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I I I I I I

REPUBLIC OF BOTSWANA DEPARTMENT OF GEOLOGICAL SURVEY

MATSHENG AREA GROUNDWATER INVESTIGATION

(TB 10/2/12/92-93)

TECHNICAL REPORT T8:

HYDROCHEMISTRY OF THE MATSHENG AREA

AUGUST 1995

Prepared by

WELLFIELD ...... -.. ~ .. INTER ·~~CONSULT

in association with

BRITISH GEOLOGICAL SURVEY Keyworth, Nottingham, UK

MATSHENG AREA GROUNDWATER INVESTIGATION Technical Report T8 August 1995

LIST OF CONTENTS

1 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

2 DATA ................................................................ 2 2.1 Data Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2 2.2 Sampling Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2 2.3 Analysis of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 2.4 Spatial Distribution of Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 2.5 Representation of Aquifers .......................................... 5

3 GROUNDWATER CHEMISTRY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 3.1 Chemical Evolution of Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 3.2 Kalahari Group Hydrochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8

3.2.1 Na-CI Water Type .......................................... 9 3.2.2 Ca-Mg-HCO, Water Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 3.2.3 Na-HCO, Water Type ...................................... , 10 3.2.4 Ca-Cl, Water Type ......................................... 10

3.3 Mosolotsane Formation Hydrochemistry ............................... , 10 3.4 Ecca Series Hydrochemistry ........................................ , 11 3.5 Spatial Distribution of Water Types .................................. , 11

3.5.1 Kalahari Formation ........................................ , 12 3.5.2 Mosolotsane Formation ........ , .......... , . . . . . . . . . . . . . . . . .. 13 3.5.3 Ecca Group .............................................. 14

3.6 Hydrochemical variation with depth .................................. , 14 3.6.1 Variation of Conductivity with depth: KalaharijMosolotsane

Formations .............................................. , 15 3.6.2 Variation of Chemistry with Depth: Deep boreholes ................ 15

4 HYDRO CHEMICAL CHANGES DURING TEST PUMPING .................... 18

5 TEMPORAL CHANGES IN HYDROCHEMISTRY . ...... . . . . . ..... . .... . . . . .. 20

6 GROUND WATER WATER QUALITY AND USAGE ......................... , 22 6.1 Drinking Water Standards .......................................... 22 6.2 Groundwater Quality in the Matsheng Area ............................ , 22

7 DISCUSSION ......................................................... 26

8 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29

REFERENCES ....................................................... , 30

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MATSHENG AREA GROUNDWATER INVESTIGATION Technical Report 1'8 August 1995

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TABLE 1 TABLE 2 TABLE 3 TABLE 4

TABLE 5 TABLE 6 TABLE 7

TABLE 8

FIGURE 1 FIGURE 2(a) FIGURE 2(b) FIGURE 2(c) FIGURE 2(d) FIGURE 2(e) FIGURE 2(t) FIGURE 2(g) FIGURE (3a) FIGURE (3b) FIGURE (4a) FIGURE (4b) FIGURE (4c) FIGURE 5(a) FIGURE 5(b) FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10(a) FIGURE 10(b) FIGURE lO(c) FIGURE 10(d) FIGURE 11 FIGURE 12 FIGURE 13

LIST OF TABLE

Generalised Geological Sequence within the Project Area . . . . . . . . . . . . . . . . . . .. 1 Correlation of DGS and GRES II analysis results . . . . . . . . . . . . . . . . . . . . . . . . .. 4 Results of Regression Analysis of SEC and TDS . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 Classification of Water Based on Specific Electrical Conductivity and TDS ........................................................... 8 Variation of Hydrochemistry with Pumping ............................. 19 Water Quality Standards: Drinking Water for Human Consumption ........... 23 Electrical Conductivity and TDS Guide for Drinking Water for Livestock and Poultry ........................................................ 23 Bacteriological Analysis Results with Nitrate Concentrations . . . . . . . . . . . . . . . .. 25

LIST OF FIGURES

Relationship between SEC and TDS Piper Diagram: Kalahari Aquifer Wells Piper Diagram: Kalahari Aquifer Project Boreholes Piper Diagram: Kalahari Aquifer Non-Project Boreholes Piper Diagram: Mosolotsane Aquifer Project Boreholes Piper Diagram: Mosolotsane Aquifer Non-Project boreholes Piper Diai,'Tam: Ecca Aquifer Project Boreholes Piper Diagram: Ecca Aquifer Non-Project Boreholes Distribution of Water Types: Kalahari Aquifer Distribution of Water Types: Mosolotsane Aquifer Distribution of TDS Kalahari Aquifer Distribution of TDS Mosolotsane Aquifer Distribution of TDS Ecca Aquifer Piezometric contours: Central Area, Kalahari and Mosolotsane Aquifers Piezometric contours: Project Area~ Eeca Aquifer Hydrochemical Section: Hukuntsi Hydrochemical Section: Hukuntsi to Tshane Hydrochemical Section: Target Area 4 Hydrochemical Section: Target Area 3 to Target Area 2 Variation of SEC with Depth: BH 7872 Variation of SEC with Depth: BH 7874 Variation of SEC with Depth: BH 7889 Variation of SEC with Depth: BH 7918 Piper Diagram: Hydrochemical variation with time, BH 5283, Hukuntsi Hydrochemical Variation with time: BH 5947, Lehututu Hydrochemical Variation with time: BH 5968, Lehututu

APPENDICES

APPENDIX A Analysis Results APPENDIX B Comparison of GRES II and DGS Data

MAP 1 Sample Location Map


LIST OF MAPS

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MATSHENG AREA GROUNDWATER INVESTIGATION Technical Report TB August 1995

1 INTRODUCTION

1

Hydrochemical data collected from archives, and during the Reconnaissance and Drilling Phases of the Matsheng Area Groundwater Investigation have been interpreted, in conjunction with other data sources. The data were interpreted to assess the distribution of water types and variation in chemistry across the Project Area, and with respect to the aquifers penetrated, the main purpose being to identify areas with usable groundwater for livestock production.

The generalised geological sequence for the Project Area is illustrated in Table 1 and is described in detail in Matsheng Area Final Report (WCS, 1995a). Potable water is presently abstracted from the Kalahari Group sediments in the central area, where semi-consolidated sandstones and fractured sandstones or cretes from aquiferous units. The Mosolotsane Formation, where it is more argillaceous, is also utilised. The shallow Kalahari and Mosolotsane aquifers appear however to be very limited in lateral extent (see Section 7, Final Report, WCS, 1995a). The Ecca Group Formations provide moderately high yields throughout the area but the high salinity of the groundwater has prevented their use.

TABLE 1 Generalised Geological Sequence within the Project Area (adapted from Smith. 1984)

Group/Series

Kalahari Group

Lebung Group

Beaufort Series

Ecca Group

Dwyka Series


Formation

Kalahari Group

Mosolotsane Formation

Kwetla Formation

Boritse Formation

Kweneng Formation

Bori Formation

Dukwi Formation

Lithology

Loose sands, cretes, sandstone and mudstone

Mudstone, with sandstone and siltstone

Dominantly siltstone, with subordinate mudstone and minor sandstone

Fine to course, quartz sandstone, coal, carbonaceous mudstone and siltstone

Medium to coarse grained sandstone with subordinate siltstone and mudstone

Siltstone, mudstone and sandstone

Not penetrated

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2

2 DATA

2.1 Data Sources

Existing hydrochemical data was extracted from the Department of Geological Survey (DGS) and Department of Water Affairs (DWA) databases for boreholes within, and adjacent to, the Project area. These data were used to supplement the project data, and were of particular value where samples had been obtained at the time of drilling from boreholes that are now abandoned. In the event that more than one record existed for a particular borehole, the latest dated sample was used, except where this was not considered representative.

During the Reconnaissance Phase of the Project groundwater sampling and wellhead chemical analysis was carried out at all pumping boreholes within the area, also at pumped wells and a limited number of unequipped wells. A total of 39 samples were collected during the Field Reconnaissance Phase: 31 pumped samples, and 8 from hand dug wells by bucket. Additional pumped samples were also collected for analysis for the DGS GRES II Project (GRES 11, in press) and were sent to the Netherlands for anion, cation, and isotope analysis (see Section 2.3).

Further samples were obtained during drilling operations, and from test pumping of Project boreholes. In addition, samples were obtained from boreholes drilled for DWA (supervised by Geoflux) for Lehututu village water supply. Furthermore, several abandoned boreholes in the Lehututu area were visited and sampled by GRES 11 personnel. All the samples obtained for this Project are listed in Appendix A, together with the analytical data. Also listed are the boreholes with archival data, which were used in data interpretation.

2.2 Sampling Procedure

During the Reconnaissance Phase, samples were obtained from existing boreholes and wells by means of pump or bucket. Wherever possible, sampling was carried out after the borehole or well had been abstracting for at least 30 minutes, although this was not possible in all cases.

For Project boreholes, samples were obtained during drilling by air flushing through drill rods. This was generally carried out for between 30 minutes and one hour after striking water, and again on completion of the borehole. If the water sample was still very muddy, or contained foam, flushing was continued until an acceptable sample could be obtained.

Air flushing of boreholes after completion of mud drilling was carried out for longer periods (3 to 6 hours), in order to obtain an acceptable sample.

For each borehole and/or water strike, the following samples were collected: 1 litre sample for analysis at the Department of Geological Survey Chemistry Laboratory

For GRES II Project: Sample for anion analysis Filtered and acidified sample for cation analysis Sample for isotope analysis.

Wellhead analyses were carried out on site by WCS and GRES 11 personnel. This included the recording of: • pH,

• conductivity,

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MATSHENG AREA GROUNDWA'IER INVESTIGATION Technical Report T8 August 1995

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• temperature, • alkalinity (expressed in mg/I as HC03).

A number of wellhead measurements of dissolved oxygen and redox potential were also taken, but the total number was limited due to the late arrival of necessary equipment, equipment malfunctions, and the lack of a Redox electrode or dissolved oxygen meter in the equipment carried by GRES II personnel.

In general there is good agreement between field and laboratory values of SEC and alkalinity. However, field and laboratory pH were not as well correlated, and field values of pH were frequently higher than values obtained from the DGS laboratory. As pH would expected to increase with time, this result is questionable. Due to frequent malfunction of the pH meter used in the field, greater confidence is placed in the laboratory values.

2.3 Analysis of Samples

As part of an inter-laboratory comparison, samples were obtained and submitted to laboratories at both DGS and the Free University of Amsterdam. After comparison of the results from the Reconnaissance Phase (see below), this practice was discontinued mid-way through the drilling programme.

In order to expedite the acquisition of results for interpretation and inclusion in this report, samples obtained during the last two weeks of fieldwork were submitted to the Wellfield Consulting Services Laboratory for analysis.

Comparison of analyses from DGS and Free University laboratories generally showed a good correlation between the two samples sets (Table 2); the data are presented in Appendix B. More detailed comparison of the results will be carried out by GRES II Project. For most ions, the results are well correlated, with a eorrelation coeffieient of greater than 0.95. The exceptions are pH, biearbonate, nitrate and silica. The relatively poor correlation for pH, bicarbonate and nitrate analyses is probably due to the delay in analysing the samples at the Free University, as these parameter would be expeeted to ehange with time.

Generally DGS laboratory analyses have been used in preference to those provided by GRES II Project. The main exception to this is where complete analysis of high conduetivity or discoloured samples were not carried out by the DGS laboratory.

Isotope samples were collected for all Project Boreholes. It has not however been possible to include isotope data in this report due to severe delays in analysis. GRES II Project (GRES II, in press) will report on isotope data in the Lehututu area.

TDS values were not available for all samples, although SEC values were recorded for most. Regression analysis was carried out to determine the form of the relationship between TDS and SEC for samples from boreholes in the Project Area (SEC being the independent and TDS the dependent variable). In this way TDS could be estimated from SEC when values were not available. The results, divided into 3 groups of samples (all data, SEC < 10 OOO/iS/cm, and SEC> 10 000 /is/cm) are shown in Table 3. The plot of SEC against TDS is shown in Figure 1. The high r' value (possible range -1 to 1) shows that SEC and TDS are strongly related, for all values of SEC and TDS. However, the standard error of y values (which indicates how closely the data fits to the regression line projected through it) shows that there is a considerable spread of data for samples with




120000 x

x x

100000 .. ... ,,_ ... ,. <x ................... _ .....

80000 I

} i

60000 ! I

~

Vl X 0 x f- x

40000 t .x

I t " x :

x x

x

I 20000 ...~x , I .

I O~ 0 50000 100000 150000 200000

SEC (uS/cm)

FIGURE 1 Relationship between SEC and TDS


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TABLE 2 Correlation of DGS and GRES II analysis results

Parameter Correlation

.. .. coefficient

pH 0.7273

SEC 0.9969

HCO, 0.7374

Na 0.9970

K 0.9547

Mg 0.9920

Ca 0.9962

Cl 0.9998

SO, 0.9848

NO, 0.8728

SiO, 0.7974

high conductivity (SEC> 10000 !-,S/cm). Therefore, where TDS values were not available, if SEC was less than 10 000 !-,S/cm the following formula was used:

TDS = 0.62 x SEC

For samples with SEC greater than 10 OOO!-,S/cm, the following conversion was used:

TDS = 0.69 x SEC, although due to the high standard error of y described above, for high conductivity waters, the estimated values should be used with caution.

2.4 Spatial Distribution of Data

Prior to the Project, most sample locations were concentrated in the central village area. Due to the absence of fresh, shallow groundwater at any distance from the villages, boreholes were not generally equipped, and water samples could not usually be obtained. The exceptions were BH 5128 at Zutswa (pumped to salt evaporation pans), and boreholes to the east of the villages towards Kang, which were brackish and pumped for livestock watering. Where available, archive data was used; however, frequently such data had incomplete analyses, limiting its usefulness.

Project drilling succeeded in ftlling a number of gaps in sample coverage across the area. Borehole and well locations from which water samples were obtained are shown in Map 1. The Target Area mentioned elsewhere in the text are also delineated on Map 1.

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TABLE 3 Results of Regression Analysis of SEC and TDS

All Data

Constant 0

Std Err of Y Est 5767.489

R Squared 0.951033

No. of Observations 133

Degrees of Freedom 132

X Coefficient(s) 0.689206

Std Err of Coef. 0.011952

SEC <10000

Constant 0


R Squared 0.95396

No of Observations 76


X Coefficient(s) 0.650528

Std Err of Coef. 0.012741 .

SEC >10000

Constant 0


R Squared 0.928594

No of Observations 56


X Coefficient( s) 0.689l42

Std Err of Coef. 0.01845

2.5 Representation of Aquifers

The sample analyses were divided according to the aquifer of origin, the classification being based on the available logs. Many of the existing boreholes had only drillers logs, which were frequently inadequate, and a few were later reclassified based on logs in nearby boreholes. In some cases it was not possible to identify the aquifer, and these samples were assigned to an "unknown/mixed" category. It was assumed that wells only penetrated the Kalahari aquifer.

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In many of the Project boreholes, samples were obtained from more then one water strike, the strikes occurring in different aquifers. If the upper water strike was cased off, or if the yield was minor compared to a lower strike, then the lower strike was assigned to the aquifer the strike occurred in. However, in some boreholes, significant mixing must have occurred and, if the lower sample was considered to be a composite of water from separate aquifers, the sample was placed in the "unknown/mixed" category.

Inevitably, the procedure adopted limited the number of samples that could be assigned exclusively to the Ecca aquifers. In addition, due to the fact that fresh water occurs only in the Kalahari or Lebung aquifers in the Project Area, sample frequency is heavily biased towards the Kalahari aquifer.

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3 GROUNDWATER CHEMISTRY

3.1 Chemical Evolution of Groundwater

The evolution of groundwater, from meteoric water to highly mineralised groundwater, is the result of a number of physical and chemical processes. The chemical composition of groundwater is mainly controlled by solution-precipitation, ion exchange and oxidationreduction reactions. This is further modified by physical mixing, principally driven by pressure, temperature and chemical gradients, diffusion, dispersion, and leakage from adjacent strata.

Total dissolved solids (TDS) and concentrations of most major ions gradually increase in groundwater as it moves along a flow path. Chebotarev (1955) studied analyses of more than 10000 samples of groundwater from Australia. He stated that groundwater chemistry evolves towards the composition of seawater, the evolution tending to be accompanied by a characteristic regional change in dominant anion species:

HCO; - HCO; + SO;- - SO;- + HCO; - SO;- + CI- - CI- + SO;- - cr Domenico (1972) expressed this sequence in terms of three main zones within major sedimentary basins. The upper zone, with active groundwater flushing, has HCO l - type water and low TDS. The intermediate zone, with less active groundwater circulation has higher TDS and frequently has SO; as the dominant anion. The lower zone is characterised by very little groundwater movement, and tends to have high TDS. Water from the lower zone contains highly soluble minerals, as little flushing occurs and high 0-concentrations are characteristic.

The process of evolution is controlled by two factors; mineral solubility and mineral availability along the groundwater flow path. For example, the absence of Cl- in shallow groundwater may be accounted for by a normal lack of chloride minerals along the flow path. If recent groundwater comes into contact with these minerals, water will evolve directly to the Cl- phase, regardless of other minerals present in the system.

The order of encounter is also important (Freeze and Cherry, 1979). As groundwater passes through deposits with different mineralogical compositions, the new mineralogy imposes different thermodynamic constraints, and the water composition is adjusted. Locally, equilibrium may be reached with respect to some mineral phases, but as the groundwater moves through a sequence of mineralogically different strata, further dis-equilibrium occurs. As a result, in areas with complex aquifer systems, groundwater chemistry may exhibit complex spatial distributions that are difficult to interpret, even if good stratigraphic and piezometric data are available.

The Chebotarev sequence implies the existence of a regional groundwater flow system. In the Project Area, where aquifers appear to be vertically and laterally impersistent, the above sequence is unlikely to occur. Individual strata which have different mineralogical assemblages, could result in distinct hydrochemical groups, both vertically and laterally.

Piper diagrams are used to illustrate the major anion and cation distributions of samples from within the Area, and show the groupings of samples into separate water types (Figure 2 a to h). TDS is represented by the size of the circle. The dominant ions determine the water type; ions present in excess of 50% describe the water type.

A straightforward mixture of two water types plots along a straight line joining the two end members. For example, samples plotting along the salt water mixing line indicate a mixture

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8

of Na-Cl and Ca-Mg-HCO, type waters. However, due to water-rock interactions, such as solutiou/precipitation and ion exchange, groundwater frequently deviates from the mixing line. It may evolve from Ca-Mg-HCO, type water, through Ca-Cl" to Na-Cl, or through Na-HCO, to Ca-Mg-HCO, type water. When interpreted in conjunction with piezometric data, such evolutionary sequences may indicate freshening or salinisation trends.

Within the Project Area, Kalahari and Mosolotsane aquifers did not exhibit a particular water type but had groundwaters of various water types. Kwetla and Ecca samples had only Na-Cl type waters. When multiple samples were available from within Kwetla and Ecca aquifers, it was not possible to discern the Chebotarev sequence of decreasing SO; and increasing Cl". This could either be the result of variations in mineral availability, or to the aquifers not being hydraulically connected.

3.2 Kalahari Group Hydrochemistry

Water quality in the Kalahari aquifer within the village quadrangle is generally potable, the samples being predominantly of Ca-Mg-HCO, type and of low conductivity and TDS.

