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.

3/ ....

June-July 1977

21 August 1977

September-October 1977

7 October 1977

October-Nov8nber 1977

October 1977

December 1977

- 3 -

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.

4/ ....

January 1978

Harch 1978

April 1978

l·fay 1978

June 1972

July 1978

- 4 -

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.

5/ •.••

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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;'

(j / ....

- 6 -

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

7/ .....

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~~

- 7 -

(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.

8/ ....

- D -

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

9/ ....

- 9 -

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.',' ••••

- 10 -

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.

1.; I •• ~ •

- 11 -

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

• i

- 12 -

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.

13/. "" .

- 13 -

~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.

- 14 -

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

15/ ....

- 15 -

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.

16/ ••••

- 16 -

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)

- 17 -

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,~.

. /8 •• _.

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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