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~~m~flllll]llliiljl~(II~~llliy 7802688191

Bulletin 46 Hydraulic Conductivity and Transmissivity

of a Water - Table Aquifer in the Boro River System, Okavango Delta

by

O. Obakeng and

A. Gicskc

December 1997

Price: P15.00

Hydraulic Conductivity and Transmissivity of a Water-Table Aquifer in the Boro River System, Okavango Delta.

Table of Contents

1 General Introduction

1.1 1.2 1.3

1.4

Objective of the study Study Areas Previous Studies of the Delta's Hydrology and Water Chemistry Field and Laboratory activities

2 Field methods

2.1 Installation and construction of piezometers 2.2 Survey of the ORC site and piezometers 2.3 Water level observations

2.3.1 Surface water levels 2.3.2 Groundwater levels

2.4 Well test Analysis 2.4.1 Introduction 2.4.2 Methods 2.4.3 Results and Discussions

A. Jacobjrheis analysis B. Zangar method C. Moench method

2.4.4 Comparison of results

3 Laboratory methods

page

1 1

5 5

6 11 15 15 17 20 20 23 27

34

36

3.1 Introduction 36 3.2 Estimating hydraulic conductivity from grain size 36

distributions 3.3 Porosity and bulk density methods 39 3.4 Permeameter tests

3.4.1 Constant head permeameter 39 3.4.2 Falling head permeameter 40

3.5 Results grain size distributions 41 3.5.1 Introduction 41 3.5.2 Field results 42 3.5.3 Comparison UB and GS analysis with particle size analysis

by the Soils Laboratory of the Ministry of Agriculture 45 3.6 Porosity and bulk density results 46 3.7 Relation between conductivities determined by the perm ea meter

method and. grain size analysis 47

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3.8 Applications 3.8.1 The Shashe Wellfield upper unconfined aquifer 3.8.2 Beacon Island inlet channel 3.8.3 Transect on the flood plain of the ORC site

4 Major ion chemistry

4.1 4.2 4.3

5 Conclusions

Introduction Materials and methods Results and. discussion 4.3.1 Analysis of data 4.3.2 Hydrochemical trends

6 Acknowledgments

7 References

List of figures

Fig. 1 Map of the Okavango Delta showing Beacon Island and ORC site.

Fig. 2 Simplified location map of ORC site on Chiefs Island, showing piezometer sites.

Fig. 3 Construction of piezometer 2. Silts and fine sand have entered through the slots, thus reducing the effective piezometer length.

Fig. 4 Construction of piezometer A. Pantihose (20 decitex) works as an effective geotextile.

Fig. 5 Map showing ORC weir site and benchmark position. Fig. 6 Gradient of main inlet channel around the weir site. Fig. 7 Cross-section of the inlet channel at the weir site

showing construction of the weir. Fig. 8 Transect on the main flood plain (see Fig. 2), showing

location of piezometers. Note the ridge between channel and floodplain. Flooding occurs when the level in the channel rises above the bank at a spot where the bank level is lowest.

Fig. 9 Transect along the main eastern branch through the pan to the forested ridge. Flooding of this eastern branch starts only when the water level in the northern channel with associated flood plains has reached a threshold level.

Fig. 10 Rise in Boro River water levels near the Camp Site on Half Moon Island (period June 13 - July 8, 1997).

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51 51 54 55

61 61 62 62 62

64

66

67

page

2

4

10

10 11 12

12

13

13

15

Fig. 11 Rising water level at the weir, relative to benchmark. 16 Fig. 12 Rising water level in main northern channel (see Figs.

2 and 8). 16 Fig. 13 Hydrograph of piezometer 2 (installed in April 1997). 18

Water level receded below the sediment collected in the pipe, probably not far. Recession rate can only be estimated ("" 2 m/yr). The infiltration rate (rise of the water table) was in the order of 1.5 m/day.

Fig. 14 Rise of groundwater levels in piezometers C, D and E (close to the weir site) during the fieldwork period is caused by the gradual rise of surface water in the inlet channel (see Fig. 11). 18

Fig. 15 Hydrograph of piezometer F on the inlet point of the large pan in the eastern catchment (Fig. 2). This hydrograph is still far from the advancing floods on July 8, 1997, and therefore shows natural recession (::::1.4 m/yr) because of evapotranspiration (see also Fig. 9 which shows the position of F on the transect through the pan). 19

Fig. 16 Aerial photograph of the catchment (28 August, 1991), 91/1, Okavango Run 21, 255 (1:50000). Compare the extent of the flooding with Fig. 2. The pan is over-flowing to the right. Half Moon Island is completely surrounded by water. The Boro River is clearly visible in the bottom left corner. 19

Fig. 17 Pumping test site CDE near the weir, showing pumped hole C and the two observation holes D and E. Two tests were conducted at this site (see Plate 12). 22

Fig. 18 Construction of the slotted pipes, showing distribution and size of slots. 22

Fig. 19 Type curves for well testing in water-table aquifers (Neuman, 1972). 23

Fig. 20 Parameter definitions in the Zangar method (see Eqn 4). 25

Fig. 21 Geometric factor C as a function of h/r (Eqn. 4). 25 Fig. 22 Parameters for the pumped well and the observation

holes in the Moench (1996) method. 26 Fig. 23 Drawdown plot of constant rate test at site CDE. C is

the pumped hole. D and E are observation wells (see Plate 12 and Fig. 17). The observations at early times are probably influenced by wellbore storage, while the flattening above 100 min is caused by the phreatic nature of the aquifer. 29

Fig. 24 Residual drawdown plot of recovery test at site CDE. Piezometer D, second test. 29

Fig. 25 Definition of parameters for the Zangar method as applied in this report (see also Fig. 20). 30

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Fig. 26 Illustration of a type curve for an observation hole, partially penetrating an unconfined aquifer. The dashed curves show the Theis curves for early (S) and late times (Sy). The plotted points are those for CRT D2 with y=3 and T=32.1 m2/day. 32

Fig. 27 Illustration of the effect of changes in y on the transmissivity values. See well tests (9,10), (12,13) and (15,16) in Table 4. 32

Fig. 28 Illustration of piezometer and well screen data required by Aquifer Test (1997). 35

Fig. 29 Composite plot of drawdowns in piezometers D and E (site CDE, test 2, see Fig. 17, page 22, and Fig. 28 above). 35

Fig. 30 Correction factors for estimating hydraulic conductivity of sand from grain size distribution expressed in specific surface (U) (ILRI, 1974, Boonstra and De Ridder, 1981). 38

Fig. 31 Constant-head permeameter. 40 Fig. 32 Falling-head permeameter. 40 Fig. 33 Particle size analysis, showing cumulative curves for

clay, silty loams and medium sand. Three different classification systems are shown on the bar below the figure. In all cases the clay particle size boundary

I is 2 /illl. 41 ISSS: International Society of Soil Science MIT: Massachusetts Institute of Technology USDA: United States Department of Agriculture BSI: British Standards Institution

Fig. 34 Cumulative distribution curves ORC site (33 samples, UB analysis). 42

Fig. 35 Cumulative distribution curves ORC site (29 samples, GS analysis). 42

Fig. 36 Cumulative distribution curves for the Beacon Island inlet area. The coarse material was found about 4 to

r.: 5 m below the inlet point. Grain size distributions

I of this sand are similar to those encountered in the

! Shashe River. 43

i Fig. 37 Cumulative distribution curves of the top 16 samples

! collected from Borehole PHI (Gabaake et aI., 1993). A sample was taken at intervals of 1 m. 44

Fig. 38 The figure shows the two extreme cumulative distri-bution curves of sands encountered in the Delta thus far. 44

Fig. 39 Comparison of the particle size analysis by UB (oven-drying and then sieving) with the results of the Soils Lab (Sebele) where clay content was determined by hydrometer analysis. The dry sieving method obscures the presence of fines and clays. 45

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Fig. 40 Cumulative distribution curves for a medium sand (Beacon Island, depth 4.70 m). The two laboratory procedures yield the same results. 46

Fig. 41 Plot of hydraulic conductivities from permeameter tests against those determined by grain size analysis. 47

Fig. 42 Final correlation between kJ,erm and ~sa using a proportionality factor of 20000 (Eqn. 11). 48

Fig. 43 Hydraulic conductivity derived from grain size distributions, plotted against depth for pilot borehole PHI (Shashe Wellfield, Maun). 52

Fig. 44 Hydraulic conductivity as a function of depth (Beacon Island, inlet channel). The high hydraulic conductivity is caused by layers of uniform medium sand in a paliieo-channel. 54

Fig. 45 Conductivity as a function of depth for piezometer 1 (forest edge). 59

Fig. 46 Conductivity as a function of depth for piezometers 2 and A (A is 5 m south of 2 along the transect. Three different sets of values are shown: the ~a from the GS analysis, the ~sa from the VB analysis and the kJ,erm from the VB permeameter analysis. The GS ana-lysis probably leads to overestimation because of different class intervals. 59

Fig. 47 Conductivity as a function of depth for piezometer 3 (in the main channel). 60

Fig. 48 Conductivity as a function of depth for piezometer 4 (along the main track on Chiefs Island). 60

Fig. 49 Comparison of the cation analysis by the GS and VB Chemical Laboratories. The GS samples were non-acidified (1000 ml samples), while the VB samples were pre-acidified with 1.75 ml of 55% nitric acid (250 ml samples). Note the discrepancy for Ca2+. 62

Fig. 50 Piper diagram of major anion and cation concentrations of the surface water samples (circles) and groundwater samples (squares). The concentrations in meq/I can be found in Table 15. 63

Fig. 51 EC ({S/cm) plotted against TDS (ppm). Note the increase in EC and TDS between surface water and groundwater. 64

Fig. 52 Plot of the major anion and cation concentrations (meq/l) against the ionic species. The top diagram shows the concentrations in groundwater, while the bottom diagram shows those in surface water in the area. 65

Cv)

,~ •. , I

f! j' ~ i j,

!

List of tables

Table 1 Summary of the experimental small scale pumping tests Table 2 Results Jacob/Theis manual analysis (drawdown plots,

App. D, pp. 10-16). Table 3 Zangar method input data and results (Zangar, 1953, ILRI,

1974). Table 4 Results of well test interpretation with the Moench method

for unconfined aquifers with partially penetrating boreholes.

Table 5 Comparison of well testing results Table 6 Classification of sandy materials, grain size limits,

and corresponding specific surface value (U) (lLRI, 1974) Table 7 Results of porosity and bulk density determination. Table 8 Calculation of hydraulic conductivities through Eqn. 7

(samples 32-52). Table 9 Calculation of hydraulic conductivities through Eqn. 7

(samples 53-72). Table 10 Calculation of hydraulic conductivities for bore hole PHI

(top 16 m). The data for this borehole can be found in

Table 11 Gabaake et aJ. (1993). ~sa was calculated by Eqn. 11. Calculation of conductivities for Beacon Island inlet point.

Table 12 Calculation of conductivities for sites 1 (forest edge, piez 1), 7 (plain, piez 2), 14 (main channel, piez 3) and 17 (road, piez 4) of the main flood plain transect (see Fig. 2).

Table 13 Calculation of conductivities for samples 73-78 on the main flood plain transect (Analysis by GS).

Table 14 Calculated and measured conductil~ties for piezometers 1, 2, 3 and 4 on the flood plain transect.

Table 15 Major ion composition of surface water and groundwater at the ORC site (units meq/l).

List of plates

Plate 1 Boro River with Chiefs Island in the background. Plate 2 Inlet channel from the Boro River into the floodplains

(ORC weir site). Plate 3 Installation of piezometer A on the floodplain transect.

A hole is hand augered to insert outer casing to a depth of 5 m (2m below water table).

Plate 4 Installation of tube B. Note the grey outer casing with retraction handle. The bailer is on the right. Piezometer A is covered with a coke can.

Plate 5 Slotted part (0.2 mm width) of 50 mm PVC casing is covered with double layer of pantihose (decitex 20) and taped to keep the material in place.

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20

28

31

33 34

37 46

49

50

53 55

56

57

58

63

3

3

7

7

8

Plate 6

Plate 7

Plate 8

Plate 9

Plate 10

Plate 11

Plate 12

Appendices

The slotted PVC casing is inserted into outer casing (piezometer B). Water is poured between the blue casing and the grey casing to facilitate lifting of the outer casing (while keeping the blue casing in place). The piezometer is cut to leave only a short length above ground. Note the grey outer casing to the right. No filter sand has been used. Levelling of the piezometer sites with the Wild electronic tachymeter (TC 500). Note the elephant in the background. First pumping test (site AB) on the main flood plain transect. In the background the rapidly incoming flood waters which took us by surprise. First pumping test (site AB). The hole is pumped at 24.8 m3/day (for 65 minutes). Development was not necessary. Pumping test site near the Okavango Research Centre Weir (site CDE). Two piezometers are being monitored. Pump rate 16 m3/day (for 5 hOurs).

