PROJECT REVIEW JUNE 1977 - JULY 19'78 1978 -...
Transcript of PROJECT REVIEW JUNE 1977 - JULY 19'78 1978 -...
G310 Record No. 5 August 1978
PROJECT REVIEW
JUNE 1977 - JULY 19'78
1978 - 1980
1. Staff
2. Diary of Main l:.'vents
). .project Outline
4. ~xecution of the .Projeot
4.1 .pre-project .Phase
4,2 .Project .Phase 1
5. I:aroo trroundwater S'valuation .Programme
5. 1 Background
5.2 Kweneng Study Hlock
:;.) . Aquifer itechurge Research in the Kweneng Block
5.4 Serowe Block
6. '[illage \Inter-SupDl" Borehole l"ollutio"
? ;,;valuution of the .:ransvaol .. qui:drs \),)tween traboro{.,o ,"':<1
Lobatse
8. Assessment of .Progress
8.1 .pre-n-oject
8.2 .Project Study .Programmes
8.) treophysics
8.4 Contract Drilling
8.5 Speci.al Studies
9. Transport and ~quipment
10, ~'inance
11. Reporting
1U'J:'I£'WIX 1
2
Study .Programmes - Financial ::!ummaries
33L Drilling 3uIl1lllaries
1. STAF}'
GS10 - EV tl.LU"rWN OF UNDERGROUND. XftR RBGOURC :';3
l'ROJl:;G'r REVIEW JUNE 1977 TO JULY 1978
(a) Team Leader: ~!. J. Jones OJ}! TOO Contract. Took over from
S. S. D. Foster (IGS Seoondment) on the 6th December 1977.
(b) Hydrogeologist: J. L. Farr IGS Secondment to O~~ arrived
in Botswana May 1976, returned from home leave 19th
August 1978.
(c) ASsistant Hydrogeologist: J. H. Baron (nee ·,Ihitelaw) UJ»l
'reo Contract, arrived in llotswana in October 1976.
(d) Assistant Hydroge01ogiat: C. S. Cheney IGS Secondment to
OJ)v" arrived in Bots,Tans in J)ecember 1976.
2, DIARY OF "'Am aVENTS
2.1 Fre-Project
uctober 1974
6 June 1975
1 July 1975
16 February 1976
2,2 G310 Project
J..3Y 1')'16
3eptember-Uctober 1976
October 1976
October 1')76
November 1976
ilecember 1976
January 1977
Harch 1977
April-Hay 1977
May 1977
Dr. E. Y. Wright visits Botswana and
prepares GS10 project proposals -
these submitted December 1974.
Yroject !'lemorandum finalized.
Yre-project phase 1 of GS10 initiated
by GS
UK Government release Capital Funds
S. S. j) • ..'oster visits "roject
Report ;'ID/03/76/16 (G.JIO/l) issued
"The Hole of Hydrogeolo:G" in ';Iater
Resources ~lanning.
J. H. Baron lAssista~t dy~rogeo1ogist)
to Botswana.
I). S. Cheney lAssist"'lt iIydro
geologist) to botswa."la.
GSIO Bedford J5 truck arrives.
Bulk of equipment arrives.
Geophysical Surveys in Kweneng stllrted.
S. S. D. Foster visits project.
S. S. D. Foster presents draft Field
V/ork and :)rilling .Progrwma for
1977-78.
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June-July 1977
21 August 1977
September-October 1977
7 October 1977
October-Nov8nber 1977
October 1977
December 1977
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S. 3. D. Foster presents 1st Arillual
Report of .Project Leader to OJl.I
Report YID/OS/76/16 re-issued as GSIO/1
Work started on report GSlO/2.
All GSlO vehicles in Botswana
Seismograph Services Ltd. (SSL)
Drillinl' Gont ract st drted.
S. 3 . .0. li10ster visits project.
Rodio Drilling Contract started.
Dr. A, Bath (IUS) visits GS10 for
Special Infiltration ".nd .pollution
Studies,
Report ~SlO/2 issued "Co!'l\1ilation
of. Ground ""ter Hap - l>xoerience in
the Use of llata on the GS Rorehole
Archive"
S. S. U. Foster visitn project.
Change in team leaders on 6th.
r~. J. Jones took over fro!:) Er. o'oster.
Dr, D • .P. ',{right, hydroeeolo<!l.cal
advisor to O]]'!, accomuanied Mr. Jones
for the handover period and to
discuss and assess the pro.p,'ress of
the proj ect.
SSL on standby all of December.
Rodio ~rilling contr~ct completed
on the 16th. GSIO Test pum" "nit
ordered.
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January 1978
Harch 1978
April 1978
l·fay 1978
June 1972
July 1978
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SSL resume drilling in Kweneng.
~roject proposals for 1978-80 submitted
and discussed. Draft of report
GSIO/4 completed. 33L finish drilling
in Kweneng. GSIO Test Pump unit
delivered on the 7th: Test pumping
started on the 13th.
SS1 on standby.
Work started on the 'l'ransvaal aquifers.
Test pumping at t'HO si ~_:es in Kweneng.
SSL resume drillinp: in Serowe Block.
Geophysical survey in Sero'"e Block
started. J. Farr starts home leave.
GS1l, Record La. 1. ":;W1JJl",:r of SSL
drilling in Kwenene" anJ Record Ko. 2
11:1 lfrouud"'ater Inve'ltor't feY' the
Kweneng 510ck lt com;;lGted.
SSL drilJ.in" in J<lrowe com:,leted.
1978-00 ~ro,iect ~ro0ramI,e finalized.
i'roject Review prep2.red.
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3. J:'ROJECT OUTLDiE
3.1 The stated main objectives of the project are a total
national underground >later resources evaluation and
compilation of an inventor,r of predicted available reserves
for future planning,
3.2 Broadly the plan of operation was:
3.2.1 Pre-Project J:'hase - data collection, compilation and appraisal
of available information by GS counter
part staff. This work started in July
1975 and was closed by GS in September -
October 1976 with the on-going \fork handed
over to ~SlO 'reo staff.
3.2.2 Ph;;.se I - dei.'ining and delineation of hl:-lin ground
water occurrenceu/aquifers
- initistinc detailed grounawater data
collection for these main occurrences and
aquifers
- defining nnd i!litiating inveEtigntions
aimed at establishing ground water
developments 8J1G. resources evaluation for
these main occurrences and aquifers.
- 3pecific studies a.nd quantative evelu"tions
based on the results of J:'h,qae I.
4.1 rre-J:'ro,iect J:'h:cSe: July 1':75 - June 1976
'rhis pL:.3.0.'">e waS surnr,~Arized by J. Farr in his prelu:ir:'-lr;'
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report dated 30 June 1976. This report pointed out the
difficulties in locating and fixing data points and the
patchy distribution and collection of data, as well as
the inherent inadequacies in the quality of the data
available. In general, however, considerable effort waS put
into this du.ta collection.
4.2 l'roject Phase 1
4.2.1 '£his is considered to have started "'ith J. f'arr's arrival in
Botswana 'in Hay 1976. In his preliminarJ report, he outlined
a possible plonning approQch to l'h',se I - "Although the LiS10
.Project is El national groundwater resources study it is
considered that the most feasible approach to this ultillate
aim is to select for ill.vesti:3'ation relatively SI.lP,ll "reas which
encompass Botswana's potentIally most important aquifers and
Vlhich will include aspects of the hydrogeoloGical cyole «hie-I]
«o.rrant special study." During S. ,'oater's visit to Botswanp.
(September - October 1976) J. Warr's planning approach was
fonnalized and presented in the Report ;m/OS/76/16 (G310/1).
1'his Was accepted by the Botswana :;0vernment. '£11'0 areas were
selected for study, 3erowe (Central District) and Letlil1'..keng -
(Kweneng Vistrict).
4.2.2 At the beginning of the period under review, 'fork hnd started,
or was about to start on the follo«ing progr=es.
(i) gV2.1uat ion of the Karoo Aquifer .Properties in the
K'leneng Study Block
(ii) i!1valuation of the Karoo Aquifer ~roperties in the
Jerowe Study Block
(Hi) Aquifer Recharge Research in the Kweneng Jtuuy 'llock
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STAGE
;onnberg LSalt
lve Sandstone
'ansition tds
ld Beds
,per Bcca ,ncludes 'aufort Beds)
.ddle Ecca
wer ~cca
yka
'rABL~ 1 THB KARO() SIST J!lII
L I'l'H ()L()GY
Fresh and weathered basalts and dolerites,
Aeolian sandstone. Strong cross bedding
1\eolian and water born sediments, red and grey sandstones, siltstones and mudstones.
Red marls, silts tones and mudstones
.Predominantly carbonaceous mudstones and. coals 0
Arkose3, Grits ana su bordinate shales and coals.
Garbonaceous mudstO[leS and shales.
~illites, mudstoneo ana shales. ~uhor(!inr,te
sandstones and limestones.
HYDROGEOLOGY
Locally poor to fair aquifer. Limited groundwater occurrences, ~'issured aquifer,
Good Aquifer, high fissure porosity, some intergranular porosity.
Generally poor, occasionally fair aquifer horizons.
Very poor penneability -Aquiclude.
Very poor pe:rmeability -Aquiclude.
Very good aquifer horizons in nrkoses and grits, high fissure porosity and permeability, fair intergranular porosity.
.Poor pereeabili ty -,~qu i cluCle.
,tIoor permeability -1\0uiclude. Sands tones and limestones occasionally fair aquifers.
ST()HNB'sRG
SBRIElS
D"tfY.KA ~,rD
d0t.:A ;j~Rl~~
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(iv) Village iiater Supply Borehole l'ollution - Mochudi
Township.
4.2.3 In November 1977, an additional programme started in the south
west of the Kweneng Block to appraise the prospects of
establishing a groundwater supply for the Jwaneng Diamond
Mine. 'l'his work is to be the subject of the GSlO lteport No. 5.
"An appraisal of the Groundwater l{esources of the ciooa Series
in Central K'1eneng in Relation to the Jwaneng Diamond-I'line
lJevelopment" •
4.2.4 In April 197e, the reoonnaissance work started as the
evaluation of the 'Eransvaal Aquifers between Gaborone and
Lobatse. 'i'his study is considered to be the first of the
project ph8.se IX programmes.
5.1 Background
Rocks of the Karoo :'yste;n underlie about 50, c· of Botswal1p .•
Il1hey occupy tivo large basins, the main basin covers the whole
of the centr!il and south weste:cn Kalahari. '"'he smaller,
north eastern basin is the western extension into i.;otSWal1& of
the '.Ianki Basin. In both basins the Karoo System is overlain
by varying thicknesses of the geologically younger Kalp.h~ri
Beds. l'he m<lin stratigraphic .sub-divisions of the lbroo
.3ystem a'1d their hydrogeolomr nre given in {l'able 1. '.rhe two
well developed sandstone stages, the Niddle Bcea and the Cave
Sandstone'3t!l€es are areally the most extensive. and in teres
of resources, the most important aquifers in Botswana.
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5.2 K"eneng Study llloclc
5.2.1 The stUdy block of some 11,000 km2 is centred on Letlhnkeng
{240 05 South, 25°01 East) in Kweneng District. J, Baron
t1"roject Assistant Hydrogeologist) started work in the area
in October 1976 and had completed the data collection a~d
field verification for the block by June 1977. 'l'he initial
compilations of the data on maps had been completed IUld
reported on iW ;,eptember 1977 (Report GSIO/2).
