UNIVERSITY OF THE WrTWATERSRAND, JOHAN~SaURG

NUCLEAR PHYSICS RESEARCH UNIT

GROUND WATERS AT ORAPA, BOTSWANA ~

ISOTOPIC, CHEMICAL AND HYDROLOGICAL STUDIES

~upmitted to de aeers Industrial Diamond Division

(Diamond Researoh Laboratory)

Chief Investillators

J.P.F.Sel1schop, B.Th.Verha~en and E,Mazor t

,Investili.ators

M,T.Jpnes, N.Robina, C.M.H.Jennings~ and L.Hutton

pf the aotswana Geological Survey and

Minas Department (Director; Dr.J.Hepwprth)

, .

t Professor of Jsotope Hydrology, univeraity of the Witwaters­rand, on sabbatical leave from the Israel Atomic Ener~y Commission. and the Wei~mann Institute of Science, Rehovoth.

rsrae1

~ Now with Messrs. Falconbridge Explorations, Limited.

f '.'

Acknowledgements

We acknowledge with much appreciation the support, helpful advice

and provision of samples and other materials from members of stsJf

of the

de Beers Diamond Re~earch Laboratory,

Anglo American Corporlltion of South Africa Ltd.,

de Beers Botswana Mining Company Pty. Ltd., Orapa, and of

Professor D.Midgley and his staff of the Hydrological Research

Unit, UnivelCsity of the Witwateurand, Johannesburg.

This investigation was made possible through the financial support

of the

University of the Witl~atel:sl:and, Johannesburg,

de Beers Industrisl Diamond Division, snd the

Botswana Geological Survey.

A BST RAC T ,

Th~ report deals with groundwater studies conducted at Orapa and

surrounding areas from 1968 to 1972. This includes observations during the

time in which the Orapa wells were in operation as well as studies on the

recovery after cessation of pumping as a result of the commissioning of

Mopipi Dam.

The observations may be ~ummed up as follows;

1) Contrary to Ilarlier theories, rain l'ater is acti.vely recharged into

the Kalahari bed~, forming shallow groundwater bodies. This is

manifested by the elevated tritium and carbon-14 values observeq

and by the seasonal variations in the tritium and Balt contents in

wells penetr .. ting no further than the Kalahari beds. This recharge

must be local, by rain infiltration through the Band cover and is

most probably being intensified by animal hole burrowing.

2) The basalt and Cave sandstone aquifers are interconnected with the

shallow, phreatic aquifers. most probably by joints and dissolution

channels. This is demonstrated by

(a) the chemical composition, which reveals a gradual

development from the Kalahari beds via the basalt

into the Cave sandstone.

(b) the coincidence of the Cave sandstone semi-artesian water

level with that of the Kalahari beds water and

(c) by the regional rise in the Cave sandstone water level,

most probably as a result of the exceptional 1967 rainy

period.

')

3) The interpretation of the tritium and carbon-14 results indicates that

(a) the Cave sandstone water is low in carbon-14 and therefore

old and of nearly static nature; and

(b) that the wells pumped Cave sandstone water with additions of

up to 15% from the shallm., Kalahari bl'ds or basalt aquifers,

4) The draw-down due to pumping was small and the rest level recovery

times were comparatively short. Hence the Cave sandstone aquifer

seems to be a steady and substantial source of ground water.

5) Borehole yields tend to be bigher the thinner the basalt section is

at the well site and the deeper the well penetrates into the Cave

sandstone.

6) It appears that existing wells can be better developed and that new

well sites may be located by a number of geological and structural

criteria.

discussed.

Recommendations on well siting and development are

7) The nature of ore treatment at Orapa mine is such that a large

proportion of the water used might be reclaimed, thereby significantly

lowering the mine's water requirements.

The conclusion to which these researches have lead may be summed up

as follows:

The evidence of rain recharge to the superficial aquifers; the

evidence of the interconnection between these aquifers and the Cave

sandstone; the hydrological behaviour of the sandstone aquifer,

its chemistry and its substantial water resources; the possibilities

of improved ground water exploitation and plant water reclamation:

all point towards the feasibility of resurrecting and developing the

ground water supply to Orapa mine, either as a standby or on a

long-term supply basis.

Introduction

Previous Work

CONTIlNTS

Geol08Y of the orftpa Afa~ The Genaral Sec~ion The C~ve sandstone The Cave sandstone-ba~.Il1t contact The basalt The Kalahllri Beds

Crete (ca1crete and .ilerate) The Kabhari Sand

Fossil Drainage Patterns Joints in the basalt Doleritic Dykes

Hydrology

Location of wells and bo~eholes Tested yields and abstraction figures Rest Level Observations Regional rise in the Cave Sandstone rest level Relative rest level draw-down during pumping Absolute rest level draw-down during pumping Time of rest level recovery after termination

of pumping Number of water ho.iaon. in the Cave sandston~ The semi-artesian character of the Cave

sandstone aquifer

Geochemical Comppsition pf the G~pund Water

Nature of the available data Major water types at Orapa CompositLon relationships between the I<alahlld

beds, basalt and Cave sandstone waters Degree of compositional uniformity of the water

in the Cave sandstone aquifer

Isotopic Studies

Nature of tritium and carbon-l4 as hydrological parameters

Tritium and carbon-14 results at Drapa Stable hydrogen and oxygen isotopes

Rain Recharge at Orapa

Possible Water Reclamation at the Plant

Recommendations

Well siting recommendations Well development recommendations Further research recommendations

References

Figures

Appendix: Indhddu;;\1 I'en data sheets

1

3

5

5 6 6 7 8 11 9

10 11 11

13

13 13 15 16 16 17

17 18

19

21

21 21

22

24

26

26 27 32

34

37

39

39 41 41

42

Table 1:

Tabl!! 2:

Table 3:

Table 4;

Table 5:

Table 6:

Table 7:

List of Tables

Bovehole profiles and tested yields

Tested ~ie1rls of Oraps well fields

Abatractioll percejltages from the com~ bined Orapa well fields

Cave sandstone rest level data

Average rest level data (based on Table 1)

Tritium concentrations in T.V, at different sampling dates

Carbon~14 and tritium data from combined sampling

Between pages 12 and 13

Page 13

Page 14

Between pages 14 and 15

Page 16

Between pages 26 anq 27

Page 29

INTRODUCTION

The Orapa diamond field is situated in the northern part pf the

Kalahari thirst1and. Until a few years ago no water sources had

been known in the area, except for a few shallow tribal wells of

limited yields.

In 1968 systematic deep drilling operations (100-325 m) were

begun by the Botswana Geological Survey, on behalf pf de Beers

Prospecting Botswana (Pty.) Ltd. and the Anglo American Corporation

of South Africa Ltd. In a time span of two years thi!:ty-two wells

and observation boreholes were completed. Twenty-seven of these

yielded water, between 5.4 to 27.2 m3/h with a total tested yield

of 2100 m3 per day. This record of success is of the utmost

importance not only for the Orapa diamond mine and plant, but in a

broader sense, for the water development of the whole Kalahari.

In 1971 the Mopipi scheme, by which surface water from the Okavango

is fed to Orapa, was put into operation and the immediate demands on

the local ground water dropped drastically. This permitted the ob­

servation of rest level recoveries, which has led to promising con­

clusions regarding ground water supplies, which will be discussed

below. For the time being the ground water is regarded as a stand-by

source in case of any future difficulties with the Mopipi installation.

Such difficulties may be envisaged, for example, if a succession of dry

years in Angola should reduce the water level in the Okavango to a

degree that will dry up the Boteti River; if seismic activity at the

south-eastern barrier of the Okavango delta should have an adverse

effect on the water flow regime; or deteriorating water chemistry.

The objective of the present research group was to study the ground

\,ater regime at Orapa, to assess the abstractable quantities of .'ater,

and to provide recommendations on the optimum ways of further develop-

ment of the ground water sources, in case of future demands. Much use

was made of data in the Botswana Geological Survey archives, but a great

deal of new data was also collected within the framework of the present

project. The tritium and carbon-14 low-level counting laboratories of

~ 2 -

the Nuclear Physics Research Unit were engaged in eKtensive measurements

of the Orapa samples. The large body of data collected was compiled

at the Nuclear Physics Research Unit. EKamples of such intensive

co-ordination of different types of hydrological data, such as drilling

results, geological units encountered, depths (and samples) of waters

struck, original rest levels and repeated rest level measurements, with

the detailed chemical composition of the water, the tritium contents,

carbon-14 concentration and the stable isotope composition of oxygen,

hydrogen and carbon, are rare indeed. This mode of attack as directed

to the ground water problem at Orapa is, perhaps, the most efficient one

in hydrology in general, but in remote developing countries in particular.

The main principle 1's that the maximum available information has to be

extracted from every water source available, and furthermore, that the

data have to be processed in the roost intensive way, using the most

advanced techniques available.

Much of the success of any hydrologi~al ~tudY,depends on the mode in

whi~h, and frequency with which water samples are collected for labora­

tory analyses. In the ~resent case a fair number of water samples was

taken from waters struck during drilling. These samples Were chemically

analysed and have turned out to be vital to the geochemical interpretation

of the Orapa ground water regime. At the time of most of the original

ddlling the lilli-son wi th the N. p, R, u, tdtium bbol;atory was no,t yet

established 80 that unfortunately only a few original depth~recorded

weter samples were submitted for tritium analysis. Hence, the tritium

studies were limited largely to samples collected after the completion

of the wells. Nevertheless, the tritium data avai.labla provide basic

information with regard to the age and degrlle of mobility pf the water

in the different aquifers. The sampling for carbon-14 I,~as undertaken

on onll special field trip only, during October, 1971. A major problem

for carbon-l4 is ~hat larse amounts of water, up to ~OO litre~. have to

be extracted by special chemical procedures in the field, in order to

get enough material for the laboratory measurement of thi~ extremely rare

i$otope. The carbon-14 mea~urements are, therefore, limil:ed in number,

yet the information they provide on the long term age of the waters and

possible underground water movement is extremely valuable. Most of the

M 4 -

d) The major aquifer is in the upper few metres of the Cave sandstone.

e) The Cave sandstone aquifer is confined and separated from the

basalt by a thin zone of indurated sandstone. The Cave sandstone

water has been obse,ved to be under artesian pressure but the

indurated ~one has been suggested to be partially leaky to water

from the overlying basalts. This conclusion has been reached

from the interpretation of the results of pump tests.

f) The possible recharge of the Cave sandstone from Lake DOlO I,aters

has been mentioned, but rejected, mainly because of lack of

supporting evidence.

g) The Cave sandstone outcrops at Serowe (170 Km south-east of Orapa)

were concluded by A.Gibb and Partners to be the rain intake area.

recharging by slow movement the Orapa Cave sandstone aquifer, This

conclusion "as based on a very generalized geological and piezo­

metric section connecting the two localities and on a salinity

gradient. suggested to occur from Ser01Je to Orapa, as based on a

small number of chemical analyses of samples, taken from wells in

betHeen the two localities. These IJells penetrate different

aquifers, so that the samples therefrom should not be compared.

All these points have been included in the present study and are

discussed in detail in the relevant paragraphs of this report. We

would like to remark here that our researches have led to conclusions

"hich are much more optimistic "ith regard to the ground water potential

at Orapa, than previously believed.

- 5 -

GEOLOGY OF THE ORAPA AREA

The General Section

The Orapa region is flat, mostly covered by sand, with pccasional

outcrops of calerete and sl.lcrete, but exposing almost no outcrop of

the underlying basalt or Cave sandstone. The lithological discription

of the rock types occurring in the substrata are, hence, based on the

examination of diamond drill cores and sludge samples from percussion

drilled boreholes.

Geological and other data for individual boreholes are summarised in

Table 1, ,,,ith more detailed information given in data sheets in the

appendix.

A typical geological section may be seen in the core log of well 2153,

located near the Orapa mine (Fig.l), and represented in Fig.2. Below

a thin Kalahari sand cover of approximately 2m, a few metres of calcrete

and silcrete, belonging to the Kalahari beds ,occur. The drill success-

ively penetrated below these, three major rock units: basalt of the

Drakensberg Lava Stage, sandstone of the Cave sandstone stage and shales.

presumably of the Red Beds stage, and undifferentiated Ecca Series.

Well 2153 is the deepest well at Orapa (325 m) and the only one that

penetrated the Red Beds and Bcea Shales. The water struck in these

latter two formations was highly saline, containing 10,586 mg/l chlorine

and 19,720 mg/l total dissolved solids (TDS). The likelihood of find­

ing exploitable water in the shaley section is small, as the shales are

most probably impermeable and hence of low potential for reasonable yields.

Furthermore, the shales are likely to contain salt and gypsum that will

salinize any water present, as demonstrated in the highly saline water

sample mentioned above. ~or this reason the shaley section will not be

further discussed and ou~ considerations will be limited to the Cave

sandstone, basalt, and Killahari beds. \,e I~auld. nevertheless, recommend

that if for any !:'eaeon deep wells should be drilled at ilny time in the

areas considered, the opportunity should be u.sed for meticulous observa­

tions for any deep water hori~ons and that samples should be collected

for isotopic and chemical analyses.

\

The Cave sandstone

The Cave sands~on" hen .. ef the mOst common rock !lnita i.n the

Kalahari substratum, as revealed in drill cores (Po1dervaart, 1951).

f>.tOrapa the CaVe sandstone haS been fully penetrated only in borehole

2153, the observed sandstone thicknp-ss being 94 m. A few surface

outcrops of Cave ~andstonp- are known near the Mopipi Dam, west of

Orapa, and along the ~etlhakane River bed. south-east of Orapa, The

drill core samples resemble the Cavp- sandstone as it is found in these

outcrops and in the extensive exposures at Serowe (170 Km to the aO!lth­

east). The sandstone is commonly fine grained, but medium to coarse

grained occurrences are known as well. The dominant colour is orange

to white. Silicio!l8 and calcitic cementations occur occasionally, a

feature that might form impermeable horizons in the sandstone section.

The quartz grains of the sandstone are partially sorted and quite well

round.ed, and it seems that we are dealing with an aealian sediment.

Both from observations in outcrops and from borehole interpretation it

seems that the Cave sandstone is frequently jointed, fractured and even

faulted, features of great importance to ground water movement.

The Cave sandstone - basalt contact

At the top of the sandstone section occurs a thin (approximately

3 m thick) zone of indurated sandstone alternating with one or more

thin basalt layers, The fact that this indurated zone with its

interbedded lava was found in all the drillings at Orapa indicates that

the pre-basalt landscape was relatively flat.

The induration of the sandstone seems to have peen caueed by lava

'contact, fol1.owed by secondary calcification.

This indurated zone seems to be of utmost importance eor the water

regime at Orapa. Water encountered in the top few metres of the

sandstone immediately belo" the indurated zone is always found to pe

fresh and always under artesian pressure. The water in the Cave sand­

stone was struck at depths of 40 to 116 m from the surface and it rose

to a depth of 7-18 m from the surface. These artesian conditions are

-, 7 -

attributed to confinement by the indurat~d sandstone lIone and by

impermeable sections of the overlying basalts.

It seems, as '<ill be, argued later, that the water in the upper

Cave sandstone is actually semi-'artesian, Le. that water can move

from the basalt aquif,er into the Cave sandstone aquifer through

occasional fractures. fault ~ones and solution channels in the

basalt and indurated ~one. This deduction is based on chemical

similarities and regional piezometric rest level fluctuations in

the Cave sandstone, all of which are discussed fl.lrther in the relevant

sections of the present ','01;k,

A.Gib,b and Pa)::tners reached a similar conclusion in that the

indurated 20ne is semi-permeable, .or "leaky". They noted in pump

tests of the Cave sandstone aquifer water excess induced by the

pumping operations, which they interpreted as leaky aquifer conditions

a11a"ing dOlmflow from the basalt aquifer.

The Basalt

The basalt, like the Cave sandstone, is one of the most ,qidely

occurring rack units in the Kalahari substratum (Poldervaart, 1951).

No .outcrops at basalt are known in the Orapa region, The nearest

extensive expasures occur at Serawe, The predominating basalt type

is massive, but vesicular variatians, partially with amygdaloidal

fillings, are known as well, mostly at the top of individual lava flows.

The ca lour is greyish to slightly purple. In several cases in drilling,

weathered basalt was encountered at the

indurated zone~ These weathered zanes

base of the section, above the

.of the basalt seem to be of high

canductance ta gl'ound ,.,ater flow. In fact, the weathering may well

have been caused by ground water in movement.

The abserv~d thickness of the basalt varies from a maximum of 110 m

in barehale 2153 to a minimum .of about 30 m in borehole 2206. These

large thicknfi)~s variations cannot be explained by Tlilference to a pre­

basalt topographic relief, as the presence of the thin lava flows

interbedded in the indurated sandstane zone at the base of the basaltic

section as described earlier,indicate a flat landscape, The thickness

- 8 -

variations can more than likely be attributed to post-basalt and pre­

Kalahari beds faulting. An example of such a fault was brought to

light by boreholes 2199 and 2206. Eorehole 2199 is located on the

down-thro,y side of a fault with Cave sandstone occurring at a depth of

82 m from the surface, whereas the near-by observation borehole, 2l25B/Dl,

and borehole 2206 lie on the up-throw side, the Cave sandstone occurring

in the last case at a depth of only 40 m.

The Kalahari Beds

The Kalahari beds at Orapa ,evesl a simple twofold Succession of

sand overlying calcretes and silcretes.

Crete (Calcrete and Silcrete): The rock overlying the basalt is

heterogeneous, whitish, with varying transitions between CaC03 and

8;02 dominancy. The term calcrete is commonly used in Southern African

literature for the CaC03 (actually limestone) variety, and the term

sUcrete is applied to the silicious type, which in most cases is

actually a quartzite. These terms, calcrete and silcrete, are useful

as they also define the mode of occurrence, i.e. in close connection

with soil, and in rather arid zones. As both end-member types have

the same colour and mode of occurrence in the field, and as mixed

complexes are common, we suggest the use of the term ~ for the

whole group and the terms calcrete and silcrate to be reserved for

chemically analysed clear-cut cases. The crete is «hitish-cream

coloured. It appears occasionally in thin layers, but is mostly

massive, boulder-like, or irregular. The crete is highly fractured

and allows free passage of «ater. The crete is the main road-making

material in the Kalahari, and is mined in small quarries. Rain water

is observed to infiltrate almost instantaneously into the crete in

such quarries at Orapa and elsewhere in the Kalahari.

The thickness of the crete at the Orapa area was measured in detail

by Mr.J.Gibson of de Beers Prospecting Botswana (Pty.) Ltd. It was

found in prospection pits to vary from 3 to over 25 ~. The thickest

occu.rrence reported from the Orapa boreholes is about 14 m in obse.vation

borehole 2185/1000.

-, 9 -

The mode of formation of the cretes is still obscure but several

theories have been proposed in the literature. At Orapa two major

mechanisms may be envisaged to have played a role in the crete forma­

tion. These are (a) leaching and surface weathering o£ the basalt,

and (b) pan deposits of the type observed at present in active pans

in the Kalilhar:L Topog;:aphically one could speculate that the

shallow Makgadigad£ depression ilt one time extended to the Orapa area,

0'"' that a simila" independent large pan existed at Orapa. Conditions

in that pan were most probably not as extremely saline as in the

Makgadigadi today, but Here such that CaC03 precipitated as is found

in the fa'; active pans in the immediate neighbourhood of Ol'apa and in the

many pans existing in other Kalahari regions.

The Kalahari sand: The Orapa area, as practically the whole Kalahari,

i.s covered by sI-llld. Thi$ "I-l"d is mainly composed of quart~ grains.

"ather ';e11 rounded and of aeo'lian origin. The colour is light brown

to light red to almost ,,,hite. At Orapa the sand occasionally includes

particles of mudstone ilnd crete pebbles.

The Band is c.onsolidated by the present vegetation - grass, Mop6\ni

scrub and thorn trees.

place at present.

Very little transport of sand seems to take

The thickness of the sand in th~ Oral'''" region was found hy Mr.J.Gibson

(personal commupicgtiop) to vary from about 2.5 m to ove;: 30 m. Thl'l

thickness of th", sand 1'~S not precisely JCecorded in the Orapa boreholes

but it seems to h<,!,'Ve been limited to a £e\; metres in most cases.

The sand is perforated extensively by the burrowing acti.vities of

mice and moles all wel1 as bigger animals. This activity causes a

constant "gardening" or ploughing effect. Experts from the Ang10 American

Corporation of South AfriCg Ltd. noted that this rodent gardening

resulted in heavy minerals from und~rlyipg Kimberlite pipes to be fOl.\nd

on the surface ",ven with a cover of over 15 m of sand (Mr.G,Edwards,

personal communication). This animal-produced perforation seems to be

of great importance in the rapid infiltration observed in the sand,

~ 10 -

Fossil Drainals Patterns

The Orapa area has an axce~dingJ.l' flat. topogrl1phy and as a direct

result no prominent river beds cross the area and run~off is not

developed in no!:mal rainy ~easons. There exists, however, a small

number of very shallow river beds, the Letlhakane being the best

example in the Orapa area. These river beds are seen on air

photographs but in the field they are hardly discernable and can go

unno dced. In the heavy 1967 rains, the Letlhakane is reported to

have carried water for two or three days, which is regarded as ex­

ceptional (observed by H.T.Jones, Bots"ana Geological Sllrvey),

The existence of these faint, but occasionally still active,

drainage systems might have some bearing on "ell siting, In fact.

the ,.,ells in field 2 are close to the Letlhakane dry river bed and

wells 2199 .and 2206 were placed almost in the old dver bed in the

hope that 'recharge would ba

the best yielding boreholes

locally enhanced.

so far drilled at

These two wells are

Orapa. In addition

to being sited in the Let1hakane river bed, they also flank a fault.

It is as yet hard to estimate the degree to which each of these factors

influence the hi.gher yield of these boreholes.

It could, therefore be recommended that points sitllated on dry

river beds should be given preference for future well siting, in

addition to the other considerations to be taken into account which

are summed up in a later section.

The existence of these old drainage systems has been described by

various investigators as reflections of past periods of different

climatic conditions in the Kalahari, distinguished by heavier rains.

withollt directly disproving these paleoclimatological theories, it

seems that another explanation may be offered. The Kalahari under"ent

a continuous levelling process in recent geological periods, "hich led

eventually to the present flatness. A direct outcome of any levelling

process of the earth's sllrface is a constant slowdown in the flo" of

run-off Hater, and the filling up of existing rivers leading gradually

- 11 -

to their going out of commission. It might well be that the shallow

and rare dry river beds found in the Orapa region are in fact faint

left-overs of the peneplanation activity in the Kalahari and he of

no paleoclimatological consequence.

Joi~ in the basalt

In aerial photographs and hy direct observation of the Orapa region

from the air, a host of linear features is seen. These are mainly

lines of denser vegetation clearly visible on the sandy background.

These lines can hardly be features in the Kalahari beds but seem to be

surface expressions of open .Joints in the underlying basalt. The

width of these lines of denser than average vegetation varies from a

few metres to about 10 m and their length from a few hundred metres

to several kilometres. The lines show local parallel orientation in

lines. Occasiopally two such sets of lines intrarsect. It seems that

the plants find hetter growing conditions along the joints in the

basalt, probably because their roots can penetrate deeper and because

rain recharge is concentrated in these joints.

These joints, outlined by the vegetation, seem to be pf great

significance to rain intake at Orapa, a point which will be discussed

later.

Doleritic Dykes

Another type of linear feature is that of post-Karrea doleritic

dykes, found in many areas in the Kalahari. An example of such an

intrusion (though not linear) is seen at the Mskgaba springs and

shallow wells, located 100 Km NNE of Orapa. The water in the springs

and wells is available at the surface due to these doleritic bodies

that intersect the Cave sandstone and form water collecting barriers.

At Makgaba one small spring and several very shallow hand-dug wells

provide excellent water with about 100 mg/l chlorine and 700 mg/l TDS.

Many beautiful examples of doleritic dykes, intersecting Cave sandstone

are to be seen at Serowe. These are directly responsible for little

- 12 -

sprinl:;s and make site~ for excellent wells.

The extent to which doleritic dykes occur at Orapa is hard to assess

but it is likely that part of the more prominent linear features marked

in the area by the mar", dense vel:;etation are actually doleritic dykes.

It is strongly urged that the possible existence of post-Karroo dykes

at Orapa be studied, perhaps even by geophysical methods, in connection

with any future bor"'hole sid.ng at Orapa.

TABLE 1: Boreho1e Profiles and Tested Yields

"Field No.

Well Kalahari Basalt No. Beds*

I·

1

2

2118

2130

2144

2152

2153

2174

2175

2179

2193

2182

2183

2185

2185/ 1000

2198

3 2199

1-11/_2~~6

m m

0-3

0-3

0-3

0-3

0-3

0-3

0-3

0-3

0-3

0-3

3-116

3-104

3-119

3-101

3-113

3-110

3-114

3-105

3-104

3-87

0-6 6-87

0-14 14-114

0-17 17-69

0-5 5-59

0-9 9-85

0.12 12-40

, """ "" """"--"--.. ,,------, Cave Red Beds.: Yield:

Sandstone & Ecca" m3/d i m In I

116-130

104-128

119-137

101-129

113-204

110-128

114-125

105-142

104-137

87-123

87-117

114-139

69-98

59-99

85-132

204-325

60

90

80

160

160

150

90

110

110

220

130

130 ! I

130 " I

130 I 160 i

I I. 40-108 !

1. __ .. .. I

320)

* The thickne~s of the Kalahari Beds in the first ten wells of this

table has unfortunately not been recorded while drilling. The

figure of 0-3 m is a minimum estimate.

- 13 -

HYDROLOGY

Location of walls and boreholes

During 1968 and 1969 thirty-t~1O boreholes warl! drilled at,Oral'a,

twentrseven of which have been equipped and pumped (fig.l). The

boreholes are distributed in groups; one group is at the mine (Well

field I), a second is 14 Km east of the mine (Well Field 2) and a

third is 20 Km ESE of the Orapa mine.

or near the Letlhakane dry river bed.

The latter two groups lie in

In addition two wells were

operat.ed at the township" Two former existing shaUow wells. one a

hand-dug "ell at the landing ground, 8 Km north-west of the mine, and

Steinberg's borehole, 12 Km north-west of the mine. have been included

in the present study.

Tested yields and abstraction figures

Upon completion of each well the Geological Survey made a pumping .~An i'o/l ' ;Y'"

test and determined the yield (Table 1). The average tested Yield~ J/-0'

for each of the three well fields are summari~ed in Table ~V~~y~,~,/ ~,A fl/I 110-" \ ~ tX:-J::/X:;VjV, ' ~ CO'\

TABLE 2: Tested Yields ---/~ (J f.,r" , ..

Well Field No. of working Total tested yield

wells of field*

950 m3/d I

1 12 ,I

2 6 750 " li I

3 2 500 " i ir

, " ~.~ 3 .~ '0. r Total 20 2100 !lI3/d I "

I .. , 'i

* The yields were determined pumping a day. ,

tested for ten hours The

I yield from each field was estimated by summing up the tested yield

of the individual wells (m 3 /h, Table 1) • multiplied by 10. I

The amounts of water actually abstracted were carefully estimated

by officials fT.'om the Diamond Research Laboratory.

are given in the. sec.ond column of Table 39

Their figures

Table 3: Abs.traction percentages from the combined Orapa well

fields

Fraction of tested [--~:ar- '-T--~~~tr~;;~~~-s---

------ -- -------- -1--------- -- -- -- .-. ----' yield abstracted ~ • loJJ((.:2-

1968 I 100 m3 Id 10%

1969 I nO" 30 % J

l 1970 I 570" l mid -~~~_. _____ . __ J _____ .~~_~ _____ . __ ..