A. Construction details of piezometer and weir

B. Survey data

C. Observations of surface and groundwater levels (Feb. 1997 - July 8, 1997)

D. Well test data

E. Particle size analysis

F. Porosity, bulk density and hydraulic conductivity

G. Hydrochemistry

H. Computational note on flow to a well in a water-table aquifer

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8

9

14

14

21

21

Abstract

In the framework of ongoing work in the Okavango Delta by the Okavango Research Centre (Maun) and groundwater investigations in the vicinity of Maun, research was carried out to study the relation between hydraulic conductivity and grain size distributions of unconfined aquifers.

The basic hydrogeological investigations involved installation of a piezometer network on Chiefs Island (ORC research site), analysis of both bulk (disturbed) and ring (undisturbed) soil samples, development of small scale well testing techniques and hydrochemical analysis of surface water and groundwater.

The outcome of this small co-operation project between GS (0. Obakeng) and UB (A. Gieske) included improvement of shallow piezometer installation techniques, a new relation between grain size distributions and hydraulic conductivities, while well tests in the unconfined aquifers were analyzed with the most modern techniques available. The ring test analysis not only produced values for the hydraulic conductivities of the fine to medium sands encountered, but also made it possible to derive values for porosity and bulk density.

The outcome of the project will be of great value for the ongoing multi disciplinary work in the ORC research site on Chiefs Island. It will also be used in the ongoing investigations of the Shashe Wellfield (Maun), which includes evaluation of the pilot artificial recharge tests.

Moreover, the study proved that the sinuous features, which are clearly visible on aerial photographs and satellite imagery, may be positively identified with former river beds: so-called palaeo-channels.

Finally hydrochemical analysis of both surface water and groundwater samples, indicate which hydrochemical changes are taking place when the seasonal flood waters infiltrate below the surface and recharge the groundwater of the upper unconfined aquifer.

(viii)

1 General Introduction

1.1 Objective of the study

Outflow from the Okavango Delta through the Jao/Boro River into the Boteti has been steadily declining over the past decade. The reasons for this decline are not well understood at present. Basically, the outflow depends on (a) rainfall in the area (b) inflow through the Okavango River and (c) the previous year's outflow (Dinc;er et al., 1987). Statistically, factor (c) implies that the annual outflow series exhibits autoregressive behaviour of a type well known in groundwater recharge modelling. Thus the hypothesis was put forward by Gieske (1997) that outflow from the Delta depends to a certain extent on interaction between surface water and groundwater. However, little is known about groundwater level fluctuations in the Delta or about the nature of the underlying aquifers.

It seems important therefore, to start basic hydrogeological investigations of some small catchments in the Delta. The present study, a small collaboration project between the University of Botswana, Okavango Research Centre and the Geological Survey Department, tried to address some simple, nevertheless fundamental, issues.

Specifically, the project objectives were:

Development of a simple manual technique to install shallow piezometers extending to a depth below the water table.

Install a network of piezometers to monitor shallow seasonal groundwater level fluctuations.

Survey the catchments to enable future modelling of groundwater flow.

Study of the relationship between grain size distributions and hydraulic conductivity of the shallow water-table aquifers.

Study of in situ porosities and bulk densities.

Develop a technique of small scale pumping tests to study aquifer specific yield and transmissivity values.

Contribute to the understanding of the hydrochemistry of both surface water and groundwater.

1.2 Study Areas

The study areas are located in the northwestern Botswana, on the flood plains of the Jao/Boro River in the Okavango Delta (see Fig. 1 and Plate 1). The Jao/Boro River is a complex system of meandering and anastomosing channels, perennial flood plains,

1

I: I

interlinked small oxbow type lakes and lagoons (locally known as Madiba) of varying sizes, which forms the central part of the Okavango Delta in northwestern Botswana. The Jao/Boro system receives only about a third of the total Okavango inflow (l1x109 m3/yr), but accounts for most of the outflow from the Delta into the Thamalakane and Boteti Rivers. The remaining two thirds of the inflow is transferred to the Thaoge and Khwai systems (Fig. 1). The average water depth is 1.5 -2.0 metres. However, in some Madiba and larger channels the average depth can attain 5-7 metres. Apart from the aquatic vegetation flanking the channels and forming the swamps there is an extensive submerged macrophyte vegetation in the Boro River. River and channel beds consist largely of sand while on riverine and island fringes calcic luvisols and arenosols occur.

The first catchment area which is called Beacon Island, was studied by Din<;er et al. (1976). This area, although perennially flooded in the 1970s, has not received any inflow over the past 6 years. A limited study has been ongoing during the past years with a view to study the receding groundwater levels in the area.

The study area (ORC site) which is most important for this project, lies on Chiefs Island, adjacent to the Boro River. The area forms part of a research site of the Okavango Research Centre (Ma un) and is regularly flooded, even during the prevailing low flow regime (see Fig. 2 and Plate 2).

o so km , , , ,

11' E

Kwando

Botet permanent swamp

J' I?I! seasonal swamp ~

-\? 13' E H' E

ORe site

Beacon Island site

Fig. 1 Map of the Okavango Delta showing Beacon Island and ORC site.

2

Plate 1 Boro River with Chiefs Island in the background.

Plate 2 Inlet channel from the Baro River into the floodplains (ORC weir site).

3

"'"

------,,' -,c,__ _ .. ~" ... ,,==, ,==.==,.=. ====

UTM grid (scale km) zone 34

medium to dense forest

7839 I h'~W 1 floodplaln/low bush/

7838

7837 727 728 729 730

grasses

D island interior/grasses

D flooded on July 5, 1997

~ direction of flooding

~ BoroRiver

main track

• piezometer

Fig. 2 Simplified location map of ORC site on Chief's Island, showing piezometer sites.

1.3 Previous Studies of the Delta's Hydrology and Water Chemistry

Detailed studies of the swamp's hydrology were made by SMEC (1987), Dinc;er et al. (1987), Scudder et al., (1993) and recently by Gieske (1997), while the results of the Witwatersrand University research group with regard to channel evolution and sedimentation processes may be found in many publications by McCarthy and co­workers, e.g McCarthyand Ellery (1994, 1995). Surface water chemistry has been studied by Hutchins et al. (1976), Sawula et al. (1992) and Cronberg et al. (1996). The water can be characterised as calcium-sodium bicarbonate, with moderate alkalinity to moderate to large amounts of silica. Important information with regard to aquifer structures in the southeastern marginal fringe of the Delta became recently available through the Maun Groundwater Development Project (MGWDP, 1997).

1.4 Field and laboratory activities

This report contains an account of field and laboratory methods which were employed to determine the hydraulic conductivity of the Okavango sequence sediments near the Boro river and the surrounding floodplains. It describes in detail the installation, surveying and testing of a shallow piezometer network. The report also covers the hydrochemistry of the groundwater and surface water of the area. The field work was done between April 1997 and July 1997 with the assistance of the Okavango Research Centre (University of Botswana (UB), followed by laboratory work at the Deparlment of Geological Survey (DOS) and the Departments of Geology, Environmental Science and Chemistry (UB).

The field activities involved

construction and installation of 17 piezometers (ORC site). collection of water samples for chemical analysis (ORC site). collection of auger samples and ring samples for grain size analysis and determination of hydraulic conductivity (both Beacon Island and ORC sites). small scale pumping tests, with a submersible electrical pump, normally used for hydrochemical sampling (Grundfos MP-I) (ORC site). daily recording of the impact of the seasonal floods on groundwater levels in the area. This included daily surface water level monitoring by means of weir and gauge (ORC site). surveying of the ORC site with an electronic tachymeter (Wild TC 500).

Laboratory work included setting up of permeameters to determine the hydraulic conductivity from ring samples collected during augering of piezometer holes. Other types of analysis such as sediments grainsize analysis were performed by the DGS­mineral dressing laboratory and UB laboratories (Geology, Chemistry and Environmental Science).

5

2 Field methods

2.1 Installation and construction of piezometers

The techniques of installing piezometers to almost any desirable depth by standard drilling methods is well developed. Many of these were installed in the Maun area recently during the Maun Groundwater Development Project (MGWDP, 1997) employing normal circulation mud drilling. Substantial capital investment is required to install these piezometers with the required heavy drilling equipment.

Recent hydrological research inside the Delta, however, has consisted of low budget, short term field activities (see for example: McCarthy and Ellery, 1994). Groundwater levels were measured by handaugering holes to the water table, leaving uncased holes behind which are prone to collapse. This made it often necessary to repeat the drilling at the monitoring time intervals. Moreover, the augering technique used does not allow penetration below the water table. Therefore there is a need to install low budget, but

more permanent holes, penetrating several metres below the water table to be able to monitor groundwater level fluctuations for a succession of seasons.

Techniques for achieving this are well known, but, surprisingly, have not been applied in the Delta area before. The following method, illustrated by plates 3 to 8, was tried and improved during three successive field trips to the ORC site (February, April and July, 1997):

1. Holes are handaugered to the water table using a riverside auger (diameter 11 cm), allowing an outer casing to be inserted (threaded pvc pipes, 1m length).

2. Sediments below the water table are removed from within the casing with a hand bailer, allowing the casing to sink below the water table.

3. PVC piezometer pipe (threaded 3m pipe, diameter 50 mm) is then inserted into the outer casing, after which the outer casing is pulled up while keeping the piezometer in place. The bottom end of the pipe is slotted (width 0.2 - 0.3 mm).

4. The hole is backfilIed, as much as possible with the same sediments, after which the pipe is cut about 10 cm above ground level. Coke cans tightened with a hose clamp, provided a convenient temporary cover.

It was found after the first trials that backfilling with coarse filter sand did not prevent fine silts and sands to enter through the slots (Fig. 3), thus leading to loss of effective piezometer length. Following a suggestion by Dr Beekman (UB), the slots were covered with pantihose (20 decitex) material (as an improvised geotextile) and taped in place (Plates 5 and 6). Fig. 4 shows a typical result obtained with this technique. Filter sand was not necessary and no further development was required. The holes could even be pumped easily after removing some fine pipe cuttings by manual bailing.

6

Plate 3

Plate 4

Installation of piezometer A on the floodplain transect. A hole is hand augered to insert outer casing to a depth of 5 m (2m below water table).

Installation of tube B. Note the grey outer casing with retraction handle. The bailer is on the right. Piezometer A is covered with a coke can,

7

Plate 5 Slotted part (0.2 mm width) of 50 mm PVC casing is covered with douhle layer of pantihose 20) and to keep the material in

Plate 6 The slotted PVC casing is inserted into outer casing (piezometer B).

8

Plate 7

Plate 8

Water is poured between the blue casing and the grey casing to facilitate lifting of the outer casi keeping the blue casing in place).

The piezometer is cut to leave only a short length above ground. Note the grey outer casing to the right. No filter sand has been used.

9

The difficult part of the exercise was found to be the pulling up of the. outer casing, while keeping the piezometer in place. Sand enters the annular space between the outer casing and the piezometer pipe, which tends to stick the casing and pipe together. It is advisable to maintain overpressure by pouring some water (Plate 7) in the annular space. Depending on the type of water level measuring equipment available, it may also be

advisable in future to try piezometer pipe with smaller diameters (1 to 2.5 cm).

Construction and installation details of all piezometers can be found in Appendix A.

1

piezo 2 (on transect 1 flood plain)

0 surface

~

E - 1 ~

~ -2 .g solid casing

:J '" 3 -3 slotted " ..- bottom hole Q ID

casing sediment .0 -4-

~ -- 5 ID

lJ

-6

-7

Fig. 3 Construction of piezometer 2. Silts and fine sand have entered through the slots, thus reducing the effective piezometer length.

1

0

E -1 ~

~ -2 .g iil 3 -3 Q ID .0 -4-

~ Q. ID -5 lJ

-·6

-7

piezo A (on transect 1 flood plain)

sOlidI casing

slotted casing

- surface

WL June 28, 1997

Fig. 4 Construction of piezometer A. Pantihose (20 decitex) works as an effective geotextile.

10

2.2 Survey of the ORe site and piezometers

Part of the catchment and some of the installed piezometers were surveyed with a Wild electronic tachymeter (Te 500): a "total station". The survey data are contained in Appendix B. Figs 5, 6 and 7 show the position of the benchmark on the weir (see also Plate 2 and Fig. 2).

The piezometers 1, 2, 3, 4, A and B (Fig. 2, Plates 3-10) on the flood plain transect were all tied in to the weir benchmark. Fig. 8 shows the groundwater levels on this transect together with the piezometers for two different dates (April 27 and July 8, 1997). The

. transition from low to high groundwater levels took place within a couple of days in the beginning of July, as will be discussed further in the next section.

The positions and elevations of piezometers e, D, E, F, G, J, K (Fig. 2) were also determined. Not yet surveyed are piezometers Camp, Obs Island, H (dry clay) and I.