5,2,2
5.2.4
From ~:urch to July 1977, R. l:'eart (GS Ceophysicist) carried
out extensive surface geophysics aCross Hr8:lS in the northern
pe.rt of the block cons idered to be ttnderl.oi" by the Cave
SD.1lcistonc (Cnd Stormberg Basalt. lIe did 110 :,," of IJa,gnetic
tr,werses ',.na 64 vertical electrical soundin(;u. ,;hile the
results in determining- the depth to the Cave Sandstone -
:0~.salt contact Here not concluGiv8, he rTas able to Qutli!1e the
subcrop of the BaG"lt.
BGtween j,jarch 1977 a~Cl l:ovember 1977, a fjr;r. of consultaYcts,
Wellfield COilsultinC Services Ltd., -"ere e!'Jployed by :.'Wlo
,illlerica.'1 to conduct a rapid hydrogeo10is'ic:ll eV'lluation of the
t:cca Aquifers in south of the block. We11field 3ervicerl,
using the drilling contractors t..ardwnter, constructed 27
trial proQuclion and observation boreholes during the, poriod
July - September 1977.
In ha,y 1977, (;,310 had provisiollally identified 10 to 12
sites ill the block for detailed investigation. It "as
planned to use contre.dors to drill cored observ:otion bore
holes besides existing pumping wells ,wd to run well controlled
pumping te,3ts at each of the si tcs. S3!Jlples of the cores ".rere
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to be sent to IuS, London, for laboratory testing. In addition
to the geophysical borehole logginc', it viaS proposed th~t flow
logging shoul~ be used during the pumping tests.
5.2.5 During July and August 1977, R. <'eart m!).de further detailed
resistivi ty and magnetic investigations at 6 of the selected
test sites with the aim of establishint; whether the sites \~ere
typical or ,'~nOIf]Hlous~ One ~.;j.teJ Jale.ji-le t proved o.:r.onalmls
Q...Ylu \vaS dropped from the d~illin,o- profjrAl:lDle: l1he .site iias
situated on a fa1.,;.l1; 7.one"
le-..:tiJ1g of tly) main core drillirlC contrac~; to Geisr."!of;;rsph
::.iervicos \lfi!J Ltd (.s0j~) too,].;: from ti.pril to f';id .',.l.l:-u;:':; 1'~!7'7.
L::.bo:;:,.·";.i:o:ry dc.'termin-'.tion:') of verticD.l permeabilit.' to be L<1(lQe.
5.2. '7
J.:l..n1J.£u::;r to Hr..reIl 197;;;, SSL drilled 2U bore:"lOles iE tl:e
.f;.;.G hloc .... ~o :. tot'!J elf 11 ob:.;erv~ Lio,.'_ bore:lolcs :.,81'0 drilled
ll.',' ••••
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A group of 3 boreholes was drilled ut the Lothate .hm as part
of the rech.2rb'$ reseaT'cho Drilling nt two sites 't,TaS abandoned
8.S being unpI'oductive. The remaining 6 cored observation
boreholes were drilled at Wellfield Services test sites in the
south of the block. In part, these latter holes "ere drilled
for the addition",l proeramme to appraise the potential
groundwater supply for the Jwaneng Diamond ~1ine. A f\tll
summn.ry of the S3L drillinr; in Kweneng has been prepared by J. 3arv"
(;}::;1O ll.ecord Ho. 1).
5.2.8 '!'h8 project ",,3 unable to find a contracto:' to undertJV:8 t],c
pll'npirlr; test proersmme so JSL 1iiere reque:.::ted t,; d.o the l'iorK.
'llhe project ordered a test pumr ulli t froT1 J.'iono .hm:~s ir, lat(,;
November 1977, ex~~ecti!-lf; delivery ill early J;-,nu.o.r: I~he test
"roved full tJ.
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ilpril 1978. 'l'he pum!' 1<£,S ~hut uown on the 15tfj .\pril and the
water level recovery .... laZ fleLSured for 14 (;.a;;.:!-. The pUIT!r waS
then install~" in the test hole ;;20 using shear lec;s and a
chain block. R five day pumpinc test at this site was started
on the 20th April. On completion of the test, the pump once
again fell doml the hole. A close inspection of tl18 pump
drive head showed considerable over-sized thrends in the
pum~;) body where t:18 rising :i:.ain screws in~ 'the suppliers,
Nono ~uups ~"1.frica LiJ:jlitea, \-TOre iInr!lediately cOLt-3.ci.ed.. I~iono
2.ereecl to l'e:.~lace !'ill the lost items of e ::liprh3n+,; ~!l."l 0.1flO to
droppe'~ down n~B }101e durinG Bureh. li.t the ~ir~e of the visit
to NOllO, &'1 uUuitional set of·65 ron l~iGinP'" nl8.in a...'1I':" ~J.rive heD-d.
Here ordered to enClble the J:'roject to test the "!.1aller
replaCeIOlent PUI"P uld parts were delivered at the end of June.
In the mSicltime, ;iater .lffairs h"ve been CO'lt<lcted to help
fish the pUJllP out 0 f r. 20.
5.2011 '';:he a."flcillary work on the aquifer determin:).tions at the
Wellfiela Jervice.s f5ites, the luborator'J core measuren8nts
end the {)oreholc lor;eine progr8lllIDe, hQve been largely completed
a.'10 the results nre to be incorpor,:ted in the Re;:;ort "::l10/5.
lJue to the small cliamet ers of the pumped boreholes, it was not
possible to flow Md teLlp8r<1ture log them under dynr:rnic
conai tions &s 11 ·'.d oriGinally been "roposed. JJepending on the
verticali ty, a l:1iClimum borehole di8l'leter of 225 1;}B will be
required to accommodate the logginC tools ,"nd the 65 mm pump
ris ing main 0
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5.2.12 None of the planned pumping tests, or ancillary works, at the
other test sites in the Klfeneng Block have yet. started. ~he
test programme is scheduled to restart in early 1979.
5.2.13 In April - May 1978, a re-evaluation of the borehole data
WaS undertaken and reported on - GSlO Record No. 2 "A Ground
water Inventory of the GSIO Kweneng Study Block". Work on
this GSIO Record showed there to be a most pressing need to
reorganize the Survey groundwater archive. A step towards
this ~10uld be a standardized form of data collection a'1d
storage.
5.3 Aquifer RecharGe Research in the Kweneng Block
5.3.1 The aim of the (;310 recharge work in Kweneng Was to identify
whether deep diffuse recharge has taken place in the recent
past. ~he method used WaS to establiSh; (a) profiles of the
unsaturated zone (moisture content and grain size distribution);
and (b) the chemical and isotopic composition of waters in
the unsaturated zone and the first-strike water at tr.e top of
the saturated zor:8. Later work i'1Volved hydraulic rleasure
ments on re-packed sDmples.
5.3.2 Between ~;ay and October 1977, a nobile laboratory Was built and
equipped for use on recharge and pollution studies at a cost
to the project of ~12,OOO. ~quipment includes a 3KVA ge~erator,
piped water, a ~iSL 2L centrifuge for sample extraction, and
apparatus for the full chemical analysis of water.
5.3.3 The chemical and physical analysis work was supervised by
J. Lewis (Survey Chemist) between October 1977 and June 1978.
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~r. A' Bath (IGS Hydrochemist), under a special studies contract,
visited the projeot during Uotober and November 1977 to establish
handling and analytical techniques for the samples frem the
recharge drilling programme.
5.3.4 Three sites were selected for the recharge workl-
(i) lilakojwG - sampling sites were selected across a
major fossil valley.
(ii) Khudumelapye - sampling sites were selected in the
bottom of the shallo;; Hosha"eng valley near existing,
12 to 18 metre deep. hand-dug wells.
(iii) Lekotsana - sa~pling sites were selected across an
area of open plain.
Water table or semi-confined groundwater conditions were
considered to exist at each of the sites.
5.3,5 'l'he sampling programme at the sites called for dry :lUgering of
top sands, air core or air hammer drilling of the calcretes,
and air flush drilling in the bedrock to the first water strike.
2he recharte urilline WaG carried out under contr(:ct by Radio
;3A Ltd. Rodio used a "l'iobile" rig'lnd the required arilling
teclmique3 ~ iiodio I $ progress picked up after :1 doubtful
start. 'l'he avera.f!e drillin, cost waS R47.4'/ per metre.
5.3.6 i'he results of the 1977 rechrlrge results are currently baim;
>lritten-up and the l(eport USIO/6 "lhe Likelihooct of Recent
IJrounct1'later i{echarge in the halahari - A GUf:imary of Research
1':178.
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5.4 Serowe Block
5,4.1 ~
'l'he study block covers some 7,5UO km of the Karoo outcrop around
Sero~le (220 22+" South, 260 42t" l!;ast). C. IJheney (<-roject
Assistant Hydrogeologist) started the data collection and
field verification for the block in late 1976 and had completed
the bulk of the l'lOrk by August 1977. AdC1i tional field date.
"as collected between 11ay tllld July 1978 coinciding with the
drilling programme. ,'lark is currently in progress on the
com)ilr,tion of the data on to maps.
5.4.2 ;oor the core drillinc programlle, it waS C1eciC1ed to concentrate
on the Cave Sondstone "Iater occurrences to the north and west
of Serowe rather than on the Ecca 3eries to the south 'lnd east
of 3ero;'If:. This decision l'inS based on the facts t').9.t (a) this
,"Cca outcrop WaS not ty?ical of the bulk of the Karoo in Botsl;ana,
b) the ~1'eological structure 1'{aS not favourable for 8. use:;-:\ll
groundwater occurrence a'ld (c) previous drilling results showed
poor, er!'3tic borehole yields I>i th often, poor water quality.
5.4 .. 3 'l'he selection of the U8,YC Sandstone drilling sites 1"as b .. ')sed
on detailed surface '~eophysic" aimed at looatimt the l'1ajor
tectonic features of the area. Evidence from j"St north of
the block would indic.~te that these tectonic features control
the groundwater occurrence ",]la flow of the area.
5.4.4 Betlfeen ray and ,July 1978, R. Peart (GS Geophysicist) carried
out intensive Clagnetometer and surface resistivity surveys.
Coupled with the aeromagnetic maps, these surveys establis]'
r>ajor fault zones, c'xeaS of deep or shallow, thin basalts,
areas of deep or .shalloN p thic:·~ basal ts, <.wet Ilrer;t·; -.. li th no
basalt cover. Also between !'''",f an<i J'-11y, 6 of the ~SlO
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drilled boreholes were geophysioally logged to assist with
t'he interp:t'etaticih of the surface geophysid8. Curr!inti,ythe
results of t.he surfaoe geophysics and bcrehole geophysios are
being interpreted and oompiled into a GSlO report.
5.4.5 In addition to the above geophysics, H. Nickel (West GeDnan
Aid) also undertook a 2 week investigation in the area using
a modification of the Enslin electromagnetic method. These
investigations produced no useful hydrogeological information.
5.4.6 The Seismograph Services drilling in the block started on the
1st Nay 1978 and finished on the 21st July 1978. 7 cored holes
were drilled totalling 1002 metres. The first hole Cl,
penetrated 55 metres of unconsolidated sands, Cave Sandstone
between 55 and 73 metres and Transition Beds between 73 and
124 metres (total depth). 'l'his drilling result confirmed the
aerom.'3.gIletic interpretation which indicates a su bstantial
subcrcp of the Cave Sandstone with no overlying oasalt cover.
Surface magnetic traverses showed this subcrop to have well
defined faulted margins.
5.4.7 A summary of the other drilling results is:- Hole C2, drilled
some 20 km west of Cl, Kalahari Beds 0 - 28 metres, Basalt 28 -
142 metres, Cave Sandstone 142 - 229 metres and Transition
Beds 229 to total depth of 251 metres. Hole C3, drilled some
9 km west of Cl, Kalahari Beds 0 - 60 metres, Transition Beds
60 to total depth of 88 metres. Hole C6, drilled 1.8 km west
of C3 on the other side of aN - S fault, Kalahari Beds 0 -
43 metres, Basalt 43 - 75 Betres, Cave Sandstone 75 - 100 metres
and Transition Beds lUO to total depth of 155 Betres. Holp. C4.
