc:nclluClrcsluhuooredmc:lc:rs thick and range from mCIc:r!l 10 several hundred 
III some ponions ncar Lawr;ll. (lUll ('iralicl Ira versing 4uarll. veins were 
observed . In rew inscaoces, 4uartz~locks were delceled.ln the vicinilyof Jirapa and 
1>ouo. the.: "Iuanz VClIl\ alC numerous and associated wilh locally crushed zones. n.cy 
are plcvalclll "Iso willllil Ihe stretch of Binmian rucks (rom Dowcru (0 NamJum 
Nonn.JII)'. the quartz IS milky-while or hlul~h j!1r:)' In colour being oc(;a!tllllul(~ 
29 
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Uykes are a few lnelers 10 several meten in thickneQ and more than 300 m 
in eXlclll. nlCY are oUen h.KJnU III portions of rocks of gnmilold ..:omplcxes as weU 
u in Birimiilll rocks. Diorit.:s. diabase porphyries and dlabascs are often locared in 
mewnorpilic lUcks of the Biruni;.n series close 10 the contacts with the DiJ.cove 
,r.niloid wfnplcx J hey ~Isu form {j)'kcs and slrike nonh-e3sl and nonh·west. 'Ilk"Y 
~Iwayscutacross thcelld05l11t!-country rocks 
ID.'lmO(oEnl,OGlrAI.~  
(;~· lIerall). crYslalhne basement rocks have little interl:ranuJar porosity . The 
few r"res lhat .lre prcklll arc small and not inlerconnected: consequendy the 
..:rysUilIine rods have hllle pflmary penneabilily . However. considerable sccondlry 
pcrmc:abllily have heen dcvclOllt:d hy fraclunng :"!nd weathering. Most of the WOller 
iac:ry5Lalline rtlt..k .. is stored 100 IransmiuetJ Ihrough the wealhered lone near the land 
.. uff....:eand in lral.:lUlcs IIlI.k"Cptf. lesswealhered zones 
Gwundw~ter a,..-ull)ulation in areas underlain by cry!llalline rocks depends on 
lhe av~dahdlty of the thick regolith or the presence of a network "f fraclures. The 
nature and extent of fracluring allO innueoce lhe rate and pauern of weathering as 
well as the amoun( of overburden Ihickneu Malorno (1987) . 
OllSCflleni aquifers "t:cur wllhin the regolith and lhe fractured bedrock. rhe: 
mode ur Ul.:CUr~l1l:<: ul !!lOulidwaler III (he study area is controlled by the «:xter.t ;ukl 
erra,:. ur 1\ .... 1.: tkl.:tlmposlhun. the presence of quar1f., pegmatite and aplile vems 
wilhillthc:\k\.IJCIlIKtSC\J rock and 1111: prescrceoffrnluflllg and sheanng 
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III n"", cases, the extent and depth of weathering IS determiPL"d by the de,m: ur 
(melun"" vcmlngandJointinB· 
"hcgeol~K:al setling of Ihe project area is fairly complex and asa rc\ult. 
groundw;ilcr availability vanes constdcrably even on a very locI' scale . Therefore. 
where the re{tollih has adequate Ihid.ness (12 m·30 m). and the weathering profile has 
dcvdup..-d muu: lully III Ilk: fnnilaliull that arc shcarr.:d <JIll! fr:\lIUII.' J . sUflictc:1l1 
\upplics III walCI dlr.:nhtliinctJ . 
K;II:hh;r tlild 1I\lch (1993) I.!escribe fractured rock 0I4uiCcrs primarily on Ihe 
basis of wC"lherm~ tIlltt Ihn...: ZUIIe!>. llIunc:ly : Ihl' n:t;olilh. whele Ihe ruck hal breI! 
altered !>ub!olantially tOto a byeru. 100),1:. hJOker! weathered rocknmlenals near the 
surface. Beluw thr.: regolllh IS a layer of fractured and partially weathered rock that 
is rdeered to as the transition wne and below me transition zone IS the fresh 
WlW'tOIlheretl bctIruck whu.:h may nOI be fractured. 
SIU(lIcs frum Iilholo~lcal profiles 10 the area indicate that the tJcgn...: ur 
'A-C .. Ilk:lllIg III Ihe Iud ... deperuJs on their permeabllily . E\'alualiull :md slutHes of the 
drillc,~ lo~s t:~rncd uul Ic\"caJ that most of lhe WOller hearing horizons In the area 
uccur in (he IIIl.1l1cratdy da:ornposed zones wilh kw fractured zones . liar.ocnl!-
Yakuh" I JlJH9J ,Iha idemirtCd the moderately 10 poorly decomposC:d zones as lhe 
prodUCUlg. zut"!S inslut.hes in (he Uppcrregion 
lIu~'1er. (he walcr l)Carm, zones do nol generally follow lhe same liCqucnt:e 
in aU lhc botthoksdtllicJ . Scqucnt:esoflhe lithological profilCJ are likely Iu dilfcr 
due lu (f\c raitty complell natun: uf groundwater {,,:currence in buemCnI rocks of (he 
UppcrWcatrqiun. 
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Allhough Ihe verucaleXlclltllftacb lithology cannot bt defined precisely. the 
distinctions are u'idul for hydf(l~eologlc characterization. llJe regolith is derived 
pfllNuly from In-SIIU WtillhculI{!: of bedmck and to iI 1c'i!iCr extent rrom depositIOn 
of alluvium by streams ,md rivers . Fractures ori{!:inall~' In (he parent rock may persist 
in the rq:ulilh Pl.:tIIU:;lllIlity and purosity are usually provided by the pre~lIce til 
mlt:rl!ranuloar pore spat:c ;lIId as well tkvelopW by fracturin~ and wt::athcnnp 
l'rotJucing wells in (he lIpf"er West region "'C~ compk'tallllalllly in the 
modellltely 10 ponrly da.:omp!J\oCd .wocs. Where nUOlerous fractures, joints. quartz 
veins and r-={!:mautes OI..'Cur In the rocks of tile sludy arca, thick decolllpused lOntS 
exist iuld wtatilcrin#. l~ CnhalK:et.I ;Iltlll~ fissured zones . The decomposed wnes create 
openmgs hc1wecn the mineral grains along which [he wiler may circulate. The 
fracturt'5. Joimsaud veins aid ill walerlnlnsmission 
Intherel!.llIll. wiltcrtx.:cursatthemodef1telylopunrlytJc..-colllposetJzone. 11 lis 
c.lepends greatly un the PClru~I;lphit: composillon and mineralolY of (hi! rocb 
MKoKnJU' aoo leJd~lhic Sl.:hists aller hi days and permeability is JUluced. 
However, rd .. tlvcly hi~h yields are obtained from quartz·schisls in the moderately 
dttomposa,ltone:s. 
In the phyllites. groundwarcr oct:urs In fissured cocks and high-yielding 
;,qulfcf:'o iIIrc obtained ..... hen lhey ace compleled in fractured quartz veins. 
CIDAlGWSC (1'176) ICPOns Ihat lhere is no well-defined transilion from the 
dec.:unlptl\C\J rock to the fltsh balrtx.:k in the phyllites. because the frnh rllck is often 
100:. The dccomptt!lcl.l lUrkS an: usu.ally thick and vary (rom 6 m _ 36 m. 
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The lkcomposeiJ prooucls uf grecnslonc~ are generally fint: grained. rich in 
mica. c.hlorite aoo hornhlcnde. lbe: thickness of the decomposed 1.Oncs does nol 
usually exettd 47 III Agam. the water bearlll.!! capacity of the greenstones is 
cnlt1ncttl by shancretl (IUarli veins. joints arw..! fraclurc~ 
UNESCO ( 1'J71.J.IYM5a.bJ ~portecJ lhallhe hard rock Ilth(lI(l~ics have variahle 
yiekJs depcrkhn},!. un the HlI..k type GranllCs tend to be: relatively good aquife'l» wllh 
a tYPlc .. 1 IIIct.1ian yield uf 16 IImin. Gneisses tend to yield similar qUiUltitics tlr 
5OnlC\·:hatfes.liwithxhISISJ.ldphyllilcs. Aboutse\"enty five percCli1 orthc sucecssful 
wells were completed III I!rallItic tCHains in the study arca 
Reb!)",a!> .. 00 Cavakante (1987) report that tcrraJII~ composed of granite 
gneiss or other hi~h ~r3"'c IllCtamorphlc rocks generally contain more springs and lire 
more favourabk for dc\-eluprng groundwater supplies than terrains composed of 
schisUi 800 slltcs. Thele l'i rMI spring in the area of study probably btc<tusc of the 
pt"Ilhydrugeol~K"alc\llw..!ill()nscxislinginlhearea 
MUIt" ~ruunJwater I)I,;curs in caarse-grained granites anu ~rilrkJ\liurrtes U1.ln 
In fioc -l!raiRC)j m;ca and hornblende rich llranodiufltc:s. :tlw..! granites (CIDA/GWSC. 
1980) n. .: moeng·Ylkubo (1989) also made the same obstr"ation in studies in Ihe 
basement cumrle). rocks of the Upper regions of Ghana. The moM prolific lones in 
(he' I!I,lmtl.""' ;lr, Wm11lUIl where pegmatites. aplites anti fraclured quartz Vcifl' occur 
1"1 ___ JCI:I1"'p"I-.cll /\Incs in Ihc:§c rocks are nol up to 40 m . However. where 
~Janlll ... g.1k:1J.~J. I .... UIl. the dc.,\:t'mposilion pronie is not unifonn l1ceausc m,Ile 
rcsWanl poorty dccu'"l'u\ClI liI)crs are uflen deposited with less rCMM.ll11 11IVlkr;,tely 
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Yi.eJd:. are however l!l1h.mced III fraclured quariZ \eins and pegmalltu.: zones. Also. 
quartz dykes IIIINthng mlu Kh.,lS and gr.tnites develop joims during coollOi! . rhe~ 
joinlSarcahlelostoregroundwalcrandhavethereforcprtnCnlobeavaluabksuurce 
of Xfuuoow.llcr supply ill the sllKly area especially under unfa\'ourable {teological 
It is illlptnitive III glOulldwatcr U1vcstigallons to identify alkl cvalUiue che 
gcuh'~.1.: zones chat an: IInptlrl;1Il1 10 groundwater occurrencc . Studies in the region 
II.il\c uknllficd dua: types 01 a,!uifers. They are the fractured quartz vein aquifers. 
the Irat.:lurL'tJ rock and the wealhered zone aquIfers. These a'luifers may be inter-
relalw .nd hence produce sigl1lricam arnounls of water 
3.3.2 Cl1AJl. ,\l'JFRISTICS OF THB AQllIfERS 
11K: 0l0$I strlkltl~ h)Jrogculog/Cal feature ofaqullcJ!I mcrystallinc rucks illC 
theo. .. er. ... he:lmlll&variabililyoflheirproperties. I"tleyarehcterogeneousandlimued 
inarnlulcnt 
The h)·drilulk tundul.tl\·.ty oomully \·afICS wltlliO the sallie r(.X.:k uml ;Uld ofl en 
within ~hort distillU;:c~ . Rttem siullies by Gustafson ant.! Krasny (1994) explained that 
gouoowatcr lramiml,sioll IS by the fracture~ and joinls Ihat form (he cOn..!ucll\c 
openings Ihrough the buic.tlly jmpcr\"i"u~ basement rocks. Zones or incrta~d degree 
of frilclU(ln~ or trushct! rue!..) 11101)" xu as conduclors through (he rock 
WII!!lu(11JY2)repune\.!lhatbasementaquifersOCtUfWilhinlhe rcgolilh.nd 
J4 
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Their oc.;urn:lk.t' ,mJ characlenslll:s are disllIlCllve :md is lar,ely I 
conscqutlll.:-e "f It.: JIIfcr;u:II(1I1 tlf weathering processes. He further slaled (hal 
basemen! ;u~uifer.. are c!>scnflally phrt:atic In character. but respooo 10 IocIlbC~j 
absH'3Cli~n m semi -collimed fnhion if.lhe Sllllc water level occurs in ,I I~;O~ 
pe~ahlluy 11I'lIlOn SIK:h as a day regolith. • ~'I 
"""'''t~1 -
Aqullels ill the: Slooy area arc variable m clttell! and range from areas of tlcl.'p --
weallk:llOg tu (tlUlled and Iraclult..'tItuncs, llM:Y are usually , har:tCleriscd by low 
trall'JIII~ivilics v:lrying fr.)111 7,5 to 30 ml/llay alld low sloralivjljc~ ranging from 
3;0;10 ~ 10 811:10') KfI)AlGWSC, 1980). Banocng-Yakubo (1989) ~,bla lllt..'tI a stonr~e 
codficlcnl value "f2.87XIOI in a production borehole (4010 2) at Danko in Wa 
Aquifers (1)1'm i§Orated groundwater basins in (he region and (he: long.tcrm 
Slora~e capaelly i5delennined by the areal eXlent of the aquifers, the permeabllit), of 
thc~uirersilooU.es:IIII1'IIt.:JIIIIt.:klk""(Irlhea4uirers 
I{q:.ullih ;lI.lUllcI, \I{~ur more extensively where <I rclati\'ely thick and 
permeahle s.uurat ...' \l wt':JtI)Crcu l..une exists . 'I1le saturated thickness of Ihe regolith is 
a comrollina faetur un the Iranl>lUl\<h'lty, aquifer slUr.lge and also determmes the 
availahle dDwdown 10 11M: most productive aquifer horizon 
Chilton alkJ Foster ([992) reported that sa.(urated thickness in eAcess of 10 m 
need IU he available lor lile rcgnlith alone to act as a useful aquifer in lhe COlltext of 
a vlll,,!:c Willer supply, ThiS a!!r~'c" wilh the Ulurated thicknesses of regOlith in the 
study a~a which du nol 1.'.\l:cl.'d 2U m in most silualioru;. McFarlane (1992) ,Iso 
di5CUSSC1J thai such ~lIlIthtlllll~ are gmenlly fulfilled in the morc humid resions wilh 
shallow )!nlt.llllllwiltt'r t::Ible t'~p..'\:ially on the AfrICan erosion l>Urfac( where the dee-POI 
unlrHfUI \l.c:JlhcriIlIl- h.l~ ,occurrcu, 
l5 
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("rt:llcr;tlly . ~ulltr~ IllIIle ~gion are ..:harat:lcnzetl by limHetl areal Clltl=nl. low 
lran.\nll5Slb,IIlICS and low slol'1:~e capacities which result invariably in t:omparatively 
low yields. "Ole IhH.;kl~\s and characler of aquifers in crystalline basemcrK rocks vary 
wllhin short dislanl.:es depending particularly on the petrographic composition of lhe 
wd!o. their 1C\:lOnK: deformation. the type of weathering and gCOIIIUrphlllllg •. .::t1 
J{c!"h,II!!"t: til groundw:ucr forms the most effective and reliable means or 
sub~ur1ar.:c waler fe(lICl1lshrncnt In the study area Rainfall is the dominant source of 
recharge to the ~utfers III the region. However rainfall in the study area is seasonal 
and intensified by penooK: drou~hls. 
AlhclliC land u!>c practll.e~ such as poor rarming OlCthods. pasture ovcr 
grulll~ and dcforCSI<lllUn tll1ou~h rirewood exploitation, bush burning and cI};.rcoal 
bunun~ ~nd 1\1 a~~!I.lv;nc dc~rtlfll,:;,tion and eJC.pu!it' the soil to the :'ioI.:U!..:hlll~ SUIl 
Thnc adVCI'lol: cllC\:h billie .• houl !>CrlOUS cnvuunmclll,.1 coosc4UCnces luch ill $n.1 
erosIOn, local chnlillt..: dlOln~es c!opeclall), high evapolr~nspirallon as well as insll.bility 
.nthc hydrologtcal regime and thcdestcuction of wlter bodies. 
In the study area. the hiJ,hly d«omposcd matertal which overlies the aquifer 
\JIU;' frunt silty !.and and lalentn 10 almost pure clay. Hence infiltration IS usually 
\uh~t.illnll.illl Ih'tluj.!lt the silty sand in consMJerably largc areu. Whcrcils III zones of 
high dl1 L11IMcnl. very IIUle do. .... n. .... rd percolallon can take place and the ma.n 
rtthilr~c IS alUJlI more pennc.lhle zones ilOO fraclured quartz veins Nonnally 
.nlrliratlon is redocC\l by s(JlI..:ru~lfIIg 
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Soil ftJoisiure slUragc is also reducetl by the erosion of rUler grained material 
resulti ... in tbe hindr.tlll:C: of downward percolation of water. Groundwater resources 
of basemenl rocks strongly depend on rt:charge to the groundwater syslcm and 
ciimaliccoooilioOlo. Climalic faclorsconlrol precipllfltlon, lemperature distribution and 
chaDl.:tcr of nICk wcalherinlt in IhI: long·tenn perspective. 
Gcner..  Uy, recllarlCc to Ihe m.luifer systems m the Upper WcM regiun is small 
and hlllllcd but ~1~IlIIIL:alll hC~<luse of the barner normally formed by Ihe overlying 
dayey dc(.omplJ"t·d 7tlnt""~ ;u1t.l evaporation. The basement rocks do not have high 
groundwater stora~c:_ Retention possibilities arc limited and ltrountlwaler is rapidly 
depleted. However. the: presclll:e of pegmatilcs. shear lind contact zones . fraclured 
quartz veins aoo lhe e"IeRi and eUecl of deeper rock weathering. aid a lot III 
augmcntin,theltruundwatcra\'ail:ahlilty inlht re~i(lll 
CIDAIGWSC (1918) ft!ptJIICU (hatthc quantit)' 01 groundwater rcplclllshmenr 
in thc rrgiontJepends IkJt 0111)· on thc 100ai prccipllalion in a given year. but also upun 
soil mOIsture t;(lruJUIOns before a sionn and lhe manner in which Ihe rains occur. 
Rechaf"Je (0 the aquifer bc:~ins to take place only when the moislure deficit in the soil 
has ix.'C'nnlCl 
Estimates 01· dileel Ic.-.:h.nge are likely (0 be more reliable Chan those of 
mdirecl ra:ilarl!e. Lemerel al (990) are ofth.: opinion thai since recharge tends to 
be correlated with rallltaU. short periods of heavy rainfall within the year arc mOR 
imporlant 111 pmdu(;lI1~ rt'Ch:u~e than many years ot avera,e rainfall. 
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th tar as (he hydrnlo~y of the African ba!'oClllcnt is concernt:d the climatic 
\laIMhlcl> ,If ramfall and potential evaporation are the most si~niricant factors in 
delcrnlllilug run·oll and ~roundw3lcr recharge (Farquharson and Oullock. 1992). 