It was decided to survey also a transect from the Pan (Fig. 2) to the weir. From the weir the flood waters flow North first. When this Northern part of the catchment is almost filled, water starts flowing East into the Pan Catchment from the branch off point 100 m North of the weir. Fig. 9 illustrates the situation. Only when the Northern channel reaches the level of the bank, water starts flowing over the surface into the deeper Pan Catchment. Simultaneously, ground water levels will rise to the surface. This will be discussed further in the next section.

legend

• pools

m flooded channel

trees

Fig. 5 Map showing ORC weir site and benchmar,k position. /

11

0.15 south

r-

E 0

'--' '" 0

c 0

:;::: 0.0 0 > (I) (I)

-0.6 o .20

o o

40

north

y = - 0.002278 x + 0.233771

o o o o

o

weir

60 80 100 1.20

distance along thalweg Cm)

Fig. 6 Gradient of main inlet channel around the weir site.

2 ~

o 20 40

distance Cm)

60

Fig. 7 Cross-section of the inlet channel at the weir site showing construction of the weir.

12

1.0

0.0

plez.1

forest plez2

AB

~

E -1.0 ~

C 0

+= 0 > (!) (!)

-2.0

July 8. 1997

-3.0 April 27. 1997

-4.0

-5.0 -100 o 100 200 300

distance along flood plain transect 1 Cm)

Fig. 8 Transect on the main flood plain (see Fig. 2), showing location of piezometers. Note the ridge between channel and floodplain. Flooding occurs when the level in the channel rises above the bank at a spot where the bank level is lowest.

2

"" E ~

"" 0 0 E .r: 0 c -1 <D

.D

.2 -2 "2 0 Ol <D -3 ~

.r: "= 3:

Q) > ~

o

ridge with riparian forest

piezometer G

Piezome~lt~e~r ~F __ ~~~::---':'::W::"""""'''''::''l -- surface

main pan

500 1000

distance along transect Cm)

main channel

1500

Fig. 9 Transect along the main eastern branch through the pan to the forested ridge. Flooding of this eastern branch starts only when the water level in the northern channel with associated flood plains has reached a threshold level.

13

Plate ~O

L,evelling of the piezometer sites with the Wild electronic tachymeter (TC 500). Note the in the background.

First pumping test (site AB) on the main flood plain transect. In the background the rapidly incoming flood waters which took us by surprise.

14

2.3 Water level observations

2.3.1 Surface water levels

During the fieldwork (28 June - 8 July) flood waters were entering the catchment and surface water and groundwater levels were steadily rising. Groundwater and surface water levels were recorded once a day. All measurements and hydrographs can be found in Appendix C. Fig. 2 shows the extent of the flooding on July 5, 1997. Fig. 10 shows the rise of the Boro River water level near the Camp Site on Half Moon Island since June 13. High levels were reached on June 30, after which the level remained approximately constant. This hydrograph should be compared with Fig. 11 and 12, showing respectively the rise in level at the weir site and the rise in the main Northern Channel near the transect. At both points the water was still riSing in the first week of July, indicating that the catchment was slowly filling up. During the first week of July, water started also overtopping the threshold leading to the pan in the eastern part of the catchment, i.e. towards piezometers G and F. Surface water had arrived near piezometer G on the 8th of July. Surface water was also flowing into the floodplain near piezometer H. In the northern part water was flowing steadily further north in the channel. The pattern of flooding is complex. Even in this small catchment a number of sub-compartments can be distinguished, which only start filling when thresholds in adjacent compartments have been reached.

0.40 ,--------------------,

~ 0.30

~O

E E ~.c:

c: u 0.20 o c +=0) ~.Q (j) 0 <1>.5 0,10

Boro River level near Camp Site

o ,00 +----:-c:-~__:c:_-__:c:_-_::>::__-::y::_-__,:--_f. 5 10 15 20 25 30 5 10

Fig. 10

June 1997 July 1997

Rise in Boro River water levels near the Camp Site on Half Moon Island (period June 13 - July 8, 1997).

15

. -0.16

-0.18

C -0.20 o :;::

~ -0.22

(j)

-0.24

weir level relative to benchmark

-0.26 4------r-----::r:-----~-----!,0 20 25 30 5

June 1997 July 1997

Fig. 11 Rising water level at the weir, relative to benchmark.

-0.16

-0.17 Floodplain main channel staff gauge on transect 1

~

E -0.18 ~

c: 0 -0.19 :;:: 0 > -0.20 (j) (j)

-0.21

-0.22

-0.23 85 90 95 100

24-JUN-97 09-JUL-97

Fig. 12 Rising water level in main northern channel (see Figs. 2 and 8).

16

2.3.2 Groundwater levels

Ground water levels generally showed a rapid increase after flooding. Fig. 13 shows the hydrograph of piezometer 2 on the floodplain transect as an example. All other hydro graphs can be found in Appendix C. Flow through the weir is being monitored by ORC staff. No data are available yet.

In the absence of surface inflow groundwater levels are receding at a rate of 1.5 to 2 m per year (at a depth of 3 m below the surface). Close to the surface, immediately after flooding the recession rate is probably higher, because of the evapotranspiration of grasses. This explains the surprising fact that groundwater levels are 3 m below the surface of a flood plain that is annually flooded. The recession is due to (a) evapotranspiration and (b) lateral outflow towards the riparian forest, where groundwater levels are kept low due to the large tree evapotranspiration. It is also clear from Fig. 13 and all other hydrographs of this transect that infiltration rates are high once the flood arrives (",1.5 m/day).

The hydrographs of piezometers C, D and E close to the main inlet channel near the weir show a more gradual increase (Fig. 14) as a result of the steadily rising levels in the main channel.

Piezometer F, at that time far away from the advancing floods, still shows a recession at a rate of about 1.4 m/yr.

The rapid changes of the groundwater levels due to the advancing floodS, illustrates the highly dynamic nature of the catchment water balance. The hydrographs also show that understanding of surface water-groundwater interactions is crucial to the modelling of surface water outflow through the Jao/Boro River system. The groundwater storage and outflow component in the overall catchment water balance seems to play a larger role than assumed thus far.

The flooding of the 1997 season seems minor compared to other years. Fig. 16 shows the extent of the flooding in August 1991. The main pan in the eastern part of the catchment is completely filled and even spills over to flood plains further east. Half Moon Island has become surrounded by water completely. Under these circumstances it does not seem unlikely that surface water flow may reverse direction once the Boro River levels start dropping. Southward flow through the main channel back into the Boro cannot be ruled out. This mechanism would 'add further complications to surface outflow modelling.

In view of the high infiltration rates, recharge by rain seems important during good rainy seasons. This would lead to rapid rises of the groundwater table, thus decreasing storage space for subsequent flooding events. It is important to continue monitoring to be able to quantify the effect of rain recharge events on flood water balance components.

17

i Ii \: i

H q : , i

I: 11

li

l l

Fig. 13

~-<!: EO ~E -.c <Du ~~ ~.D

~o O+-3u U<D cu :>:> QU Cl!!!

Fig. 14

0.00 -r------------------_, piezometer 2 flood plain on transect 1 surface level

-1.00 -:

-2.00

-3.00

bottom piezometer -4.00 ;

-5.00~----~---~~---~~---~ 20 40 60 80 ,00

20-APR-97 09-JUL-97

Hydrograph of piezometer 2 (installed in April 1997). Water level receded below the sediment collected in the pipe, probably not far. Recession rate can only be estimated ('" 2 m/yr). The infiltration rate (rise of the water table) was in the order of 1.5 m/day.

-0.35 g--------------------~

-0040

-0.45

-0.50

-0.55

-0,60

-0.65

-0.70

piezometers C.D and E near the weir

• C o Dand E

-0.754--,--_-.--_-__ --.--_-_-~ 90 91 92 93 94 95 96 97 98 99 ,00

29-JUN-97 09-JUL-97

Rise of groundwater levels in piezometers C, D and E (close to the weir site) during the fieldwork period is caused by the gradual rise of surface water in the inlet channel (see Fig. 11).

18

Fig. 16

Fig. 15

-4.58 ~--------------__________________ --.

-4.59

-4.61

piezometer F near the road on pan inlet channel

- 4. 62 '±---::r---=,=--~:---=--::-r:---:"'----'=-~---=---.j 90 91 92 93 94 95 96 97 98 99 100

29-JUN-97 09-JUL-97

Hydrograph of piezometer F on the inlet point of the large pan in the eastern catchment (Fig. 2). This hydrograph is still far from the advancing floods on July 8, 1997, and therefore shows natural recession (:::<1.4 m/yr) because of evapotranspiration (see also Fig. 9 which shows the position of F on the transeCt through the pan).

scale 1 : 50 000

Aerial photograph of the catchment (28 August, 1991), 91/1, Okavango Run 21, 255. Compare the extent of the flooding with Fig. 2. The pan is overflowing to the right. Half Moon Island is completely surrounded by water. The Boro River is clearly visible in the bottom left corner.

19

2.4 Well test Analysis

2.4.1 Introduction

The 50 mm inside diameter of the piezometer pipes was just large enough to allow installation of a small submersible electrical pump (Grundfos MP-I) and small scale experimental pumping tests could therefore be conducted. At a few locations additional observation holes were installed at short distances from the pumped holes (see Table 1). All test data can be found in Appendix D. The shallow piezometer holes only partially penetrate the upper unconfined aquifer (Plates 10, 11, 12 and Fig. 17).

Table 1 Summary of the experimental small scale pumping tests

site pumped observation constant rate recovery remarks hole holes CRT

time (min) time (min)

AB A B 65 90 flooding problems CDE(I) C D,E 90 75 CDE(2) C D,E 300 90 best test F F 120 Zangar method G G 180 90 JK J K 135 90

The general solution to this problem was first presented by Neuman (1974) while improved solutions were recently published by Moench (1996, 1997). Moench's (1996) solution is implemented by the Aquifer Test Package (1997) of Waterloo Hydrologic Software. This method assumes that the pumped well is a line source and wellbore storage effects are therefore neglected. The further improved solution, including wellbore storage and skin, is discussed by Moench (1997).

The analysis presented here is based on:

(a) The Standard Jacob analysis for Constant Rate (CRT) and Recovery tests (Kruseman and De Ridder, 1991)

(b) The Zangar method to determine hydraulic conductivity, as described by ILRI (1974)

(c) The Moench (1996) method

Additional complications arose from the fact that most groundwater levels were rising as a result of the advancing floods. Well test AB even had to be abandoned after an initial trial, because the advancing floods reached the test site! (Plate 10, page 14). In most cases drawdowns were corrected for the rising groundwater level. Finally, because the pumping tests were of short duration (Table 1), late time increase of drawdown was not observed, and the analysis is restricted to early and middle times.

20

Plate 11

Plate 12

First pumping test (site AB). The hole is pumped at 24.S m3/day (for 65 minutes). Development was not necessary.

Pumping test site near the Okavango Research Centre Weir (site CDE). Two piezometers are being monitored. Pump rate 16 m3/day (for 5 hours).

21

(1:'. I, it

ih d: !i

11

11

I

1

r-.

E "--'

<l> ()

.E ~

:::l en

~ <l> .0 .s::. -t-Q. <l> <J

Fig. 17

1 -= ~ D C E

surface ---~ solid ~ - ~ ~ water table '" _.-

0

1 ~ ~ , screen .~ ~

- 1

j i

-= I i ~ 2 -

1 ~ pump - :3

~ I:. ,

- 4 --= 0.47m 0.225 m

~ fine sand ~ aquifer ~ ~

1 ~

- 5

- 6

~7

Pumping test site CDE near the weir, showing pumped hole C and the two observation holes D and E. Two tests were conducted at this site (see Plate 12).

50mm

54mm

slot width 0.3 mm

Fig. 18 Construction of the slotted pipes, showing distribution and size of slots.

22

2.4.2 Methods

In unconfined aquifers, time-drawdown curves on a double logarithmic paper are usually S-shaped, consisting of a steep early time segment, a flat intermediate time segment and a relatively steep late time segment (see Fig. 19). The feature has been attributed to delayed water table response. The theoretical approach by Neuman (1972) is stilI widely accepted as the best solution, although the recent series of publications by Moench (1993, 1994, 1995, 1996 and 1997) indicates that the theory and practice of pumping tests in water-table aquifers is stilI progressing. A number of approximate methods can also be applied, which are briefly described below (A, B and C). The Moench (1996) method is briefly described under (D).

10'

earlyffme Thais Type A

r= 0.4 mlddleffme

10" ' l/u

lateffme Thais Type S

10' 103

Fig. 19 Type curves for well testing in water-table aquifers (Neuman, 1972).

A. Jacob approximation

On semi-logarithmic graph paper the early and late time segment should plot as parallel straight lines if the Theis and Jacob assumptions are met (Kruseman and De Ridder, 1991).