Classification of water based on specific electrical conductivity and TDS is shown in Tablc 4. Samples from the Kalahari are predominantly classified as "fresh", although some brackish and moderately saline samples were obtained from wells. Very saline samples were collected from boreholes at Zutswa, north west Hukuntsi, and Target Area 2. The lack of samples falling into the intermediate category suggests there is little mixing, and indicates a lack of hydraulic conductivity between the highly saline and the fresh Kalahari aquifer.

TABLE 4 Classification of Water Based on Specific Electrical Conductivity and TDS (adapted from Hem. 1978)

Category Conductivity TDS (!'S/cm) (mg/I)

Fresh < 1400 <1000

Brackish 1400 - 4000 1000 - 3000

Mod saline 4000 - 14000 3000 - 10000

Very saline 14000 - 45000 10000 - 35000

Brine > 45000 >35000

pH values are generally in the range 6.64 to 8.21, with only two being greater than 9 (EH 5128 and WCS 80). Alkalinity (as HCO;) tends to be less than 700 mg/l, with CO,- only becoming significant at high pH. It is notable that HCO; and CO; contribute significantly to TDS; high alkalinity (up to 4000 mg/l HCO; + CO;) is frequently associated with increased TDS.

For ease of viewing, the Kalahari aquifer water analyses are plotted on three separate Piper diagrams: wells (Figure 2a), Project boreholes (Figures 2 b), and boreholes other than Project boreholes (Figure 2c). Most of the samples can be allocated to either Ca-MgHCO, or Na-CI water types.

BRlTISH GEOLOGICAL SURVEY Keyworth



~ Cl C :;tl t'j

N '"'"' ~ '-'

>og -. '0 rt> "'l

o -. ~

(JQ "'l ~

53 .. ~ -~ =~ "'l _. ~ -. ;> "'l

~ --'"

Piper Diagram

lOO\. / 100

JU '"" ;80

LL.LJ

Scale of Radli I"' ,00\ Area of

circle 004+Cl Ca+Mg

indicates ~ /40

concentration

in n>g/l 2'\ ;20

0" 0\ / 0 18 4

01~1 o~ 0.9

100_1\ \ 03\>0 9 O'tJ17 _ "X)

0 3 0.3

0 14

80_ _80

oo\~ ~/~ 1-• , f-

~ 4(L _ 40

".!.!)

7 • 16

~ ~ 24

"~19'1~1~~ /

\ _ 20 ..,.!Il,.14 .2 .19 ,9 .4

• ·\tAt •• 6 •• 3 ,}~"5 :15 0_ _0

\100 \80 \80 \40 \20 '0 ; 201

401

601 OO( .00 ;

ca Cl

#- Date Zone Well LD.

DDMMYY

1 120794. 1,3.5 "" 2 120794. 1.3.6 WS

3 1~ 1.3,6 lf34

4 000094 l.ar. lffi9

6 000694 2.4,7 1<69

6 ~ 2.4,7 lf80

7 290794 1.3.6 mlO

6 170B94 2.4,7 lf94

9 00<lIl94 1.3.6 lfOO

10 040694 1,3.5 1<.06

11 000B94 2.4,7 lf114

12 040694 2.4,7 lf116

13 040694 2.4,7 m17

14 000094 1.3.5 1T119

16 000094 2.4,7 1<120

16 00<lIl94 1.3.t> 1<1er.

17 00<lIl94 2.4,7 mea

16 ~ 1.3.5 m36

19 170B94 2.4,7 1<159

~ ~ c:: liQ trl N

----C" '-'

'i:l -. '0 ft> -. o .. ~

IJQ

~ 3 .. ~ -~ ::r ~ -. .. .g c:; ft> -. 'i:l -. 8. ft> ,., ..... 0::1 o -. ft> ::r o -ft> rJ>

JU LLU

Scale of RruUi

Area of

circle

indicateSl

concentr:a.tion

In "'1</1

~/oo 80_

4(L

""-/ • 1

0_ C \100 \80

Piper Diagram

#- Date Zone IT ell LD.

DDMMYY

lOO, / 100 1 04.1194 1.3.t) 7B88

2 051194- 2.a9 7B69

"" /80 3 221194. 2.a9 7B72

_01 "\ 4 231194. 2.a9 7873 ,00\ 5 251194. 1.3.t) 7874

8 281194. 2.a9 7875

Ca+Mg 7 270195 2. ... 7 7832

"'\ /40 B 310195 2. ... 7 7B33

9 16OOge\ 2. ... 7 7B38

"'\ I"" 10 0Bl194. 2. ... 7 7B88

'\ .1 12 07t)i9f; 1.3.5 7B69

13 000!\9!\ 2.a9 79tB

(110 14 ''''''''''' 2. ... 7 7921

1lIS2 0 8 15 1""""" 1.ars. 7923

ol~4 0 2

_oo\~ '> • ~ 0 3 1-

;\ _40

. '" .~ .1.% \ \ \ / I /

• 141720 .10

:'\)"'- c ""~4.1,.6.2

:> _0

\00 \40 \"" \0/ ""I 401

001

801 100 1

Ca Cl

~ Piper Diagram -C':l ~ .# Date Zone Well tD. :;t1

DDMMYY l"l N ,-. t"> '-'

lOO" / 100 1 021188 1.3.5 499 In " 010150 1.4..6 1505 "'t1 e,\ ;80 120001 .. 3 1.3.5 1521 '= LLD ~

4 181283 1.3.5 2B49 ., 0

Scale of Radii 010150 I"' ,00\ 5 2."9 2B27 ..

~ Area of 6 140186 2.4.7 5127 IJQ .,

circle 9J4+Cl Ca.+Mg 7 210694 2.4.7 5128 ~ "'\ 023 ;4{) 8 indicates. CJi 6 <>«JOO4 1.3.5 5283

:;::: concentrat:ion 9 1403B8 2."9 52B4 ~ 2'\ 0 1 /20 - in =g/l 10 300086 1.3.5 52B5 ~ ::r 11 310094 1.3.5 544B ~ .,

0\ oUf)14 12 160093 1.3,5 5B46 ..

>- 020 '(,'\<;6 0 '3

13 030694 2.4.7 5947 ..0 10L = D11 010 14 030694 1.3,5 594B ..

0 '7 ;;> 0 3 gIP 15 141188 1,3.5 5967 .,

80_

1 _80

Z

~/~ 0 5

_00\= 16 310190 1.4.6 5966

0 17 030694 2.4.7 SOW = 0 22 I

"'t1 16 <>«JOO4 2."9 600B ., 0 ..... ~

\ 20 090694 1.3,5 64B4 t"> 4{L ....

t:1:1 , .... ,.~ 21 270295 2.4.7 71155 • 1 0

o .22 22 010395 2."9 7B56 ., 20_ 020 _20 ~ dl'h4 ::r .18 &0 13 23 260695 1.4.,9 7947 0 • ~ 17

~ ~2011~ll~1P12 .. 1~7 .13 - .~ ~ 0_ 022 • .23= __ 0

'" \100 \80 \80 \4{) \20 \0 1 20

1 4{)" SO/ 80/ 100

Ca Cl


9

3.2.1 Na·CI Water Type

Within the overall Na-Cl water type, a further sub-division can be made, based on position on the Piper diagram and TDS. One group of samples have high TDS concentrations (11000 to 13000 mg/l), plotting very close to the NaCl apex; the second group have lower TDS concentrations and plot (generally) along the Na-Cl - Ca-Mg-HCO, mixing line.

The higher TDS water type appears to be characteristic of wells and boreholes adjacent to, or situated on, pans. All the samples are either from shallow water strikes on the edge of active, non.vegetated pans, or deeper water strikes from boreholes located within a few kilometres of active pans. The very high concentrations of Na' and Cl' in these samples indicates that little flushing occurs, as might be expected in this type of closed basin. The higher HCO,"/CO,' content of some samples may, however, be indicative of limited recent recharge, as has been suggested by Butterworth (1982). High sulphate is also a characteristic of this group, and is probably derived from the dissolution of gypsum (CaSO,.2HP) or anhydrite (CaSO,). The former is more likely at temperatures of less than 40°C.

The second Na-Cl type sub-division has lower TDS (up to approximately 7000 mg/l), and, although strictly a Na-Cl-type water, may comprise up to 45% Ca" and Mg'\ and up to 45% HCO,"/CO,·. The samples are all from 5 wells and one borehole, located on Mairi or Hukuntsi Pans in Hukuntsi, or on the south side of Lehututu. The analyses plot approximately along the Na-Cl- Ca-Mg-HCO, mixing line. The reasons for this water type occurring within two distinct areas is not clear, but may be an indication of active recharge, the fresher, recharging waters mixing with higher salinity, Na-Cl type waters.

3.2.2 Ca-Mg-HCO, Water Type

This water type has HCO,' as the dominant anion (generally greater than 60% of total anions), Ca" and Mg" comprising up to 60% and 40% (respectively) of total cations TDS is low, less than 3000 mg/!. This water type may indicate the occurrence of recent recharge (the first stage of groundwater evolution as proposed by Chebotarev (1955), or Zone 1 of Domenico (1972». The dominance of HCO,' as the major anion in recharge areas is due to the rapid dissolution of calcite and dolomite when they are exposed to groundwater with high partial pressure of CO, (Freeze and Cherry, 1979). The following equations illustrate the principle reactions:

cOz + HzD .. HzCO,(carbonic acid)

with CO2 being derived from the air and oxidation of organic matter. Carbonic acid then reacts with carbonate minerals:

This type of water is found in all the villages areas, and indicates the Occurrence of recent recharge. A study of chloride mass balance in the central villages area to estimate recharge was not carried out as this was to be covered by GRES II





10

Project (GRES, in press). Outside the central villages, there were few shallow water strikes, and these were of too high chloride concentration for a study of chloride mass balance to be meaningful.

3.2.3 Na-HCO, Water Type

The occurrence of Na-HCO, type waters may be explained by a combination of carbonate dissolution and cation exchange, with high NaHCO, waters being produced in sediments which have both significant amounts of carbonate, and clay minerals with exchangeable Na' (Freeze and Cherry, 1979). Beekman and Selaolo (1994) identified this type of water in the Lethlakeng-Botlhapatlou area, and concluded that the waters had evolved from Ca-Mg-HCO, type waters, with Na' being replaced by Ca" and Mg" on the exchange sites of clayey sediments. The water type thus represents the modification of Ca-Mg-HCO, type water by groundwater flushing.

In the Matsheng area, the water type has been identified on the southern edge of Lehututu, in Hukuntsi, and in boreholes drilled along the Lokgwabe/Tshane Road and to the east of Lokgwabe.

3.2.4 Ca-Cl, Water Type

Several boreholes interpreted to have a Kalahari water strike yielded this type water, all were located to the northwest of Lehututu. This type of water may be attributed to the effects of saline intrusion, possibly due to the effects of overpumping (Beekman, pers. comm), and is discussed further in Section 3.5.1.

3.3 Mosolotsane Formation Hydrochemistry

Samples from the Mosolotsane Formation are predominantly of Na-Cl type, with TDS concentrations up to approximately 100000 mg/1. The samples are plotted in Figures 2 d and e. pH ranges between 6.88 and 8.91, HCO,' / CO; vary between 645 and approximately 1500 mg/1. Based on the data available, there does not appear to be a strong correlation between SEC and HCO,', indicating the TDS is not as dependant on alkalinity as is the case for the Kalahari aquifer. Within the Na-Cl water type, three subdivisions may be defined. The first subdivision consists of analyses concentrated near the NaCI apex; these have the highest TDS. The sample from BH 6327 (Monong) is unusual within the subdivision, having approximately 50% SO; (of total anions). The remainder are less than 35% SO;.

The second subdivision has higher HCO; (up to 60%) tending towards Na-HCO, type water, with slightly lower TDS (less than 2000 mg/I), and may represent some slight refreshing of saline water by recharge. Boreholes with water of this type are located predominantly at Hunhukwe, although others are BHs Z7350 and 7892 east of Lehututu. The third group has higher Ca" and Mg", tending towards Ca-Cl, type water, and is represented by three boreholes in the north east of the Project Area (Target Area 3 and Target Area 4).

The remainder of the samples are of Ca-Mg-HCO, type, and plot very close to the Na-Cl _ Ca-Mg-HCO, mixing line, all having relatively low TDS.

Overall, the samples plot in similar positions to those described for the Kalahari aquifer.

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11

3.4 Ecca Series Hydrochemistry

In several boreholes, water strikes occurred towards the base of the Kwetla Formation, with yields generally increasing significantly on penetrating the underlying Boritse. Although the first water was actually in the Kwetla, and the water chemistry may have been modified by Kwetla mineralogy, the Kwetla itself is not an aquiferous horizon. The aquifer is positioned within the upper part of the Boritse Formation, and will be referred to as such.

All samples from Ecca aquifers plot in similar positions on the Piper diagram (Figures 2 f and g), and are grouped together for the purpose of discussion. All samples are of Na-CI type, and are moderately saline to brine (TDS ranging from 7000 to 35000 mg/I. The only exception is BH 7927 at Monong, which struck slightly better quality water (TDS 4800 mg/I) at 389m at the top of the Boritse Formation, although the SEC increased slightly to 6200 mg/I (laboratory analysis) by the end of drilling (30m into the Boritse). It should be noted that many more nearby boreholes, for which no conductivity values are available, were noted on the borehole completion certificate as being saline or very saline. Most of these boreholes were never equipped and have been abandoned. The temporal decline in water quality observed in nearby boreholes is discussed further in Section 5.

The range of pH values is similar to those measured in the Kalahari, being 7 to 8.2. Alkalinity values are lower than for the Kalahari and Mosolotsane groundwaters, being within the 66 to 610 mg/I (as HCO;) range. Unlike Kalahari waters, high conductivity values were not associated with high alkalinities, indicating there was little contribution to SEC from HCO; and CO; anions.

TDS is high, greater than 10000 mg/l, with the exception of BHs 7927 at Monong (TDS of 6200 mg/l on completion of the borehole) and 7831 (TDS of 7480 mg/l). Sulphate values are generally greater than 20% and up to 55% of the total anions. The source of sulphate within the Ecea deposits could possibly be from the oxidation of pyrite, which was observed in chip samples in several boreholes. In BH 7829, a sulphurous odour was detected at a depth of approximately 360m. The water sample for this borehole had only 20% SO; which, together with the presence of hydrogen sulphide, indicates the very low redox potential of the groundwater (Freeze and Cherry, 1979).

Due to the mixing of samples during the drilling process, no samples were available specifically from the Kweneng aquifer, although comparison of final samples and those from the Boritse in the deep boreholes indicates no major change in water quality. Similarly, bore hole geophysical logging does not indicate a major change in water conductivity between Boritse and Kweneng Formation groundwaters.

3.5 Spatial Distribution of Water Types

The distribution of water types and TDS for each aquifer is shown in Figures 3 (a and b) and 4 (a, b and c) respectively. As all Ecca groundwaters were NaCl type; these have not been plotted, and therefore only Kalahari and Mosolotsane samples are illustrated in Figure 3. Across the Project Area, relatively shallow water strikes occur either in the Kalahari or Mosolotsane Formations, but they do not occur in both.


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MATSHENG AREA GROUNOWATER INVESTIGATION

TB 10/2/12/92-93

HYDRO CHEMISTRY OF THE MATSHENG AREA

Technical Report T8

Figure 3(a)

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TB 1 O/2/12/92~93


T echnica! Report TB

Figure 3(b) I Distribution of Water 'I

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TB 10/2/12/92-93


Technical Report T8

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TB 10/2/12/92-93


Technical Report T8

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12

3.5.1 Kalahari Formation

Village Areas

Within individual villages, groundwater is dominantly low TDS, and of Ca-MgHCO, type. This type of water indicates recharge and based on its distribution, possible recharge areas have been delineated on Figure 3(a).

There are some Na-HCO, type waters, although these still have quite high proportions of Ca" and Mg" ions, indicating that the water has been transported from the recharge area, and the composition partly modified by ion exchange. The boreholes are generally located on the edge of the villages and also along the Tshane-Lokgwabe road. Contours of the piezometric surface for the central area (Figure 5a) indicate the hydraulic gradient generally slopes from northwest to southeast, suggesting the recharge area for the latter boreholes would be Hukuntsi. However, evidence from drilling indicates there is no hydraulic connection between the two areas. Presently there not sufficient data to explain the distribution.

Within Hukuntsi village, there is an overall change (approximately down hydraulic gradient) from Ca-Mg-HCO, type waters to Na-HCO, and Na-Cl types from north to south, the Na-CI higher TDS types being from wells on Mairi or Hukuntsi pans (see Figure 6). Several boreholes drilled to the northwest of Hukuntsi Pan had deeper, Mosolotsanc water strikes, and proved to be saline, with recorded TDS of up to 100 000 mg/1. One possibility is that there is some upward leakage of saline, Mosolotsane water from the boreholes to the west. However, borehole logs for the area are inadequate to gain an understanding of the situation. Alternatively, and possibly more likely, the increased salinity may be derived from the pans themselves.

Ca-Cl, type water occurs in the Kalahari, to the northwest of Lehututu. Two boreholes (1505 and 5968) were both backfilled and cemented from the original drilled depth, possibly indicating the occurrence of more saline water at depth. If a saline water strike is interpreted, the depth at which this saline water may be encountered is not clear as Bh 499, within a few hundred metres of BH 1505, was drilled to greater depth and does not have Ca-CI,-type water.

As described above, the hydraulic gradient within the village quadrangle is generally northwest to southeast with the aquifer being slightly confined. The opportunity to examine chemical evolution of groundwater along the hydraulic gradient in the Kalahari aquifer, was limited by the spatial distribution of boreholes, the limited lateral extent of the shallow aquifers, and the apparent isolation of the aquifers being penetrated. Numerous hydrochemical traverses were examined within individual villages but with the exception of the traverse across Hukuntsi described above, did not indicate any evolution of groundwater down hydraulic gradient. One hydrochemical traverse was run along the HukuntsiTshane road, approximately down hydraulic gradient, utilising data from BHs 5846, 7868, 6484, and Z5596 (west to east) (Figure 7) There does not appear to be any coherent pattern of groundwater evolution along this traverse. All samples are CaMg-HCO, type water, with BHs 5846 and Z5596 having slightly a higher proportion of Cl' than the other samples. The lack of any evolutionary trend supports the suggestion that there is no hydraulic connection between the villages, although it is also possible that the distance is too short to allow major changes in chemistry to evolve.


WELLFIELD CONSULTING SERVICES P,Q,Box 1502

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TB 10/2/12/92-93


Technical Report T8

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Figure 5(b) I Ecca Aquifer 11

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13

Project Area Periphery

Outside the village quadrangle area, Kalahari groundwater is invariably Na-Cl type, with high TDS and conductivity. Other than in Target Area 2 (TA2), water strikes occurred only On the edge of pans. Samples from the Kalahari Group in Target Area 2 were obtained from greater depth than other Kalahari samples. The samples from BHs 7832 (lkm south of Matshaneng Pan) and 7836 (on the edge of the pan) were both highly saline (TDS of 115300 and 100000 mg/l respectively). BH 7833 was located 5km south of the pan, on the opposite side of a lineament identified by geophysical surveys. This borehole had a Kalahari water strike 19m above that in BH 7832, and had water of much lower salinity: TDS was 36000 mg/I. The role of the lineament between boreholes 7832 and 7833 is not clear; it seems unlikely to have any control over the water chemistry and does not explain the considerable difference in Kalahari water samples between the two boreholes. An explanation for the very saline water in BH 7832 could be that it is located at the site of an ancient pan; possibly an extension of the present day Matshaneng Pan. Evidence for pan migration has been put forward for other areas (e.g. Butterworth, 1982), and cannot be discounted in this area. BH 7833 may be located towards the edge of the ancient pan, the water quality being modified by recharge, as has been suggested by Butterworth.