The study arca i~ characlerist.'1.I by a cyclical aMual weather condition with a 
single rainfall period from April 10 October and a mean 8lUluai rainfall between 900 
mm and 1150 mRl. Tlus is followed by a prolonged dry season. The potentill 
evapou;msplr.uion is very high. Pclig-o.a el al (1988) eSlimate\l an annual potential 
e~apolr.lIIl>rlfillion \'aloe or 1726 nun lor Wa_ Relali\'e humidity is high in Ihe rainy 
SU50n and low In the dry .seasun 
rile ~luiJlc, of Balk)cl1~- V'ILubo (1989) in lhe basemenl complcx rocks of (he 
Upper ICl!IUII ul (jllilllOl cl>lIIuOItctl lhe Ilver.ase annu,,1 ~nlulld\\ aler I't:t"hargc 10 the 
Lawn' drainatle bolsin 10 be 1)8 IIl1n Hc c~plamcd lhal thiS amount of' recharge is 
expected 10 aupncnt the gruundwalcr base of the siudy area 
Parry et .1 (1987) di~usliCiJ Ihal au <I\"crage rechar,e rate eSlimated between 
two and thrt."C pcru:fI( of Ihe allnual rainrall obtained from the limited infonnallon on 
urbanbureholcflcldsinlhearc<I. Walcrlevcl nUCtu31ions ina nctwork or ohscrvation 
wells are depcndenc on the limin~ afIIJ inlelUity or rains <lnd lhe local hydrogeological 
5Cllingpn:v.uhll}! In thcarca 
When: the mcan annual rainfall is less than 400 mm. recharge from direct 
mrlluailull is likely In be »Ina II or negligible (&imunlls et al. 1988). Thererute 
groundwater l'CSOURC!> ale ollly likely 10 develop in association with runorr either in 
allu~lum (Ir ulklcrl) III~' h.I~III~·1I1 lUcks 
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Annoal rC'\:harge of grouoow3ter 10 the study area IS significam but of local 
orl~lIIandn"(.5UPf1ltedbYlnydis{anlsource. Akiti (1976) discussed thai groundw3ter 
In parts of the lIpper Region arc (If recent age and charactC'rited by an active 
i!«HJoowlotcrdrcul.llOn. 
I lie I" (1937) polllfl:d out thaI unless and until withdrawals of groundwater arc 
balanLt.-ubyanirueascinn!1:ha'l!eorareductjoninnaturaldischarae,w!terwill be 
removC\l from storage and water levels will decline. In the Upper West region. the 
ahstrOlction rate or water from boreholes exceeds the recharge . This accoums for the 
reglllUlldeclineofwatcr Inels in:hc reglOlI. 
1111.' II\CI,III I'.IIICIII I" gruundwalC'r 1111\\ 111 b.l~clI\cnl lerr:lIlI:- I:. conlmllt.-d 
prunanly by lhen:J!.loROllll.lpOll:r,lphy.ndgeology. fUlidalllel1lal wany gruundwatcr 
stud)' 11< all ~dC"Ulotc ulK.kr'lalllJil1~ of the geological cooolltonsprev;:riling in the.re.I . 
The p.:a11C'nI and r.lte of gruuudwalC'r movement within illl :trea is gon:nl(.'lI nul only 
by IOpof.raphy. but hy the rock. 'IIU~'lures as well . Particularly the laull and fold 
pauernantJ its mllucnec on rock Iraclurlllg 
The study are .. is ulllJcrlaill by hard rockSCOfl§iMlIIj.! primarilyofgranilicand 
UirUIU,1II 1I'ClarnOI plilc rocks. The: granilic rocks comprlSC graIlIlC~. grllll"",luflles and 
gramte ·llllei.s.scs. 111(" Ullllllidn rocks in the arc .. arc SChl~IS, phyllites. greclUConeslnd 
shean.'llcungJnmeIOlICi. licltCfally. theserock.s have virtually liuleorr"'pcnncabl luy. 
el.«pc.lRplkC$'NI~lheylirewC~lheredand/orfracrured. 
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Tht: BIt/lilian HK.:ks III tbe region have been highly folded and onen sheared andlor 
faultoo Quanz "":lIIin~ is common In the SChlslS and phyllites. TI"IC'y arc usually 
deeply weathered alld IIIOTC nutlccable in valleys and tlalterrains where intcR.'live 
frac:turin,and shearin!! h. . , II\:~um:d than on hillsides. 
In the crystallmc h;t~lIIenl aquifer". groundwater flow Ul.l .. UI~ I:u~cly through 
dlsc,:Olltmultles "he nature ark! llrK=nlalion uf these discontJlluillcS ,lItJ III 1I"1C' 
IXcurrence and movcment (II ,:ruundwaler. Ihe permeability or the ruck.s and Ihe 
stora,e capacity "f the aquifers. Generally. discontlnultics and shatter or breccia 
zones a~soclalcd wllh laull!> lorm irregular alkl lOrtuou5 now channels which may be 
rtlled with permeable or il1l~rmeabJe materials. In some rocks they may be locally 
eniar,edbysoJulionlofomldiS(rctctlowpalhs 
Fn:Clc ana.! Cherry (1979) noted Ihal groundwater now occurs [rom tlk!' 
hiJhlalllIs t()ward~ v111eys The .l!ruundwatcr now s)'stcm In the region consists mamly 
or rt:charge on local wpugraphic highs and discharge in lopograrhic lows. 
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C'IIA£TER FOVR 
4.1 AYAIJ«U!LE IlA"H 
InluIIIW(jOIl ohtained aline lime ofcunslruction of boreholes was extracted 
from the archives hdd by CUIIIIIIUIIIIY Water Project (COWAP) uffices in Wa. Otbers 
wereuhcained lrumlicldsludiestluringthcsludyperiod. The illform3liunincludcd; 
conslruction cktails. lioIalic and dynamic waler levels, lithologies. yields and 
topographic locallUII~ 
In IUlal, n:cun.ls frum one hundred and nmety two boreholes wen: analyzed 
for the study over 1m entire region. Among thc:se were twenly thrfC observation 
borc:ilI.lles and one hundred and sixty nine production boreholes. 
Oon:OOlc recorus wele analyz(."t1 and estimates of borehole depths, depths to 
Iopul a~uifcr. Qvcrburdenthicknesses. borehole yields. and aquifcrthickncs5Cs were 
ollla.ned Ilowcvcr. six hun:holC's do not have records pcrtainin[lto boreholes dl!pths 
allli uverburden thickuess.c~ In'onnatloll was abu obtained on static WOller levels (rom 
one hunrJu:d and seven boreholes during pump installations. One hundred and five 
borehules ;lllttl had slalK: Wiler level meuuremenls mken during the field studie~ 
Availilhle data shows thallhere had been one hour pumping tests dilta for 
forty-sevell horchulero <II the time 01 cOIl!iIt'Uction, and twcnty-four hours pumping IeSls 
were conduclal on Sill uther bordklles in the Wa well field51 during the ~tud)' The 
Global PO$iltt",in,r Systcm was used. to measure the locatiom and elc\·atiom. of 
obscl'YJllion and pruductumborchulcsduringtilcSludy. 
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III ,II] .U1c=mpl (0 provide clean pOIatJle wale r in the Upper regions o f Uhana. 
(he C.,.han loc<:m.l(imui Development Agt'OI;y (CJDA) in conjunction with the 
Ghan:I Wate r and Se werage Co rporation (GWSC) drilled 1,018 borehoks in the 
Upper Wesl rcgion 1ll0IderlOeradJc.alewaler-borncdlscascs 
Nutably . boreboies with low 10 mooerate yields were pump testeO for only one 
hour. In weh Mluallons. wdl cllll': tcncic:s and susutined yieh.ls be(ome unpredictable 
aoolhe rcspoIL'>C\ Olthc aqullcrJn: usually lumh:d 10 only areaslha! are milucnced 
by the cone ofcJcpression for (hal period onl) 
Oue lu P'O"r slUrai!-e (oooilions and old a{!e o f the dala . some WI illngs on the 
borehole logs IlOKJ lalkd ;uw were illegible . giving rise to poor qua/ily data . The 
pouitJdllY uf drillers making «.:OInl1lul1 errors in the meaSUlemt'nl~ ;lUd c~IIRlalion uf 
borehole parOlll1lelcrscalllkll he ruk-d out. This rendered Ihedala unreliable in some 
Slcr·dlOlWtJUWII ;uklll'n. . (;InI discharge tt'sts "L're t:arrlcd uul III Ihe Wa well 
fields wllh Ihe Kuma"l dnllUll! Icam IIf the Ghan.l W;uer and Sewcrat:c Corporat ion 
durinl! the 'fWy · The: cuml,ul! discharge It'!ols lasl('ti twenty four hours with Sil hours 
tn:llvcry Dte: Mell lIrawdu,",1I1CSIS were carried oul for one hour per SI~p for three 
"Icps. HowcH:r. due 10 variallun~ in well discharge!> a, the pump ildjusLS itselr 10 
c,;tgnj!l"I head. early limc daca an: not accurate. Therefure . tuachieve belterresullJ 
lue 11K: §tq>tnls . thc rullll'lII~ pcrllkJ (or each SlCp must be lonaer 
Comtr.unl, "Ul.h .1 .. 1')):I~tie~ ;and inaccessibility to wme of the communitieS 
due to the early rains nWde It \hfht:uh for rleld siudies 10 be undertaken III lome parts 
oflheqlOfl 
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lIowever, rfCltlworkw,. . n!.:ooedloallthe""enIYlhreeobservatlonborcholesfounti 
in the five diSlrK:ls of the reviull 
III an)' use, RIlIW,' IIf Ihe tlhscrViltiun boreholes was pump I(stet! lu u)ldal(, 
hurehuk: cundilions dunn~ the t:OUISC of study. The inabilit), of Ihe Global Posi"ollln~ 
Sy!ilem (GPS. GAf{MIN 7~) 10 IUfK:llt1n was a drawhack 10 ohl<limll~ ,,,,urale 
localiunsoflhc btlrehuh:, 
I1lC m~1 common fonn ul ",ell Icsling is by pumping waler IWIlI a well and 
stUdyin)! Ihc 1~1nsc: of the water level within the well .uKl Ihe JJJ,lI.enl parts of the 
aquikr 
rhe ... (1940). ,IOII1IL'\I uutlhm the response: 01 an aquifer 10 withdrawals from 
wells I,kpclllh lUI the ';Ile "I cXp;lruion of the COlIC of I.kpression cau~ by Ihe 
wilhdrawal ut \\.tlel lh,~ further lkpcnds on (he IlanslIllssivily and sioraae 
eoC"fficu:11l ul Ihe "quifer, Ihe d,<;I;mce to areas in which waler dischar}"!cs naturally 
rroMllhcaqulrcrandfillflllyolllhedistance1orechargeare.as. 
Under 0.1111r .. 1 t:Ulk.hlu)fl(, II'el a !>ufflclenlly long period of time prior 10 lhe 
aan of willw.lra",,,h. Ihe J'~·h. . Hge from every groundwalc=r ·,y~lc", equals lhe 
rt'Chlr¥.chlll. 
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IllCls(193Slutllill'\J,m;millni!yloheal nowlheory IUilrrh'(";tlananalyltc:t1 
$OIUIHIn . ThisanoalYIk:all'ulutlulllakcs inioaccounllherclaledparalllclcrl'uflimc:anIJ 
aquifer SIOB,I;. flis SOIUIltIll, in lerms of drawdown i~ 
"herc' - lh,l\vJm~1I (m' 
U.~ t4.2) 
S :< ~hll,lgC 1.,Jt:III~ 1~1I1 I dlillclI\ltlulcss) 
I IItlte Stl .... ~ pUIIIPIll~ ",!ltnt (days) 
rllCvaiucot thcllltc8r11lequaltolllsgiycnbyaninfinitemalhcmalicalseriC"s 
thaI Theis exprcs."Cd as WfuJ knnwn as the -Well funclion- of u, and the equation 
'ImphfH:SIU. 
S.~It(UI 
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EquatllJII ,4,1 J is knuwn as the n.eis Non-Equilibrium equatiull 11115 equation 
generally pernllts the dctcfIllilliuiun of the constants S and T by conuUl;ung pumpmg 
tesl fur the wclls. ur If the cllmt;lIIts .. re knuwn. the drawdown can he computed fur 
rhc denV.ltltlll or I hc.~ formula is based on the folluwing assumptions 
(John\(JII.1972). 
nit: waler·bcalllllZ funnatlUlI I!- ulllform in character ark.! permcable: in boUI 
horrlUlltal alkJ vCIIK:al di ....' l:lioll'; 
2) rt)C fOllnaliun h. .... Ullllurm thicknc"~ 
3) rhe Immauon holS mluute areal extent. It isconfmcd, Isutropn::. homogeneous, 
aooisfullysaluratcd 
4) The lonnallOIl rct:elves lUI n.:t:harge flOlIl any source 
5) rhe pulllpt.-d well penetrates and m::CI\·CS water rrom the fullthickncss or the 
"alcl'·hc;mnglull1lO.ttun. 
I'I)C\C ,lSMJmptiuns m'c rarely mct 111 practicc. For the sulutiun til' any 
~1{lUlklw.IICI pruhlcm, idc .. li\;IIT<'llt,f,hc aquifer and boundary cmkJitiulls of the now 
... ptCII1 IS Itc.'\:e~ry. Ihl\\CH.'1. .llllorlllulas for the analysis or pumping lesl data are 
ha'-CJ on ~cllam d."'SUlllpIIOru and a:cllcralization. Erroneous results of Ihe (;Ompulation 
-( 1\\.11 .rull~ ~ halaclCII~lll.:s (If an .14ulfcr are sumetimes ascribed 10 irk:OIICI.:IIk!'SJo. 01 
rhl" fUIlIlul:. .ll'plicd, wh .... 'c;I\ thc a..:lual cause u(error is thaI. Ihe field conLiilionsdu 
Hut SOIII"ly Ihe ;"'~UlIIpIlOIl' 1111 which the formula is based. 
There an: two lyJlC" 01 pumping lesls, the constant dl"Charge and the slep 
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1be constant di~har!!t (c~t involves the use of a caRlrol valve to maintam the 
dlSl.:h:Jrl!cralcthruughoul the pumping period 10 a slipulated rangc which m ust be less 
(han plus ur minu.. . tiVt: pcn:CIII uf the chosen rate. The step t1rawdown Icst involves 
pumplflf! a well al an inilially low rate for a perioa of time. The discbarge rate is lhen 
increaied thruugh a succe!i.'iivc ~ries of stcps. Graphical methods attributed to Theis 
(1935) and Cuoper·boob (1'146) have been used 10 analyze pump test dala for this 
study 
CU<'I)C! ;111.1 J.tcub (1946) sug~ested a simplification of the 1bcis equation 
which dispenses 01 the need for type curves by utilizing a semi-logarithmic plot for 
thuse field data where u < 0.01. Deyond, the first log cycle of time usually gives a 
strai,hl·JuM:rclatioll\htp 
nus expresslun is cUllvergenl for sllIall \ alues of r and large values of t. u 
is small. so (hat tbe !.Cries terms in equation (4.4) become negliJ.!lble .ner the first 
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Sub~i(ulins roru IIII!l{U3110n (4 .5), using equation (4 . 1) 
(4.1) 
s .. ....Q...(ln~!!:.-O.57721 
41fT cJS 
A ploc 01 dn.IoI.'down. s. versus the logarithm of (fOmlS a straighl line (Figure 
4) . The ~tJ';li~hl line IS pruJccltd 10 jnlercept (he time axiS ill 5 = 0 and L = ~I 
Equation (4 . ~) Ihe:n bt:t:llll1cS 
If II~, "" 10, then Itt~ til" ~ I 
hence. s can be cxprcua! by the l.irawdown per log c)'cle of lime a.~. lheref'lf'e 
T" l....:l£Q (4 . 121 
41f 6.s 
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Cooper - Jacob Solution 
/ 
10' 
FIQ . 4 : Time - drawdown curve for constant - discharge 
test, showing Cooper-Jacobi, merhod 
48 
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In the Coopc:r·Jacub Illelhod of S(1Iulion. the: same assumpllons as lor Ihe Theis 
melhod :ihtlukl be sati~Jjcu. al~) IIIe value oru is small (u < 0.01). i.e. r is sPlall and 
( is I'Jr~e: I I...: ... orKlllln!! [hOlI II IS small will be: satisfied in confined aquifers for 
moUcrale iJislaPl.'Cs from the: pumped well within an hour or less. but (or unconfined 
c:oOOIlIlIll..\ II may Lake: I\H'l\e tlr 1I1(1r(' hours of pumping. T~ Coopcr·bt:ob ",('Ihod 
is u!>C\llo tklL"\:1 iIIk)l11aln:), IIIlhc aquifer \ul.:h as aquiler dewaterlnganl! n:spon.'il:s 
After pumpln~ has been shut down the water level will stop dropping and 
iDilead ([!i.e al!aln Lo its onglO:!1 JXlsitll>n. this is the -recovery- of (he well . The 
fttOycry of the well ~Id behave as a mirror' "lIage of the: pattern of iJrawdown 
rcganlk~, 01 Ihc type 111 ••q uller L:olw..litiuns and thus can be used as a du:ck Oil those 
aquifer pwpcrll~ dC':lculIUlCtJ from the drawiJuwn data 
llx: nse of the WoJlel Inc! IS IIIcasured iU the residual drawdowll (51) (hal is 
the: dilfc~nce between Ihe uflJ!1I1.11 waler IC\'cl pnur to pumping and Ihe aclWlI waler 
level lnc:asUn:tI ill ac:crtalll IIIOIOCni (l')sirv.:e pumplllg stopped (Figure 5). 
When: Ihe rrc(,:c .., hllg pumping has heen IIf reasonably long duration, the 
~siduaJ dr;rwduwn mClhoLl IS IIlllie appropnale . In this case. it is essential 10 know 
the dur.ttion lit rUlllpll1~ (0 flflllr IU t:c:swllon as wdl as the depth 10 wiler II 
succnsivellmc IIIICI YOIh;aiterpumplIIghasceased 
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~- -Recovery Penod- "I 
Fig.5: Schematic time-drowdawn!reslduol drowdown curves 
(ofter Krusemon and de Riddu,1970). 
50 
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The data obbinttJ duri"lllXovery pennil the calculation of the tramulIssh'lly. 
(hus t:ivin!,! a check 01' rhe results of the: analysis of the data obtained during the 
pumpingperioc.i . .\ -101"1.'0\· ... 1 . (hcla.:o\·cryn~lhoohaslheadvarMagelhaltheralcnf 
ruhirge. Q is cunstant and cquallo the rate of discharge Q. during pumping "n,is 
meam lhal dnlwOOwn variatiHl" resulting from slighl differtoce!l ;n the rail: uf 
dlM:lrarf!cduring r"unplllg(.[u Ill.lll)(l.:urduring recovery Theis recovcry methud call 
he used 10 calcul.uc the Ir),drau lu.: properties of an aqUIfer If the ;, .... UlI1ptIUI15 :lIkJ 
COlldilion." u'-Ihc Cuop. .. , ·J:II.:"b lltelhod art ~ali~lred 
"11K' reSidual drawdo~'II, durlll~ tile recovery penod. according 10 Theis (1935) 
I ~ l!u'l,:n hy 
~1 
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The slope of a straii!hl hi'll! lruUl a scmi·loprilhnuc pa[lCr. wllh Ihe IIIIM: absds~ 
1'C'fl~lttj"g""'II(lIlII/(llIfOIWlllhroo}!htlM:polllloveralol'Yclco(tlll . .lslis 
given by 
rhe value of S (~loraliviIY) cannot be obtained from this methud In the study. 
these 1'10'0 methods of sululion were used in deICrl1\ill1n~ lhe h~Jr.IUIII': propcrtlc~ 
Spc."'I:irK: cap;II.I(\' 1\ (he tefm used 10 deKrlbc the ylt.'IJ per ulIllllrawdown It 
SpecllllllpKity = Q/5 
~ = drawi.k'Ydl (nil 
SpecinCcaP;K:II} h .... umtsofmt/day. Any specirtc capaclly value should he 
eltplc,,~ relative 10 .1 lllllllllllli time basco Thus (Q,Is) would 111('.111 tiM: previlliing 
abstrdClIon rale divtdcll hy Ihe lotal drawdllwn afler pumping for one day. and could 
he diH(~nt frum tilal dcll"llmnctl afler I duratIOn of pumping for one hour or one 
52 
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The qx=cific capadlY of a well decreases with lime flu a ,iven rale (II 
tllM:ltarJ.!c. () . Since drawdn\\f1lnt;re3SCS with limt'. the: ~rcciri' ,apacily of a well ." 
mdepcnJcl1I uf the dl!'.t:har)!c rAte: as lon, as there are no well losses 
rlk.' C((I\:U:/k:Y .. I ,I well IS Ih, nujo of the actual specific capacity 10 Ihe 
Ih,oll·,,,al S","'Clril. 1.:"IJ,l \. I/~ of the well . Faclur~ innuclX!jng the aclu. . 1 specific 
,apa,.'), mclude the hyllrauh, prupcrllC~ HI Ihe aquller (coerricienl s IIf tran"lIl1sslvilY 
antJsto ralC),geololZlI. . NJUndaricsul Ihcaquifer , tilepa"ialorlotalpcllctr:tllulluflhc 
a4U1fcr. the el"fC:C:livc: ol"ell :m:a ul the well screell or rcrforalct.l t:asin!! . duratiun of 
pumpUI)! and pumJljn~ l:tlc . 