The Jacob solution is an approximation to the Theis equation, for which the drawdown (s) in an observation borehole close to a pumping well is given by:

where

$= 2.3Qlog (2.25Tt) 41tT 10 Sr2

r is the radius of the piezometer Q is the pumprate t is the time T aquifer transmissivity S aquifer storativity

23

( 1)

The Jacob solution assumes the following the aquifer is confined and has an apparent infinite extent the aquifer is homogeneous, isotropic, of uniform thickness over the area influenced by pumping the piezometric surface was horizontal prior to pumping the well is pumped at a constant rate the well is fully penetrating, thus receives water from the entire saturated thickness of the aquifer water removed from storage is discharged instantaneously with a decline in the head. the well diameter is small so that well storage is negligible the values of the well function u are small (u<O.Ol)

Although the aquifer is assumed to be of uniform thickness, this condition is not met if the drawdown is larger compared with the aquifer's original thickness. A correction to the drawdown may be made to approximate unconfined conditions according to the following relation:

(2 )

where scor is the corrected drawdown, s the measured drawdown, and D is the original saturated' aquifer thickness.

Despite the obvious difficulties in applying the Jacob-Theis method in the present situation, Equation 1 has been used in the analysis of CRT data, by making a plot of s against t on a semi logarithmic paper. The graphs of CRT tests are contained in App. D.

B. Recovery Tests

When pumping ceases, the well and the aquifer rise to their original static water levels. The recovery data provides a way of calculating the transmissivity (T) in the absence of an observation borehole according to:

T=2.3 Q 41tLls'

(3)

Lls' is obtained from the residual drawdown( s') against tit' (total time since pumping began divided by the time since the pumping ceased) plotted on a semi logarithmic paper. The transmissivity is then determined according to equation 3. Graphs of recovery data obtained from the field are contained in appendix D.

C. Zangar method

The principle of the method is illustrated in Fig. 20. The Zangar solution (ILRI, 1974) assumes a partially penetrating pumping hole in which water is discharged at a constant rate (Q). When the water level in the pumping hole has reached equilibrium, the hydraulic conductivity (K) is calculated according to:

24

where K Q r L H h

c

K~~ CLr

hydraulic conductivity (m/dar) constant rate of pumping (m /day) radius of the borehole (m) (H2-h2)/2H

(4)

depth of the borehole below the initial groundwater table (m) stabilised height of the water level above the bottom of the hole at equilibrium (m) function of hand r referred to as the geometric factor (see Fig. 21)

initial ________________________ Qlil ____ ~g~rO-U-n-dw-a-t-er-t-ab-le--------

aquifer

Fig. 20

H

If --y- 2r

s

stabilized groundwater table

Parameter definitions in the Zangar method (see Eqn 4).

l03~----------------------------------------------,

10'

c

10'

10° 10' 10' 10' h/r

Fig. 21 Geometric factor C as a function of h/r (Eqn. 4).

25

D. The method for partially penetrating boreholes by Moench (1996).

The Moench solution (Moench, 1996) is an improvement of the Neuman solution (Neuman, 1972) for drawdown in a homogeneous, anisotropic, confined or unconfined aquifer, with either a fully or partially penetrating pumping borehole and multiple observation wells. The Moench solution alsG allows water in the overlying unsaturated zone to be released in a response to a declining water table either instantaneously (Neuman) or gradually (Boulton) through change in parameter y. The delayed yield is approximated by Boulton's convolution integral (Nwankwor et aI., 1992, Boulton, 1954, 1963). Fig. 22 illustrates the parameters for an unconfined aquifer in which D is the thickness of the saturated zone.

The general equation developed by Moench for dimensionless drawdown hD in an unconfined aquifer is

where

y is a dimensionless fitting parameter that incorporates the effects of delayed drawdown, and a is an empirical constant, ZD is the dimensionless depth of the piezometer, tD is the dimensionless time, hDT is the dimension less drawdown for a well in a confined aquifer, ahDH is the deviation from the Theis solution due to effects of partial penetration in a confined aquifer (Hantush component), AhDN is the deviation from the Theis solution due to effects of the free surface (Neuman component).

Piezometric surface before start of pumping

Observation

""" ---------------------------- ",'f . ,," ,,',,',"--""

Fig. 22

's, ~ Piezometric surface t bt after start of pumping

b b, 1 1 L.' H ~:1

-R

o

1 aquifer

Parameters for the pumped well and the observation holes in the Moench (1996) method.

26

For unconfined aquifers, in which both the pumping well and the observation well are fully penetrating, the solution is the same as the Neuman solution. The Moench solution uses dimension less parameters for the type curves with log(tdy) plotted on the x-axis and log(hd) plotted on the y-axis. The data scales are 10g(tjrZ) on the x-axis and log(s) on the y-axis.

The Moench solution assumes that: the aquifer has an apparent infinite extent the aquifer is homogeneous and isotropic drawdown is small compared to saturated thic!mess the piezometric surface was horizontal prior to pumping the well is pumped at an average rate the well diameter is small so that well storage is negligible

Most of these assumptions seem to be met in the present situation. Moench (1994) further pointed out that reliable values of Sy can be obtained through simultaneous fitting of drawdowns obtained from multiple observation wells.

Some suggestions for improved implementation of the Moench (1996) method were made by Gieske (1998) (see Appendix H).

2.4.3 Results and Discussions

A. Jacob Analysis

The results of the straightforward Jacob analysis of the CRT and recovery tests are presented in Table 2 below. Figs. 23 and 24 illustrate the analysis with CRT and recovery tests for piezometer D (site CDE, 2nd test, duration 5 hours, recovery 90 minutes). In drawing a straight line for the CRT test the early points have been ignored (probably wellbore storage effects) as well as the last points where the curve flattens (water table decline according to Neuman, delayed yield according to Boulton). In the recovery plot all points can be used for the fit. All other test plots can be found in Appendix D.

Transmissivity values for the CRT tests range from 22 to 70 m2 / day while those for the

recovery tests are slightly higher from 29 to 104 m2/day. Site AB has the highest transmissivity, site CDE the lowest. Storativity values rang from 0.5 to 4 %. It should be noted that lower S values are usually found in the early time domain. The reason for these high S values is probably that the tests were conducted very close to the groundwater table, where pressure effects are bound to be small. Estimates for the specific yield Sy cannot be obtained through the Jacob analysis as applied here in the early time domain. However, composite plots using the Moench method will produce Sy estimates, as is discussed below.

27

Table 2 Results Jacob/Theis manual analysis (drawdown plots, App. D, pp 10-16).

A. constant Rate tests

hole Q As T r to S (m3 Id) (m) (m2/d) (m) (min)

B1 24.75 0.0650 69.69 0.380 0.007 0.0053 D1 16.14 0.1075 27.48 0.470 0.160 0.0311 D2 16.07 0.0960 30.64 0.470 0.080 0.0173 El 16.14 0.1235 23.92 0.225 0.100 0.0738 E2 16.07 0.1040 28.28 0.225 0.030 0.0262 K1 19.00 0.1550 22.44 0.570 0.120 0.0129

B. Recovery tests

hole Q As T !l (m3 Id) (m) (m2 Id) , , I'

24.75 iI B1 0.0435 104.14

11' D1 16.14 0.0790 37.39

III D2 16.07 0.0950 30.96

II El 16.14 0.0950 31.10 "I E2 16.07 0.1025 28.70 avg (D1,D2,E1,E2)

1I 32.04 ± 3.24

, i G1 8.67 0.0390 40.69 !i K1 19.00 0.0680 51.14 ii

C. Results of CRT and recovery combined and averaged T (m2 Id) S

CRT REC

AB 69.69 104.14 0.0053

CDE 27.48 37.39 0.0311 30.64 30.96 0.0173 32.92 31.10 0.0738 28.28 28.70 0.0262

JK 22.44 51.14 0.0129

D. Overall averages T S

(m2/d) AB 86.915 0.0053 CDE 30.934 0.0371 G 40.690 JK 36.790 0.0129

28

0,4

0,3 ~

E ~

c 3 0 0,2 "0 3 0 U

0,1

Fig. 23

0,4

~ 0,3 E ~

c 3 0 "0 3 0,2 !2 "0 0 ::J "0 'u; 0,1 ~

Fig. 24

constant rate test 02 02-JUL- 1997

I--

I--

/

11 11111 11

draw down per log cycle t;. s = 0,096 m

to= 0,08 min

V

/00 0

V

101

time (min)

/ /0 0

v

Drawdown plot of constant rate test at site CDE. C is the pumped hole. D and E are observation wells (see Plate 12 and Fig. 17). The observations at early times are probably influenced by wellbore storage, while the flattening above 100 min is caused by the phreatic nature of the aquifer.

recovery test 02 02-JUL- 1997

dr awdown per log cycle /). s = 0,095 m

tit'

/' .~

,Y v

Residual drawdown plot of recovery test at site CDE. Piezometer D, second test.

29

B. Results obtained with the Zangar method

The Zangar method (Zangar, 1953, ILRI, 1974) is interesting, because it allows determination of hydraulic conductivity (k), as opposed to the other well test methods which determine transmissivity (T) values. Since the thickness D of the unconfined aquifer is unknown, the T values cannot reliably be converted into k values (T=kD).

It was not possible to verify the assumptions underlying the Zangar method because . the original Zangar (1953) paper was not available and the description by

ILRI (1974) is too superficial. The method, as applied here, is based on Eqn 4, page 25.

Furthermore, it proved impossible to determine the water level in the pumped hole during the tests. The diameter of the connectors on thepVCrising main seglt,ments was too large to allow access to the dipper. Therefore the steady state water levels were estimated as illustrated in Fig. 25. hIo is the distance from the bottom of the hole to the pump intake, which is the smallest possible h. It was further assumed that the maximum possible h, hhi' was halfway between the pump intake and the original water level. Two k values can thus be found: khi for hhi and kIo for hIo' As is shown in Table 3, the results for these different h values are not really far apart. In comparison to the other test results, however, the k values seem too high. This will be discussed further in the section on the results of the permeameter tests (section 3.3). Meanwhile, it should be noted that application of the Zangar method is promising, but needs further theoretical analysis with regard to underlying assumptions and field practice, with the view to improve water level measurements in a single pumped small diameter well.

Fig. 25

- surface

3 "0 Q) 0. E :J initial groundwater table 0.

• • ,

i~~;oo , :a , , , -----1----, , & ' ,

: : a H , , , , , , : ---,,---- • - - - - -:6.- - - - - - pump intake , , , , , ,

: hhi , , ,

hlo , , , , , , ____ t __ t ________ ,

v bottom hole .------------

Definition of parameters for the Zangar method as applied in this report (see also Fig. 20).

30

Table 3 Zangar method input data and results (Zangar, 1953, ILRI, 1974).

input data " Toe screen TOe Toe Toe bottom depth length top of water pump H h10 hhi

screen level intake

(m) (m) (m) (m) (m) (m) (m) (m)

A 4.73 2.94 1. 79 2.84 4.00 1.89 0.73 1.31 e1 3.38 1.48 1.90 1.07 2.10 2.31 1.28 1.80 C2 3.38 1.48 1.90 1.03 2.85 2.35 0.53 1.44 F 5.18 1.02 4.16 4.07 4.95 1.11 0.23 0.67 G 4.75 1.91 2.84 3.53 4.53 1.22 0.22 0.72 J 3.28 1.85 1.43 1. 25 3.03 2.03 0.25 1.14

results Q H h 10 hhi k10 khi kav9 diff

(m3/d) (m) (m) (m) (m/d) (m/d) (m/d) (m/d)

A 24.75 1.89 0.73 1.31 25.92 28.21 27.07 1.14 Cl 16.14 2.31 1.28 1.80 11.48 15.81 13.65 2.16 C2 16.07 2.35 0.53 1.44 15.04 11.45 13.24 1. 79 F 5.00 1.11 0.23 0.67 16.67 12.65 14.66 2.01 G 8.67 1.22 0.22 0.72 26.72 18.54 22.63 4.09 J 19.00 2.03 0.25 1.14 31.99 16.90 24.45 7.55

C. Results obtained with the Moench method.

The Moench method is best suited for the present situation because:

a. partial penetration and screen length can be taken into account

b. it combines the approaches byNeuman and Boulton

c. it allows simultaneous fitting of drawdowns in several observation holes into so-called composite fits

It should be noted that the screens should be below the water-table at all times, because the method assumes constant screen length. This was not the case in the field tests described here (see for example Fig. 17, page 22). Future fieldwork should try to improve the piezometer installation in this respect. However, numerical testing indicated that the error is not large.

Fig. 26 shows a typical analysis for a pumped well site, using a single observation hole. The partial penetration results in a type curve which is different from the curves obtained for full penetration (see Fig. 19, page 23).

No storativity S or specific yield Sy can be obtained in this case, because p,!mp time (5 hr) was not long enough to obtain late time increase in drawdown. All test plots obtained

31

Fig. 26

Fig. 27

Th is early JIl}~(S 1------j-- _._-1-------c=~ ~-

tyPf[~~ --- - - ----well -- _ --- -/-

t--v -+---- '-- -71'-. LI __ L ___ TheiSI pte tim (Sy)

---- I--------

1/ t,· +--- .. -- it. i .- .----- ---.---- -----.------

I ... , '" ""

Illustration of a type curve for an observation hole, partially penetrating an unconfined aquifer. The dashe curves show the Theis curves for early (S) and late times (Sy). The plotted points are those for CRT D2 with y=3 and T=32.1 m2/day.