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drilled 3.2 km nortl] of C2, was abandoned while drilling in
very broken calcretes of the Kalahari Beds at 24 metres.
Hole C5, was drilled at 2.8 km north of C2, Kalahari Beds 0 -
38 metres, Basalt 38 - 92 metres, Cave Sandstone 92 - 184
metres, Transition Beds 184 - 190 metres, Dolerite Sill or
dyke 190 - 201 metres. The latter was extremely sheared.
Hole C7 was drilled 14.5 km south of Cl, Kalahari Beds 0 - 49.5
metres, Basalt 49.5 metres to total depth of 158.6 metres.
Work on this hole was suspended as the SSL contract period
had finished.
5.4.9 While it had originally been plCillned to construct several
production holes during this drilling progrrurune, this lVas not
possible das to the lack of time and the type of drilling
equipment being used.
5.4.10 Currently reports are being prepared on the hydro('eological
reconnaissance work, the surfsce and borehole geophysical
surveys and the results of the SSL drilline.
6. VILLA;;;'; ""TER SUl'PLY BOR3fWL~ POLLU'l'ION - Ec'GRUDI TOWN3Rlt'
6.1 J:'revious work by Survey chemists established very high
levels of nitrate in many village Hnter supply boreboles in
Eastern Botswana. In).fay 1977, GSlO, in collaboration lVith
the Survey, proposed u limited pilot investi'!:ltion into the
factors cop trolling the accummulation and movement of
pollu ta.'1ts in the Ulls(,turated and saturated zones around two
vlater supply llorellOles in. r'~ochudi.
6,.,2 {rhe investiGations were su')crvised by Jo LeKis (GS Chemist)
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and took place in October 1977 and January - February 1978,
'Chey called for soil and bedrock sampling at 0.5 metre
intervals a.'1d chemical analyses of the pore waters, in
particrular for the nitrate and chloride contents. From these
results, profiles of the grain size distribution, water
content and nitrate/ohlorides concentrations were completed.
'l'he drill samples were analysed in the field using the mobile
laboratory •
6· " ,;; lJuring October 1977. Rodio drilled 5 test holes totalling
'122 metres at the 2 test sites. The cost of the drilling, •
including l"",terials WaS approximatelY 1'5500 or 1'45 per metre.
6.4 'rhe ,(odio drilled test holes I,ere temperature and
co",ductivity logged after completio;1 and again in J81lU,3ry and
Februar~r" Depth salnples were also taken and at!.alysed. ' ... 1-";0
pumping t80t8 V'ere run at the \,~D.ter ,,:>upply borehole lOH3 du.ring
}'obrual'Y 19'18. Lithium chloride WaS used to dose a ncr:rby
source of pollution to trace anu time the moYc;]E:;}t of r:ossible
pollutant nO>1 to the borehole.
6.? The field Iwrk for the pollution study 'laS completed in
l'ebruaI"J 197(? 'The draft of Repol"t (;310/4 'IRS prep,ued by
J. 1ewis and 'Ias sent to London fol" editing. ',,'he rerv1·t is
nOIf ready for issuing in August 1978.
7, EVALUATION 01' THE TRANSVAAL AQUIF1i:RS - O;,BORC:§fl,OBA'fS2
7.1 'l'he objecti.ve of these inventigations is to evalu"te
the possibility of using groundwater from the Illr[~nsvanl
Aquifers to augment the (;abol"one - Lobatse "iater supply.
1'0/ .. 0 ,.. 0
- 18 -
7.2 L'reliminary work on collecting and compiling the data for
this study started in April 1978 under the supervision of
J. Baron. Currently, work is progressing on the preparation
of the barehole inventories for four 1: 50 000 map sheets
(2425D3, 2425D4, 2425Bl and 2525B2! covering the Transvaal
"ystem between !;abarone and Lobatse. In addition, a borehole
inventory has been compiled for the liaterberg outcrops of the
'fhamaga Area.
7.3 While it is not yet possible to define the progrsmme in
detail, the main groundwater proopects are considered to be
the outcrops of the karstic 'rr:msvaal Dolomites around
jtamotswa (about 12 km2), Bathoen (8 km2 ) and northern Lobatse
(16 km2 ). It is hoped to establish the groundwater regime
and resources for each outcrop, and to evaluate their ground-
water supply potential. ·lIvidence and abstraction records
2 from the Lobatse outcrop area (about 5 km ) show that the
aquifers have a fair storage capacity and that they receive
certain amounts of annual recharge.
7.4 In addition to the study of the Transvaal dolomites,
attention will be given to the groundwater occurrence in the
Waterberg outcrops around 'l'hamaga and Otse. It is hoped
that a programne of monitoring s·pring flows in these areas
Vlill give useful information on groundwater recharge and
storage Vlithin the Waterberg System.
8, 1 Pre-Pro,j ect Phase
While the project team have had mixed feelinw, on the value of
re-working and re-evaluating the grou.ndl'Tater data cont"ined in
J 9/ .. ~.
- 19 -
the Survey archive, there is general agreement that the archive
needs to be rapidly re-organized with the data being .classified
and stored under degree sheet numbers. It has Doleo been agreed
that all data should be listed in a uniform manner suitable for
computerization. '.l'he G510 Record No. 2 "A Ground'''ater Inventory
of the G510 K"leneng Study Block" presents some of the advantages
of such a re-working of the archive. As a result of discussions
of this Record within the Survey and Ministry, it has been
requested tlwt GSIO produce a draft for a manual on standardised
data collection and storage collection in the hydrogeological
, divisiono
8.2 .l;'ro.iect .l;'hase I
8.2.1 Project Study Programmes
(1) J(VTenenz Block: 'l'he first ph9.se of the i;"lO field,;or:'
in the block, the fiela collection eJ1d "orification of
ground1<ater data, h('s bgen succe3sfull~' coropleted by
rr,ay 1977. The seconCl ph.sse of fieldwork Was J.eft
uncompleted in ,lpril 1978 following the interruption
of the pumping test proe-rBJ"no due to tbe loss of the
(;310 Nono test pump dOlffi hole '1120 and tlY0 cor:pletion
of the SSL drilling in the block.
The olltst"ulding ,;ark in the block includes (a) addit-
ional drilling et two sites to complete tb'~ Ca.ve
Sandstone inv8 c,tigations, (b) test pumping at the 8
borehole sites already drilled by GSIO (plus the 2
additional sites, if drilled), (c) oo:rehole fom."Hon
loe-ging of 12 of the (;310 drilled observation bor-eholes
end (d) the fina.l cOf.opilntion of the e;eology ,,-nd
- 20 -
hydrogeology of the area. It is planned to complete t~is
work, other than the new drilling, by the end of Hay 1979.
In May 1978, Wellfield Consulting Services (WCS) started
a detailed evaluation of the Ecca aquifers in the south
western quadrant of the block for the Jwaneng ~line 1vater
Supply. WCS are soheduled to complete their investigat
ions by December 1978 Md their results will be
incorporated in the GSIO appraisal of the whole block,
and the extrapolation out frem the block •
. (ii) Serowe Block: The field collection and verification of
data was completed by the middle of July 1978. Currently
all the available greundwater data are being co~piled
for evaluation. The surface and borehole geophysics he.s
largely been completed and the results are expected to
be interpreted and reported on by mid October 1978. The
outstanding working in the block is the constr~ction and
test pumping of 5 production boreholes and the completion
of one of the cored boreholes (C7) started ~ SSL. It
is planned to complete this work between July and
October 1979.
8.2.3 Aquifer Reoharge Researoh in the Kweneng Block
all the field and laboratory work on this study had been
completed by the end of July 1978. The results are with
S. S. D. Foster who should be producing the report GSIO/6 in
the near future. At present GSIO have no cIeer plans for
follow-up work. Some strong doubts have heen expres"ed over
the value of this particular study in tenns of valid, qu
antit.9.tive results. It is considered that any future recharge
21/ ....
- 21 -
research should be closely intergrated with the work of the
GS Hydrogeology Division.
8.2.4 Village Wate,; SuPPlY Borehola .\'ollution. Mochudi TOlillShip
ThiB study has been very successfully completed end the report
GSlO/4 will be produced by the end of August 1978. The work,
as reported, clearly establishes the presence of nitrate end
other pollutants in the unsaturated and saturated zones around
a supply borehole and this matter is now subject to Government
action.
8.2.5 Evaluation of the Transvaal Aquifers between Gaborone and
Lobatse
Work started on the compilation and field verification of ground
I{ater data in early April 1978. To the end of July 1973,
J. Baron has spent approximately 30 days on this work and a
technical assistant 60 days. The compilation he,,, proceeded
rapidly and was nearly completed by the end of July. With
drilling scheduled to start on 1st September 1978, the draft
final report on this work is expected to be near comnletion in
December 1978.
8.3 GeophYsics
8.3.1 ~urface Geophysics
A counterpart GS Geophysicist (R • .\'eart, IGS Secondment)
has spent two periods working for the project. 'rhe first
period was spent in the Kweneng Block, the second in the
Serowe Block. Due to the lack of a high powered Induced
.\'olarization (1.\') unit, the investigations have been limited
to magnetic profiling and resistivity methods. Tlle "fOrk has
produced disappointingly mixed results. Contrary to many
~/ ....
- 22 -
previous assertions, vertic8.1 electrical soundingn \ ~J.ilJ.()) he.ve
proved V'irtually useless in determining the thiclmes s. of the
Basalt cover overlyinc the Gave Sandstone due to the lack of
a marked resistivity contrast between these formations. This
is particularly true in the Serowe Block where the project
,TOrk has concentrated on the Basalt/Cave SDIldstone ground-
water occurTences~ l1iagnetic profiling, however, has ?r0ved
suitao18 for delineating B:";alt subcrops, hut :·118 inte)'~retations
of these profiles "re pllrely empirical.
.A limite'd investiGation in the 3erowe r31oc~~ lu;ill~1 the 3urvey
Induced J:'olilriz;:.tion unit hils sho\·m the Basn.lt to hc,ve " ve-ry
high chargeability compared 'fith both the Kala.l:ari Beds and
the Gaye Sandstone. Unfortunately the Sur\'ey U' unit develops
insufficient pO>ler to enable it to be used for the deep
soundinGs requirea by the project.
8.3.2 DOl'ehole I/onnation) Logging
'J.'he CS 31ectron.ics i~ng:Lneer 0;;. J.ilnerj hns beer; .'::-tY0.:t.:;".:~l:le to
log certain of the boreholes drilled by the project. Lo'·s
available comprise, 3pontaneous !'otential (SP), Resistance,
Long 2.l1d Short Hormal Resistivity, Natural Uamma, Uamm,,-G=a
porosity, Bulk Density and Caliper. Several deficiencies
exist in the logging data; (a) in the case of electrical logs,
no information is ohtainahle from that portion of the borehole
above the wder table, and (b) that portion of the borehole
which is steel cased only produces attenuated measurements on
all gamma lOGs.
It is proposed that electrical formation 10gEiing could be
obtained above the >later table bY,l'lrchasing an induction logt:;i.'lg
.• 23 -
tool.