I{cllahaugh (1953) rtx:o~nized that Wt'll construction .111.,) development Ire 
IllIrtIJ[;UI[ and atlc.:cts Ihe prc:t.ht:llUllS of total drawl.lown and con)Cquent C~'lmates or 
weI! dItCICIICY. According Itl Ulersc;:henk (1963) the errlclency of a well is governed 
largely by ,he m:lJ!nitul.lc of well lou and Ihu'i fall~ off rapidly as tli'"'h:n~c i5 
HtcrcOl!tCtl The elrM.:lcllI,:Y 01 01 "'1;11 III ;til ;U.lulfcr h:wlIIg a hi~h [,.III~lIIi~SIVi[y IS 
alrc,,-Icu hy well loss tll.' f:lealcrdegree Ihan thecfflr.:icnq· of;1 well in an aquifer 
havlllt! a Inw 1t2m;I1US5IVlly. ;uttJ il is lea';l aff«lcd hy paccial penetration of aquifers 
Step oIJ\l.llu"l'ou tc~h IIIvolve pumplllj! a "l'oeil ;It an lI1ilially low rate for _ 
pcrMII..I ur lunc . The "' •.. ..:har),!t! rate is thell IIl1,:cca);Cd Ihrough _ successive serin of 
,;tcp' ·Um.-e \I"-'Jl!o arc ;11 Ic.,,' I"'quired for the analysis of !tte:p·dcawduwn teR lk 
dr.l .... ·duwn and (he C('"c~p',nding measuremenls of time are l'C'ConIat (or eKh SCep 
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The efrJCN:ocy "f ~ well can t'Ie expre~KtJ qU;lnlilalively by idclillfYln~ ,IIIIJ 
detenllllliuJ,! the scp..u:uc components of the tOCal drawduwn S" = S~ + S~ 
Where Sa is that part (.t the drawduwn due tu hlnnation 10$5 and S .. represents that 
PM! due 10 well lussc~ 
The rurmatioll I"", 1.:1I111J't1l1C1lI arises from the re~istance of the waler-hearin!! 
rormatltln and is proptlflllll",ltu the discharge . II IS .,Isu termed as the :t4uifer IO$.~. 
which 1\lheineviIOlhJcIt",uIIICOIdduc:tolal1l1n.ullowlIl water through the 3lJuili:r 
Wc:1I 1m." Icprc~nl~.1 IUIII.:IIOII of lurOOlenl now within the well ilud "dJa~elll 1""15 
or the "4uifcr. Wclllos.~lI (,;;111 I,.,' 1IIIIIIInized by auequate and proper well design . In 
tJUs study. Jacobs graplll(;al solution method was adopted for the analysis or step-
dnwduwnresults 
Jw.;ub tJ947) dc:rivcJ Ill ... C'lIMIIUIi 
S. aBQ + CQ-. Equ;lliuII (4 .15) 
where B (m l dlY) ilnd C (Ill' dOlyl. ) arc: aqUlref 100 well loss cunstallls Ic~p"."Clivcly . 
Q c thedl~hari!L: I,I'~· . 1111 .tay) 
n =. variablc:exponcnt 
OntllCassurnplln""IMlluflurl;1ulenlflow.lossesarcrc:latwappruxllIlately 
to the square uf the: dl'l:h.u,:e Jacuh su~!!eSled a value of II = 2. This enahle .. 
SlInplltKalM>nOrequilll\lllt4. IS) bydivkling tluuuSh Q50fhat 
S.JQ. = 0 + CQ t.:A.IulllUn (4.IM 
'('be p,aramctcrs U .u\IJ (' c;m be Jc:teOluncd !rum a graphical method hy 
plOIlIll': 5./Q :agaiO$l Q, C I~ dcternunC\l hl)m the slope or the line of best fil throuJh 
the dall poinls and B is calculated rrom the tmetccpc on the S.JQ axis (Figure 6) 
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/' 
~SIOP.=C 
oLo----~---41ILO--~6~--~~O--~I~O~~I~-O---,~!O~ 
Q.(m' /day) 
using Jacob's method . 
55 
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prt~lIt study. The: lithol{)}!.I~.;tIII.gJi aiOed in the determination or the IiUKlh>l-!Ics in the 
boreholes. overburden lIuckne~o,('s. dcp(hs to top of aquifer, aquifer thicknesses and 
borehnlc lkpttu , Fractured and veined zones were all deduced from tiltS<: lot!s fur the 
obserV;lUI)II and pflldu~tlun hurehoJes. A summary of borthole and a4uifcr 
(,harJ~IC'I'I'~~ I' ..h owlI in Table 30 
Two Iypes of pul1lplng lcst were used for the analYSIS : COllstant rate te51 ami 
$Iep drawdnwn analysis . In the constant rale pumping lest, graphs uf drawdown on 
the nurmal scale: agalOst lime on the loprilhnm: kale \\crc plonC'd 10 dett=nnine the 
papt, lie III mosf cases nil a stral~11t Ime for cach tlraph plultcu IJC\ 1.llillllS Irlllll :'I 
\Irollghl line plot arc usa] In delmeate boundary t:oooition., and olltel mhul1Iogeucitics 
IOthca. . ui(er. 
Ute C(l(tpc'r·J:tt.:uh 11946) method was used 10 31l11yse dall (rom one hnur anti 
Iwenty t'our pumping test tlata Thc (we-ocy four hours pumping lest \1,;1)1. perf'onned 
In p;trtsoflhe Wa well fields on Silt boreholes. dunng the study with the G.W.S.C 
tlnlhn~ unn (rom Kumnl. No data was available on 24 hours pump lC~1 (rom the 
e;ltISllIIg ool't'hole lop for Ihc PIOIct:I. HOwt'ver. one hour pump tC"'lb were t,;ondut,;(cd 
rUf I1IUSI or the burtho'n dUf,"!, pump installation. 
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rransmissivilies were C(lmpulct.I usin,g equation 4.12. No storage I.:oerrtcicnl 
pat,uneter was c.lcul<ltetl . Sf"II..·uhl.: cap.1cilM!"S Vr'tre delennined rrom the wnsL1nt rale 
pumpHll,! resl d:lIa rorone IK>uraoo Iwelll)" fourhc"lurs: IIIlhe borehole!(studietl . 
Re~ldual drawJuwl1 1o.1Irves wele drawn from the recovery Jala. Thc residual 
drawdown, s' was plotted on the artlhmcll4.: ~"Ic while the ratiu u( III' was plouw 
oa. In,.rilhmic s..:ale . ·11"M.' lI"I1~IIU~"I\"ilics were Ihen calculateJ uSlIIg 1-:4ualllll1 4. 14 
The fI. ." \:uvery method was apl'hct.l In only silt hOiehok" III Ihe Wa well Held .. 
All Ihe bnrehole and a4u1h:r parameters. as well as the time-cJrawdown and 
resMJual pl~s 'ken.' cunverlcd 10 Ihe SI unils rrom the IItlpcrial unll~ Only five of the 
wells in the W. well rleld were rested by slcp-Jra\\·Jown pUIllf'inl! 
nll: leSi was performed by pumping: the wells at various discharges by 
locrca'"1f.! Ihe dischl~c BIC in a step-wise fashion . The pumping faIt's wc,·c carcfull~ 
n:~ul.llcJ .1I1d waler levels nte .. ~rC\l Jccl.lIalely . Ollt: sholfeomin, encounteroo wa:, 
Ihlllhc (lUl1Iplllf.! 1;lle wa~ either Increased urdccreased on an irregular basis so lilal 
the estUll3tr:c.l maximum yield (If the well at the end of the I~I wa'l nol c:uel 
rUlIC was fllolled Oll!!k,' Inguithmte scale while the tlra ..... t.lowlI ....· as plulled on 
the ... ,tlmn:III': ",·ale The thH:e ~ICpS wCle pft.Ucd on the same graph paper, Wllh the 
origin nf lillie 'or a!1 "eps laken as .he beginning of the lest Values 01 s/Q were 
delemtined tor eal.h ~Icl' U~ult! In arilhmetic ~raph shect. \"alue, of slQ wcre then 
plOIIOLI "~IMl Q. ·lllC fnrnt;/I"III COrtSt:U1t IS uleulalcd rrom lhe intercept uf the li-.:: 
wilh tlte slQ axis and the well lo~~ ~Ull!ilant IS t.lctcrmincJ from the slope ur Ihe Ime 
IIffltlhrouPlbeditapoinlOxuh.I(47) 
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ntis part or the allllysis Wo\" ;lIl1leJ al relating each or (he w/ll.'t:leiJ 1100 
rtttlfiJc:u data or borehok ;u~ illluirer properlies. and IlClt<.:C 'UlIlfllanlinf.! the 
inronllallon lhal has betn amaS.!il.'tJ _ Reievant Information as well as pallerns arc fairly 
cas)' In cklc\:l when dala all: lreated slall5licO\II) Table 3 shows Ihe summary of 
IxlldllllccharacterisIICS'ludK:U . 
Borchole I"m(lcruc~ " .... 11.: (lIC!oC'IlIl:U III tlK: h'"11 ur pCn:CIII:I~Clo, an:ral!'-·~. 
(rc~u""'JI:)· uiSl.nbutions :lIkl h,.'.llIgrams. Prnpt.'llIcs such a.~ borehtlle t1eplhs. 
overburden thicknesses ..' lIulfer thicknesses, aquifer depths, yields and Sialic water 
levds have been 11resemed in tables and llgules for easy visualilatlon 
In lerl1l~ ul pcrcental!es. mlormatltm is pwvided abuul thc: frcqucncy of each 
propen) til Ihe borehole: . It th. ... refore gives 8 good irkhcallon of the relative 
prcpollllerance of cadI propcny in the ~mple . The Olean of the borehole propertlt:s 
hn tW. .: CII estimalCU. lis m,lIn Iill1l1ittinn IS that II I~ vulnerable to clCtreme vnlue'. m 
thai it may be unduly afr«lcd by very high ur very low \"alues which fo: .. lIl .... lII'Cfo:(IVcJy 
iocn:;asc or dtuca'C 11~ 1I1:1~lIllullt: . The standard dcviatiun was also u~1I as a metlivd 
(OSU01manlC thecllspcrslonpropcrt,es Inessence.lhestlndard devlauuncalculates 
the :!\ler"J!c amounl of de\llatlon from the: mean. It pt:llluts the direcl COmp<lIISOIl of 
del:''--';' uf(h"JlCrsion fur cOIl1potrable umples and measure. 
Curn:lalions .. nd regresMuns were also usccl to proville easy-tn . interpret 
indM.:ahons of the relative stlCIL~th uf the relaHunshlps hcl\1teen hurehoie propcrtie~ 
ConelalM>n entail. . the proVision or a y,mJstick whereby the mtenslly or ~trength of 
it,cI .. tlllrnh'pcanbedclttnllncd 
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Pearson's product 111"1111.:111 uf cUlfdatlull cocffiCient \\;l'i "dOpll·tI It IJo.lllh:n 
referred 10 as Pearson'5 r In this I1lCi~ure of eorreiattull. lite' nalure "I thc 
n:laIlUll'ihip hClwcc:n IWu v;IIMhic!ri I' clther :. f).lItern wluch implies a negall\'C 
.clalltlll:.hlfl. mean,"!: thaI as ~'IIC variable IIl1:rcascs. the other tlecre;,scs. III' a po~iliv(' 
relatiunslup which mearu hil!hcr values of one "amble arc: associalctl wilh higher 
values of the other 
IInwevc:r. Irnocurrel;ttiun isdiscefmblelhcll there is \'irlually no rei aliollship 
bc:lw«n tWI) variables . l'eilTsull's coefficient of correlalion (r) varies between -I anti 
+ I . The closer r is 10 I. whclllCr positive or RC!!:U!ve, the Slron~cr the relatlllmilip 
oc'"ccn Ihctwo variablc); 
RCI!I'C!rislun anal)·sl' \\ .... al\ll pcrrurmetl as a means OfC-';'P'C'MII!-! Il'lalion.'ihips 
amo~ pairs of vOinOillhlc!" 1:,1\ h 1Cl!ICSSlim cuc:fftclcnt (R), cstllllalc» 11M.' alllUU1I1 of 
ch.'n~e tMt 0l.'CUf'S in 1Iil' tlqVIIUCllt variable. Morco\'cr. the: rel!ressioll coefficient 
ClPfC'!oI.."'i ,he lmotUIl IIf ch;tJl)!~' IIIlhc dcpcnt.lent variable with the effect of all ueher 
indepcndeor.vanabln tluringdflillngtiperalions 
Cum;I,,"01l and regfl!uion analyses wcre performed fur Ihe borehole 
properties . Gculogic innuclk.'c'i un some: holeh\llc properties were eSI3hhshed rrom 
11lc!;(' ;!In.al) )'c$. . This cn.lhln Ihc signific;am relationships CAI\tlll); ~mong these 
P"."erttcSlubeuhulncdalkJ .I1'iOresults in a bellcr uoocrsl.llkhn!! IIr,heoccurreocc 
of glltUnrJw.1lcr In [he ~Iudy al~'.t 
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TABLE 3 
UOREHOI.E DEPTH 90.0 3U 10.8 
(m) 
OVERBURDEN 600 262 10.2 
rHiCKNEsS till) 
AQUIFER 3.0 18 .0 7.3 27 
THiCKNE.~S (1111 
AQUIFER DEPTH 5.5 55 .0 22.1 9 .0 
(ml 
107 0.8 21.3 8.6 4 .2 
1.1:\0'(:.1. (m) 
YIELD (Il1nin) 192 4.5 270.0 25.4 20.3 
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Bon:hok depths computed for 186 boreholes range appreciably hetween 1'2.0m 
ami 90.0 m, and this dep:nds entirely on the ctlmhination of local hydro8cological 
,,,"dilium 'iu,h a~ favourable IitlKllosy. the presence of siruciural features and the 
clttent of weathering. An averattc or 31.2 In and a !)olandard deviation 01 10.8 In was 
obtained from the 186 hQlehole~ 
About 80% of Ihe boreholes in lhe siudy area have depths hctween 20 and 50 
m. Analysis indicateslhat few hureholes were drilled deep enou!!h 10 verify Ihe full 
potential of lhe bureoole Sile'i !.C11.'t::teo. This IS ilhl\lrated in figure 7 where few of 
the wells reached depths ~n:ater than 60 III 
Avcrat!c bun:hole depths ,ue wmparable m64 !!ranitic rocks and S4 boreholes 
dulled through greemtones (Tahle 4) Thirty·fuur percent uf the boreholes were 
Intercepted In gramtes. 29'!- III ~Iccnst(lncs. whiles 16% wert' completed Ihrou~h 
phyllites and 21% drilled III Sl."lusts. Thedeepesl borehole was from n production 
oorch.,lc drilled through grccmlOne. This borehole at Saan wilh number .~99 I ; 2 has 
a final depth or 90 m and is IUC3tcdona nalland. wllCrt'asadcplhuf43 III recurded 
rrom an observalion borelk,le. was the deepe'it borehole al ValJ,(uuri with number 
431E 1 from phyllite 
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(f) 
I 
I-
fu 
0 
l1J 
~ 
0 
~ 
a:: 
g 
LL 
0 .(.\,j  
~ 
~ 
<.') 
:0;;  
i 
.,; 
i<: 
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TAIIJ.E4 
MEAN 
tm) 
11I:I'TI)(M) 
GRANITES 64 12.0 42 .0 26 .4 6 .4 
GREENSTONES 54 12 .0 90.0 28 .8 12 .2 
PHYWTES 39 240 64.0 10.3 
SCIIISTS 29 23tl 65 .0 34.6 8.7 
TOTAL WELLS 120 30.3 8 . 1 
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TAIII.E 5 
UORI:IIOI.E m !. I'TII!i(u11 
MEAN 
FLATUNO 120 90.0 30.8 11.4 
HILLSIDE 160 M .O 33.9 10.4 
VALLEY 29.2 7 . 1 
TOTAL WI'lLS 181> 900 31.6 8.8 
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Ihecharx:esofobtaimn~moocratclt'hl)!h Y K.'h.harccnllOllK:L'\IhyincreasinglhedcPlh 
o( the borehole 10 a much ~realcr eXlelll. !llnee some: localised (ractures cOnlamm~ 
..... alercould he found aldeepcrdcplhs. II was oolcd Ihat n%Oflhcborchn!c» were 
drilletlm nall;llkh, 17~ on lullsklcs and II 'J. in val1e)~ . Hllbnds and vallcy~ have 
t:Omp~rabk average horchvh.: llcplhs fTahlc 51. 1~ latlal1d5 and valleys arc t:1I11~idcll."\I 
;n r. . vuurahle areils lut deeper ruck lkcompol' ititlu alld <Ire: IIk.ely to 1.1I111t:llIc Will! 
fractured zones. However. It \Va,o; ob!lCrvaJ Ih:1I d!1l1tn~ was stopped when WaleI' 
fmm the mooerately dIXUIIlJlUo,c.'\IlO1lC' was loulfit:ICIll 1m hand pump iru;tallatiun 
The overburden thtd.ness IS the depth to fresh bedrock. A lulal uf 186 
t"II.rchulcs were analysed flIT Ilvcrhurdcn Ihit;:knco;ses. The minimum uverburden 
Ihll;kness is 9.0 m and the "'OIXIIIIUIli IS 60.0 Ill . The mean and standard deviatlun III 
the 186 borehoks are 26 .2 11\ .!IId 10.2 m respc:cll\'ely . The: natult! and distributiun 
ofoverhunJcn L1ud(nc~\CS is prcM:'ntC\J in (Figure 8) 
In onler 10 ohlam adequlte yield, it has been found thai a minimum regolilh 
thK:k.nr:ss uf approximately 10 m is required . Thlli IS m agreement Wllh a !-iurvcy 
conducted by Omorinbola (1981) over Ni~cn.UI hascmenl rockli 
Nearly all the: horchlllcs have overburden Ihicknesses exceed Ill)! 13 m . 