Illustration of the effect of changes in y on the transmlSslVlty values. See well tests (9,10), (12,13) and (15,16) in Table 4.

32

Table 4 Results of well test interpretation with the Moench method for unconfined aquifers with partiaLLy penetrating boreholes

nL.looer file site date Q T 0 S/Sy Kv/Kh Sy Kh Kv garrrna cooments conments .hyt (m3/d) (m2/d) (m)

1 B1CRT AB 29·JUN-97 24.75 49.4 10 0.010 0.1 4.94 0.494 1.0E+09 constant rate 2 B1REC AB 29-JUN-97 24.75 74.6 10 7.46 recovery 3 B1RECX AB 29-JUN-97 24.75 92.4 10 9.24 recovery no of points reduced

4 D1CRT CDE1 01-JUl-97 16.14 25.6 5 0.001 0.1 5.12 0.512 1.0E+09 constant rate 5 D1REC CDE1 01-JUl-97 16.14 33.6 5 6.72 recovery 6 E1CRT CDE1 01-JUl·97 16.14 18.1 5 0.001 0.1 3.62 0.362 1.0E+09 constant rate 7 E1REC CDE1 01-JUL-97 16.14 28.7 5 5.74 recovery 8 DE1CRT COE1 01-JUL-97 16.14 20.3 5 0.500 0.5 0.20 4.07 2.030 1.0E+09 composite fit

9 D2CRT CDE2 D2-JUl-97 16.07 22.7 5 0.001 0.1 4.54 0.454 1.0E+09 constant rate 10 D2G1CRT CDE2 02-JUl-97 16.07 32.1 5 0.001 0.1 6.42 0.642 3 constant rate gamma changed to 3 11 D2REC CDE2 02-JUL-97 16.07 30.7 5 6.14 recovery 12 E2CRT CDE2 02-JUl-97 16.07 14.3 5 0.001 0.1 2.86 0.286 1.0E+09 constant rate 13 E2G1CRT COE2 02-JUl-97 16.07 22.7 5 0.001 0.1 4.54 0.454 3 constant rate 14 E2REC CDE2 02-JUL·97 16.07 26.6 5 5.33 recovery 15 ED2CRT CDE2 02-JUl-97 16.07 18.0 5 0.001 0.1 44.50 3.61 0.361 1.0E+09 composite fit shows bad S/SY! ! ! 16 E02G1CRT CDE2 02-JUl-97 16.07 25.5 5 0.230 0.5 0.28 5.10 2.550 3 composite fit b,l(E) adapted

W 17 G1REC G 04-JUL-97 8.67 38.6 5 7.72 recovery W

18 K1CRT JK Q7-JUL-97 19.00 47.8 5 0.001 0.1 9_56 0.956 1.0E+09 constant rate 19 K1REC JK 07-JUl-97 19.00 47.2 5 9.45 recovery

Note 1. In test 16 the parameters band L (piezometer E) have been changed to resp. 1.10 and 1.00 m to improve fit. 2. All other b and l data can be found in App. D', pages 17, 24, 36, 53 and 56.

with the Moench method have been taken up in Appendix D (Aquifer Test, 1997). Table 4 shows the results of all CRT and recovery tests. The transmissivity values obtained are very similar to those obtained by the TJ:leis/Jacob method (Table2). Again site AB has the highest transmissivity values and site CDE the lowest.

The effect of varying y leads to systematic changes in the transmissivity values (Fig. 27). High y values (y= Ix 109

) lead to solutions identical to the Neuman model results, whereas low values (y=3) produce results by the Boulton approach of delayed yield from the unsaturated zone. Fig. 27 shows that for cases (9,10), (12,13) and (15,16) of Table 4 and a change from y= 1xl 09 to y= 3, an increase in transmissivity of 8 m2

/ d is found. The highest values seem the most appropriate here. Therefore, the transmissivity values obtained with the Neuman method may be underestimated.

Composite fits improve the modelling as is illustrated in Figs 28 and 29, and also allow determination of S, Sy> the vertical and horizontal conductivities (l<", kh) and a rough estimate of aquifer thickness D. Fig. 29 was produced with the method described in Appendix H.

The Moench (1996, 1997) methods seem to be the appropriate well testing tool for future work in the upper unconfined aquifers of the Okavango Delta.

2.4.4 Comparison of results

Table 5 summarizes the results of the well testing described in the previous sections. Transmissivity values obtained with the Theis/Jacob method correlate well with those by the Moench method. Simultaneous fitting of drawdowns in several observation holes has the added advantage of being able to determine values for S, Sy> k,., kh and D.

Comparison of the k values, obtained by the Zangar method, with the T values seems to imply aquifer thicknesses from 2 to 3 m. However, from the composite fit of site CDE an estimate of 5 m was obtained. Hence the Zangar method may overestimate conductivity values and further work is required on this method.

Table 5

AB CDE G F JK

Comparison of well testing results

Theis/Jacob T(m2/day) S

86.9 30.9 40.7

36.8

0.0053 0.0371

0.0129

Zangar k (m/day)

27.1 13.4 22.6 14.7 24.5

34

Moench T S/Sy Sy kjkh D(m)

72.1 24.5 0.37 0.27 0.5 5 38.6

47.5

data used for pumping test analysis piezometers C, D and E TEST (2) 2/7/97

D E 0,007 m C 0,019 m ....... " ........... """'f'"

0,19m surface

1,03 m

y " 'V

<4'" ....................... ~ .............. ~

0,47 m 0,225 m

pump intake 2,85 mTOC

Not e:

zero level

startCRT 10,17 hrs 2/7/97

rest water level 1,03 m below TOC C

piezometer C b =2,35 m L = 1,48 m piezometer D b = 1.33 m L = 1.33 m piezometer E b = 1,00 m L = 1,00 m

b 1, Water levels of piezometers D and E have been corrected by resp,

-0,007 m and -0,019 m to reduce them to the same level as TOC C (see Appendix A and B)

L

2, A level correction of 2,49 x 10-5 m/min has been applied to compensate for rising water level (see Appendix C),

Fig,28

10 1

hD

10°

Fig. 29

Illustration of piezometer and well screen data required by Aquifer Test (1997).

results

T 25,6 m 2 /d

0 S 0,06

Sy 0,32 well E

0 • Kr 5,12 mid

Kz 2,56 mid

y 3

10° tD

102 104

Composite plot of drawdowns in piezometers D and E (site CDE, test 2, see Fig. 17, page 22, and Fig. 28 above).

35

3. Laboratory methods

3.1 Introduction

In general Particle Size Analysis aims at obtaining grain size distributions of soil samples from 2000 !ill1 (very coarse sand) to below 2 !ill1 (fine clay minerals). For sands with low silt and clay content (i.e. below 50 !ill1) the analysis is simple. After oven-drying the samples are shaken in a stack of sieves and the fractions in each sieve weighed directly. With substantial amounts of clay, however, the laboratory analysis becomes considerably more difficult. It is necessary to separate the clay fraction from the sand fraction first, which requires a combination of chemical dispersion agents and mechanical action, such as vigorous shaking or ultrasonic vibration. Clay and sand fractions are then analyzed separately, using sieving for the coarser particles and settling rates in fluids for the fine sizes. For fine clay particles specific surface areas may be studied by various methods to determine particle sizes.

Thus particle size analysis for clayey soils may be worthless unless the soil is fully dispersed, and shortcuts that omit some of the dispersion procedures can only be taken with caution (Marshal! and Holmes, 1988).

The Okavango Delta sedimentary environment obviously contains a wide range of soils, from pure sands to heavy clays. The MGWDP (1997) has shown that aquifers in the distal end of the Delta consist of multilayered sequences of clays and sands to depths over 100 m.

In this project the hydraulic conductivity of fine to coarse sands is studied. Therefore dry sieving was considered appropriate to determine grain size distributions. However, unavoidably a' number of more clayey soils was also encountered,

Two sampling methods were used: (a) bulk samples were obtained with a riverside auger (b) undisturbed ring samples were taken with hydraulic equipment. Samples obtained by method (a) could only be used to determine grain size distributions, whereas those obtained by method (b) were used to determine grain size distributions, bulk densities, porosities and hydraulic conductivities (with a permeameter), Method (b) therefore allows us to determine a relation between grain size distribution and hydraulic conductivity. All methods are briefly described in the following sections.

3.2 Estimating hydraulic conductivity from grain size distributions

Grain size distribution may be expressed by a single parameter, the specific surface U of the sand fraction. This parameter is defined as the ratio of the total particle surface area to an equivalent amount by weight of spherical particles with a diameter of 1 cm (ILRI, 1974, Boonstra and De Ridder, 1981).

In reality, granular soils are not composed of uniform particles of a single diameter, but still contain grains of varying sizes, to be grouped into fractions, with certain limits of

36

particle size. A relation between fraction size and a U value is given in Table 6.

(6)

where Wj is weight of fraction i and Wtot is the total weight of all fractions

Table 6 Classification of sandy materials, grain size limits and corresponding specific surface (U) (ILRI, 1974).

Description

Silt Very fine sand Fine sand Moderately fine sand Moderately coarse sand Coarse sand Very coarse sand Extremely coarse sand

Particle size limits (micron) d1 d2

16 63 83

125 200 333 500

1000

63 83

125 200 333 500

1000 2000

d in cm

390 140 100 65 40 25 15 7.5

The empirical relationship between hydraulic conductivity (K) and grainsize distribution is that given by (ILRI, 1974, Boonstra and De Ridder, 1981, quoting unpublished research by Ernst).

where U is the specific surface of the main sand fraction Cso is correction factor for the sorting of sand (see Fig. 30a) Cel is the correction factor of particles <16 microns (see Fig. 30b) Cgr is the correction factor for the presence of gravel (see Fig. 30c).

(7)

The correction factor Cso takes into account the sorting of the sand, taken as the percentage by weight of the three neighbouring subfractions with the highest weight percentage.

37

The correction factor Cel takes into account the content of particles less than 16 microns (percentage by weight of dry soil). The method is unreliable for soils having more than 4% particles less than 16 microns.

The correction factor Cgr takes into account the gravel content. When gravel occurs intermixed with the finer particles, it obstructs the flow of water and consequently decreases hydraulic conductivity. Normally, however, gravel occurs as separate layers even though it seems intermixed in disturbed samples. The occurrence of gravel signifies that layers of high hydraulic conductivity are present. In the graph only this factor has been taken into account.

Fig. 30

100

'" c 0 80 C4= .- 0

il'!o Cl./:: .(; g. 60 t .... g",

40 0.4 0.8 1.2 1.6

E correction factor Cso E -0 6 ~

0 d v 4 il'! '" 2 ID (j t 0 0 Q.

0 Q4 0.8 1.2 correction factor C cl

60 E E N 40 /\

il'! ID 20 > f2 Cl

0 1.0 1.4 1.8 2.2

correction factor C gr

Correction factors for estimating hydrauli'c conductivity of sand from grain size distribution expressed in specific surface (U) (ILRI, 1974, Boonstra and De Ridder, 1981).

38

3.3 Porosity and Bulk density

There are a number of different methods which may be used to measure the porosity of earth materials. Many of these directly examine in situ sample material. In boreholes for example it is possible to make accurate measurements of rock porosity by geophysical well logging techniques. Other methods rely on the measurement of the porosity by vacuum extraction of the fluids contained within the pores. Such methods, therefore measures not the total porosity but effective porosity. This is not terribly important since it is the porosity of the interconnected pores which is of significance in an aquifer.

Most commonly in soil physics however, laboratory porosity is determined by oven-drying a fully saturated soil sample of known volume at 105 QC until a constant weight is attained. This is intended to remove soil moisture rather than the water of hydration contained in certain mineral constituents. The total porosity (n) can then be calculated according to

n = 100 volume of water removed during drying (8) total volume of sample

The bulk density is the mass of the sample after oven-drying divided by the original sample volume.

3.4 Permeameter tests

The hydraulic conductivity in earth materials can be determined in the laboratory using permeameters. All permeameters have some kind of container to hold a sediment or rock sample. It is possible to make a permeability analySiS of 'undisturbed samples' from unconsolidated materials if they are left in field sampling tubes or rings, which become the permeameter sample containers (Fetter, 1988). There are two types of perm ea meters, the constant head permeameter which is used for noncohesive, high permeability sediments such as sands and the falling-head permeameter which is more suitable for cohesive, intermediate to low permeability sediments such as clays and silts.