8,3.3 In an atte'''pt to coordinate and assist with the interpretation
of the surface geophysics in the Serowe Block, each borehole
Was formation logged immediately after completion, The
interpretation of the surface geophysics llsing these formation
logs showed there to be n. need to estn.blish the electrical
properties of the core samples. It is proposed that a core
teet unit be purchased by the project, ~I.'his llni t "ill
determine the resistivity, the sllsceptibility Illld cho.rgeability
of core samples,
8.3.4 -"roject experience has sllOwn that it would },·,vc been atlvanto.geous
if the team had included a full time geophysicist capable of
conJucU.ng sllrface and borehole surveys: It is felt trois should
be borne in mind for future projects,
8.4 Contract J)rilJing
8.4,1 Core .urilling - Seismograph Services Ltd. \03,,'1) Contract
In three drilling periods, 38L crilled 2949.20 iletres \ 263
metres per month) at a cost of 1'97.53 per metre. :,urnJ'Llries
of the drilling :md costs for the l',weneng a'ld .:iero·"e blocks
are given in Appendix 2. 'l'he contractor's hid1 and
competent performance is cons.idered to have luIly j,,"3tified
the single Elction tender and monthly hire arrarll;ements.
'l'he drilling produced 1936.22 l'tetres of 80 1!JII] diameter core
for the correlation of geophysical formation lOi:S and l,bora
tory physical property deterrninations.
Un the completion of the next three months drilli",,' for the
G-aborone - Lo bats8 Water ':.l'upply investigations, ~f1e e:":r.)haSis
- 24 -
of the f\lture contract drillin<; will be 1'or the constructLln
of abstraction and observation holes using the most economic-
al methods possible. Rapid air hwnmer drilling for example,
is costing around 1'60.00 per metre in Bots1Yana (includinG
casing). '£ho project, h011ever, "QuId like to retain a
capability to core drill certain selected horizons.
8.4.2 Augering. ,tir Hammer and Air Gore j)rillinf, - Itoaio (J.<) Ltd
Uontract
Radio's perfonJlance was satisfactolJ' rut it i:3 unli,,'!ly th",t
the project will require further, similar drillin:': :0,h3
depths involved in this contract (60 m). Should the project
require simile,r, shallower arilling, the SUr'ICY f s rI.)oi:;" .;.'est!l
riG iSaw.J.uately equipped to un1erta;ce the work.
8.5 Speoial Jtudies
rrhe project let 3 3pecial studies contracts in lQ7'l-7E. '.2ho
first two were let to the H~rdrogdological ~)ep.'trtr~".e::d; of tile
Insti tute of ~~eological .)ciences as -!-;he execu ~irl.!; ,~·,t':G!1c/ fOl~
the UK Eational 1~nvironme~1t RezeRrch Council.. ?ne contracJ~s
(ij Bnd (ii) were priced at .P3 200 ,,-~d .P8 000 re3""c':i\'cly.
The third special Gtud~' contract was aw"rded to trle ,:uclear
Physics Research Unit of the UniV81':-:lity of ~-/itwBter3r,:,,~ldo
The contract price Was .PlO 000.
8.5.1 Heasurement of physical properties of borehole core '3u;nnles
'I'he measurements com'prised; bulk density, i~terGra:nul::.~
porosity and permeability determinations on 125 core s;vTIDlen,
and~ in addition for 26 of these samples, cen+::rifuge spec.i "ic
yield deterr'linat.io!lS.
25/ ....
--, ; (/ /'
- 25 -
The results of this work are very informative, 1'hey sho;1 ,lcca
3andstones to have unexpectedly high intergrc)1v.18.r poro:oities,
The results ,,; , to be included in the report G310/5.
i'he project will renew this contract to cover further
determinations on approximately 200 core samples of the C,,\ve
Sandstone from the Serowe Block and possibly, 50 determinations
on samples from the Transvaal aquifer drilling due to start
in September 1978.
8.5.2 Determination of the role of the Kalahari Beds in the Control
and chemical evolution of rechar{;"t
Under this contract, Dr. A. Bath visited the project for 6 weeks
during October and November 1977 to establis" haYJdling and
analytical techniques for the samples from the rech&rfte drillinrr.
He reported on the results of the chemical l:lethodG used in the
investigation.s in December 1977 (Report Ho. ',{U/IJ;}/77 /23,
Ground"'ater Recharge Research i.n 30tswana GSlO PI'oject: Studies
in Central Kweneng usinG' Chemicel Hethods) e ':;:ho results are
to be incorporated in the re;lOrt '.:310/6 whier' i.o under preparation
by S. 3. V .. Poster in London.,
The chemical results of this spede.l study are eYlcollI'aging,
clear chloride peaks were establiShed in the profiles of the
unsaturated ~one of thc Kalahari Beds. Unfortunately, these
results themselves do not prove, Or disprove, whether modern
recharge is taking place,
its a result of ill'. Bnth's visit, memhers of the ,:S Che,,,is:ry
0ection can now undertake the re:{uired analyst'''' necess8.ry to
establiSh and interpret th", 'or,emical/moisture profiles of the
., r:" : 0 •••
- 26 -
unsaturated zone.
8.5.3 Groundwater isotope Studies
This special study comprised; (a) a regional isotope survey,
(h) tritium dating horehole first water struck, and (c)
tritium datine of moisture profiles from unsa.turated zone.
8.5.3 (a) Regional Isotope Survey: ~umped samples from 17 boreholes
. 13 14 in the Kweneng Block \~ere dated USlllg C and 0 (O,rhon
thirteen and fourteen j, and in some ca.ses ~ (tritium).
'rhe 14C concentration results sho>1ed a tendency for
grouping around 55 - 60)·, m. c. \ie. compared with the
modern 12
0 - 140 ratio). '£his concentration "'as
inteZ}Jreted to give an age of between 35C() to 5500 years
before present (BP), assurdne modern recc1e.rre to h".ve an
initial activity of 85~· m. c. 'l'he resu.lt" of the ne dating gave doubt over the validity of this f'i,o;ure of
85)" m.c. and it is considered that the tr.'e figure is
markedly lower aue to exchange a"d dilution of thfl
isotopic composition of the infiltratL1€ 'I[aters as they
pass through the calcretes of the KaLvl:'.ri Beds.
~ped samples from two of the boreholes cave conJiderahly
older dates of around 20,000 years BP.
l'he ruai.Ll concern of the projec~ over this y~rt of t~le
- Z7 -
stratified. It has been suggested that it ~ay be a
worth',rhile exercise to date samples from different depths
in the boreholes. 'fhis would require some fOIm of pac'<er
pump tests.
8.5.3 (b) '£ritium Dating }'irst Strike Haters: Results from these
samples showed the need for using longer lived isotone3
14 such as C for these studies. ,HthougL sorc,e of the ~'.lI.
results showed counts of over <oero, the Llterpretative
reso;l.ution was sO poor as to make the results of uoubt-
ful v"lue.
8.5.5 (e) i'ritiwn J!rofiles of the Unsaturated ';0018: ywed or,
sharp iL1Cre8.S8 in the 11 concentrations :'0 ':.bove lOI.rU
in 1962/63, these were interpreted to sho\{ ",,"ism
infiltration (ie 1962/63 Or later) /lS !,;:,vin;7 re"ch8d
dejCths of 4 to 8 metres belc" grouna in ',11 ccess
the \:;~terta.blG is ;ilodern.tely shRllo\.; in t:lt: bot-:o!.: of
larce rossil vo.l:J.ey It Curre!lt1y the resu}.t.3 of J..;i:i:.; ')e.rt
of the i30tope ~~tudies n.re being i~tcrpretod in ~!~C
in the second opecial stUd.ios contract" (j,lhis ifLtc:r;Jr0t-
ation Kill be presented in the report lr,r;lC/o"
8.5./~ 't.S regardG to future isotope ntudies 9 the pro;j~ct taG'l fG(~l
tha.t the :'Iuclear l'h~rsiC8 Research Unit of the :)niverGity of
but the resu::.t.J are of ton of doul>tfl11 value ':iu(: tn ~;h8
groundwater ::;2ffi~)ling techniques usedo '.che onJ.s, ~,:':ere foro],
- 28-
will then make the isotope interpretations more meaningful.
90 PROJ-JJ01' TlWT&OlU1 ;1.HD E;D1PHENT
9.1 Transport
9.1.1 As of the end of July 1978, the !:'roject has the folloYling
vehicles:
Bedford J5 - 5 ton truck (BX 5025) was purc);esed in lJ0cen,ber
1976. It has covered 41,000 km and is :Ln good running order
despite a major accident in Narch 1978. It is used by the
GS1U assistant hydrogeologist, C. Uheney.
(Cost 1'8250.00)
lJedford J5 - 5 ton truck (EX 397C) has beeE )covicled by thc
Gi>. It is used by the GS1U assistant hydror:eologiClt
J .. Baron ..
Land Rover Stgtion "?Fons (EX 5185 and 5213) \",ere delivered
in bte ;';ay 1977. they have both covered 32,500 km and are
used by H. JOllCO and J". ~'arr. EX 5185 is fitted l",ith a
spli t char"ing facility and thi.s I\:lS caused :";ro blems d'lC to
faulty wiring being fitted at the factory.
(Cost 2 F.o.b. rlO,72U)
Land liover ranelliagons (Bj; 5241 and 5248) were delivered
in l"te June 1977. They have covered 34.00(; il.nd 28,0(;0 km
rec;pectively. BX 5241 is used by C. Cheney, :',;~ ,)248 by
J. Baron. VJost 2 ~'.o.b. 1'9,80U)
I'wo of the Land Rovers have suffered broken windsoreen
mountines.
~9/ .. .•.
- 29 -
9.1.2 With the existing operating conditions and field use, the 5
vehicles purchased by the project should provide dependabJe
transport for the next three years.
9.1.3 As part of the future project oro,'7,ramme, it is intended to
undertake pumping tests at certain sites in "",stern and
Central Botswa.'1a. The project will require an additionnl
Bedford J5 truck to carry the pumping equip~ent to the
sites. The burvey will not be able to provide this truck.
It is, therefore, proposed that the project shoulJ purchase it.
9.2 Call1ping Bguipment
9.2.1 Until the beginning of the drilling contracts, the assista.'1t
hydrogeolocists, C. Cheney and J. llnron had undertnken the
bulk of the <';SlO field work. Each has n larc:e caraVan and
basic camping equipment provided by the Survey 0 'l'he ,; roject
purchased extra items to enable them to est,~blish confortable
base camps from which they conducted the hydro('eolog'ical
reconnaissance work.
9.2.2 The commencement of the drilling, oorehole 10l',,,ing and pumping
test programmes, coupled with the appointment of !l. permanent
team leader, has meant that J. Farr has spent more time in tile
field during 1978. A caravan had to be temporarily hire from
SSL to accommodate him, tocether with, on occ",;ions, Dr. IC. Bath
on his special studies visit and various ;,urvey staff members
during their fieldwork for G310,
9.2.3 its field work has progressed in 1978, it has becone ohvious
- 30 -
that, to operate efficiently, the project requires two small,
easily to.u,ble caravans to accommodate the hyd!'o"eologist aIld
geophysicist undertaking the planned borehole logging and
testing programmes. It has been proposed. that the project
should buy these caravans as the Survey cannot provid.e them.
9.3 .t'umping 'rest )!;guipment
9.;';.1 ';'he project pumping test equipment consists of a trailer
mounted power "lant (4 cylinder .t'erkins diesel) fitted Hith a
clutch, 4 speed gearbox and V belt drive. 'l'his pL:nt drives
both the 2 ~·lono pumps a!1d the 5 ton capuci ty hy irQulic ",)'inch
used to install the pumps. 'fv/O Kent flow-meters, [.Old 5CU
Lletres of lay-flilt disoharge hose have also been purcha"ed.