Well field 1 "as pumped from th.e beginning

50 %

60 %

of 1968 until August, 1970.

Well field 2 was in use from May, 1970 to mid-1971 and Well field 3 was

exploited from August, 1970 to mid-1971.

The amount of water abstracted from the fields 2 and 3 together (first

only field 1, then fields 2 and 3 together) each year (Column 2, Table 3)

and dividing by th.e tested yield of the fields, (last column, Table 2),

and multiplying by 100, one gets the fraction of the fields' tested yield

actually used. The results (last column, Table 3) show that at no stage_

of the ground water operations were the wells pumped to full capacity.

Field 1 was pumped only 10% of its full capacity in 1968, and 30% in 1969.

Fields 2 and 3 were pumped together to only 50% of their capacity during

1970 and 60% in the first half of 1971. The heaviest abstraction took

place during the first half of 1971, namely 660 m3 Id, but this was using

fields 2 and 3 only. The tested yield of all three fields together is

2100 m3 Id, Le. three times higher than the maximum abstraction of 1971.

The conclusion that the <Iells at Orapa have been exploited far below

their full capacity is well supported by the relatively small drawdowns

of the water table rest levels observed during pumping, and also by the

rather short time periods that were needed for complete rest level

recovery after cessation of pumping.

discussed later in the report.

These observations are presented and

1 5' (:0-7 -

\

TABT,>=: 4: CAVE SANDSTONE REST LEVEL DATA

IField Well Dep-th Depth? water struckjo .. I I * _._- -.--.---' ~*--l-':--'~"-'----'--"'--- .':-- r ··-------·-1 i;cc.;verY'

metre rlglna r .. New r.l. before pU<:lplng M~nlmum r.!. due to pump:mg Recovered r.l. , . I 1. No. No. of , I tllr.e, I

Well

I I

Basalt I Cave Sandstone I Depth .1 Date Depth I I Depth I I Depth 1 i months i Metre Metre metre Date I metre: Date };etre Date

1 2118 130 24 115 IL9· before I

5/68 16.6 5-/70 11.6 2/71 i 10

2130 128 104 14.3 " 16.3 5/70 11.6 2/71 ,

6 i 2144 137 119 15.0 " 16.6 5/70 10 .111 5/72 I 11 I 2152 129 18 107 f 11.9

" 15..2 1/70 11.6- 2/71 I 11 I

2153+ 325 19 114 16.2 4/68 - 1/69 24.4 10/69 , 12.2 8/71 10

I I 2174 129 110,128 16.5 before 11/68 22.9 5/70 12.2 5/72 , 12 I

I before I I 2175 126 116~1l9,,-124 15.2 " 10/68 t2~2 12.2 4/72 i I 2179 141 110,116,,134 lS.6 " 10/68 18.1 5!7Q 12.2 10/71 f II ,

2192 18 I 22.4_ 5/70 14.0~ 4/12 ! 12 I i 131 116 .. 128 , 14.6 I

i I ! i 2193 137 15 lOS .. 113.,129~135 i 14.6 " 11/68 20.5- 5/70 9.U, 4/72 I 12 . . r-. .

1 2 2182 123 27 90 i 16.2 " 12/68 14.0 before 1/69 i 2183 117 13 87 12.8 " 9/68 10.1 .. 1/69

I • I

1 " 10/68 10.6 " 1/69 I

2184 102 68 10 .. 4- I i I ,

2185 139 68 ! 10.4 " 1I/68 15.3- ~ !lo9

I I 2185/

98 I

8.2 7.8 ZO .• & 1l.2A ,

I . I lOaOt I , " un 12.96. 4/72 I 8 I . 2190 91 27 LL9- If.9, 21.<l

2198 99 27 12.8 n 1169 8.9 ,

1169 14.9- Int i I - ---_._------ . ""-----~~.-.--- .. ~ .- .. ------~, .... -.-.-........ ~ .... -.. .. [ .. - I 3 1 2199 I 132 12 98 9.2 .. 2/69 8.0 " 7/69 g&3'" 4/72 12

1

2206 108 23 108 I 7.0 n 21.9 , 7.2' 4/n I 12 I

I I I I i 12125t I 6.4

, 14.5 , ____ .J 8.lA I .. J ! L_ , I .. _---_ ..

* The artesian rest level up to which the. wa.ter rose after drilling into, the Cave sandstone.

** In fields 2 and 3 the rest level went up before p,umping started .. most likely due to regional recharge from the. 1967 rains.

obscured becaus~ it was pumped at that time (text).

In field 1 this was

t Observation borehole.

t:. Still rising at time. of last rest. level measurement (Data sheets- in Appendix).

Single measurement.

~ 15 -

The present water requirements at Orapa are 400 m3/d for domestic

consumption and up to (fOOO m3/d for the plant requirements, a total

of 4400 m3 /d. This is only twice the tested yield of the existing

three well fields.

The Diamond Research Labo;;atory officials estimate the peak need

for water for Orapa in the future to be, at most, twice the present

consumption. This will be 8800 m3 /d, ',hich is four times the pot­

ential of the existing wells.

Some ,·mys in which Orapa "'B.ter requirements may be met by local

ground ,,,ater supply, "ill be treated in a later chapter. We would

like to mention here that in this report we put forward suggestions

for "ater reclamation in the plant that may eventually lower the

maximum future joint domestic and plant consumption to about 2000 m3/d,

which is in the order of the tested yield of the existing wells at

Orapa.

A b",si:"-3!:J~.!:'me,,!c~hat l.\?_derlies. ___ 0y.r.Jea~oni!l~s __ tha~ the Orapa

wells are no<, shown to. be re1iIl:~:Y~"1'1."11jsl~-"_~~_!,'!?~!l\ll:ln,:~iE-I~s!J_"lrge

so that th'!.Y __ ~:iLLJ-"nctiol~ __ ,,-te_iidily ,_Tl1_i.~_p(?_i~t Js __ examined late~

in J:hiii.EP.()E!:.Li'Jl1-".," __ L~_._ll:l'p_"aEs_ to be ELI1,E!IV ___ .c2_11,c:1(jsJol1,_!'''-l:_thistyp'e

of e~~iro~~e~_~ ~

Rest Level Obaer~ations .~,..."

The various t"!lst l"ve1. Ob$el'vations "re presented in Table 4 and are

plotted on the individual 101ell data sheets (AI to A28). The information

gained from these data is interpreted as follows:

Regional dse in the C§lve sands.'=2ne. res t level: The odginal lO'est

level to which the Cave sandstone water rose in each bOJ:ehole while being

drilled is given in Table 1. A comparison of these figures with the

rest level measurements taken in fields 2 and 3 during 1968 shows a

systematic rise of an average of 1.8 m (hydrographs on the well data

sheets in the Appendix and Table 5), Thereafter, the ",ells "ere pumpli'd

and the rest levels ",er.e disturbed. In well field 1 this rise could

not be observed initially as pumping operations started immediately.

~ 16 ...

However, th~. recovered rest levels observed, af ter pumping was stopped

in field 1, are systematically higher than the original rest levels by

about 3.5 ill ·as observed up to 1971 (data sheets in the Appendix).

~R-e-s-t--1-e-v-e-l-r-. i-s~e--l~' ~~~~ up -~~- 19'--7-1--------.... 1 -3-.-5~m---, I

Rest level rise in fields 2 and 3 during 1968 I 1.8 m

Naximum relative dra",dmm from the surface 119 m

Time of rest level r",covery after cessation of pumpingl 10 months

A general ri$e in the Cave sandstone piezometric level is therefore

observed. This rise is around 3.5 m in ",ell field 1. for the period

1968 to 1971. In fields 2 and 3 the observation period was confined

to 1968, and for this time a rise of around 1.8 m was recorded,

This observation, that the Cave sandstone semi-artesian rest level

fluctuates significantly, can be understood by it being open to the

phreatic Kalahari beds aquifer .and together with it is responding to

variations in the rain recharge. In the present case we might well

be observing the influence of the heavy 1967 rains.

reCharge mechanism is proposed in this report.

Relative rest level drawdown durin!? !?umrin&

A model for this

Rest level m"asurements were taken during pumping periods in observa­

don boreholes. as well as in neighbouring (temporarily non-pumped)

wells. The results are plotted in hydrographs induded in the Hell

data sheets, in which the period of general exploitation pf the relevant

field is marked by a bar at the top of each hydrpgral'h, From the data

it was possible to find the minimum recorded rest levels (Table 4, column

10). By comparison with the rest level before the commencement of

pumping ("ell data sheets) the maximum relative drawdown may be found in

each case, The maximum relative dral<ldown in the three well fields was

2 to 12 m with an average value of 5 m. Taking into account the general

rest level rise during this period, say 3 m, the effective relative draw­

down is about 8 m (Tahle 5),

- 17 -

A drawdol'U of 8 m is commonly regarded as a very modest figure, a

few tens of metres being more common. To emphasize this point we may

quote that in the A.Gibb and Partners report, the estimate for a three

year water exploitation was based on relative drawdol'Us of up to 80 m,

i.e. ten times more. Thus it seems that the well fields have been

pumped substantially below their safe yields. This supports our

earlier conclusion from the comparison of the actual abstraction figures

with the estimated yields derived from pumping tests. In the light of

the low drawdo<ms observed it seems t.hat these pump test yield estimates

of the Botswana Geological Survey (Table 1) were conservative.

Absolute. .. rest level dra",down during pumpinll

The lowest recorded rest levels during pumping are on the average

19 m from the surface (Tables 4 and 5), the maximum recorded being 24 m

(observation boreho1e 2153). In order to evaluate whether this average

figure is high or low with respect to a maximum permissible value, let

us take into consideration that the pumped \Vater rises in a semi-artesian

mode from the upper part of the Cave sandstone aquifer. The depth to the

top of the Cave sandstone varies from 40 m below surface (Bh 2206) to

116 m (Bh 2118), as may be seen from the data in the Appendix, the aver­

age depth being 100 m. Should an a priori safety limit for drawdolVll be

decided upon, it would most likely be a few metres above the top of the

Cave sandstone, Or at the contact. Thus the average dra"down of 19 m

from the surface reached during pumping at Orapa is far from the maximum

permitted value "'hieh on this line of reasoning would be about 95 m

below surface.

The conclusion may, therefore, be reached, also on grounds of the

absolute drawdown figures, that the Orapa wells may be significantly

more heavily exploited in case of necessity.

Time of rest level recovery after termination of pumping

From the hydrographs (Appendix) the elapsed time from te~mination

of pumping in each field to the full recovery of the rest level in the

individual wells may be read. This time is given in Table 1, and is

seen to vary from 6 to 12 months, the average value being 10 months

- 18 -

(Table 4), which we can regard as rapid. The recovery time could in

certain cases be deduced only approximately because of the superimposed

regional rise in the water table described previously and, in a few

cases, because the time elapsed since cessation of pumping was too brief

for accurate observations.

The fast recovery and the high degree of complete restoration indicate

again that the amounts of water abstracted were indeed small compared

"ith the potential water volumes. It indicates efficient replenishment,

not only by lateral flow in the aquifer, but most probably also by direct

rain recharge.

The short recovery periods observed lead in addition to and independ­

ently of the earlier considerations, to the conclusion that the Orapa wells

are reliably replenished by rain water and safe for pumping periods of

many years.

Number of water horizons in the Cave sandstone

A.Gibb and Partners reached the conclusion in their report that the

upper few metres of the Cave sandstone are by far the most important

water-bearing zone. This conclusion was based on resistivity logs

that showed only minor additional water horizons in the deeper parts of

the vdve sandstone.

The drilling information available indicates however that several water

horizons were encountered in the Cave sandstone (Table 4, column 5).

Examples are boreholes 2174, 2175, 2179, 2192 and 2193. In these, water

horizons were encountered dOl~ to the final depth of the well. It still

remains an open question as to what extent these additional water levels

are of quantitative importance.

Another way to assess the potential contribution of deeper Cave sand­

stone water horizons is to plot the tested yield of the wells as a function

of the depth of the Cave sandstone section penetrated (Fig.3). A pos­

itive, though rather poor correlation is observed. This type of plot

has the tendency to show a poorer correlation than really exists because

a host of other factors are superimposed upon the parameter of depth of

penetration into the Cave sandstone. These other factors are topography,

~ 19 -

fault structures, thickness of the basalt column, etc. It seems,

therefore, that the poor, but positive, correlation seen in Fig.3

might be indicative in fact of a more pronounced correlation, meaning

that the deeper water horizons in the Cave sandstone are of possible

importance for abstraction.

It is, therefore, recommended that the deepening of wells that

ended in the upper parts of the Cave sandstone be one of the techniques

to be applied for the development of existing wells. A list of such

techniques is presented. later. tn new boreholes, it will definitelY

be worthwhile to penetrate most of the Cave sandstone section without,

however, penetrating the underlying Ecca shales with their potentially

highly saline water.

The Semi~artesian character of the Cave sandstone aguifer . '. _._, , x. _.'" ,.

Once the drills passed through the basalt and entered the Cave

sandstone, water was encountered in every instance. As discussed

earlier, the water rose to near the surface, the original rest levels

being given in Tabb 4 (column 6). It is thus clear that the Cave

sandstone aquifer is confined by the indurated zone and impermeable

sections of basalt which constitute ;:he top of the sandstone.

On the other hand, a large number of observations indicate that the

Cave sandstone aquifer is actively recharged by local rain that infil­

trat.es into the Kalahari beds, traverses the basalt, probably mostly

along joints, and enters the Cave sandstone by passing through the

indurated ~one. That such a recharge takes place \<66 borpe out by the

rapid and complete rest level recoveries, after the cessation of pumping

and the fluctuation~ observed in the re~ional Cave sandstone pie~ometric

level, which in recent years seems to have responded to the heavy 1967

rains. The chemical data is shown in a later chapter to agree with

direct !'echarg" of rain passing through the Kalahari peds and basalt,

apd entering the Cave sandstone. I

One is, therefol?e, confronted with an appar.ent contradiction, namely

that the indurat!'ld ?:one and basalt confines the Cave sandstone \;ater and

at the same time lets descending rain water through into the Cave sand­

stone aquifer. The way out of this dilemma is by postulating that the

(ll

l

- 20 -

indurated sandstone is impermeable but bisected by occasional joints,

faults and solution channels which form isolated hydrological links

with the more superficial water horizons. A schematic portrait of

this leaky semi-artesian aquifer, is given in Fig. 4. In other words,

the artesian pressure in the Cave sandstone is caused by the phreatic

water head, which in most cases seems to be in the Kalahari beds. This

is supported by the fact that the Cave sandstone water rose in the

boreholes to 7m - 18 m from the surface, i.e. just in, or near the

range of the Kalahari beds water level.

- 21 -

GEOCHEMICAL COMPOSITION OF THE GROUND WATER

Nature of the available data

Chemical analyses are available for twenty-two boreholes and wells,

spread over a radius of 20 Km from Orapa. Each well has been sampled

and analysed several times, providing three types of sample material:

1) Samples collected during drilling, giving a classification of the

nature of the various distinct water aquifers, i.e. the shallow

Kalahari beds water, the basalt aquifer, the Cave sandstone aquifer

and the deeper Ecca and Red Beds water.

2) Depth samples taken in non-pumped wells with a special depth

sampler. In spite of previous fears that the sampler might mix

the water column in the well, water stratification was observed.

3) Samples collected repeatedly from pumping wells, supplying in­

formation on the extent of change with time and hence also with

water abstraction.

Altogether 227 analyses are available. The dat.a are given in the

well data sheets in the Appendix in the form of mg/l (milligram/litre)

and meq/l (milliequivalent/litre).

Major water types at Orapa

At Orapa the following major water types occur in downward sequence:

a) Shallow Kalahari beds water: relatively high in NaHC03' (800-1000

mg/l HC03) and low in NaCl (about 80-200 mg/l Cl). This water

type is represented in the Steinberg bore-hole, it was found in

certain seasons in the Landing Ground well, it was encountered

during drilling in boreholes 2130 and 2199 and might have con­

stituted the water sampled in the Township horehole No.IO, after

April 1970. This Kalahari beds water type seems to be rather

common but it might not have been noticed during the drilling

operations as the major expectations for water would be from the

deeper aquifers.

- 22 -

b) Basalt water: this varies in its Cl content from 580 to 4400 mg/l

Cl. The low Cl content water, found only in boreholes 2174, 2175

and 2179 (and questionably in a few others), resembles in its com­

position a mixture of the overlying Kalahari beds water with the

more saline type of basalt water. The saline basalt water (above

800 mg/Cl) is tagged by the dominancy of the Cl among the ions, the

major salt being NaCl. These saline basalt "aters ".ere struck in

borehole 2153, 2179 (in one sample) 2190 (one horizon), 2206 (one

horizon), and 2199 (nine samples, "ith one fresh horizon in bet"een).

The basalt is. therefore. a heterogeneous aquifer in which "ater is

struck occasionally, presenting a whole spectrum of fresh to saline

"aters.

For measurements taken at specific depths with a depth sampler in

various wells a year or so after their completion no saline "ater

was encountered even in those sections that had upon drilling

yielded saline water. Examples are boreholes 2190, 2198 and 2199.

It seems that the rising fresh Cave sandstone water flushed out the

basalt saline water in the vicinity of the borehole.

c) Cave sandstone water: this water is relatively fresh, average TDS

of 1200-2100. The Cl content is 400-600 mg/l and the RC03 content

is 400-800 mg/I. Na is the dominant cation.

d) Red Beds and undifferentiated Ecca "ater: borehole 2153 is the only

one that was drilled through the Cave sandstone into the underlying

Red Beds and Ecca shales. Only one "ater horizon "as struck in these

shales and it contained 19,720 mg/l TDS, most of it being NaCl. A

convenient probe to the major Orapa aquifers, with the exception

of the Kalahari beds, is offered by the deep (325 m) borehole 2153

(A-7) •

Compositional Relationships between the Kalahari beds, basalt and Cave

Sandstone waters

The water in the shallo" Steinberg well is rain "ater which has in­

filtrated directly into the Kalahari beds. This is suggested by the

- 23 -

flat topogr!1phy that rules out any underground flow in such shallow

depths as the Kalahari beds. The shallowness of the ,,,ell is borne

out by

of the

the observable salinity fluctuations and the elevated value

tritium content. As mentioned above, this water type is

characterized by low Cl contents (100-200 mg/l) and by NaHC03 dominance

(1100 mg/l HC03). The same water type has been record-ed from bareholes

2130 and 2199 and it seems to be one of t",o components in the Landing

Ground well.

The HC03, or the C02 that served to form the HC03, must have been

picked up in the passage through the thin soil cover. This is supported

by the remarkably high C-14 content (86 percent modern carbon, Table 6)

"'hich makes it clear that one is not dealing with dissolution of a

carbonate rock (old). but with enrichment from biogenic C02 "'hich can

originate in the soil cover alone. The fact that the balancing cation

is Na and not Ca is very interesting, and further study is required to

explain this pattern. We would like to note here that water of the

same composition is found in the very shallow water wells in other

Kalahari regions.

The Landing Ground well (A-2) sho",s remarkable salinity fluctuations.

Three samples are low in Cl and high in NaHC03 and are of typical

Kalahari beds composition. Four samples are high in NaCI and are of

typical basaltic composition. In addition the tritium content is high

and varies greatly. This well is shallow, dug through the Kalahari

beds and a bit into the basalt, which here is rich in NaCl. It seems

that during seasons in ,,,hi ch the well is full the Kalahari beds water

dominates, but when the water level drops it is the basalt water that

dominates.

The composition of the water in the basalt is readily explained as

Kalahari beds water to which salts have been added in varying degrees.

This is seen from the chemical composition diagrams of Figs. 5 and 6.

All the ingredients present in the Kalahari beds water are present in

the basalt ",ater, ",hether fresh or saline. The basalt waters contain

HC03 in amounts similar to the Kalahari beds water, slightly more K

and significantly more Na, Ca, Mg, Cl and S04' Thus, the ions in excess

over the Kalahari beds content may be regarded as additions from the

- 24 -

basal t. The dominance of NaCl in the basaltic additions calls for

discussion. Basalts contain Cl as a trace element only. Hence, the

NaCl cannot originate by leaching or weathering of the basalt. It must

ha.ve been brought into portions of the basaltic aquifer some time after

the outpouring of lava. Former pre-Kalahari beds pans and inland lakes

are one possibility of such NaCl accumulation but no unambiguous solution

has as yet been given to the problem.

The Cave sandstone water also contains all the dissolved ions from the

Kalahari beds water but with small additions of the ions that typify the

basalt water. In Figs. 5 and 6 the composition of the Cave sandstone

water is seen to be between that of the Kalahari beds values and of the

basaltic values on the Na, Ca, Mg, Cl and 804 diagrams. Thus, the Cave

sandstone water seems, from a compositional point of view, to be Kala-

hari beds water with slight additions of basalt water. This is in

excellent agreement with the hydrological regime portrayed above for

Orapa. The Kalahari beds water descends into the basalt. There, in

stagnant sections, it becomes highly salinized by additions of Na, Ca,

In jointed zones the Kalahari beds water moves down

faster and as a result only small salt quantities are added. In this

way the fresh waters occasionally observed in the basalt are formed, and

represent mainly the Cave sandstone type waters as no significant changes

in its composition occurred.

Degree of compositional uniformity of the water in the Cave sandstone

aquifer

The composition of the fresh Cave sandstone water in the different

wells varies in repeated samplings - as is seen in the well data sheets.

In order to get an overall picture the average compositions were found

for each well (Appendix) and from these the average composition of each

of the three well fields was obtained and plotted in Fig. 7. The

composition of the three well fields is seen to be almost indistinguish-

able. The compositional fluctuations in the individual wells are, thus,

larger (Appendix) than the differences bet«een the well fields.

This similarity in the composition of the waters in well fields 1, 2

and 3 indicates that the Cave sandstone aquifer is homogeneous, at least

over the stretch of 20 Km studied.

- 25 -

The compositional fluctuations represented by the Cl content in the

water of the various wells have been plotted against the sampling date

in Fig. 8. The period during which each of the well fields was pumped

is indicated in each case by a bar along the data axis. The fluctua-

tions in the Cl content are seen to be random and reveal no correlation

whatsoever with the main pumping periods. The Cl content is, within

certain limits, constant over the whole period of study.

The compositional constancy of the Cave sandstone water seems to

indicate that the storage in this aquifer is large as compared with the

amounts of water abstracted. No neighbouring water body was significant-

ly drawn in, i.e. neither the very highly saline Ecca shales water from

below, nor· saline basalt water from above. This is again in good

agreement with the conclusion reached in earlier parts of the present

report that the Drapa wells were abstracted well below their safe yields.

- 26 -

ISOTOPIC STUDIES

Nature of Tritium and Carbon-l4 as hydrolo&ical parameters

Tritium is a heavy isotope of hydrogen (indicated as 3H or T). It

is radioactive with a half"Ufe of 12.3 years.

Carbon-14 is a heavy isotope of carbon. It is also radioactive.

with a half-life of 5730 years.

Both isotopes are formed in nature by the reaction of cosmic rays

with nitrogen in the upper atmosphere. The tritium is oxidized to

water and, thus, rain water is tagged by·nature with tritium. The

concentration of tritium in water is expressed in terms of "tritium

units" (T.U.), defined as the concentration of one tritium atom per

1018 atoms of the light hydrogen isotope (I H). The average concentra­

tion of tritium in rain water from natural sources before H-bomb tests is

about 5 T.U. in a continental environment. The carbon-l4 atoms are

oxidized to CO2 , which is partially bound in plant material. The con-

centration of carbon-14 with respect to common carbon-12 is expressed in

relation to an international standard, assigned as"lOO percent modern

carbon" (lOO pmc). Rainwater becomes enriched in C02 while passing

through the soil cover, this C02 being of biogenic origin and, hence,

containing carbon-14 in atmospheric concentrations. On its way through

the unsaturated zone and during its residence in the aquifer ground

water loses some of its carbon-l4 due to reaction with limestone rocks

devoid of carbon-l4. It is now commonly accepted that due to these

processes recent ground water contains about 85 pmc.

The analysis of tritium and carbon-14 is done in highly specialized

low-level counting laboratories as the concentrations involved are

extremely low and the beta radiation emitted by the decaying nuclei

is of low energy. For tritium, half-litre water samples are sufficiently

large, but for carbon-14 a sample of up to 200 litres of water has to be

treated in the field to extract enough carbon for the analysis.

Since the inception of nuclear bomb tests in 1952 both artificial

tritium and carbon-14 have been released. Their concentration in the

atmosphere, and hence also in rainwater has gone up significantly. The

rise in the tritium values in rain is summed up in Fig. 9. The values

Table 6: Tritium concentrations in i.U. at different sampling dates

.. _ .. ;----- .. - ---1 - - .. - --- .-._.-. -.---.-.. ---.--~~-.

Borehole i 10/6B: 3/70 i 5+6/70 8/70 10/70 ;-_.:- ... -... -.-~ -~---";"""""---~-.-._t-... -.- .. . .n •• ,.. : _. ____ •

:Stelnberg's i ! 2.9±O.3 4.5±0.4 3.8±0.3 i 2.9;2.2 '-"",,, ",-,-4----,--'-- '" " 1.3±0.3 [Landing Ground, i 22.5±1.3 31.310.8 8.StO.7:

2/71-- --'4/71

0.7±0.2

20.310.6

5/71 0.8i ()':2

13.4±0.5 '_, _"wel} .. , ___ , __ ---,1-"" ,,13.4± 0.6 _. __ , __ ,,_'''j ____ , __ , -.,' ,_'''' _, ___ , ' __ "'-------,, ,. i Townshlp No. 9 : I 1.0±0.3 1 1.4± 0.3 i j i *0.2;0.4;; : i· , i I i 0.2'0.11 I Townsh'ip-No.ib'T----11. 3±O. 3-r- o. 9±(L:n-----l-----'------;------·--', "~ ! . : ! : 1 j l 1 rm. 8-'.------1' ~-----l--'{)·s ±O: ir-2.8± 6: i 1 i: Ot'O :'3'1'- ---- r i \.......... .. -.. I -+-_ .... _-.- .... --.•..... ---.-- .... ··.·-.·.··--,.-_····--·7-·· -- .. -. --., .... --- .. - •. ~ .. --- .. -.-.- ... -. ! 2144 ' ! 1.7±O.3 : 0.7±0.3: 1.7±0.3 0.9±0.2 : 0.S±0.2 : 1 l' , i ' 1 215::2-----'--- - 1 0~8±O,.2 3.3±{).4 1 i

i 2174 -+--,----:""2 B':':'O""3,1 '1"2+0 3-- 1 '--1'6'.0 '2- c, 0' '1+0' :5 i'D' '4+0'2"-"" '-''''--i I .- .. -. I .-. ' .-. 1'-': L-...... - ... ---",,-_. ______ .. ____ .----.; .. ___ . -. . _ .. _ _ _ .. _. L _. _.. .. -......... -_.. . - .-. - .~. =t- .. -~-i 2175 1.1 ±O.2 1.8±0.3 i 0.9±0.3 I 1.0±0.3 0.4±0.2 0.0-0.1

i . I

:; : i [2179------ i" '--~ ----,-, - --1.7±0:'3 '1"----'-1'---' ----- 'O.0±0:2' 'o.O±O • .1 t- -- ... , .-----.--.- . ......L. .. ____ -- -. ----f ----.-. -+. -.- -, ---- -. ---+. .' --.-.-... - .... _--:;:- .... --.. -.-r- ..... _.-. "+ ___ no •• ---•• :----. + - ± _. -- ..... --._. ± LI82 _0.3±0.-2-1_, 0~6-0'~ __ j _1._1-0.2 j 1.1-D.3

1 2.0-0.3, ,: __ 0.7-0.2 , 0.4+0.2" _,O:~. 0:2.