3.5.1 Mosolotsane Formation

Village Areas

Mosolotsane waters within the villages are generally low TDS, Ca-Mg-HCO, type. On the western edge of Hukuntsi, high TDS (up to 100000 mg/l), Na-CI type waters were encountered; these are the only very high TDS Mosolotsane waters within the central villages area. It is possible that upward leakage from this aquifer is responsible for the poorer quality water in the adjacent Kalahari aquifer. This has been discussed in Section 3.5.1.

Project Area Periphery

Outside of the central village quadrangle, the Mosolotsane aquifer accounts for most of the relatively shallow water strikes not associated with pans. Similar to the Kalahari, the waters are relatively high TDS (up to 50000 mg/l) and of Na-Cl type, although lower TDS is encountered to the east of Lehututu and in the Hunkukwe area.

The Mosolotsane aquifer to the east of Lehututu (Target Area 4) has rather better quality water. Although not generally considered potable, water of usable quality for livestock (generally up 50 000 mg/l TDS, 6000 ,"S / cm SEC) extends along the line of the Kang Road to the ENE. The extent of the fresher water appears to be limited; as shown in Figure 4b, water of less than 3000 mg/l TDS (i.e. brackish) was only recorded in BHs 7892 and Z7350 (approximately 400m apart), and the remaining boreholes in the area are classed as saline.

With the exception of these two boreholes (Na-HCO, type water), samples within Target Area 4 are Na-Cl type. The relatively high proportion of Ca'· and Mg'in the west diminishes eastwards as the rest of the ions increase (Figure 8). TDS varies between 8000 mg/l in the east to 27000 mg/l in the west decreasing to 1600

BRITISH GEOLOGICAL SURVEY KeYWOrth



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14

mg/l at BH 7892. The overall increase is towards the east, in the same direction as the apparent hydraulic gradient.

The source of the fresher water remains unclear, despite extensive investigations in Target Area 4. Re-examination of air photos and geophysical investigations were carried out, but did not provide any useful information. A major lineament delineated by remote sensing, (the "Tshane Lineament, see Technical Report 1'2 (WCS, 1995b» follows a southwest to northeast trend, with all the villages located to the northwest.

Relatively fresh water in BHs 7892 and Z7750, and the results of the Botanical Survey, which showed there were no indicators of shallow groundwater to the south east of the lineament (Technical Report T2, WCS 1995 b), initially suggested that this feature might be associated with fresher water to the north. However, further boreholes to the northwest of the lineament (7893 and 7925), have yielded saline water. Furthermore, there has been no evidence from drilling to suggest the lineament is of a geological origin, and it now seems probable that it is related to grazing and/or vegetation patterns.

3.5.3 Ecca Group

All Ecca Group waters were of Na-CI type, with varying, but high, TDS (up to 35000 mg/l). The variation of salinity, and of the relative proportions of anions, across the Project Area is not systematic, and is probably a localised function of mineral availability.

It was not possible to interpret the accurate hydraulic gradient in deeper aquifers because of the paucity of elevation and precise piezometric data for individual Ecca Formations (see Section 7.4, Final Report, WCS 1995a). Water levels differ by several tens of metres over a few kilometres, although the piezometric surface generally showed a decline from northwest to southeast (Figure Sb). Chemistry data for two traverses across the area were plotted from Monong in the northwest to TAl and from TA3 to TA2 (north-south) (both generally down hydraulic gradient). There is no indication of an evolutionary trend along the long traverse from northwest to southeast. However, the north-south traverse shows an overall increase in TDS, caused by increasing Na' and cr, combined with a decrease in SO; (Figure 9). This could indicate evolution of groundwater from north to south, as described by the Cheboratev sequence. Although the water levels vary by approximately SOm, the deep water strike levels were within 20m, with the water strikes all being towards the base of the Kwetla/top of Boritse Formations. The boreholes are thus possibly all penetrating the same, laterally continuous aquifer. However, with multiple water strikes in all but one of the boreholes, it is not possible to obtain the necessary accurate piezometric data for individual aquifer units in order to determine groundwater flow direction, and therefore confirm the apparent flow path.

3.6 Hydrocbemical variation with depth

Within localised areas, and even within the same borehole, Kalahari or Mosolotsane waters are frequently more saline than those of deeper Ecca Group aquifers. However, variations within each Group or Formation are very much more limited.

BRmSH GEOLOGICAL SURVEY Keyworth



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FIGURE 9 Hydrochemical Section: Target Area 3 to Target Area 2


15

3.6.1 Variation of Conductivity with depth: Kalahari/Mosolotsane Formations

Conductivity variation was monitored as drilling progressed in several boreholes. The logs are shown in Figure 10 (a,b,c and d) for BHs 7872, 7874, 7889, and 7918 respectively.

BH 7872 (Figure lOa)

The conductivity log is erratic, and of limited use. Overall, there is an increase in conductivity with depth, although the conductivity appears to stabilise after the Kalahari/Mosolotsane boundary.

BH 7874 (Figure lOb)

Conductivity increases steadily with depth from 38m to the base, the log following virtually a straight line from the level of the mudstone (Kalahari/Mosolotsane boundary) at 45m to the base at 60m.

BH 7889 (Figure 10c)

The log shows a gradual increase in conductivity from 1125IlS/cm (TDS approximately 731 mg/l) at 18.5m to 1184IlS/cm (TDS approximately 770 mg/l) at the base of the borehole (64m), coincident with a steadily increasing yield from 10m3/hour at 28m to 17m3/hour at 64m.

BH 7918 (Figure 10d)

There is an overall increase in conductivity between 40 and 60m (the Kalahari/Mosolotsane boundary being at 55m), the readings then remaining fairly constant almost to the base.

Overall, there is an increase in conductivity with depth, the increase continuing after penetrating Mosolotsane mudstones, although it does appear to stabilise in BHs 7872 and 7918 within a few metres of the Kalahari/Mosolotsane contact. The difference is difficult to interpret; there is some evidence of increased salinity of water within the Mosolotsane from boreholes 7889 and 7874, but not in BHs 7872 or 7918. If higher salinity water does exist within the mudstones of the Mosolotsane Formation, it would probably seep only slowly into the borehole after drilling. It therefore would not be expected to significantly affect conductivity readings taken during drilling, unless there are coarser horizons within the mudstone sequence which are capable of transmitting water more rapidly. This could be the case in BH 7889 which was reported to have a siltstone horizon towards the base of the hole.

3.6.2 Variation of Chemistry with Depth: Deep boreholes

Multiple samples were collected where possible from the deep boreholes, sampling being restricted in the case of the mud-drilled boreholes because of the method of drilling. In these boreholes, conductivity measurements were recorded at regular intervals. However, because of mud loss into the formations, the conductivities were dominated by the conductivity of the water used in drilling, and little information about formation water conductivity could be deduced. For some




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16

of the boreholes, the variation of water quality with depth in the deeper aquifers has been partly revealed by borehole geophysical logging.


BH 7832

Two samples were obtained from Kalahari Group and top of Boritse Formation water strikes. Drilling continued to 531m, with a possible further water strike at 409m in the Kweneng Formation this could not be sampled due to the use of mud drilling techniques, but a sample was obtained after flushing the borehole on termination. Although cased off, there was the sound of cascading water in both this and BH 7833 after completion, and there is a possibility that Kalahari water was entering the boreholes and mixing with Ecca water.

The decrease in TDS (from 115300 to 27000 mg/I) combined with an increase in SO; between Kalahari and Boritse water strikes is in opposition to the evolutionary sequence that would be expected if the aquifers were hydraulically connected, confirming the lack of connection between the Kalahari and Ecca aquifers. In the deeper aquifers, there is a slight decrease in TDS (27000 to 22500 mg/I) between the water strike at 248m and the final sample from 531m. There is also a very significant decrease in SO,·, from 7738.8 mg/I at 248m to 61.7 mg/I at final depth. Although this is possible evidence for slightly fresher water in the Kweneng aquifer, the conductivity values from geophysical logging do not give any indication of fresher water at depth, with a fairly consistent conductivity of approximately 65000)1S / cm (TDS approximately 45 000 mg/I being recorded from the rest water level to the base of the borehole. This, in itself, indicates some leakage from the Kalahari has occurred since completion of drilling. As the Kalahari water strike was at 70m, and the static water level is now just over lOOm, this seems quite likely.

BH 7833

Two samples were collected from Kalahari (51m) and Boritse (268m) water strikes. There is little difference between the two samples. Both have TDS around 35000 mg/l and conductivity 48000)1S / cm, indicating that some leakage past the casing, and therefore mixing of samples, may have occurred before the lower sample was obtained. The conductivity log from downhole logging indicates that from 77 m to the base conductivity is approximately 30000 )1S/cm (TDS approximately 21 000 mg/I) with little variation with depth.

BH 7837

Two samples were obtained from 77m (Mosolotsane Formation) and from 128 m after penetrating the Kwetla Formation (although no actual water strike was identified within this formation). The two analyses are virtually identical. Geophysical logging indicates fairly constant conductivity to approximately 229m, where it decreases from approximately 20000 to 15000)1S/cm (TDS from 14000 to 10000 mg/I, approximately). The decrease could possibly indicate a slightly fresher, lower water strike, although none was recorded during drilling.


MATSHENG AREA GROUNDWATER INVESTIGATION Technical Report 1"8 August 1995

17

BRlTISH GEOLOGICAL SURVEY Keyworth ,Nottingham, UK

BH 7838

Two samples were obtained, one at the water strike at 261m (Kwetla Formation) and one from the final depth (480m) after penetrating a thick dolerite sill beneath Boritse Formation sandstones. Again the samples are virtually identical, being Na-CJ type, with TDS approximately 13000 mg/l and conductivity 18700"S/cm. No water strikes were detected after 261m. Conductivity from geophysical logging is reasonably constant, between 15000 and 20000"S/cm (10 000 to 14000 mg/l TDS approximately), to 360m where there is a small decrease to 12000 to 13000 "S/cm (TDS approximately 8500 mg/l), a further decrease occurs at 470m, where conductivity reduces to approximately 7ooo"S / cm (TDS approximately 5000 mg/I. The upper decrease may indicate a water strike, being within an alternating sandstone and coal sequence in the Boritse Formation or it may be a reflection of the changing lithology. The reason for the lower change is not known; it is not likely to represent a water strike as it is well within a thick gabbro/ dolerite, and is probably a function of logging, being close to the base of the borehole.

BH 7829

Two samples were obtained from 274m (Boritse) and from the final depth (517m), in the Bori Formation. There is a slight increase in TDS with depth from 22700 to 24700 mg/l (SEC 28400 to 32400 "S/cm). There is little difference between the samples, except for a decrease in the relative proportion of SO,' from approximately 40% to 20%. Considering also the increase in TDS, this indicates possible evolution between the two water types, although the existence and depth of the possible second aquifer is unknown as no further water strike was detected during mud drilling.

BH 7880

Three samples were obtained from 93m (Mosolotsane), 385m (Boritse), and fmal depth (492m) in the Boritse Formation. Both Mosolotsane and Boritse samples plot in almost identical locations on the Piper diagram, with a slight decrease in TDS between the two (36000 to 35200 mg/l). Again the similarity of the samples seems suspicious, and may indicate leakage outside the casing from the Mosolotsane aquifer, and contamination of the lower (Ecca Group) water samples.

BH7885

Three samples were obtained from 225m (Kwetla), 395m (Boritse) and from final depth (700m) in the Bori Formation. All samples have similar TDS and conductivity (15000 mg/l and 23000 "S/cm respectively) and plot in similar positions on the Piper diagram. The sample obtained from 225 m was seepage and is therefore unlikely to have a significant effect on samples obtained from the Boritse and Bori formations. It therefore appears that, at least at this location, Kwetla and Boritse groundwaters are of similar composition.



4 HYDROCHEMICAL CHANGES DURING TEST PUMPING

18

Four boreholes were test pumped; three in the Lokgwabe area, and one in Target Area 4: EHs 7872, 7889, 79231 and 7892. Samples were obtained at the end of the fIrst and last step, and after 24 and 48 hours of the constant rate test. TDS was also recorded regularly through the tests to monitor any major changes in salinity, none were observed. .

None of the boreholes showed major systematic variation during pumping, either in the wellhead chemistry results or in the laboratory analyses. The results are shown in Table 5.

I Samples from EH 7923 were stolen

BRTTISH GEOLOGICAL SURVEY Keyworth Nottingham, UK


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20

5 TEMPORAL CHANGES IN HYDROCHEMISTRY

Using archive data, it was possible to trace cbanges in hydrochemistry with time at several of the boreholes in the Project Area. The major problem with this type of exercise is that the exact source of the samples is unknown; for example, several boreholes have more than one set of results for the same date, but no record of why more than one sample was taken. In the case of samples obtained during drilling, they could represent different water strikes. Where sufficient records existed, samples could be linked to drilling or test pumping; however, this was frequently not possible. A second problem, specifically associated with BH 6339 at Monong, was that some samples had been obtained after desallnation.

BH 473: Tshane

The public supply borehole at Tshane does not have water quality records older than May 1988; 8 results were available for the period between May 1988 and July 1994. The major ions and conductivity fluctuate, but there is no clear hydrochemical trend over this period.

BH 5283: Hukuntsi

8 samples were available between completion of drilling in February 1986 and Project sampling in August 1994. The samples from the end of drilling and the pump test show a change in water type from Na-Cl to an intermediate water type, more dominated by HCO; (Figure 11). The anion triangle clearly shows the decrease in Cl- and concomitant increase in HCO;. This suggests that, with time and pumping, water quality has improved, implying that fresher water is being drawn into the area, either from depth or laterally. Nitrates fluctuate but show a slight upward trend, tending to support the latter, the source of nitrates being more likely to be near surface. However, they could also be increasing simply due to increased input of nitrates from the cattle on the pan.

BH 4516: Hukuntsi

Six samples were available from April 1988 to August 1994. There is a slight increase in conductivity, but no major upward or downward change in major ions.

BH 5448: Lokgwabe

Five samples were taken between December 1986 and July 1994. TDS and conductivity vary little. There was a decrease in sulphate and chloride from between 1986 and 1991, but little change since. There has also been a slight, but gradual increase in HC03', possibly indicating recharging water being drawn into the area; this would also help explain the decrease in SO; and Cl'.

BH 5947: Lehututu

8 samples were available for BH 5947. However, the first two samples were dated prior to the start of drilling in September 1988, and must therefore be assumed to be wrongly attributed. The water is of an intermediate type, most of the samples plotting quite close to the Ca-Mg-HC03 - Na-CI mixing line; the Piper diagram indicates a slight change towards more strongly Na-Cl type between the end of drilling (24/9/1988) and the rest of the samples. There is an overall increase in TDS between 1988 and 1994 (from 748 to 1148 mg/I), possibly indicating some degree of saline intrusion. The hydrochemical change with time is shown in Figure 12. The high TDS recorded in October 1992 appears to coincide with an increase in abstraction from the borehole (data from Council records) from




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FIGURE 12 Hydrochemical Variation with Time: BH 5947, Lehututu


21

approximately 1500 m' /month to nearly 2500 m' /month, again indicating saline intrusion may occur, particularly at high discharge rates.

BH 5968: Lehututu

BH 5968, penetrating the Kalahari Aquifer, has already been discussed in Section 3.5 in reference to its Ca-Cl, water type. Four samples were available between July 1988 and January 1990 when the hole was pump tested. There is a marked increase in TDS Na+ and Cl' concentrations between 1988 and 1990, accompanied by mOre modest increases in other ions (Figure 13). The exceptions were P- and NO;, both of which decrease, the reduction in nitrate being significant (245 to 39 mg/I). This adds weight to the theory that underlying saline water is intruding the upper fresher water aquifer. The borehole was never equipped, although whether this was due to salinity or low yield could not be determined from local enquiry or the completion certificate. It is possible that the pumping test was carried out in order to determine yield in preparation for equipping the hole, but that the rapid decrease in water quality on pumping rendered the water unusable.

BH 6339: Monong

7 samples were available for BH 6639; however, many are incomplete, only conductivity being recorded for all samples. A wide range of TDS values are recorded, from approximately 25000 mg/I during drilling to less than 10000 mg/1. The recent borehole (7646) drilled adjacent to BH6339 had a recorded conductivity of 23000 /-is/cm (TDS approximately 15870 mg/I). This could be an indication of deteriorating water quality, but there is no long term trend discernible in the conductivity fluctuations.

Overall, there is little indication of deterioration of water quality with pumping in the Project Area, the exception being BH 5968, north of Lehututu. This area requires further, careful, investigation to determine the source of the saline water, particularly as three production holes have recently been drilled in the vicinity.


WELLFlELD CONSULTING SERVICES P.O.Box 1502 Gaborone, Botswana

FIGURE 13

BB 5968

Date

____ Conductivity -0-- HC03

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- "'- Ca

Hydrochemical Variation with Time: BH 5968, Lehututu


22

6 GROUNDWATER WATER QUALITY AND USAGE

6.1 Drinking Water Standards

Drinking water, for humans or animals, should be of certain chemical, physical, and bacteriological quality. A variety of standards exist; some of these are given in Table 6, including the standards that are utilised within Botswana. Few references are available giving standards for livestock water, but most animals are able to tolerate much higher TDS concentrations than humans. Cattle in the United States, for example, have been observed to become accustomed to drinking highly mineralised water, up to 10000 mg/l TDS (Hem, 1978). TDS limits given in Hem (quoted from McKee and Wolf, 1963) are: cattle (beef), 10,100 mg/l; sheep, 12900 mg/l; horses, 6435 mg/l. Table 7 presents a guide for conductivity limits for drinking water for livestock and poultry. At high TDS the actual ionic components become important. Peirce (1957) suggested that divalent ions (Ca2+, Mg", SO; and HCO;) may be more toxic than monovalent ions (Na' and Cl"). Hem (1978) also reports that livestock are less able to tolerate high SO; than high Cl' concentrations in groundwater.

Also important with regard to high TDS waters, is the amount of water consumed by the livestock, which in turn is related to humidity and temperature, nature of feed, and exertion (Steyn and Reinach, 1939). The same authors report that, although a tolcrance may develop to high TDS waters, poor growth, and decreased productivity and reproduction become apparent in the long term.

Within the Project Area, cattle were observed to be drinking water of up to 36000 mg/l TDS (BH Z7258), but it is not known how long the cattle continued to drink this water, or if they survived. In other parts of the Project Area, boreholes were drilled and equipped (BHs Z4561 and Z5316), and animals drank the water, but later died. The latter borehole, to the south west of the area, was reported to have been used for 6 months before livestock mortality stopped its use.

Limits of 100 mg/l nitrate and nitrite (as N) have been quoted for livestock consumption (National Academy Sciences and National Academy of Engineering 1972); this is approximately double the limits for nitrates in drinking water for humans.