9.).,2 'llhe ptlmps are a 100 mm. diameter J'ono '3l-flC0 ·::;1~ a I'-;.e ['11.1
9.).3
die.Llater Eono BH20UJ). '110 complete the unibJ thel~0 ,u~e l?(
(" , ~I 11he ca}:L·;.r;ity of the BHIOe ·';·U!::p with the 65 Ill::! risi"l:;
'7
[lain i:--; v.'lriable between 15 .. 5 m.J /hour u.t 1:3 rr,et!'es of
head to 23.4 m3/hour at 12C metrns of head. ',iith the
head dependine on the ,sr;eeJ of rottltiG,n of' the ~illl~)~
mD.in is varif:i.ule botlvee.!1 54.7 m3/hov.,:~ ",.;.. 1< ::letr,].'.5 of
head to 46.4 m3/hour .':it 150 metres of ~"'e,il de",uenc\ing on
- 31 -
the speed of rotation of the pump.
9.3.4 'rhe BUI00 };,-1Dl'P Was ordered when it became apparent that the
140 mm diameter BH200D ';QuId not go dOlm many of the 150 mm
diameter boreholes which the project had scheduled to test.
9.3.5 'rhe total cost of the above equipment is around ~13,30C but
this has been adjusted due to the project' s 1'1~_rral'ltee claim
(Section 5.2.14) to around Pll,500.
9.4 Borehole Logging Eauipment
9.4.1 The project h813 purchased the following borehole logging and,
sampling equipment.
Supplier: ':lindart ";ngineering Ltd., UK.
2 Logging reels complete "i th 300 metres of 6 core cc.ble
and connectors - (Cost ~2,280.00)
2 Depth samplers "'ith firing units - (Cost Pl050.00)
2 \iell head tripods - (Cost ~600.00)
2 Conductivity - te,operature probes (Cost ~75(;.()\Jj
::iullPlier: V" aleport j)evelopnents, m,.
1 Impeller flowmeter 70 mm in diameter
1 Inpe11cr flowmeter 127 mm in diameter (Cost ~90().(;0)
Supplier: Bryans Southern Instruments Ltd •• UK
2 Chart Recorders. !-loa.e1 2800 dual pen (Cost P~70U.OG)
:''upplier: Wayne Kerr Ltd., UK.
2 Conductivity - '£emperature Bridges (Cost 1'2250. GC)
32/ 0 •••
- 32 -
9.4.2 On "rrival, the Ilindart equipment proved to h"Ye been inadequately
packed and to have suffered damage during shipment: The
manufacturers were notified of these deficiencies. Subsequent
field use of this equipment has shown it to leave much to be
desired in terms of reliability and ruggedness especially mIen
considered with its purchase price. 'rhe loggin" cable reels
in particular have given considerable trouble. GSIO technical
note Ho. 2 "'rhe results of the GSlO logging programme in the
Kweneng Block" reports on the use of the eO,uipment in the
field and on the results obtained.
9.4.3 In addition to the above equipment, the project have an ,,1' -
Resistance probe, a multi point resistivity probe, a gamma
probe and a gamme module on loan from IGS, London.
9.414 All of the G310 fOnllation logzinz has been conducted by a
Survey counterpart (E. I,iilner) using the modEier! :!er:rh"rt
Owen Logger. 'rhe results have been very satisf'octo!"J, but
there is a need to up-grade the equipment by [.d'ling p mPirnetic
tape recorder and an induction probe with the3urLlcG nodule.
It is proposed that GSIO purchase the ",agnetic tupe recorder
from the 1970-79 equipment fund.'>.
9.5 Other Equipment
9.5.1 'Ehe project have purchased t)le folloi1ing IJajor iter; of
equipment :-
10 Hunro Type IH 95 HkII water level recorders cOrlplete
with covers, clocks, gears, tapes, floats,
counterweights, ch'lrts and spares: (Gost J:7869.CO)
nl .,/ // ....
- 33 -
2 Electronic Instruments Ltd. Conductivity Heters
(Cost .1:'410.00)
2 Base Barographs: (Cost P340.00)
1 Bell and Rowall iPressure transducer and
transmitter (Cost ~1500.00)
4 Racal TRA 1341 HF Radiotelephones: (Cost 1'10,(00)
3 Electronic Instruments Portable pH meters:
(Cost J:'757.00)
10. FINANCE
10.1 At the end of the iinallcia1 Year 1977/78, the a.ctua1
project expenditure Was ~312,974. At the end of July 1978 the
Qctua1 expenditure or committments were approxiJ:1ately ~450,00U.
'l'he original provision from the UK Capital .dd fund was
·£379,198 (k'678,766) at a notional exchange rate of £1.00 =
~1.79, In ilUCllst 1]77, the project estimatefJ for 1978/79 "ere
based on a total provision of k'740, 000 but V,8 tot"l "rovision
for the project; now given by the Hinistry of c'i.n:Jnce l8
):642,932,
10,2 In order to aSsess the time and oost "ffecti'Jeness of the
project up to the end of July 191'3, tables are given in
"ppendix 1 showing an approximate breakdo1ffi of the tir18 J)lcl
cost for eaoh of tbe study progrr-;l,mmes<, r~he 00StD t3i.V'3n [;.1'8
exclusive of overheads [;lld it is accepted ti:,:t th0~r !:ire o')en
to correction 0 '1:he basis of tn.E.~ c();"Jtings l~.)
',ppendix I.
34/ ... ~
- 34 -
10.3 Details of the proposed future project expenditure are
given in the 1978-80 project programme.
10.4 Prom th-e tables in Appendix I. the main stu"y
programmes up to the end of July 1978, have cost the projeot
K362,025 and the Botswana Government P85,4l2. The balance of
the project expenditure .pm ,975 ():'450,000 - 362,025) has been
spent on purchasing equipment; major items ):'32,900 (Seotion
9:4 and 9.5), pumping test equipment Kll,500; Preieht 1976/78
):'11,500;, vehicles );'20,000 (depreciation accounted for in
Appendix I); and minor items of drilling equipment (Soil Test
Rig), tools and other equipment, field expenses etc., K12,000.
11. REl'ORTING
Regarding the formal record of the GSlO Project work, it is
proving advt~ .. Y).tageous to prepare concise sUlllrw.rieo in the form
of GSlO Technical notes and GSlO Reoords, in addition to the
technical report series instigated in 1976. rhe Technical
Notes are essentially background notes to aid the planning of
field work and drilling programmes, or technical notes examining
the results obtained usinl\' various techniques or methods of
investigation. The (iS10 Record "aries are il record of the
various completed stages of the project wOl'k Le. a summary
of a drilling programme, or a completed groundwater inventoI"J
of a map sheet. It is hoped that the Technical Hote and
Record series will considerably assist with the final
reporting on the );'roject.
At the end of July 1978, the folIoving reports had cOr';jleted
or were being prepared.
35/ ... ~
- 35 -
QSlO REPORT SERI~
QSIO/l "Botswana: the role of hydrogeology in water resource
planning." S.S.D. Foster and J.L. Farr (October 1976).
QSIO/2 "Compilation of ground.water maps -- experience in the
use of data on the QS borehole archive." J .H. Whitelaw,
J'.L. Farr and I!.S.J). ~'oBter tSeptember 1977).
QSIO/4 !lA detailed evaluation of the pollution hazard to
village water-supply boreholes in l!:astern Botswana. "
W.J. Lewis, J.L. Farr and. S.S.D. Foster tJune 1978).
QSIO/5 '~An appraisal of the ground-water resources of the
Bcca :jeries in Gentral Kweneng in relation to Swaneng JJiamond
~!ine development." S.S.D, Foster and S.L. :'arr (in preparation).
LlSlO/6 "The likelihood of recent groundwater recharGe in
Central K"eneng. "So S. D. Foster tin preparation).
GSIO Technical Notes
No. 1 "A background to the (tSlO Serowe Block Jrilling l:'rogrs'llIlle" -
C.S. Cheney (in preparation).
No. 2 "The results of the (lSlO logging progr=e in the
Kweneng Block" - S.L. Farr.
No. j "A background to the QSlO Transvaal ,~quifers drilling
programme" - S.L. Farr and J.H. Baron (in preparation).
LlSlO RECORDS
No. 1 "A SUllullar:r of the SSL drilling programme in Kwenenl'
District" - J. Baron (Hay 1978).
36/ ....
- 36 -
No. 2 "A eroundwater inventory of the I.iSl0 Kweneng stud:.'
block." H.J. Jones Vla:\' 1978).
No. 3 "A groullciwater inventory of the I.iSl0 Serowe study
block." C.S. Cheney (in preparation).
No. 4 "A ;,\unmary of the SSL drilling programme in the Serowe
Block." C.S. Cheney (August 1978).
No. 5 "1.i310 l:'rojeot Review June 1977 - July 1973".
N.J. Jones (AUgust 1978).
ll.iS Reports: Special Studies Uontract.
Report No. 'IID/OS/77/23 "l.iroundwater recharge research in
Botsl1ana
(;310 project - Studies in Central Kweneng using cheroical
methods" - A.H. Bath (December 1977).
other reports on the gecphysical investigations in Kv1eneng
and Serowe are under preparation but h<lve not ."et been
allocated numbers.
30TH AUI.iUST, 1978 I>l, Jo JOi{ClS GS10 'r8rt,;.'>i L~iA.DBR
HJJ/SSH
IIPPEHDIX I
3'fUJJY PROGRIIJ,JMES - FIl'MCIAL 31JtlMARIES
TABLB 11 BASIC COSTS
'i'he following figures are provisional, partially inforned estimates
covering the staffing, transport and other specific costs exclusive
of overheads.
(i) citaff Costs
DAY RATE rula and 30urcc of :fundS
TYPE OFFICE FIELD GRADE OF CONTRACT
*om * PROJECT BG
0])1, PROJECT
(TCF) (TC,,')
Hydrogeologist TCO 55 - Housing 63 4 ,
GeophYSicist Seconded lGS 55 - Housing 55 -Assistant llydrogeologist TCO 45 - Ilousing 53 4 CS Chemi3t OSAS 20 - 40 20 -CS Electronics Engineer 03AS 20 - 40 20 -
JG
-4
-44 44
Technical Assistant T5 Local - - 9.50 - - 11.50
Driver Local - - 5.60 - -
Field Crew Local - - 3.40 - -..
ODH Salaries, OS.'\3 Allowances, ~'S,\, etc.
(ii) Chemical Analyses
(iii) fumping Test
(iv) Tronsport
Land Rovers
CS10 J5
GS J5
(v) Soil Test Rig
(vi) Reporting
~10.00 each, cost to BC
~50 • (.IQ per day, cost to .t'roject
.t'0.05 per km. cost to Project (Depreciation)
1'0.20 per km cost to BG (Running)
- 1'0.06 per km cost to ~ro.iect (JJepreciation)
1'0.30 per km cost to BC (Runninc)
- 1'0.36 per km cost to R:: (Jepreci,rtiQ" ~nd Running)
.t' 125.00 per d,,-v cos t to BG
1'75.00 per day <'55 to OY':, 1'20 to BG.
7.60
5.40
Al'l'ElTDrx I
'TABLB: 2 sm'TI'~hRY Ui ~Slu F:\ROO ;\.!"JTIli'ER ~V!J).lATIOH:·) Ii: Kfi&.-r~~r:}
Cost Pula
Programme Item CSIO end ilS Inpu t Ho. Days
011>1 Pro,i ect BC
Office Compilation of l~sistant Hydrogeologict 60 2700 - 570 borehole and geological data 1'echnical "ssistant
Field Verification of Assistant Hydrogeologist 62 3286 848 2660 borehole data Technical Assistant + 3 Field Crew
GS Geophysicist + Technical Field 80 4400 - 5592 Geophysical Surveys Assistant + 10 Field Crew Office 40 2200 - -Core Drilling Seismograph Services Ltd. 224 - 209,155 -
Supervision of Drilling Assistant Hrdrogeologist 151 3003 604 6478 Technical Assistant + 3 t'ield ere" ,
PumpingTes ts Hydrogeologist + 2 Technical 30 1890 1620 1611 I Assistants + 5 Field Crew
i
nydrogeologist + GS ! Borehole Logging 10 830 40 700 i
lHectronics iingineer + 4 field ;;rew i ~hemical analysis of GS ChemistrJ Section 30 Sronples - - 80L I ~"ater Samples ,
I
2 OSlO Land Rovers each 30,000 !on - 3000 12,vOO i Transport
9,000 ! 1 GS J5 Irruck 25,OVC km - ------ - -- I. " ______
~----- - - ---- -- - - - -- --- - -- - ~~---'
1'aule 2 cont/ ••.