3.4.1 Constant head Permeameter

A constant head permeameter (Fig. 31) is composed of a chamber with an overflow to provide a supply of water at a constant head, so that water moves through the sample at a steady rate. The resulting hydraulic gradient is determined by means of piezometer tubes inserted at different levels. The hydraulic conductivity (k) is determined from a variation of Darcy's law:

VL K=-­Ath

39

(9 )

where V is the volume of water discharging in time t L is the length of the sample A is the cross-sectional are of the sample h is the hydraulic head difference over the sample

Because of small pressure losses which occm within filter layers and possibly in the pipeline connections, the difference between the permeameter inlet and outlet levels can only be used if these additional head losses are small compared to those over the sample. It is also essential that the head should never be more than half of the sample's length to avoid high flow rates and therefore invalidation of Darcy's law (Fetter, 1988).

3.4.2 Falling head permeameter

A falling head permeameter is illustrated in Fig. 32. A falling head tube is connected to the permeameter. The initial water level above the outlet in the falling head tube, ho is noted. After some time period, t (generally several hours), the new water level, h, is again measured. The inside diameter of the falling··head tube, d" the length of the sample, L, and the diameter of the sample, dc, must also be known (Fetter, 1988). The hydraulic conductivity, le, calculated according to

cross-section A

d~L ho K=-ln(-)

d2t h c

(10)

Fig. 31 Constant-head permeameter. Fig. 32 Falling-head permeameter.

40

3.5 Results grain size distributions

3.5.1 Introduction

Several classification systems exist for description of particle size distributions. Figure 33 (after Marshall and Holmes, 1988) illustrates some of these, showing small differences. All systems define clay as particles less than 2 JJ.ID in diameter, while gravel particles are larger than 2000 JJ.ID. However, the boundaries between silt, fine and coarse sand vary between the various classification systems. In the present report the classifications by Massachusetts Institute of Technology (M IT) and the British Standards Institution (BSI) are used.

All data regarding grain size distributions can be found in Appendix E.

100

-0 80 c 0

LL ~~

'H 60 :!la OE silly loam E'"

'" 40 =Q) 0-",0 -t °0 (f!o. 20

0 10

1

MIT medium l' BSI silt

---" ___ ._,, __ .-.L __

gravel

USDA silt v. co. sand '--_...L.

gravel

ISSS L ... __ .. __

Fig. 33

silt fine sand gravel

Particle size analysis, showing cumulative curves for clay, silty loams and medium sand. Three different classification systems are shown on the bar below the figure. In all cases the clay particle size boundary is 2 JJ.ID. ISSS: International Society of Soil Science MIT: Massachusetts Institute of Technology USDA: United States Department of Agriculture BSI: British Standards Institution

41

j'

f It

3.5.2 Field results

A. ORC site

The analysis of the UB/Environmental Sci~nce Laboratory is shown in Fig. 34 (33 samples), while Fig. 35 (29 samples) shows the analysis by the GS Laboratory. Both labs used dry sieving methods, and the silt and clay content may therefore be underestimated in some cases. However, most samples consisted of loose white sand, consisting predominantly of pink and white quartz grains. The figures show no large differences between the laboratories. It should be noted that the samples were not duplicates, they were collected in the same area. The sand may be classified as well-sorted, ranging from fine to medium.

100

"0 c 80 0

..c:E "=~

60 3~ ~o oE E'" :=~ 40 0-<nO -t °0 aQQ. 20

Fig. 34 Cumulative distribution curves ORC site (33 samples, UB analysis). lOO~-------------------~~~~~----~1

"0 c 0

..c:E "=~ 3~ ~O oE E'" =~ 0-<nO ~€ °0 aQQ.

80

60

40

20

o -I----~-~~~ 10' 10

2

effective diameter d (~m) [MT [mediumr:J30arse Gf~--- d I medium'L---coOrSeT--;-;;~l

BSI silt silt Ine san sand sa~~ ___ _____ ___________ ______ __ -.J

Fig. 35 Cumulative distribution curves ORC site (29 samples, GS analysis).

42

B. Beacon Island site

The cumulative distribution curves for the Beacon Island area are shown in Fig. 36. Again the sand may be classified as ranging from fine to medium. Here, however, distinctly coarser layers were encountered than in the ORC site. The reason for this is that the sampling site was right at the Beacon Island inlet point (Din<;er et al., 1976), which is part of an inverted channel bed and which is clearly visible as a meandering sand ridge, slightly elevated above the surrounding flood plains. At a later stage in the Delta's evolution, water ponding against one side of the ridge has broken through at this particular point, thus creating an inlet channel cutting perpendicular across the ridge. The coarser layers clearly indicate a depositional environment with relatively high fluviatiJe energies. This situation is not unlike that in the Shashe River near Maun. The analysis of the top 16 samples from one borehole (PHI, drilled by cable tool methods, Gabaake et al., 1993) is shown in Fig. 37. The cumulative distribution curves of Figs 36 and 37 are remarkably similar. It appears therefore that the Shashe River sands are not exceptional, but fall within the range encountered elsewhere in Delta river environments.

Fig. 38 summarizes the findings of this report with regard to the grain size distributions encountered in the ORC site, Beacon Island and the Shashe River. All particle size distributions fall within the area bounded by the two curves of Fig. 38.

100

1) 80 c 0

.c:S ±=~

3..9! 60 ~O oE E'" =:1) 40 0-"'0 -t °0 ~Q. 20

o~~~~~~~~~--~~~ 10' 102 10

3 10

4

effective diameter d (Ilm)

medium coarse I L-.-=.::'----'---'s"'iltc __ -"-_s,ilt -'-_f_in_e_s_a_n_d_L ___ -'-

Fig. 36 Cumulative distribution curves for the Beacon Island inlet area. The coarse material was found about 4 to 5 m below the inlet point. Grain size distributions of this sand are similar to those encountered in the Shashe River.

43

100

1J c 80 0

LE ±o~

3.!!! 60 ~o oE E'" =~ 40 0-"'0 et aI!~ 20

0

10' 102

103 104

effective diameter d (fLm) MIT medium BSI silt coarse I fine ~nd medium L coarse J -grav~'--l

silt sand sand L-~---.JL-::::':""-_L-.:~-----1 _______ ~ _________ _

Fig. 37 Cumulative distribution curves of the top 16 samples collected from Borehole PHI (Gabaake et ai., 1993). A sample was taken at intervals of 1 m.

l00'---~--------~~~~~=-~~=-------~1

1J 80 c o

LE ""~ 3.!!! 60 ~O oE E'" = Ql 40 ~o 'l-t 0 0 aI! 0- 20

o 10'

fine sand ORC transect flood plain piezometer A

102

medium sand Beacon Island inverted channel bed

effective diameter d (fLm)

medium coarse~ _~'" [ medium I L--=-=,,-__ ,---,-sic:clt_ _L-~si",-It __ L~e s~ sand

coarse -}-9;;;-;eIJ sand ----- "~---.-

Fig. 38 The figure shows the two extreme cumulative distribution curves of sands encountered in the Delta

44

3,!'L3 ComparisOIl DB and CS analysis with particle size analysis by the Soils Laboratory of the Ministry of Agriculture,

To check on the dry sieving procedures, 5 samples were also analyzed by the Soils Science Laboratory (at Sebele) of the Ministry of Agriculture. A full soil chemical analysis was made and the clay content was determined by hydrometer analysis (see App. E for the results). Figs 39 and 40 below compare two of the results with the dry sieving method as implemented at UB. Fig. 39 shows the case where the largest difference between the two laboratories occurred. At Sebele more silts and fines were found in sample 3 which was taken close to the surface (0.10 m depth, flood plain transect ORC site). This is very likely a case where dry sieving does not produce satisfactory results. Surface soils in the Delta are generally higher in organic content, have higher CEC than the more sandy soils below. When augering down from the surface to larger depth, colour and texture changes are clearly noticeable. Fig. 40 shows the comparison for sample 32 (depth 4.70, Beacon Island inlet point, one of the coarSest samples). It is clear that in this case dry sieving produces good results. Fortunately most samples consisted of clear sand.

It should be noted that even small amounts of fines and clays will reduce the hydraulic conductivity considerably. Fig. 30 shows that due to the presence of only 2% clay the conductivity may go down by a factor 2. The particle size analysis by oven-drying and sieving only, will tend to conceal the presence of clays. In the field, however, it is not difficult to determine from colour and texture whether appreciable amounts of clays are present. Determination of conductivity by means of permeameter tests will also reveal the presence of fines and Clays.

"0 c 0

LL ~->-

.~~

~a oE E~ =(3 0·-~o

v.- t 0 0

<I"- D.

Fig. 39

100

80

60

40

20

---,,-----

sample 8 ORC site depth O. 10 m

.--------~~~.-----,

silt and clay content higher (Soils Lab. d1y sieving Min. of AgricuI1'ure) and weighing

~_----- hardly any fines o ... -r--_,---,--,........-rT"T"r-"h~r~~..,--,,------,.---,--,-...... ·~-...,.-,-·~~,...,-,.i

10° 10' 102 10 3 104

effective diameter d (11 m)

Comparison of the particle size analysis by UB (oven·drying and then sieving) with the results of the Soils Lab (Se be le, Ministry of Agriculture) where the clay content was determined by hydrometer analysis. The dry sieving method obscures the presence of fines and clays.

45

"0 c a

..coS "'~ 3~ ~O oE E'" =$ 0-",0 -1: 0 0 ()l!D..

Fig. 40

100

80

60 Soils Lab Min. of Agric.

40

20

0 lo° 10

1 10

2

effective diameter d (flm)

Cumulative distribution curves for a medium sand (Beacon Island, depth 4.70 m). The two laboratory procedures yield the same results.

3.6 Porosity and bulk density.

A total of 40 ring samples were taken with hydraulic equipment, 23 from the Beacon Island site and 17 from the ORC site. This made it possible to determine porosity and bulk density as described in section 3.3. Although this type of work is very simple and belongs to the standard soil physical techniques, it has never been done in the Delta area before. The data may be found in Appendix F and Table 7 summarizes the results for the two sites. For the range of soils studied, the porosity equals 33.0 ±2.5 % while the bulk density averages 1.66 ±D.07 g/ cm3

. Specific yield values therefore have an upper limit of 0.33. They probably range from 0.2-0.3 as is also indicated by the results of the pumping tests. The importance of these results lies in the fact that they have to be used as input data in (a) modelling of groundwater flow in the upper unconfined aquifers and (b) the determination of actual evapotranspiration (when groundwater level recession rates are also monitored).

Table 7 Results of porosity and bulk density determination.

rings porosity bulk density % g/cm3

Beacon Island 23 33.00±2.35 1.6S±D.05 ORC site 17 32.96±2.S9 1.65 ±D.OS

total 40 32.9S±2.64 1.66±D.07

46

3.7 Relation between conductivities determined by the permeameter method and grain size analysis

The soil rings were also used to determine the hydraulic conductivity of the samples by means of the permeameter method described in section 3.4. The results are given in App. F. It is also possible to determine the hydraulic conductivity by grain size analysis as described in section 3.2 through Eqn. 7. As mentioned by ILRI (1974) and Boonstra and De Ridder (1981), the proportionality factor 54000 in relation (7) may have to be adjusted for each depositional environment. The soil ring experiments therefore offer the opportunity to recalibrate the relation against the measured conductivities. Fig. 41 shows a plot of the hydraulic conductivities measured by the permeameter method (~cnn) against those determined by the grain size analysis (kpsa). The calculations are summarized in Tables 8 and 9. Figure 41 shows that the hydraulic conductivity (~sa) considerably overestimates the conductivity in a number of cases. The field and laboratory observations c.learly indicate that this is the case for clayey samples where the method used (oven-drying and sieving) is not valid. Therefore all samples with ~enn < 2 m/day were taken out of the regression analysis. It was then found (Fig. 42) that good correlation may be achieved by adjusting the proportionality factor down from 54000 to 19880, which may be rounded off to 20000. Relation (7) then becomes

c c C k - 20000 so cl gI

psa -U2

( 11)

Since the correction factor for gravel content (Cgr) was 1.00 in all cases (see Tables 8 and 9), this factor may perhaps be left out from (11).

Finally, it should be noted that the analysis is only valid for sand samples with k> 2 m/ day. Care should be taken not to apply the relation in cases where clay is suspected from sample colour and texture, and where only dry sieving methods can be used.

Fig. 41

lO'~-----------------------------o Beacon Island o ORCs~e

• • ••

o •

o

o • •

• 0 ·-iP ,&. 00 • ~8 .,

10-' 10-' lo° 10' k permeameter (m/day)

10'

Plot of hydraulic conductivities from permeameter tests against those determined by grain size analysis.