6.2 Groundwater Quality in the Matsheng Area

The major limiting factor regarding groundwater usage in the Matsheng area is the high TDS of the water, rendering it largely unsuitable outside of the central villages, even for livestock. There are exceptions, i.e. TA 4 and Monong (TDS 5000 to 6000mg/l, which have yielded water suitable for livcstock watering, although the sustainability of the relatively fresh water at Monong is doubtful. Outside the village quadrangle, nitrates are low and do not constitute a problem. Fluoride is generally within drinking water limits throughout the area.

Many of the Kalahari and Mosolotsane wells and boreholes within the village areas are above the nitrate limits set in the standards above; some of them significantly so. Many are also above the limit of 100 mg/l for animal consumption. It is notable that most of the public supply boreholes are above the limit, BH 473 at Tshane being the worst with NO, of 138mg/1. Within the villages, generally it is the boreholes and wells closest to the village centre that have the highest levels. Lokgwabe has the lowest nitrate levels of the group of villages; however, these are still just over the 45 mg/l standard.





23

TABLE 6 Water Quality Standards: Drinking Water for Human Consumption

USEPA EEC (1975) Botswana (National (1975) (Maximum Water Master Plan)

'. (Recommended limit) admissible (Maximum concentration) permissible

. .

. . . ' . . ... . concentration) .

pH 9.5 6.5 - 9.2

TDS (mg/I) 500 1500 1500

er (mg/I) 250 250 600

SO; (mg/I) 250 200 400

NO; (mg/I) 50 50 45

F (mg/I) 1.4 - 2.4 1.4 - 2.4 1

Na' (mg/I) 100

E. Coli /100ml 0 0

T Coli /100ml 1 0 10

TABLE 7 Electrical Conductivity and TDS Guide for Drinking Water for Livestock and Poultry (adapted from National Academy of Sciences and National Academy of Engineering. 1972)

.. TDS (mg/I) SEC (!1S/cm) Comment

< 1000 < 1500 Excellent for all classes of livestock and poultry

1000 - 3000 1500 - 5000 Very satisfactory for all classes of livestock and poultry. May cause temporary diarrhoea in

livestock not accustomed to it

3000 - 5000 5000 - 8000 Satisfactory for livestock; may cause temporary diarrhoea or be refused at first by animals not

accustomed to it. Poor water for poultry

5000 - 7000 8000 . 11000 Can be used with reasonable safety for dairy and beef cattle, sheep, swine and horses. Not for

pregnant or lactating animals. Not acceptable for poultry.

7000 - 10000 11000 - 16000 Considerable risk for pregnant or lactating cows, horses or sheep, or for the young of these. Older ruminants, horses and swine may subsist on water

under certain conditions. Unfit for poultry.

> 10000 >16000 Cannot be recommended for use under any conditions: very high risk

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24

As would be expected, high nitrate concentrations were not detected in samples from Ecca aquifers.

As nitrogen based fertilisers are not widely used in the area, the source is likely to be from animal or human waste. The high nitrate concentrations in wells located on pans is probably from animal waste washed from the surface into unprotected open wells. However, many of the high concentrations occur in boreholes and wells within the village areas, suggesting a major source of nitrate is from pit latrines.

Microbiological analyses were also carried out for all pumping boreholes and some wells in the central village areas. Coliform bacteria live in the intestinal tracts of warm-blooded animals, and have long been established as a criterion of the degree of pollution. Although non-pathogenic in themselves, they are an indicator of faecal pollution.

Analysis of borehole and well samples in the village quadrangle indicated the presence of coliform bacteria in several of the samples; the results are summarised in Table 8. Repeat analyses were carried out if there was any doubt regarding the initial results.

Three water points consistently had high counts of both E. coli and total coliforms. These were WCS1l4 in Lehututu, WCS56 at the Hukuntsi Trading Store, and BH7884 at Lokgwabe. The sample from WCS1l4 also had a high nitrate concentration (212 mg/l), a further indication of contamination. As the well is used only for livestock watering, the contamination is not a serious concern. WCS56 is, however, a drinking water supply. It is not clear whether the contamination is derived from livestock or human waste as the well is located in the back yard of a dwelling, close to Mairi Pan. The nearest potential source of contamination is, however, likely to be the dwelling's septic tank/soakaway. The results from BH 7884 are surprising, as nitrates are relatively low (58.3 mg/l as N). It should be noted that it was not possible to obtain the sample directly from the wellhead at this borehole, but it was necessary to collect the sample from the nearby reservoir, possibly introducing contamination. The pit latrines, dug directly into the calerete outcrop at the Primary School opposite the borehole, should also be recognised as a potential source of groundwater pollution, although the low nitrate concentrations indicate these are not at the present time causing serious groundwater contamination in the area.





TABLE 8 Bacteriological Analysis Results with Nitrate Concentrations

EH E Coli Total NO; (as N) Number (/100 ml) Coliforms (mg/I)

. (/100 ml) .

W 56 3000 25000 2000 19000

W 114 6000 9000 212.0 1000 4000

473 2000 6000 138.4 0 0

4516 1000 1000 93.9 0 0

4617 1000 4000 117.0 0 0

5283 0 0 57.2

5448 0 0 43.6 0 0

5947 2000 0 73.9 0 0

5948 0 5000 71.7 0 0

6046 0 0 58.9

6088 0 0 80.6

6482 0 0 89.8 0 0

6484 0 1000 88.5 0 0

7884 5000 39000 58.3 4000 43000

Note: 1. Duplicate samples were obtained for most boreholes. 2. BH 7884 was sampled from the storage tank outlet.

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25


7 DISCUSSION

26

The Kalahari and Mosolotsane aquifers are the only sources of potable water within the Project Area, other than rainwater. Even in these aquifers, water quality outside the Matsheng villages is generally poor. In fact, Kalahari and Mosolotsane waters were frequently of higher conductivity than waters from the Ecca aquifers. The only water strikes in the Kalahari Group outside the central villages occurred adjacent to, or in close proximity to, pans. However, the water was almost invariably highly saline and, with the sole exception of Phepane Pan, not of sufficiently low TDS to be usable for cattle. The distribution of known usable groundwater in the Project Area is illustrated in Figure 9.1 of the Final Report (WCS, 1995a).

Within the villages, water quality is generally good and dominantly of Ca-Mg-HCO, type, indicating recent recharge has occurred. There is no evidence from drilling or hydrochemical trends, of a lateral connection between the shallow aquifers known to exist in the immediate vicinity of individual villages, although piezometric contours indicate a general northwest to southeast hydraulic gradient in the Kalahari Group across the village area.

At present, water quality does not appear to be deteriorating markedly. There is, however, a potential problem from nitrate and bacterial contamination of these aquifers. Whether the source of contamination is human Or livestock, the situation is not likely to improve in the future.

There appears to be no general agreement as to the formation of the Ca-CI,-type waters encountered to the northwest of Lehututu. Hem (1978) suggests that waters with long residence times may evolve to this composition due to the selective permeability of strata to different ions ("membrane effects"), as well as ion exchange and solution/dissolution effects. Membrane effects are described by Freeze and Cherry (1979) as the movement of water and solutes across semipermeable membranes under the influence of hydraulic head gradients, or in the absence of significant hydraulic gradients due to the effects of molecular diffusion. Because of differences in ionic size and charge, divalent cations tend to be filtered more effcctively than monovalent cations. The efficiency of filtering is also affected by the rate of groundwater movement, and the type of clay acting as the semi-permeable barrier. Whether or not it could occur in the relatively shallow Kalahari Group is not clear. The aquifer in this area is slightly confined; perhaps with time, the hydraulic head was sufficient to cause upward leakage of water and Na' through the overlying mudstones, concentrating the Ca" in the remaining solution. As the water type only occurs in these boreholes in a part of the aquifer that has not yet been developed, it has been tentatively attributcd to the boreholes penetrating an aquifer with Ca-Cl, type water, rather than a more widespread effect due to over-pumping and saline intrusion. With more data becoming available to the GRES II Project from the numerous boreholes drilled in northern Lehututu (7782, 7855, 7945, 7944, 7947, LH4A, LH3A, 7946, 7856, 7854), a fuller explanation should be possible.

Ecca aquifers had only Na-CI type waters; the water was generally of higher SO; and lower HCO; than the shallower aquifers. It is not possible to determine any significant pattern in variation of water quality (as indicated by conductivity) across the Project Area for the Ecca aquifers; nOr is there any relation between conductivity and depth to water strike within these aquifers. Due to long residence times in these aquifers, variations are probably dominantly due to locallithological factors, which affect the mineralogy of the strata, and hence the chemistry of the water. However, there were problems with detecting water strikes and Obtaining water samples from different aquifer horizons when mud drilling, and the possibility of the final sample being a mixture of different waters is high for the deep bore holes. Within individual bore holes, analyses for samples from the Kalahari/Mosolotsane water strike and Ecea water strikes are also frequently very similar, indicating the strong possibility of mixing of water from different aquifers in the borchole itself.


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Prior to the Project drilling, rumours of fresh water existing at depth in the Ecca Group aquifers persisted, probably reinforced by water dowsers, despite their very poor success rate. Bath (1980), using 14C data obtained from the Ecca in the Ncojane area, suggested that, under certain conditions, low salinity may persist in Ecca waters of considerable age. In 1989 Petro-Canada drilled three water supply boreholes near Masetleng Pan, some 88km NW of Hukuntsi, one of which struck useable quantities of fresh water at 408m in black, sandy shales of the Boritse Formation. Encouraged by this result, DWA undertook the drilling of 6 deep boreholes under the Consolidated Emergency Programme in 1989/90, in the villages of Monong (BH 6339), Make (BH 6588), Tshane (BH 6160), Ncaang (BH 6161), Ukwi (BH 6629), and Zutshwa (BH 6589) (Geotechnical Consulting Services, 1991), all penetrating to base of Kwetla or top of Boritse Formations.

The Ukwi borehole (total depth 212m) was initially successful, providing usable water (TDS < 1411mg/l), although it has since had a desalination plant installed, indicating deterioration in water quality. Of the remaining boreholes;

• Ncaang (TD 336m) was saline (TDS 10 OOOmg/l) • Zutshwa (TD 432m) was very low yielding and saline (TDS 55 554 mg/l) • Tshane (TD 420m) had an initial TDS of only 8400 mg/l, but this increased during

4.5 hours of development to 18 034 mg/l • Make (TD 370m) had an initial TDS of 4100 mg/l, but again this increased to 10

500 mg/l over a 12 hour air lift development period. • Monong (TD 390m) apparently had an initial TDS of 2200 mg/l, which increased

to a laboratory measured value of 25 550 mg/l during 9 hours of air flushing.

It is interesting to note that the original Petro-Canada borehole drilled at Masetleng Pan, although initially fresh, supposedly became increasingly saline with use over a relatively short period of time (Pers. Comm. L. Heden). This has implications for BH 7927 at Monong. Although the TDS remained less than 7000 mg/l and there was no apparent deterioration in water quality over a 6 hour period of flushing on termination of drilling, it is considered that long term pumping of the borehole is likely to result in a decline of water quality, as has been observed in other boreholes in the area.

Despite problems with identifying water strikes and obtaining samples during mud drilling, it does not appear, from the evidence provided from mixed samples and geophysical logging of Project boreholes, that there is significantly fresher water in the Kweneng than in the Boritse aquifers. All samples from these aquifer horizons are saline, Na-Cl type water. To unequivocally determine the absence of fresher water in the Kweneng aquifer, however, depth sampling or possibly a packer system should be employed to obtain a sample specifically from the aquifer.

The source of salinity in the Kalahari, and possibly Mosolotsane sediments, is probably the presence of highly soluble chloride minerals, or evaporation from a closed basin. If, for some reason, hydrogeological conditions changed, such that groundwater circulation could take place, and a gradual freshening of water would occur, through Na-HCO, type, to Ca-Mg-HCO, type. Butterworth (1982), working on Mogatse Pan to the east of the Project Area, suggested that leaching of salt pans contributes to Na' and Cl' in the pore fluid close to the pan surface. He also observed high moisture contents throughout the unsaturated zone, and increasing salinity towards the pan surface. He suggested this could be due to the upward movement of water and solutes from the saturated zone towards the surface, where water was then lost by evaporation. The evidence indicated that recharge through the pan surface does not occur at present, or has not occurred for a significant period of time. The re-vegetation of some pans could be explained by the fact that, at some point, the upward movement of solutes became insufficient to maintain an environment hostile to plant growth. Butterworth suggested this change could come about, simply because of changes in the quantity and pattern of water movement. However, he does not offer any explanation as to

BRlTISH GEOLOGICAL SURVEY Keyworth Nottingham, UK



28

why hydraulic conditions change, such that pans do become revegetated, and circulating water leaches salts, leading ultimately to fresh groundwater.

The source of salinity in the Kwetla and Ecca aquifers is possibly a result of coonate water in the sediments. Smith (1984) suggested that there may have been marine conditions in this part of the basin during Ecca times. Alternatively, the deep groundwater has aquired salinity as a result of water-rock interaction over a very prolonged time period. Fresh groundwater is encountered in the Boritse and Kweneng Formations in the Kang area (Wellfield Interconsult, 1993), possibly suggesting that the source of salinity within the Project Area is coonate water, with the Kang area being closer to the edge of the basin. However, it must also be taken into account that, in such areas, the Ecca subcrops much closer to the surface (in BH7129, the water strike was at 217m, immediately above the Boritse). If recharge is occuring to the Ecca aquifers in these areas, groundwater flushing will freshen what may have been initially saline, connate waters.




8 CONCLUSIONS

In summary:

29

• Both Kalahari and Mosolotsane groundwaters in the central village area generally tend to be potable. The water type is usually Ca-Mg-HCO" although there are also Na-HCO" CaCl" and Na-Cl types represented.

• The occurence of Ca-Mg-HCO, type waters indicates recharge has occured relatively recently within the central area.

• Although water qUality is generally good in the Kalahari and Mosolotsane aquifers in the central area, nitrate levels in most village samples are high.

• The Occurence of Ca-Cl, type water to the north west of Lehututu village requires further investigation.

• Usable quality water exists to the eastnortheast of the villages (Target Area 4) although here the main producing aquifer is somewhat deeper, and the water quality tends towards brackish. The extent of this somewhat fresher water appears to be very limited (see Figure 9.1, WCS 1995a).

• Outside the central area and Target Area 4, the Kalahari and Mosolotsane aquifers do not yield fresh water.

• The Kwetla and Ecca aquifers yield highly mineralised, saline water throughout the Project Area.

• There is no unequivocal evidence for the existence of fresh water in the Kweneng aquifer in this area, although due to mixing of water from different aquifers during drilling, aquifer specific Kweneng samples could not be obtained.

• The known availability of groundwater of a quality that is suitable for livestock, outside the central village quadrangle, is extremely limited and is likely, over most of the area, to be non-existant (see Figurc 9.1, WCS 1995a).




REFERENCES

Bath AH 1980

Beekman HE & Selaolo ET 1994

Butterworth JS 1982

Cheboratev II 1955

Domenico P A 1972

EEC 1975

Freeze RA & Cherry JA 1979

Geoflux (Pty) Ltd 1994

Geotechnical Consulting Services 1991

GRES II in press (1995)

Hem JD 1978

National Academy of Sciences and 1972 and National Academy of Engineering

Peirce A W 1957

BRITISH GEOLOGICAL SURVEY Keywofth Nottingham, UK

30

Hydrochemistry of the Karoo Aquifers in Southern Botswana. GSlO Project. Evaluation of Underground Water Resources, DGS, Lobatse.

Long term average recharge of a shallow groundwater system in Botswana - A hydrochemical & Isotope Physical Approach. Proc. Conf. Water Down Under 21-25 November 1994

The chemistry of Mogatse Pan - Kgalagadi District. Botswana DGS, Lobatse, Rept JSB/14/82 16pp.

Metamorphism of natural waters in the crust of weathering. Geochim. Cosmochim. Acta. Vol8 pp22-48, 137-170, 198-212.

Concepts and Models in Groundwater Hydrology. McGraw Hill, New York, 446pp.

Proposal for a Council Directive, relating to quality of water for human consumption. Off. J. European Communities No. C214.

Groundwater. Prentice - Hall Inc, New Jersey 604pp.

Groundwater Potential Survey, Toteng/Sehitwa TGLP Area, Final Report. DGS, Lobatse.

Supervision of drilling and construction of boreholes in Monong, Make, Zutshwa, Tshane, Ncaang, and Ukwi Villages of Kgalagadi District: Final Report, Ministry of Mineral Resources and Water Affairs, DWA Gaborone.

Recharge in the western Botswana Kalahari -Groundwater Recharge and Resource Evaluation of the Lehututu Area, Department of Geological Survey, Lobatse, Botswana.

Study and Interpretation of the Chemical Characteristics of Natural Water, US Geol. Survey, Water Supply Paper 1473, 363pp.

Water Quality Criteria, Rept EPA-R3-73-033, Washington, USA.

Saline content of drinking water for livestock Vetinary Review and Annotations, Vol 3, pp37-43.

WELLFIELD CONSULTING SERVICES P,Q.Box 1502 Gaborone, Botswana


31

Smith RA

Steyn DG & Reinach M

US Environmental Protection Agency

Wellfield Consulting Services

Wellfield Consulting Services

Wellfield Interconsult


1984 The lithostratigraphy of the Karoo supergroup in Botswana. Bull. Geol. Surv. Botswana No. 26, DGS, Lobatse.

1939 Water poisoning in man and animals together with a discussion of urinary calculi. Journal of Vet. Sci Animal Industry, Vo112, pt 1, pp 167-230.

1975 Water Programs: National Interim Primary Drinking Water Regulations Federal Register, 40, No. 248.

1995a Matsheng Area Groundwater Investigation, Final Report, for Department of Geological Survey.

1995b Matsheng Area Groundwater Investigation, Technical Report T2, Botanical Survey of the Matsheng Area, for Department of Geological Survey.

1993 Transkalahari Road Groundwater Investigation Project: Final Report, DWA, Gaborone.

WELLFIELD CONSULTING SERVICES P.O.Bcx 1502 Gaborone, Botswana



APPENDIX A

Analysis Results



Aquifer Codes

1 Kalahari Formation 2 Ntane Formation 3 Mosolotsane Formation 4 Kwetla Formation 5 Boritse Formation 6 Kweneng Formation 8 MixedJunkown catagory

Borehole Numbers

7834 Z7350 LH2A W126

Denotes Government Borehole Denotes Private Borehole Denotes GRES II Project Borehole Denotes Well

- 9 indicates no analysis results available.