12183 2.2+0.5' 1.3±0.3 2.0±0.2, 0.7±0.3 1 '0.8±0.3 i 0.S-0.2 0 . .:>-0.2, ! i 1_ ! i I • - -- _. --"--~.------ -'--'T-' -_ .. +----_.-- -j --.'---- ..i. - .' .--+-----.+ -. i 2184 , 1.7±0.4 , , 3.5-0.3

1

1, . .2-0.3, 1.6-0.3 , I! I 1, 12185 ---,---, 1

1

--'] 1'2. 7i6~3 '2.0;:0:3 'I - 0:8±0:2-,' "'O.4±0:'2' i 0.0±0.3 ! ; I ; 1

:89,,=~_' ~~' '! _i I *i:~;L 7; 1, ',", -, ~,L____ ___ .______ ," ,. +'.

: 2190 • ! 0.8±0.3 ! ! 0.5±0.3 I 0.2±0.2 : 1 0.1-0.2 : \--- .• - ___________ i.... _____ ------------. ___ ... . - -----~ -_. - -, - ------.- .• -t--.-------. . -f ., .;

j 2193 i 'I 1.1±0.3 I 1.8±0.3 1 '0.5'0.2 : I 1 i : 1 r2i.9if . r--- "'1"'*1'.4;2.4; j *2.3±0.3 '0.1±0.2 , 0.,6±0.2 j '--""_, .. , __ 1,,, .. ,,,,,,,.,,,,_1 1.1;1.8 I 2.4±0.,3! '''''' '" , ,i ," + "+0 ;

~199 _______ 1" ______ JJ~;~:i; l' *~:i;2_~4;l , __ J 2.2±0.2 , 0',7±0.2! 0.4:0.2 0.4: .2j

1_2_2_0_6 ________ 1 L:.Li,:g:L :3.3;1.9L~5_;_I_._2 _I_._6±0',= __ , __ ~_~±_0':.J_O_ •. 7~~~ 1_ ,O~~_~:,~

0.3±0.2 {).3±0.i'" 'b.o± O~ 2',

O. 7±o~i

"Depth Profile

- 27 -

rose in the southern hemisphere from about 10 T.U. in 1955 to almost

60 T.U. in 1963 and then went down to about 30 T.U. at present. The

carbon-l4 concentrations in rainwater in South Africa were around

120 pmc (percent modern carbon) during 1960 and 1961 and rose up to

160 pmc in 1965 (Munnich and Roether, 1967).

The tritium content in 1952 rain water was about 5 T.U. and the

tritium in ground water recharged that year has decayed to about 2 T.U.

at present. Thus any tritium value above 2 T.U. found in ground water

indicates post-1952 contributions. Similarly, any carbon-14 value

higher than 85 pmc most probably indicates a post-1952 component, a

conclusion which is true beyond any doubt if concentrations of above

100 pmc are observed.

Tritium and Carbon-14 results at Orapa

The only depth-documented samples collected during drilling operations

that were submitted for tritium analysis are from Borehole 2153 and

samples from pumping tests after borehole completion were submitted for

boreho1es 2104, 2182, 2183 and 2184. None were sampled for carbon-14

at drilling. An important body of potentially valuable information is

therefore not available.

These earlier samplings were of an exploratory nature, submitted

through Mr. C.M.H.Jennings. then at the Botswana Geological Survey,

before a working liaison with the N.P.R.U. had been established.

The main body of material studied was pumped samples with some occasional

samples collected with a depth sampler in non-pumped boreholes. Altogether

over one hundred tritium measurements were done on samples collected in

1968, 1970 and 1971. The individual results are assembled in Table 6

and given along with the chemical data in the tables included in the well

data sheets in the Appendix.

The results for the most frequently sampled points in the three pumped

well fields sre summarized in Fig. 10. The following features can be

identified therein:

a) Fost-1952 tritium contents are clearly observable.

- 28 -

b) The tritium values fluctuate with time, and it is difficult to

establish the cause of this. The fact that there appears to be

no direct correlation with pumping periods (bars in Fig. 10)

suggests that the Cave sandstone aquifer is large in comparison

with the water amounts abstracted. No foreign water (e.g.

intense inflow from the presumably more recent basalt water)

therefore intruded into this aquifer as a consequence of pumping.

This is in good agreement with the constancy of the chemical

composition during pumping operations (Fig. 8). The samples

taken in June. 1970 are generally a bit higher in tritium. a

phenomenon that may perhaps be attributable to the sampling

method. An example would be sampling immediately after start of

the pump. without allowing for thorough flushing of the water

standing in the well. This may result in the addition of signi­

ficant amounts of tritium-rich water from the shallow Kalahari

beds. Variations in the sampling method may. thus. be at least

one cause of the observed fluctuations. This might be true also

for the fluctuations in chemical composition.

Referring to Table 6. we identify these additional features:

a) The two shallow Kalahari beds wells, Steinberg and even more so

the Landing Ground well, show seasonal tritium content variations.

This is seen in the tritium diagrams of the relevant well data

sheets (A-l and A-2). The Landing Ground well seems in certain

seasons to contain mainly the rain of the previous season.

b) In the two Kalahari beds wells a delay of 2 to 3 months is seen

between the rainy season of 1970 and the occurrence of a tritium

peak in the water of the wells. This sheds some light on the rain

infiltration velocities in the Kalahari beds. In addition this

delay rules out the possibility that any run-off water entered the

wells directly from above.

The tritium results indicate unambiguously that the water pumped at

Orapa contains a contribution of recent water, i.e. of the last decade

or two. However, it ia not possible to decide whether this recent water

component is indigenous to the Cave sandstone water or has a component of

Kalahari beds and basalt waters. pumped along with the Cave sandstone water.

- 29 -

It is with regard to thiB point that the carbon-14 data are helpful

indeed. Five water samples from Orapa have been analysed for carbon-l4

and tritium simultaneously, as well as a further 5 samples from boreholes

on a S.E. traverse from Orapa to Serowe. The results are given in Table 7.

Table 7

Carbon-14 and Tritium Data from Combined Sampling

Well Sampling Tritium Carbon-14

Description Date T.U. pmc , ;.---

2175 Oct.1971 9.3 ± 0.5

2182 " 0.4 ± 0.2 15.0 ± 0.4

2198 " 1.8 ± 0.4 12.9 ± 0.5

2199 " 0.7 ± 0.3 9.1 ± 0.5

2206 " 0.8 ± 0.2 20.2 ± 0.8

Steinberg's " 2.8 ± 0.3 86.2 ± 2.0

Mahata " 3.6 ± 0.5 69.1 ± 1.3

Makoba " 78.0 ± 1.4

Tshepe " 1.9 ± 0.4 78.4 ± 1.3

Mashoro " 1.3 ± 0.3 20.6 ± 0.8

Bosupswe " 4.5 ± 0.3

Steinberg's borehole, drilled into the Kalahari beds, contains 86 pmc

carbon-14, which indicates these waters are recent. The time resolution

of the carbon-14 method sets a limit of no more than a few hundred years

on the age, but the tritium concentration in October 1971, as well as

earlier values, restricts this limit to the last two decades. Unquestion­

ably. this shallow water contains carbon-14 in the concentration expected

for recent water.

The carbon-l4 in the Steinberg borehole sheds light also on the origin

of the HC0 3 in the water. As it is found to be tagged with the proper

atmospheric carbon-l4 concentration it cannot come from rock decomposition

but must be of biogenic

vicinity of the well is

humid areas.

origin. This indicates that the soil in the

active biologically as found elsewhere in more

- 30 -

Further radiocarbon .evidence of active infiltration into the

superficial deposits is given by the concentrations found in the

Hahata, Hakoba and Tshepe boreholes (Table 7 and Fig. 11). The

basalt - Cave sandston.e contact in this area lS up to 200 m deep

and these production boreholes stop in the basalt. The radiocarbon

values observed here, somewhat lower than for Steinberg's borehole,

ar.e due most probably to the mixing of recent recharge in the Kalahari

beds with older water.

The carbon-l I, content in the Orapa pumped Haters is significantly

lower than in the Kalahari beds ';\7ater. In order to assess the

meaning of these figures it is advisable first to correct by deduction

from them the amount of carbon-ll, that was brought in along with the

tritium in the additions of recent "ater. If the 0.4 - 1.8 T.U. tritium

(2.omponent came in 'tvith post-bomb raimvater, the accompanying carbon-14

component would have a value of at least 2 - 10 pmc. If this recent

water component ho\\rever "vas actually stored in the ground for a decade

or two, the original tritium value would have been higher by a factor

of 2 or more and accordingly, the accompanying carbon-l4 compound would

have correspond ingly been up by a f ac tor of 2, i. e. 4 - 20 pmc. Hence

all the carbon-14 values observed in the pumped Orapa water can be ex­

plained as the result of the introduction of a small fraction of recent

water.

The interpretation of the simultaneous tritium and carbon-14 data is

therefor.e, that the pumping at Orapa is mainly from Cave sandstone "ith

a few percent contribution pumped from the Kalahari beds, or "ith recent

'''ater from decomposed zones in the basal t. This argument "ould require

that the Cave sandstone be devoid of tritium and contain very little or

no carbon-14.

Another interpr.etation could be that both the tritium and carbon-14

are indigenous constituents of the Cave sandstone ,,,ater. This is ruled

out because if tritium containing water has constantly been added to

the Cave sandstone water, then the long-lived carbon-14 would have

accumulated to much higher values and its concentration would not be

closely equivalent to what is expected to accompany the observable

tritium.

- 31 -

A third interpretation can be arrived at when the radiocarbon con­

centrations found in a sampling traverse (section A-A in Fig. 11 (b»

from Orapa to Serowe are compared with the absolute piezometric lev.els

observed in boreholes along this traverse (Fig. ll(a». ABsuming that

the boreholes are representative of a single hydrological system and

that the piezometric surface is therefore continuous, we could have

a priori evidence of flow from the Gugae area N-W towards Orapa. On

the same ~~£g~~ions the carbon-14 results (excluding Gugae from which

no sample was taken) would support the flOl' hypothesis. The flow rate

under this hydraulic gradient 1n the Cave sandstone aquifer would be

about 4.5 metres per year, ~nd_,,~s_~m.il1'£ the Makoba-Gugae area to be the

major intake zone would make the Orapa sandstone water about 15,000

years old, in accord \;ith the first interpretation.

However, we cannot find sufficient foundation for the regional flow

hypothesis. When we examine the piezometric profile in Fig.ll(b) we

notice that over a distance of about 150 Km it follows closely the

surface topography of the area, whilst it bears little relation to the

\." depth of the basalt - Cave sandstone contact, which is most likely to >:

/~ be discontinuous due to faulting, intrusions, etc~ The levels seem,

to the contrary, to be controlled by the superficial hydrology on a

local basis, by phreatic heads, which find their balance between recharge

and evapotranspiration. This is exactly the model we are proposing for

the groundwater hydrology of the Orapa area. The higher carbon-14

concentrations found in the Mahata-Makoba-Tshepe wells are more likely

to be determined by the considerable Kalahari beds thickness to be found

in the area, and reflect the active recharge to the Kalahari beds, as

discussed previously. The HC0 3 dominant chemistry confirms this point.

The outcome of these routine measurements and their interpretation 1S

therefore that

a) Kalahari beds and/or basalt water constitute a few percent of the

dominantly Cave sandstone water pumped at Orapa and

b) The Cave sandstone water must be of a great effective age, of the

order of at least 15,000 years, or even higher.

- 32 -

The rest level data and the other hydralagical observatians led in

our earlier ratianale to the definite canclusian that the Cave sandstane

aquifer is dynami.c in the sense .of respanding to surface recharge. The

chemical data is in gaad agreement with this canclusian, and the tritium

data daes nat cantradict it.

The carban-14 data are indicative .of the near-static canditians and

large capacity of the Cave sandstane aquifer - canclusians which are

supparted by hydrological .observatians. The disagreement between these

data and thase immediately preceding is .only apparent; under natural

equilibrium canditians the valume displacement fram the .overlying yaunger

waters will be small. Only an sustained explaitatian "ill such dis-

placement become important.

If the carban-14 approach is ta be taken ta a mare quantitative

canclusian, unmixed samples fram the Cave sandstane aquifer itself shauld

be taken.

Stable hydrogen and aXY$en isatopes

Hydragen has a stable isatope, called deuterium eH .or Dj. Oxygen

in additian to the common 16

0 isatape. has 170 and 180 isatopes. On

the evaporation .of water, the lighter isatapes preferentially enter the

vapour phase, whilst the heavier isotapes are concentrated in the

remaining water, The cancentration of 180 is therefare useful in

hydrological studies. together with a knowledge .of the deuterium cont.ent.

The contents are expressed as permille (~bO) deviations from an inter­

national oceanic standard.

In Fig. 12 five stable isotope analyses of Orapa waters are seen to

cluster around the isotopically light corner of the diagram. These

values fall an the lighter end of the Southern African rain line. The

river samples are isotopically heavier and plot on a straight line, as a

result of differing degrees of evaporation of the relevant water bodies.

The few samples from lakes and pans plot also along an evaporation line

and are characterised by a significantlY heavier isotopic composition.

Thus, the rivers, lakes and pans north of Orapa can by no means be a

significant recharge source of the Orapa ground-waters.

l

- 33 -

The stable isotope data (Fig. 12) show clearly that the Orapa ground

waters, shallow as well as deep, originate from rain water that infiltra­

ted directly into the ground without passing any delaying stage such as

surface storage in rivers, lakes or pans "here evaporation, and there­

fore enrichment of the heavy isotopes would take place. The isotopic

"lightness" of the "ater indicates further that heavier rainy periods,

"hich tend to give lighter isotopic ratios, are favoured for recharge.

\

- 34 -

RAIN RECHARGE AT ORAPA

Scant rainfall data for Orapa are available, and only then for

the last few years. The little information that is available is

given in Table S.

Table 8: Rainfall at Orapa

r-i Season 11/68-11/69 11/69-11/70 11/70-8/71 8/71-5/72

i Rai.n, rran 542 250 334 530

The 1966/1967 season is reported to have been distinguished by

exceptionally heavy rains, but no figure is available for Orapa. On

the "Mean Annual and Seasonal Variability of Rainfall" map of Botswana.

1971, Orapa is intercepted by the 450 mm mean annual rainfall line.

This is in good agreement ,,,ith the data in Table 8. The rain in the

area varies substantially from one year to another. Dry years with

250 mm alternate with rainy years of 550 mm and more. A large pro­

portion of the rain comes down in heavy falls in a small number of days

each year. This type of rain distribution will favour ground water

recharge, the days of heavy rains in rainy seasons being very much more

efficient. This is borne out by the stsble isotope composition of the

ground waters.

Orapa residents report that rain as a rule infiltrates rapidly into

the ground. Rain water is not seen to stand on the surface for more

than a couple of hours, even after intensive rainfall.

Several factors seem to facilitate rain infiltration at Orapa, as

well as in other Kalahari regions:

a) The Kalahari sand itself is highly permeable due to the limited

silt and loam content. In addition, infiltration is much

enhanced by the gardening effect which is induced by the

burrowing activity of rodents and root digging animals, described

in an earlier section of this report.

\

- 35 -

b) The crete, below the sand cover, is 8Ktensively fractured and

lets water through easily. This is directly observed in crete

quarries.

c) The basalt is dissected by a large number of joints, some of

which have surface expressions in the form of lines of dense

vegetation. These joints must be open and filled with soil

so that plant growth is enhanced. It seems that such joints,

probably widened by dissolution, can transmit rain water

efficiently.

d) The indurated zone that confines the Cave sandstone aquifer

seems to be partially open to the basalt aquifer. This above

conclusion was reached when discussing the semi-artesian sand­

stone aquifer. Similarly, A. Gibb and Partners reached the

conclusion that "leaky artesian conditions" exist between the

Cave sandstone and the basalt. This they deduced from tbe

interpretation of pumping test results.

So far we have discussed the factors that are likely to make recharge

feasible. The following are observational indications that recharge

really takes place:

a) Tritium measurements revealed water of the last decade to be a

major component in the Kalahari beds water and a small but

measurable component of the water pumped from the Orapa wells.

b) Carbon-14 concentrations in the Kalahari water are as high as the

values observed in recent groundwater prior to the bomb tests,

indicating that these are very young waters. The carbon-14

values in the Cave sandstone are lower but significant, and can

be explained as a mixture of old water with additions of recent

water.

c) Ground water is found in the Kalahari beds in shallow depths of

7-12 m from the surface. The Orapa landscape is so flat,

however, that no underground flow from distant places can be the

cause of water replenishment in the Kalahari beds.

rain recharge must take place efficiently.

Hence, direc t

- 36 -

d) The regional piezometric levels tend to follow the topography

rather than the depth to the basalt-Cave sandstone contact.

These levels are interpreted as being controlled by the

superficial hydrology in the Kalahari beds, "hich through

channels in tbe basalt are open to the partly-confined Cave

sandstone.

e) The piezometric "ater table of the Cave sandstone rose in the

last three years at Orapa by 3.5 m. This has been interpreted

as response to a rainy year (or sequence of years), probably

including the rainy 1967 season.

f) Frequent salinity fluctuations observed, for example, in the

Landing Ground "ell indicate seasonal recharge of fresh "ater,

"hich can only be rain "ater.

The importance of direct rain recharge cannot be overemphasized in a

consideration of the Orapa "ater requirements. If, for example, 10% of

the rain is recharged, i.e. about 45 mm per year, then an area of a radius

of 5Km around Orapa must get rain recharge equal to t~e highest estimated

,.ater requirements of Orapa in the future, i.e. 8800 mS Id. If only 5% of

the rain penetrates, an area of a radius of 7 Km around Orapa "ill get the

required recharge. The aim of this simple arithmetical exercise is to

show that even a small fraction of recharged rain may supply the Orapa

needs of "ater, and that it is most likely that recharge "ill not be the

limiting factor for ground-"ater

needed. This problem, in turn,

exploitation, but

is closely linked

the number of "ells

to a possible reduction

of the effective Orapa plant requirements, to be discussed in the follo,,­

ing chapter.

A final point should be mentioned. Sustained exploitation ",ill

lOHer the Hater table in the Kalahari beds and basalts. This in turn

"ill enhance recharge by diminishing losses due to evapotranspiration.

- 37 -

POSSIBLE WATER RECLAMATION AT THE PLANT

The present water consumption at Orapa is about 400 m3/d for domestic

use and about 4000 m3/d for the plant. t """- . ;J .

A small portion of the plant water is dumped along with the coarse tailings

and the major part eventually ends up in the ttvo slimes dams. Each of

these dams measures 200 x 300 m and about 60% of their surface is usually

flooded. Hence, evaporation takes place from an area of:

2 x 200 x 300 x 0.6 = 72,000 m2

An upper limit for evaporation may be calculated by assuming the dams

evaporate as efficiently as an open water body. Hence, the evaporation

loss can be, at most, 2m per year, or:

72,000 x 2 = 400 m3/d 360

Thi.s figure indicates that the evaporation losses from the slimes dams

are at most 10% of the waste water which is about 4000 m3/d at present.

The remaining 90% must, therefore, ultimately infiltrate into the ground.

The groundwater studies at Orapa are directed towards considerations

of an alternative supply to meet the mine's demands in the caSe of any

failure of the supply to or from the Mopipi Dam. It would seem that the

supply from ground water of 8800 m3/d has serious implications, however,

as it might involve the construction of new wells so as to quadruple the

potential productivity from the three well fields. If. hotvever, the

water consumption could be cut down to about 20% of the present consumption,

or of the future projections, the groundwater resource would be relevant

indeed. The potential of the present well fields is around 2100 m3/d and

could, therefore, be sufficient even for the predicted peak activity for

Orapa, provided the reduction in water consumption is feasible.

reason possible ways of water recovery are now considered here.

For this

The Orapa waste water is, fortunately, clean, as no chemicals are added

in the processing, a feature that should facilitate water recovery. Two

ways seem feasible.

a) Subdividing the slimes dams into smaller compartments, into which the

tailings are directed alternately. The resulting greater head

of water will facilitate the settling of sediment from which the

pure water phase may be repumped to the plant water reservoir. The

'?

\

~ 38 -

smaller exposed area at any time will have the added benefit

of cutting down evaporation losses.

b) Locating boreholes near the slimes dams and abstracting the

water that infiltrates into the ground. It is estimated that

by these, or similar, techniques the water losses from the

plant may be reduced to 10% or even less of the water needed

in the current mode of operation.

The possible reduction of the Orapa plant water demands is of further

interest in that

a) The water consumption may be reduced to a scale that could be

totally met by ground water exploitation with no large effort.

b) It will reduce the danger of the mine eventually having to

contend with the large amounts of ground water recharged from

the present slimes dams.

c) Artificial recharge of the Orapa wells by surplus Mopipi water as

a means of building up an evaporation-free water reserve, was

once seriously considered. Such recharge is in fact already

now being done at the slimes dams and it could well be studied

there. The difference in isotopic composition of the Mopipi

supply and the Orapa ground waters make an environmental isotope

study of a Mopipi recharge scheme eminently suitable.

\

- 39 -

RECOMMENDATIONS

Well siting recommendations

Arising from the present study it seems that groundwater exploitation

at Orapa may be increased by additional wells and development of present

wells, to many times the potential of the existing wells.

In the light of the Orapa groundwater studies the following

recommendations have been formulated regarding possible future well

siting and further development of the existing wells.

a) Wells should be sited on prominent linear features of the kind

marked out by denser vegetation which, as explained earlier, are

due to projections of open joints in the underlying basalt.

Preferably, intersections of two or more such lines should be

chosen.

b) Dykes seem to be good sites for wells. Their presence may be

located with the aid of air photographs, existing knowledge from

prospecting pits, and geophysical surveys.

c) Topographic undulations, even if small should be carefully studied.

d)

e)

A well might be more successful if drilled at the base of a local,

even shallow and small drainage basin, in the hope that recharge

is locally intensified. Excluded from this are active pans which

are likely to produce saline water.

Fossil river beds might be advantageous due to possibly enhanced

beds is likely to local rain recharge.

be even better.

Wells should be placed

of wells 2199 and 2206

A junction of two river

on faults whenever possible. The success

might, at least partly, be due to the fault

on the sides of which they are located. Faults are often

accompanied by a fractured zone along which water movement is

facilitated, a feature that may result in high yields in well-placed

wells.

- 40 -

fl It would seem advisable that boreholes be placed in areas in

which the basalt section is of minimal thickness. In Fig. 13

the safe yield of the various Orapa wells is plotted as a function

of the depth of the basalt-Cave sandstone contact. A negative

correlation is observed, i.e. the safe yield is higher the

shallower this contact is, or in other words, the shorter the

basalt section is. The correlation is in fact probably better

than seen in Fig. 13, as other factors play a role as well. This

observation might be well understood in the light of the

hydrological cycle" The rainwater has to pass the basalt on its

way into the Cave sandstone aquifer. Hence, the basalt acts as

a resistance to the \.;ater movement and recharging rain water

will flow preferentially in directions of least resistance. The

Cave sandstone will therefore be better recharged in localities

of least basalt thickness, which may be located from existing

borehole information and by geophysical studies.

g) It is strongly recommended that boreholes penetrate into the major

part of the Cave sandstone and not just to the top of this

aquifer. This recommendation is based on the small, yet

significant positive correlation seen in Fig. 3, in which the safe

yield has been plotted against the depth of borehole penetration

into the Cave sandstone.

With so many recommendations for well siting, a thorough study should be

made in each case. The different possibilities have then to be weighed up

in an effort to find optimal well sites. These should combine a maximum

of advantages. For example: a prominent dense vegetation line crossing

a fossil river bed, above a zone of reduced thickness of the basalt. Or,

as a second example: if a significant fault is known in the area, one may

decide on a well site along it, at a place where it intersects a broad

vegetation line or, preferably, a second fault. Wells might be placed on

the fault itself, or near it but on the up-thrown block, if known, so that

the basalt section will be minimal.

- 41 -

Well Development Recommendations

The development of the wells, either existing or newly drilled, should

be carried out with great care in order to obtain maximum pumping yields,

and to ensure the long life of the wells. Serious research is warranted

on this subject at Drapa. An outline for some appropriate well

development techniques may be given:

a) Choice of the best drilling procedure causing minimal clogging of

pores and fissures in the aquifers.

b) Use of acid, dry ice. pressure pumping, shot firing and similar

techniques of well development. A. Gibb and Partners mention in

their report one case in which shot firing was applied on well

2183 resulting in a 16% increase in yield.

c) Careful selection of proper pump types and methods of well

installation.

Further Research Recommendations

Processing of the data collected so far at Orapa revealed the vital

importance of systematic sample collection for isotopic and chemical

analysis as well as of rest level and abstraction measurements. It is

strongly recommended that the tri-monthly sampling programme at Drapa be

maintained, and that it should include at least 3-4 wells in each field

as well as the Landing Ground and Steinberg's wells.

In addition sampling of pure Cave sandstone and pure basalt water in

specially equipped wells is strongly recommended, at least as a once-only

operation.

Along with the continued groundwater observation it is recommended that

rain water is systematically monitored at Drapa. Monthly, or yearly,

samples of rain water should be sent for tritium and stable hydrogen and

oxygen analysis.

- 42 -

REFERENCES

Boocoek, C. and Van Straten, O.J. (1961): A note on the development of

potable water supplies at depth in the Central Kalahari.

Rec. Geol. Surv. Bech. Prot. 1957/58 pp. 11-14.

Boocock, C. and Van Straten, O.J. (1962): Notes on the geology and

hydrology of the central Kalahari Region, Bechuanaland Protectorate.

Trans. Ge01. Soc. S. Africa 65 (1). pp. 125-171.

Debenham, F. (1948): Report on the resourceS of Bechuana1and, Nyasaland,

N. Rhodesia, Tanganyika, Uganda and Kenya.

Colonial Research Publication No. 2, London, pp. 31-39.

Dixey, F. (1956): Water supply problems in arid regions in the British

colonies and Southern Africa. Colonial Geol. Min. Resour. 6 No. 3

pp. 307-325.

Frommurze, H.F. (1953): Hydrological research in arid and semi-arid

areas in the Union of South Africa and Angola. Arid Zone Progr.-l,

Rev. Res. Arid Zone Hydrology (UNESCO, Paris) pp. 58-77.

Munnich, K.O. and Roether, W. (1967): Transfer of bomb 14C and tritium

from the atmosphere to the ocean. Internal mixing of the ocean on

the basis of tritium and 14C profiles. Radioactive Dating and

Methods of Low-level Counting, (Proe. Symp. Monaco, 1967), I.A.E.A.,

Vienna.

Passarge. S. (1906): Wasserwirtschaftliche Probleme in der Kalarhari.

Globus Ill. Z. Lander und Volkerkunde. N.190 pp 299-302.

Poldervaart. A. (1951): Note on the extension of the Karroo system in

the north eastern Bechuana1and Protectorate.

S. Africa. Vol. Ill, pp.73-80.

Trans. Geol. Soc.

Van Straten, O.J. (1961): A note on the chemical composition of some

ground waters from the Bechuanaland Protectorate.

Bech. 1957/58, pp. 24-35.

Rec. Geol. Surv.