47

102 ~---------.-----.----

r = 0.90

fador 19880

o o rf> g

<P o ,

o o

o o

o o

o o

o o 0 0<f; 0 0

o

o

-~---------.. -.-----' 10' '10

2

k perrnearne"ter (rDJ day)

Final correlation between le perm and y,v'" uc;ing a proportionality factor of 20000 (Eqn, 11),

48

Table 8 Calculation of hydraulic conductivities through Eqn. 7 (samples 32-52).

repack 3.2 1.1 1.2 1.3 1.4 3.1 repack 3.6 3.7 4.1 4.3 4.12 4.14 4.16 4.20 5.1 5.3 5.5 5.7 5.9 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Ui % % % % % % % % % % % % % % % % % % % % >2000 0.13 0.02 0.00 0.00 0.00 0.03 0.00 0.14 0.00 0.00 0.00 0.10 0.02 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1000·2000 7.50 3.52 0.13 0.28 0.39 0.36 0.46 0.15 3.54 0.20 0.17 0.12 0.43 0.17 0.12 0.14 0.28 0.22 0.26 0.18 0.13 0.12 500·1000 15.00 22.38 1.38 4.26 4.52 3.74 4.26 4.08 22.28 3.60 3.09 2.72 2.91 2.74 2.80 2.66 2.91 4.03 3.61 2.96 1.56 1.85 355·500 24.08 41.75 5.56 15.56 15.06 12.93 13.83 7.87 41.84 12.07 10.13 11.58 7.08 11.41 12.73 10.17 6.09 14.36 13.21 11.91 6.25 8.00 250·355 34.08 15.26 16.34 28.99 27.39 24.17 34.63 18.79 15.57 24.16 21.73 20.53 13.08 22.02 23.31 19.07 10.53 27.34 25.77 24.76 16.77 23.76 180·250 47.78 6.77 20.83 21.33 20.83 19.97 30.39 21.69 6.55 23.74 23.08 16.45 13.01 16.82 16.00 15.73 11.67 23.29 23.46 23.66 23.91 29.60 106·180 74.95 8.91 47.26 23.39 24.55 29.22 15.13 38.30 9.00 30.11 34.42 37.36 46.65 34.99 34.08 40.06 50.75 23.07 24.82 27.06 39.60 30.51 53·106141.51 1.13 7.46 4.95 5.48 7.38 1.02 7.42 1.05 4.59 5.70 9.82 14.49 10.52 9.29 10.71 15.37 5.05 5.46 6.11 9.30 5.15

15·53 427.67 0.09 0.32 0.81 1.08 0.62 0.14 0.96 0.03 0.93 1.01 1.06 1.44 0.91 1.06 1.08 1.45 1.55 1.46 2.13 1.58 0.59

<15 0.06 0.69 0.45 0.70 1.61 0.10 0.74 0.01 0.59 0.67 0.36 0.80 0.41 0.56 0.39 0.95 1.07 1.95 1.22 0.91 0.42

topf 79.40 84.44 73.70 72.77 73.36 80.16 78.78 79.68 78.01 79.23 74.34 74.16 73.82 73.40 74.86 77.80 73.71 74.05 75.48 80.27 83.87 Us 30.76 64.43 52.46 54.39 56.46 43.69 62.58 30.47 56.06 59.53 64.51 74.48 63.71 62.31 66.68 77.09 55.60 56.32 61.10 68.48 57.14

corgrav 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 corsort 1.26 1.40 1. 10 1.10 1. 10 1.27 1.24 1.27 1 .21 1.23 1.10 1.10 1.10 1. 10 1.12 1.20 1. 10 1. 10 1. 14 1.27 1.40 core Lay 0.97 0.85 0.87 0.82 0.65 0.97 0.84 0.98 0.85 0.84 0.90 0.84 0.88 0.86 0.88 0.79 0.73 0.58 0.72 0.77 0.86 ..,.

repack 3.2 1.1 1.2 1.3 1.4 3.1 repack 3.6 3.7 4.1 4.3 4.12 4.14 4.16 4.20 5.1 5.3 5.5 5.7 5.9 \0 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Kpsa 69.77 15.48 18.78 16.47 12.11 34.85 14.36 72.40 17.67 15.74 12.84 9.00 12.88 13.16 11.97 8.61 14.03 10.86 11.87 11.26 19.91 Kperm 19.18 4.8 4.77 5.5 3.87 20.24 0.83 19.180.0044 0.001 2.47 2.44 7.89 3.86 2.85 3.17 3.34 3.46 1 .21 3.64 12.7

Note The analysis of samples 32 and 39 refers to an experiment where a ring was repacked with sand after the grain size anaLysis (32). The sample was then re-analyzed (39).

"'.~_w, ':-'::itf.,'._:.,::.:","" ',S L~,~" ,--,",",."".",-, ";;:;;;;';;·:1"':':;;";S:''''i:''=''''''''~'-!i'i''''01';''"I:'': .",:",:,.',3

Table 9 Calculation of hydraulic conductivities through Eqn. 7 (samples 53-72).

A1 A2 A3 A4 C2 F1 F2 F3 F4 C1 BC1 BC2 BC3 G1 G2 H1 H2 11 12 J1 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72

% % % % % % % % % % % % % % % % % % % % >2000 Ui 0.03 0.01 0.03 0.00 0.00 0.00 0.09 0.13 0.05 0.00 0.27 0.01 0.19 0.06 0.00 0.00 0.01 0.01 0.01 0.01

1000-2000 7.50 0.20 0.13 0.06 0.05 0.03 0.31 0.50 0.76 0.69 0.06 2.81 1.05 1.76 0.38 0.05 0.16 0.29 0.27 0.23 0.41 500-1000 15.00 1.88 1.25 0.54 0.30 0.42 4.47 3.94 5.22 4.93 1. 17 10.99 13.01 12.80 5.72 0.77 1.62 5.71 3.00 6.39 4.21 355-500 24.08 6.10 4.20 1.98 1.51 1.84 15.39 10.95 13.83 13.91 4.55 22.30 44.11 39.97 13.96 6.23 5.12 13.13 9.79 17.97 11.78 250-355 34.08 15.70 11.98 7.47 11.44 9.65 27.12 23.62 26.31 26.49 16.22 37.06 30.56 25.96 23.44 37.55 15.54 23.52 21.38 26.21 22.12 180-250 47.78 24.54 23.67 20.52 41.19 34.98 21.76 24.40 23.93 23.50 35.57 18.21 5.09 9.69 20.60 36.28 30.61 27.39 23.68 20.69 20.56 106-180 74.95 45.00 51.62 61.45 42.27 44.48 21.67 27.12 22.74 23.11 32.52 7.70 4.67 8.17 26.02 16.35 38.46 21.66 29.90 18.49 28.53 53-106 141.51 5.41 5.93 7.13 2.85 6.22 5.48 6.67 5.13 5.32 5.97 0.56 1.33 1.25 7.12 2.20 6.77 5.32 8.73 6.32 9.91

15-53 427.67 0.66 0.62 0.47 0.20 0.97 1.80 0.67 1.06 1.13 2.20 0.06 0.09 0.15 1.17 0.31 0.63 1. 19 1.39 2.43 1.57

<15 0.47 0.58 0.35 0.19 1.42 2.00 2.03 0.87 0.88 1.74 0.04 0.07 0.07 1.52 0.25 1. 10 1.78 1.87 1.27 0.90 topfr 85.24 87.28 89.44 94.90 89.11 70.55 75.14 72.98 73.10 84.31 77.57 87.68 78.72 70.06 90.19 84.61 72.57 74.95 65.39 71.21

U 63.04 66.36 71.07 60.58 66.80 55.75 55.62 53.44 54.06 66.03 35.37 31.28 33.70 56.67 48.45 62.52 54.00 62.13 57.30 62.99 corgrav 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 corclay 0.85 0.83 0.92 0.95 0.65 0.57 0.57 0.78 0.77 0.60 0.98 0.96 0.96 0.65 0.94 0.75 0.60 0.58 0.70 0.77 corsort 1.43 1.50 1.60 1.70 1.60 1.00 1.12 1. 10 1.10 1.40 1.20 1.50 1.20 1.00 1.60 1.45 1.07 1.14 0.87 1.03

A1 A2 A3 A4 C2 F1 F2 F3 F4 C1 BC1 BC2 BC3 G1 G2 H1 H2 11 12 J1 K 16.52 15.27 15.74 23.77 12.58 9.90 11.14 16.23 15.65 10.40 50.75 79.48 54.78 10.93 34.60 15.02 11.89 9.25 10.02 10.80

V> Kperm 7.15 7.59 8.64 6.57 2.98 9.70 6.18 10.87 7.71 21.43 35.41 30.14 0.05 10.35 1.95 0.25 3.26 0.02 3.48 0

3.8 Applications

Relation (11) can be used to calculate hydraulic conductivities of the entire grain size distributions data set, thus extrapolating the laboratory determination of the conductivity by means of the permeameter method. Three applications are discussed below as examples:

1. The Shashe Wellfield upper unconfined aquifer 2. The Beacon Island site 3. The transect on the flood plain of the ORC site

3.8.1 The Shashe Wellfield upper unconfined aquifer

The Shashe Wellfield is the major source of groundwater for Maun. First boreholes were drilled in the early 1980s. The increasing water demand of Maun and the lack of outflow from the Delta, led to rapidly dropping groundwater levels, and therefore forced several extensions of the wellfield. The aquifer was first studied by the BR GM (1984) while later several pilot boreholes were drilled by Gabaake et al. (1993) to study the resource further. Many more holes were drilled during the Maun Groundwater Development Project (MGWDP, 1997) and a regional aquifer computer model was prepared. An artificial recharge experiment was also conducted and modelled during the latter project. During these modelling exercises, however, it became clear that basic data with regard to conductivity k, specific yield Sy and porosity n, were only derived from short duration pumping tests, which were not really adequate to derive a conclusive set of parameters for the upper unconfined aquifer.

With the methods discussed in this report, it is possible to provide valuable additional information. As an example, Eqn 11 is used to calculate hydraulic conductivities from the grain size distributions of pilot borehole PHI (Gabaake et aI., 1993). The calculations are given in Table 10. It should be noted that Eqn. 11 was derived for the grain size intervals shown in Tables 8 and 9. Because this analysis requires two intervals (15-65 J.!!ll, < 15 Mm) and Gabaake et al. (1993) only give the fraction < 65 J.!!ll, it was necessary to split this fraction into the two required intervals. This was simply done by separating the < 65 J.!!ll fraction into two equal halves. Tables 8 and 9 show that this is not unreasonable. Normally it would of course be important to determine the clay content accurately, because the correction factor CeI (Fig. 30, page 38) depends on this. The correction factor C?f for gravel content was 1 for all samples, while the correction factor Cso for the sorting ~total percentage in the 3 adjoining top fractions) could be estimated adequately from the data.

The results are shown in Fig. 43, where kpsa is plotted as a function of depth. The horizontal conductivity can be evaluated by

(12)

51

where all di are 1 m, and d = 16 m. The vertical hydraulic conductivity can be calculated as

k = d v 16 d

L---2. 1=1 k i

(13)

Through these equations kh is found to be 9 m/day, while le.. is about 6 m/day. The horizontal transmissivity in the profile is 150 m2

/ d. Fig. 43 shows the layering of the upper unconfined aquifer with both fine and medium sand layers. At a depth of 12 m a layer with low conductivity is encountered.

Because of the similarity of the Shashe Wellfield sand with the samples collected from the ORC and Beacon Island sites, it seems advisable to take the porosity as 0.32 and the specific yield values in the range from 0.2-0.32.

The conductivity values agree rather well with the results of the artificial recharge modelling (MGWDP, 1997). In view of the importance of correct specific yield values for artificial recharge storage projections, it is suggested to carry out some more soil physical work in the area in the future.

o

4

E 8 ~

t <D lJ

Fig. 43

12

16

20 o 10

conductivity profile PH1 Shashe Wf Maun

20 k psa (m/day)

30

Hydraulic conductivity derived from grain size .distributions, plotted against depth for pilot bore hole PHI (Shashe Wellfield, Maun).

52

Table 10 Calculation of hydraulic conductivities for borehole PHI (top 16 m). The data for this borehole can be found in Gabaake et al. (1993). ~sa was calculated by Eqn. 11.