33

BH_NO Date Fld-pR FlUC TDS FId_DO(%) FId_Alk RC03 C03 Cl 504 N03 N02 F Na K Ca Mg Fe Mn Si02 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/I)

1485 01/01/50 -9.00 -9 1776 -9.0 -9 753 64 441.0 187.0 -9.0 -9.00 1.00 690.0 16.0 4.0 3.0 -9.00 -9.00 -9 8.90 -9 -9

3 1505 01/01/50 -9.00 -9 5660 -9.0 -9 305 o 2755.0 144.0 -9.0 -9.00 2.00 800.0 16.0 509.0 301.0 -9.00 -9.00 -9

7.55 -9 -9 1 1521 / / -9.00 0 544 -9.0 -9 360 0 71.0 25.0 -9.0 -9.00 1.60 60.0 33.0 46.0 41.0 -9.00 -9.00 -9

7.70 650 -9 1 1521 02/H/88 -9.00 -9 482 -9.0 -9 238 33 29.0 15.0 55.0 -9.00 0.98 50.0 24.0 28.0 28.0 -9.00 -9.00 -9

8.02 673 -9 1 1521 12/03/91 6.85 678 463 -9.0 -9 285 19 28.0 14.0 35.0 -9.00 1.00 50.0 30.0 56.8 16.1 0.03 -9.00 -9

7.76 686 -9 1 2649 / / -9.00 -9 700 -9.0 -9 445 0 98.0 13.0 73.0 -9.00 1.20 107.0 7.5 63.0 37.0 -9.00 -9.00 -9

7.10 1080 -9 1 2649 18/12/83 -9.00 -9 629 -9.0 -9 -9 -9 52.0 -9.0 150.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.20 982 -9 1 2649 18/12/83 -9.00 -9 704 -9.0 -9 310 12 86.0 16.0 165.2 0.30 0.71 84.0 7.0 78.0 33.0 -9.00 -9.00 66

7.73 1064 -9 1 2649 09/03/84 -9.00 -9 836 -9.0 -9 351 0 138.0 12.0 250.0 -9.00 -9.00 -9.0 -9.0 204.2 -9.0 -9.00 -9.00 -9

7.50 1306 -9 1 2649 12/03/84 -9.00 -9 853 -9.0 -9 371 0 99.0 13.0 210.0 -9.00 -9.00 -9.0 -9.0 200.2 -9.0 -9.00 -9.00 -9

7.30 1334 -9 1 2827 / / -9.00 -9 612 -9.0 -9 328 0 68.0 16.0 -9.0 -9.00 1.00 112.0 3.6 44.0 12.0 -9.00 -9.00 -9

7. 70 760 -9 1 2827 01/01/50 -9.00 -9 476 -9.0 -9 249 0 60.0 14.0 112.0 -9.00 1.50 107.0 3.6 35.0 9.0 -9.00 -9.00 -9

7.50 780 -9 1

BHJIO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 804 N03 N02 F Na K Ca Hg Fe Hn Si02 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

3585 10/10/80 -9.00 -9 7590 -9.0 -9 -9 -9 1000.0 960.0 -9.0 -9.00 -9.00 -9.0 -9.0 228.3 -9.0 -9.00 -9.00 -9 7.10 12760 -9

4 3585 29/10/81 -9.00 -9 7200 -9.0 -9 -9 -9 350.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.10 11350 -9 4 3692 17/12/81 -9.00 -9 14770 -9.0 -9 -9 -9 5420.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.80 21100 -9 8 3692 04/02/82 -9.00 -9 14000 -9.0 -9 -9 -9 5400.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.30 20000 -9 3 3141 / / -9.00 -9 -9 -9.0 -9 -9 -9 204.0 -9.0 45.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.50 1258 -9 8 3741 / / -9.00 -9 -9 -9.0 -9 -9 -9 196.0 -9.0 50.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.50 1265 -9 8 3141 21/11/81 -9.00 -9 -9 -9.0 -9 -9 -9 106.0 -9.0 150.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.60 1365 -9 8 3141 23/11/81 -9.00 -9 -9 -9.0 -9 -9 -9 110.0 -9.0 215.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.60 1390 -9 8 3835 24/03/82 -9.00 -9 8463 -9.0 -9 -9 -9 2040.0 -9.0 0.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.10 12090 -9 8 3835 24/03/82 -9.00 -9 8596 -9.0 -9 -9 -9 1980.0 -9.0 0.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.50 12280 -9 8 3969 01/11/82 -9.00 -9 8984 -9.0 -9 398 38 3191.0 2885.0 0.5 0.30 2.16 3050.0 41.0 13.0 53.0 -9.00 -9.00 12

8.20 13650 -9 4 3971 17/09/82 -9.00 -9 -9 -9.0 -9 -9 -9 9253.0 -9.0 61.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.50 40135 -9 3

BHJKl Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 003 002 F Ha K Ca Kg Fe Mn Si02 IiSL Data SOurce Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

4237 27/02/84 -9.00 -9 1556 -9.0 -9 398 0 937.0 63.0 66.0 -9.00 -9.00 -9.0 -9.0 184.2 -9.0 -9.00 -9.00 -9 7.70 2431 -9

8 4237 29/02/84 -9.00 -9 1578 -9.0 -9 407 0 951.0 66.0 68.0 -9.00 -9.00 -9.0 -9.0 212.3 -9.0 -9.00 -9.00 -9

7.70 2466 -9 8 4248 06/07/83 -9.00 -9 2652 -9.0 -9 -9 -9 844.0 -9.0 33.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.70 4144 -9 3 4248 08/07/83 -9.00 -9 2652 -9.0 -9 -9 -9 858.0 -9.0 34.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.60 4144 -9 3 4248 07/12/83 -9.00 -9 1640 -9.0 -9 761 77 258.0 205.0 2.9 0.30 0.58 581.0 18.2 7.0 4.0 -9.00 -9.00 50

8.54 2645 -9 3 4248 16/08/84 -9.00 -9 3386 -9.0 -9 902 0 547.0 12.0 25.0 -9.00 -9.00 -9.0 -9.0 76.1 -9.0 -9.00 -9.00 -9

7.70 5290 -9 3 4248 03/11/88 -9.00 4049 2732 -9.0 -9 725 66 876.0 371.0 28.0 -9.00 0.58 920.0 25.0 60.0 26.0 -9.00 -9.00 -9

8.35 4288 -9 3 4248 12/08/94 7.45 4040 2100 58.0 848 683 0 645.0 236.6 22.8 -9.00 5.83 750.0 23.0 28.0 18.0 -9.00 -9.00 16

DGS 7.50 3080 110 3 4251 18/05/83 -9.00 -9 4810 -9.0 -9 -9 -9 1460.0 -9.0 40.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.20 7510 -9 3 4251 19/05/83 -9.00 -9 4950 -9.0 -9 -9 -9 1635.0 -9.0 40.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.60 7740 -9 3 4251 25/07/94 7.48 5840 5400 -9.0 1123 1049 o 1759.0 831.9 -9.0 -9.00 -9.00 1800.0 37.5 30.0 36.0 -9.00 -9.00 15

DGS 7.03 8180 -9 3 4267 04/04/83 -9.00 -9 14650 -9.0 -9 -9 -9 6138.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.70 22890 -9 4

BH)!:) Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 002 F Na K ca Kg Fe Mn Si02 WSL Data SOurce Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

4398 31/08/83 -9.00 -9 104300 -9.0 -9 -9 -9 5640.0 -9.0 33.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 7.00 163000 -9

3 4433 18/12/83 -9.00 -9 38320 -9.0 -9 -9 -9 10000.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

6.90 59875 -9 8 4433 19/12/83 -9.00 -9 32726 -9.0 -9 -9 -9 10000.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

6.90 51135 -9 8 4433 18/12/84 -9.00 -9 110898 -9.0 -9 195 o 63048.0 3200.0 -9.0 -9.00 -9.00 31000.0 200.0 3300.0 3240.0 -9.00 -9.00 16

6.87 103000 -9 8 4492 02/02/84 -9.00 -9 519 -9.0 -9 63 0 50.0 18.5 95.0 -9.00 -9.00 -9.0 -9.0 64.1 -9.0 -9.00 -9.00 -9

7.50 811 -9 1 4492 02/02/84 -9.00 -9 543 -9.0 -9 68 0 58.0 22.0 95.0 -9.00 -9.00 -9.0 -9.0 76.1 -9.0 -9.00 -9.00 -9

7.50 849 -9 8 4516 27/04/88 -9.00 -9 662 -9.0 -9 329 0 65.0 10.2 140.0 -9.00 -9.00 63.0 6.6 83.0 32.0 0.02 0.10 -9

9.63 767 -9 3 4516 02/11/88 -9.00 851 802 -9.0 -9 264 23 56.0 20.0 134.0 -9.00 0.94 60.0 7.0 87.0 36.0 -9.00 -9.00 -9

8.01 875 -9 3 4516 02/05/89 -9.00 -9 646 -9.0 -9 276 22 51.0 8.2 140.0 -9.00 0.42 60.0 7.0 75.0 30.0 -9.00 -9.00 -9

7.69 890 -9 3 4516 13/03/91 6.86 887 674 -9.0 -9 263 26 53.0 17.0 114.0 -9.00 1.00 54.0 6.3 71.5 25.9 -9.00 -9.00 -9

7.95 895 -9 3 4516 16/06/93 -9.00 -9 608 -9.0 -9 302 0 47.0 20.2 132.7 -9.00 1.58 50.0 7.6 50.5 46.2 0.13 -9.00 -9

7.50 901 -9 3 4516 04/08/94 7.49 876 580 101.0 295 303 0 58.0 29.6 93.9 -9.00 0.75 62.0 5.4 76.0 30.0 -9.00 -9.00 76

DGS 7.08 903 235 3

BH_NO Date FldjlH FlOC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 002 F Na K Ca Hq Fe Mn Si02 WSL Data Source LabjlH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

4617 / / -9.00 -9 423 -9.0 -9 312 0 21.0 5.0 80.0 -9.00 -9.00 -9.0 -9.0 116.1 -9.0 -9.00 -9.00 -9 7.80 660 -9

3 4617 / / -9.00 -9 456 -9.0 -9 302 0 22.0 4.0 85.0 -9.00 -9.00 -9.0 -9.0 112.1 -9.0 -9.00 -9.00 -9

7.50 713 -9 3 4617 27/04/88 -9.00 -9 5 -9.0 -9 2 0 30.0 6.2 102.0 -9.00 -9.00 46.0 5.4 52.0 23.0 0.03 0.10 -9

8.20 781 -9 3 4617 02/11/88 -9.00 673 526 -9.0 -9 231 20 29.0 24.0 105.0 -9.00 0.82 50.0 4.9 87.0 21.0 0.00 0.00 -9

8.09 700 -9 3 4611 02/05/89 -9.00 -9 -9 -9.0 -9 -9 -9 -9.0 12.8 117.0 -9.00 0.41 68.0 5.1 58.0 20.0 0.22 0.00 -9

-9.00 -9 -9 3 473 / / -9.00 -9 1037 -9.0 -9 401 0 295.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 77.0 34.0 -9.00 -9.00 -9

7.55 -9 -9 1 473 27/05/88 -9.00 -9 924 -9.0 -9 366 0 260.0 27.0 155.0 -9.00 -9.00 178.0 6.6 94.0 34.0 0.01 0.10 -9

7.30 1820 -9 1 473 02/11/88 -9.00 1541 1130 -9.0 -9 295 30 217.0 45.0 197.0 -9.00 0.60 200.0 6.2 48.0 33.0 0.00 0.00 -9

8.13 1596 -9 1 413 08/05/89 -9.00 -9 1130 -9.0 -9 301 5 236.0 31.0 225.0 -9.00 0.41 230.0 6.0 79.0 20.0 0.21 0.00 -9

7.41 1660 -9 1 473 08/08/90 7.19 1840 1163 -9.0 -9 373 0 342.0 43.2 73.0 -9.00 0.80 210.0 7.0 145.0 30.8 0.56 -9.00 -9

7.77 1772 -9 1 413 12/03/91 6.85 1806 1179 -9.0 -9 343 12 260.0 38.0 67.0 -9.00 0.63 206.0 30.0 90.5 26.6 0.14 -9.00 -9

7.65 1750 -9 1 473 27/10/92 -9.00 -9 1214 -9.0 -9 339 14 265.6 2.9 182.5 -9.00 0.63 206.2 6.2 102.5 23.6 0.10 0.16 -9

7.29 1857 -9 1

BHJI:l Date Fld-pH Fld_BC TDS Fld_DO(%) Fld_Alk BCC3 C03 Cl 504 N03 N02 F Na K Ca Kg Fe MD S102 liSL Data SOurce Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

473 07/06/93 -9.00 1706 1168 -9.0 -9 194 14 266.0 52.3 161.0 -9.00 1.58 200.0 6.1 60.1 37.0 0.24 -9.00 -9 7.72 1800 -9

1 473 14/07/94 6.96 1786 1060 72.0 371 364 0 287.0 40.9 138.4 -9.00 0.50 215.0 5.0 102.0 32.0 -9.00 -9.00 64

DGS 6.72 1800 203 1 4935 29/04/85 -9.00 -9 35487 -9.0 -9 246 o 25524.0 6000.0 1.1 -9.00 0.40 12020.0 74.0 660.0 -9.0 0.10 1.30 -9

7.00 58668 -9 5 4936 10/05/85 -9.00 -9 21003 -9.0 -9 202 o 8863.0 3500.0 0.1 -9.00 0.66 6960.0 52.0 560.0 -9.0 0.15 1.00 -9

7.00 35829 -9 4 4937 08/05/85 -9.00 -9 35386 -9.0 -9 244 o 17016.0 3800.0 0.1 -9.00 0.46 11720.0 68.0 760.0 -9.0 1.01 1.00 -9

7.00 79234 -9 3 499 06/10/75 -9.00 -9 4212 -9.0 -9 426 o 1858.0 206.0 -9.0 -9.00 0.60 440.0 5.5 440.0 340.0 -9.00 -9.00 -9

7.30 6700 -9 1 499 04/02/86 7.35 942 937 -9.0 -9 805 0 177 .0 24.0 360.0 -9.00 1.00 49.0 3.9 136.0 102.0 0.01 0.01 -9

6.98 1333 0 1 499 02/11/88 -9.00 1047 844 -9.0 -9 366 0 111.0 38.0 176.0 -9.00 0.56 40.0 4.6 164.0 46.0 0.00 0.00 -9

7.95 1090 -9 1 5022 16/02/83 -9.00 -9 5500 -9.0 -9 560 24 2400.0 740.0 0.8 0.30 0.23 1840.0 33.0 88.0 90.0 -9.00 -9.00 58

8.10 9120 -9 8 5022 23/08/85 -9.00 -9 4466 -9.0 -9 -9 -9 1843.0 400.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.50 8378 -9 8 5127 13/01/86 -9.00 -9 182974 -9.0 -9 9512 o 78983.0 8920.0 -9.0 -9.00 7.00 40000.0 240.0 560.0 14.6 1.76 0.01 -9

8.00 285897 -9 1 5127 14/01/86 -9.00 -9 191716 -9.0 -9 9756 083662.0 6587.0 -9.0 -9.00 3.10 48000.0 240.0 560.0 19.4 0.70 0.01 -9

7.90 299556 -9 1

BR)!:) Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk RC03 C03 Cl S04 N03 N02 F Na K ca Kg Fe Mn Si02 WSL Data SOurce Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

5127 18/10/89 -9.00 -9 380 -9.0 -9 71 0 166.0 28.1 0.5 0.30 0.05 133.0 7.0 -9.0 6.0 -9.00 -9.00 5 7.07 770 -9

1 5128 19/01/86 -9.00 -9 236831 -9.0 -9 3732 o 84066.0 9600.0 -9.0 -9.00 3.60 57600.0 160.0 20.0 24.3 0.01 0.01 -9

8.60 370049 -9 1 5128 20/01/86 -9.00 -9 201160 -9.0 -9 9634 087987.0 6130.0 -9.0 -9.00 7.10 45000.0 240.0 560.0 19.5 0.75 0.01 -9

8.90 314312 -9 1 5128 21/08/94 9.44 19999 164000 -9.0 -9 8540 o 85104.0 10994.3 -9.0 -9.00 -9.00 62000.0 500.0 1.0 -9.0 -9.00 -9.00 21

DGS 7.83 165400 -9 1 5283 25/02/86 -9.00 -9 986 -9.0 -9 302 0 310.0 12.0 46.0 -9.00 1.05 102.0 228.0 56.0 63.0 0.01 0.01 -9

7.50 1891 -9 1 5283 17/03/86 -9.00 -9 1044 -9.0 -9 280 0 128.0 7.0 42.0 -9.00 0.88 80.0 6.8 48.1 31.6 1.42 0.01 -9

7.98 989 -9 1 5283 19/03/86 -9.00 -9 -9 -9.0 -9 285 0 115.0 8.0 45.0 -9.00 -9.00 -9.0 4.4 44.1 41.3 0.05 0.01 -9

8.22 984 -9 1 5283 27/04/88 -9.00 -9 650 -9.0 -9 293 0 110.0 11.0 46.8 -9.00 -9.00 83.0 4.2 64.0 19.9 0.02 0.10 -9

8.76 750 -9 1 5283 02/11/88 -9.00 792 530 -9.0 -9 205 25 85.0 26.0 51.0 -9.00 0.70 90.0 4.2 41.0 20.0 0.00 0.00 -9

8.16 797 -9 1 5283 13/03/91 6.88 826 587 -9.0 -9 255 17 80.0 16.0 41.0 -9.00 0.79 78.0 7.5 60.2 16.7 -9.00 -9.00 -9

8.05 844 -9 1 5283 16/06/93 -9.00 -9 532 -9.0 -9 290 24 72.0 25.5 50.0 -9.00 1.58 75.0 4.0 64.9 30.6 0.08 -9.00 -9

7.59 846 -9 1 5283 04/08/94 7.26 850 500 70.0 277 281 0 87.0 15.0 57.2 -9.00 0.47 80.0 3.4 61.0 19.0 -9.00 -9.00 75

DGS 6.87 867 214 1

BH_OO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 504 003 N02 F Na K Ca Mg Fe Mn S102 \jSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

5284 03/02/86 -9.00 -9 600 -9.0 -9 324 0 110.0 7.0 69.0 -9.00 1.20 80.0 18.0 16.0 32.0 0.10 0.01 -9 7.40 1045 -9

1 5284 14/03/86 -9.00 -9 812 -9.0 -9 337 0 104.0 9.0 120.0 -9.00 1.40 100.0 14.0 16.0 29.0 0.05 0.01 -9

7.60 1175 -9 1 5285 17/03/86 -9.00 -9 926 -9.0 -9 215 0 103.0 15.0 136.0 -9.00 1.00 20.0 5.0 4.0 97.0 0.05 0.01 -9

7.00 1260 -9 1 5285 17 /03/86 -9.00 -9 818 -9.0 -9 205 0 75.0 17.0 120.0 -9.00 1.04 20.0 5.0 8.0 39.0 0.05 0.01 -9

7.20 1265 -9 1 5285 28/03/86 -9.00 -9 846 -9.0 -9 220 0 83.0 11.0 230.0 -9.00 1.30 90.0 3.8 45.0 37.0 0.05 0.01 -9

7.90 1227 -9 1 5285 30/03/86 -9.00 -9 700 -9.0 -9 280 0 83.0 14.0 200.0 -9.00 1.20 98.0 6.4 37.0 33.0 0.01 0.01 -9

8.10 1161 -9 1 5448 07/08/86 -9.00 -9 478 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

-9.00 -9 -9 1 5448 07/08/86 -9.00 -9 478 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

-9.00 -9 -9

5448 07/12/86 -9.00 -9 554 -9.0 -9 241 0 62.0 56.0 43.0 -9.00 0.56 93.0 1.4 24.4 22.9 0.01 0.10 -9 7.90 806 -9

1 5448 09/12/86 -9.00 -9 530 -9.0 -9 276 0 64.0 54.0 32.0 -9.00 0.56 93.0 2.0 32.0 30.0 0.01 0.10 -9

7.70 862 -9 1 5448 12/03/91 7.01 763 517 -9.0 -9 282 14 44.0 21.0 54.0 -9.00 1.00 64.0 3.1 64.2 13.9 -9.00 -9.00 -9

7.62 734 -9 1 5448 27/10/92 -9.00 -9 556 -9.0 -9 283 14 43.4 17 .3 59.3 -9.00 0.63 59.3 2.1 69.2 12.8 -9.00 0.11 -9