Figure 2

Figure 3

Figure 4

Figure 5

FIGURE CAPTIONS

Map of the Oraps well fields. Note boreholes in fields 2 and 3 are in or near the Letlhakane dry river bed. Diamond drilled holes are designated (D). Observation boreholes are indicated by their distance in feet from the pumping well (/1000).

The log of borehole 2153 which is representative of the stratigraphic column relevant to ground water studies at Orapa.

The tested yields of boreholes in the three well fields as a function of the depth of Cave sandstone penetrated. The observed positive correlation might in fact be better as it can be masked by other superimposed factors. The Cave sandstone therefore appears to contain water in all or most of its section.

A schematic representation of the proposed ground water regime at Orapa. A shallow phreatic water table exists in most of the Kalahari beds. Joints, weathered zones in the basalt and faults serve as conduits which cross the confining zone into the Cave sandstone. Generally the confining zone is impermeable, placing the water in the Cave sandstone under hydrostatic pressure. The pressure is caused by the head of phreatic water in the Kalahari beds, through the occasional joints and faults. When a borehole penetrates the confining zone into the Cave sand­stone, the water will rise to the piezometric level, which is the Kalahari beds phreatic water table.

Fluctuations in the Kalahari beds water table due to varia­tions in rain intensity will be reflected in the variations in the piezometric level of the Cave sandstone aquifer.

That the model might be valid regionallY is seen in Figure ll(a) which shows the close correspondence of the piezo­metric level with topographic elevation over large distances.

Chemical composition diagrams. The cations are each plotted as a function of the total salt content (in meq/l). Waters in the Cave sandstone are presented by dots, waters in the basalt by x and waters in the Kalahari beds by the two open symbols (0 and ~), representing average composition of the Steinberg borehole and average of the three fresh waters samples taken from the Landing Ground well. The Na, Ca and Mg diagrams show a mixing, or dilution, pattern. The Cave sandstone water composition may readily be explained as a mixture of Kalahari beds water with small amounts of basalt water, intermixed while descending into the Cave sandstone.

Figure 6

Figure 7

Figure 8

Figure 9

Figure la

Compositional diagram of the anions. Symbols as in Figure 5. The compositional similarity of the Cave sandstone water to the Kalahari b·,ds "'ater is clearly shown, the former possibly possessing slight basalt water additions.

Chlorine content in water from each of the three well fields, as a function of sampling date and pumping periods. The results scatter at random in a well defined range and show no change with time or pumping activity. It therefore appears that no significant amounts of foreign water in­truded into the Cave sandstone due to the pumping, e.g. the highly saline water from the Ecca shales below or the saline basalt type water from above. This supports the conclusion that the Cave sandstone aquifer is homogeneous and large compared with the amounts of water abstracted.

Average chemical composition diagrams for the Cave sandstone waters in each of the three well fields. The data used are all. the samples of pumped water and samples from relevant depth profiles (The individual averages for each I<ell are given in the chemical tables in the data sheets in the Appendix).

Tritium concentrations in South African rains; average annual values. Line (a) represents the actual tritium concentra­tions and line (b) represents the tritium concentrates remain­ing in these undiluted waters at present, corrected for radio­active decay.

Tritium concentrations in the more frequently sampled Orapa boreholes. The variations observed do not correlate I<ith the main pumping periods, I<hich are indicated by bars below each of the wel1 field groups. (cf. Chlorinity variations) . The fluctuations are more likely to be determined by sampling technique.

Maximum tritium concentration from pre-bomb rain is shown on the left by dotted lines and arrow heads. Recent I<ater contributions are therefore seen in the pumped water at Orapa.

Figure 11 Figure 11(a) shol<s the approximate topography for a traverse A-A from Orapa to Serol<e (Fig.ll(b». Also shown are an interpolated piezometric profile as well as an interpolated carbon-14 profile, based on measurements from a number of boreholes along the traverse, along I<ith the individual carbon-14 concentrations.

A f10l< pattern from Gugae-Makoba tOl<ards Orapa might be in­dicated. However, as argued in the carbon-14 section of the report, we are of the opinion that

(i) The piezometric profile follows the topography so closely that connection I<ith local phreatic conditions, rather than regional movement, is the controlling factor (see model, Fig.4), and

Figure 12

Figure 13

(ii) The high carbon-14 concentrations at Mahata/Makobal Tshepe are controlled by the large Kalahari beds thicknesses in the area.

Stable isotope concentrations. The letters represent average annual composition for different years for Dar es Salaam (D), Entebe (E), D.F.Malan Airport (M), Pretoria (P), Salisbury (S), and Hindhoek (H). * The rain data are seen to plot along a line, typical for rains elsewhere. The data for the open water bodies, i.e. rivers (X) and lakes or pans (A) lie on different lines representing evaporation processes. The Orapa Cave sandstone waters (.) are isotopically very light, indicating direct recharge from isotopically light rains. This rules out any possible recharge from the rivers, lakes and pans situated north of Orapa.

Thickness of the basalt column penetrated by the Orapa boreholes and their tested yields. A negative correlation is seen, i.e. higher yields for shorter basalt sections. This is in agreement with the hydrological portrait deduced for Orapa (Figure 4) in which the basalt serves only as an intermediate reservoir ,,,ith internal resistance. Hence, shorter basalt sections result in higher yields. The actual correlation might be even better if other superimposed factors are taken into account. It is therefore, recommended to locate new boreholes in areas of minimal basalt thickness.

* (From: I.A.E.A. Environmental Isotope Data, Nos. 1, 2 and 3)

"Steinberg bon-hole

o ....

Air

Pao

5

1 Well field 1

2152(01. 215f#~ 2I3O(D}oo t .219~1 2t18{!l*2f5302175 -

204810r 21',U,oo ,,206810)

ORAPA "2192(0)

;Mlo!9!!.:-­{Diar:nond I \ Pipe- I ,--_ ....

Township -}._+::'7"

Township_ 6WiP«-, 10 k<iWn~jP ...

'~.'~--

'9 km

FIG

---

" ',\ '~~ ~,

'~>::::::'::'::::::" South Rhodesia

~ ~

, , " , ,

", " 'I

,~J

" : ' " " " ;,

:/ " " " ;,

~::;.."

" " " " ", " " " " ',\ " " "~~,

West

Africa

\ '... --, .,,", "":-:;:--~~ field ;$.;-0

'~'21~~~Wo

I~ . Grape

Botswano

Gaboro2t>

Republic of

South Africa

2185a21 -~:::::8'21150

2183{1OOO63"> -"~!1f!~82ll~ 21 2 '0-'""98',' __ _ 83/150 ~-- " ' ____ :~"

21 "!';;e4/150 '- '- \\ / , , ,

2184h600 '- '{~, __ ', :t (,:J ',.

71/_"~~ __ ", ell flcid g C'''Ofl~ O;' ... :~. ~ w , J-,~~ .. , 99

/'"Iv{>r~ '- 25 &'01

;:s" 6"\2_2.05 -Ir. 0,,_

S,,,"·!· "q- '~-:,:.~, ' i;:t4

\ )\ , , I" q ~\ ~,

'\" 1,,\

" \" ~,\ \\ \

'\'\ '" ... :: ':\; i~~:.

tp Let'lhQKtn;.~ ~c~ , ,

o 3

)

+ + +

+ + + + +

+ + +

+ + .+

+ + + +

+ + . + +

+ + 11 11 3 • •• 0 · " • •• • •• • •• • • • •

• • • • , .. . ,~ := • • • •

16 164

• • • • • • • • • • • • • • • · '. , 204 - ---- -- -- - -- -- - -- -- - -, - -• • • 24

25 11-L' .~.!... - - -- -- - -- -- - -- -- - -- -- --- -

" SOIl. grav@!. crete

Basalt

weathered near surface

.vesicular in parts

· •• durated sandstone with thin basalt lavers

Scndstone fine grain.d aeoHum pink

~. Sandstone£=OCII'5e Qrcille9>

Scrdstone fine graine d

Shale and Marl

Sandstone, fine grcined -------Shale, dlark.

21 32

,--- --.~ • .--,.:; --S<J"ldstone:T.tdsDatiC )

FIG 2

Kalahari bedS - - - unconformity- --

Drak<2llsberg Lava

Stage

Stormberg

Karroo

Cave sandstone Series

Stage

System

Red beds Stage(?)

Ecca

Undifferentiated Series

r---------------------------------~O x - ~

-~ N

x

0 x x x -

~ ID ~

X "0 --M

X XX E

- ~ -0 - "ii XX >-

X X

X - ~ X

- 0 ~

~I~----~~.----~I-------L-I----~I--~O ~ g g g ~

l 'F + ,

<l> ..Q o

+-'

+

+

\ \ +

+

+

+

+

+-' o (/) o

.D

+

+

+

+

+

+

+

+ ..

+

+

+

+ +

+

+

+

+

+

<l> c o N

U 2 o L ::J U .c

•

• •

• • • • • • • • •

• .. • •

• • • • , •

• • • •

• • • •

• • • • • • • • • • • •

• • • • • • •

• • • •

• • • • • •

• • • • • • •

• • • •

" - " -8 " ># '" " '"

~ " )~

-~ "

.::::: " 0-

q,

E " " , ,

"l< 8 12

" " : - .!2 '" ~ ;.

" -." ~~: . •

'<ll" ''1 ,.p .. .. till," ;' ." ~"'a . • . 't'l f ."", i ,11 0 , .

, Cl Cl Cl '" "" - Cl ...

Cl c:, 11 baw DJ 11baw >f

Cl

" " ~ ,..., " '" " ,,"" ~

8 s:. "" tf q,

" " E

" " :§

'" " 8 t2

- " " " ~ .~. >< -"~~i

'. ~: ':, .it J •• " , .

• . . ' ,

8 Cl Cl Cl lI) "" --

11 baw oN /1 baw 50/

I a

'< -l " ~ '< " '< ~ '< "

'< '< '< '< "

~ -- "-tr-<IJ

'<

I '< Eo:

:§ " " '< '< '< ~ ~

;!2 .'< " .'s.o , " " '. ,,:.;. , .

f '" '''V1it • • 4 . . .. ! : . ~ 0°; .<1

'V .0 . '. f

..l , I

~ a a "" - a - a 0

/1 baw 70S /1 b<iW .::I

'< a - '< a

I» " ~ ,,~ '<

'< '<

's.o '< '<

a -- a "" "-

tr-<IJ

" Eo: '<

0 -'< '< ,Q ~ ~. '" ~ ~ '0>':' •• ': '< '< ,

" , .: •••• 'f~"'; '< . .. " .. -:- .: ~ .:. :.).:; 40"0:: . "? .0.· ' .

• f

I I I

1§ a a a a a a a S? a "" <0 '" "" "" -I/baw 1J I/baw COJH

<Den oen N_ NN o.

0

o •

"

I I

8 8 <Xl (Cl

(Y)

:g

i1:

•

0

o •

• 0

• 0

o.

-• .' -

o.

'. oAt 0

I I o o N

o I

o o <Xl

N

"0 Qi u::

• ....

0 •

.. • • \ . •

••• ••

• •• • • • ..

,. •

•• •

• • -• • • •

I I

8 (Cl

/lBw I.:)

-"0 Qi u:

•

. .. • •

• ~

a •

'¥

.. "

- .....

. .. • ..

• ,

• I I I

8 N

8 ex>

8 (Cl

o

•

•

•

•

I o o ~

•

•

I

8 N

-

--i

-

-

---

(Cl

N

N

N ,... en

(Cl ,...

N

N

(Cl

~

N

<Xl

(Cl

~

N

~

Si?

<Xl

(Cl

en

o ,... en

en <D en

ex> (Cl

en

o

-....... 01 E

'1000

100

10

FIG 8

Field no. _2

, ...-:::: 1 , ----- 3 '\ ...... - ..

1~----~------~----~~----~------~----~ K No Mg Ca F Cl

FIG 9

T.U.

60

40

20

1970 1965 1960 1955

T.U 2

1

o 2

1

o 2

1

o 2

-

11-

0

2 I-

1 I- 1

o 2

1 -

1-- -I> ...

1---[:>

r---C>

~--C>

<E-

---[>

L ,

- -[> r--- I T

o 2 -r------~ 1

o

2

1

o o 2

1

o 2

1

o

I-

I-

I-

~

1---[>

---f>

- --[> t

I ,

FIG 10

2144

+---t r--. ..1 I , I

2174 ,

h. ... , ..,. '~ r--...... .1 ~

2175

+ ....I..

T , 1 I'--- 1

2179 T

.... ,

I , ,

2182

,~ 1 ~ -[ I

1 , 2183

_I I

~ I I -4

~184 .J,.

i- -----I--l 1 I

~ T

I ,/ ,

I , •

I 2199

j ., ~ ~ I I

2206 I

1 1. I

, --I--- I 1 I -;

• : 10 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6

1968 1970 1971

~

0 ..J W i:L ..J ..J w :;;

C\I

0 ..J w i:L ..J ..J W :;;

(Y)

0 ..J w i:L ..J ..J W :;;

~

w E

1100

1000

FIG 11 a

Approx. Topogr?phy Section A-A

Ap prox. Piezorn. Levels

Carbon -14 concentrations " --- .. ----

,....- ........ /"'''', I

100

/ ... , / ,,/ _,e..-__ .... --".

.,.. fJ -. Tshepe ,.-' /"Iakoba "

.Steinberg

" / , , / "

I '" , V , ~ \

/1 , 50 / I \

/ ' \ / , \

/ ' \ / I \

/ / \ / / \

/" 111 ," ~Mashoro " . ." ..... /" ." .,' ' ....

I ,.,; " ............ . ... .... ~supswe

o 50 100 150 Km

FIG 11 b

Steinberg Cb \ ~\

; /'_-...lrr?V

A 01--.

11 J Orapa "'-.II!' /

~.Mahata ~\"

Tshepe.~Llgae .

~. lVIashoro ---a "0""''_ \ SCALE

20 40 o 10 50 30

I(ilometres A

~o

1

1 .,

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

yi4!ld m3/h

300

250

200

250

100

50

FIG 13

o

o

xX o

o 'K.l 20 30 40 50 60 70 80 90 100 110 120

d4!pth of

x - Fi4!/d 1

basalt - CaV4! sandston4! contact, meters

o - Field 2 6 - Fi4!/d 3

APPENll]X

Information shee.ts in this appendix 2YC. nUlTl.bered Al _ ..

A2'<3. They contain information on the chemistry of ineJivid-

uaI horeholes and wells at and around Orapa as well as iso­

tope data, borehole log$~ cher;d_cal composition diagt'dms~

rest level diagrams and geE0ra1. remark,s on t"hcii' behaviou.r,

hi.story, etc.

Pl-i steinberds bon:;hofe • .J

Tr:tti= 7.'<:11 TJ::. ~e Dek -!.:'1; m pH G0 3 ::CC

3 Cl 304 F K ~-'a Ga ~:r; 'I'. ')~ "). . "

~~;-c: 2;/:.,1-;0 2.S'~(.3 7/ ;'/70

2£/S/70

21 '2/7C

27/10/70

7.7

7.9

8.2

890 n2 163 l?9 125

137

136

CB 15

8

4

4

3 3

390 2;, 27

25 22

12 :;2 : •• ;:::'c. 4

27 39

025

81e

733 722

10

3&;: • 4 37C

22

17 1204

22('2

1.;~('.3

::-. ~:('. 0

25/2/71

22/4/71

7.2

0.1

8. J

66

87

94

94

55

G

2

1.

3 3

;~(' 5

1.00

325

21

22

21

24

20

1152

}1.91

1::;:;0

2.:?!.C.2 0.7!:.(.?

ilJg/i '"' B25 G 22

J 2/5/71 (~.8:0. 2

'iT ~11

S'teinbe .... g

meqll

::.~/6/71

16/2/71

1;'/10/:-::'

I""'~~:-:,":e 9 s~.r"p::'es

8 .. 1

7.7

7.7

70 C9 60

7~S

7'~9

. 775 7%!-.'.5

:J ... ~,:: :;::'~l't~~ J:l.:?~ co" HG03

01

71 5/70 26/ 6/70

21/ 8/70

27/10/70

"I <),

28/ 2/71

4-171

7.7 7 ~,

8.2

7. '2

8.1.

8 • .)

8.1

7.7

7.7

0.9

1.3 2.2

2 .. 9

1.4

2~ 3

5.0

2.. ,)

1.'h6

1.3 .. 5

1).3

12.C

3.1~

4.6 346 3.5

D.8 3.9

13.5 3.4 12.3 2 .. 5

12.3 3.:> 12.7 3.7

87

124

13Q 128:12

so "

1.8

0.3

0.2

2.0

2.0

1.2

1.1

2 .. 0

I,,}'

54 97

,4 62!.28

" 0.21

D.n 0 9 22.

0 .. 15

0.2.1

0 • .1.5

0.53

0.42

10

8

1,

-S!.z

K

0.10

0.08

0,08

0.10

0.e8

0.08

o~o8

O.C.5

3 2

3 3!.O~4

353

1.16

')7:-;

390:'11

N,

17.0

:t c. 1

16.1

17.6

It.I..

16.7

16.9

18.1

16.:;"

25 21.

21 2Z!.2

c.

1.2

1.1 0.9

0.1

1.1

1. }.

0.3

1.2

1.1

2 !~

21

29 2!.~.2

;'~g

2.2

1.9

1.8

1.7

2. C-

2.3 2.C

1.7 2 .. 1~

1'251 ..

!2?8

J./.'51

1 :'S;·:!:.81,.

Total Tot!>.l .ar:icn:s e ... tio:1_~

20.1

19.1

18.0

18.7

15.2

18.S

17.1 19 .. 7 18.7

20.5

1 ~~ 2

HI.S

19.5

20.5

20.2

20.2

21.1

19.8

Total ions

l,.o.6

38.3 3$,3

38.2

39. ;

" ' .J, • .L

:37.3

1~0. 8

)8.5

22/ G!n 15/ [:/71

l3!lC!i'l A,e!;,;I·r,f!) ;? c.:llll~~e~ 12:. ~!o .. ? 3. 6 t o. 3 1. ;:C", 6

0.21

O~15!.O.1l

0.08

O.OS!O.Ol 17.0!.o.5 1.1!.O.1 2. O!O. 2 18.3~.6 19.9=0.6 38.7!1.2

I le

i 3,' ~

;\ / \ 1910 197~ i j972

i

,s~~ • ..,!:;.. • ..... -..<{

~ i r~ , \

\

;-- -! /t I ., /' . I" /' I., ~ 12 4 8 12 I,

20 r' ,! 1 ,r-"rr',T-r<-r

1000

1

1 "

.,.. { "'<" .. .?:~ ~

I I) •• i ~"'Jl" N.. ;' .. """Il 100 r iJ ~"'"" !/,,:" .. _";~,"" ~ 21-

-E ! ';: 1!.-~ I

If " /' ' ,/ t ')--t

~ • •

22r (': --- -<l.... " T ' .. , .... -~e-' ""O""e/--....~/

1 I} .'"\ / \\~ .1

i" 'i ...... _ rt \. ,:;.,.. I /l ~ If' ·:1

0_1 __ , ____ 1- !

v 2 (.. G -isf-, -',;7;0'-;'12';--2';-,---;1.'--';-6--;0;--;';;;0 2"t E

I 1,~, If \\ J""

101l/ ' Ii 7 ~ 1I t , ~/,'. 1970

Stc ;n:'c:-~' s Scr'2_i.:-2l.£ ~~c~n tc ~UV2 ~~~:! In ('~CC?t for signific~n "r,':ore:1~ Cl i::: 10',: (l~: i.a~Glts, then i~ a ?c r~ I~dly r0c~arge~ by ''':i: (,.'.: .• !:'.:~!<':'-', p0st-~9 ir. ;_c"t~·,; ~h:,t d:c ~:3

I 9 7 j

Ne 1--19 Cc. F Ct SO.. HeO!

is pr-i "tely ol . .-ncd ar,d PoD informz.tion is a\',lila):>1 reg.:l,di'lg it.s Jcpth and gcclogict<l infOTln3ticn. It is n?~r?~ OP for yt3rs. P~mped sa~pl~s have ~ccn t ken fr~m 1970 to J972. Th~ ~atcr is of constant c0~positim

S04V 1l3tlons, ~hlCh arc not ex?]a~n~6 ~t prc3e t. T~ ~~jor dissolved s~lt is NaHC03(786 rng/l liC03) ,r:Zil). The '.,"011 ~;(>,::-:.s to be ~~"llo\" (i1Jg ;nto t\~ Kaiil ari beG;; <l1cne (OY, if slight])' pcnc-::rntir.g the

'!:j"lf:. ti::J.t cor:.t,:ins nn S21ts). The -:.:oter see;;,~, to 1)'~ typ c:J.l Y.:l]~;l:ln_ t-eus ,,':J.tc:-. "Th(' ..... ~ll ap;->c"rs to be nfil~rati~E r in ~ater 2S is indicat~d by the tritiu~ cia :1., ~~icli is ahove the 2 T.U. cc~tcnt typifying 1952 Z, i .c. ;'05,- -J~\O te~t ~, .. ;:;ter ~:l:" l;(~(;t, recharged. 'Tin.! h ~h c:noon-14 \·al\!(). nf SO'!. :.lOO>::r" carbon also e, '.!:; , .. <:or,. ::>; c::'(. The source Co: ti~e nco! i~ cl~:;cus"';:"( ::"!1 t;lC cart-cm-I .. section of t.':'lis report. :l:>.

! -

A-2

:7eJ.l

L~r.;dine

G:-OUrlc.

mg/l

LandinIJ.3fOUrtd Wef[

D~tc Dep'th p "l

7/5/70 26/3/70

26/6/70

2J.hV7C

2':./2/7:.. 22/,./71

12/5/72 16 / 7'71

1';'/7/72 A"" • .3 *l.3~l'les

~?:!:.l a;1<\ri 3Ci.!.3"

.Av. 4 s;::ll':l:,lc:3

"3a~~.ltic"

32r 28 L

J = 2+ ,.. E " ~ ~

::~ :~

:?~

8.2

7.6

8.}

8.2

8.2

8.0

8.2

/\ / \

\

co}

?c

13

52

lO

U

39

33

:-:r":°3

765

812

717 6<;1.

618

614

669

647~19

727:'62

1

/''-

1\ // ". \./ 1

!

L ! 1 1 ! 1 i ! !

°2 {. 6 8 10 12 2 4 6 1970 1971

C:1

7e-7

H37

le-h?

209

307

9 ;)4

:::15

21.Y:1.2

9Bl!:.:?3

W!. ? K ;'i"<:o. Ga :!p;

267 3 5 720 54 G5

313 3 5 930 75 %

230 1 5 365 59 37

122 2 2 400 17 '28

57 4 4 575 22 56

1'~;8 6 5 838 62 71

157 2 4 !.B 2:' 27

122:'23 3:'2 3!.1 396:'l!+ 21~·5 57:13

2£7:'23 3:1 5:0 833:'59 48:15 8 ;::'7

!OC01l ~~. j\ J I /1\\ !~ .. /,j ~1"'~ J .~\ . liS,~\;l"

! r \~..::--~~ ~(.! 'ZJ/;'<""

V. \ ,,-""" r""'

j \~-'" It ,! f \_-- ".,." 'I .0,' ~"~i }'; N)._ ~

V. It , j

l\ Nu V,9 t..:ar ~t SO ... HC0.I

T. T,. 1.

2580

3Ce'"

2:'1.6

126'::':

14.':f;

:<:720

] 4~·2

11:0.3:'90

::::E25:'128

7ritiu!"l T.U.

;;2. S:J.3

13.l.:'r·.E.

2\.3:!;.C~6

1.3./..!:-('.5

:c,. I

I\.:)

..

A-3 Landing Ground WeN (contd)

't'otal ~ot.Ql '1'ot.:l.l '\Tdl Dl;lte Dept::", m pH C0

3 EG0

3 Cl S04 P K N", Cc li'g J;:.nion:l: c.:I.tion.s i"ns

Landing 71 5/70 8.2 0.6 12 .. 5 22.2 5. G O~:i6 0.13 31.3 ?.7 7 .. 1 40.7 40.2 80.9 Gro>l.:')d 261 6/70 7.6 0.4 7.1 32.0 6.5 (:,,16 0,,15 1;0.4 3.8 8.1 502.2 52.4 104.6

21/ 8/70 8.; 1.7 11.,8 2~~ 5 4.S 0.,. 05 O.l) 37. <5 3.0 7.2 46~ 9 47.8 94.7 25/ 2/71 8.:> 1.3 10 .. 7 5.9 2. :$ O.u. 0.05 17 .. '+ 0.5 1.5 19.9 19~ .'J 39~ 7 2el 4/71 8.2 1.4 5.0 3.7 LS 0.21 0.10 16 .. 3 1.1 4.6 21.5 21..1 43.6 16/ 7/71 8.0 3.0 10.1 26.9 5.4 0.15 0.13 56" '+ 3 .. :t 5 .. 8 41.9 45.7 87" 6 meq/{ 16/ 7/71 8.2 11.5 6.1 3.3- 0 0 11 0.10 18.0 2.2 20.9 20 • .3 41 .. 2 Av • .3 aa:tlpl~t;

't?i::..l.ll.h:.>.::-i Bad",," 10.6=0.; 6.8:'1.2 2" 5":0. ~ O.2~O.05 o. ou!.o. 03 17.2't.O.6 1. l't.O. 4' 3 .. 1!.1.:<' 20~8!.O.6 20.1~!.O.5 41.2!.:t.l Av. 4 ea .. ::rples

"na:S"lltic· 11.9=1.0 27 .. 6't.O. 6 5.6:'0.5 o. ~tO. 05 0" 10:'0. 0 3S. 4:2. 6 2.4::'0.8 7.1!.e,. G 4.5.l.;·!.4 .. .3 1.6 .. 5=-3.6 n .. 9!709

The Lnnd:'ng GrOllr!d \\'e:!.l .... ns;;. trihal .,.,·ell that ~ad to be <l.bandoned last year as it was to be included in t::'e nc\~ Orap.: security area. So lntOr:atlon rcgarcling its g~ological profile is availabl~. Sen.'"n sar::p'.C:3 h3\'e been cilc8ically an;;.lysed [rom 1970 to 1971, .,.;hiie the well "·~s pumped. The chlorine cur:.c{;I"J.tration ..... aried re:'":!r;;3t-l), .. Three of the $a~plcs arc ty?ic<!l Kal;lhar:;' beds .... ·ater (rcsc;nbling Steir:oerg's .... ·ell :md s11«1lo·,; "\o,.·ater €TIcol1nte:'cd i~ ~ells 2130 and ~IS9) ~ith loK Cl, 273 mg/l (see Table at tOp of this dat~ sheet). Fo~r of the s~~ples wore of typical bas~lt watCl· co~po~ition, Ki~ll an average of 991 rng/l Cl (Table above). It scc;~,s. t!lcrcfcre. that the Latl<.iing Ground .... ·cl1 :!.!"' ollg in the Knlo..'1.ari beds :,.nd the top of the basalt, it:. 0.

sectiop of the latter. The proximity of a pan might be a ccntTolling influcn,e licnce, when the Kcll is ill

Tain ~ateT the Kalalla~i beds ~atcT type domjnates, but when the water levcl is 1 w it is the bEsalt ~ater tha The tTiti~~ co tents ldiagr3rn/Pa;e A-2) v&ries seasonally 3tld the hiCh~T vnlu~s r:dicate that occasionally ra p1:"evic:.:s rc:ar S oO::lir,;ai;;;;. ·ihe 1970 peak shOl-:ed up 2 - :; ::-:onths a:tcr ti:e Ta oy so.sen. This time delay tion on rain i filtration velocities in the Kalahari beds, and rules out direct ogress of run off water into

salt containing: ] ~i th TcchaT.c;ing

dOr;1ir:&tcs. n "·2te-T of th~ &i~~s so~e informa­the .. ell.

h. o

A-4 '·"Tell

2118

(:'~c~d 1)

mgll

Date D:~

3i5/53 1.29.9 20/5/6<: 8/2/69 129.9

25/3/70

7/5/70 14/')/70

25/6/70

23/6 '70 A·.-ero~e 7 5o.;'ilpl~3

'liell Date

2118 3/5/63

(field 1) 2::/ si 6S

3/2/5$

7/5/70 1!;./~·/70 meq//

j)~pth ,:In pH

7~7

7.5 7.9 e.2

r?