Banoeng-Yakubo (1989) reponed an averaae of 29 m (or overburden thkkness in the: 
twemenl rodu or the: tipper Rc~iuns of Ghana Ih~11 include the study area Sueli wilh 
Ihll,:~er oY'erburdcn ~crc PII"lIlIc, 10 dnllinp: ror waler in the study area. since the 
fm'u,,"lthc: dflllin~ ptVJ!r.tmllll· \\.1, based mainly on (arpin, water from Ihe: K'l!ulith 
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Overburdan Thlckneu(m) 
f1G.8 HISTOGRAM Of OVERBURDEN THICKNESSES 
66 
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"v~r;t~e overbur~n thtcknC's5ei are comparable in granHes and grcellStu"e~ 
,Tilbk 6). However (he (hickesl uvcrhurdcn of 60 m was obtained frum phyllites in 
GuorpUtl and Birilu Wllh bvh:hHle number 399C 10 and 437H 1t'11T5pt\:11\c!Y. bolh 
of which 1ft production boreholes . Thirty boreholes otliled thwu¥h phyllllcs llave all 
average ovcrbunkn Ih"kn('\\ ur 29.9 m, while an ;nernge of 30.S 111 \\:1" ~lht;lincd 
from tlllny·eight boreholcs..:umpleted inS4.:hi!>1 fU..:ks 
rhc rclalivedcpth;uKldc:grccurwealhering ina rock dcpentls 10 SUIllC eXlc III 
unlhe IIIlensity of frnclurjll~ ;uk.! the grain size of Ihe minerals IIIlhc I"I...,;k 
Chillon and FOSler (1993) explained the importance of the regolith Ihickncs~ on Ihe 
success rile of dulling. 11M: Jl!golilh (hl(:kncli~ provides the dununant element.s of 
aquifer "orale 100 lklermitk! the available drawdown 10 the most protJuclive aquifer 
horizon 
Overburdcn Ihllk •. e\\C' cIlI,.lltllllclI.:J .n 1l4illands were III¥hcr compared lu 
Ihll~ tourkl in valleys and 1111 IlIlIsMJc:s. An avcra¥c tlf 2U.6 11\ o\'crburdcn thkknc~. . 
was obl.llllcd (rom 32 bureholes drilled 011 lullsldes, \\llIle I.:olllp:uahic avcra~cs of 
H .6 m and 25.1 m were \llliamcd from 138 boreholes drilled in lIatlands and 22 
borcholesdrillcd invaUcys IcsjlCI:tivcly crable 7, 
Uorehules drilled ill n"llands Ind valleys ha\c thICker ~aluralcd regoliths Ilk.! 
hence represent ltmes uf deeper weathtrin~_ III IIlllst I.:a~~. weathering is less deep 
in Il:$s resistant Itx:b 1111 11111 tllPS, while in \'alle~·s and natlaoos. wealhrrinlt IS 
mtcllSl\'can..lda:pef 
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TABLE 6 S.l~IMARY OF OVERBURDEN TBKKI"ESSES 
M:I.:QI<IJI~G_:nj~ 
Gnmiles 64 J75 5.9 
Gr~nslones 54 12 .0 2ll 8.l 
Phyllites 30 
St.:hists 29.9 8.6 
lO S 1M 
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TABLE 7 
Flalland 132 9.0 60.0 25.6 10.2 
12 152 20.6 10.7 
Valley -130 25. 1 7.8 
TotllWelis 23 .3 8.6 
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Aquifer thktlk:"l'\ \'ary between 3.0 m and 18.0 m in Ihe 192 horcholes. 
The mean is 73 m ancJ Ihe MandaN deviation is 2.7 m ,\htlUI ~71j. til aquifers in the 
siudy area have 1Iw.:knes5CS Ic~s than 10 m. A distrlhutlon of these resulls is prc~n1cd 
in Figure 9. 
Aquifers encuunlcreti in phyllites and f:reell.~IUf)t!!i ilre thickerlh;lIIlhuSt: found 
in granitcs and r.chists. Avcra~l' aquifer Ihktncs5es in the phyllitcs and ~n:cnSI(lnC,. 
are 8.1 In and 72 III respectively. Average aquifer Ihickne!Osc.5 ;ne hnwto"ver . 
ctllllpamhie III grecnstonrs :Ilk.! st:hists (Table 8) . 
Aqulfcr.; ue genera II )" di~onllnuous ;lrk.! vlry from I few meters to lens of 
tIICIC,,,!IHCk. Thick aquifers are found inlhephyllilesduelolheprc!.Cnceorfraetured 
quar!z \CIII~ in Ihe moderalcly dl,."\:omposcd lones of dK':sc HICk .. 
Aquifcr~ III gn:cll\ltllll'''' .lIl' al .. n lililk probably because Oflhc dcvclupL'I.ljoim 
1!yslcm~ which corutllull' 1'1"~lll"t.:IIVC hi,h-yieldintz "'-Iulfers. In the granill'" :'md 
schists, ..... hcrcquuuancJrci!malllc\"emsinlrudetherocks, well·developed hac!url'$ 
and joints !hal tarry appn:u;lhk amounts of gmuncJw;1Ilcr occur. Rocks in whieh these 
structures (lccur decornpu~ lI)ore readily and ,U0I1111IC the devclopmem or Ihicker 
aquifers thanthu<;c whi..:hi..lu f)otcontain these .. U1J\,.lutes . 
Avcra~e l\lUircr tlut:kncss.cs are cornp<uablc rn nall .. nd~ ark.! on lullsKies. TIle 
thickest aquifer of 18 m was uhtalned from a production borrhole found in I nalilnd 
011 Tanchara in the Lawra i..Ii~tllll '" Ilh tJ.lrchulc number 43711 7 
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9 I. 
Aquifer TtllckMn (m) 
FIG. 9 HISTOGRAM OF AQUIFER THICKNESSES 
71 
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TAIlI.ES Sl.!MI\f,)RY~ ox AQ!;lf:f;IIJIfICKN[~SJ~ 
A~T()IU"!'I(; I9~ 
AIJI 'IH:K THlnINL~SI ', S (nil 
Granites 123 6~9 2.) 
Grccnstunc~ 56 H 17.0 7 ~ 2 2 ~ 9 
Phyllites )0 IS .O S.) ) .1 
15.0 7. 1 2.6 
TOIalWe'ls 192 18.0 2.5 
72 
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Vallcysand nallandsare knllwnlU t'C OIs\Ocjaled with (racturrsanll 1:11111.:' Itt 
deeper decomposition. How\:\'c •. 23 borehoh:s drilled In valleys have a mUlIllIUIII 
aquifer Um:krk."SS of 3.0 m llnd.1 1IIi1.\lIIIUm thickness of 12 m (Table 9). It has been 
IlOlil:ed that more boreholes werc dnlkd III Oatlaoos than in valleys in lhe slully arca. 
This is hccausc:. mOM ofthc valleys are liable to l100ding 
Aquifer deplh is [he l.kplh Itl top of the productIve water he.1nIl~ tunc: 
Approximately 50S of tile aqUifers have depths of less Ihan 20 m. Figure 10 
illustrates the nature anLI disUlbulion o(aquifer depths in 192 boreholes 
Aqulrer depths range considerallly from ~ 5 m 10 55.0 m and average 22.1 In 
with. sllndard deviation of 9.0 nt. The least aquifer depth of 5.5 m was obtained in 
a prol.1uclion borehole loealaJ un a OalianLI undcll .• in b)' granite. This shallow aquifer 
iuluetulhep.cscoceofalhlllaoopuorl)·de\·dopcd\\C3Iherwzone.llowcverwater 
was flOl encountered at such shallow depths in any of the observalion boreholes. 
Average aquifer deplhs IIf 18.2 m and 18.9 m an: comparable in ~ranilH and 
grccmlOnc:s rnpec;livcly. Howcver. the phyllilcs and schisl.~ have the 5amc maximum 
aquifer depths of 55 m in the study arca. The deplh to lOp of the productive water 
bearing I,one in borehole number 4.17£ 33 al Lawra was the hi~hcsl due to the 
presence of pqmalilCS. quanz veins and fracture o('ICmngs 'SIOI.:iatec..l with Ihe 
underlying weathered SlChl~l. Htc preSCI1l:C uf Ihe~ ~c:()logical structures provide 
;nelluc~ furdttp .... eJ.lilering. thkkeraquiferdeplhsand increased yields when they 
an: lound Within Ihe wealhered zone and underlYing hcdrock. lbe summal) III aqUifer 
tk(l4h.'i ac.:.:ording togeolo!!y is Uwwn in (Table 10) 
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TADI.E9 
Ak<.:Q.~!>ING TO TOP<X;RAI'IIY 
.'VI "1'1 K I!IIC""" s~, ~ I.U) 
WELlS ~; 
Flalland 138 3.0 18.0 7.4 2.9 
llillstde 31 3.0 123 7.1 2.3 
V.11ey 2) 3.0 12.0 6.6 2.2 
Toeal wells 3.0 7.0 2.6 
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Aqu i fer Dep t h { m J 
fIG . IO HISTOGRAM Of AQUifER DEPTHS 
7 5 
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~il.1.M.HAI(Y OF AOUFER O":"~JIs.. 
AQUifER DEPTIIStm) 
Granites 5 5 33.0 18.2 5.6 
Grccn.';Olones 56 41.0 18.9 
Phylilies 150 55.0 31.5 98 
55.0 259 
flliaiWell5 192 550 246 
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Generally, aquifers are elk:Ounlered al shallow depths in valleys and flallanc.ls 
than un hillsides. Average aquifer llepths arc: comparable in nallaoos and valleys wilh 
values of 21.4 mand 21.2 III rC'ipt\:tively (Table II). 
5.5 DQIU:I IOIJLYJ Ej.!1S 
Uorehulc ~ leld analysis shows thai variatiollS in yielll wilhin Ihe study area are 
large. The lC'00e1M:)' j'(l( must yM:lds 10 be low is vcr)' i!reat willi only a limited 
number of high Yleills 
Esli,runed yields oblained from lhe drillers log generally fall t'lelween 4.5 
I/min. and 270 Ifmin. in ,92 borehoh=s. The mean and standard deviation is 25.4 
I/min. and 20.3 Jlmin, rc~pC(;tivcly. The values of the mean.nd sta,Klarll de"iation 
arc clO5C because of the ex((cme variatioll5 in the yields as a resull ot the 
hclewJ!!cncous nalureofaqUircrs in the area 
Approximately ci,hty-fivc pcrt:CIII or boreholes yield 30 IImin. or less of 
water . Figure 11 illustrates the di\ulbution ofboreilOle Yie ld» in the study area. TIle 
distribution is heavily skewcd to the lefl due 10 majority of the: boreholes exhibiting 
Inw yields with values less than 301/min. 
Av\.'ra)!c yiekbi in ,r.mite\ and greenstones arc comparable . TIk:: mean yield 
for sixty-six borchoa in grilllltc~ I~ 22_8 Ilmin and the average yield lor firt)'-~ix 
gn:ellSlone rocks is 23.S IIl11m (rahle 12) 'Illc 11I~hcsl yielcliof 1351/min. in lhe 
gramles and 148.5 ltrnlll III lhe glccmlont:s obtained from boreholes 438G 03 in 
Jintpa-Yiplla ;and 437E 13 in uwra arc monltonng bon:holes in the region. 
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TAUL~ II SJ.!I!1~1~1!1. Qt~!L\JJF~KJ!E.ITII~ 
t\.C.J.:QJlll.!!;JLllLH).l'llli!!AW.Y 
AIJ"U·I;RDI;PIIISlnli 
Flatland 131 5.5 55 .0 21.4 8.8 
Hillside 32 55.0 25 .1 10.6 
Valley 23 35 .0 21.2 5.6 
TOf.IWclis 192 5.5 55.0 22.8 16 
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Ul 
Cl 
..J 
W 
;: 
W 
0 
1: 
It: Ol 
0 
eD t-
::; 
~ 
I I 
i 
.,; 
;;: 
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Tile yield from Ihe<;e hureholes are III~h pouibly because or tilt rlUlltcmu" 
fraclull..'d quartz vein.. . anti t.:lushed zones kk,:ated within the decumpo~ed zone~ of loc 
profile Thest ~trut.:IU'c~ offcr areas of high pcnne.,l'tilll~ wilh n:larh'cfy high ~lora~e 
capac rill''' tn lhe walerhearill!! zones 
In 'Ollie cases. llluderalC to high yields are 3s'iOCialOO with ~r.lllitl''' bcCilUSC 
JmlllS are t.:reatc:d hy colIIl"at;tioll durini! coolin,. A typicill example is. at 1"\llm", inlhc 
Tumu !.listric! with borehule lIuml1C"r 444F 2 (monitoring hurdwh:) which Il.1s a yield 
of 103.5 Ilmin In cOnlra~1. till" 10\\ yrchJing wells are open 10 only a few Iractures 
Ihalimerse((lhewnlhercd.wlll' 
Thl" lIIean y;cld til 2~ horehoks louled In \'allqs IS 17 .. IlIlIill. and the 
avenge yiek! OOtline.J for DK lJom:holcs sited 10 nallarll.h IS 28.1 1/111111 . An avcrage 
Yield of 20.2 IImin . WIS uh'''lIICU 1m 32 hmeholes located on hillSides Crable 13) 
In (he study area. ll"sldcnlS rely tN.;nly 011 grountlw:uer for their walcr 
suppltes lJurinillheprojcct intlk" IQ70·,. horeholcs wcre usually required close to 
the comrnunitK's which in somc I:a~!> ~verely constrained the I::hoicc o( sites for 
drilhn, . Most of Ihese !otlCS cluse to the communities were not quite pronllsill~ but 
had 10 he compleled. hcnl:t: Ihe low yields 
Ahou! 70% "r tlk" .lIca .. tudicd i .. underlain hy ~I.mue~ . These rocks arc 
generally COI1$M,k,ed 10 hi.: pUHf aquifers excq>l when Ihey are associated wilh (hick. 
deep weatherrd ZURC$ resoltll1!! hom fractures and joinl.\. quanz Ind pegmatite" vein 
Intrusions as 'Nell as frKlu,'e.\ and Joints in the frC'.\h ruck!; 'll'1e presence of these 
suucturesUJUallyincreaSClhc)lCkisofbordk>lcssignlficantly 
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Uoreholes drilled thruul:!h ,ranites have toc least average yteld. while 
boreholes drilled through schists gave the highest average yield of 33.3 Ilmin 
Granites" reenstufles,phyllitcsandschistsinlhesrudyareahaveproduced Jess wat er 
(rOIl1 thcir dccompo.!>C\l lOUCll. 1I0WC\·Cr. where thc:-c rocks are fractured or intruded 
by quartz and pe~rmtit...: veins. relatively high yields are obtained ThiS cxplall1s the 
hi,hest ilvc:rage ylt'ldsohl;UIIC.'(j lrom hureholes cumpfetetlll1 ~llI !ot, 
TopographK: inlluclk:cs on hurchulc y lcld~ arc "cry ' 1,!: llIlu:31l1. In the study 
arcO!. horchole .. hJCOIlcd III lIalland~ and valley!! cmnmonly yield more waleI' IIUln 
boreholes sited on hilly upland areas ur un hillsides . However. a monilorint! borehole 
H8C OJ which is artesian (flowing well) was obllintd 011 a hillside at Gurungu . II 
is situateti near the fOOC of a relatively Sleep slope with .. warms of quartz and 
pegmatite veins in tbe dttomposcd zone i1S indicated in the drillers' log . Thl .. 
untlerly.n!! weathered rock can form a 5uh"tanlial groundwater reservoir and may be 
receiving .M1Ilk" water rrumlracturcs III tlk" bedrock. (hereby enhancing the yield in 
Ihca14UI(cr 
The high yteldmg wells ar!:open 10 raunerous (ractures lhalare found wilhin 
the weathered WIleS beluw the WOller bearing zone in natlaoos and valleys. However. 
most of these boreholes can no lonaer provide enough water for lhe growing 
populalion in the regiun a' demand increases put prtS!ure on the ~flIundwillcr 
resources of the area. 
Parry et II (1987) reported that the boreholes Ire yielding less waler and are 
nllt able 10 provtde a continuous supply of WOller. He further di!\oCusJ;e"-' Ihat the 
bun::holcscanno loni!l'I lIU).lam the discharge capacity of the pumps used during the 
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Graniles 66 45 1350 20.3 
Grcen.o;lones 56 1485 235 21.5 
Phylliles 4.5 2700 26 I 19.6 
Schists .'\04 
TulalWelis 45 270 Il 27.4 22.8 
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Flatl .. nd 138 2700 lK 1 24 .8 
J2 '10.0 10.0 
Valley 22 "g 
TOlalWc:lIs 192 208 .2 IS .8 12.4 
84 
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III ilny ..:a5l:. IlIOSI uf IIIOoC htm:hoks arc ~ing reUe\·c!np.:u and relklhlill"h.:J 
In d laf~e extem. New Villill-!c Level Operatiun 3nd Maimenance tVLOM) pumps 
'111.11 '" lhe AtmJev and Nira pumrs arc alsn ~ini! installed to replace Ihe old MO},lIti 
.1uJ Mt.nan:hpumps 
Slatu.: walcr level, IIICOI'U1t'lfdurllll! pump illst:lllalions in 107 buft:htllcs vllry 
fWIII U K 111 IU 21.3 III belO\~ IZIUUml level with an average of 8.6 111 and a sialidaro 
deviation of 4.2 III 
Aboul 82~ of the boreho~ have stalic waler levels not ex.ceeding 10 m 
(Fi,ure 12). The efred of geology on static waler IC\'d s IS shown in (Table 14) 
Ooreholes drillnl in If1Inile have Ihe least 3\'erage s talk' waler levels. Those drilled 
III ~rCCnslUnto; and phyllites IliIve: (.:umplrlible a\'era~e stalir.: Wiler levels . 
Comp3rablc avcrilge Miltl\.' water levels wen: noticed (rom 70 horeholcs drilled. 
in niltlands and 12 borehole, dnllc.J in v;Jllc~)o TIM.' ,I\'eragcs arc 8 .8 m and 8 .7 III 
respectively U Ihuwn III Tallie I ~ 
Evidence 10 support the: !'elZi,'u;11 Jcclinc uf y,aler levels in lhe study an:acan 
be shewn from the compari\4111 uf \Iall\; waler level .. measured dUfln~ Ihe study (rom 
lOS bnreholcs and loc)lalll: walcrlevelsobtainr:d from the salllc horehules a (the lime 
ofcunslrucltun. Table 16eivesana\'crageofR 6m for the oneinal sialic walerlcvcl!li 
retuNed al the: time uf CORStrucliun and an ncrai!1..' of 10.9 m from the: sIalic;; Wiler 
levels measured during Ihis siudy . In addllion, an a\Cr,l~c dcdillC 01 MalK: waler 
levels in 76 ttorchoks was 4. I m and an Iven~e me: uf \(allt: waler levell in 29 
bon:hulcsWilS 2.5 m 
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Static Water Level (m) 
f1G. 12 HISTOGRAM OF STATIC WATER LEVELS 
86 
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STATIC WATER tEVEl CIIlI 
GraniltS 51 17.4 3.7 
Gretnstone~ 26 0.8 14.3 8.7 3.8 
Phyllitcs 1.3 15 .6 8.5 4. 1 
SchiJU 3. 1 21.3 10.9 5.3 
TotalWtlls 107 0.8 21.3 4.2 
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TABLE IS ~~J~JU;t:ATlC II'Al]l~_L!lJ%.LJ! 
~n'J)RDlNGJ9_ _n !f<lli!!APIIY 
~IATI(, WA1ER I.IXU.S (1111 
Flatland 70 0.8 17.4 8.8 
Hillside 25 1.2 2\.J 7.8 4.1 
Valley 12 7.0 8.7 5.1 
Total Well!: 107 0.8 2\.J 7.9 4.6 
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STAnc WATER LEVELS RECORDED DURING STUDY 
ORIGINAL CURRENT YEAR STATIC WATER 
SWllml SWLlml LEVEL DIFFERENCE (nll 
H IMPLIES THAT STATIC WATER lEVEL HAS DECLINED 
l'jIMPLlES THAT STATIC WATER lEVEL HAS RISEN 
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BOREHOLE ORKUNAL CURRENT STATIC WATER 
NUMBER SWlfm) SWL(m) lEVEL DIFFERENCE 1m) 
-~--
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BOREHOLE ORIa.NAL CURRENT STATIC WATER 
NUMBER SWl(ml Swtlml LEVEL DIFFERENCE 1m' 
" '''' ..~  
--'i.1_ _ '~ ~ .. ')11 __ 
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ORWINAL CURRENT STATIC WATER 
SWL(m) SWL(m) LEVEL DIFFERENCE em, 
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()\cr .. 10·ycarpcrlo", .•r oUI72~orlhebt,J"('holesinthere,i(lI1havec.Jeclined 
In thclr waler leveb considerably. whilu 28" hIVe risen in Slatic water le\·els . The 
only tlowin, lIrtc,;an well seen during the !'Iudy was found at Guruugu ;n the W .. 