-,-'able '- cO~1t/ .... Cl
- ------ --Cos t Pule.
1'rogrw.me It 81,1 ;";:.)lU :Jtct ;.j In:jiJ. t 1':0 • .i)!l.ys
CDi'" Project J5G - -'---' --
Freic:ht - 5()C -Core i'hysica1 1'roperties lliS Lond.on -lJetenni!12tions
IG:5 - 320L: --
Report (;310/2 35 1925 - 700
(;S10 Record No. 1 7 385 - 14-0
Reporting
GSIU Record r!o. 2 25 1375 - 500
Report G::i10/5 35 1925 - '700
.
SUB TOTALS 28919 218967 41451
TorrAL 289337
APP3:,DIX I
'l'ABLE 3 SUMM.:LRY 0)1 (;310 KARuv l·,tJI}l~R ~NALL:,:l.~L1IL!Ir3 I:: SBRO\;l!;
(;ost Pula .t'rogramme Item GS 10 .\:.; D \1;3 IH!-'lrr No. D",,(s
OD" Project BG ,
Office Compilation of bore- Assistant Hydrogeologist ,
75 3375 712 I
hole geological data rllechnical A3sistEnt -,
Field verification of ASsistant hydrogeologist borehole data technical Assis taut and 5 crel< 70 3710 zeD I 300)
GS Geophysicist and Technical ~'ield 65 3575 - 4803 ~ophysical Surveys Assistant and 10 cre,;
\lffice 15 825 - -Core Drilling Seismograph Services Ltd. 122 - 78250 -
~upervision of Drilling Assistant Hydrogeologist 60 3180 240 2574 Technical Assistant and 5 crew
Borehole Logging Hydrogeclogist and CS 12 996 48 840 ~lectronics b;ngineer and 4 crew
Chemical Analysis of \later GS Chemistry Section 80 samples - 800 SaIn?les -
I 2 G~ 10 Land Rovers Total 4l()00 km - 2050 8200
Transport 1 CS 10 J5 Truck 30000 km - 1800 9000
I Technical liote No. 1 7 385 - 140 ! Reporting -I CS 10 Record No. 3 7 385 , - 140
Sub J.'otals 16431 82668 30212
TOTAL 129311
,.?hl;JIX I
'2kBLE 4 SlJ;,Ji.,"i.RY Oi ::':3 lLl n.ECH!\;·{;.}:~ RE]£ArW:~ D; K";"i~:·:SHG
Programme Iteo
6quipping Mobile Laboratory
Aueering, air hammer and air core drilling
Supervisicn of Drilling
Analysis of Samples
Special Studies
Determination of sample hydraulic properties
Transport
Reporting
(;SlO and G3 Input
Hydrogeolozi3t, :]$ Che~list, Carpenters, etc.
Rodio SA Ltd.
Assistant Hyd,,-ogeologist Technical Assist;}nt .and 5 crew
GS Chemist, 2 Technical Assistants
]Jr. A. Bath IGS
Dr. B. Yerhargen Isotope Determinations
GS Chemist, Technical iiSsistant
2 GS 10 La."ldrover
.2 GS J5 Trucks
Re1lort GSlO/6 (Y~t to be completed)
* Half time and cost shared with Pollution Study Table 5
Noo DBY3
" 15
36
36
4,t
34
10
5 000 km
5 000 km
16
Sub 'l'otals
Gost !'ula
Ul£~ Project
1 125 6 000
20 90L>
1 908 144
880
8 500
10 000
200
250 .
300
880
4 993 49 794
TOTAL
'l'he total expenditure of the mobile laboratory h"s been depreciated over these two studies.
BG
800
1 544
2 948
555
1 000
3 300
320
10 467
65 154
-'P:eill;DIX I
TABLE 5 SU11l>iARY OF G;)10/«S12 "ORh O;i LOCHlJDI Tmlit)liII' l'OLLU'l'IOIl S'J'UDY
Cost fula l'ragramme Item G~ 10 and GS Input Ho. uays
O.lJi: Project BG
Hydroffeologist, !;.s GbeJ'tist, * O:quipping nobile 13.borator-,f GS Carpenters, etc. 15 1 125 6 000 e00
[Ulcer, air hnmmGr and air Rodio ;;:, Ltd. 17 - 8000 -core drilling
GS Chemist &~d Technical Field 25 500 - 1 3S7
Analysis of Samples Assistant Offic:? 8 160 - 392
Borehole logging Hydrogeo1ogist 1 63 4 - --Pumping Test Hydrogeologist 2 126 208 -,lurveying • Hydrogeologist 1 63 4 -Auger Drilling GS Soil Test Rig 5 - - 625 !
,
Physical l'roperties detprrninations on sanples
Technical Assistant 10 - - 95
GS 10 Landrover 800 kIn - 40 165 'transport
GS Truok 000 km - - 288
, Reporting Report (rS1O/4 14 770 - 280
:'u b 1'0 tals :5 477 14 256 3 282
TOrfAL 21 015
* Half time and cost shared with Recharge Study Table 4
A,PP,,;ilJlX 2
SUNJ.:;.lRY m' SEISfiIOGR..iPH s,:anc;;s LTD. DlULLTIiG lJ'J TH); GJll: K,ilill;lillfG BLOCK
Jiate No. ;,llifts Drilling Shifts (rock rolline. Hetera~e ;ietres Cored Joletres (';orin,f; .Jhifts coring and tripping) lioc\: ::tolled
.lUgust '77 10.50 5.25 126050 7';.00 51.50 I 1050
September '77 22 12.25 376.12 lSC .24 1950 00 I 6.50
October '77 22 12 436.40 1:56.75 299.65 4.50
November '77 23J- 14 :;iJ5.40 287.U5 18.35 10.50
December '77 Standby '.Hme ,
I January '78 25 10.25 317.30 274.30 43.00 6.00
February '78 24 I
70.10 4.00 8.25 303.48
I 233.38
harch 278 24 2.00 81.00 26.80 54<;>20 0 6 50
151 64 1946.20 I
1213.52 7"52.68 I :5 3. ')0 I -.-
Contract <,eriod 20th August. 1977 to 31st EaI'c!:>, 1978 - 224 days
Number of holes drilled - 22
Total Cost (Including standby time) P209.174 (including local invoices a'1d saterials, but excluding pump equipment)
Cost/metre
Cost/shift
m/drilling shift
Average drilling Contract overall
.n07.47
Pl 385.25
lincluding materials)
(including materials)
:;iJ.4lm/drilling shift
12. 89m/day
APP8llDIX 2
SUI'il'IflRY Ul<' SSL DRlLLItJG IN '£Hi:; liS10 SllROiii>: !ll()()h
Jiionth Total No. Productive Total Cored rietres Straight ])rilled Reamed Shifts Shifts Meterage
)ril 1978 S T A N D B Y T I H E
!Y
me
lly
)tals
-1978 24 14.75 372.60 285.30
1978 29 15.25 378.35 233.35
1978 19 9.75 252.05 204.05
72,. 39.75 1003.00 722.70
Contract Period I'Tay to July 1978
Number of holes drilled
TOTAL C031' (including April atandby time)
Cost/metre (including materials):
Cost/shift (inoluding 1'l:J.teris.1s + April standby time):
Average Drilli..'1g Progress/Producti.ve S11ift:
Average Drilling Progress/Day (\',1101e Contract):
Netres
._.
87.30
145.00
48.00
280.70
J1etres
82.00
305.50
48.00
435.50
72 Shifts
7
.P78,465.5
PI, 03<). 81.!
25. 23n/ sh ift
13, 93rl/lJay
Coring ;;11ifta
18
11.5
12
41.5
UNDERGROOND v1f;TSR R.SSOiJRCES EVM"UilTION PROJECT - GS 10
PROJECT PR00RAJiiIJE 197 8-80
1.1 This 1978/80 programme is based on the resul ts of discussions held within the Departm8nt and l.1inistry over the 1978/80 Project Proposals submi tted in f"arch 1978.
1,2 The proposed staffing of t he work programme is shown on table 1. Wi th three of' the ProjGct team ei ther on leave, or due to go on leave during 1978/80, alloN,snces have beGn made to cover these periods,
1.3 Outside the Survey's Hydrogeology Division, the main elements of Surve3' counterpart input will be on surface and borehole geophysics and hydrochemi stry.
2.1
2.2.1
2. 2. 2
2.2. 3
2.2.4
2. 2.5
KllROO M~.UIFER STUDIES
The investig2tions in the Sorowe Block were completed as far as possible ,"i thin the timing of the drilling contract in July 1978. It proved impossible to construct abstraction boreholes and hence purnptt3sting was not undertakeno
The Hork of extrapolation of the data obtained fo!' the Karoo from both the Kwe!leng and Sero,·,.) blocks will consist of a re-evaluation of the groundwa ter de ta eveil a ble in the Survey orchi ve and the logging and test pumping of existing boreholes.
It is envisaged, th"t 20 to 25 boreho1os ."ill be logged and tested during the first half of 19790 Of theso holes, 8 are located in the Kl1eneng stud;)' block "here aS10 have constructod observation holos close to exi sting production holeso The remainder will fall ",ithi,n the degree square map Sheets 2125, 2225, 2325, 21261 2226, and 2326.
In most rGSpeC~8 !}SlC is nOi'J NolI oquipIiGd to undertake this vJOrk wi thout outside help, Full det2ils of the equipment avd1able will be givGr, in the 19'76-78 OSlO pro~cct revie,., which has been prep3red for submission in lc,te ;,ugusto
Problems duo to the poor stst,) of repair of pumping plont, interruption of supply and subsec:uent breakdown are foreseen in using oxisting, equipp.Jd [md priv3tely oM1ed boreholo. Preference will thorofore, T/nll be i~ivon to using equipped or ul1equipped govornmen t owno d boreholes.
~'Jhile thore ap:pO.:1r to bo r:, few governm::n t oi'ffiGd boreholes for GSIO to test, thoy ,?re not l1ocG8s2rily in pr'j·;'::s of h;)rdrogeological intorest'ft ;, ddi tional drilli:lg will, thorefore, be required to (a) complC"k the Ccvc "o~dstonc invcstigations in the K1'Ieneng Blook and (b) to test those Ar838 whioh ;,rovG of in tGrest from the reeva 1 UP tion 1;rork of the 8ur-..re,r 2rchi ~"Oo
The borchole logging awl tcsting rrocrmnme will stort wi th the 8 boreholes in Kweneng (Jnd bn mov.:; to r·lokoba District where several
/2 ..•
- 2 -
of thG drou:;ht r'3licf boroclOles drillod in 1964-65 are reported as l.ll1equipPGd a'nel Dvri12Ji for testin.I;o Unfortu112toly these holes are no lcnger govarnm"nt b'D.·.d C'.fJ they were solt off to the public in 1968.
2.3 Experience hc.s ShOWl that opch major aspect of the \,ork outlined above Hill requi~c the i.'uli timo ;:::ttention of a hydrogeologist. It is therefore rroposod ',jpt the project IGador (MJJ) undortakes the re-ev21uation,f th" 'ccroo d~ta ,Commencing mid'"'Scptember +978 while the deputy proj ,c'; le cLr (JLF) will supervi[Je the logging and testing progr2!llmCGOmmon,clng January 1979.