7.31 769 -9

BH_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 002 F Na K Ca Mg Fe Mn S102 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

5448 07/06/93 -9.00 720 500 -9.0 -9 302 0 22.7 29.7 28.9 -9.00 1.58 68.0 3.1 60.8 8.8 0.62 -9.00 -9 7.84 767 -9

1 5448 31/07/94 7.19 760 480 -9.0 281 305 0 48.0 19.6 43.6 -9.00 0.60 70.0 6.5 64.0 16.0 -9.00 -9.00 64

DGS 6.81 759 -9 1 5668 21/09/89 -9.00 -9 1820 -9.0 -9 671 62 320.0 194.0 8.1 -9.00 1.30 609.0 13.0 4.9 3.5 0.06 0.00 14

8.91 2350 -9 3 5793 08/05/88 -9.00 -9 618 -9.0 -9 305 0 145.0 0.1 46.8 -9.00 -9.00 96.0 5.4 63.0 13.6 0.04 0.10 -9

7.90 891 -9 1 .;j 5846 09/03/88 -9.00 -9 488 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.35 743 -9 1 5846 13/03/90 7.14 845 584 -9.0 -9 260 12 94.0 15.0 27.0 -9.00 1.00 82.0 4.6 46.2 21.4 -9.00 -9.00 -9

7.89 839 -9 1 5846 16/06/93 -9.00 -9 590 -9.0 -9 298 0 108.0 23.0 32.0 -9.00 1.58 87.0 4.5 53.7 33.1 -9.00 -9.00 -9

7.78 895 -9 1 5947 20/07/88 -9.00 -9 860 -9.0 -9 425 0 284.0 20.8 68.0 -9.00 1.10 210.0 10.0 73.0 28.0 0.90 0.10 -9

7.58 1366 -9 3 5947 11/08/88 -9.00 -9 534 -9.0 -9 320 0 79.0 39.7 70.2 0.30 1.06 19.0 10.4 64.0 68.0 -9.00 -9.00 30

7.45 960 -9 3 5947 13/08/88 -9.00 -9 648 -9.0 -9 338 0 104.0 31.7 71.6 0.30 0.85 88.0 11.5 59.0 41.0 -9.00 -9.00 75

7.50 1060 -9 3 5947 24/09/88 -9.00 -9 748 -9.0 -9 234 10 259.0 45.0 69.0 -9.00 0.90 170.0 10.0 64.0 28.0 0.01 0.00 -9

8.05 1440 -9 3 5947 12/03/91 6.69 1480 920 -9.0 -9 390 19 222.0 34.0 53.0 -9.00 1.26 173.0 8.1 81.0 26.2 -9.00 -9.00 -9

7.62 1459 -9 3

BHJlO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 804 003 N02 F Na K ca Mg Fe Mn Si02 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

5947 27/10/92 -9.00 -9 1448 -9.0 -9 426 21 440.4 69.1 68.8 -9.00 1. 00 345.4 9.9 93.1 30.8 -9.00 0.11 -9 7.54 2379 -9

3 5947 23/04/93 -9.00 -9 890 -9.0 -9 240 19 270.0 35.4 73.2 -9.00 1.26 200.0 9.0 87.4 28.5 -9.00 -9.00 -9

8.25 1515 -9 3 5947 23/04/93 -9.00 -9 1058 -9.0 -9 291 21 349.0 2.9 73.9 -9.00 1.26 280.0 10.3 60.0 27.2 -9.00 -9.00 -9

8.19 1943 -9 3 5947 07/06/93 -9.00 1429 968 -9.0 -9 398 0 224.0 28.8 57.5 -9.00 2.00 175.0 8.0 79.4 36.5 0.26 -9.00 -9

7.57 1494 -9 3 5947 03/08/94 7.08 2320 1162 -9.0 373 468 0 380.0 45.3 73.9 -9.00 0.93 315.0 23.5 76.0 28.0 -9.00 -9.00 60

DGS 6.88 2110 -9 1 5948 13/10/88 -9.00 -9 810 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.54 1206 -9 1 5948 15/10/88 -9.00 -9 776 -9.0 -9 386 0 173.0 30.2 80.7 0.30 1.11 135.0 9.4 44.0 53.0 -9.00 -9.00 61

7.15 1290 -9 1 5948 05/05/93 -9.00 -9 672 -9.0 -9 226 13 186.0 30.5 82.5 -9.00 1.00 130.0 6.0 86.7 28.0 -9.00 -9.00 -9

8.12 1205 -9 1 5948 07/05/93 -9.00 -9 840 -9.0 -9 352 5 186.0 25.9 76.1 -9.00 0.79 140.0 5.7 91.8 27.4 -9.00 -9.00 -9

8.02 1426 -9 1 5948 07/06/93 -9.00 1296 918 -9.0 -9 417 0 175.0 30.5 72.7 -9.00 1.58 129.0 5.8 49.7 53.5 0.08 -9.00 -9

7.86 1353 -9 1 5948 03/08/94 6.91 1436 840 -9.0 387 415 0 201.0 32.2 71.7 -9.00 0.66 148.0 5.2 94.0 30.0 -9.00 -9.00 62

DGS 6.65 1450 -9 1 5967 14/11/88 -9.00 -9 618 -9.0 -9 373 0 85.0 35.0 173.0 -9.00 1.30 92.0 16.0 75.0 39.0 0.01 0.01 -9

7.66 930 -9 1

BHJIO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HCC3 C03 Cl S04 003 002 F Na K Ca Hq Fe Mn Si02 liSt Data Source Lab-pH Lab_EC Eh (mV) Aquifer (us/an) (mg/l) (mg/l)

5968 07/07/88 -9.00 -9 7332 -9.0 -9 293 o 3758.0 186.0 245.0 -9.00 0.57 1300.0 20.0 448.0 378.0 0.00 0.00 -9 7.35 10360 -9

1 5968 07/07/88 -9.00 -9 7180 -9.0 -9 505 o 3899.0 284.0 211.0 -9.00 0.62 1700.0 20.0 520.0 326.0 0.05 0.10 -9

7.61 10810 -9 1 5968 08/10/88 -9.00 -9 8542 -9.0 -9 120 o 4849.0 379.0 83.0 -9.00 0.48 1600.0 42.0 1124.0 456.0 0.00 0.00 -9

7.31 11719 -9 1 5968 29/01/90 -9.00 -9 17974 -9.0 -9 331 o 7077.0 3.7 6.7 -9.00 0.17 1850.0 46.0 1302.0 862.0 1.27 -9.00 -9

7.20 17593 -9 1 5968 31/01/90 -9.00 -9 15344 -9.0 -9 343 o 5840.0 346.0 39.0 -9.00 0.19 1700.0 35.0 1048.0 712.0 -9.00 -9.00 -9

7.54 15463 -9 1 6043 10/10/88 -9.00 -9 8556 -9.0 -9 71 o 2233.0 3182.0 0.0 -9.00 0.46 1900.0 20.0 660.0 148.0 0.00 0.00 -9

7.54 10199 -9 4 6043 18/10/88 -9.00 -9 8916 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

-9.00 10579 -9 4 6043 01/11/88 -9.00 -9 8730 -9.0 -9 39 o 2154.0 3243.0 0.0 -9.00 0.35 2000.0 25.0 676.0 116.0 0.01 0.01 -9

6.15 10010 -9 4 6043 11/05/89 -9.00 -9 8958 -9.0 -9 74 o 2358.0 3411.0 0.1 -9.00 0.21 2100.0 17.0 971.0 84.0 1.19 0.00 -9

7.15 10720 -9 4 6043 13/05/89 -9.00 -9 5236 -9.0 -9 217 10 1136.0 2164.0 23.9 -9.00 0.19 1060.0 12.0 500.4 28.0 0.01 0.00 -9

7.42 6550 -9 4 6043 12/08/94 7.71 10000 8860 -9.0 44 49 o 2312.0 3470.5 -9.0 -9.00 -9.00 2250.0 90.0 580.0 138.0 -9.00 -9.00 21

DGS 6.69 12500 68 4 6046 15/10/88 -9.00 -9 668 -9.0 -9 329 0 159.0 13.0 79.0 -9.00 1.20 120.0 8.0 94.0 23.0 0.00 0.00 -9

7.36 1094 -9 1

BUO Date Fld..pH FlUC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 1102 F Na K Ca IIg Fe Mn S102 IISL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

6046 29/04/93 -9.00 -9 780 -9.0 -9 254 14 203.4 46.5 84.2 -9.00 0.79 250.0 10.4 25.2 17.7 -9.00 -9.00 -9 8.31 1371 -9

1 6046 02/05/93 -9.00 -9 960 -9.0 -9 154 12 330.3 44.0 81.1 -9.00 0.79 180.0 9.4 75.9 18.7 -9.00 -9.00 -9

8.12 1652 -9 1 6046 07/06/93 -9.00 1294 868 -9.0 -9 443 0 185.0 47.3 73.1 -9.00 1.58 200.0 10.0 72.1 28.7 -9.00 -9.00 -9

7.51 1465 -9 1 6046 03/08/94 7.03 1714 1008 -9.0 381 468 0 272.0 55.4 58.9 -9.00 0.74 290.0 11.5 56.0 18.0 -9.00 -9.00 62

DGS 6.88 1830 -9 1 6088 05/09/88 -9.00 -9 802 -9.0 -9 462 0 116.0 49.0 65.0 -9.00 0.74 155.0 7.4 74.0 24.0 0.01 0.01 -9

7.09 1128 -9 1 6088 04/08/94 7.32 1217 760 -9.0 406 432 0 116.0 36.7 80.6 -9.00 0.46 158.0 5.2 69.0 19.0 -9.00 -9.00 65

DGS 6.83 1240 -9 1 6160 31/03/90 -9.00 -9 18034 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 1.20 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.79 27400 -9 4 6160 03/04/90 -9.00 -9 17580 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 1.60 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.15 26800 -9 4 6186 30/11/88 -9.00 -9 9530 -9.0 -9 1171 72 3820.0 967.0 0.0 -9.00 0.84 3400.0 110.0 40.0 20.0 0.01 0.01 -9

7.96 13873 -9 3 6257 12/03/89 -9.00 -9 1544 -9.0 -9 744 56 291.0 123.0 31.0 -9.00 1.20 486.0 16.0 35.0 4.2 0.14 0.00 -9

8.25 2606 -9 3 6257 14/06/89 -9.00 -9 1590 -9.0 -9 909 48 365.0 145.0 12.0 -9.00 1.80 625.0 13.0 4.4 3.7 0.23 0.00 145

8.73 2350 -9 3 6257 14/06/89 -9.00 -9 1555 -9.0 -9 896 37 333.0 114.0 16.0 -9.00 1.90 605.0 13.0 4.3 3.6 0.52 0.00 30

8.64 2350 -9 3

BHJlO Date Fld-pH Fld_EC TDS Fld_DO(t) Fld_Alk HC03 C03 Cl 504 N03 N02 F Na K Ca Mg Fe Mn Si02 IISL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

6251 14/03/91 1.94 2410 1696 0.0 -9 172 50 326.0 130.0 42.0 -9.00 1.58 590.0 10.0 3.1 23.1 0.16 -9.00 -9 8.35 2661 -9

3 6251 11/06/93 -9.00 2226 1596 -9.0 -9 686 14 341.0 112.0 39.4 -9.00 2.00 515.0 12.6 6.4 9.1 -9.00 -9.00 -9

1.84 2166 -9 3 6321 19/09/89 -9.00 -9 11112 -9.0 -9 316 30 3036.6 4041.0 242.0 -9.00 0.16 3961.6 40.5 158.2 107.0 0.00 0.00 -9

1.89 15306 -9 3 6339 26/01/90 -9.00 -9 25532 -9.0 -9 -9 -9 -9.0 -9.0 5.4 -9.00 0.34 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.10 39360 -9 5 6339 01/02/90 -9.00 -9 9818 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 0.16 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.83 13134 -9 5 6339 01/02/90 -9.00 -9 10160 -9.0 -9 -9 -9 -9.0 -9.0 4.6 -9.00 0.18 9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.94 14098 -9 5 6339 11/02/90 -9.00 -9 9820 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 1.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.93 13388 -9 5 6339 11/02/90 -9.00 -9 10022 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 1.05 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.07 13502 -9 5 6339 08/03/90 -9.00 -9 20722 -9.0 -9 143 1 5589.0 6311.0 44.0 -9.00 0.64 6200.0 48.0 355.0 193.0 -9.00 -9.00 -9

1.93 32418 -9 5 6339 10/03/90 -9.00 -9 8758 -9.0 -9 335 19 3049.0 3020.0 0.0 -9.00 0.90 3200.0 14.0 113.0 63.0 -9.00 -9.00 -9

8.09 13173 -9 5 6339 21/06/91 -9.00 -9 21105 -9.0 -9 -9 -9 -9.0 -9.0 28.0 -9.00 0.63 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.80 32911 -9 5 6339 21/06/91 -9.00 -9 21012 -9.0 -9 -9 -9 -9.0 -9.0 26.1 -9.00 0.63 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.84 32870 -9 5

BH_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 804 N03 N02 F Ha K Ca Hq Fe Mn S102 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

6339 21/06/91 -9.00 -9 21094 -9.0 -9 -9 -9 -9.0 -9.0 23.0 -9.00 0.63 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 7.79 32977 -9

5 6339 09/11/91 -9.00 -9 1321 -9.0 -9 84 0 575.0 63.0 0.0 -9.00 0.20 420.0 1.9 4.2 1.4 0.37 -9.00 3

7.42 2585 -9 5 6339 09/11/91 -9.00 -9 10400 -9.0 -9 340 13 3075.0 3323.0 0.0 -9.00 0.40 3200.0 15.0 176.0 54.0 0.50 -9.00 10

7.68 14654 -9 5 6339 25/09/92 -9.00 -9 1308 -9.0 -9 46 0 559.4 193.4 0.0 -9.00 0.25 411.3 1.7 11.8 2.3 0.06 -9.00 -9

6.59 2410 -9 5 6457 15/07/89 -9.00 -9 1004 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.76 1481 -9 1 6457 28/09/89 -9.00 -9 508 -9.0 -9 -9 -9 -9.0 -9.0 98.6 -9.00 0.61 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.17 984 -9 1 6457 28/09/89 -9.00 -9 572 -9.0 -9 -9 -9 -9.0 -9.0 95.2 -9.00 0.62 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.41 1023 -9 1 6481 21/07/89 -9.00 -9 18328 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 0.28 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.99 33920 -9 5 6481 08/08/89 -9.00 -9 44010 -9.0 -9 443 o 5960.0 4100.0 0.0 -9.00 0.26 6400.0 43.0 23.0 12.0 0.07 0.00 -9

7.51 68782 -9 5 6481 01/09/89 -9.00 -9 28040 -9.0 -9 327 12 6321.0 6171.0 0.0 -9.00 0.85 6060.0 40.0 230.0 80.0 2.80 0.00 15

8.31 21900 -9 5 6482 18/08/89 -9.00 -9 578 -9.0 -9 -9 -9 -9.0 -9.0 56.3 -9.00 0.52 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

6.77 816 -9 3 6482 08/12/89 -9.00 -9 510 -9.0 -9 162 14 46.0 17.7 157.0 -9.00 0.48 70.0 4.5 35.0 36.0 2.57 0.13 -9

7.66 735 -9 3

BR_NO Date FldJPH Fld_EC TDS Fld_DO(%) Fld_Alk He03 C03 Cl 304 N03 002 F Na K Ca Kg Fe Mn S102 WSL Data Source LabJPH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

6482 14/12/89 -9.00 0 584 -9.0 -9 243 14 50.0 16.9 149.0 -9.00 0.44 14.0 4.5 36.0 39.0 0.06 0.09 -9 1.55 861 -9

3 6482 09/08/94 1.36 816 500 -9.0 265 288 0 50.0 11.2 89.8 -9.00 0.40 68.0 4.2 15.0 16.0 -9.00 -9.00 . 54

DGS 1.50 834 149 3 6484 18/11/89 -9.00 -9 596 -9.0 -9 314 0 31.0 15.0 116.0 -9.00 0.56 52.0 5.1 85.0 21.0 -9.00 -9.00 -9

6.98 816 -9 1 6484 01/12/89 -9.00 -9 598 -9.0 -9 302 9 40.0 9.9 0.6 -9.00 0.58 56.0 4.1 12.0 1.8 0.32 0.00 -9

7.36 888 -9 1 6484 01/12/89 -9.00 -9 610 -9.0 -9 324 0 46.0 11.5 21.9 -9.00 0.52 54.0 4.8 99.0 1.6 0.43 0.00 -9

1.05 880 -9 1 6484 09/08/94 1.03 836 540 -9.0 321 339 0 41.0 13.1 88.5 -9.00 0.46 52.0 4.0 88.0 20.0 -9.00 -9.00 12

DGS 1.26 843 111 1 6498 22/02/90 -9.00 -9 32554 -9.0 -9 -9 -9 -9.0 -9.0 4.9 -9.00 1.10 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.90 50052 -9 3 6559 22/03/90 -9.00 -9 21838 -9.0 -9 -9 -9 -9.0 -9.0 32.0 -9.00 9.60 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.36 38181 -9 8 6588 01/01/91 -9.00 -9 10500 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

-9.00 -9 -9 5 6588 01/01/91 -9.00 -9 4100 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

-9.00 -9 -9 5 6589 21/03/90 -9.00 -9 55554 -9.0 -9 1904 17 21921.1 -9.0 65.6 -9.00 1.50 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

8.46 88313 -9 8 6630 28/12/90 -9.00 -9 21204 -9.0 -9 -9 -9 -9.0 -9.0 8.9 -9.00 0.40 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

1.52 33891 -9 4

BHJK) Date Fld-pH Fld_EC TUS Fld_DO(%) Fld_Alk HCC3 C03 Cl S04 N03 N02 F Na K Ca Kg Fe MD S102 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

6630 28/12/90 -9.00 -9 20594 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 0.40 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 7.53 32640 -9

4 6630 28/12/90 -9.00 -9 21204 -9.0 -9 -9 -9 -9.0 -9.0 8.9 -9.00 0.40 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.52 33891 -9 4 6630 28/12/90 -9.00 -9 20594 -9.0 -9 -9 -9 -9.0 -9.0 0.0 -9.00 0.40 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.53 32640 -9 4 6753 30/10/90 -9.00 -9 21580 -9.0 -9 -9 -9 -9.0 -9.0 395.0 -9.00 1.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

7.30 35401 -9 8 7412 17/09/93 -9.00 -9 41120 -9.0 -9 1232 252 11029.0 9151.8 6.4 -9.00 10.00 13250.0 45.0 3.8 4.8 0.50 0.02 12

8.65 64570 -9 3 7412 17 /09/93 -9.00 -9 44020 -9.0 -9 1312 365 11233.0 10616.0 1.5 -9.00 10.00 14500.0 49.0 1.8 2.1 0.02 -9.00 -9

6.91 73318 -9 3 7412 18/09/93 -9.00 -9 41120 -9.0 -9 1133 294 10733.6 9283.4 3.8 -9.00 10.00 13000.0 42.5 4.0 4.9 0.40 0.00 12

8.64 64893 -9 3 7412 18/09/93 -9.00 -9 41360 -9.0 -9 1201 298 11078.3 9464.5 2.6 -9.00 10.00 13600.0 42.0 4.0 5.1 0.43 -9.00 12