7.7

7.5

7.9

8.2

8a4

7. 2

7.1,

063

0.6

0.7

0.7 2.2'

C03

'3

20

20

66

31:!:.18

RC03

7.0

7.8

::co;

1..26

4'"b.

!,~)6

723

42/3

690 r,;:o:)

565~1) 7

Cl

18 .. 0

18.2

70':> ·17,,8

7.0 16 .. 7

2118 l'ri ti urn

Cl SO.... F i': "Ta Sa l'~ '!'. T). ~. '1'. D.

6)0

£~, 5 ';:~2

;;')4

644

652

6<;2

637:::'1 1,

S04

1.1

3~ 2.

53 l5!

125

103 11.5

115 118

116!.22

p

1 "c.

1 15

2 15

2 10

1 11.

2 10

2 11 1. 5!0. 5 13!2

K

0 .. 1.::.

0" 38

;(a

l? 6

2"1 ~ 7

·<1.3

23.3-

Z1~ 7

4)0 6l

5CO 79

1,90 7'~

5;,3 7('

5eo 7<'3

560 75

550 75

512~32 n!.5

c,

3 .. 0

1 •• 0

3.8 3. :;;

1.7

}9

;'9

51

5.3 45

5] 47!.3

~'[;

3.9 3.2

3.2 I,. ::;

251,0

H'2!,.

1.712

O.c!.C .. 2

Ise!,

lS{,0

1~'34 2.E·:"~.Z

';~.'. 1 ~ .~:('.

1 70)"'" ..,., ,/_-v/

Tot3.1 'I'o'tn) ":'()-:;,.,l ur.icng cati0ne. le:;::

26 .. 2

:-:9 .. 1 29 .. 2

2(,.9

2~~. ;

53.1 Sf.'~ <+

;"7 .. 9

(;2~ 5

59~ 7

25/6/70

2}/8/70

Avera~o 7 ~~~ple~

8.4 7 .. 2

7 .. l~

8.9 18.1

11.3 l8,.!.

11~3 l<!'

9.2!.1.9 17.9!.O.4

Z .. G

Z,. 1

3.0

2.4-

2.5 2 ... :!:..0 .. 5

C.05

0.05

C.02

C.:1

0.05

0.11

O~ll

O. t"'J:'O. 03

0.';;8

0.25

Cd5 c .. 26

0 .. 23

.O.33!.O .. Sl

2~ .. 3 23 .. 9 22.3~1.4

3.9 3.3

3.8 3 .. 7:0.3

l.t..

4.0

1 ... 2

31. 2

2": .. 3

32.2

:; 2. 2

2S.7

31 .. 3

3C~ 4-

}"2.5

)2. :c 3.9:0.3 29 .. 9:'1 .. 730.2:1.6

64.·7 61;. ~.

6C~1:'5.3

OF-~ K.S. ! + I

201 + i 1+ '

l,Jl +

601> + I b. ~, +

~ 801 . E I + I +' ;O() + I , '

LJ 17.01- .••• J C.

L'..:..:-.: s.

1970 ! g 71 ,1972

("> .; 8 12 U I ' , • t. 8 12 t;

VI r-~ r.--r-r t 11i""- ORJ .. •• SI""""~' ~ p~~(J, .. ~-_.o _ J

E IS~ r

o ... ·~ ..... ,,: .. (/

'iOOO'-! " ... ", I ~ ~ ,c,,"

I f'%' J ""., ~r;~~"

I '~> . " \" ',' /,,(L., • I~"+"",. e ,',;1'/' ;!)Vl .. ~~.1'l}" f! "'/

~ r;; '., ,:><,> if ;-; 1 iT '\~?.,... !! \/ C !!t '.~,.- j!j 'It - 11

r' P . '} o f ,!

I, J,' • ij , I f L-~..I-__ ~

K N:l Ma Cc. F Cl SO.: Heo..>'

K<:~] 2:;'1.8: In thi::; ' ... ·cll 0;1.1; C~n'e s<lr.dstcne type v:~ter> >.-:ith Cl > ~G~)3 by 1\'~ ght) ",nd NaCl be:ing tl~e c.omir:atir:g s8.1t. h:.:.s oeen cncol:n::('red, \:,vcrl i;) samples co!lect.~d ,,·it!l a depth. 5<lm?!cr in tn~ <>:>a1 scct on. The Test level rccoYc!"<;-ci after r:ess"tior, of pumpj.ng to ab')ve it.::: or g.1.n.<"l lcve (Table 2, text) in ;il-:,:)'J.: h'cly£! '.",Or:.t:i$ (b)'drcgr;.lph 2.bove). The che!:'lic<:1. co:::po~;i.c.j!);1 ()f th~ rcrc.:;tcd s","'p!.ings j:;. (".01:5 ;~"t., cxccp for so~e SO,. variat.;u;"s.

)::.. I

..;:-,

A-5 2130 T:-i~iur.o.

":·,..,11 v02tc DC9~h, m r:': CO~ F.O:° 3 Cl , 5°4 F K Ra Ca i'g T. ;). S.

~. v.

2130

(n<ld 1) 13/5/68 8.} (1028) ( 1. G:?) (65) ( 7) ( 5) ( 1.-25) tiC) ( 1,7; ( 1,,72)

13/5/68 7.7 30 353 631 152 1 15 500 44 V" 171.0

13/5/68 7.7 487 610 1/.3 1 15 SDC ,8 /V 1?96 mg/i 23/B/70 7.5 942 624 92 4 8 0"15 59 57 2t11 ? C.5:('.3

A-fer-aSe .3 !>!UD.ples 703:283 62,..::'5 131 !z6 2!1 13 :!:3 51.2:56 Si:9 .'.5:8 1 81.';:!:] )1

Tot"l 'total Tot.ll.l

'irell D~te D~pth.:ro. yE C03 l:!CO~ , Cl 3°4

.p 'i~ N. C::>. llg z:;.."lionf!. o::.'tions ~or.s

2130 13/r;/53 8.3 (16 .. 3) (7.4) (1. 4) (0,37) (0.13) (l8.5) (3. 5) (3.9) ( 25. (;-; [2';. c ~ .'CZ' .. C)

(!icld 1) 7.7 1.0 5 .• 3 17.8 3.2 C.C5 0.38 21.7 2.2 3.3 27..3 27.6 Si..9

7.7 B.O !7 .. 1, 3.1 0 .. 05 C.33 21.7 }.,.1, 3.1 28.5 28.7 )7.2

23/8/70 7 .. 5- 1504-. 17.6 1.9 0 .. 21 0 0 21 ?7.2 ;.0 4.7 .3)02 55. 0 70.2 meq/l :\ ... ·,~ra~e 3 3<Uilr1e-s 11. 5-:1 ... 6 17.6:'0.2 2 .. 7~O. 5 O.11!:.O.3 0.33:'0 .. 8 2;. S~2.4 ZJ~'.'o:; ).7;"'.7 30.;'!-302 3C~4:3.0 60.7:'6.2

or"==; K.i3. • • 1

20 ' I i +i

l.cj + ... i

lOOOI

1970 1971 11912

lOol

.L. . !!'0c [\. ..~1t.~. l,' ~ f,~" J~" /; \~ r '.',V;/

~ .0: • E

i' I €Cl ... +1 b.

I .' 8°1' I I .. , "X)~; t- __ "1

I" -') 12CL .. ~J C.s.

;'8124d124 ,8 ~r--;-. i •• , ,. I I

i" j2 $_~O'"'o-o-_~4> <l.> :r-_ o '-'-

~ r ORL ,t

16 r ~--_<!/

I JI \~7"~;:~ I ::;'~AV! i/ji-·---·-1 '

1OY/ it r ill L t ~~ Ne. ;.~ ~ Li -~ •

._.9 C." F K ,

c. so.:

11'e12 ::;30: Xo COCl.!t:cDt.,,'d d-:-pth s2.mples exist for th.i:: \:cll. Y';i:., on -;,)/5/68 two sal'lplcs i<c,e t8k~::: (Tabl~ 2.:; tOp QE th O:\l' bCln:; 101, in Cl, 262 l"'~g./l aad hi)~h in ~~C03 , 10.;CS r.1/:/1; aT,'; t!':c ot;l"~- $<1'"1)1e higher i,l Cl. 63}' rH.;/l <':1;' t!1e ":or:','",..;.t being SaCl. It Sec;r:" , thCl·efo~e. that th,~sc t.'~·0 s'!iT:pl~:; ;./('re to.kc:, 01,:-1·il:"; dTilling, onc being "ty;?ical Kala);:ar"l b{;c\~~ '.,-:1

s-'conc! being f,om tt",~ h;:,salt. il~ a [n,sh water pOY"tio)\ f)t the latter.

page), n:;,: f>:tlt. eT I the

T:-.e chc ... i:::<i.l ~cl::po~iti.op.. cvc':ils sl;lall fluctl:aL.ons {corr.rositior. di:;gl'8T,1 :~;',"v",)_ Th.; ,est It''':cl recovc.y c ntinucd OVCT [ourtee'f, i:,0n::hs .'l.:-tcr p<';!'lping i~ the field was ."toppeJ, but eventually -,:35 l~lgh~·r re:'! lc\"t'l cn~;ounte.'t'.j \-I'h le drilling: ("labh 2. te);t;.

thzn the

HeOJ

h (1

;

A-6 -; c'2 J

')~ ,,!;

(:":el:t 1)

, ...... ·v, If I '::1 /

t·"

meq /[

:;'C.'::~ ;'c" '~ ;:;

13/5/ =ss 1::'5/"S 13/5/,)5

2~;/3/fC

::: 3. 'c; I •. "

27/:,,(": 7e.

2: .. / ,:;171

2 7.l;.17~

:::./,':/Tl

,: .. -,-<;'::'8.:::e 8 s::l.::l?lcs

'Jell Date Depth,m

. 5 .' ~.:

:: 5.-" 3'.' 7e,

:::;,,'8/;, ?7;"~,',-/-C

~. "

:J ',::,

.-:: :':~? 1, ,~.,

0[---1 iC.8

2Cj -t- I !{- • , I

40 1" -t-j

I "I 6C:~' ...! !).

t2 I' i .;: SS! {- : Cl I"l" !

E ""I + i 1'-vl ,.,. i -}- :

120L::.....J !~,~',:I C.s.

?,",

7., 4.

7.3 "7

0.3

s~ 5

7. L.

7,,4

7 0 ,1+

7·5

pP.:

7 D!;.

"7 ~ 3 '02-

?,~ :;

/~ i,

, . '-", 70;'

7.5

se]

66

6

cc]

?~ 2

C.2

EGO,:,

821

706

IOlO

7)e

lCh8

1022:

770

:~ 78

823:176

FE;03

~-j., :"

1:!.~ (;,

1 ~~ 7

ll~ 9 17 ~:

... ')~,) ! .0: 0 <;'

,,1}

Cl

:;LO

:t~<>]

E~ 7

le C

,;:;~ 5

-, ?

1 ('~ 5

:. 6~ 7

2744 Cl

391

hi3

663

250

21.!"

257

371 592

1,05=123

SO}~

c. ; 2~ 1e

'<. 5 C0 6 c-~ 3

J. 0 ;~

- , '. ~ 3

;:C"-

1;.1 ...

J.14

122

29 15

59

15[,.

231

<]6:59

?

C.IS ('~::>::.

Co ~. 5

C~::. S

C'. :::.

('~;:l

c? 7.1

0.0]

~

3 4

6

3

" 4

!.

1

::

9 10

4

5

" 5

12

11, 4:'0. <] S!.;,.4

K

'"' ,,~

C'~ .:: J

Co :;'0

()~::'3

Oo~O

(". J ;:

8. :':;'

C. ;; G

, 425

US

725 175 372,

1.00

3~lc

1,.:"6

t;;?

18

87 1.2

20

6,)

69

85

95

5-3

56

53

5;,.

57 55

55 50

:!.I, 7~. 2836 2152

123 :)

Ins :372

1668

172C

Tri -:::iu~

T. L'.

L 7':'0.3

Cel:'':'.3

:.7:C.3 0~?~C.2

C~~::'Oe2

'.1,7:71 62~l,3 53-::'1.2- 1~5;:'2·:;i.

nil Ca MS

~ . ;; -'. ) " . ..)

::.5 2~ :.

l'.'. ;. 10::' c !~

:'::.1, ~. ~ -' I.. {

':"." ~. 5 '",,5

n.] .< ", ~ , .5

-,', , .:: ,

Total Total To~al anions c~tions ::"0:;-,$

': .. ~.

- ;. ? Y:. :. -, ,-., I '. ~

-:c. s· 2l~ S .3

2 .• .$ 2;,. :,. '-.;-~o

;-:-:. ;. ;,5. 5 " ':

:'. ? ~ ;. ' ". ;

2 C , <; -c "3

~"=;:" <) ;;0 -:: ::.C':'?{ 0.~J:C.C5 O.21~".? r '. 1':;'·:,. S' '.',:-:-.• '; 2"1.3:3.5 27.4:'3.1.. 51 •• 7!.6.9

1 9 7 0 1 S 71 I :972

10 !., (j '2 , ~' ! 4 r L~:-<"-- i :l

17. 4 -.----;----;--;-

~ jl,~

~ ~~r­~

",P 0' C::, ;

0-0 / ~~ , o .... ___ .>::l

.=. :DOCr

1\. ,"'- /<:: ! ... 'k' .:

<;.:0) I \ }~ i If r l . "...,"" '.'

lj/ ~""'~;,~ l

r1t! f' iO.l . :' f

! / ,j ! J

K NO Mg Ca F' Cl

.,

5O.i HCO!

~'~ll ~~~~: a~~/~~t~~~7.~;;i~~:1~ec~~;~;:-:~G?t;1 samples 0X:'S~ for ':::l':"S ;"cll. .:"11 sat:'.!?lc:;. aDalyscd ar.'2- of the Cave 3?nc.Stone type .. lit;" :Do. !:-:e c!":s:-:-.lc.::l sO:T.;:;osi~ion i.s cOr!s~<!r:t except for one ex~.!.'e~ely :;'0;', SO,. '1al'Je (co:n.?ositjO,l 6i2<:jrc::r.). :\E:S:;' l~'J~l -r;;:c~·./~~·y is se,,,n to ;--:2ve ta%e" fcurtC2n O':',ontt":s, ),::'.,It Ci-:ce'2cc(! ;::,<2 G;:i.r;i:lal rest le'/cl (Table 2, texL). 0)

"

I '1

i j '~ ~

:~ :j 1 1

A-7 2152 l'ritiua

Well Date Depth m. pH CO, HOD3 Cl S04 P K Na C. "g T.D.S. '1'. U ..

2152 9/7/68 7.6 1050 B09 101 4 4 750 66 76 2464

(field 1) 13/2/69 7.5 B,7 600 98 6 10 58B 68 45 1928

mg/t

lrell

?J 52

(fieli;. 1)

meq It

~ •

25/3/7C 7/5/70

25/5/70 Averase 4 s.:::l.'Tl)l~s

nat«

9/7/(,8

13/2/68

7/5/7C' 25/6/70

Depth. m

A,"erage 4 samples

o~ K.8. +

201+ + +

401+ + + •

601+ +

b.

pH

7.6

7. :: 8.1

7.9

8.1

7.9

co,

O .. I~

0.9

13 2'7

HC03

17,,2

13" 7 l!, .. (>

13 .. 8

857

8,9

89S!.77

Cl

22.8

16.9

15" 7 15.2

S04

2.1

2.0

,.1 2.2

558 149

540 105 627:!:91 113!.:lB

".

0.21

0.15

o.n 0.16

4 , 4!.1

K

0.1(1)

0.26

0.23

o. ?:l

lh.7::1 .. 3 17. 7!.2.6 2~41.().4 a.2lio.OS o. 21'to. 05

1970 1971 I 1972

9

8 at 2

N.

32.6

25.6

26.1

25.2

Gce

580 630:::'50

c.

3.3 0;.4

2.9

2.9

57

57 62:'5

56 to

':6!10

Kg

o. '.0 3.7 L.6

). r. 27.lf~1.6 3.J.:'0.3 4.6:0.8

!OOO

G.8:O.2 ) 9 2J~

2201. 3. 3!.O. 10

2J3C!.2(14

'otal ~otal ~otal anions oations ians

42.3

32.8

JJ.' ;1.8

42.3 32.6

33.e

~2.1

84.£ 65.4 67.1 6). S;

35.1!3.7 35.2!,.6 54 .. 7!6.9

.. 801+ 10,401248124

~ }' i , : ' , i i , , i i i , Q.o 14 ••• _-••• __ ........... -_ .... E +

I ! ! ! 'I ,. K Ha Mg Ca F Cl ~ I-fCO,

- .-E - .ORr." 100' +

120 C.s.

~~ll 2152: The samples analysed included no depth assigned samples. Yet, on 9/7/68 (above Table) one rather saline~ample was­taken, probably from a salt-rich section of the basalt. Thereafter Cave sandstone type is recorded. The chemical composition of the three cave sandstone type waters is remarkably constant. The rest level rexvered over sixteen months, but eventually exceeded the original rest level (Table 2). indicating that the regional rest level rose during 1968 to 1972. ~

I 'J

A-8

:::'<"':~

,;' c. o,

I ii;) .,~

< ,','

, .'-;- /,~"

mg// 3.'1 c,' c';'3

/le,' S2·

'1.:

'-;:;

~'::c

~ - ~"; 17 IS:

',~ ::~

2.;-

2 '7

7:;c::-t.'~, -;.

~" " .c ~ •• "

l::.{. ;;

116b "_

122~C

122 0 C

1220<.'

1,CQS

3 2,)~ 2

;:"? ::;~!J>_

_ ,_0 ....

l'~ ~ ;-

}l~. ?

'~<o:'

p:,

,<> 7

:- ~ 2

'. ; :' 05'

p:-l

[.7

: 6" -; ~ 5

70;

"i". S'

7. ')

S. J.

2· .. 2

7.1

y

Co 5

CQ r:.7 c·~ ~7

CC\

11,

:20

~~o

J..c

1:+

~3

27

::::::°3

C, ?

0 0 6

7. :'

70 '?

2753 (observation well)

:~:-:;O)

55

. :: ( ,,0 i,O';

:"05

:-" ~;

~, 7S

~,n

::1

1,70 1

.',- 7 ~ 1

1 7~ ('

1 7 ~ ~

:: ~75

J ,::73

6<,-:,

5c:3 },87

~;S7

6:>.:j

7")/

10536

'30, ..

6~o

7.5 2,,}

2.2

so

.;; ;,

~G0

::'10

105 lG<; 1;;)

He

2):;.

::':'2

" cQ:n (',,2}

c~ 1.1

Coo 11

C1::.

" " 2

2

2

2

2

2

1

1

y

C~21

Co 21

C.,,38

CG 3 6

K

5

6

25

15 J.)

1;:

13

~

50

"

1.)0 ."

:c.)o i

21.7

21.. 7

22,2

:;2

2.(,::'('

l05e ser scc ~'lC

52 ('.

52.3

713 5625

CP..

177

177 r,J.

~·l

4;; ;~3

1,8

:.; S~r.

0,

7~7

:. ::: 2.2

2.2

J:~

15 13

31 32: )1,

;'1.

o

22:;.

,,~

-'.,

1.2

i • ...

:::,.:e ~. S 2.e

7:'. J. S.

3'-52:

5564 ]. 761.

J. , "jl ..

1716

1 -, ~ .' -~

1(2('

: ~~ '7 2

1~:2C

?c~;~:

Tritiu.z::: T. U •

. :. c::c • ;:

C .. ~:::'C.2

1. <''':0 ~

';:'('1: ~ 1 ?c";"l :~~.~C':;3 c .'t.:c:-:::; i~;,:l

...... ' 1. c:::.:-:;'5. I, " , ~' ·0" 11C.C

27.C'- 26" ? 5}" 9

26. ? '?7. c 53,9 ')' .2 2, .. ;. ";2.7

J.:: 2~ (' 709 0 Q ;·7 , ., r -' ~"

meq/! 2~. ;;- ~ ~:~::- ,.9 c~ \7

C,.7

(..,,7

5.7

:;'07

16. S.

3~ L·,

./. ,. \',> '] J

C'Q33 1;0;: 3

C,,33

22.2

2:2.3

31. ('

~. 2

~. ~

?. E , ' •.• .1.

'::.7.C 27. ;. 5 '-. ;.

:6.;.,. ~7.2 5"'. £ ',- .- ,(c, J ::':2 ~:; f.~l J. ::;

-;-2 </C9 1 ;.:-' • .2 .s.l 0~S'

:: f::') :;::::- 701

C! "O;:Il

""'-~':;_~ = $E...$.--;:·:';"l"-"··-'i~"-· $-"-c-==-:-:~ f~:;"'''=-''''''' ! " ,:

1::1 I I. I'''''''''' I- .1

- . :). '-

'2.2

~_"7. :5

21.3

2';,8.1

1969

~~3 ('.)1

'..;: Co ('5

h.G OQ 05

1970

a ~2 4 e

Co 23

1.3

1971

'2 4 8 12

?!-L.. -S

1972

4

l •. =,

n.".:> \". "?

IF.3

3?,. C'

3'"';'. ~

:; ja ('

3('';; •. ~

'\ in\ 1 \

/ '1 ' , ~ 1> .. , ! !'; • ..,. ;ox:- ;; ;.",-,

';7, (' c,' ~

E t ,-:L

I\Hi

! >1 I . . ,

1;·:·lC<'>"~-1 . . ,

. i\~_". ,- i\ \

I [\ / i/l,~ i I ¥\, / "".,',.'~»-~~

I ~\\ .. ;t" .. " .. ;1 n", 1/ \".,,,, if

10 ...,--~ , , I i ! 'e' i' • . 0-.<:-.. Q' c_ Q_ .......

i:?CR~..r_,.., rr-o..--o"'''' '0 ....

t 1<1 I

t!""c: I!

i ~==i~~~ . ~r :--: ""'= \

I J=-:l~

;:-;c

~.;:

"'~: "'::-

mh \" 0" ~'

t \~ v:ii~ ;, ~, ". .. ,:J \./ ~

10; I L fi

, I L

~ i8(;,:~~,c-" /1)" l= 1 'Q-- 2Ej"

K No Mg Ca F Cl SO~ He03

~rcr.ole_2153 is the C8CP st core borehole at Orapa. Its geological section is a good representation of the geological seetlo!'). c.t. Q:::.J.?2., i:1cl'lCir:S the t:; per part of t~e Red beds 2.r.d 'Seed Shales. As is seen in the 2.bov~e Table ano $cctio!')., the top of the OaS2.1 :~::e?eill~d a :::at:he::: is;;1:! salir:e ... ,<!tc-r, the Ca','e sandstor:e yielced fresh -"ater, and in the R~c beds ':ery 5a1i:1e ',.-ater ";<='$ str:..:,.:: T:-'e Zlhove cC'::;f,los tior. dio.p':l7'": illL~st~':!tes these sali"ity dif:ercr:ces, ?C""t 8'.'81. "::r::':CO'ie-::'! ,.J<15 fast, essentially Qfter 8 r.10::ths .

..,''''~ '_F.'_"~F' ~r ',~ ~"r"~"_'~;~~'" ",~-,-,",;.. ..... -,,..,

h I

a:,

A-9 217{ re : c:,: ::l."te ~-3 ----~~c.

- ""> 20 ' ~ 1- ~ ,. ,-<3 .'. I

:Jc: :::: :- :-:CC_ Cl :.C,

i,U~' :;,2·1 -:;::0 ill r 63

'~/"'.~E: ~7. 6 -,! ~ .'if:

'-~: 70

ma / r ~ (

. ~"('

.-. :.:'1,:' '70

.2:: .'. ; -.~ ::.2 ' C '-1

"t·,· :..C z~.·~,~.c-'

7Iell Date D::rth,m

': ~- .

(:iel(~ 1)

rriea I f .. / ,

~ o C ~

.. ~ !:.}

~.' -""

: ~ /: :: i.:; ~ ':7. ·S -cl :J-.'0

,,-: J :.' ~':::

.c;:! <.' .'c ,; ,~/ le/ 7:-

~:

,).,! ',,'-'1

::'::> / ,/ :-~

;."'" ,_c le 3~.~~~le:;;

Cr ---: K.S. I .- I

2Cj + ,_! i"" I

~01-, ~ j

i 'i ~I'.,~. ,b. ,"" I ~:

sei + ~i i j. i I .;,

lCC !+ ... ! _~r:--:4 "

i"::~L..:: __ ·J ..... $.

7~ 9

7. '3 7~ 7

7.3 ;.;;-

7.7 '7 ~ is

:.5 7 ~ .~.

p:J:

7. I

7. ?! - S"

7 0 -;

{. :

7. :5 7.7

7..1'::

i" :'

". E

li,

20

13

~ "

13

C03

OA I;"

1.-".1- 7

c~ ;7 Co::.')

c. ;,3

CA:';'

C, ;;3

" ~ o ::::

.1.1;

~, ~,3

~!,2

51':' . ~ l

;,7...7

1_ ':C'

},67

!,52

1,3:;;' 7 ')

EGO}

6.6

:" S' ,. :. ?

[' o!,

7.:1. c " 8. i..:'''-

7. I,

-:.7 i . ,~

Cl

::. ~ 0 I,

loo ;;

J.,)."

:. -;.1

';"" .. ,

1'<;'06

1 : ~ 3 1·:>.2

::. ~ .0

7.l!O.5 ::'6~~ .. ::\'o

197 C

'.''':;

:'i.:' ;;\.~[1

523

.':6('-

5n s-<:; :'> ) 6{'6

S>?::~17

SOL,

:,.,<)

.' .• 7

i, . .(

.? '7

:'. J o 0 '. , :.J

"."-

). ';l

::25 , 00 Oc'

J.3tl

2:;-6

:'03 ::.oc 00' _.,' ')

~" ,

1 ·3

J.C!, -::- ~ 2

?

C'.ll

o. ].1

('~ 11

G. C')

C.ll

C'~Jl

Oh 05

i)" (\:;

('·.C<;

c. Cl

5.E~O.:! C.Jl.=C'.05

1 S 71 f 1 S 7 2

t. i3 12 t. a 12 " 12j . i • 'I ,-r-:~ '~C~~;:L .-1 ;,o,C",C. __ b

L .t:-,.-::.. ... ,,_ ..... e,,_-.o 20 L , 24 ~

I

, , •

, 2

2

2

1 , 2

1

1

1

2

c

::.:.,. ll~

15 1·:'

15 IG. 1.

E

:'..'l

e

l;.;C

.0.;.50

;~;~O

.'.:::'0

;c50

'c5 ),:, 5 ;,00

i,:,,)

i,<'::'

2~0.~ 1,·,'!.(,~7 !.,,5:'-;

, 0. ~·6

c. 0 S

c. ;·6 0~}2

C.U

c.;} 0.;:0

c. )6

C.36 0.36

!'Il.