3.
3.1
In the revised, 1978/79 estimatos, the necessary funds have been requested for oddi tional v.ohiclos 2nd Caravans required to su.pport at least one of these h~'drogGolob>ists in thc field.
GllBORO}1E - LO?llTSE !)ROUND",.·,'I'ER INVESTIGilTIOllS )
The primary objocti'TG of these invGstigottons is to evaluate the possi bUi ty of using Rddi tion91 grou.ndW? ter from the Transvaal and possibly HaterbE.rg System .~quifers to augment the Gaborone - Lobatse water suppl;y. "ihilr it is not )·et possible to define the programme in detail, tho mcjor gro1U1dc;2tor :orospects are considered to be the main outcrop~ of the kerstic ~rcnsva21 Dolomi tos around Ram~tswa (about 12 km ), BathoGn (8 km ) and northern Lobetse (16 km ) .•
EvidencG from tile Gouti18rn Lobatso outcrop area (about 5 km 2) and abstr8otion rocords shov! t:.))~·t tho E1yuifGrs have a fair storage capaoity and thot tho)· roceive. certain 3mount~ )f annual recharge. It is ther3fore rooed blc tha t ,yound>lotor supplies of betweon 2000 and 4000 m /doy may be locnt"d Hithin Clach area.
3.2 Prelimin8ry ",ork on coL C"inf; and. compiling the data for this study started in Lpril 1978 DId curruntly work is progressing on the preporotion of ".ho borcholo inventor::'~- fol' r"ur 1: 50 000 map sheets (2425D3, 2425~4, 2,',25Ill cnd 2525B2) covering the Transvaal System between Gs borone and Lo be :S8.
In 8ddition, a boreholc inJontory has be on oompiled for the \'Jaterberg out-orops of the Th.::mcg2 end Ootse areas.
3.3 In the revised 1978/79 estimatos, funds w"re requested to be .brought forwarl from 1979/80 to finance 11;1',0 drilling required for this study; Ilf vieN of thiS, it is propose"- that the current SSL oontr"ot be extendol to cover this ld,ditionel work (drilling taking plece from Sept"mber to Yovombor 1978). Investigations will begin on the northorn Lobe'cse oU'~crop and v!ill include both abstraction and obsGrv.-:> tioD boreho18s.
In an 2rSe of priv8tE- fr:rms,' Ol.<mors permission will be necessary prior to oomr1encemon" of the Hork unloss the work is to be conducted l.U1der the terms of t.~le I,,'lin:-Js and l\'iinerals :;cto
3;4 In "ddition to th· s';udy 0: the ';'ransvaal dolomites, attention will be given to the grou:,dTNEl~,~Gr potential of thG l:Jaterberg System formaHails around Thi;m,Gf''! ",nil 06t"'3' Tt is ll0'pe'd thd an additional
4.1
4.1.2
4.1.3
- 3-
programme of moni toring sprinG flows in thesG are88 will also give useful inforrr.ction on groU1:dl~l."ter rGch,~rge and storage within the Waterberg System.
EVALU!,TIor OF R:J:GILllGE
Botswana's clim:~te is charDcte:rised by '3 scasoDf'll ond highly varinble ::.'8inf.?11 rCi:::ime 1'-ihich Cc:Jll be ex:)coted to give risG to equally vari2ble >:70u..YJ.di"nt,::or r,3cherge potonti:sl.
In the Kt>1~h2ri, Und'3T the :;rJsont clim-::tic condi tions, if recharge is takin,.s plec,:, througl"l tho Kalah::ri Beds it is almost cert2inly the result of doep diffusa infiltr2tion of rDi~f.ll. The basis of the 1977 GSIO rech,'rgo st',;dies in KHeneng ",erc att,ompts to identify by a chemic21 and isotopic examination of water in the unsaturated zone whether such deop, diffuse infil tration has taken pIece in the recent p<:!st o \.rhilo thJ rosults of these rech;;rge studies have yet to be reported on in full ,}SlO/6 it appears th2t rocent deep, diffuse infiltration, if it haG taken rlcco, is Bxtromely limited and that much work Hill still '00 r00uired. to attomrt to quantify the results.
In eastBrn BotOltlCna, rech:-:>:rgo 'o~/ concentrcted infil~tr2tion from run off it likely to occur Hhorevor sur::::::,co run-off occurs. Attempts have been m~ do to quantify Guel: TGchergo b~r moasuring gulley flows discharging on to the dolomi tes 2round Lobotse (C. M. "I. Jennings, 1974 PhD Thesis pp. 226).
vThere springs occur ir: Eai~'~crn .3otc:';?n.3.~ it is l~sdrogGologically valid to indirectl c' evdu:,tc r3chprgc by monitoring the spring dischnrgcs 2.nd 2ny 2hstr2ction th<'t is t2kin,;; pIDGE:- ~.1ithin the spring ca tchmen t.
Long term groLL'1clv·,13t.:.:r rirogrr!};ho DEy shcvf 1~hothcr rocharge is taking place or not; 91 though ;;i thout 3 de tailed hc'irogeological knowledge of the aquifer, it is difficult to interpret the groundwater fluctuations in terms of :r.-ochi1rgo £'inOlll1ts.
For the 1978/80 I'rOfp:'::mmc it is proposed to repeat a similar study to that executed in ]("Jonanc but 3ttomrting to tske the invGstigations down through the soil ;>rofi10 to the He.tor kblo. The full details of the programme cnn onl~l be 8st2blisDGd \1:!-:eD t~c resul ts of the report GSIO/6 h2VO been S8cn c-Jnd cliscussode> 'rho follo'l'!ing is an outline of the consider"::tiol1s to bo t3kon into eccount in planning the 1978-80 ;>rogramme.
(i) R2infe.ll - t'10 8 i t83 "'lO"'.l Cc be in an aroa ;,i th 8 mean annual rninfall of over 500 mm - long term dilil}' 2n1 if paBsi bIe, intensi ty raini'::11 r,Jcords should be evail,:~blG from a nearby moterorolcgic[',l st2tionc
the chomio81 composition of st l08st one season's rainfall shoul d be moni tore d,
/4 ••••
- 4 -
(ii) GrOUniH~~E. OCC.:3,rreHCe - it ,,,,rill b(~ ossential that true water tablo conditions occur at the ci tos solected. In these cases ground\"Btcr fluctU2.tio.~lS Dnd isotopic com}!osi tion 1.nIl have me8ningful int3rprotations.
if l:ossible the depths to the VJft3r tr'ble belo\1 ground at the citae sl'.c'-.:ld. r2rJ. ... :e bGt~.<](~on 8. fOlrJ ml)tr·'Js ,)nd 40 to 50 metroE~. Thio 'will C-GtL:blish l,·;hether 0.ooper infil tr2tion d.DGS teko p12ce. TLc SlE'llo"t'Tcr \r,lork 'Alil1 also help raduoe drilling costf.1o
follovling the c0mplction of th(:: Q.:1emioel and isotopic examination of the unsaturated cnd s!!turated profile, the water table; fluctu3tions vJill require monitoring over several seasons so thet groundv,yator hydro graphs can be constructeclo Should these produco worthwhile rosults, a future aquifer eve.luation ~")rogr8mme would engble the e.quifer storege properties to bo used to interpret the fluotuations in terms of rcche.rge ~l1d di ~~cl12rge val umes.
(ili) Loce.tion - On t~c "besifJ of the: distribution of the Kalahari Bods anc, reinfoll, threo 10c81i ties mao' be sui table for the rech:-·rge 'l:'ork;-
(i) the Phitshanc/Molopo ;,re'3 (100 km from Lobatse)
(ii) an aroa WGst of SJro~~ (420 km from Lobatse)
(iii) the ?'at& - 'lUkF3 ,.roe: (7D(, Lm from Lobtso)
It is hoped th3t c bri,f e:~min2tion of tha survey borehole 2rchive 1ttill id.n~1·~ii';y 8uit',blo sites e.t onc or several of thGse er '::;(~;3e
(iv) lJ1imin;?, - it is ho;.>::.:l th:;,t TtJoX'lc on suit8blo sites vJith shallow water 'GBblef: Can 8t(~:::'t in November - December 1978 using oi ther the Survey Soil Test rig or hand augers.
(v) Tracer Zxpcriem,::D ts: CO~1si 10r2 tion vlill be gi van to the use of chemical tracers to monitor the movement of the infiltration front at the tost sitas.
4.3 REeK,RGE IF .s;;sn:cm! BOTS'jUT:. 1978-80 PEOGRj,llME
4.3 Lddition81 rochergc ,.,ork will ooncontrete on the spring oatchments that iJ,]d the L::~rg81y })oI'onniol Kolobcng and MctsemaBh'l'Jane Rivers. This vJork should produoe fairly rBI-'i'~l resul ts with a good degree of accur,ocy. Initially this '"ork ~lill bo cttachcd to the Gaborono 10 ba tSG grOl,L'I1dw8: t'Jr invo 8 ti 'se -'Gi 0118 0
Sometime in lete 1979 or o3rly 1980 it is hored to oomplete a full spring invGr.~or;~{ for J:astGrn Bots 1:18nn.
5.1 Grou..."'1d"Ja-~or Quality: '~'he deterioration of groundw3tor quality in
/5 •••
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the abSGnC0 of current r'3ch?r~;8 an(~ w.h<3re the ! fresher'1 groundwater body is very thin is 3 r:otontial throat in aroas of established ranching. If sui table sCCellS to " sufficis<1t number of boreholes prov.:s l'ossi D10 GSIO rrOpOG08 to undcrtske a pilot investigation into tho vcriation of ")ctcr qu.alit;v ' .• ,ith dc;:;th in an area of low rainfall (Molopo or 'JhLm3i Farms) .'1nel in an area of higher rainfall and knOI'ffi \..rator qUDlity ·::··roblems (NDta)~ It is also rroposed to initiete some form of c;ualitJ·· monitoring network in potential problem areas in cooperation l,.ri tll t ho Survoy (Section 6) 0
5.2 Potential Karoo 32sBl t iJqui fors
SincG the Stormborg Basal t OCCU:)i0S a very Gxtonsi VG are of central Botswana and u:oderli3s areas of great ranching interest GS10 has proposed (GS10/l Section 3.4.2) to invostigate tha possi bili ties of minor equifors in the weathered. zones of the Basal t and theirpotential as ranching \'.~,,;;tGr sUl'plics. rooh 2 study would involve the re-8v,sluc:-:tion of 2~::::rci'ri2te ourrant information (with no new drillin.;; proposed) "ncl would probably take the form of a statistical/ economic 3nalysis of th3 bont methods to undertake groundwater schemes in such 9reas.
6.1 From the ;orcgT.emne outlil1oG. in Sections 2, 3, 4 and 5, it can be seen t'l')t the ;'roject t33CC '.;ill be heavily engogcd on the original proposals prcsonted in GSIO/l until et least the third querter of 1919.