8.80 67475 -9 3 7412 19/09/93 -9.00 -9 40800 -9.0 -9 1172 287 10979.8 9513.9 3.6 -9.00 10.00 13500.0 45.0 4.1 5.1 0.40 -9.00 12

8.87 67260 -9 3 7412 19/09/93 -9.00 -9 42960 -9.0 -9 1127 321 13049.0 9415.1 2.9 -9.00 10.00 14000.0 48.0 3.2 4.1 0.06 -9.00 -9

8.79 67342 -9 3 7412 20/09/93 -9.00 -9 41320 -9.0 -9 1160 317 10930.5 9530.0 3.2 -9.00 10.00 13000.0 40.0 4.0 5.2 0.50 -9.00 12

8.85 69090 -9 3 7646 05/08/94 -9.00 -9 -9 -9.0 -9 183 o 6460.0 867.0 6.4 -9.00 0.63 5400.0 41.0 293.6 193.8 0.06 0.24 -9

DWA 7.10 23110 -9 4

BH_NO Date Fld-pH Fld_EC TD5 Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 N02 F Na K Ca Hq Fe Mn 5102 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (uS/an) (mg/l) (mg/l)

7125 10/11/94 -9.00 -9 22006 -9.0 -9 304 24 7753.1 5973.0 0.0 -9.00 0.79 7600.0 27.0 225.3 67.0 7.28 0.00 -9 DWA 8.20 35378 -9

5 7128 08/12/94 -9.00 -9 21102 -9.0 -9 74 19 5304.7 7726.0 0.0 -9.00 0.79 6600.0 230.0 469.9 85.4 6.85 0.00 -9

DWA 8.00 32412 -9 4 7782 23/09/94 -9.00 1755 -9 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9

GEOFLUX -9.00 1755 -9 1 7829 15/03/95 -9.00 27200 22700 -9.0 -9 459 o 7253.0 6621.2 -9.0 -9.00 -9.00 9000.0 15.0 150.0 150.0 -9.00 -9.00 9 264 DGS 7.25 28400 -9 5 7829 27/04/95 7.00 36400 24700 -9.0 440 537 o 10477.0 3542.8 -9.0 -9.00 -9.00 9000.0 240.0 230.0 130.0 -9.00 -9.00 10 FINAL DGS 7.89 32400 157 5 7831 17/11/94 7.00 11000 6270 -9.0 -9 281 o 3436.0 583.6 -9.0 -9.00 -9.00 1700.0 57.0 415.0 210.0 -9.00 -9.00 34 81 DGS 7.01 10300 -9 3 7831 20/01/95 -9.00 13000 7480 -9.0 -9 342 o 3605.0 1019.3 -9.0 -9.00 -9.00 2100.0 51.0 380.0 210.0 -9.00 -9.00 38 252 DGS 7.23 11300 -9 4 7831 21/01/95 7.50 12000 -9 -9.0 257 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 287 DGS -9.00 12000 -9 5 7832 27/01/95 8.35 -9 115300 -9.0 -9 1830 065246.0 13727.4 -9.0 -9.00 -9.00 45000.0 •••.• 20.0 100.0 -9.00 -9.00 37 70 DGS 7.84 155000 118 1 7832 02/02/95 -9.00 38800 27000 -9.0 671 610 o 13617.0 7738.8 -9.0 -9.00 -9.00 10500.0 160.0 150.0 120.0 -9.00 -9.00 15 248 DGS 7.77 31700 -9 4 7832 20/02/95 -9.00 37500 22500 -9.0 -9 688 o 11039.0 61.7 -9.0 -9.00 -9.00 9200.0 300.0 140.0 100.0 -9.00 -9.00 12 FINAL DGS 7.44 31500 -9 8 7833 31/01/95 -9.00 -9 36000 -9.0 -9 659 017787.0 5055.3 -9.0 -9.00 -9.00 13000.0 300.0 330.0 33.0 -9.00 -9.00 22 51 DGS 7.53 48900 181 1

BHJIO Date Fld-pH Fld_EC 10S Fld_DO(%) Fld_Alk BCC3 C03 Cl 804 003 002 F Na K Ca Hg Fe MD S102 WSL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

7833 02/02/95 -9.00 49500 34850 45.0 553 488 016170.0 6617.1 -9.0 -9.00 -9.00 13000.0 165.0 330.0 160.0 -9.00 -9.00 20 268 DGS 7.61 48200 -9 4 7835 14/02/95 -9.00 39500 -9 -9.0 433 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 255 DGS -9.00 39500 117 5 7836 16/02/95 -9.00 -9 100000 -9.0 2440 2752 1015 97734.0 8672.1 -9.0 -9.00 -9.00 37500.0 ..... 1.0 15.0 -9.00 -9.00 13 53 IlGS 8.21 97900 119 1 7836 16/02/95 -9.00 -9 100000 -9.0 -9 2752 1015 47734.0 8672.1 -9.0 -9.00 -9.00 37500.0 •••.• 1.0 15.0 -9.00 -9.00 13 FINAL IlGS 8.21 97900 -9 1 7837 23/02/95 -9.00 28200 18920 50.0 634 550 o 8729.0 2198.9 -9.0 -9.00 -9.00 5000.0 300.0 650.0 580.0 -9.00 -9.00 17 77 IlGS 7.25 25800 -9 3 7837 24/02/95 -9.00 29100 18920 48.0 -9 545 o 8665.0 2198.9 -9.0 -9.00 -9.00 5000.0 300.0 650.0 580.0 -9.00 -9.00 13 FINAL IlGS 7.31 25800 -9 3 7838 27/02/95 -9.00 18980 13200 -9.0 -9 433 o 4653.0 3511.6 -9.0 -9.00 -9.00 4400.0 44.0 120.0 108.0 -9.00 -9.00 9 261 IlGS 7.76 18700 -9 4 7838 10/03/95 -9.00 17670 12800 -9.0 354 430 o 4621.0 3394.9 -9.0 -9.00 -9.00 4400.0 47.5 130.0 120.0 -9.00 -9.00 11 FINAL DGS 7.79 18700 178 4 7854 22/02/95 -9.00 670 466 -9.0 349 -9 -9 -9.0 -9.0 41.9 -9.00 1.26 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 23 DWA 7.90 744 -9 1 7854 20/03/95 -9.00 757 406 -9.0 3ll 372 0 31.0 10.9 -9.0 0.00 1.44 34.0 8.4 58.0 32.0 -9.00 -9.00 51 FINAL DGS 7.48 680 -9 1 7855 27/02/95 -9.00 1900 3500 -9.0 306 251 o 1960.0 47.3 -9.0 -9.00 -9.00 800.0 77.5 210.0 230.0 -9.00 -9.00 55 34 DGS 7.57 6060 -9 1 7856 01/03/95 -9.00 596 438 -9.0 -9 390 0 14.0 8.5 5.7 3.90 LlO 78.0 20.5 35.0 20.0 -9.00 -9.00 66 39 IlGS 7.97 597 -9 1

BHJIO Date Fld-pH Fld_EC TD8 Fld_DO(%) Fld_Alk HC03 C03 Cl 804 003 N02 F Na K Ca Hg Fe MD 8i02 IISL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (us/an) (mg/l) (mg/l)

7856 01/03/95 -9.00 591 400 -9.0 423 310 0 13.0 12.1 19.3 9.60 1.13 71.0 17.5 30.0 15.0 -9.00 -9.00 58 27 DGS 7.65 598 -9 1 7866 02/11/94 7.17 1206 880 -9.0 343 329 0 167.0 82.8 118.6 -9.00 0.64 190.0 10.5 52.0 20.0 -9.00 -9.00 70 18.5 DGS 7.70 1340 249 1 7868 04/11/94 -9.00 831 510 -9.0 201 162 0 37.0 10.6 186.0 -9.00 0.80 36.0 8.5 70.0 17.0 -9.00 -9.00 66 13.5 DGS 7.34 744 224 1 7869 05/11/94 -9.00 1009 640 -9.0 278 361 0 132.0 21.2 24.9 -9.00 0.81 160.0 20.0 23.0 18.0 -9.00 -9.00 75 11.5 DGS 7.45 1060 188 1 7871 16/11/94 -9.00 -9 13440 -9.0 -9 153 o 4418.0 4866.2 -9.0 -9.00 -9.00 5000.0 50.0 180.0 64.0 -9.00 -9.00 3 270 DGS 7.52 19300 -9 4 7871 18/11/94 -9.00 21000 14140 -9.0 -9 153 o 4362.0 5277.2 -9.0 -9.00 -9.00 4750.0 47.5 420.0 130.0 -9.00 -9.00 4 450 DGS 7.06 19200 -9 5 7872 21/11/94 -9.00 627 420 -9.0 -9 283 0 38.0 18.6 32.9 -9.00 0.88 47.0 7.8 54.0 25.0 -9.00 -9.00 63 17 DGS 7.68 682 235 1 7872 22/11/94 -9.00 683 442 38.0 309 349 0 43.0 22.4 20.9 -9.00 0.83 118.0 9.5 23.0 12.0 -9.00 -9.00 52 60 DGS 8.10 738 -9 1 7872 10/05/95 7.86 667 452 59.0 319 301 0 40.0 29.6 46.9 -9.00 1.37 64.0 9.5 49.0 22.0 -9.00 -9.00 45 STEP_1 DGS 7.65 730 -9 1 7872 11/05/95 8.27 650 480 55.0 303 3ll 0 34.0 57.4 33.5 -9.00 1.40 86.0 11.2 41.0 19.0 -9.00 -9.00 42 STEP_6 DGS 7.64 761 -9 1 7872 12/05/95 8.12 658 422 55.0 283 320 0 36.0 24.0 30.7 -9.00 1.36 92.0 11.2 37.0 17.0 -9.00 -9.00 42 CR_24 DGS 7.55 728 -9 1 7872 13/05/95 8.56 661 434 58.0 296 3ll 0 36.0 22.9 29.8 -9.00 1.32 88.0 11.4 37.0 17.0 -9.00 -9.00 42 CR_48 DGS 7.63 726 -9 1

BR_NO Date Fld-pR Fld_EC TD5 Fld_DO(%) Fld_Alk RC03 C03 Cl S04 N03 N02 F Na K Ca Kg Fe Mn 5i02 W5L Data Source Lab-pR Lab_EC Eh (mV) Aquifer (US/cm) (1119/1) (1119/1)

7873 23/11/94 -9.00 960 450 34.0 -9 342 0 57.0 20.3 42.4 -9.00 0.53 104.0 10.7 18.0 32.0 -9.00 -9.00 56 31 DGS 8.06 793 237 1 7873 24/11/94 -9.00 735 -9 -9.0 271 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 FINAL DGS -9.00 735 -9 1 7874 25/11/94 -9.00 649 360 -9.0 252 293 0 35.0 18.2 1.7 -9.00 1.20 63.0 8.9 32.0 22.0 -9.00 -9.00 52 31 DGS 7.51 615 -9 1 7875 26/11/94 -9.00 851 524 -9.0 -9 388 0 78.0 21.3 -9.0 -9.00 0.48 92.0 12.8 44.0 29.0 -9.00 -9.00 36 31 DGS 7.79 918 -9 1 7875 28/11/94 -9.00 1030 620 -9.0 -9 354 0 99.0 24.8 57.3 -9.00 0.41 130.0 8.0 46.0 24.0 -9.00 -9.00 55 FINAL DGS 7.77 1020 -9 1 7880 17/03/95 0.00 20000 36000 -9.0 -9 688 012837.0 8072.0 -9.0 -9.00 -9.00 15000.0 150.0 420.0 350.0 -9.00 -9.00 12 93 DGS 7.43 45700 -9 3 7880 21/03/95 8.00 20000 35200 -9.0 -9 516 o 14056.0 8680.3 -9.0 -9.00 -9.00 12500.0 280.0 380.0 320.0 -9.00 -9.00 10 385 DGS 7.49 42600 -9 4 7880 27/03/95 9.00 20000 -9 -9.0 -9 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 FINAL DGS -9.00 -9 -9 8 7883 24/03/95 9.00 20000 50000 -9.0 -9 2395 56 25160.0 4438.8 -9.0 -9.00 -9.00 19000.0 240.0 15.0 39.0 -9.00 -9.00 16 87 DGS 8.20 59800 -9 3 7883 28/03/95 9.00 20000 53500 -9.0 -9 1939 673 17971.0 6904.8 -9.0 -9.00 -9.00 21500.0 260.0 2.0 3.0 -9.00 -9.00 10 FINAL DGS 8.47 69200 -9 3 7884 24/03/95 7.00 -9 460 -9.0 349 259 0 27.0 26.1 58.3 -9.00 1.12 54.0 24.5 30.0 19.0 -9.00 -9.00 48 17 DGS 7.95 652 -9 1 7885 08/04/95 -9.00 20000 14000 -9.0 -9 274 45 7060.0 3045.5 -9.0 -9.00 -9.00 6200.0 48.0 82.0 72.0 -9.00 -9.00 4 106 DGS 8.20 24100 -9 4

BH_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 804 N03 N02 F Na K Ca Kg Fe MD SI02 IISL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

1885 22/04/95 -9.00 20000 19000 -9.0 292 290 o 3745.0 8535.2 -9.0 -9.00 -9.00 5600.0 105.0 110.0 106.0 -9.00 -9.00 5 395 DGS 8.12 23010 -9 4 7885 14/05/95 7.91 18920 15400 -9.0 214 215 o 5437.0 4706.0 -9.0 -9.00 -9.00 5800.0 190.0 220.0 54.0 -9.00 -9.00 12 FINAL DGS 7.82 21900 -9 8 7886 30/03/95 9.00 20000 20200 -9.0 -9 342 o 6386.0 6140.3 -9.0 -9.00 -9.00 6600.0 510.0 120.0 96.0 -9.00 -9.00 1 123 DGS 7.49 25800 -9 4 7886 31/03/95 9.00 20000 18900 -9.0 -9 342 o 6226.0 5832.7 -9.0 -9.00 -9.00 6800.0 110.0 120.0 72.0 -9.00 -9.00 5 FINAL DGS 7.97 25200 -9 4 7889 06/04/95 7.00 -9 406 -9.0 305 257 0 31.0 24.5 58.7 -9.00 1.05 58.0 6.4 45.0 16.0 -9.00 -9.00 59 18.5 DGS 7.77 648 -9 1 7889 07/04/95 7.00 -9 460 -9.0 297 298 0 35.0 22.0 61.4 7.50 1.17 70.0 8.4 50.0 15.0 -9.00 -9.00 55 FINAL DGS 7.79 728 -9 1 7889 15/05/95 -9.00 -9 400 -9.0 -9 300 0 62.5 18.4 50.5 -9.00 -9.00 55.0 5.0 68.0 18.2 0.05 -9.00 -9 STU lies 7.36 687 -9 1 7889 15/05/95 -9.00 -9 589 -9.0 -9 297 0 35.0 17.5 43.8 -9.00 -9.00 54.0 4.0 68.0 17.5 0.05 -9.00 -9 STP_5 WCS 7.46 679 -9 1 7889 23/05/95 -9.00 -9 600 -9.0 -9 287 0 87.5 17.8 39.5 -9.00 -9.00 60.0 7.0 68.8 17.5 0.05 -9.00 -9 STEP_1 lies 7.69 686 -9 1 7889 24/05/95 7.54 668 400 62.0 320 292 0 42.0 17.5 44.2 -9.00 -9.00 59.0 9.0 68.4 18.2 0.05 -9.00 -9 STEP_5 lies 7.34 702 -9 1 7889 25/05/95 7.19 660 400 71.0 322 302 0 40.7 16.9 43.8 -9.00 -9.00 58.0 8.0 69.6 17.0 0.05 -9.00 -9 eR_24 WCS 7.25 693 -9 1 7889 26/05/95 7.26 707 500 49.0 308 306 0 39.7 16.5 45.3 -9.00 -9.00 60.0 10.0 70.0 17.3 0.05 -9.00 -9 eR38 lies 7.30 704 -9 1

BH_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk RC03 C03 Cl 804 N03 002 F Na K Ca Kg Fe !In Si02 IISL Data Source Lab-pH Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

7892 29/04/95 8.00 3770 1030 -9.0 502 292 27 265.0 185.7 25.7 -9.00 -9.00 330.0 26.0 8.0 15.0 -9.00 -9.00 4 108 DGS 8.33 1820 -9 3 7892 03/05/95 8.00 2560 -9 -9.0 494 -9 -9 -9.0 -9.0 -9.0 -9.00 -9.00 -9.0 -9.0 -9.0 -9.0 -9.00 -9.00 -9 FINAL DGS -9.00 2560 -9 3 7892 18/05/95 7.52 2520 1600 32.0 566 586 0 429.6 237.6 40.6 -9.00 -9.00 380.0 20.0 22.4 24.3 0.03 -9.00 -9 STEU lies 7.08 2910 -9 3 7892 19/05/95 7.98 2370 1600 55.0 575 570 0 429.4 239.6 40.6 -9.00 -9.00 359.0 21.0 0.0 23.8 0.05 -9.00 -9 STEP_6 lies 7.03 2880 -9 :> 7892 20/05/95 7.84 2430 1600 49.0 547 578 0 469.9 235.5 39.1 -9.00 -9.00 348.0 20.0 20.0 24.3 0.07 -9.00 -9

eR_24 wes 7.19 2930 -9 3 7892 21/05/95 8.16 2460 1600 44.0 556 578 0 462.4 228.6 41.4 -9.00 -9.00 344.0 23.0 20.2 24.2 0.04 -9.00 -9

eR_48 lies 7.07 2890 -9

3 7893 05/05/95 8.86 6180 -9 -9.0 520 475 58 1248.0 917.4 -9.0 -9.00 -9.00 1400.0 87.5 38.0 63.0 -9.00 -9.00 7 112 DGS 8.20 6680 -9 3 7893 06/05/95 -9.00 5570 3600 -9.0 -9 498 55 1399.0 471.8 -9.0 -9.00 -9.00 1250.0 72.5 28.0 35.0 -9.00 -9.00 6 FINAL DGS 8.29 6030 -9 3 7918 08/05/95 8.16 627 360 -9.0 306 256 0 32.0 20.1 29.0 -9.00 1.76 -9.0 8.1 48.0 38.0 -9.00 -9.00 38 34 DGS 7.99 634 -9 1 7918 09/05/95 -9.00 590 400 -9.0 -9 240 17 28.0 18.1 31.1 -9.00 1.47 74.0 8.6 33.0 16.0 -9.00 -9.00 44 FINAL DGS 8.20 355 -9 1 7921 13/05/95 10.50 128000 114600 -9.0 -9 7324266653958.312913.7 3.4 -9.00 -9.00 15000.0 ••••• 0.0 5.8 0.16 -9.00 -9 14 lies 9.21 125000 -9 1 7923 16/05/95 7.98 561 420 67.0 263 256 0 23.2 17.9 25.0 -9.00 -9.00 39.0 19.0 41.6 25.8 0.03 -9.00 -9 36 lies 7.51 576 -9 1

BH_oo Date Fld-pH Fld_EC TDS Fld_DO(') Fld_Alk HOO3 C03 Cl 304 003 002 F Na K Ca lI<J Fe MD S102 WSL Data Source Lab-pH LaUC Eh (mV) Aquifer (US/an) (mg/l) (mg/l)