!listricl. 
Bannerman (1~90) reported Ih.lthe area IS ;t waler·deficlt region .lnd lIormally 
c~rcllenl.:e:s.dry seasunol sil( l1Ionlhsdunuion . Sometimes. Ihis period is exceeded 
31kJ Jcadslulhe!lry;ngupoflllany water bodies Moreuver. it W3!1: observetl during 
fhe J;ludy Ihal in low rainfall months. lhe ,"hah,lanls depend mainly on Ihe bnrtholes 
tllr II'!CI! wOller supply which in most Cisn cannot pru\'ule enoulZh water for the 
population. 11lis IS enleoccli in lhe reduced yield of some orlhe boJ"('hnles in the 
Uppcr West region which can be related to. signific3ntdec1inc in waler levels. 
Puuible causes or lhedecline ,an be llI1jhuled lu redu,etJ recharge. low minfaU. 
IItcfeased surfac(, run-orr an'" e"'(').\i\'e wilhdrawal of waler (rom the boreholes 
DaLa obtau-.oJ aull .1~lysed serve to ~how Ihe ..:ydk ItU~:IU;llltlllS ill 
~r"undw~ler leyels and its dependence on Ihe rainfall regimc. CUllIinuous 
mc,,'u~ments uf ~ralll: waler Icw:1s in five rnonilOtmg bo~holes from AUlu~t 1993 
10 August 1994 foronr ye;!r looll:atcsthallhec)'cleorri5eo(groundwalcr levels in 
ther.lIny~)ns;tntJdel."hncinlhedr)'seasons~nntinue5.ind('pendenlorrespOfl.'iCS 
luluc:alpumpmJ! 
The hydroJ!:r3ph tlr monilvring boreholc numher .'98C I (Figure 13) ~hows a 
steady decline In waler levels in dry momhs and the rI$C ul waler Ic"els in r;uny 
93 
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L.argewillerlevell1uctuatlunsart:alsocausedbyncarbygr""'IlI.I~·3tcrpul1lpinJ 
and Ii) W~ extent cawed by horehole dogi!mg thus leadlll~ to turbulent now 
proceut~ whICh a~ iI consequence reduce the effICiency of the boreholes. 
The sc:aWllal trend Wil~ caused mainly by grealer wllhdraWl1 of I!rouoowater 
during Ihe drier months. 'nw; average static waler Ie\'el uhtamc:d within the year lor 
Ihi~ borehole is It 1 III helow grountJ level 
Figure$. 14.15.16 and 17 show hydrotlrnphs of munitoring borcholc!i 40lA 7. 
4UIG 6. 4001> 4 and 4030 I re~pec:lively which ;tlso indicate lIuctualioll~ rehtled 10 
seasunal changes in pumpage. Average slatic Wiler levels recorded below ground 
level in each borchok: is 4.2 m. 9.7 m. 26.0 m and 19.8 m respectively. The waler 
level fluctuallons In horehlJlc~ 40lG b and 4030 I which oblam waler from the 
motkralely decomp())td ZOIlU in l!ranile5 is higher Ihin Ihal found in borc:holes 401 A 
7 lOLl 4000 4 which wt'rc sc;tct:Ik.'\J 111 Hiritnian ~lmlS Generally.lhe: 1>h:1I1' ch:Ulgcs 
inlhe water ~velllil'flltneO()rthl.llcscanbc IlIriholed lolhc 1II1t111.llmgcap;tctlyor 
lhe !<ooil dUI1I1~ lamlall. tlK' soil mOI~luu: dcllcil and (he permeability of lhe rocks. 
However. the waler k'\c! Irend~ are ~lmjlar wilh a gradual rise in watcr levels during 
the ramy sca~nanda stcady dcclinc ofwaler levels in the dry scasun 
Thc:seob5c ...... ali,,'" cltiliain dearly Ihal faClors which are likely (() inl1uefl(c 
gmunl.hulcr levels 'n the 1('~llIn arc related to The hydrol(J~y of the area especially 
evapotr.ln!opU3110n alllJ Ihl: 1.111; of redl;Jr~c Rt\:h.u~c dcpcl'ld~ 1m the rainlall 
inlcluilY· tllslul:lulltm. the anlUUnl uf run·oH alll.l Ihe nalure of the stili surface . In 
~crcral. (funfal) IS low in the arta and ilS annual distnl'liJllun is very poor. 
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AuO Sept Oct Nov OtC 1 Jon Ftb Mo,. Apt. May Jun. Jul Auo 
1993 I 1994 
FIG. 13 WATER LEVEL HYDROGRAPH FOR BOREHOLE 
NUMBER 398 COl - KALEO 
95 
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AUG Sept Oct No ... OtC Jon Feb Mor Apr Moy Jun Jul AUG 
1993 I 1994 
FIG. 14 WATER LEVEL HYDROGRAPH FOR OBSERVATION 
BOREHOLE NUMBER 401 A-7 - JANG 
96 
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June Jut AuO Sept OCI No ... O.C ' I Jon. Feb Mer. Apr Moy June 
1993 I 1994 TIME 
FIG . I!S WATER LEVEL HYOROGRAPH FOR BOREHOLE 
NUMBER 401 G 06-WA SOUTH WELL FIELDS 
97 
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AUQ. Sept OCT NOIt. Oec I Jon Feb Mor. Apr Moy Jun. July 
1993 I TIME 1994 
FIG . 16 WATER LEVH HYOROGRAPH FOR BOREHOLE 
NUMBER 400 004 - IZIIRI 
98 
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I • • /\ 
u 
I, I ! I ! 
AUQ Sfpl QCI No ... Dee I Jon feb. Mar. Apr. Moy Jun. Jul 4uO . 
1993 I 1994 
FIG.17 WATER LEVEL HYOROGRAPH FOR BOREHOLE 
NUMBER 403 01- FIAN 
99 
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Seasonalchangesinthewaterlevelscanalsobe~latedtoseasonaJchangesinlheuse 
of water by vegetation and the ralc of soil moislure evaporation 
FiBure 18 illuslnltcs (he rclallam of temperature with rainfall for four 
\.:ol1SC(:ulive ytars in the regIon . High (emperatures are usually associated with dry 
periods when there is virtually litHe or 00 rainfall. whereas low Icmperatun:s are 
ex.pertcnced III rainy pemxh Uunnf: the rainless monlhs, temperalUres are very high. 
Yaulachock (991) dlscLWoed thaI waler Icvel fluclu.niuns nre caused by 
\,;III;tIIOns in recharge, water usc and evapotranspiration. The :nJvcrsc ellet:l.s uf 
relalively low or falling 1!roundwaler levels lead 10 desertification which in all 
prtm...bilily Will eventually include a reduction in recbargc _ Gombar and Kcnl (1987) 
reported thaI the rales ofrechar~e and recharge volumes can be calculated by long 
tem mea$urtmenlS of waler levels in borchulc~ 
Afunhcr indicalion of watcr level declines tnlhcregioncanbeClbscrvcd from 
FI~ure 19 which shows the Malk:: water le\'c,," recorded from nine monitoring 
boreholes al (he time of comlNeliun and that uf ~Iatlt: waler levels recorded al lime 
of study in the wnc boreholes al wme communities. Ex.cept in Gurung:u. where (he 
borehole il nowing. there is an appreciable decline inthellatic waler Icvelsorllll~1 
boreholes 
MurrQver. cnvlronmenlll ciql:radnllml has serious con5C'IuencC:I on (he 
.... c~eI3Iion and wbeo it r.un~. lhcrc IS Ju~1 lillie infillratjon into lhc 5Oil. In addllion. 
thcsun·IUl&Cnsi,ylshlghand~kesthesollsurfacc"ndpreVCnls.theea.syinfillration 
or water mlo lhe soil and also hinders. sub~qut.:l1t pcrt.:ulalion into the M;wundwJler 
circulation sy5lctn WhKh c:oruributes to ha!iC fl,.\'\' 
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5 7 ~TIQJ"-DETWEE!,; DOIlEIIOLE~ 
The present study lndlcales lhal lhere exists some relationships between well 
propel1ies in the boreholes Table 17 compares well yield wilh oiller borehole 
properties such as overbunkn thickneu. borehole depth. a~uirer dc:plh. aquifer 
thkknessanLI staiN: waler levels 
Acros~ the .illMIy area. it is clear Ulal there I~ a slgmficant rd:uillllship IlCtween 
overburden IhH.:lmcssc~ and yields AhelUl rulle'ly pert:ent of Ihe: horeholeli have 
overburden thicknesses excee"hn~ 15 In with yields of nol less than 10 I/min . II is 
(toled thai overburden thicknesses in (he boreholes encountered in glanilcs and 
gn:CIISIUI1C'S have comparable mean lhicknesses or 21 I m and 23.3 m respectively 
Boreholes drilled in tloulands. are usually associaled wilh thicker overburden 
The currelalloll cuefflcient hrlwel:n aqUifer depths and borehole deplhs is 0.66. 
nlJ~ nxJicalc\ a lau IciallullshlP 01 aquih:r depthS with horeholc depths. This is 
hnausc deeper ht"cllllk~ \\crc dlliled when water bearmg zones were not imerccptoo 
at shalluwer depths Mon:u\'cr. deeper wells were drillt:d where waler was obLaincd 
rromsuchdeepdepths 
The stltK: wain Ic .. t'ls and yields In boreholes correlate Significantly in the 
study area_ The higher the YICkJ of a well. the shallower lhe stalk \\ aler Ine!. This 
isbetausc, faclorstbitcallSC increased yield suchu lhe IitholOJ.yurlhcarca. the 
topographICal \!:fling and the ~Irucillral geology or the: area, also C.!USC''' slatic wafer 
leyelsln lit;.(' mawell. 
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TABl.E 17 RES1 1( IS OF Pf.ARSON'S CORREI ATION 
80IU:1I0U: I'ROI''':RTI.:S CORRELATED CO}·:J<FlCIl!;NT OF 
a Ovcroonknlhkknessandytcld 0.68 
b BorthoJe Depchlnd Yield 
c Aquifer Orplh .nd Borehok Depth 0.66 
d Yteld.ndAquifcrDepth 0.16 
e Aquifer Dcplh and Aquifer Thickness 012 
f. Overburden Thickness 100 Aquifer Depth 0.78 
& OverbunJen ThK:kncss.nd Oorehole Depth 0.4J 
h Yicll.landSulicW.lerLcvel 0 .S5 
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'Ibere is no dircc( rdatlonslup bctw«n well yields ."'" rorcho&e deplhs. 
However. in some cases. variations in well yields are atlnhulcd 10 increases in 
borehole depth. Whateverthehydrogeologiccondilionsandlopographiclocalions.lhe 
t:hOl'k.:C~ ofoot:lulIn, mutJclalC' }lClds arc enhafk:I.'\J h)' ilk:reasing Ihe lIcplh tua l1lu..:h 
gre8lercextenllhanexpa:loo 
Data uhlaulC(.! frum burchuJc\ \\CIC .. hu wbJa:II.-.J to regressltlu itllOllplS From 
Table 18. a mullipk: rCI!,cs~iun till yield With uverburden thickncs'i. and a~uifer dCplh 
gave a \";lluC' or 0 .33 arkl 0 35 bum these results. II I~ ob,'itlu!'o tll:l( Ihe uverburden 
thickness and aquifer depth have marked errccl on borehole yields. The ytcld ohlained 
from a well depends on the rracturing and weathering characteristics of the rock type . 
Furtheranal),sis indicated an Increase in yield by O. ISI/mln for every unit me in 
sUilicwaterlevel. 
Tables 19 am 20 show the innueoce 01' a~uirer depth. a~uifer thicknes!o. 
(In:rhurdcll Ihickne5s and slat 11.: waeer levels on the yields oblained frnml!ranilcsand 
grccII\lIl1l1t' rlCkaquifersrrspeclivcly . 1I ise\'ident Ihalyields:lre increased 
respectively by 0.55 IImin . 0.62 IImin .. 0.63 I/mln . and 0.71 I/min. with a unit 
iOCn:.1SC in aquirer depth. static water Ic\'cl. overburden Ihickness alkl aquifer 
thicknes.s inthcgranites.lnfhc !!:recosIoOC's.lheyield increases by 2 19l1min. bya 
unil increase In a~ulfer thtcknns Thickcr aquifers usually yield more wafer . This 
is so bccause of.he numerous Iraclures and quartz veins present in these rocks I. ... t 
result mdeeper weathering 
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fA/lLE IS MJ,JI ; IJI'LE KH';RES~IO:>l~~;:;IJ,J1i!\lli 
D,<J'!·: NUE!\i'l' VAIUABI .l!: IS 'I liE YIELD 
REGRESSION 
COEFFICIF.NT 
~'_ __Aq~ ul_kr_~~·p_'h ________- +_ ___ ~O~.3~5 ___ 
h Aquifer Th"kn('~~ 0 . It 
L" OvcrbunJen 'l'illdlk.'\\ 0.)3 
d SialIC W~tcr Level 0. 15 
e IklfChok Otpth 0 .34 
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REGRESSION ANAl YSIS FOR BOREHOLES IN GRANITES 
VARIABLE REGRESSION 
COEFFICIENT 
a. Aquifer Depth 0.55 
b StallC Water Levet 062 
c. Overburden ThK:kness 0.63 
d. Aquifer Thickness 0.71 
107 
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TABLE 20: ~EGRESSIONANALYSISFOR BOREHOLES IN GREENSTONES 
VARIABLE REGRESSION COEFICCIENT 
a Aquifer Oepth 075 
b Static Water level 0.76 
c. Overburden Tho.ness 0.57 
d. Aquifer Thickness 2.19 
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TABLE 21: REGRESSION ANAlYSIS FQR eOREHOlESIN PHYLLITES 
VARIABLE REGRESSION COEFFICIENT 
a Aquder Oeplh 937 
b Overburden ThICkness 250 
c Aquifer Thickness 4 BB 
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TABLE 22: REGRESZIONANAlY~SFOR BOREHOLES IN SCHISTS 
VARIABLE 
a Aquifer Depth 
b. Aquifer ThICkness 
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~ 
r"hlc 21 ~hows Ihal iI UIIII uw.:rcase in aquifer depth ...q ulfer Iluckne~s ;md 
1)V\!lhurdcn Ihickness incrca:ICS Ihe yield in boreholes drilled Ihrough ph),lIilCS b)' 9.37 
1/111111 . 4.88 IImin ,nd 2.51 IImin The: same conc1ilions occur in the schists. where 
a un II increase in aquifer depCh and aquifer IhlCkne~s gl ... e~ an increase in yield by 1.5 
11mln_ and 7.4l/min. re~pecllvely (Table 22). 
Norgbe (1994) dl~u~'it.'l! 'hat Ihe llL~h ulI,:rcase in YlchJ IS possible in the 
sc;hiSl'i hcuu~. IhouF-II the micaceous and feld~palhic schislS decompose 10 clays and 
permeabililyisn:tJut:etIapprttjahly,lheschislshlllvingmarketJschiSlositiescouplcd 
with the prt~ncc of quartz veins and fl"lClUI'n F.IVC risc 10 ~rous wCrlthellnJ! 
prooucts whit: h .. ids In groundwater storage_ Relatively high yields have been obtained 
fromlbemoderatelylk\:umJ'(I~LOneslllquartz·rK:hschists 
Arels in Naooum. La ..... , ... Kalsar .. and Kuu oblain sign ificant supplies of water 
(rom schists The phyllite,. ~ive rise 10 .. n argilhK(,tlUli soil upon wc:nhcring and 
actuallye.,;ercise slfong coni lUI un Iroundw31crnlll\"elllenL by re3sonoflhl!Ir lack or 
joinlll1g Iluwever, .rlhe rock is Yl\.'wnwilh fra(turetJ quaru Ycills then relatively 
model.lle 10 hl{th yield, ;111.' ohtaltlCJ Irom phyllites 
Tillie J ... wdo ..... n pltltll Jemcd (rom pumplllg leSIS are tll"Cessary in the 
pmhClion 1)( ruture ....· iller level ch.an~es thlt reflect l0nt-1enn effccts or c:onllition.\ al 
Ihc <lquifer I10ulkJaries 
rhcre was no( enou~h J:lIa ;.I\·allahlc for the Jelerll1in.IIIt.1t IIf aquifer 
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lIowever. values COmpUIl.'\J lor Iransmis .. ,\·IIY u.\JIIg Coopcr-Jacob(l946) stlluliull 
technique ran~e from 1.210 108.2 m:/\Iay in 47 boreholes (Table 23) . The average 
uarl'nH~!uvily value is 35 2 1Il:/day and the sund.ud deviatiun is 30.1 m1/\Iay . 
The closeness uf thc qanJarJ deviation "alue Itl the average 'alue indicates 
the wkle vatlations and cXlltmity in transmis.\JVlly values of thc lla!OClllcnt rock 
;UIUlfcr~ in the Uppc(·West rCJ:lun. Oanucng- Yakubo (1989) oblnincd tnU1!IIII~(i"ily 
\-;,Iu\:'I;!nt!lIl~frullll I h,\lX3111:/lIa)· Ullheh"~lIlentl.:\lInplex r."hoflhellpper 
ICJ!.IUf15 uf Ghitna and ;HI ilverale or 22.2 m:/dly for 52 wells . 'nw:se values were 
cumputc:d using the Cooper·Jacob (1946) method , 
It is v.-urth mcnliomnf: "'011 transmisslvilies l.:omputeJ for the study were 
uhcallJed from pump tests cunducted for only one hour. According 10 Gtemaen 
(19R91 . several aquifer par.lmeten determined from li-hon term pump tests do not 
reprc-.cnl .ldU,11 v,tIUe' "Io \lIIlIe ClltCnt. this is due luche genernJly locillised nnd 
Jilil.·unltnuuUs nature 01 ;ulullcrs III uystalline bOIscmelll rods 
nlc (ransmis.... . ivily \al~5 obtained from 23 ~Iallltit,; rll(k 34uifers lange 110m 
2.610 lOS 2 m:/day . '11"11: ;I\'cragc and standartl deviation "alues arc 33.2 and 27 .0 
m 'ld:t)' rt"r-:I.:tlvely I'our a'lulren in the ~recrulones were evaluated ror 
transnU~SI\' II)' ,·alues . The ulucs vary between 8.1 aoll 107.3 m:/day . An average 01 
48.0m1/dayaudastandarddeviaiionof4S.5 m'/day "ereuhlained 
Tnnsnllssivity valu(,5 for 12 phyllitM: rock aqulrers r;ml!(' rrom I 2 to 90.3 
oblalnccJ 1Up'-"(;:!I\"CIy. I;or eiaht schist &qulren. the IrammlissivilY "alues rall~c 
between 7.2 and ~ 6 m:/day The aver.l~e is 33.6 m:/day and the 51andud dc:vialion 
is 31.2 m;/day 
112 
i=~  e University of Ghana http://ugspace.ug.edu.ghIAbt.c ~,, : :IIuMMA" V U f' "t.lu,rl:.to: l,;u ... RACTERISnCS =~~)N ;::;6~ TRANSMI SSIVlTY(m'ldil't} 
(m'/diiy) 
,fSIH' 
Phylite 
4DC1f5 Duong 
1OOF2 
Phylite 
1m 11 
:J1E2 y ....... 