6.2 s:'hore [:rc nOTr10vcr saversl :U'y~S of z:ctivit;y in irJhich GSIO and the Departm-3nt's efforts shot:,.lr;' "!)8 integrated:-
( li)
( .. , \ 111)
The do:,;.r'cc to 'which fuG re-ovelu2tion of the Surv~y data by GSIO s.:18uld involvo rert of t~18 re-orgonizJtion of the archive remains to be d.iscussod. It is :-::n 8rC2 where the Froject needs to v,Jork closoly 1t-d th the Dopartmont"
In vie"'! of the f'?'.ct t[:":~t thG GSIO rooh~.l'ge evaluation progrrmm8 ~r.Jill 2:' ~)C:::t.:ir0 lonG term moni taring of groundwater' levols J.E(/cr ~~Tclrocher::i;.·]t:;'''~T it is highly desirable that there :3tculc:. be close li~.1ison \"rith the Department OVGr the est?bli:::.dlrl0nt of this TIJorkCl Simi13rly there is a neen for the D8~)2rtmont to re-'·3ctiv2to ~.nd 81..'"P,')nd its long term monitoring of groundliJ2tGr lovels throughout Botsv·"rana. The logisticE? cs~',ociall;Y1 11)3d to bo :pla.nned so :::>8 :1.ot to GDonmh::,y 'shJ DO"i::-;:n:'tDcnt in the futuro e
S,i:"1c::; c.::::::,~:.'i~"'.. :.:'8 2::'~O ~.' vi 3i 'c. 1 08 .gI'0Und1,rJat.",r ::1i sch::-:rge 2 nd hence ::. f.<'\cit of -Gb·::;; ,.;;:.nour.:>J[:t::r r·:,;s'::/Urc(;s of the countr;y, it would be "rJ.V.3!l"t::;gOQnB if E.; joir:.t :}SlO .'~nd Dopertment.;o,l s~Jring
surv8~l o01:~1 ~ Lo Gst3')lis.~.1c:)"CI This lvork ",,\lould be ;:.artioularly suit'~'b10 fer the initial iYl-'~rodJ.ction to hydrogGology of a Locnl bcoloGist~
(iv) 11hrough t.ll:.} S~' ,,")cinl Stu:'ias oontrect Hork, c~~1phasis .,vill be pl£.c:?-::~ on vi3i ts b~7 s~!8ciDlists v,rho "(dill demonstr8te snd
/6 •••
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Bdvisc; the Frojoct ;3nd Department on various' teohniques used in zroundwr:toY' resources ovaluctioDo
Cv) ',·'ith the continued interest in gTOUnchlatar pollution, GS10 "ill be 2vail"blo to coll"borco.te with any further works which m?y be recommended i;~ Report GS10/4.
7. COUNT:8RP ... HT rrR ':IFING
7.1 iis tho Do')prtme!1"S 1128 provi::;io~.:.~lly s81ectod a g:;ologist to be attech-:;c: tc the prcjGct, tiL. following training time-table is proposed.,
7.2 On joining the project to"m, the g'lologist \·,ould prepare" spring inventory for E-'?stern :Sotsir.J[~na unclor tha supervision of the GSIO project leader. Thiro will ;lrovide an introduction to the hydrological o;yclo 9.na. to the hyc..rochcmic?l relntionships between groundwa ters and aqui fCr8<l
7.3 Following the com:,l:;tion of this work (until derarting for an MSc, courso in Hydro,;coloC:' In ,~G;:t8mbor/Octobsr 1979) the geologist will Clork alon ;8i:".0 the 0310 hy;lroG8010gints on the logging and testing of borGhole8.. ':'2his ,.,:111 l;rovid.o E' considerable b2ckground to the ~h~;·sice.l 8:1d. 8n~EineQriEb' si:~·:)s of e;round.l'iater invGstigations and o. . .Jvolo:.;mc:nt, Hncl 2 knoYilcdgc of the K&roo aquifers,
7.4 On return from thG !<J[)c, CCUrUG in 12 to 1980, the counterp2rt hydrogoologist ",ill thon teko up 9 -;ocition within tho GS10 team running in·lo~""\ond.0nt inv3>3tigations"
7~5 Should no geo10ci1.st 08 2V2iL::ble to join tha team during 1978/79, it is suggGsted. that [: form fiv~ studont should be selected for a Bri tish Council scholr:rship to 3tu~ Environmental Soiences.. On gr~du2tionf t~10 Etudent ·,·!oul(~ join the Survey Hydrogeology Division for on-tho-job trcining.
7.6 It is folt that the required British Council Soholerships could recei ve the support of om:.
8. FUTURE GSIO DRILLING RE(UI;n;MENTS
8.1 Without oddi ti·_'"31 fun ·'s boinG made 2vai18b10, the and of the contract drilling in Ncvemb"r 1978 \'lill SOG the bulk of the project's funds for drilling oxhausteds
8.2 As ind.icated in Scetic:'1 2. 2i> 4 of t~""lic l)rogl'E'mme, it VJill almost certainly be ncccs3nry to construct abstrrction boreholos in those areas of h3Tc.rog801Ggio~-1 inter~st. \rJh0re ne sui table existing holes Can be u80f or loc~tcdu
8.3 ':,coor tin,; thC'"G no Survey ~~rillir.:.g cr:paci t;y ~'Jill be available to the projoct, it is thG~cfo~e considarod necessary to request F200 ooe to P225 000 for ccntr2ct:lrilling foI' the period 1979-81. (a morc G':~ccific requGot for t~"!..esc funds \\;il1 be made once this 1978-80 ll:;'ogr,mme he" beon confirm"",). Should further drilling
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funcls bo m8clc aveilc~blG, it is OnViSD{;od that the ,drilling oontract should start in ;'pril - j,1GY 1979 'A'i th the tendering process being carried out in JanuAry - March 1979,
8.4 The emphasis of the futuro contract ccrilling «ill be f or the constTuction of abstraction and obS0rvation holes using the most economic?l methods possi bl,)? l'epi (1 air hammer c:rilling fOT example. It is folt that the "8,-,, core clrilling has probably produced sufficiont sr:mI',lcs to 1>3rform 2dquate physical pl-"operty d.eterminations for the Ecca, ancl Cav() Sands tone.
8.5 The qUGS-ulOYl of owncr8hil' E!l1"l dispo8,'}1 of the abstrnction boreholes construoted by tho FrojGct hOG boeD looked into and would appear that to minimise such :-roblems the Project should try and select sites in unellocc'tod aroas of I'ribal Land or in the State Lands. This, hO\,.J0v·3r? tn2;y :not bo h;ydrogeologically desirable ..
8.6 j,t all sites the Prcj0ct ,;ill hccvc to'"ork closely "ith the Looal Land n0,c:ri[~ cs ultim2tals tho;y, e.nc~ the hrat,~r ~JPportionment Board control the ri.,:;hts Over tn,:; use of ,3bstr3ction holes. However unior tho ,'Tovisions of the Boreholos j,ct, the Department retains tho rigb.t to m'eko tests on the abstraction halos for 12 months follOl,-:ring their comrleticDo
8.7 U!lller current legislation, hO·.'Jov,"i', it is very unlikely that the Project ;;ill bo , blo to recover' ny of the production hole drilling costs 311d t':'1o:J c2sis for Bn;y rscu~'o:ration of financo would have to be in the farm ef comr-Gns:.::~tion for improvoments tc' the land.
8.8 ~"':ithout a~Llition81 Projeot (~rilling funds, tho lira-vision of P40 000 in the 1979/80 Qstir:12tos L 0. the current b32.anCG of the funds are only sufficio:nt to cover ~he drilling required for the recharge inv8stige.tiorlEl 1--'.111 :~o88iblo l,ollution studios.
9.1 j,t thc un'l of the }'incncial Y2'.r 1977/(8, the actuel Project 8 X:) en::'i tures l,r8S F 312 97 i.:. out of tho tote] ]rovlsion of P740 000. rho 1976/77cncl 1977/7S n:c-ondi tur0S us 8umm3rised in the attached table tCGoth"" "i-Ul the roviso::, 1978/80-,stimetes_,
9,.2 In the 1978/79 8sti;::CtOLt the funds rG(~uastGd for equipment and vcbiclo3 ~rG ~ccoss2ry tc GOVor the nCG~S cf suppcrtinz at least cnG? 211(1 mc.3rbc t::,!o oxtr.?\ hyc1rogsoJ.ogistsin the fiiildc. Quotations Tcoeivci for th.e OP~8Venf) I'O':;:UiY'0::':" h;y GS:LO 8ho' ... them to cost around F3 SOC c:'O;ch" ~', ;?'<:l~ford 2"5 costs 08t1.;JOO:'J F8 coo to P9 000.
9.3 In the 1973/79 ·JDtim~'lt3E!. fU:'l(,~2 22'" ."108 b:rought fOI'h)3rd to cover the co!],tr"ct (rillinG' :Cor the GeDar-oDe - Lobats2 GroUnd1fl2tcr InVest1b'2tic'Yls" ';n ac:.c~it::.i.~nal P'!'2 .. 000 has beon vJarr3ntcd for 1978/79.
9.4 rhough tho requ:'c:t fer t;,o acldii;i.on:cl F2CO 000 to P225 000, to covor furth8r contr8ct (:rillinZ, ,.'.till rcquirG e Froject I.:;,:ldendum, it is, proioso:~ thn~ ~hese funds "rill DG used (:.urir~g the '1979/80 and 1980/81 fllOenclal year,~.
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9.5 Finally, no provision N8S m2c!.8 in the original OSlO Project Memorandum to oovor tho running cost of tho Projoot vohicles and plant. It presJnt, the Dopnrtmont is me>3ting these costs from it·s recurrent vote. It may bG r:::.visG~lG to r0vich1 this situatioll o
GEOLOGICj\1L SURVEY 30th ;;ugust, 1978
1>1, J ,. JONES GS10 TEJflM LEf,DER
1978 1979 1980 MAIN PROGRAMME ACTIVITY
~~.L~~~.L2......!!' . .JlL~J.!:'1.J..~t::!.L:I.-L.L...~--l-.~'-r-:....Q.. :!.~!:~ PE RSONNEL -- ._. _ .............. --
KAROO AQUIFER Dri tl i n 9 Serowe ___ _ OJher ares jf Q9reed CSC IMJJ !
STUDIES Pumping TQsts Kweneng Mokoba Serowe .,Qthe,L S!rLa~ __ JLFI MJJ
Surface Geophysics Serowe RJP
Borehole Logging Serowe Kweneng Mokoba Others RJPI EM ----------RGPorting - - -- Interim Main MJJ iJLFIJHB icsd ------ -Re-eval uat ion of Survey ArchiySls - . -- ------_ . __ M JJ lesc
GABORONEI Data Coll .. ction JHB
LOBATSE STUDY RQ-evaluat ion MJJ I JLF
Contract Drill in9 _ SS l P,85000 JHBIJLF
Pumping Tests J L F
Logging RJPIEM
R"port ing -- JLF IJHB - . ----- -- -_._------ -- . .. ---,-~--- --..... ----RECHARGE Ar"a I nves tigations - - - -- WJU JLFI JHB
STUDIES Spring Inventory 1.. ___________ GS Counterpart? Catch ment Studies -
MINOR STUDIES Groundwater Qual ity WjL/MJJlJLF
RELATED TO THE Monitoring
I Karoo Basal t - - - - I JHBIJLF LlVESTOCK INDUSTRY
Aquif,n Study L..
FIGURE 1: GS10, 1978.80 PROGRAMME
UNDERGROUND \,LTER RESOURCES EVf,LU1;TION PROJECT GSlO FINLNCILL REVIE,,/ - Jlll'lE 197 8
Head/Su. Head/Item 1976/77 1977 /7 G 197 8/79 Lctual ::ctu21 h8 ti ma te s
-- .. -.-~-~.
73-18--1 Scientific Equipment - 33,919 20,000
73-18-2 S:peciel Studies Contracts ~ 15,921 161 500
73--18- 3 Frei gh t - 5,466 4,000
73--18-4 Contrect Drilling - 192,158 212,000
73--18--6 Vehicle Purchase - 27,150 18,000
73-18-7 Loc21 Travelling _,llo\·)ence - ,1.87 500
73--18-8 Field Subsistenc() - 2,068 4,500
I irOS~\·.L 35,800 277,174 275,5C{) i
Balance cerried over to 19110/81 - P74,526
1979/80 Estimates
10,COO
16,500
4,000
40,000
--
500
6,000 ...
77,000