7925 18/05/95 7.88 11480 8000 48.0 423 370 o 4173.7 978.7 11.7 -9.00 -9.00 1500.0 140.0 375.8 275.5 0.06 -9.00 -9 88 wes 7.13 15160 -9 3 7925 19/05/95 7.93 10500 8200 39.0 417 370 o 4573.6 1086.3 12.3 -9.00 -9.00 1580.0 120.0 362.8 301.8 0.07 -9.00 -9 FINAL wes 6.83 9400 -9 3 7927 26/05/95 7.00 8140 4800 -9.0 674 548 25 3174.0 1147.2 17.2 -9.00 -9.00 1600.0 180.0 10.4 14.1 0.06 -9.00 -9 389 \'Ies 8.69 7640 187 5 7927 01/06/95 7.50 10100 6200 -9.0 -9 806 30 3274.0 1289.3 7.2 -9.00 -9.00 2000.0 220.0 15.6 16.1 0.04 -9.00 -9 412 lies 8.32 8520 -9 5 7928 23/05/95 8.34 -9 22600 -9.0 1823 1699 o 11821.3 1880.2 25.9 -9.00 -9.00 6400.0 200.0 28.8 95.8 0.05 -9.00 -9 100 lies 8.04 44000 -9 3 7928 23/05/95 -9.00 -9 26800 -9.0 -9 1645 o 13570.8 4653.8 23.8 -9.00 -9.00 7800.0 240.0 34.0 124.3 0.07 -9.00 -9 FINAL \'Ies 8.03 51000 -9 3 7947 26/05/95 7.87 2770 1800 -9.0 306 299 0 730.0 28.4 51.1 -9.00 -9.00 220.0 18.0 169.6 101.2 0.09 -9.00 -9 FINAL \'Ies 7.22 3160 -9 1 Z4676 25/07/94 7.17 11250 4636 -9.0 728 488 o 2340.0 532.7 -9.0 -9.00 -9.00 1750.0 27.5 53.0 62.0 -9.00 -9.00 14

DGS 6.66 9070 -9 8 Z5316 18/06/86 -9.00 -9 27628 -9.0 -9 878 o 10210.0 5500.0 0.0 -9.00 0.54 13500.0 28.0 68.0 170.0 0.01 0.01 -9

7.48 63464 -9 8 Z5316 18/06/86 -9.00 -9 27388 -9.0 -9 859 o 9855.0 4800.0 0.0 -9.00 0.58 13100.0 31.0 84.0 168.0 0.35 0.01 -9

7.43 41234 -9 8 Z5523 02/05/87 -9.00 -9 21108 -9.0 -9 841 o 8662.0 1400.0 0.5 -9.00 15.00 8520.0 50.0 4.0 36.0 0.30 0.10 -9

9.70 38121 -9 8 Z5523 27/07/94 9.43 18630 13600 -9.0 3561 12441188 4787.0 1500.2 -9.0 -9.00 -9.00 5050.0 212.5 1.0 1.0 -9.00 -9.00 22

DGS 8.51 20700 -9 8

BB_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 804 N03 002 F Na K Ca Kg Fe Mn 5102 IISL Data Source Lab-pB Lab_EC Eh (mV) Aquifer (US/cm) (mg/l) (mg/l)

Z5596 14/01/94 6.94 981 620 -9.0 309 311 0 17 .0 24.6 102.2 -9.00 0.58 80.0 10.0 90.0 20.0 -9.00 -9.00 66 DGS 6.12 1000 -9

8 Z1257 04/08/94 1.60 11450 11400 -9.0 1501 1581 o 5561.0 324.1 -9.0 -9.00 -9.00 4350.0 130.0 20.0 31.0 -9.00 -9.00 14

DGS 1.04 18000 -9 3 Z7258 26/01/94 6.99 20000 35820 -9.0 831 181 o 11588.0 6181.5 -9.0 -9.00 -9.00 13400.0 210.0 220.0 245.0 -9.00 -9.00 22

DGS 6.40 49100 -9 3 Z7350 25/01/94 7.20 2310 1216 -9.0 661 659 0 284.0 121.1 28.1 -9.00 1.19 415.0 33.5 26.0 23.0 -9.00 -9.00 22

DGS 1.01 2250 -9 3

BR_NO Date Fld-pH flOC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl S04 N03 002 F Na K Ca Hq Fe MD S102 IISL Data Source Lab-pH Lab_EC Eh (roV)

(US/an) (mg/l) (mg/l)

11106 04/08/94 6.98 759 480 56.0 315 317 0 41.0 15.0 55.9 -9.00 0.96 48.0 8.6 70.0 25.0 -9.00 -9.00 70 DGS 6.81 760 172

11114 03/08/94 6.94 2530 1458 -9.0 378 439 0 530.0 49.9 185.6 0.00 0.78 335.0 25.5 132.0 48.0 0.00 0.00 65 DGS 6.71 2780 -9

11116 04/08/94 7.13 2030 1208 45.0 381 366 0 411.0 52.2 89.9 -9.00 1.12 315.0 35.0 58.0 30.0 -9.00 -9.00 71 DGS 6.88 2110 199

11111 04/08/94 7.53 1801 1040 55.0 439 444 0 272.0 43.8 84.7 -9.00 1.03 275.0 27.5 50.0 28.0 -9.00 -9.00 71 DGS 7.06 1800 149

11119 03/08/94 7.28 937 600 -9.0 452 481 0 60.0 20.5 13.4 -9.00 1.23 94.0 11.5 78.0 21.0 -9.00 -9.00 70 DGS 6.90 965 -9

\"/120 03/08/94 7.71 18630 12600 -9.0 1226 1196 o 6383.0 669.9 -9.0 -9.00 -9.00 4600.0 175.0 70.0 67.0 -9.00 -9.00 58 DGS 7.04 19200 -9

\/125 05/08/94 7.27 610 400 -9.0 248 266 0 23.0 11.3 49.2 -9.00 0.57 18.0 6.9 81.0 15.0 -9.00 -9.00 66 DGS 7.44 615 -9

11126 05/08/94 7.61 3340 1908 -9.0 398 407 0 613.0 96.0 242.5 -9.00 1.45 510.0 86.0 65.0 36.0 -9.00 -9.00 73 DGS 7.49 3270 -9

11138 09/08/94 7.53 950 520 -9.0 324 290 0 78.0 13.9 80.5 -9.00 0.60 56.0 6.0 80.0 30.0 -9.00 -9.00 42 DGS 7.49 890 145

W159 17/08/94 7.81 2125 1460 -9.0 404 415 0 426.0 148.2 86.1 -9.00 0.98 315.0 38.0 96.0 36.0 -9.00 -9.00 78 DGS 6.95 2300 219

W34 15/07/94 7.32 916 700 -9.0 318 337 0 50.0 12.3 202.1 -9.00 0.39 82.0 11.0 88.0 21.0 -9.00 -9.00 68 DGS 7.00 989 -9

115 12/07/94 7.02 867 592 -9.0 355 342 0 48.0 10.5 123.5 -9.00 0.67 42.0 9.8 92.0 31.0 -9.00 -9.00 82 DGS 6.64 919 -9

BH_NO Date Fld-pH Fld_EC TDS Fld_DO(%) Fld_Alk HC03 C03 Cl 304 N03 002 F Na K Ca Kg Fe Mn S102 WSL Data Source Lab-pH Lab_EC Eh (mV)

(us/cm) (mg/l) (mg/l)

1159 03/08/94 7.09 846 600 -9.0 321 293 0 92.0 50.8 44.9 -9.00 0.88 74.0 12.6 73.0 23.0 -9.00 -9.00 78 DGS 6.99 935 -9

W6 12/07/94 7.43 746 580 -9.0 290 293 0 58.0 58.2 68.7 -9.00 0.74 62.0 11.2 69.0 23.0 -9.00 -9.00 81 DGS 6.92 868 -9

W69 08/08/94 -9.00 19500 13300 -9.0 -9 1903 648 5674.0 694.6 -9.0 -9.00 -9.00 4950.0 225.0 6.0 2.0 -9.00 -9.00 41 DGS 8.75 19800 -9

W80 02/08/94 9.03 14440 9600 -9.0 3020 1854 708 3901.0 213.7 -9.0 -9.00 -9.00 3750.0 280.0 1.0 2.0 -9.00 -9.00 20 DGS 8.70 14900 -9

W90 29/07/94 7.26 830 500 -9.0 283 317 0 43.0 18.7 54.6 -9.00 0.95 54.0 5.8 70.0 23.0 -9.00 -9.00 75 DGS 6.81 784 -9

1"194 17 /08/94 7.98 18880 11200 -9.0 1020 891 o 5759.0 768.6 -9.0 -9.00 -9.00 4200.0 87.5 45.0 38.0 -9.00 -9.00 34 DGS 7.63 17300 207

W96 05/08/94 7.24 727 408 -9.0 264 222 0 34.0 29.3 55.6 -9.00 0.68 46.0 9.6 54.0 13.0 -9.00 -9.00 56 DGS 7.52 630 -9


APPENDIX B

Comparison of GRES II and DGS Data


WELLFlELD CONSULTING SERVICES P,O.Box 1502 Gaborone, Botswana

BH No Data Source Date pH SEC C03 HC03 Cl S04 N03 F Na K Ca Mg uS/cm mgll mg/I mg/I mgll mgll mg/I mg/l mgll mgll mgll

473 DGS 14/07/94 6.72 1800 0 364.0 287.0 40.9 138.4 0.5 215.0 5.0 102.0 32.0 473 GRES 14107194 7.67 1799 0 401.0 279.3 54.4 135.2 -9.0 194.9 5.9 115.0 33.8

4248 DGS 12/08/94 7.50 3080 0 683.0 645.0 236.6 22.8 5.8 750.0 23.0 28.0 18.0 4248 GRES 12/08194 8.10 4224 41 860.0 797.6 324.7 28.8 -9.0 855.2 21.2 37.3 22.9 4251 DGS 25/07/94 7.03 8180 0 1049.0 1759.0 831.9 -9.0 -9.0 1800.0 37.5 30.0 36.0 4251 GRES 25/07/94 8.21 7684 29 1037.0 1630.6 814.6 44.7 -9.0 1397.7 29.8 22.7 26.0 4516 DGS 04/08/94 7.08 903 0 303.0 58.0 29.6 93.9 0.8 62.0 5.4 76.0 30.0 4516 GRES 04/08/94 7.81 898 0 332.0 53.9 18.7 146.9 -9.0 51.0 7.2 79.4 31.4 5128 DGS 21/08/94 7.83 165400 0 8540.'0 85104.0 10994.3 -9.0 -9.0 62000.0 500.0 1.0 -9.0 5128 GRES 21108/94 9.09 128200 1719 2404.0 79085.4 11047.1 6.5 -9.0 50505.7 574.9 0.2 0.1 5283 DGS 04/08/94 6.87 867 0 281.0 87.0 15.0 57.2 0.5 80.0 3.4 61.0 19.0 5283 GRES 04/08/94 6.99 843 0 300.0 79.8 38.1 79.4 -9.0 74.9 3.9 63.3 19.5 5448 DGS 31/07/94 6.81 759 0 305.0 48.0 19.6 43.6 0.6 70.0 6.5 64.0 16.0 5448 GRES 31107194 7.76 733 0 331.0 45.0 22.5 95.5 -9.0 61.6 3.2 68.5 15.7 5947 DGS 03/08/94 6.88 2110 0 468.0 380.0 45.3 73.9 0.9 315.0 23.5 76.0 28.0 5947 GRES 03/08/94 7.69 1926 0 505.0 280.0 53.0 80.6 -9.0 221.8 9.0 86.2 31.1 5948 DGS 03/08/94 6.65 1450 0 415.0 201.0 32.2 71.7 0.7 148.0 5.2 94.0 30.0 5948 GRES 03/08/94 7.47 1352 0 459.0 192.1 37.4 81.8 -9.0 131.7 5.6 103.4 30.9 6043 DGS 12/08/94 6.69 12500 0 49.0 2312.0 3470.5 -9.0 -9.0 2250.0 90.0 580.0 138.0 6043 GRES 12/08/94 7.57 11430 0 66.0 2290.0 3525.5 0.6 -9.0 1908.0 14.7 629.3 129.3 6046 DGS 03/08/94 6.88 1830 0 4680 272.0 55.4 58.9 0.7 290.0 11.5 56.0 18.0 6046 GRES 03/08/94 7.46 1584 0 498.0 101.4 60.6 89.3 -9.0 192.2 9.3 75.8 21.3 6088 DGS 04/08/94 6.83 1240 0 432.0 116.0 36.7 80.6 0.5 158.0 5.2 69.0 19.0 6088 GRES 04/08/94 7.20 1155 0 441.0 109.4 41.6 116.6 -9.0 147.4 5.3 70.9 18.9 6482 DGS 09/08/94 7.50 834 0 288.0 50.0 17.2 89.8 0.4 68.0 4.2 75.0 16.0 6482 GRES 09/08/94 7.94 828 9 274.0 43.6 18.3 155.6 -9.0 58.9 3.9 80.2 17.6 6484 DGS 09/08/94 7.26 843 0 339.0 41.0 13.7 88.5 0.5 52.0 4.0 88.0 20.0 6484 GRES 09108194 7.85 833 8 329.0 33.4 13.8 141.4 -9.0 43.9 4.2 96.2 21.2

24676 DGS 25/07/94 6.66 9070 0 488.0 2340.0 532.7 -9.0 -9.0 1750.0 27.5 53.0 62.0 24676 GRES 25/07/94 8.11 11920 24 714.0 3268.3 928.9 78.1 -9.0 1059.8 17.9 33.6 40.1 25523 DGS 27107194 8.51 20700 1188 1244.0 4787.0 1500.2 -9.0 -9.0 5050.0 212.5 1.0 1.0 25523 GRES 27/07/94 9.56 21530 651 2203.0 5423.6 2113.4 1.9 -9.0 5149.4 97.4 0.1 -9.0 25596 DGS 14/07/94 6.72 1000 0 317.0 77.0 24.6 102.2 0.6 80.0 10.0 90.0 20.0 25596 GRES 14/07/94 6.65 1010 0 358.0 720 22.9 151.9 -9.0 69.7 4.3 107.8 22.2 27257 DGS 04/08/94 7.04 18000 0 1581.0 5567.0 324.7 -9.0 -9.0 4350.0 130.0 20.0 31.0 27257 GRES 04/08/94 8.22 18640 68 1428.0 5423.6 1767.5 58.1 -9.0 4160.9 127.1 18.2 28.2

BH No Data Source Date pH SEC C03 HC03 Cl S04 N03 F Na K Ca Mg uS/cm mg/J mg/I mg/l mg/l mg/l mg/I mg/I mg/l mg/I mg/l

Z7258 DGS 26/07/94 6.40 49700 0 781.0 17588.0 6781.5 -9.0 -9.0 13400.0 210.0 220.0 245.0 Z7258 GRES 26/07/94 7.94 45900 26 824.0 15987.2 8251.7 5.5 -9.0 12183.9 152.1 206.0 265.0 Z7350 DGS 25/07/94 7.07 2250 0 659.0 284.0 121. 7 28.1 1.2 415.0 33.5 26.0 23.0 Z7350 GRES 25/07/94 8.46 2203 23 647.0 291.7 147.0 33.4 -9.0 420.7 4.7 26.2 22.9 W5 DGS 12/07/94 6.64 919 0 342.0 48.0 10.5 123.5 0.7 42.0 9.8 92.0 31.0 W5 GRES 12/07/94 7.79 893 II 321.0 44.7 12.4 143.8 -9.0 12.7 8.8 98.2 32.6 W6 DGS 12/07/94 6.92 868 0 293.0 58.0 58.2 68.7 0.7 62.0 11.2 69.0 23.0 W6 GRES 12/07/94 7.86 793 0 329.0 55.3 19.1 83.1 -9.0 49.4 5.4 71.3 22.8 W34 DGS 15/07194 7.00 989 0 337.0 50.0 12.3 202.1 0.4 82.0 11.0 88.0 21.0 W34 GRES 15/07/94 7.71 933 0 375.0 49.6 18.3 148.2 -9.0 69.0 4.6 103.0 21.0 W80 DGS 02/08194 8.70 14900 708 1854.0 3901.0 213.7 -9.0 -9.0 3750.0 280.0 1.0 2.0 W80 GRES 02/08/94 9.19 15020 327 2178.0 4218.4 237.3 205.8 -9.0 3540.2 238.6 0.0 0.3 W90 DGS 29/07/94 6.81 784 0 317.0 43.0 18.7 54.6 1.0 54.0 5.8 70.0 23.0 W90 GRES 29/07/94 7.87 751 0 340.0 39.3 16.0 81.2 -9.0 40.2 6.5 73.7 23.3 W96 DGS 05/08/94 7.52 630 0 222.0 34.0 29.3 55.6 0.7 46.0 9.6 54.0 13.0 W96 GRES 05/08/94 7.84 748 9 285.0 35.0 15.9 106.0 -9.0 52.0 4.7 76.2 16.0 WlO6 DGS 04/08/94 6.81 760 0 317.0 41.0 15.0 55.9 1.0 48.0 8.6 70.0 25.0 W\06 GRES 04/08/94 7.91 758 8 312.0 37.2 18.5 83.7 -9.0 38.6 9.3 76.2 26.3 WI14 DGS 03/08/94 6.71 2780 0 439.0 530.0 49.9 185.6 0.8 335.0 25.5 132.0 48.0 WI14 GRES 03/08/94 7.82 2507 13 425.0 485.6 53.9 212.0 -9.0 264.4 8.6 137.9 48.6 W1l6 DGS 04/08/94 6.88 2110 0 366.0 411.0 52.2 89.9 l.l 315.0 35.0 58.0 30.0 WI16 GRES 04/08/94 7.91 2078 10 389.0 314.1 61.5 156.2 -9.0 252.9 16.9 63.3 29.7 W1l7 DGS 04/08194 7.06 1800 0 444.0 272.0 43.8 84.7 1.0 275.0 27.5 50.0 28.0 W1l7 GRES 04/08/94 7.87 1771 0 486.0 270.1 54.7 135.2 -9.0 259.8 12.0 47.3 27.7 W1l9 DGS 03/08/94 6.90 965 0 481.0 60.0 20.5 13.4 1.2 94.0 11.5 78.0 21.0 WI20 DGS 03/08/94 7.04 19200 0 1196.0 6383.0 669.9 -9.0 -9.0 4600.0 175.0 70.0 67.0 W125 DGS 05/08/94 7.44 615 0 266.0 23.0 11.3 49.2 0.6 18.0 6.9 81.0 15.0 WI25 GRES 05/08/94 7.80 616 0 266.0 23.0 13.9 82.5 -9.0 15.5 6.2 85.0 15.4 W126 DGS 05/08/94 7.49 3270 0 407.0 6\3.0 96.0 242.5 1.5 510.0 86.0 65.0 36.0 WI26 GRES 05/08/94 7.90 3248 6 419.0 577.8 127.8 363.3 -9.0 505.7 84.9 64.5 36.5 WI38 DGS 09/08/94 7.49 890 0 290.0 78.0 13.9 80.5 0.6 56.0 6.0 80.0 30.0 WI38 GRES 09/08/94 7.80 978 0 291.0 70.9 17.8 147.6 -9.0 49.2 6.7 93.4 34.8 WI59 DGS 17/08/94 6.95 2300 0 415.0 426.0 148.2 86.1 1.0 315.0 38.0 96.0 36.0

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