Sampna 
III 
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Jt,£23(cor>I'IUf"1 
JREHOlE DURATION SPECIFIC TRANSMISSIVITY (m'Jd.y) 
......R  (HOURS) CAPACITY i--r-:--,,----:::=-i 
(m'/day) 
Wlilcalholic 
semio_, 
Ouon, 
Phyllite 
JiJ..,.s.c.Sch 
11101' WalamanYlfI 
S6ng(W.} 
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Chilton and Foster (1993) cJjscusscd (hat low values of transmissivilY are likely 
III exhibil slgnifJCan( vanaliun." In yield and responses 10 abstra,lion This is 
r.:haract.erislic of the yield .. aiM.! lIaml1lism 'nies obtained fWIll aquifers in Ihe slUd~' 
arC;t IInwcvcr, tr3n.. . nU~I\· UI('~ ;1IC ).!cllCrally higher in the gr' IIII"r.; rock "qulle~ than 
The !lrtlIlI number vi aquifers enCt~lIh:rcJ III the f!reensit)lle!O lIIakc~ II 
UIIICplcflCntatlvc I{lr any ILlcalllnt-:lul discussion lhuu[!:h the highcst average 
transmissivity \'iIllue uhlalllcu in Ihe Sludy was in the greenstone aquilcu . The ~me 
obJ;C(vation waJi JlI:.de by Banoeng·Y.lrubo (1989) from his studies in thc calcul:lIion 
or lransmissivjly values from ):reem.lone rock aquirers in the Upper region.. . of Ghan.1 
USing the Theis RtXovery method, Ihe u;lnsmissivity va lues for w; hureholes 
range from 19.5 to 213 .4 m!/day The a\'era~c \·alue was 82 .3 ml/day . Those 
r.:akulalcd from the sallie btlfelK.tlc~ u"m~ Ihe Cooper·Jacob (1946) sulution Icduuquc 
gave a rani!c hetween 24 .5 and 183 .4 m~/day with an .\·era~c value of 75 .2 OIl/day 
rransmisslvilY va lue~ rrom the r«o\'ery dal:ll are hlghcrlhan those obtained 
from the CHup:r·Jacob (1946) SOlullolI tc-chni4ue . This is ba:ausc, dUring the 
recovef)' period. water levels arc mea~ured without any interference from pump 
:~:::'~::~:'SC~~::.il.": ,:::'::-'·"~h1 "..,   
H 2 SPF.nE!l:_£Al~AQIJF.~ ~', - ) p -
l)ri!oCull l1989)llellll(.·' ,'. ....· \.III..:..:ap.lCu)' ora well aSlhe ralC ordilC hargeper 
uml drawdown. SpecirK: C3pal:ll)" var l('\ wllh lhe dural ion of discharge Esscnl ially, 
lhe IIIne at which lhc spa:lflC capacity t1r a well is obained is very ncc:esary . 
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Olhe:r factors which mflue:oce the: ~pccirtc capacity of a well Include thr hyLlraulic 
dW<lClerislic<; of the: aquifer. the poI'tlal or total penetration and the efrective open 
.rrc..lllllhescreen(llrCf<;ehenk.I963) 
rhe spccinc capacities of six burcholcs It:sIL"(j Ivr 24 hours tluring the stutly 
III Ihe W,r well fie:d~ were compuu.'\J (lVe:r the tcsl period . A l11inllllUtll sl"I«ific 
_~IX hurehtlle .. 1lIe avera~e spec II",: capacity valut' i .. 40 5 m:/day an~1 the ~I;uward 
devlalion I" 41 7 m1/day. A~am. Ihis exhibits the wide II1ca~ure of dl~I"lCISllll1 111 
speciftc capK:uy vJluc$ in the stooy area 
Porty-sevcn boreholes tested for one hour have specinc capacities ranging 
from 0.7lO 101.9 mJ/d;;ry with an average and !itandard deviallon value of 22.3 and 
24 .9111:ltlay respa:llvcly The OImOUIll ofdc\-iallun fromlhe mean IS high, which 
CXrlalm the helerugcncousatwJ lucali5Cd nalUreofal.lulfcr in the re)!1I1II 
Gramtlc rock aqulfef5 cncoullieraj in 23 bmehule~ tested ft.r line IWllr OIWJ 
have ~Jl",.'eirK: capacity vallie .. ran~UlI! between 1.4 and n .o III:/day . The average is 
varying frum 3.9 10 55.9 m:/day furcight aqulli:rs The siandard devialion is 21.7 
nit.' ~pccirlC Orl(IUCS or wells tested hIe liRe hour range from 0 .7 ml/day 10 
% 5 tn : d;t:- til !loItCl\' C' 'Ih) Ifillc il4ulfers . The mean value is 21 .7 m1lday . Greenstones 
have ~rc(llf( ca~ity valut."S varYing between 4.3 and 101.9 m:/day wilh an avcrale 
(If J7 4 m:/day in four boreholcs fesled furune hour 
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nw: range and stalk!:IIO oC\'I,ltion v.1UC$lIrl"pccifk cara<=itie~ohtnillaJ in the 
vanuus rock aquifers devialc 1!rcatly from their me .. n wilh common wKJe disparities. 
ThiS may he due (0 the taCl'I~1. aqUlrers In lhe study area are variahle in extent. 
lhickncss, composilion and hrJuuhc ch.1faClerUlics . The variable litholOfic~ :md 
del!rttsof fnclurinl! inler!IeCtC\l by lhe bureholes.lsoaccount forlhcsc d,"crcnccs 
in .. p""CIIK.: .... p,lcilyvalues 
Chillu" and Smilh-Caringlon (1984) agree that thc;\C spedne capacitlcs .11C 
ent)U~h to sustain rural water sUWlies. Sixty pen:elll of the boreholes tested for one! 
hour h;lvc specifIC 1.:'pa"IIC\ ul ovcr 5 a m'/day. ;'\ lIu",mum value required In 
achtc"c a Village water supply IIf IOI/min 
Hale!! el al (1992) reponed hI in the crystalline b3~emem rockl- 01 Kalin 
"Iale in Northern Nigeria, the mean !ope-dr.c capacities of undifferentiated gramte!> III 
wealheroo alk! Iraclumi aquirers I. . 14.9 ml/day .Uld 16.9 m'ldl), resl'cctlVl:ly . TI'IC 
average specinc capacities obtatncd from the we:lIhcrcd ,1(jUIlCI\ in gr<!.I1 itc5 is 17.6 
IIII/day In (he ~llMJy.rea."", thaI obtained rrom fractured aquifers is " .8ml/day . As 
dr.lwdown increncs. there IS a m.ukcd dl"\.rea<;c 10 the spa:ific a.:ap:\cily . Driscoll 
(1989) expJaUls thai thiS det:reasc depends un the: ecologic ongm 01 the aquifer . 
From Table 13. hllth spc<:ifK ClpacllY values ale usually associated wilh hi,h 
Ir;H\<;lUi .... iviti~ From earlier dir.cusslon,. Ihe average specifrc: capaa.:lly values in 
phyllllC!i and SClllsl (ock aquirers arc comparable . However. aa.:a.:(lrdlllJ;! to Ajayi 
(19M7). the productivity of wells canonJy be compared If. pumpin~ period is chosen 
.nk.! the ykld of lhcsc wells tire .. ('I11pUed at a specifttd level uf drawdown. 
llw:refore. In real terfH~. II 1\ 1I1111wpe:r 10 ccmparc: the average spct:ific capacilY 
v.lyes thai hive been ootallk'd 
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5.8.3 I!!~VSSlOJ'l! OF ~'~EI)_()RAWJ)OWN RI~'-~I.J:.S 
Slep ·tlrawdown tescs were perfonned for five borehole5 in the Wa well rtClds 
The: analysis was done usinp: (he Jacob (I947) graphical 5OIution method 
A t:ilSC study is one 01 the W~ (Urban) South ·west boreholes in lhe well field 
Thi~ horeh<lk . WXI I:" Wil~ drilletl 111 a flatland and screi:net! throu~h granite. The 
fmaltlcptholtheho'r(;hulc \\ 58111 The ovcrbunJen thickness is 32 m;lIlu the tlcpth 
to lop of the aquifer is 41 In It has a ~Ia'ic water level of 9.02 III and the dyn.-unic 
waler level afler 24 hours of pumping is 32.18 m. 
A step-drawdown lesl con.~islmg of 3 sleps with eaeh step lasting for one hour 
was t:onducted by the Kumasi Drilling Unit of lhe Ghana Water and Sewerage 
CorpoJalion (GWSC) during the sfUdy The test was perfonned at discharge rales of 
130 mJ/day, 156 mJ/day and 176 ml/day . 1lle origin of time (or all steps is taken as 
the i>q!mning of the: test 
The format ton and well I()~s i.:unstallts. 0 allll C were calculalcd from equation 
(4 .16) a' !ihoWI1 lit Hl!urc: ZlI I he calculated tlrawdtlwn nhfame~ from (he values of 
11 and C Ire illustrated 111 "tables 2401 .. ,,1.1 24b The rOIlIl:llion l.)5s cOI\.~tant , B. is 
O.09b 111"1 day. The (ulmalion lou cUlI1ponent of (he tulal tlra,\duwn IS 16.89 m. 
Funhcr. (he wcllioss (On'I:1I1I (' is 0 OOU4 III ' IIay 1. The well luss component or lhe 
lOtal dr:lwdown i~ 12 J9 III calculiuetl for the "'me borehole . The computed 100al 
drawdown il therdurt: III .1M III The m:IUIllUIII JI"'h;u~e al which the step-IeS! was 
pcrlurmeJ fur IhlS burehole I) 176 m"da~· The actual drawduwlI aller 24 hours or 
rumplPlf is 22.98 m and the tlllil.:h.arge rate for II~ cunstant ralC lest IS 160 m'/day . 
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The errk:ICrM:Y IIf Ihl~ hurehole after one hour WIS (akul3lcd rrom Ihe ralio 
nr Ihc lurmallon lollS component. [)Q 10 the: lotal drawdown. S. (Jacob. 1947). The: 
dlide:ocy or borehole numoci W81 IS alkr line hour of pUl1lpUl)! is S8~ . This 
Implies (hOl( Ihe well 1(1,,-, (;umpuncui. CQJ of the lolal dta\\dt1wn has illtfIJoul.:'CO 
IlleflkJcnclCS II) the: borchok: perrorman(;c by 42~ , 83110CII$' YaKuhu ( 1t,l89ImdlcOItcJ 
in his studies that such inclr.clerlCrcs introduced by the well loss components hinder 
groundw;ucr ahmactions and si~njficantly reduce the yield of the boreholes 
Corrtclhc measures such ali the redevelopment and rehabilitation of the 
boreholes ~hould be implemented to remove these inefficiencies . MOM or Ihe 
boreholes should be pump·tesled ror a longer duration 10 delermmc the aquifer 
raramclers and how su"ttunablc determined yields are when projected over Ions , I 
periotls of rUIIIPIJl~ 
Re~ults uf the step·duwutlwn analysis shown in Table 15 were used in the 
calculation of borehole cfficl1;nclt:s after,OIlC ho, ur 0, r pumpHl,~ 'lllC resuh indiC8le
...
thatntlntuflhcboreholesanalysc~hadlllcfficlenclesexcecdHlg75%. "'d(!R.. \011' .."   
it , 
~.. ~  ;;, 
19 MllLt! ,[. 1 nJ:~tr<.J)J!."':I!}'Uill!'LJ)"-!'-!,R~VIIEltQl.t;S ~'''' ~> 
Gwundwaler U\.lUI' mainly within lhe O\'ClbUiJen and in (raclures within lhe 
t,,:Jllxk Three types (If aquifers havc been identified from the tJrllkrs' l o~s in the 
Upp:r Wesl Rc,.ion 1 hc~ .lIe Ihe weathercd rock aqUlrers which Irc Iracturc, 
related. IIIe IracluretJ UIl\\"c.lllM:H·U rock aquirers and Ihl' liaclurW quan1.-vclII 
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\ 
o 
~ 
t--t----f-~- t -- - - - 1--
! ~ ~ 0> -0 
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TABLE 24.: 
CALCULATED DRAWDOWN FOR STEp·DRAWDOWN PUMPING 
TEST AT WA (BOREHOLE NUMBER 3981 • 15) 
USING RESUL TS FROM PLOT OF FIGURE 20 
B = 9.6 x 10·' (m'/day) 0.096 (m'/day) 
C 4:1e 104 (m'/day') 00004 (m '/day') 
TABLE 24 b: 
Qlm'/day) Balm) CQ2fm··) SW_BQ + co· 1m' 
&-0.0004 m'day' Co::O.OO04 m'day1) 
121 
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TABLE 25: 
Summary of FormalM)f1 and Well loss Components 
of Totsl Drawdowns Using Jacob's (1947) Method 
s •• 
Ikw..,.. Nu~ QWAJI: ~ oJ .,m-' 
~ OfSt~ ImJOay) 0." 
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\'IIIIIC!' III IhI: \\t::athcH.-J /I'ne an: well tJt::\'t:lupetJ a~ 1~ Cllnlll1(1nl~' the Ci1~ 
III .• hll"q \C\CIII) -Iu'c relCCfll III the rocks in 11M.' stutJy area . Vil1ually . all the 
Ulllltl,tIIJ1g waler moves Ihr!)Ugh Ihe weathcrctlzone belore \I I:an ptrcolalt into the 
deep fr-'Clure systenu in the fresh unweathered rock . Thus, groundwalcr is siored 
Il1Insicnily inllIC wcatheretJ zone 
This gmumJwater J,!~'llCf;llIy tOrillS if conllOuUI11 with Ih.11 stored in the deeper 
hacturc ~yslcm or lhe hedruek _ In sume cases. the fractures itrl! inler'lM.'fsetJ wlthlll 
the wc:uhercd Lnne 
l)urint!lheprojet:tinthemitJ-scn:ntit's.lheboreholetJrillin(l:prugraulIllcwas 
basIcally focused on OblaJIIIIIJ,! yields rt::qulmi for borehole completion fmm the 
weathered zone . 1l1is policy. Iherefore. affectec.! how tJeep the drilling should be 
clrriet.l OUI. tK:nce upl.lInlRg why most boreholes in the siudy area Were complelaJ 
1ft Ihe moderalelydc:compo'iCd LUrICS 
AIIUlreo. were ;dSt) encountered in rock~ where fraclurcc..l quartz veins 
travcrset.!lhe rocb. "'IC'IC aquifers are normally observed to be very prooucttve. 
Yiclus ;tn: «:nhar..:ctJ .... /ICII many fracturt.:tJ quartl \"('1115 cross t;ul Ihc rocks. fire 
Iracturc' sup«:fJmpo!'i(' ,<cmadary purusity un the rocks and incrcaSC' thcrr poroSltlCS 
and pcnneatuhllC' 
Amollit the twenty-three obscrvalion borehole». <;'1lI.tt.'cn were tlrilk-d in the 
graniuc terrains. wblle 1"'0 w«:re ~omple1cd in Birirnian phyllites and five in the 
Ihl"uran SChIM( In Ihe !!,r:lI1l1oids. twelve boreholt::s obtain Wllcr from the "cathcrctl 
/nlle ,1l1d I"UI til lhe tlorehu/t:<I; lapped water from weathered zones within the 
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About 61 S of the boreholes were mainly completed in the moderately (0 
slit!htly weathered lOnes as indlC:ued in (Table 26): whilst J9~ or the moolloring 
boreholes were completed in fresh bedrock. Nu'IC of the monitoring boreholes tap 
walCrfrom fracNred rock aquifers 
Genel'311y. 65.2~ of the monitoring boreholes obtain waler from the 
we.uhcmJ zone, while 17.4'- of tbe boreholes ~\'(: aquifers in fr.a.crurctl rocks and 
frac.:lured qUJnz ~'elncd rocks respetllvel)' (Table 27). For Instance. borehole 437E 
5 at Furo "bulIls w.uer lrum a decomposed fractured quartz vein 5Chi~t and borehole 
40IA 7 ups water from a weathc:rt'rl schln lqulfer at Jan! . The weathered zone 
u\u.llI~ ":lImpn-..c:s an:a.s of deep fO'k <kcumposllllln anc.l are cOllSldered to have the 
hl~he~1 Pl"entl.11 fur \ulo:cessful bureholes ...... Ilen fractures anJ 'luo.lrtl n:IR.O; are slre ..... n 
'Allhm the ..... cathc:rttI zone. lbe presence of thc:~ structural Ic;uurclo -.c:rve as a guide 
\\1 lunhcrJnllmg II'IlO the fmh bcdrock 
Tahle 28 IIldicates thaI abouI74.S% oflhe production horeooles lap watcr 
from the .... eathemJ zones whilst IS~ otn;un \.\-atcr (rom Irat:tured "Iuartz-vein rocks 
;mu IO~ receive water from fractured rock aqUifers In Lawra. borehole 437E Slaps 
"au:r from a fractured ~rc:enstone ilqulfer . while at Kodouni. borehole 398G 4 
n:ccm:s .....1 Ier from a fraclured quam vein pbyllilic aquifer 
A closer study of the borehole lop clearly reveal that about 70c;t of the 
"4U1fers in the production boreholes an: within areas of moderately (0 sligbtJy 
","CdlheredZOReS. 
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TABLE 26: NUMBER AND PERCENTAGE OF DEGREES OF ~THERING 
IN THE LITHOlOGIES Of MONITORING BOREHOLES 
Degree oJ Number of Percentages 
Decomposition Boreholes 
Hoghly 
Weathered 
Moderately 61 
Weathered 
Poorly 39 
Weathered 
Total 23 100 
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TABLE 27: NUMBER AND PERCENTAGE OF AQUifER 
AQUIFER NUMBER OF PERCENTAGE 
TYPES BOREHOLES 
FRACTURED 174 
QUARTZ VEIN 
FRACTURED 17.4 
WEATHERED 15 65.2 
TOTAL 23 lOa 
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TABLE 28: Numbers and Percentages of Aquifer Types In 
the Producllon Bo(eholes Upper West Region 
AQUIFER TYPE NUMBER PERCENTAGES 
Fractured Quartz Vein 26 15.5 
Fractured 17 10.0 
Weathered 126 74.5 
Total 169 100 
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TABLE 29: Number and Percentages of Degrees of weathering 
In the lithologies of the Production Boreholes 
Degree of Decomposition Number of Boreholes Percentages 
Highly Decomposed 20 12 
Moderately to sllghlly weathered 119 70 
Poorly weathered JO 16 
Total 169 100 
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About 12';(. obtalO .... ater from the highly tJ(,(lIInroscd wnes, unlike in lhe loolllturing 
bon:hoks where no borehulc laps waler from the lu)!llly decomposed ZOI1e5. 18% or 
the production boreholes obtam waler from lhe poorly tJet:omposed zones (Tahle 29) 
rhe net ..... ork o(groundwater monilori", of boreholes produces a sct oftJala 
.... ·Imh deplct!i Iq!lon:J1 \';ITlaltoUS in thtquanlily and qua hi)' 01 groulk.lwatcrnnd 
lacl(lr.~ alll..'i.:llnJ.! thc~ varialiun~ in ~eoloBica l . topographical and clim31tc 
envimnments 
MUllllunngboreholes inlhcstudyarcaalt's(X"ific boreholes used IOpn.wJucc 
""'ller and It lhe same tllne III mURlior pnwJuclion boreholes thai ~urround them 
AccurdinJi! III Smcn (1~J4), IIIUlllltlun~ may be "'dined IS a scientifically dcsignciJ 
~urvCIII;IIM.:C system 01 C1I1I11II11Inj! IItca!iurcmcnl~ and obscn,.uions iuduiJm.,: 
prucCillures . Moniloril1~ H.-qUilt:' Ihilt iJata is obtamed un a reJular balils. when:h~ d;ll" 
can hcellcclively U!IC'tI Itltldd bulehole performance which is vital iflhc IllOIll II11UIII 
long term yield 01 a horehole IS 10 be reah!oCd 
Gruurx.iwiltcr monitori .. has Ixcn possible mamly in the use of ub$cn'3liun 
hmchnles. However. lII\'c\ligaliofl\ wnJucled by Bannerman and Ayibolclc ( 1984) 
in the stwy area :.ug)tClot that lhe most efficient wly 10 manllor producliun borch(.IC'I 
IS III use lhe bon:h;Jlcs themselves. sinc;c Ihe normal praclice or havinJ! SCp.U3IC 
htllcholes Itl momlor lhe performance of PfOiJUCtlUIl boreholes wouliJ eventually 
H1\t,h ~- hlj!h ellsts and log'suca) constraints 
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During the pro~cl irK:eplltln hy CIDAlGWSC, • network of 2.1 "b!>en'allon 
1"llChoklii werc eslablished Ihroul!hout the region to collect inrormation rclale<.l ttl 
)!n1tlIlJ\\OIICr level nu~lualluns 
FIJ!ure 21 !ihoViS the location of Ihe\C borehule!' and S(IIIlC producllon 
boreholes surrtlundin(:. them The observation boreholes were sclectetl upon Ihe bam, 
o( easy access to <.Iala eoUa:tion. 11I!!h yields and low drawdown due to pumpinJ: 
Todelenmnrlheadcqu;u.:) orother\\,I:r.ct)l lhce.ll.lsllngn~l\\nrk('lllhserv;lIlOu 
boreholC5 momUlrmg Ihe aqUlkrs being rapped in (he Upper West region. IllC relalion 
of the groundwater monitorin,: sy~tem wilh the hydrogeolo~l!.:al l:uuditions of 
procJucingboreholes in thcfivedwllclshave becnsludiedand \'erirlCdin the preseIII 
"Iudy lla~cJ on the findings. il would be delennined whelher or nUl the currelll 
monitorin!! boreholes an: representative 0' (he: proUu":lIon boreholes. From Table 30. 
elevallnns above mean ~a level of some boreholes were measured wilh rhe Global 
Positioning System (GI'S. (iARMIN 75) durinJ the study These elevations I~ve been 
ustd to rethKC the 1>(lfclKlic depths aoo aquifer dept/as to mean 5(':1 level as refe~nce. 