J ? :;

~c c 0 C:

l? 1

:;'2.7 1 a C,

::'9.3

1S.:;'

:<C" C

:' 9.':, 1 C' ,~

~~

36 36 65

8')

[l,':

·3:.

73 ";,

s ;.

~ A""_ ··.'c-:,

c.

! .3 .• 3

". :3

:' .. ~ !". ::!

3. -

1,.3

iL.?

~. ?

~,'~

52 52 50

1.9 ;,9

1,6

Se :O:;f

-:'. J. '1.

J :, ,~~

162B 1%0

1675 :;'12:: ~ .:;

:. 572 :. 7(·n

~ '7: S ~ ;.;.(,

::.2:::":~.6 "~-~.

1~g

:,.3 c. __

/'.:"

i,.C:

1._.(,·

). S

;. '3

' .. ;;

'~. ,;:

h. S-

Totfll a~icnz

;::e.0

': ~. :

-::,s. L

r:.f.

,: 5. ~

?? ;:

:::8. -; ~?3

Tri"t-\.'..<.:r. T. ~r.

2.':>

:.2:::"0,3 1.5::'C-~2

c.:::'r.~

.~-('.2

Total catio::::s

2::. 5

;. ;

MO:

"'-c • .'

:2,~, >:

. ,~ 22-. -;

''C;,. ;;

'rotal :'cn:;.

;~. ;:.

. 6. '3

C: .• c _:.;;. ?

:) 5. :5

~ -' 0 :5 ~~

~.,. L

,,~

o.::.5!c.c~ 19,~~Co; ".}:-C.3 .'".3:::(:, '5 23.C:'c..s 25.1;:)..) 5G.J.~L3

100D~ I! '\', /-- ~ "'<'"

It f\ l.\' / .''"

/' ~ J ' -..:;;// lOOr I \. It:; f \7 'I \, ~.;: ,,';; ).

I : ~~, ,"".!; , . { If ~ D

1°1 l I if I If ! '-­K Ne: 1'-~g Cc :=

L

Cl sb~ H~o '~-..I~ ::::,. ~~?J:..~ ;:cV"0<.'1",{ only Ca.v'O!- '~i'!.!"!'.lst.one ':;<;'-.- \".::::;::"i.a;:ic':'.s in :'~l'~ SO" c<:.nter:.t:.

'N2.t.8:::" type in tr.c s2.:T:plcs ~.:,kef1. Tf~ei!:' CQ;,;'pcsilic:-:' is r2;..ar};~b1y ·:;onstol:lt, e;,:,-::~p:~ {er J '0

A-70

",ell D:l.te

'::27:· ;3" 1 (''' ."B

(:'~ e:: ', 1) ~:·:'1 {' .'~3

2: 1/1': '5$ J3,' 2/-5?

25:'3/7C 7.'5/7C

mg/l :~ ~/.;:' 70

23/€/:'C

2 7 ; lC.' 70

::! '2/71 2S/ !.:n

:2/5:'71 J 3.' 1.:'/ n !. \'.; ":;.' e 11

:;)c:;t.h, ::'I

! 5. :;

::.:,"'!)" le::.

E .. E

pr: C O ~.

7. 5

; . .... 7. 5 7.5

e.0 7.8 1)

7. ~ 13 7. 7 13 7.5 13 7.8 23

7. a 13

0,," ___ K ~

2cl·· / ··' 40" +, 50/" b.

: I !lO1 ' I , I

100/ , :1 120[- . ' i

/ . "

"0' , , 1.' ··1 :s~ , .... j' c. ,. 160'/ ·

-~-'

2775

iiCO~ : 1 SO , ),;2 ?~ 5 1/;.£

44C, C(' I "'-. 27

(70 ) ~1 : lJ, } (UC)

47C 5~2 132

4:;~ 6G:; 13 5 3° ') ~ ! J 135

425 £in 1 31

l:.17 6?C' 1 2':,

341 7'-. 9 153 41 9 7 ,;i, 73 !..25 '; .<'( 2 133 LOl 71:. 71

417 : 2., 659 '!:: Z, ? 1Z5~15

~

Trit i uJ:I ? K Na C. Ma T. D. S. T. U.

2 11. ; 1 3 ' . . . Up 1'" 7 ' . , . 2 1:- !.38 80 l.3 ! ~~ 2

(1 ) {6 ) (525 : ']!...3 ) '3': (~ ~.; .;. : 2 :.6 I. 53 7e 1.2 1 -: ~~

::' ~1:C . 2

2 15 50C 51 1.13 1 722

1 0 4 4E ~ :;3 3, 1 ~ :.C l .. ~ : ::, . ;

1 15 /,9C 59 3"l 1 .$2C c .. :::r. ) 1 " -" :;10 52 '7 1 5C' .!. ]. ~:;.3

1 15 550 C7 ., ' ~ o') - I ~_ C. L!.O::. 2:

1 0 5 550 !,~ !.: 1 792

2 1 6 520 7e- ).S 1 21'; Co C=- o: . 1 1 15 5'iB ~l :;:;. 171 ';

1 . 5~O. 5 1 5!~ . 5 50~~29 -;1 !. l(" 1. 0-:' ;; : 712 : 53

=r ,.--" j'\\ .,.~ .. "

$0.;: HCOJ

~, f "..... -

Ifl \~:\ ;ofl 'v*

I " • 1 fU"\ . J..Jt"" ! r" r:- ": ! No M!}

~ ~ -Cl

A "1 ... -1,

~7eJ I

2J75

meq /1

?1~"1',.. ",-11 ,t<;.. /::; {vonlv . .:

::In.'te Dc:,.t~~ ?:, 'CO; HCO} c:: SOl, 1> K !'le C. :'oto.l 'i'otlll 'l'otul anions ca"_io:r.1:< i?n~

8/10/6.';. 153 7. :; 6.h 20.1, 3.C O.l! 0.3£ 22.2 3.8 3.6 YO.V 5C.O 6(1. t'

~'/Jo/.s8 7. " 7.5 16,9 2.7 C.ll c.3/< l7.C 4.0 3. 5 2,/.(' 27. r. 5!,. :)

'2:./10/S8 7.5 C -J"\ ~ •.• I (39.·~) (2. 'i ) «(l~c5) (0.15) (3 ~'.::' ) ('.2) (C.:' ) (1.~,.5) (V,.1.) (;:s.r;1 )

13/ 2'/59 7", 5 7.7 16.7 2. S c.n 0.1,1 ) 9. 7 3. :;. 3.5 27. '2 tU •• l ~l. 3

7/ 5/70 3.0 7 .. 5 IB.7 2.;J o~ .:. J o.~8 21.7 3.1 4.0 29.1 29,1 58.2

2S! 5/7e 7.8 c".:... 6.4 17 .. I~ o 0 ~ .• v 0·('.5 0.36 2~ " 1'..7 3,,2 26.9 27.5 51 •• ::?

23/ 3/70 7.6· 0.4 7.0 l? 6 2 0 0.05 0.53 21. 3 3.0 3 •. 0 27.5 2-7. 7 55.2

27/JC/7-::> 7.7 0 .. r~ :; •. f1 17.5 o • '-~ 0 ,':,,05 C •. 36 ;::2.2- 2.6 2.2 27. ::. '2~. I, 54. S

?IJ 2:/71 7.6 c. !~ 5.6 n.1 ).4 O .. D5 c. ;.] 2 i" 11 CoL; 5. 5 3(".3 :,t'.6 ;,c <;:

'21..'/ 1.l71 8.0 0.4 0.9 21. 5 1. 5 0.05 O.U 23.9 2.4 3. '3 3r.2 3(". ) t)r.7

22/ 6/71 7.8 0.1, &.9 19~2 2.9 Q " 1 0.41 22.5 ;'.5 ).1 29.4- ??o 6 59.0

1]/1('/'11 6.6 20.1 1.5 0.05 0.38 23.4 2.6 2. -5 2-C.2 23.9 57.1

i,;r!,!"",,~e S! s<>..""::::-lcs 6... 8;:':) .. 1~ 18.9-:1.. 1, 2:.. G~O. 5 i"l.CI:"e:.02 0 .. 30:'-:).03 2203~1.17 2.9~.1, 3.1"!:.C.8 2804!1~1 28.4=1.2 56.S!2.}

'I;e-l 2]75: The o:1ly d£!:;-th ~~coroed snmple, a?pa~ently tll}(en while drilling (8/10/68) is from a depth of :'5.3 m. 1.e. f::::cm the top 0:::' ht:! bi'lsa:"t. Tr:e ..... z~cr is fr~<;h ano is tht.;.s .:!n 2x(J.>:1?le of fresh \"at~r f.ou:'.c. ccc;;Isiunally in the basalt. '1" .... 0 we:eks later" s,:-;l ne si:H:-.?le ~ypic21 of the sallne basalt \.;atcr variety .... ·as collected. This cew.onstrates the heterogeneity of the basaltic

<->q<.: f<2~·. '-:~<. '":li."~'ked compositicmal differe:1ccs a:r: .seen clea.r-ly in t~e CO:1'~loc.'ition diagram.

h I ~

~ to'

A-72 ')79 .. I TritiWl:

"l1eJ 1 Do.te Depth, m pH CC, HCO~ "" , SOl, P r ~,a C<). 1:1: T.;l. S. T. :re 2).1,

(fiel<.i.,l) 10/10/68 39.0 7.5 1,111 619 120 2 15 ;.75 65 ;·5 1576 lC/10/6S 6.8 (23 ) (1)";') (1%.) (1) C' ", (32') ) (126) (l ()) (2'--1. "';)

7/5/70 8.0 13 1,35 G15 105 , ::. ~) I.7e C, 1.3 175(-25/6/70 7.5 13 392 51? 156 1 1 i. J,:.;:; r),'. ,9 )7::1 }.7"!.r.3

mg/! 2,/6/7() 7.S 13 1.;71, 612. 177 1 19 '.;J0 ' ' .',1 l;>rr n

2l,./2.'1'1. 8.3 27 395 591 166 1 I, 510 4."5 37 :! 5;-::; O.G'!:0.~ ..... v ~ar.c 5 so.mple3 1.-31:'3<> 61?::':'_. 141::",,, 1.l. !.O. 5 lC'~6 490:::'15 ssze 3?::'2. 1717:~4

To-t~,J. Tot3.1 'tot ... l Well Date Depth pH CO_ EC03

Cl SOl. , F K Nil. Ca j.'g anions catior.s ions

2179 10/10/68 39.0 7.5 7.2 17.4 2.5 0.11 O~3g 20.7 3.:5 '.9 27.3 27.2 5: .• )

(~ield 1) le/10/68 6.8 '( o. sj OC.8) o~e) (0.0,) (0.10) (35.9) ( 6.3) (0.2) L;.2) (,.;. 1) (85.3)

meqlf

7/ 5/70 8.0 0.43 7.5 17.3 7..2 0.11 0 0 38 20~ 1+ )Q 3 3.5 27 • .3 27.0 ~I..~

25/ 6/70 7.5 0.1.3 6.4 17. ~ 2.8 0.05 0.36 21.1 2.7 .'J.2 26. :; 27.3 5':'.2

25/ 6/70 0.43 7,8 17.4 3.7 0.05 0.1.9 22.2 3.3 3.4 29.1 29.3 55. !.

24/ 2/71 8.3 0.9 6.5 16.6 3. S 0.05 0.10 22.2 2~Z 3.0 27.1 27.5 5L.6

Average ~ s~~ples 7.0=0.6 17.2+"0.7 3.0~O.5 0.07-:0.02 O.33"!-0.13 21. 5"!".C. 7 2. 9!"·O • .5 3.3:'('.2 27 • .s:!:.c.5 27.8~O.5 55.}!2.l

~ • • E

2:n L.O! ~

K,B.

501')1 o. 80 1-

• 'I 1c;r'1+-i . '-' r.' ~ I

120! : __ I iL.CL:._=J

c.s.

~ • • E

1 9 7 0 1971 11372

roof I jf; !~

","LiJ / \ ".l.~ r~ 11' \\.41::k:~~~·!i \ } \ .. --:,:;:4

X)! \ :/ ~ } . fi \ , I' \ I If-K 1:0 ' .L..... .

."<'ig C~F ~ -,,",'-' ~ 50, iI<!03

10 4 8 12 t, 8 '2 ' ! i ' ..

r" T V;'r . ..~ .. ~ _" .. ___ 0

-r-0P.L ~...... ...~.,

18 to''''·

h-=!'! ... ..2179: On the lO!lC/68, app2,~ently whtle drilli)"\g, :'::';0 sa~npl'2s \"1<:,;,12 te.k-~n. O;)C, at a degtl" of 39 n, i.c. in 't.he bas.::.lt, Is of. f.':esh ;,,·ater. The ot.hc:::: ::;arnple, h~'ls no .C"c~o::::de(.'! d,:,pth, bl,,:- Cc.ntdlns 13/9 rr.g/l Cl .a:od must, thczcfo .... 8, ::'c £:;:::Or.1 a :.",:'ine .... ·ater section in thE' !.:oasalt.. 'l'hes(" $am"les demonstrate ~;;e h(;:t":rO(J8;ieoI.lS nature of tht"! :c.:<.:salt uc:t:ifer. Five $c;"ples, l<!.;'~'r. Ju::::-in<; 1970-1-:;71, r~v(' .. ll. rat)::.er CO!lSt.:l<1t Cave s;;;.no",tone type w<:!t;Q):. R<!st level 1-0cc;. ... rery took i'l.::' m-:Jst on.::: ye<.:r.

h , -~

A-13

mg/l

rneq/f·:

':- - :r.!:e -;::CFtr., r..

::::: '~2

,;~·_·:6.:)

25/5/7('

7 / S/70

;".'"ell" Date Depth~ m

~.l '?-: - , ". f-;,~

.~: .~ 1)

;Q~J:-

!\ , / \

, '''/' '-c, """i E ,

/ \ i I ! i,

, '-W 'VI,'

r K 1'\:.:<

:;:-: CC;

7.2 7

pe C03

3:C03

7. S 8" ? 5 le ':3

/ / ,

~

/' /

\ / \ \--,.:.~/

tv.g Cc. F Cl SO~

2192 ----ECC Cl 3C. P , 4

;-: ;'a. Ga 1::g T. D. S.

le31 25(' Li.. 5 4 :;::0 70 61 1723

Tot:::l Cl S04 ? K Nn Ca J.:s a!'.io!1s

7,0 C. ,2 O.f-l 0.10 17.0 ? • s- 5. (' ~ j.

1970 197i 1 9 72 !

/"1-""

~ • " E

1,81248124 e , , t i i , i I I I

<~ o~~~o 1L..h- ORt. rr-"

~ p.. .... _.r;;,/ 20- p~-e...o,.. .. "

26t ,{

NCO)

;'i'~ll 21S2 j.s re,,)!:es'<'ntE:d by only op.e sa:-::lplc, che~1.ca ... "y close to Kalaha:::-i beds wate:::. o<.c£,:' level rz,co'v"ery tock about fou1."teen :"onths.

The s~pling depth is not kno ..... '!'..

Tritiill:l

.I..J.'.

~. 5:'(:'

Total cc.ti';:,::J.s

2S.:

Total i00 5

:. ;:

h­I

~

A-74 219] Tritium

-:>dl Date Dp.pth. ill p:I CO) nCO} Cl SO,. F K Ea 0. 1:g 7. D. 3. 2.'.U ..

2193 19/11/63 7.6 27 412 bP) 130 2 11~ 1;80 67 .~O 1'';':'0

(field 1) 2C/ll.i68 7.6 20 453 606 135 2 15 1.(,0 65 '4 16c4 1J./12/68 7.9 ( ll.) (192) ( 338) (49,) (1 ) (~ ) ( 6('-0) ( 59) (9 ) (E52)

25/3/70 I.! !:.(". :!: :

7/5/70 6.0 '3 442 602 120 1 20 i.50 74 59 ltn2

mg/l 25/6.'70 7.5 487 618 151 1 15 h75 75 1,0 1720 1.0:'0.3 n./ 2/;1. 7.7 2' 354 6C5 ISO 1 " l .. v5 43 1.8 :1 556 o. S!.O¥2

22/6/71 74.) 13 439 552 156 2 16 4~5 75 45 1;·56 Avel'n;;e- 6 sar.::pJ.es 431:!:32 6C4~5 1,52'.'.;15- . 1 .. 5:'0.;; 1J, :.; 471::13 6(,~9 !.6:'5 j ':'7)':'69

Tctz.l 'f'Qt'll Tctal Well D ... te Depth, Ii:c. pH C0

3 liC0

3 Cl SO~ ? K ITa: Ca Vg a:r.ior:.2 CG.:~i:::ne ions

219.3

(fidd 1) !~1!11/6B 7" 6 0.9 6.8 17.0 2.7 0.11 0.36 20.9

meq/I

3 • .', 3.1 27.0 27.7 5.'..7 20/1]/68 7.6 0.7 7.4 17.0 2.8 D.ll 0.3 6 20.9 3.2 3. >.> 27.7 22.0 ':: 'j. 7 11/12/63 (7.9) (0. 5) Cl.2 ) (15.2) (10., ) (0,05 ) (0.23 ) (26~ 1 ) h. 9) (e. '1) (2,]. C ) (3J.. 0) (';0.0 ) 7/ 5/7(1 B.O 0.1. 7.3 1-(.0 3.8 0.05 0.51 IS!. ii 3.7 l~" 9 2'3.2 2.3 • ..; 5~, 13

25/ 6/72 7.5 2.0 17.4 3. J 0 0 05 0.38 20.7 39H 3n8 2ij.6 28.:> ')(. 2 01./ 2/71 7.7 0.9 5. B 17.0 ).3 0.05 O~lO 21.1 2.2 1;..0 2(,.7 27.3 5!- .. 0 27/ 6/71 7.3 0.4 7,,2 16< 7 3.3 0.11 0.1,1 1? 8 3. e 3.7 27.1, n.S 57. 0 !;ver: .. ~~ 6 s4U'Ople>l 7. l!(I. 5 27.0!0.14 3.2~O.) 0.7S~~.05 O. 3 G~O. 8 20. 5!.O. 6 3.3:'0 • .5 3.8:'0. I. 27.6:0~6 27.9~0~4 55~5~1.0

on itB.

1970 1 9 71 i 1972

" B 12 • B 12 •

1000 L

I A 2T:1 l.O .....

$1~ ,,' , .....,.. i ',/ !.. i 601 'I b. 12 1\>"'-'I + I

~ ORL Q"'¥o""'''' e0 !+ .j.! '~l ..... "'-., ....

!!~ 1~-L d

ii \\ -" /~ •• 1()) 1 \ ~' ,.' o.

! f I \ j ,~~ VI \ ... :r~ 1 u! ,/ / .

-' "~I .. I <:: 10 ~ ~ ..... ~~ • !. ! E E looH 20r

, •

t 1201 . '1 ,(. 1:-: ~C,s,

1.:.._.J

We1,1. 2iS3: Or.e Sdl~~pl€.. of 11/12/h6 is of o:.Jtstz>ldl .. g COinpos.~ Orj~i;1 is hard t:o aSS2S<:. The othel.: six samples an;! of t.yp The rest. lc-vel H'.<;(' ste".d ... i.~· to 7 !'TI from the 8urfaC'e, whic~ out 5.'l t;,>2 t8:%t, it S'-,:C!T!S that: the Ca\'E; sandstone aq~l:1f"'r !.:; Kalahari l,<:::Js phrcRtic w.:..ter table.

10 ~ \/~,;: f ~ t I ; ! f 11( N'o MJ (.:= } __ ..;1l __ </. -

',,("6 HCo;

~cr. ('rc:bJ."" c.t r.hc top of t.he page «r.d t:cmpositicn ~i2.grarn) and it.$ c,:"l C,)'v'=! san-:!stone wate;. coro:posl\·.ion. s 8q:ll:~v,:.18nt. t,o t:h-;:} Shilllov,'est ;:",laha:::-i !:lens r2st l",vel. 1-.5 pointed ~o0m:L-.::rte:;';"iin, ::'av~:-:.g ~ts pi:O:7.o",.ctr:i.c b_~.aJ de-tena;':1cd by the

:t>. . -~",

A--15

irell Date

2182 21/9/68 (f:"eloi 2) 2 ...... /;/ ~S

21/9/68 29/10 / 6S

30/u i 6G

1/1~/ (,5

3/17./63

5/12/68

mgll 25/3/70 25/('/70

24/5/70

23/10/70

14/2/71

27/4/71

21/6/71

17/6/71

12/10/71

AverOlgG

Depth, 1!I pH

7.8 7.3 7.3 3.6

70.2 8.4 36.9 8.1.

88.5 8.4

7.2

7.8

7.9 7.5

7.3 7.7

7.9

7.5

7.5

7.5 7.6

20 sar,lple3

~ • '0 E

o r-; K.!>.

201 + + 1+

<'0\ -I- + 1 +

801~' + I b.

bOI~ 100)" •• ! 1L'OL~~:J C.s.

C03

20

14 20

55 21

35 55

20

20

13

7 6

44

2782 nG0 3 Cl SO!,. P

360 L9? 165 1 3')7 1.!.9 160 1 3')0 i,,)9 105 1

732 374- 130 4

430 338 95 l.

599 2% 100 2 732 374 120 4 I,C5 4S1 136 1

!~O5 485 125 1

!.O5 481 1 1.9 1

405 l,fn l!.9 1

402 1~83 196 1

1; 60 512 195 1

717 6e2 10C 5

417 ' . c J .• ".. :lJ 1 3":2 519 20"{ 2

5e8 507 131 1

517 494 135 4 297 490 191~ 2

428 493 12~ 1

466::'1(,0 z.60!60 1),.2::'28 2+" -<

i::; f; G . , c 70

III 12 4 8'" ... ... I, I L. 4 () .e- h'" I v 12 E ~~~'\,::C4~<';.V" rL-!-~

K

9 B

9 5 11

10

5

9

9

9

9 10 , 5

9

4 8

9 12

9 50:'2

1'rit.1= ~r::. ::::0. 1:g T. D. 3.

T.U:..

33C 95 57 1364 320 :;6 66 11.16

330 95 57 1}64

').'.0 ~C 26 1:>95 0 .. 3:0.2

2:;0 67 43 11&'.

380 39 :)!. P20

5:'<' 30 26 }'>96

325 93 52 11,00

325 95 49 11.60

330 95 52 1!.72

330 93 52 1.'; 72

350 89 53 1556 0.6:'0 .. 3

370 <)2 64 15F,s 1.1:(~2

51.5 6; 57 1952 L 1:0. 3

21)5 73 44 J 2CO 2.C~0.3

410 82 !; 7 1:,)6 0.7:0.2

371r 83 61 1504 O.4~O.2

40C 8) 5e 1556

3~8 28 69 lU'C'

III n 57 ::'I,IJ'

37t:'5B 7?~19 5:'9 IJ...t:;i'-~}26

1(,QJr I /~

I 1\ "~r, '~"2~ l'*- Jj.\ i:"..ry,.>:> [7, t,y,. }y~-.

;001 /f ~ ~'M" p"~';;~ l ~ ~.~ ;:~', f" ' if ,\",\~=L,~~,"" ~{

~ ;? ~.::::- - ;';'. 01, ~' I i \..-.-<-- _":.'11 0," " ~~.~

1/ i't toff. /if r h'· ! Cl f H L-. 7

1<' .-:----;-L-_ . ....L..L-__ J.. -~ •. - J

" :~o. Mg c-: r: Cl ~O ... 7-C0J

:r:,. ~

'­'~,

A-i6 '\'fell Da.to

21S2 21/ 9/68

(fie:e 2)211 9/f~

21/ 9/65

29/10/68

meq/l

30/11/ se 1']2/68

3/12/':'3

'5/}2/ ~,8

25/ 3/ i(\ 25/ (,.170

71,/ S''''0

23/H::/70

14/ 2/71

.?-/ 4/n 21/ 6/71

17/ ,,/71

12/:,('/71

Dopth, 8 pE

70.2

36.9

88.5

7.8 7.3 7.3 8.6 8.4 8.4

8 .. 1;.

7.2

7.8

7.9

7.5

7.3

7.7 7. q

7.5

7.5

-: .. :;.

7.6 AY,~!'":\_~c: 20 !Jnm:;-lt'ls

003

0.7 0.5

0.7

1.8 0.7

1.2

1.8

0.7

C.7 o. <.-

0.2

0.2

1.5

HC03

Cl 504

5.9

6.0

5.9 17..0

7.1

9.7 12 .. 0

6.6

6 • .s 6.6 6.6

6.6

7.5 ll.e

6.S 6. ;

6.}

S.5

! •• 9

H .• l

14 .. 1 IJ,.1

lOv5

9.5 8.3

10.5

13.5 13.7

13. 5

13.5

13.6 11 •• 1;.

P.0 9. R

11 •• 5

l'h ;;

13.9 1).2-

3.4 3.3 2.2

2.7

2.0

2.1

2 .. 5

2.8

2.6 ;.1 .:; .. 1

!,.1

/ .. ).

2.1

2. 'j

4.; 2.7

2.8

} •• O

2182 (contdJ F

o. o~· 0.05

0.05

0.21

0.05

0.) 0

0.21

0.('·5

0.05

0.05

0.05

0.('5

0.05

0.16

o. ('?

C.ll

o.o~

C. :'1

C.ll

K

c.'2; 0.2:

0.23

0.13

0.28

C. 2:5

0.13

0.:.?3

0.23

0.23

C.23

0.26

0.23

0.21

0.2,;

0.10

0.21

o. ?3 C.3.1

7.0 l1..0 2.6 0.05 (\.:<'.:<

7.5.!:~.6 13. ("!.l.7 3.01:('.<5 0.lJ::('.05 0.::>3:'0.05

N.

14.4

13.9

14.4

23. '5

12.2

1,;. S

?5. ;.

11 •• 1

llh)

14.4

1!1o 4

15 .. 2.

16.1

:2;.7

1 ~. I,

) -;.,S

l~). 3

'7 , ( ..... 1<).9

J I,. I)

15.3:'2.5

o.

4.8 4.3 4. S

1.5 3.4

2.0

~ • 5 h.7

1,.3

i,.7

1,.7

i, .. '5

h •. "

:~. ?

3. 7

1...1

1...2

l..2

1. I,

I •• !.

"" 4~ 7

5. !t 4.7

2.1

2.9

2."·

2.1

:,.3 h.G

1,. ~

1.. :;

4.3-5.3 1 .• 7

:. r,

.3. 9

5.0

1 •• 1

'3.7

;.. I

Tot::.1 Totnl anion.s cations

23.S 23.7

22.5

2 G." li.'. S-

2e. 'j 2 ";. ]

~~.1

'23. ('

2.3 • .3 2.3, .3 21 .. ')

:::::.1 31.3

1 S-. ':)

~ ';. 5

25.5

r.5 22.2

;;>Lf.

21..0

22.9

24.0

27. :5

F'.7

21.5

?'" ]

2).3

.5 2. 1

:;:3. '5 23.1.

2 -•• .3

2~. 2-

-~}. ?

19.9

:?~. 8

25.6

?:;'. ~

24 • .3

::>3.::-

3.8:'('.951,.2:'('.724.0:2.0 24 .. i!.2. 2

Well ll82: Three depth assigned samples were taken on 29/1C/68 during drilling. The upper one, from a d"'pth ef 70 m is still in th~ basalt section (geologjcal sect'ion of the well) 14 m above the C<>'"J'e sandstone contact., yet the \>:ater is ::.::csh. Ti:is is again an ex<.:n?le of fresh ~'<lter in the basalt. . All together 20 sa.l1ples were c!-)emically analysed, all revealing typical Ca"~ sand5ton~ components..