To Invesligale ...· hethcr the monuoring bon:holes have an.v hydrogeological 
rciallUllShip WIth the PHK.!u~Utln ~'reh()les surroundinll lhem in the study area, 
htlll,'/tuic depths arK.! ;aquirer depth!> \\ere I.:ah:ulaled This was done with a "ICW of 
hndlll~ (lui II the~ IIIOl1llOflng boreholes ....· ere complelt'd in aqullers that bottom It 
Iht' <;;IIl1e Jeplh, a~ lh(l~ of (he proouc:tion boreholes surroundJn~ them . 
Illlhe tJlliilnclul Tumu. five observation boreholes were studfcd alOIlIl\IJe with 
IImtccn produchon h"'~'holes 
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Obscryallon oorehole nlJlnbcr 444F 2 It)(atro in Puliml is _hool 2 .5 km from Turnu. 
the cJlr.lricl capilli!. l'nxJucltun boreholes 444F 4 .nd 444F 3 arc aboul 250 m antJ 215 
m away from the observallon Ilorchole They were all drilled III na(lamls and up 
..... ter from weathered granittc-gociss rock aquifers Observation borehole -I44F 2 aut.1 
the prCMJuCIIOI'I boreholes h.ave the same aquifer thicknesses of 6 m. 
rile St3tt( water levels in the ubservallun burehole and the pmduc.:tlllll horehule 
444F 4 are almostlhc S.111lC wilh yalues of 5.8 m and 5.2 m respectively. while the 
SiaiK water level of borehole 444F 3 IS 2. 1 m and is 275 m from the obscrv;ul(m 
AquiferdC'pths allove me. . " sea level vary inthc produclionand observation 
hmchnh:\ . The lh:Plh IQ top of the aqUifer "hove mean sca level is 451 .0 m in the 
procJUL:IIUII borehole 4-14f 4 ;HlcJ 320.0 m In Ihe uhservatlun borehole 444f 2 . l1lCre 
eXISIS areal vlnation~ In the yteld despite the (aellhalth.ese boreholes oblain waler 
Irmll the same rock type The: yield of lhe ubscryalion borehole is 103 .5 IImlll . ;and 
lllit flU che production borehole~ 444F 4100 444F J are 13,5 I/min , and 31.7 I/min . 
respectivel)' . 
nte hl~h Yldd obtained hom the observation borehole may be due 10 lhe 
presence of fractured quartz yein intrUSions mlerSttling the thick overburden of 23 
m which wu not encountered inlhC' prnduction boreholes 
·lllCfe is indication tb." there exi,;ts no hydraulic connection between the 
1'1"C;I\.Ilh,nbureholelndtheprotluctionboreholc\surroundinf! il . Thouf!h,lhe three 
j,orehlllt's h.I\C It.: same aqUifer Ihickncs'IC~. 1I)Clr yields. aquifer depth~ uboye mean 
o.c=alC'yelaf'du,'clhtJrdenlhlCknes.snaredirferenl. 
132 
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Evcn (hou~h dlflcrcnt:c~ occur in Ihc proper1ies of these horeholes. Ihry ubtain waler 
from Ihe ianlC rock Iype 0100 i'\julfer aoo arc also found in lhe Sollne tUflU8rnplJII.:al 
~tinlts 
lefflSi. a town situated 30 krn south·west of lhe Tumu township on lhe Tumu· 
lawra III~hwOly I" a tnwn m lhe Turnu di5CrK:t. Borehole number 4431 I i~ an 
ob!'er"31101l borehu[C whICh t~ allOUt 800 m away from the production borehole 
nUlllber 44312. 'nw; atluilcr depths above mean sea level in the observatiDn .,-.1 
production hureholes have close values of 300.8 m and 305.0 m tC)Pl.'t:tl\·cly 
However. the production borehoie yields 99l1min. of waler from it weathercd rock 
aquifer or granitc·gneiss with an aquifer thickness of 6 m whilst the ubserv8lion 
bo,t'l.,)lc }It'lds 22.5 I/mm. of water rrom an aquifer IIl1dnc.~ .. of 4.6 m. The 
~l\'aIIOIl bordlnle \\'.1<; dulled in I wcatheretl gramte-gneiss J\l(..k aquifer. They 
bothuccurinIJallaoo5 
Eight hundrt'd IIlClcl~ <lp.lft, Ihl:sc Nllt:hulc1 differ in a~uilet IhK:kneuea wilh 
\,ary,"" y;clds as well B(Jwcvcr. Ihere eXISh ,\ 1lgntfu:anl hydraulif.: IlIlk hetween cite 
ob!.ervaclunburehoieand proouclionboreholcssurroundtng II, bccau.'OClheylapwaacr 
lrom Ihc ~mc tuck and a~uller Iypes_ In addition. thc~ l)(;CUr to the 5ame 
lopugraphy and hive close values uf '"Iuder dcplhs above mean set. level 
At Nandaw.la. aho in the Turnu district, borebole number 44JU I. an 
obl;c:rvaltun borehole was drilled on a OatJand and compleled Ihruugh .. "calhc'nl 
gr.mIlJ~ ~nt'i ... , " ... 1.. .Iqulrcr . .\ \1oul 40 m rwm IhI: ob~t\laliun borehole IS d 
pm,JueltOn 1'I'lchuh: number "'4111 2. Thts I:>mchole is .ilUlled on. hillside and .Iso 
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Uoth the: t1ibservalKJn and production oorehole have the: sa~ ~atlL: WOller Icvels and 
aquifer thic:knes.5C'$ with values of 13.4 m and b .1 III respectively 
rhe observation borehole has a yield of 90 I/mm. and aquiferdcpth aoove 
mean sea level of 270 m . The overburden thlL:knc»s is 17 m. whilst the produclulIl 
horehule has. yiehJ ofQ 11m in with an aquifcr dcpth above mean sealevel of JIJ 
In . The overburnen lIuckneu i~ 27 m. It implies thaI. though the prodoclion borehole 
IS quite near the uh~rv;uion boll:oote, it was !iitu.ted at a hyt1roS:CH111~u.:ally poor lite. 
()eosides. moderate {u high yiekls are nurmallyexpected (rom boreholes drilled on 
natl,mdsandvalleysthanonhillsides. ~ 
Despilc the lIOOft disunce betw~n the tWQ boreholes. lhe differences in yield ~1r (Jl 
and aquifer deplhs above mean sea level. IS well as the topography in which the ~",.}. J 
boreholes were located. indicatethallhere is IlOrelalionshlp bclween lhe observation ~ 
borehole and the pnJduciion borehole 
In the liraPl-Lambuss!C illstm;l. '"ur IIIl1llltonng boreholes ;mil forty-five 
prudUl:tlOIl h()ft'h(llc~ wen: sIOOK.'tl Ob5('rvaHo[l hurcholc number 4380 3 I;OIllPIC'kd 
tluou~ a weathered grcemlQOC aquifer IS found In Jirapa- Vipal.. This hurcholc is 
ahuut 100 m from. producllon borehole numbl:r 4380 1. 
This burehule was however screened through a weathered granitic rock aquifer 
ina nlttand These twO boreholes have equal Yields and aqUifer Ihickrleuesor 1).5 
'Imlli. and 12 I III each. dcspile the diffel'm rock types In which they occur. It i~ 
p;1~~lble mat there was a fractuR: rcJalN ~uanz VC'ID I;ystem COf\nC'ctinll the: tWH 
hnu:holes . Surfa,,:e mani(csuHons also HIlIit,;atro Inc.allsed zones: of 4ualll \<cins 
surround. .. lbe borchoks which bad a relativC'slgnificance 10 lbeIlydrogcology . 
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Overburden thicknesses in lhe two boreholes are ahuOliI Ihe \3n!e wilh 15.1 
In m:unkd ror the observalion well and 13.0 m oblamed ror the pfoducuon well. The 
dcpi'hs 10 lop or the .. quifers above mean su level in the ob$crvalion and productiun 
bmehulc!> arc respt::l;"lIvely 301.6 m and 304.0 m 
IJt',)eII<.hn, on the distance between Ihe two boreholesall(J theaquirercJepths 
above IIlC. . 1I \Ca level as well as (he Slruc.lural systems ~'onnecting them. they are 
likely to bc'la\'c in a hydrauhcally !!IlImlar manner. lIowevC'r. Ihc extent of hydraulic 
link IS minimal SIItt:C 11I01ll10rin, mlY nllt he qUIte eflct"tive in bt)rcholcs tapping waler 
fromdlllclcm rock I}PCS 
Oh.\CrvaIIUIi bmchole 438A 3 a( Zumara m the Iirapa diSlrict IS the only 
borehole in this lown. It taps walC'r from a fractured greenstone aquifer in a n.uland 
It has .In aquifer Ihkkness "' J.4 In and aquifer depth ahove mean SCI level of 264 
m. II prooucc.lo Willer al a rale ur IS I/mm. Production borehole 4J8A 4 OIl lJa.mll~ 
alI!J 4.H$A 5 .11 i.ISsa 10000:lIed ~ 56 kill oIIl)(j 1.35 km ilway from Ihe obscrvalluH 
bon:hulc Icspt.'\.II\'ely also t.lpS water III a l1alland from we311lClcJ ~rttl~lltl'lc 
aquifc:~ 
These IWO production boreholes produce the same yield or 22.5 I!min of water 
and .. hI! II.I"'c the SJlme aquifer thicknesses of 6.0 m. The aquifer deptlu above mean 
!iCa level III 438A 4 a,)(j 438A ~ arc 349.9 m and 238.0 m respectively. The 
o ... cfburdcnthll.:kucs.scs ob. ... ned are 23.0 m and 28.0m rapcc:11\ldy 
Due ItlthedlStances. different aquifer types "lid aqullcrJt':pllu "bovc fnC'an 
sea 'cvcl betWttfl the monitori.c borehole and the pn)f.)uction borcholea. there IS no 
n:lalMlnltllp becwcen these hocThuks. therefore. the produclion boreholes are lkJC 
hclnJ!:monll~hylheub5,crvolillunhllfehtlle 
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In Tuopare. observation borehole number 438C 3 was driUed in a Oalland and~  
screcnro throogh a wcalhtred granitic aquifer . 'Ibis borehole produces 18 I/min. of 
waler and has an aquifer Il1Ickne~s of 6 1 m and aquifer depth above mean sea level 
0(280.7 m . A production borehole: 438C 4 in Gud which 15 aoout 4 kill away from 
the obc;crvatloll burchulc in TU(lparc was also lhlllec.J in .. nal/and bul laps water fmlll 
.. w~: .. lhered greenstone aquifer. II PWt.lu\:('<; .. )' Icld of 18 "min. and has an OIqullcr 
thil.:krrss nf 6 m The ;aquifer depth above: mean sea level is 327 .0 m. The s.amc 
hydrogculogkal WIMhllllllS cool'" he perSISting at these two places despite the disLlIJcc 
hetween the boreholes. However. due to different values of aquifer depths above: 
mean sea level and different rock types, thcl~' exisl<, nu relationship betwC1:n them 
SevenoDscn'auunwelJsand fifly·scvenprooucllon borcholeswercstudted in 
Ihe Lawra district. Ob~rvation borehole number 4371{ 9 in D3bile was drilled 
lhrou~h a wc:alheroo )!.r.1l11lic Iquifer in a valley II has an aqulfC'r thick.nessof7 In. 
rile: .qulfer "'cplh a!love mean SCI level is 220.5 m . 11 produces Wiler at I nle 
of 22.S IJmin an'" has a HallslUlM.ivilY value of 12.8 m!/day Prudoclion borehole 
43711 17 lu~led ahllul hOO III from the observation borehule CI)(QUlllercl.I water Imm 
a weathered rock. .u.luller In ,rarnlc It Ills an aqUifer Ihickne$s of 6.1 m and yields 
waler al II rale uf (] 5 I' nlln The aquifer deplh above mean :;COl level is 272 .0 m. 
I;H'U Iht ... )!h the tWI! hort'hules lar "'OIlier ""111 Cill' ~ .UI\C I''l\. hpc Illn Ila'C' 
n=SUJlml! 10 110 ubvious hydraulic conneclion between them . Tlle:rdurc. IIIe: 
oh"c'n'''"{1l1borchoki.snotrcpttlCnll'tveQrtheproduc'ion~holc=sinceltdoesnll' 
muml,,' the hnreholessurroundintit. 
136 
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UOlToole number " .171::. I is an obJc:ryallOn borchok in Valtluuri. It oblains 
waler from I weathered phyUiU: in a yaUey . It yields 21 Umin. of water and has an 
aquifer thn;kness of 6.1 m. The depth 10 lOp of the aquifer above mean sea level is 
241.0 ... 
Similarly. p,odlll.::11lJ1l hmchole 437E 2 in Vagluuri is aboul 600 m from 437E 
l. 11 prutJu/,;c=~ waler ill a rak: 01 I K I/min . from a wealherN phyllilk ;uluifcr in .. 
vaHey . II ha!'! an ~lufc:r tilldlk'" uf 6 .0 m .00 an ~uifcr depth aboVe mean sea level 
of 1.51.0 III 
Annlher pruduclion bmchoie 4171; 31 41150 siluatcti about 1'150 III frum Ihe: 
oo.'Cf'Valioo burehulc (4)7E I) WiI\ M:rec:nc:d IhroU!;h a Irat.:lurttl phyllile 3qt.llfer with 
qu;utz veins intruding the phyllile. but this borehole is located on a hillside and 
pnlduces a relJlively tow yiekl of 9 lImin. 
The aquifer Ihiekneu 159.3 In and aqud"ertkplh lelall\e 10 IIIC;III!>Ca level is 
260,0 m llJC h l14' yield of 11m burehule rna)' he Joe 10 its phy5iu~raphil.; loutiun . 
DuC' 10 Ihe different aquifer depths above mean 5Ca level and the different 
aquirer lyflCS (rom which tbe monito,.n~ and production borcho~ lap water , lhere 
c.\i~s no hydl'OlcologK:al relaliomhlp belwcen Ihc monilorin, borehole and 
pmluctionborchulesatYallUuri 
Five nWllilorin, bm dkltcs were established in 1hr Nadowli dil4rict , TIlne 
.... 'CII~ WCK ShKJ ied .. h>fll!'ii~..k Wllh 'Cvenly ·I ....· o production borcholes in lhe districl 
Horehok number 4031> I i~ a monitori", borehole located It Fian. II obtains water 
(rom ill rr.Klurcd granitic aquir~ ill • n alland . II products water 411 a nee ur 4 .7 
The aqui'erdeplhabo\lc mean Ita level 
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Apprm,llUillc:ly 700 m fflllll this tmser\'aUon burcho~ is • production ooreholc 4030 
4 also In Fmn. h is ~ilualctl on a hillside: and "blains water frum a weathered I!rallltM: 
.. quifer , It y~Jds 9.2 IImin uf water and has an Aqulfcr thickness n( 7 III . The 
aquifer depth above mcan sea level is 298 0 III The topographical locatiun of the 
production borehole is unfavourable. but il ha5 a higher Yield than the nhscrvallon 
ho~hulcduelothcpre~nceofalhickeraquifer. 
Because of the different aquifer types Ihrou~h which tI"lCK 1.. .. ,rt'tKlle$ were 
S(;recnedandlhc(.h lfertnla~Ulferdcplhsabuvemeansea levelofbolhlheproductitln 
aoo monitorlllg borehole. there IS no hydrogeologll:al sllmlarit)' betwccn them. '11M: 
monilorin~ hurehole i~ nol representalive of lite production oorehole 
UOfchole nUlllher 4UOD 4 is Ihe only borehole Ihat is pumped ror domestic usc 
in biri. It also serves as a InOl1ltorill~ borehole in the vicinity 
Ifobtain.~ waler (111111 a wt!alhercd schist aquIfer and is located in a valley . II 
yieJus 27 IImin of waler alll.l has <lin aqUifer thickness of 9.2 m_ The depth 10 IDe lOp 
of <114ulfer <llbove mt4ln se<llievel is 288.9 m 
Produclinn borehoie number 400D 2 in Tlnll;tsil is Ibout 4000 m (4 km) .wly 
anu laps Wiler from I we:nheret.l greenstone "4uirer , It yields waler ;tt iI rate or 27 
I/mlll and ha .. an aquifer t1m:kncu of 12.0 m. !'lie "4uirer cJepth above mean sea 
HIC f:c:ulugy which l.!o ""porum in the 1ype III aqulrer cJcveloped and Ihe 
spacing between these two !1oreholes is 100 distant for an)· represemalLvenessdL)C.to 
Ihr localised Jl.1turt" of .a~ullc,~ in the region . The same values 01 Yield in these 
boreholes Inily he due III Ihc occurrence of fraclure: openings <lind quartz veins 
encountered during drillm~ <IInt.I possibly . the: deeper e,\tenls ur weathering In the 
dirfelcnt wd Iype~ . Ho\\'c\ct. Ihe rock types and Ihe a'lulfer deplhs ,,11(I\c mC<IIn sea 
level IIxhcOile Ihal the monll(lilng borehole and Ihe production borehole <lire nul 
reprcsenlillive o(cach ocher 
.l11c W. dislrK:1 has only 'Wo momtonRIl borchDleJ. These borehoks were 
stud~d with sixty lItree prodtJCtion borehofes In Gurungu. oho;ct\·,;UIIIII borehole 
••, mber 358 C J was dulled Ihrough a fractured quartz vein ,ranile on <II 'HUsick. 