Total ion.'}

h-'.e

V:. 5 1,6.5

"' ~ "7 .-'.'- , .5 7.:; 1.2.4

5:' 2

!..~. I,

:-).1

l. ~~ 8

1,:'.7

t.~.6

<;? .5

5 ,:'. ('

3?l

5: • .3 " , , ...... 5:. I, .1;:7.1

I. ".5

48 .. 7!.4. 2

:t. I -0)

).1,-77

~'~ll Date Der>th. n:

ne) 2:1/9/68

(fjeld 2) 2:;,1J.O/~3

mgll

25/3/70 7/5/7e

7/;/70 25/5/70

?liB/70

2.>;/10/"/0

27/2/71

27/;./n /,vern2c 9 o~:n:;ll').s:

pr.

7.14

7,,7

7 .1~

7,,8

8.0

74 ?

7.1.

~eoll 1)a.to Depth~ IO pH

:~ ~ 3 ?j! 9(~·'':'

(-t:it':.d 2) 2;1 3/7C

7/ 5/7C 71 5/70

meqll

2'";/ t;/70

?J/ S/70

"J.S/IC/-7C

27/ . 2/71

27/ !;..In

AVC~3S~ 0 9~~pl-~

~ o ;; E

C=l K.B. I -; ,

2°1: ?! l.O! -:; i

1+ ;

601' ·1 b ·1

SCI' .1 i---! ' .• I

1001 •• I j- • I C.s. l:_'J

7.4

7.7

7.4 7.3

8.0

7.5

7. J~

C03 .

0.2

0.1,

C.I,

C.2

0.7

C03

7

13

13

7 20

SC03

S.l

6,8

G. Si

G.2

(.l

'. A 0. ;j

6.3

'" ,.

!lGD3

37h

1.15

42:2

375 433 385

417

352

412

I~02:!:.20

Cl

12. ::.

12. I)

lJ. G

12.7 _, 0 .I.,,..,,, 12. :>

,., f!3 .£.!..::L.

Cl

1.29

t.l.7

1,53

451

5('4

437

435

1.:-1. l. ~)Q

452:19

8°4

2.2

5. 7,

/,.1

2. )I

2_ Cl

1.5

50 I.

105

157 J 96

139

139

72 )_25

IG3

1')8

144!.30

p

12.3 ?.I~

J 2. B 3.:,

S • .;1

6~G=G.3

12.1 4.1

2;:', 7~O. S', ).0":..0.6

0.0')

0.C5

0.05

0.05

('.05

0.05

0.C5

0.05

(J.C,

o.o,,::()

1969 , 8

1970

17. 4 a 12 2 l' ! ! ! , , I , , , Z. v~~,~:<>'" ~. !:,> I - W ~'¥""

E - ORL

~

1

1

1

1

1

1

1

K

10

11

9 14

9

10

9

4

}:a

22-1,

"?S8

:., ~.('

?[S

360

?7l~

335 310

• •• _~ .'- ___ 0

(:a

86

?6 9',

96 63

9< 77

95

}:g

46

61 s;

,2 54

1·9 42

57

Tritium

T.D.5. T.tJ~

1258

) .'.43

1 ~, ).'.

1312

1756

) 300

1316

1392

2.2:'0.5

1.3~(' .. 3

2.C:'('.2

0 .. 7>.3

1

J.!:O

10 ;,OC' 9:' 50 9~:'6 54:'5

11·52

1'5 <' • • ~!:c. 7

C'. 8:('.::. 0.5:('.2

10:'1.5 31",::':;:6

x

0.25

0.28

0.23

0.36

O •. .' ~

0.26

O. ?~.,

0.10

0.26

(,:.2~O.01,

'rotal Total 't'o't .. l 1on~ N. c. Mg lUli"n~ e~tione:

12.3 ., , .- .. 1 ';. 2

1. ..,.'1

1 ".7

} 1. 9

11,,6

J 3. :;.

,13. C'

13. ':':':1. J

I •• "5

,,-,r.

! .. 7

I .• r,

/,_ 1

I.,"::

). n

I .• r h. (l

I.. 6!:('. 3

3. ~

".0 /-. ~

1.. ~

4.1.

4. (':

2('. <:

:: ~. ? ::1,. -;

n.0 2),_ 2

2C.4

}. :- 2<::.1

If' .., "'2.1

L.? ~".('

' •• 1,+-0.1. 22 .. 4!.2. 5

2('.·; "1 • ,~

-: ~. (C. 3-

':? 1,- ') I," ')

? ~. ') I,f, _ ;)

"'. L L " ,-• c

2r. S !.l.2:

:':::!. J 5::' .. 7

~3." !.5.1 ~':;.l r..l

2~.6!.1.0 45.o~3.S

lOOOfr ."". ~

10') ! \'. ~':;~ / ,,, ~1.!' ! "cv',

/ ,~.~" J " / . i

10 ~ f

I I ,L 1< Na :vI9 Ca F et so, HCO,]

"le1.l.2l.iU.= Th~ nine f.;amples taken durigg 1968 to 1971 are wH:hout. depth information. All are of the Cave sandstone composition. h­I -'J

A-78

mg/l

"',: '! l::' IJ3.~(,

2~.2;< 13/10/63

(~i(':'d 2) 11,;>')/S::'

2131.

C"'rl td.

25/3/70

7/'J/7C

25/G.'7~'

:.?,l7!7Cl

'/.:,/2/7C

23/1C/7(",

21../2/71

77/1./71

:;(!,t',. r.:

':'v~r"2'" 5' <Jump1"3

i'1'~J.l Date

;n.~l, ~:/~0/6.P.

(;'i'!J"~) :,-,'/:C/:;2:

·meq/i

~~/ :-/70 ;1 :;/,r.

?<>I 7/70

?J./ 8/70

::>3;'-;0/7(1

2'..1 ::'/71

27/ 4 1 71

Depthg t:l pE

~. (\

7. ')

7.7 7.0

7. B

7.5 :'.7

7 < 5

-'.5

p:i

8.0

7. ,7

7.7

7.9

7.&

7.5

7. ?

7.6

7.5

C03

C. S'

o. ~

("0.1"

o. '-)

0.;--

0.1,

G03

28

7

13

27

26

13

3:0;

? "5

? ~

7. ';

?.c'

7. ,!.

[I. 7

12.3

6.5'

7. /

2181; R(:(,7,

!';'l.fl

1..41

[,62

; .. 28

471+

5)1

7'))

423

1,67

492~72

01

11. 7

9. :? 9. ,;;

9. ? 3.? I,

9. ')

1 ':. 9

9. ?

Cl

1,l7

350

31.0

350

1,41

351

5';3

353 36,

392:51 ...

5C4-

5.5 P.).

i,.l

'!.7

2. j

1.'5

2.1

2. !;

10.2 2.0

"

'301.;.

265 390

196

Do

101

71 }('0

116

96 157:84

('.05

c. (I:) 0.0')

n.lr

0.C':;

r.13. (1.11

0.05

0 .. 11

?

1

1

1

2

K

ll~

14 10

9

1 10.

2 11

2 7

1. 20'

2 9

1 .. 4~C.5 11~J. .. 7

K

0. '15

0.~"';

0.2"';

0.<3 0. ?6

0. ::8

0.12

0.51

0. 23

N.

1 c,. ;.

1 ~" ('

1. Cl. 1

23. " p~

21 •• ':

1:. ~ ) ' 0 '.

::1\.

/,40

1,45

~0C

232

32r

278

57('

284

274

350~90

c.

2. ~

~. 7

, . , ::;.~

~. 6

).9:

2 • .;

~. 7

I .• C

Ca

56 51.:. 85 78

92 75

5;;:

7>

7')

72;:12:

f,~g

39

.0

.3

59

54 ,1 .7 " 7 .8

),6:6

Us

),)

'. , le.?

I .• :.

I" ?

3. n

~. 1

T. D. S.

17L!.

1743

1180

110.')

1328

] 1 '·4

)"'":('

)l7G

1250

, l.l('!.2~4

Total Totlll anioniS cations

')<;. "j ? 5. ~

~ <;. '. '2<;,'"

?1, 3 ')1. ]

1. co. oS 1:'. 1

"" ;"" ~ :;'. ~ (('. ( 2('. 3

~0. ~ ')"1. !,

jo::J ~ -:., .~

Tritium T.U.

1.7~C.h

3. 5!.('I. 3

1.2:('.3

J.S:('.~

C' .. 3!.r. 2

C.3~C .. 3

Total ions

CJ'. 5

;'1. J

./..:?!.

"-. ., ... ::, (I

(,C'. ')

6l. 2

';". ~

~. <:: -;or. (' :'0. 1 '. r-. 1

~v~~~&e 9 ~a~~1~9 13 .. 1:1.2 )].C~1.5 3.3~1.8 o. 07~(\. 3 0.28"':.0.09 1'\.~!3 .. ~ ~. 5~""'.'; 3.1?~(".'5 22.6"!-3.0 22.9!.3.0 45 .. 5:'6.0

t. 6 12 t. 8 12

i970 i 9 6 9 t ~, , '"' I , I i it, , I

~CR~ . ~~~~ r--~ ~ i 12 ~,:' E

~ell 2184: T~e nine sa~ples taken during 19G8-1971 are without depth recordings, and reveal ,_,. ",,-., variations ar'2: high, a pher:omenon not yet under~too:J, but cbsp.r\'p.o in several other

'4" i r,~'

>Xl' ,Jf'i:\~\·,\ M'. ,J~;J::: I if . ~. ,,,\:; -Y-'" !'Il ~.,..,.., f . fi ;,'!:' i

"r .. I K No Mg Ca F Cl

Cave sanastone composition. wells.

so. HCO, h I 0;

A-iS 2165 .--._---

',:;cll !;nte C~pth, l~. p:: CC) W;03 Cl SOl, F K ;!Il 'i~ ~tr; T.:). 5. Tritium

'1"- U.

2]B5 ~!11/6B'

(!'~.clo 2) l,ln/se S/l}/68

G/n/68

25/}/70

:/5/7e

mgl! 25/6/70

24/8/70

23!lO/7C

2/'./2/71

21:,./:.171

7.4

7.4

7.3 7.5 7~ 7

7.9

7.6 7.(,

7.5 7. I.,.

7 d 9

;,ver,,-.;-;e 11 ~ilm~1"'3

~·ol1 iJl;."te

::'1:-5 1./11/68

(field 2) l./n/63 ::..111(62

S/1l/72

2:,/ 3/R. 7/ SI70 meq/{

25/ "/70 2!J 5/70

:?3/1C/7C

21./ 2/71

2:./ L/71

Depth, ~ pS

7.4

7 ~ I.

7.3 -;.5

7.7 7.9

7.6 {. b

7.5

7.4

7.9

7

13

13 l}

CO;.

0.2

C. 4 0.4 o.!;

430 1..15

hoB

1.15

402

1,02

406

1 ... 11

390

)95

.399 t,07:::8

RCO~ ,

7.1

6.8

6.7 5.8

f.. ~

6 • .s 5.7

6.7

6~ I.

6.5

6.5

Cl

11..1

1.3.8

1).8

1;3.8

1 1,. 1

) 1,. 1

13.9

15.9

13.9 11;.6

l! .. 3

4%

1.90

1,9(1

4.90

501

502

h90

566 1.9 ;.

519

507 5(l1;~15

S04

3.2

3.2

3.2

3.2

1..1

h .. l

3.2 2.0

2.6

3.1 '::.1,

155 15S 155 1'.'3

1:;6

195 154

95 !z6

150

113 150:::15

F

0.05

04 ('15

0.('5

0.05

0.11

0.05

C.ll

C.ll

0.('5 (l<.05

(,.11

1

" l.

1

9

9

9

9

375

375

375 375"

7G

7~

76 76

}·.2

1..5

I,!.

4'. 2 10 388 78 1.7

1 9 36c 76 65

2 9 360 75 49

2 9 370 7J 61

1 9 360 73 49 1 I. 3)4 73 5e

2 9 360 75 53 1.t.!:C.S 3.6:tC.a 372:'9 7~!"·15 50!5

~

0.23

C'.23

(1. :?-3

0.23

0.25

0.23

(l.23

0.23

0.23

0.10

0.23

N.

15.1

16.3 Vi. 3

16.3

'1:::. S

15.7

15.7 1~. }

15.7 17.1

J'J. 6

a~

;'.-:< 3. ;::

' .• tl

3.8

5. Cl

3.8

3.8

3.5 3.7

3. 7

3. :'l

l!g

1,.('.

3. 7

1 • .:;

>. ">

5.9 :1.4-h.C

5.0

!.-# 0

4.1 I,.),

Ih2i3

1;· ~('

1',1<5

lu~O

1596

1599 1;.72

IJ. .'+0

:i~24

1472

1424 1466!.5C

2.7!.('I .. 3

2 .. (I!0.3

C'.8~C'.2

0 .... :('.2 0. ('!-o.)

~ot~l 'l'otal o.nion.s c:r.tio!l~

2).4

23.9 :n.,: ::'3.?

? 1,. ::

25.('

'25. ;'

24.4

2 ~ .. 2

2!,# 5

::C,. <;

2! •• 3

2L..Q

2!,#r

2L.O

2'

~:'i. (' ~;,. 1

".8 ~;:.. 5 .,?~.0

.0

Total ioes

I 7.4

47. ? ... ,. ':' J, 7. C.

!,::!.l,

S0. C'

1.2. C

49.2

45.7

!,.r..5

/,'. :;

11-,"":"" 1} :J~,,~te:::: 6.7!.O.1 ll:.2+-0.4 3.1·~O.·3- 0.07":"0.03 0.2:;:"_0.2 16. ?!.C-.! ::;.':::(' •. ,) l'ol!C.I,23.a!o.6 21h 3!O.448 .. 1!.1 .. O

~ o .. E

K.S.

i +

J-~ 1,01+ +1'

'+ SOi . b.

, + I i'" , 8'Jj .. !

1001 + .I ~

12Ci·· : '.]' , . '-"---

c.o.

1970 19£9 4 8 12 t. 8 12 I 'I;"

• I i 'I ~ 1llpo~RL' , , W 1t; E

1000

A .. f ~~,. 100 ~

10

I

L. , " , . , X No M!} Ca F Cl ' Sa. HCO:t

Well 2185: Eleve)1 samples haV'e been t.aken, -~itho;1t depth record!..ng. rE:;na:::~aj)l~i C(),·".,t.:!.r.t, .as is se<m in the cCiT1posi~ion diagram.

Ali are of lh~ Cav~ sandstone composition F which is b. J -.

'.0

A-20 ?<oo "'_ J,J tritium.

Cl 30 ? a !:Q. ~a :1.~g "" '" :- ";. Lr. ';'jell Date De'Pi;n, IT: pE CC. HeO) 4 J

2190 12/12/63 7.5 (7e ) ( 1 Cl.)'; (2.. 1;.) ) (1 ) ~12 ) (6GO) (S 5) ( 29) ( ?.~l C'~. (~i~ld 2) 25/3/70 1.7 402 483 157 1 JO '$13 ;?G 6: 11.76 O. B:C. 3

7 / S/7D 7," 5 4?.8 465 206 1 10 350 94 'J 11..75 2,..le/70 8.0 13 438 }.95 77 " 9 3hO 84 51 1:,12 G.5!.C.3

23/1C/70 7.5 13 390 399 108 1 9 2"5 86 1.4 ]2.',.C C. 2:( '" :? mg!{ 12/5/71 24.4 C'.1>.<:: 21 / 6/71 21.1~ 8.0 13 375 63!. 175 2 8 5cr 1.1 53 :;-:. ... 0

15/8/71 2:1.4- 8.2 25 358 564 86 2 5 "75 21 11 1344 Avcrase 6 31mples 399:2!.,. 507:62 1~5~J.,5 1. S:'o • .5 9. 2:~·O. 6 377"':74- 70:'26 ;,5:'12 l!.32:99

Toial Pohl 'l.'da.l. 'r.'ell Dc..to Depth. m pH C03 IlC0,3 Cl gOl~ l' X h~1il c< '" anions oll.ticn.::l 1on3

21S'C :~/1::/58 7. ;- (1. 2) (2~', :,) 0. c) (C('-S) (C. }C) ( " ' .. 1) ( ',. ::) ( 2. 1'1 Co,. c.) ( '.~, ~ \ . ". ! I (~i~ld 2) 2~/ 31]0 7.7 c. 'l 1 J. ~ . , ('.C",) 0.26 J3J J •• 5 5. c :---).)'" ?~. ) ,. -

7/ 5/70 7.5 7. t' o 13.1 1,.3 0.05 C.26 n.:: 1 .• 7 1,.1. :',. 5 21 .. 5 L?, 'J 2: • ..' S/~:O 3.0 O~ 1, 7.2 13.9 1. 6 0, "! 1 0.23 14.8 I. :2 i •• 2 :( ~.(' 23.1, 1.'>,4-meql! 23/lC/70 7.5 0.4 S.h 11.2 ? 3 ('.05 C.2) 'l ~.I,. c. J ;,. " 20.2 :'0.1 ,.c. ) 2]/ t;/71 21.4 8.(\ 0.1, G.2 17.9 3.6 0.11 0.21 21.8 2.1 ;,. I, 22.C 0- • ::;S. ' .. ~,;. 4 1~1 P:/71 '2I.~ ?,.2 CD ". :: 15.9 1. B ('" ~ I !).23 20.7 1.1 0.5' ::'{.4 22 •. '2 L 5.:2 Avera,;e 6 S:l:r:-.?lt's 6.5:.':0.4 14. Y!"L 8 2.81:.0.9 o. :~3:'0. 03 0.24:'0.02 1 i). 1,:'3. 2 3. 5::':: • 3 3 • ..,!:.] • Cl ~3.5:1.8 23.e:1GB 47.L:3.6

1969 1970 19 7 ~ /1972

, 8 12 , 8 17 , 6 12 , S ( I I I I : I I I, I I ,I I i i

O'L f- _~ ~ 12?'"~"""'- -- "'e, r---~ . , . ~ ~ ~, I

E ......... .. .... _f , ,0

20~ ,~/

looor' :".

J,," ~ I I'\; " . ,'" lOO I' . ".. ~'., ,,, I~ :;;u:;-;:

\ '~'" .' -/ .;, __ "'''' I -.,,~.

Y

· \\ p' ,';;~ -:;-" ....... ~ \ if ".~ ID \/~'.4 " I

11 r h-, ,;

J.i'g Ca F ..,,'~' • --::2> •. ~

i\'ell 2190: The earliest sample taken, on 12/12/68, probably during .:ir1111ng, Is saline and b'O!longs, composl'tionally to the saline basalt water type. ::Juring 1971 thr02e sa."1lples were taken with the depth so!:'lpler in the basaltic section, but the ~ater was fresh.

::to. ~ Cl

:i

A ~.

-·.cl

'.7-::1 J

;>::.<;::

(c,;>n td 4

mg/!

:r~ll

2J.9B

")~~e

27/3/70

24/6/70

2!J2/71

27/1,../71

'1.2/3/71

17/S/?!

12/10/71

De!J th , ;!:

91.· 5 97. (;,

], 5.3 30 • .5

n.5

A.c~~be 12 ~~~~lc~

p;.!

7.4

7.4 8.1

7. 5 8.1

7.6 7~ ,5

7.')

7.4 7. t;

Date D:::Vth, 1:1 pH

(rlc:!.~ 2)

27/ 3/70 15_3 30.5

91.5

97. (,

7.4

7.4 7.4

7.,4

B.l 7.5 8.1

I' meq! [

~

" " c

24/ 6/70 15.3 30.5

241 2/71

27/ 4171 17/ 8/71

12/10/7"l.

91"y

J:.'1flJ:'ag~ 12 5a:ll.pl(>e

o r--:1 K.S. 2[;\ + . . .,

'+ I loi+:lb sc(~ ,,: .. 1 r '-'u, • ; .... s.

l:.:j

7.6 7.5 7.9 7 ~ I.

7.6

co,

26

7

1J 13

25

trC03

395 348 230 L06

l,06

1;06

382

385

31.2 '.28

.3G4~1.')

2798 Cl

Sal

1.93

490

511

511 504

519 521

5C1..

,j95

501:l0

SOIL

196

121

95 131

133 133

169

99

159 125

139:!:-:::7

F

2

2

1

1

2

2

1

1

2

1

K

11

11

10

10 10 le

/,

10

11

10

1 .. S!'O.5 10!1

:'·"a

325

295 320 .

335 335 335

355 }Cl.

325 31C'

321"!.ll

81.

109

10h

31

97 lC'l

1('1

99 110

In 1{'"

1':$

60

61 52 51 48 46 64

55

5/,

61.' n~:(' 55:'4

1'. :i. 3.

I1d,4

11.24

1164 Ho !, 1536 l'..;>2

1~' ')6

1)76

lUW :>'45 6

::. .'.1 -;- ~J',

Total

Tri tiUlll

1 .. 1].

1.1!C.2

1. 8!O. 3

2.3"t(l.3

2.4!C.3

C.J!(,.2

0. 6~.C'. 2

'rot .. 1

COJ

EG03

Cl SO? r.. Nil 4

C. "s /iUlions oat:l.on~

'l'ot .. l 'ions

0.9 0.2

0.4

0.4 0.8

~ ~

;; E

1....0

6.6

6.5

5.7 3~a

6.7

6.7

6.3 5~ 3

5.6

7.0

6.0:0.8

A 3.6

... 13.6

11.~ 1

13.9

13~8

11 .. 5 1,,~ 4.

11..2

14 .• 6

14.7

14.2

11~~O

14.1:'0.3

2.3 4~1

1 ... 2

2.5

2.0

2.7 2.8

2.8

).5 2.1

3.3 2.6.

2_9:'O.f:

0.05

ColI

0.11

0.11

0.05

o. OS D.ll

0~11

o. C5 0.05

0.11

0.05

O.Ot(~,O.02

1959 1970 1971

t. 8 12 t, 8 12 I. G 12 t. f='"T'""'r' j i I!. j I I • I !-rr-I- 1 __

8 !'!>-Q~~..,-q 7"'~~ ~ '"

~2.k... CRL ~ ........

i- <!"" is t .o-_~_~ ... ~Q

0.28

0.28

0.28

0.28

O.ze 0.26 0.26

0.26

0.10

0.26

0.Z8

0.26

0. 26!.o. 03

IJ.6 11 .. 1

ll..ol

12.8

1 J. 9 11..6 1/ .. 6

14.6

14.6

13.2 14.1

13.5

14.0"!:.O.5

1.7

5.1

S.5

5.2

1.6 4.9 5.1

5.1

5.0 5.5 5.4 5.0

4,5=1.0

4.4 4.7

4.9

5.0

4.2 4.J 4.0

3.8 5,)

19.9

. 24 .. 4

24.8

23.0

19.7

23 ... 8 23.9 23.7 24.7

19.9

24.2

24.9

23.3

19.9

23.7 23.8

23.7 2L9

39.8 48.6

49.7 46~3

39.6

:. 7.5 47.7 47.1 ...

49.6 4.5 23.323.2 46.5

4.4 23.6 24.2 47.8 4.9 23.7 23.7 47.4

4.5~O.3 23.3~1~2 23.3~1.1 46.5!2.}

1 1;,""- .0> ~~:

" IW~I/K ~ if 03i::~~~ 1r \/"- f .

. ~ . ff IOL' l t1 !J

.x ,.:0 N ~, .;,-1 --r:-~~ , .9 Ca F cl sO; !ita, :t:. I

".> ·f:~ll 2lge: Dl.!r!"1g 1970 s~ven depth contro}l!?d sa;nples w-:re taken I fou.!:" in t!1e basaltiC' section I 5ands~o~~ type water.

~ut all revealed Cave -

A-22

2:!59 '.'})/OSS

(!':c]c. .5) 25/U/C2

26/~.l/66

?7/~1/68

2Bill/ cS

J.i .. 6

13.3

65.) 2.'3.7

37.8

1,.7. G

56.l

55~3

5).0

86.6 2;/11/-58 71~~ I~

Av~~~~p 9 3aealt ~~~?les

mgli

29/11/68

17/12/6'::

11./:?/6~

2159 192/(,')

cont-J. 15/2/0)9

5J/':/59

16/12/69

27/3/70

7/5/70

9/5/70

23/6/70

2~.,f!C·/70

2!J2/Tl

3/V-:1 27/1~/?1

17/3/71. 12(1..-'/7::'

A·.re::OiJ..0 e

92.7 95.8

'18~ 8

lOL9

103.0

I?/>. ,)

131.8

J.20.2

15.3

30 • .5

Sil.5

15 2.2

15·3 30 .. 5

n.5 97.0

15 .. 3

30 .. 5

91.5

28 Cave S~:-:~::I~vC:le :;:,.,.-:,::'es

8.3 .,. ;. 7.9

7.3

7.5 7.5

7.6 7.6

7.3 7.8 7.1;.

2.0

2.0

E.O 7.9

8.0

8.1

r.4 7.5 7.7 8.6

7.7 7.6

7.5 7.5 /?,.1

B.O 8.1 7. ! ..

7.3

7 • .5 7. '3 7.5

7 .. 3 7.6

7.7

7.5 7. 6 7 .. :;

(21)

'8 35 28

22.

23 21

21

:?B

31 !8

;.2

1,2

21

42

J5 28

20

51

26 l}

13

20

27

(76)

( ' .. C8)

577 60?

690

606

686

4 79 3%.

563 575:':;5

3 7 5

3%

39J.

36G

380

563 387 505 5).2

512

7L3

4"77

1.42

1,82

q5 415

469 251 ..

402 ',02

1,02

:.37

l,27

501

, 71

1.77

505

( 5%)

510

l~6:;!."'O _ N

:,t;P0

4061.:278

500

500

l,I3.3

1,'52

1.61

352 '.10

293 )Cl

307

331

32.5

268 2[;6

286 301,

33$

1.-93

!.-65

I,_G 5

l..33

291

291

)06

356

353

321

( 2344)

'292

36:J~7I.

?50

82.5

73r 523 207

775 743:'lN

73

:;. 73

81

R1

87 130

.';fi

Si)

"6

55

J.35

114 ::.;'1

129

147

118

90 235

~35

?:, 5

97 10(1

1~3

59

107

90 (;37)

8" ::;,12!.36

( 2)

5 ( 2)

4 ,; 5

5

5 2

2 ,

( ',) 10

17) 12

11

11

11

10

19

9

15

\ 550 ) ( 9)

?l;.3C' H7

(75) (3'))

2350 ;::'l..

2600

2GN'

2650

2l,.('0

2375 iTS 2750

2-fl

243 23(:

238

3f.6

84 305

(9)

1"

(%)

1 '-9

217

21 S

217 191

272 79 280

'l'~ 1)~ 3.