II ytclds 90 I/min. or woller and has an aquifer IhM.:knesJ of 20 rn 
138 
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A pruduction borehole 358(' 1 about 400 m away from 358C 3 I~ III .1 n.dland anti 
wa~ (.:umplc'ted through 3 wealhered IHanilic aquifer. The ~Ialie water level is 1.5111 
below ~ruuntl level whilst the observation borehole is a flowing artesian well It is 
ooviou!> that the!oC borehole. . are not reprc~nlativc since they tap water from dirfr:rt'1I1 
aquirerlYpes 
Gurungu is ahoof 55 km from the district capital Wa. and il i.s duutltful 
whether Ihis observatilln borehnle is monitoring 50IIle production boreholes in aoo 
O~rvation borehole nUllltlCr 40lG 6" IIKh IS lue.ued ill Wa prudu..:es twenty-
seven lures of Wiler. It obtainS waler from I!. weathered granite aquifer ill a nalland 
Pmduction bordlOle 40IG 9 al Jahan College is about 8S() m away from 401G 6. It 
was drilled in a natlantl and compleltd through a weathered granite aquifer. The yte"kS 
i~ 4.7 Ifmin . with an aljulrer tluckness of 6. I m. In Ihis situalinn. there (.\isls ,·cry 
lillie relationship between the Iwo horeholes, though the yields arc quite tlillcrcnl. 
Lhey havcthc§.iltnealjuiferthklmes.scs3'wJ were drilled thrnugh the salllC rock Iypes 
The high) acid in 11K. observ~lion borehole may he due 10 the presence of quartz vein 
tntrusiuns perslstmg in the \Ioeathrred aquifer~nd its thick. overburden. 
In the r(llegoing discus!.lun, the study ha" shown thai hydraulic l:Unneclions 
between boreholes in the reaioll dept:nds on Ihe: (op4.lgraphy in which Ihe borehole", 
~re .. itco . Ihe lock type in which the ~qutrer IS eocmJnlered, the e:~tem of fraClurtn~ 
alw.l weathering in the rocb. th,:ayu,fcrdepthsarnwcIIK"ansea 1c,·e!;tsweIlUlhc: 
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The hydraulic link .. 110 are. . of innuence are limited in ~lrehole5 \\ III\:h are 100 
di~lnc apart antl I~ is mlllimum hydrogeulogical repr6Cnlltivcness in ~uc;h cucs 
""k:e.Hlullcr s)'stclIIsmerystallilll!tl,. . rnllnsarcliflliledantllocali~d innOiluTC , Even 
hnrch\lle~ locatcd ne .. readt othcreanexhihitlilrgedirrclcncL"S in horehole IJropertleo; 
The slul.hcs have indicaled Ihat there exists very linle hydrogeulo,M:al 
Id;tIIOn."IHP hctween monilUlin~ and production boreholes in the Icgiuli . II has been 
lIutC'd Ihat uhscrvalion hmcholcs localed about 150 m apilr( fmm ploouelioll 
boreholes and those with the ~;lIne elevalions and deplhs relative to mean sea Ic\'c! arc 
likely 10 rnonilor the perroml31Kc of the boreholes !'iurrounding il 
rile t:roondwalcr monitolln!! network seems ineffective due 10 the relalively 
small number of observation boreholes across the whole U.=glVll nM: uSC' ur 
PWUUClton borcholei &ll trlHllitonng bureholes in the: lIut1)' arta does 1I0t augur very 
well ror any me:ilnin!ful mmll1uring in 11)(: ~trlcteSi sense . Typical examples ciln be 
round in communities such as Pima. Tuopare. Zumara and Iziiri where there is only 
one borehole which serves boIh IS an ot.\Crvalion and produclion borehole ror a 
5Izcablcp...,ulalion. 
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O;:QNCLl'~I.o;.;S AlW "Et:O~I~IE:-;Il.ATI9NS 
6.1 l:P~J,'SI()i'lS 
J!'oIfllhllds. UirUIII,11I }!Iccmlulk". ~hi~ls. "ud phyllilcs The MKklk: I'rcc;unbrian 
granitoids and the I 'pper Uirinwm ~ICCIIMOI)cS ocl.:upy ahout c:i~:ltly pen:cl1l of the 
study area The Luwer Ulrimian .;chis!.,. and phyllitc:s occupy fhe rest of the area. 
Structural rcalurc~ such u fractun:" tulds, faulls. joints. pegmatite!' and quartz vems 
.IfC\.(ll11mon Inthebasemc:nt rocks 
(iruundwaler in the region occurs witlun the ""('tburden ... wJ IIIlra1,;tu~s 
wilhllllhc hc."tIruck . l'hi' uccurn:~c: ,.r ~nlUoowalcr IS IIIIUIII ctllllrtlllnJ h)' the dCplh 
allcJ c:",,'111 or frat:lurmg and weallW:IJII~. the prc:sclk:c "I a lind uvc,hunJcn and the 
nUllleruus rral:lures. quauL:tlkl flC'gmalllc: vcmsthat infersectlhe overburden 
rhcwcalhcfedrockaquifcrwhK.:hisrracture·rclatcd.lhefracluredquanzvein 
:uvJfracluredunwe4itberedrockaqulfcrCypeshavebeenidcntifiedinlhcarca.lliJ 
WOf1hDOlincthat thescaqullertypcsarcrclaled.ndoccurinassodalionwilhquartz 
vein inIrU$;uRS. pct'ITl .. llles ;llkI .. rlites 
The: wetthcrcd uw.:k .. quiret .... hkh IS nollDllly lI~wn with qua"l veins aoo 
fra:tl,l!'CS i~ II.: tJUlnlll;lnt type: of aquifer in the regIOn found in the: observation ant.! 
productIOn bon:htllc~ 
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..4J" ..\ f 
About 5I.iIIly fivc percenl of the hlrlncr laps waler from rhe weathered 3111111n and 
'C\'Cnlttn pcn:ent ol"llain waler from rhe rracNred quartz ve in and rrxnu~ 
un\\"':,lhc:l'1:'drvckOlQulfersrespecll\,cly: whilsllOlhelaller,unlYlcnpercerugelwater 
(rulll lra(lurcd unwr;u~'led "4ulrt'r~. :I!'IcM.lI !>C\'cnly five perccm OO(ain water from 
,hc\localhcrcd rockaljullcrsaoo slxlccnpcrc.:enllilpwillerfruOl rt,c fracturcdquarll 
vein aljuifers. A signirICant number of Ihe horchules wert completed in the 
mOOcr.llc:1y weathered 10nes flf Ihe mOnitoring and protJucliun boreholes . 
Rainfall iSlhcmaillsourcct1rrechargc llI;tl.lullcrs IIIlh(' rc(!:iun . The mean 
annual ramlall IS ahout 900 mm hm it varies (rom year to yeMf and (rom place to 
Recharge 10 alju,fers are inlcnniucnl Jnd limittd because of the barrier 
norn1:lUy formed by the overlying clayey decomposed rock . Reduced rC'tharge h::t!'t 
Il«n .. ggravated by cattle overgr.lllng. poor fillnnln~ pr .. ctl~~ :mJ t.!clOIeM.ltlllll \\11/\ II 
expuse the land turlace 10 ,I\(.' mleme ;u1l.l \t:un:hing rdY' of the !iun. The abow 
faclOr:'; UlclUlJill~ exce~"lvc wlthdrdwal III waler fwm borc=hulc, accuuru for the 
declineofwlterlevebinlhestudyarca 
Ninety pert:ellC of the: boreholes have depths bclWI."e1l 10 m and SO m. 
Generally drcpcr wells are cOlnmon In natlarxh than in the vallcys and hill!'tideli 
Overburden thK:kncsscs cltcecding 15 marc I.:ommon in the observation and 
pruJu(uon borehoks with a mean value of 24 m 10 the formtr and a tncOin of 21 m 
in the lallcr . I'byllilC!'t were notet.! to have slm,lar 1II(3n Ib,cknt\..es of 362m and 36 
In 10 observation and production wells respectively I he geulul!Y of the study 1m 
IWIIJrt:illmnucrx:eonoverbunJenthKknes:s 
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,,"uircrsan:slllalllllsJuallllmaycilu,isIO(vcinsoffrai.:luraJquilrllal)!J t1r 
Jc..'\.umrosaJ rocks up 10 about 30 m Ilw:k SomclIIlIcs thcy form .suilled pockeu in 
which the grouoowaler now is determined b)' the surface topography . Aquifers were 
noted 10 be thICker In flallands than in valle),!' 3.-.1 hillsides in .he $uld)' area 
Eighty fiyc perce"1 uf (he t'II.'fehulc'\ Yield :\0 lilrc!'hllluuh: ur Ie)) of water in 
Ihe ubscrv. . IKln and plVlluction wells There exisls large varialions in yields even wilh 
hurehoks lappin, WOller from tiM: gmc types of aquifcr . This rc:llCCls tlirrcrt"nc.·c~ III 
htlf'ehu/c pflJperl ics andsu!!t!csu a high degree of aqulft:r hClcr0itcllt:IIY III !he study 
arca . Reduced borehole yield,. in the reglon ean be allnbuled to siltaUon and screen 
clOlli~ (rom Ihe acculltulation of altered mtca pmdUt:IS mlhe boreholes. The decline 
(,(,\a.er leYel!' mlhe region can aiM) be a I.'ausc IIIlhe rcdut:llon of borehole ytelds 
makll1lllx:llorehule.lunablelo~alllaconljnu0ll5supply()fwater 
Tr;1I1SUIISSIYlIY values cOfltPUletJ from Coopcr·Jawb(1947) mclhod varied 
g~ally. The me. . n uan~nm'I\'Il)' oolalf'led (0(47 borehol~s te~l("d fur one hour j'll 35.2 
Wilter level nuclualmm In the re,ion are seasonal. Water leveb: risc in lhe 
rainy KUOn allll fall dUring the dry season. The lopography hl~ a i!feal Infiuencc on 
the depth 10 lop of aquifer in I~ an-;I In the "alleys and .reas adjac:ent to water 
bodies. the aquifer depth may be ncar the laoo surface. On the Oal landl. the aquifer 
der!!' Jenerally range from a rew meters to tens of ntclers ~nellh Iht surfa~'c 
IJowtwer on IlIlhlupcs. the aquirer may be at consMJerlbly ,real deJllh ... In ).!('ncral 
Ihtlkplb IVlhctoporthcpruduc,iwe: a4Ulrer follows and repIKol.esthc: loposraphy 
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(icner.llly. COlnp3f1nJ;!. Ihe nlllnher uf obscrvatlull boreholes Itl prucJuctiun 
hurchulcs In [he: re~iun, the rc1:uively small number ~)f ohservation boreholes is nnl 
enough fOf any groundwaler momlonn!!: due 10 the fairly complex nalure III the 
geology even on I local 54.:ale Moreover. the u~ of one borehole to serve as a 
production well and an ob~rvatiun well in ",nile l"Ommunitie" , .. un~ujlJ.ble 
The oomberofpcofl'c per borehole has increasedt:uIISlt.lcrably infhcfla. . I and 
more willer IS abStral:lctJ lrom the burehules each day 1Il3klllj! it diffICult for the water 
demand!> to be lTlel mthe u:giull cspecially durin, Ihcl.ll)' seasons 
The prescnt stud)' uklk"lcs thai the hydrogeological rclal10nslup bel ween 
monitoring and production boreholes is fairly strong when lhey occur in silmlar 
geologic envirorunenlS and when the: distance between (he prnductUlIl and monitoring 
boreholes are short. The IctpOgraphy also ill:counlS for II~ representativeness of 
munltorin, wells in Ihe stUtly area. 
I:urther, indll:alllllU however show dl:lll. II is doubtful whether any meaninsful 
reiallonsillp between mUl1lltlflll~ and flrutiuction boreholes which are JocalN falll)C1' 
.. part from each ocher (ahoot 400 In and above from each otht!r can be cSlablishc:4.I), 
asnnCcd in abouccighcy pcn.:cmutthc 1lI0rlllorlOgb"rc:holcsandprut.luctlonboreholrs 
I'hisamoun1S fo vII1ually IIUle or no effective: [i!foundwIlCr mOnitoring netwot1c 
III 11M.' Ir:~ton 111 terml uf IMJl1'Ienc 3bundanc:c aOLl the ~palial lIistribution or the 
n'C' I,Huhlc h~'urauhl: Charal.:lcrl<:lh. . \ O'Cl ~h(ln di"ance~ ackl aquifer 
1 : ;, I·:r'·I'<· Iw.:rl~ III the n:Jion mates monllonnl! nOI In tht- immediare 11. .. llIIlle .. ,,1 
,'I'''I.'r~.III''" borehoks ,·cr.· limiled and Interference between aqulter, IS C1111l1ll1l!iC\J duc 
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In Ihe OIbseoceufenough luoos, then the production boreholes can be used IS 
IUtlllllonng boreholes, but coniinUOUS waler level measuremclIIS need In be laken 
'The distances betwct'll moniloring aoo pr<xluclion boreholes surroundinll 
shook! 1l(J( elu,:ccd 400 m bastd (111 the fact Ihallhc aquifers 10 Ihe SIWY area arl' 
loclliscdandhclerogeneousinn:llurc l 'heellvironmcllli5dc5lroYI.."tiasarc5ullof 
hU5h·bumin~ and felling of Ircc5 in the region. Thuse praclict's .neel Ihe rainfall 
pallcrnand give flliC 10 high rales ofevapotranspirdllull hence reducinglhe recharge 
proce:t<:cS. Therctulc educallonal ~all1ralgns and laws should be pHllllul~aled 5(.1 thai 
Ihc~ rr"~lkese.n bemlOilUllcJ 
Redevelopment {If Ihe boreholes by air·lining has bten suggested as the only 
ren.oo)· tulacklelhelssueufreduccJborehnle)'lcldsinlhercglull. I>uringlhc: 
project. pcrtod;c rtdevelopmem of the boreholes was rccomment.led as part of the 
mainten:lnce operatiuns. However. lillie alieni ion W3\ ~ivell to this pert ur Ihe 
main(cnara:c rru~taml1lC' aoo ha~ Ic\ulted in the iK:t::umulallon of miea in Ih\" boreholes 
FilL"lIy. Ihere IsthenceJ 10 ensure Ihal there iSlnimprovemcnt in Ihcdala 
proceSSI",. archiving and diucminatlon of all hyurogeoloekal and hydrologICal dala, 
since ,rouoowater mrormalion in lhe region i1> inadequate . Govenuncnlal and non-
govcmm(lltal orgOlnir.allom m\'oh'cd in groundwaler studies in the region shook! co. 
urdinate Iheir uperalions OInd activili(.~ m order 10 provMie a b3"5 for the dcvelopmenl 
nf gruundwlLtrsupplies inlhc: re,!!:lOn 
AHcrnalC w. . ler supplies such as ram ""'iller h,U\'C\IIII~ 'IhoukJ be provided 
paniadarly in placn which are hydlUleolog~3l1y lIn'ilHlUrable (or groundwucr . 
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Ajayi. O. (1987) Geohydrology or bascment complex rocles of ()oon Slate 
(Workingpaper)p20 
Akili. T.T. (J976) : Geochemical ant.! isotopic studies 01 ,roundwaler In thc 
Up"er Rel!iull. Ghan3. UIIJlubhshct.! Ph .D 'nlfSis : University or Paris. 
Laboratoire d'l-Iydrologic 1:1 de Gcochcme Isotopique. 23lpp 
Akili. T.T. (1980): Nitrate levels in some granilt aquifers (rom Ghana 
In""UIIOM! SymllmjuIIJ IAH Prague CZq:bm!Ov3kja 1982 Impact IIf 
AkiwUllli, 1'.'\. (19Y4J J{ctluclO~ l:OSI of momrorin~ lltlu. . ~,.h III lkvc:lopin, 
wttntnes by collection and analy5i..~ or pre·cx-islins hytlrogeolo,ical dala 
UlIIlllt'l'Inan, R.R . ,uk.! Ayibol('le, N.H. (984) : Some cmil:al issuc! wilh 
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Ballnerman. R.R. (J99t.l) A rev Ie ....'  of water supply sillullon III till: UPIXOI 
RcglonsofGhan;r Final repon. 63p. 
nanoclIg-Yakubo, O.K. (1989) Octurrcllce of groundwaler in basement 
,"uUljJle,; rocks of the Upper Regions of Ghana M.Sc ThesIs. Ollafel11i-
Awolowo Unrver!<llly , Geology Departmcnt, 187p 
IIc'tsoles. H. (1977) : Geologie de I'Afrique . Lt: craton oucSI ·Alri,alll . ~ 
I.1cJ{CKiUchcs Get)h)!nuue,,_cU~ll"I!!-:ttL Paris. 88. 402p 
DeslOn', T.T. (l9H7) I he cxlent , characteristics and rechilril: r;ondiltolU of 
gruurKIwllcr in crystalline ba~lIIclII rocks In Aumalia . Pmceed;"" qf IIU; 
UIUKhcnk. W.N. (1963, : 1)clclnlllllll~ well cfficlcocy hy mulliple sicr 
urilwdm.nlcsb Il.!.l.£.W.tJ..W!ijll A:.:.tI\;WlOoofScu:O!lfu; HyJrul(,¥y lkrkeley. 
EXlracl(lf PublK-alton Nc) , 64, 16p 
t.:'alladian Inlernational De,,~loplllenl Agenq (CIl)A). (1976) , Ghana. 
Upper KC~It!II\ .... otlcr supply prOjCCl . Prehmllla.) t,:.JlIIlIlcnlJ 00 ,roondwalcr 
availability III Ihe ( 'ppc:r RqIUO. Prrpared by W.L. Wardrop and ASIOCI-atcio 
LId . l9p. 
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t:slladiall IlIlernOilional De\'t~lopm(,lIt J\~elK)' (CIOM and ljh .. na Water 
alllJ SC:IIl'r;I~e Corpuration 1(j"'SC). (1978) Effect tin Jroundwalcr Icvch 
"f 11.1111..1 pump \1'1,:11 pn't!ram. A report prC'pOlrcd by \'I .L Willump and 
Associales for GWSC and CIDA. J6p 
C:madiall IIItcruOItiun31 UC\'cloprncnt Agency (t.'IUA) and Ghana Waler 
.md Sewerage Corpofaliuu (GWSCJ. (1980): Final hydwlcoJogital r:port 
fur drJllill~ program 1974-1979. A reporl prepared by W.L. Wardrop and 
As.o;ociales ror GWSC and CIDA. 73p 
Clliltoa. P.J. and Foster. S.S.D. (1993) Hydrogcologlcalcharaclemalloll 
;II)IJ Willer !>uppJy potential of hasemenl aquirers in trop,cal Arrie.. In. 
~ XXIVt" COllpren lit IAIi AS OSLO 1993 Page 1083. 
1100 
Chilton, P.J. and Smith-Carlngloll, A.h.. (19M") t'har3ClcriSCics of 
hakmenlaqulfcr! In Milia"", in relalion to rural waler .'Iuprlic' ~ 
A!!S9Cialjoo nf Hydro1wriCJ' Sqrofe. 57-72p 
('oopl'l'. H.H. Jr. and Jacob C.E. (1946) : A i'!cncralised JI'Ipluur mc1hod 
1m evaJwlm)! fnlJlI;JIIOIn l:umUnI, and ~umm.ri'ml well.fleld hl5lory. 
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l>an;('I. C.C. (1990) Evaluation o( site-sel~tion cntena. well design. 
monitoring lechnitjoes and CO$[ analysis (or a i!roundwaler supply in Piedmont 
t:rystalline rocks. Nmlh Cawlina. U.S. Geological Survey. J5p 
Dickson. I\.D. ;lOd DClilieh. G. (1988, t\ New ([cul!taphy or Ghana. 
mctrkatoo oollion. Longman Group. IMp 
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