Cl ~,,:;)

7323

(13!"·S)

7:'>96

E 5tt.. e3E8

3717

77'36

~972

2n6

9135 4.3!O.7 12.4!.2.3 25'?5!.124 25l~-h6 221!-27 B51('!.Sf!3

2

2

2

2

2

2

2

2

2

2

3 2

2

2

2

2

2

1

1

2

2

2

I

2

2

7

7

7 7 7

7

7 6 6 6 6

7 8

9

8

9 8

10

11

11

11

7

7 7 8

2 2

2 7

(5) (10)

1 7

2!'C.3 8-:'1.3

)(;.0

3r.",

Po .' -3:53

3~3

315 }65 720

2,)0

290

505

310

250

290

2?O

320

298

298 335 335 2~5

282

280

?7h

2SiB

320

2e ,+

(1525)

2SS

318:~O

52

50 I,,?

52 43

51

'4 57 ;7 ')9

9

5]

52 51,

52 46

52 )0

102

104

109

53

51

57 60

U

I.S

50

4'

4' ,,0 42

41

40

3e 26

42 3)

39 40

57

54 70

57 58

62

39 1,1

'7

I"

52 52

:"7 1.8

(25) (224)

!,.') 41 5)~12 46~7

'J..'.!.2

l' ',2

]1..::' 0 13 50

1356

r: 72

1-·:12

1('1;5

1f'.flC

H'?6 151,0

1116

964 1 ('5 2

If'36 1(\68

1324

12)9 J :; ?"'

15('C'

151, S

113 ?

111"0

11:->8

1:1.32

1J72

1172 ( 5~61.)

H'3:2

1236:!:253

Tri t ium T.U.

1.1,:0.3 ).I.-:r.2

J..":'C'.:!

2.;>-:0.3 2.2~('.3

1.(,1.('.2

2.2-:'0. :3

2.1::'0.5

~.?~(-'~3 ~.~::('.;

2.1, !.'::'.l,.

2.3:!:.0.2 2.2!.(1.2

0 .. 7!0. 2

r.l.:!:.(,.2 l::. !

~

A-23

"ell Dn~c ~e:;,th, 1<'. pH C" V) ECO}

2199 18!~_1!6B 11.6

2;/11/68 :;'8~.3

65.3

8.3 (1.1.)

7.:~ 2.1

7.9 (C.7)

(17.0)

10.6

6.7)

9.5

'3.9

,i ""lOa I i f ( ..... : ~

26/n/68 28.7 7.3 0.9 37.8 7.5 l~Z

27/11/68 47.0 7.5 0.9 56.1 7.6 0.9

11.3

9.6 ~a/~1/68 65.3 7.6 c.9 ~. ')

7. "3

6.5 $."2

83.0 7.;' 0.7

86.5 7.8 C.7

29/11/68 7ih4 7~4 0 .. 9

A~e~~;~ 9 ~~za2t o~~?le~ 1.O-O~3 9.4 .. 1~1

29/11/6& 92. /

95.3

98.8

101.9 103 .. 0

1.26.3

17/12/68 131,,$

l!../ 2(59

15/ 2169 16/ 2/69

31/ .3/69

16/12/69 120.2

27/ 3/70 15.3

7/ Si70 9/ 5/70

23/ 6/70

23/1a/70 3/ Vi'

271 4/71

17/ 8/71 12/10/71

.~ ,".:):'::>.t."

30.5 91.5

152 .. 2

15.3

30.5

91 .. :;

97.0

15.3 JD~5

51. :;

23 Cavo ~'7.ncl.';OtQll~

:;;~"c:.ples

8.0

8.0

8.0

7~ 9

8 Q o

8.1

7.4

l~ 5

7.7 8.6

7.7

1.5 7.F.,.

7. :;

:'3.1

8 .. 0 8.1

7.4

7.3

7.3 7.5

7. 5

7.3

7~ 6

7~7

7 ~ '5

7.6 7.6

1.L

1.6 1.4 L4

1.2

0.9

0.6

2.0

0.8

6.1 6.0

6.l 6.0

6.2

5'.2

6.3 8.3 S.l.

8.4

12~2

7.8

:to. 3 7.9

7.8 6.8

0.1... 7.7

(J.t. 4.2

6.6

6. £

6.6 8.0

8.0 i3~1

0.6 7.~1

0 ... 9 7,,8

8.3 (2.5) (9.1)

8. J~ 7.5~l.O

2199(confd) C_'-

; .• 8)

105.6 (U.4)

104.7 IH.3

110 .. 7

116.8

105.6 12~. 8

33.2

S04

(3.1)

11.5

(3.9)

15.3

1702

19 0 8

17.2'

15.6 10.9

4.3

?

(0.11)

0.26

(o.n}

0.21

0.21

0.26

c.26

0.26

0 .. 11

0.11

131.8 16.2 0~21

114.5-7.815.5-2.20.23-0.4

1:~.1

11+.1

13.9

13·0

13.0

9·9 11.6

.8.3 8.6

8.6

9· .:.;

9.1

7.5 8.1

8.1

8.6

9. h

1309

13.1

13.1

13.6 3.2

e '" 8.6

10.0

9.9

9.0

\ 66" 0) 8.2

10.,,:'2.0

1.9 1.5 1.5 1.7

1.7 1.7

. 2.7

1.8

1.8

1.8 1.2

2.8

2.4

2.7

2.7

3.1

2. 5

1.9

!fo 9 4.9

4.9 2.0

2'.1

2.6 i,.2

2.2

1.9

(7.9)

l.B ;'~.3:::c.n

C.ll

0011

O.ll

0.11

0.11

0.11

O.l:!.

0.11

0.1:1

0.11

0.16

0.1::'

O.li

O.ll

0.11

O~ll

0.31

0,,05

0.05

0.]1

0 .. 28

0.::'0

O~13

0.18

(:~21

0.05

0..13

(0.2':;)

0.18 0.2'':.('1.03

x

(0.10) 0.26

(0.18)

0.:31

0.28

0.28

0.28

0 .. 26 0.49

Na

(23.9)

107.8

(16.3)

102.2

11;. (I 11;.0

l1:i.1.

104.4 :1.02.3

c.

(0.4) 7.3

(2. c)

11.7

lL9

12.2

11. 5

11.9 H,.3

Mg

(0.7)

u .. 7

(4.4) 16.4.

:i 7.9

n.7 17.9

15.7 22.t

Total Total Total :a...'1iODOS cations ions

('21..7) (25~2)

129.0 130.2 (23.8) ('22.9)

127.0 130.6

H? 6 143.1

142.5 143.2

1:./". (, HI..9

131.9 13202

145.0 139.4

(L9.9)

259.2

(46.71

257.6 285.7

235.7

2S~. 5

2 5!.. J

28z".1.

0.23 33 .. 7 4..2 6.5 .4-1..4 44.6 89.0

0.38 115'.6 15.3 23.1 :"57.9 158.2 316.1 0.32-0.06109.8-5.412.7-2.318.2-2.2229.4-20 129.6-10 259.0-30

0.18

C.18

O. :i8

0.18

C.1S

0.18

0.18

0~15

0015

C.lS o. ],5

0.18

0.21

Co 23

o? 21

0.23

0.2l

0.26

0.28

0.28

0~1.8

0,18

0 0 18

0,18

0.21

C.05

0.18

(O.26)

0.18

o. :;("'0. 03

15.9

16.9

16.3 15.7

15.7

13.7

11.5 12~ 2

12.6

12. IS

22.0

15.5

1l.3 12.6

12.6

13.9 12.5'

13.0

14.6

14.6

14.6 12.3

12.2

11.9 12.9

13.9

1"2.4_

( 6';. 3}

12.5 1! .• a!1.7

2.6

2.5 2.2

2.6

2.1

2.5

1.7

2.9 2.9

3.0

0.5 2.6

2.6

7..7

2. 6

2.3

2. I)

1.5

5.1 5 • .2

5.5 2.7

2.7 2.9

3.0 2.5

2.9

(1.3) 2.1

2.8:0 ....

3.6

4.0 4.1 3.5

4.0 3.3

3. 5 3. /~ 3.3

3.1 2.1

3.5

3.1

3.2

3.3

3.1

4.4

5.8 4.7

4-.8

5.1 3.2 3.4

4.7 3.7

4.3

3. ;:I

(18.1,.)

3. I~

5.7-:'0.6

22.5

2 2~ 5

22.3

21 .. 5

21.6

19.6

21.0

18.4

15.9

18.9

2,).8

19. a 17.3 18.8

18.6

19.0

19·9 20.2

24.6

2407

25.2

18.3

18.3

19.5 :1 9.4

20.5

1 q. 3

(8?.5)

23.3

23.}

22.7

22.1

22. C·

19.6

16.9

18.6

18.9

18.8

2l..7

19.7

17. :2

18.7

18.7

19.5 20.2

20.5

24.6 24.8

25.4

18.3

18.1.

19.6

19.9 20.8

1 c,;,

(86.3)

45.8

45.9

45.0

43~6

43.6

39.2:

37.9

37.0 37.8

37.7

4::'-.5

39.5

34.5

37. 5

37.3 38.5 40.1

40.7 49.2

49.5

50.6 36.6

35.7

39.1

39.3 1.1.3

)~.6

(168.8)

lB.4 18.1 36.5 20.5~1.8 20.5:2.0 41.0!3.B

h. i

t;;

,<:\-24

a..,. t.'r.J=o-;CJ4'"CO ; r-r--·-'~""'n-· ~. ,~.~:;:.~, ~~;;;--,

;t '11::1. ~~ . :1: !i:~ I· ~

2799(contd)

I

1969 1970 I I;, ,;,y- . . ! ,I t,\ \

I ' '1 ' .,. ' 1:-t. "';,~ ••

~ 'Or :t:. (. B i2 to 8

J; F! I I I I •

10Y)l /\. b; 1 Ii!i~ L o· .-i /;J!\.t: ,.."...,' \".'" .:.2"_

JOi)- ,,:If :\ r,'.... ~ ~ I ,. > \". .~. I~ ~" -'. I~"'·~ . '/" \~ If; ·JP_O

•• ~. I' / ' <\: •.. - .... r Ir·;~.i~"·~-

1971 11972 12 ;. 8 12 4

t! I j i I . I j

t ~r'; :1 ~.; I·.j ~[. i: !''-''''>1i«-"j,_ , .

~ ~ o - ~ .. .., ClI ORL "'o __ ~_ ... ~ E . •

"",,- .) I. .;

.,.;I.>:....--__ .C'·-"-___ --'

,: l:';:,;,S-.?:.;~J' -/1 V'JH>t

I 1'-;>'- n" .... r; W.I C .. n- ... "" .... k~' N',

TOr H f/ f-

Ir ;::,~ -//

'f ; i

/'( t!a . ,. Mg Ca F ! , Cl sa. -' HCO,

-..:r'll 2199: This well r.ilS bl?,en ' .... el} doc1.!tner.ted durir;cr cirilllng. The detailed rt:!5ults are given in the Ta01e on the previous ?<.iSC, a,.d in t;le cOr.1pcsition diagram <l:1cSillinity s2ction on th.1.r; pao;;C'. The fi:cst sample from a depth of 11.6 III revealed t,,![)iGa.l, NaCl-lo· .... , ",nc. !,a:-ICv1-hjg:J, ¥.o.la;'<lri b0d '\o'.;lt<2r. Then s,\.linc w3ter was encountered 311 i'l.1ong the basalt s8ction. 0;-;C8 \".:1e drill r,"achcd the C<;"ve sancsto;18 fresh Hate):" was st;:ruck, ;Jll along the sect.ion passed (salinity and geologlc31 section). L<lt:er depth s,:-rr:};·lcs :'d;;'(~n 1n the wcll were .111 of the Cave sar.osto;'0 tyr;8, ind.1cating the saline basalt. water w ... s fl .... ~hccl near the \"el1. Af>:er pumping ... ·o.s s:'opped in the field a s.;,:~?le taken on 17/8/71 was again saline, of the saline bilsdlt type. Ap?arc:;.tly the 50.11]";1.' basi.'l~_t · .... at'?!':" rr!o';cd into the well, filli~,g it., .:>..~d the sampl(" "le'S takEin il'l'~-nediat€'<ly after thr.., punp was stdrted, before the well coin:1:!) '."as pro.?erly Cusned out. T·,;o :Tlo'lths later Ca .... e sands1.one water was COllected, apparently ~ftcr proper w;;\shout- of th'£' well column.

:h. I

1\,) .:,

A-25 ;.'ell

72('6

C"ic?ca 3)

'1 rng I'!

D;:o.";e

:O/j2/68

3 :J:o. 2/ 63

2/1/69

18/2/69

20/2/69

27/'3.170

9/5/70

23/6/70

22/8/'70

?;/10/70

21.12/71

271 !..i71

21/6/71

12/10/71

DC')'!;:l, m

l.JJ .. 9

!..::.7

I. 7. (')

5C~ ~)

.'i3Q 1

55'. ?

2:::~ ;; 65.3-7l~ l.

0" -~~.(

],01.9

100.0

15.,3

30 0 5 15.3

30.5

J 5.3

3".5 15. j

30.5

.!,.ver-age 26 :"t,l:.,'llcs

~

O<"";ll! c :-"'1>0'" __ _

r----u·"·~' -l ;:f' , j: ::1 11

;;, \- 'I t'<IM~

_"i:'c4 I ~ $Or !::~\ "' .• A j" f ~ ~~ : I. ·lc~,---" ,,~ I'! 1

t~~K :>1 ! I ""1 -;t~L:L.-.-J

pr:

7.9

7.9

7.8

7. 0

G.5 7. ;.

7.9 "lJ

7 .. 'J

7.8

7 .. 9 7.9

7 .. 1.,_

7.1,

7. r.;

8. I

7.5 ! > I,

7 ~ !;

7. !,

7,7

7. 4

7. 5

7. !.

7.5

7.2

7. 5

C03

(27 )

27

1.1

27

27

27 20

l'.

::0 20

20

20

20

"/

7'

7 1

6

ECO, ,

(2,3; 290

'277

373

n9 1.1.3

3'!'~

1, G1

l4e L2-~

1,.23

1..1,8

~'C5

505 5(')2

'+28

.522

515 1..-87

!,,)1..

I.Sl

491 4$,',

J,.91

506

491

2206 ---Cl

(137)

"11, S

6GB

3.'~ 1

417

402

(,?3

3D~.

371.

395

395 31-5 ~·(l3

29;'

?i'<b

233

286

n-';

23/,

29J~

2~J :,

3('[,

306

403

so, "

(I!CO)

3 7~)

"75

275

ns ?75 ;:'35

9;;

95 85 35 85

710 71

;18

78

93 98

93 1~"J8

:log

J.00 ,­-, 135

379 7~

J~52 173

567 51)

?

( 2)

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

1

1

z 2

2

1

1

2

1

K

(1])

l'

8

7

S

8

9

e S

8

S

8

8

8

S

8

5 9" 8

s

510

445:57 391"!-94 ]}a!.70 2 to .. ;;

12

8

S

2e

8

B

9

9"!-1

1969 1970 19 71

i..312~S121.13 4 rr-r-r , I

f! I t a. ORL+ e. __ .... _~ ... #$o ..... o .. ~ ...... G>

"'.; sr E

11972

12 4 j-.--rf

•

N ..

(78) )

52('

1:5('

~80

3PO

3~O

5:;t~

315

3J.~

315 311;

290

275

275 270

27r,

290

230

. 274

27h

282

275 272

3 I I. 280

335 390

329:'57

Tri tituil

Ca ).;g T. D. s. . T .. u.

(11,(') (n2)

85 E'i

"1.

25 72

5:?

" 64

52

5' 5'

59

57

57 I,'f-

59 57

53 53 2)

50 52

65

137 8(',

5S

6'

55 6~

51 43

51 )1

41

kC'

~8

", /,1

37 "18

39 /.6

.h9 1,7

42

60 7(' 59

75 73

83 69 ~8:11 52!.:n

" ri h',

L If H:, f,~

( 3('241

2(',:('

1r·?

1"';8-1.

:;.1-16

161,.' .. 1(('0

] lfr'

1175 11 :·8

111,3

1('Ge

H'72

lC'I,~

101,4.

J.('.J~

1[' ~:1

IH\S

1056

1124-

113-5 ~ 2;,6

1036

n03

l'~ ~C'

137<!

153 G ) 27';:!:219

2.1...>.3 2 .. ) :!:(' .. I.;

3.3:!:C.j

1. ';!.0. 2

1.71.0 .3

1.?!.C.3

1. 6!.r. ~

('.6>.2

r';:'.3

I , . CO F Q .so, H::DJ

):". I ~V {jj

'.4-26

iY"ll !la te :i:lepth,!!l ;OH C03 liCC"

J Cl

2206fcontd) ------

504

p ~ N. C. l1g '1'<:'lt~l 'rota.! nnionl!l oa:tionl!':

Total ions -_._--

2z06 }C/12/68

(t'ie:d ?)

31/12/68

2/ 1/69

18/ 2/69

20( 2/69

rnea I! 27/ }/70 • 9/ 5/70

23/ 6/70

22/ 8/70

40.5'

1 .. 2.7

47.0

50.0

53.1

5J.2 22.9

65. :3 71.4

89.7

101.9

lOS~(I

15.3

30.5

15. ") 30.5

;0.5 15~3

15 .. 3 30.5

7.9 7.9

7.8 7.9

S.5

7. :' 7.9 7.6

7. ':;

7.8

7.9

7.9

7.1:..

7.4

7.6

8.1

7.5 7.4 7. h

7.4

7.7

7 .l~

(C.9)

D.? 1.4

0,9

C.9 0.9 0.6

0.4

0.6

0.6

0.6

0.6

0.6

(4.3)

4.8

1 .. 5

6.1

4.1

7.3

5.7 7.6 7.3 6.9 6.9

7.3 8.3 8.3

8.1

7.0 8.6

8~ I ...

8.0

C.l 7.4 8,1

-(38.7)

21.0

18.S 10.7

11.8

11.3" 19.2

10.7

10.5

11.1

11.1

&.9 8.5

8.3

8.1

8.0

8.1

8.0

8.0

8.2

8.3 8.7

8.6· 11.4

(8.3)

7.8

5.7

5.7

5.7

5.7 .1 .. 9

1.8

2.0

1.8

1.8

1.8

1.5

1.5 2.0

1.6 2.0

2.0

1.9

2.3

2. )

(D.n)

0.21

0.11

0 0 11

0.11

0.11

0.11

0.11

0.11

Q.ll

0.11

0.11

C.ll

0.11

0.11

0.11

0.1).

o.n 0.05

0.05

0.41

2.1 0.11

1.3 0.11

2.6 0.05

1.7 0.05

(0.25 )

a •. D 0.21

0.18

0.21

0.21

0.23

0.21

(\.21

0.21

0.21

0.21

0.2]

0.21

(3JH 1)

22.6

19.6

16~ 5

16~ 5

17.0

22.6

13.7

13.7

130 .,

13.5 12:, 6

12'.0

12.0

11.7

11.7 12. :5

(7.0)

4 • .3

1..3

(l0.9)

7.2

6.6

4.5

5.2

4.5 5.1

4.2

3. 5 4.2

4.2

3.4 3. ;; 3.1

3.5

3.4 3.0

3.1 3.2 3-.8

4.0

3.9

3.5

5.0 4.8

(51. q)

34.1 29.9

23.1

22.1

24.9

30.2

20.4

20.3

20 .. 3

20.6

13.5 13.5

13.1

18.4

17.0

18.8

le.6

18.0 18.4

18.2

19.0

20.1

22.4

20.7

(52.3)

34.4 30.6

23.8

23.1

2;.3

25 • .(,

20.7

20.6

20.7

20.5

18.8 18.4

18.2

18.3

17.5 18.8

18.8

18.0

18.6 18.1

18 • .3

18.1

22.4

20~7

(104.2)

68.5 60.5

46.9 45.2

50.2

55.6 41.1

40.9

41.0

41.1

37.3

36.9

36.3

36.7 31... 5 37.6

37.4

36.0

,P.O

36.3

37.3

36.2:

.1.4.8

41.4

23/10/70

241 2/71

27/ Un 21/ 6/71

12!lO/71

7. )

7.4

7~ 5 7.2

7.6

0.2

0.2

0.2

0.0

0.2

7.9 8 .. 1

8.3 8.1

8.4

10.7

12.7

16.0

3.6 0 .. 11

0.21

0.21

0.23

0.23

0.23

0.21

0.31

0.21

0.21

0.51

0.21

0.21

C.23

12.6

11.9

11.9

12.3

12.0 11.3

1".7 12.2

14.6 16.9

2.6

1.3 3.6 2.6

2.6

3.2

2.6

2:.5

2.6

3.0

2.9

2.9

2.2

3.0

2.9

2.7

2.7

1.5 2.5

2.6

3.3

3.5

3.8

4.2

6.0 21,.6 21 •• 5 49.1

1.B 0.05 5.7 26.2 27.0 43.2 lI,,-.,r!J..g" 26 !St\!1lpletl 7.3~0.9 1l.O!.2.7 2.9~1.5 O.~1:O.C2 o. 23~ .. 05 14.3:2.5 2. 9!.O. 6 ~.3~.9 21.5!3.3 21.5!3.2 43.0~6.5

~£.!.L~206: In four di!Ys, from 30/12/68 to 2/1/69, whil~ drilling, repeated c_cpth samples were taken ('fable 011 previous page). It. is seen (cb1orinJty <lnG. gco1ogi~~~1 profile) that one rather fl"Cesll water was encountered in the bas.::.s.lt, at a depth of 23 rn, b~t a t,yp:!..cal saline b~salt .... fater was struck at the base of the ba!;<.Ilt. In the Cave sandstone fresh water was found all along U:<2 e) ;r. drilled in it. ::'.206 is t:-.s best yieldi~g '1.'..:.-11 at Orapa. Possible rei'lsorts vxe (fl! it is locatBd on the upthrown side of .::. fa.ult, (b) the ba:-::alt secLic!"'; _is mlnimal and (c; the well is lccated on thEO dry :::,etlhakane river. h

I

~

, i

/1-27 Townsh~!) 9

":~ll D?"'.:e ,:'e,. t"., :T, p:: se3 ;-:::°3 Cl ~01~ K ;.:1 C, j,:;;

9 25/3/70 7.5 ;36 519 59 2 10 .25 67 )5

,:,.c7fT:!J~.ip 7/5/70 7. e 629 31.) 51 2 7 -ni; 61 51

25/6/70 8.1 13 257 511 l~! 6 1 11 1 .. 15 13 3/,

2;;/6/70 7.7 7 . 239 45? 113 1 9 360 8 " 12/5/(l 21.4-

mgll 22/6/71 21.4 7.6 581 223 5" 3 9 26c '" 35

51.9 7.3 72. 223 .3 4 4 285 72 /.1

1 (,!a!71 17.1 7.8 1.1~ 1,01 302 17 1 18 305 " 24

A,,::rae~ 7 :3D'":[j?le3 48:1.:'156- 368!.lO8 6S!.31 2'!:.O.9 10:'3 31 .. 1:''jO 4(':'23 32:1.8

Well D.!tte Dopth, m pH C03 BCG} Cl S04 ¥ • Na C. l<g

9 251 3/70 7.6 8.8 14.6 1.2 0.11 0.26 18.4 3.4 2.8 'l'olrn"hip 71 5/70 7.8 10.3 9.7 1.1 0.11 0.18 13.8 3.1 4.2

251 6/70 8.1 0.4 4.2 14.4 2.6 0,05 0.28 18.0 0.7 2.8

meql!

TO;>"nsn 'f'~ Kalana

231 8170 7.7 221 61n 21.4 7.6

5149 7.3 16/ 8/n 17.1 7.8 Averag~ 7 sample~

~; Alnost no infor::lation i5 ava position of s3.::lples takci1 dt:ring: i Dei:;; 'Io,','tter. The'!'"c: is evid~r:ce

0.2

1.5

3.9 22.7 2.4 0.05 Q.23

9.5 G.} 1.1 0.16 0.23

11.$' 6.3 0.9 0.21 0.10

6.6 8.5 0.4 0.05 0.46 7. 9!.2. 6 10 .. 1~!.3.0 1.4!:.0.7 0.11+..0405 O.2t;:.O.08

1001- J ~r \' '\>. &\<'-/. r IJ "\/~:~ l \ \! I

~~ ~~"/ J . I ,~~!/

.. / I

M'. ,',

/ , ,j

r. ,Vq Mg Co F Cl So. HCel

15.7 0.4 0.4 12.2 0.2 2.7 12.4 3.6 3.4 1}.) 1.1 2.0

IJ;.St.2.2 2.1to.2 2.6:'1.5

l<l.blc on this .,·;ell. 970-1971 is g,~dual1y hat t.h';: well caved in

lo""er .in Cl as if passing from Cave sandstone ,,'at.er t.ype to and that. sha)lowel' wat€'r .... 'as pu:r.pec:!. thcreafte:!".

Tritiu!>I

'1\ D.~. T.U.

1552 1.0:(I.~ 1201+

1 ":,('

1120

O. Z!.(,.l

9,,8

HOO

961.

]175:'::.63

Total Total 'l'otal !1nions oQtion~ ions

24.7 25.0 49 .. 7 22.1 21.3 42.4

21. 5 21.8 1.3.3 19.2 16.7 3'5.9 17.1 15. :3 32.4

19.4 20.5 39.9

16.2 16.8 35.0 1946:2.1 19.6~2.9 39.2~5eO

~ I

~

A-28

Township 10 Tritiu!:l

·.'!c).l Date D~?th~ m pR C03 HOO3

Cl so .... P K tt'a 0. l.'!; 1'. n. s. LU.

10 2.5/3/70 7.7 5119 365 39 2 9 265 91 "" 1160 1. 3!.('.:3 Town-;i";ip 7,' 5/ 70 7.9 13 51.9 64 59 2 4 160 1,8 ,6 7!.,3

C'.$':0.4 2'/6/70 7.6 558 71 26 3 4 160 53 28 724 mg/ { 2-::/6/Tl 7.3 538 73 15 3 4 170 <1::> 18 n2.

:·."'IO'ra:!,c 4 3"-.'l'ples 56}1:.15 143:'111 35:1 4 3"!:O. '; 5~2 F.:~:)5 65!-14 32-:'9 cL(':l;('

'l'otal '1'otal :.'o+,al iiell. DIl.~e Dopth, :n pR C0

3 RC0

3 Cl S04 F K

,,_ Ca Mg aniOlllS o;..tionll 1on~

:e 25/ 3/70 7.2 9-.0 10.3 0.8 0".11 0.23 11.5 4.6 3.6 20.2 19.9 40.1 ':'ovnship 71 5/70 7.9 0.4 9.0 1.8 1.2 0 .. 11 0.10 7.0 2. " 3.0 12. ") 12.4 24.7 25/ 6/70 7.6 9.3 2.0 0.5 0.16 0.10 7.0 2.7 2.3 12.0 12.0 24.0 meq! [ 22/ 6/71 7.} 9.6 2.1 o.} 0.16 0.10 7.4 3.3 1.5 12.2 12.,3 24 .. 5 Av!:;r-otg~ 4 E:ll.tlple~ 9. i!.o. 3 4.0:'3.1 0.7:'0 .. 3 O.16!o.03 0.13:'0.11 8.2:1.7 3. 3+~0. 7 2. 6!.0 .. 7 14.2:3.0 14.2~2.9· 28.4:5.9

100

. r' /t'0. /\'~ .

1\ "" I \ A ~\ / ... ~.. ; /; .,'v</,.l;:~ : f\t, \/ . I 'j' "'" If "',j

I ! -". 1000

, I ! I .) , r.----l K No Ng ca F Cl S04 riCO]

?O·"'!'.S~\.:hLl:Q: No 1nfo::mat1on iz available fOr th1s well. T:-:'c su.:-·plcs tak""n during 1'"::70-1971 show a s!:i1ilar picture to tha.t found in Townshi.p 9, but more extreme. Th!;"! f1rst sample 1s of C'-WE: sa!1.zistone comr;O£.1"!:1o:-:. ana the other three of typical Kalanal:! beds composit1on. In view of the lack of any other data, i:1ter?r~tat.ion is ir:",possible.

h I ~ Co