DWAPHl u 2 3 4 5 6 7 8 9 10 11 12 13 1£. 15 16 >2000 0 0 0 Q 0 0 0 0 0 0 0 0 0 0 0 0

2000-1000 7.50 0.07 0.21 1.01 0.84 0.87 0.60 1.25 1.40 0.94 0.49 0.96 1.40 2.29 1 .M 2.50 2.62 1000-500 15.00 0.74 2.07 1.52 2.50 6.96 2.72 10.93 15.96 13.74 4.51 5.71 2.32 4.89 4.21 5.91 3.2l) 500-355 24.08 2.34 6.10 4.17 7.18 34.74 10.89 26.42 36.97 36.37 15.90 16.38 5.80 8.76 9.84 13.94 8.19 355-250 34.08 8.29 13.65 17.71 13.93 37.01 28.49 23.47 21.68 22.58 43.97 34.46 11.90 15.63 19.89 25.30 17.18 250·180 47.78 34.11 28.54 47.31 17.24 10.67 33.61 17.64 4.06 11.86 27.16 23.95 27.09 33.25 28.72 27.42 32.76 180-125 67.78 39.06 36.92 26.69 56.17 8.24 16.23 12.45 10.64 8.43 5.91 10.51 29.65 27.60 27.16 19.09 22.81 125-65 116.92 14.52 11.79 1.33 2.05 1.39 5.72 5.87 8.05 4.89 1. 16 4.58 12.81 6.72 7.13 4.77 9.22 65-15 410.26 0.44 0.36 0.13 0.05 0.06 0.87 1.00 0.63 0.60 0.50 2.00 5.00 0.50 0.72 0.53 2.00

<15 0.43 0.36 0.12 0.05 0.06 0.87 0.97 0.63 0.6 0.41 1.45 4.03 0.37 0.72 0.53 1.98

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.01 100.00 100.00

topf, 87.69 79.11 91.71 87.34 82.42 78.32 67.53 74.60 72.68 87.03 74.80 69.55 76.48 75.77 71.82 72.75 U 65.06 60.37 50.13 55.82 34.M 50.10 43.92 39.93 38.14 39.91 48.74 74.44 52.84 53.32 46.85 58.60

corgrav 1.00 1.00 1.00 1.00 1.00 1.00 1. 00 1.00 1.00 1.00 LOO 1.00 1.00 LOO 1.00 1.00 corclay 0.87 0.9 0.98 1 1 0.8 0.78 0.85 0.86 0.9 0.65 0.3 0.88 0.82 0.85 0.57

v, corsort 1.5 1.25 1.65 1.5 1.33 1.23 0.93 1.1 1.08 1.5 1. 12 1 i. 14 1.13 1.03 1.04 w

depth 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 k 6.17 6.17 12.87 9.63' 22.16 7.84 7.52 11.73 12.77 16.95 6.13 1.08 7.19 6.52 7.98 3.t,5

3.8.2 Beacon Island inlet channel

As discussed before on page 43, the inlet channel intersects a palaeo-river channel (see Ringrose et al. 1998), which now lies on the surface as a low meandering sand dune, clearly visible on aerial photographs and Landsat imagery. Because the samples were taken from the former river bed, it is not surprising that some of the coarsest sands were encountered here. Table 11 summarizes the calculations, while a plot of k vs depth is shown in Fig. 44. Conductivity values as high as 30 m/day are found about 4 m below the surface. Also shown is the difference between the conductivity values ~rm' determined through the permeameter tests and ~sa' determined from the grain size analysis using Eqn 11. For these particular points ~erm seems to be slightly higher than ~sa'

Finally, because the palaeochannels show up quite clearly on aerial photographs and satellite imagery, they would potentially be good targets for future hydrogeological investigations. Closer to Maun such palaeochannels are probably also present below the surface. Unfortunately there do not seem to be good geophysical methods for detecting such features efficiently.

0

-1

-2 ~

E ~

r. D. -3 (j)

1J

-4

-5

-6 0

Fig. 44

• permeameter 0 grain size analysis

10 20 30 40 k (m/day)

Hydraulic conductivity as a function of depth (Beacon Island, inlet channel). The high hydraulic conductivity, is caused by layers of uniform medium sand in a palaeochannel.

54

Table 11 Calculation of conductivities for Beacon Island inlet point

gapcon2 G1 G2 G3 G4 G5 G6 G7 G8 G9 20 21 22 23 24 25 26 32 27

depth 0 0.5 1.4 2.2 3 3.7 4.2 4.7 4.8

>2000 0.00 0.00 0.00 0.03 0.08 0.00 0.08 0.13 1.61

1000 0.21 0.29 0.31 0.53 0.93 0.11 0.67 3.52 3.71 500 5.57 4.14 3.98 4.93 4.54 1.14 9.57 22.38 11.10 355 23.07 14.23 12.17 15.67 17.16 10.34 41.30 41.75 26.91 250 35.13 26.70 24.30 34.58 46.17 52.51 29.80 15.26 24.54 180 18.32 22.69 23.40 30.84 21.69 27.48 8.02 6.77 15.81 106 13.92 25.44 28.81 12.60 8.12 7.84 8.95 8.91 13.83

53 2.41 5.20 5.62 0.68 1.12 0.50 1.39 1.13 1.99 15 1.00 0.87 0.92 0.10 0.11 0.06 0.15 0.09 0.40

<15 0.37 0.44 0.51 0.03 0.08 0.02 0.06 0.06 0.11

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

topfr 76.51 74.83 76.50 81.09 85.02 90.33 80.67 79.40 67.26 U 43.50 50.92 52.87 40.84 38.25 39.85 33.72 29.82 37.66

corgrav 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 corclay 0.90 0.90 0.88 1.00 0.98 1.00 0.99 0.99 0.97 corsort 1.12 1.10 1.12 1.26 1.40 1.60 1.25 1.25 0.90

depth 0.00 0.50 1.40 2.20 3.00 3.70 4.20 4.70 4.80 kpsa _10.65 7.64 7.05 15.11 18.76 20.15 21.76 27.82 12.31

3.8.3 Transect on the flood plain of the ORC site.

Six piezometers were installed on a flood plain transect in the Chiefs Island ORC site (Fig. 2, page 4, Fig. 8, page 13, Plate 10, page 14) and 23 bulk and ring samples were collected during installation. All data were converted into conductivity values and the results are summarized in Tables 12, 13 and 14, while k vs depth plots are shown in Figs. 45, 46, 47 and 48. Conductivity values range from 5 m/day near the surface to about 10 m/day at depths of 3 to 4 m. Fig. 46 shows the kpsa and ~rm results for the UB analysis and the ~sa results for the GS analysis. This last analysis overestimates the conductivity values, because different size intervals were used (compare Tables 12 and 13). The 355 J.1ffi sieve was not used in the GS analysis which probably leads to overestimation of the sorting correction factor.

The data collected for this transect are vital input data for future modelling of the surface and groundwater interaction at this particular location.

55

Table 12 Calculation of conductivities for sites 1 (forest edge, piez 1), 7 (plain, piez 2), 14 (main channel, piez 3) and 17 (road, piez 4) of the main flood plain transect (see Fig. 2).

trans2 T1.1 T1.2 T1.3 T1.4 T7.1 T7.2 T14.1 T14.2 T14.3 T14.4 T17.1 T17.2 T17.3 1 2 3 4 5 6 8 .9 10 11 13 14 15

depth 0.05 1.25 2.95 3.8 2 2.75 0.1 0.9 2.05 3 0.85 2.15 3.75

>2000 0.01 0.00 0.11 0.00 0.00 0.00 0.00 0.06 0.00 0.10 0.00 0.00 0.00

1000 0.28 0.50 1.57 0.13 0.05 0.02 0.22 0.30 0.26 1.09 0.16 0.02 0.01 500 5.87 10.99 10.72 2.79 1. 11 0.31 3.61 10.17 2.97 4.81 10.26 0.21 0.18 355 18.49 22.46 26.61 13.87 4.37 1.92 10.73 15.61 8.20 13.91 12.45 0.64 0.85 250 23.78 23.08 35.73 41.82 13.20 14.87 23.48 23.83 22.58 37.53 21.85 6.96 11.26 180 17.81 15.87 13.57 28.49 22.40 36.77 25.95 23.30 31.67 27.93 26.63 25.90 47.39 106 23.36 20.13 9.09 11.09 51.60 43.57 29.41 21.43 30.51 12.69 24.08 58.98 38.92

53 7.12 5.39 2.19 1.37 6.45 2.22 5.00 3.38 2.93 1.30 3.24 6.56 1.22 15·53 1.87 0.99 0.23 0.19 0.39 0.13 1.20 0.44 0.32 0.38 0.70 0.45 0.11

<15 1.42 0.59 0.18 0.25 0.43 0.20 0.38 1.47 0.55 0.27 0.62 0.27 0.06

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

topfr 64.95 61.41 75.91 84.18 87.20 95.20 78.84 68.57 84.77 79.37 72.57 91.85 97.57 V> u 57.52 49.50 37.68 42.71 65.90 59.49 57.81 47.28 53.66 43.25 50.34 70.36 58.06 0\ corgrav 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

corsort 0.87 0.78 1.10 1.40 1.54 1.80 1.20 0.96 1.40 1.25 1.00 1.65 1.80 corctay 0.75 0.88 0.95 0.93 0.90 0.96 0.88 0.65 0.85 0.93 0.84 0.93 0.97

depth 0.05 1.25 2.95 3.8 2 2.75 0.1 0.9 2.05 3 0.85 2.15 3.75 kpsa 3.94 5.60 14.72 14.28 6.38 9.76 6.32 5.58 8.26 12.43 6.63 6.20 10.36

Table 13 Calculation of conductivities for samples 73-78 on the main flood plain transect (Analysis by GS).

TRGSl 73 74 75 76 77 78 sampLe Al A2 A3 A4 AS A6

depth (m) 0.98 1.19 1.59 2.01 2.63 3.50

<15 0.45 0.60 0.40 0.30 0.20 0.05

15·63 412.70 0.45 0.60 0.40 0.30 0.20 0.05 63-125 119.37 11.20 11.00 11.20 9.80 7.10 2.40

125·250 60.00 63.40 61.40 67.50 71.30 75.10 54.60 250-500 30.00 22.10 24.10 18.70 17.40 17.00 41.90

500-1000 15.00 2.10 2.00 1.60 0.80 0.30 0.90 1000-2000 7.50 0.30 0.30 0.20 0.10 0.10 0.10

>2000 0.00 0.00 0.00 0.00 0.00 0.00

100.00 100.00 100.00 100.00 100.00 100.00

topfr 96.70 96.50 97.40 98.50 99.20 98.90 u 60.23 60.00 61.39 61.06 59.51 48.54

corgrav 1.00 1.00 1.00 1.00 1.00 1.00 corclay 0.88 0.83 0.89 0.91 0.93 0.98 corsort 1.80 1.80 1.80 1.90 1.90 1.90

73 74 75 76 77 78 Al A2 A3 A4 AS A6

kpsa 8.73 8.30 8.50 9.27 9.98 15.80 depth 0.98 1.19 1.59 2.01 2.63 3.50

57

Table 14 Calculated and measured conductivities for piezometers 1, 2, 3 and 4 on the flood plain transect.

piezometer 1 (forest edge, site 1)

sample depth kpsa analysis (m) (m/day)

1 -0.05 3.94 UB 2 -1. 25 5.60 UB 3 -2.95 14.72 UB 4 -3.80 14.28 UB

piezometers 2 and A (Srn South of piezometer 2), flood plain

sample depth kpsa kperm analysis (m) (m/day) (m/day)

73 -0.98 8.73 GS 53 -1.03 6.11 7.15 UB 74 -1.19 8.30 GS 75 -1.59 8.50 GS 54 -1.67 5.65 7.59 UB

5 -2.00 6.38 UB 76 -2.01 9.27 GS 55 -2.11 5.82 8.64 UB 77 -2.63 9.98 GS 56 -2.73 8.79 6.57 UB

6 -2.75 9.76 UB 78 -3.50 15.80 GS

piezometer 3 (site 14) , main channel

depth kpsa analysis (m) (m/day)

8 -0.10 6.32 UB 9 -0.90 5.58 UB

10 -2.05 8.26 UB 11 -3.00 12.43 UB

piezometer 4 (site17) , next to main track

depth kpsa analysis (m) (m/day)

13 -0.85 6.63 UB 14 -2.15 6.20 UB 15 -3.75 10.36 UB

58

0,---,,---------------------------, piezometer 1 (forest edge)

-1

~

g -2

t Ql

U

Fig. 45

~

E ~

J:

1i Ql u

Fig. 46

-3

-4

-5+-----------~----------~--------~ o 10 20 30

k (m/day)

Conductivity as a function of depth for piezometer 1 (forest edge).

0,-------------------------------------,

-1

-2

-3

-4

o * • •

• * 00

piezometers 2 and A (flood plain)

• GS grain size analysis o UB grain size analysis * UB permeameter

•

-5+------------,------------r-----------~

o 10 20 30 k (m/day)

Conductivity as a function of depth for piezometers 2 and A (A is 5 m south of 2 along the transect. Three different sets of values are shown: the ~sa from the GS analysis, the ~sa from the UB analysis and the k""rm from the UB perm ea meter analysis. The GS analysis probably feads to overestimation because of different class intervals.

59

o~----~---------------------------, piezometer 3 (main channel)

-1

g -2

t ID 1J

-3

-4

-5+-----------~----------~--------~ 30 20 o

Fig. 47

10 k (m/day)

Conductivity as a function of depth for piezometer 3 (in the main channel).

o~------------------------------------,

-1 .

~

g -2

t ID 1J

-3 -

-4

piezometer 4 (main track)

-5+-----------~------------~----------~ 30 o

Fig. 48

10 20 k (m/day)

Conductivity as a function of depth for piezometer 4 (along the main track on Chiefs Island.

60

4 Major ion chemistry

4.1 Introduction

Although a thorough hydrochemical study was not a main objective of this field project, it was felt useful to include an analysis of surface water and groundwater chemistry in order to contribute to the baseline data collection programme of the ORC site. Many studies are available with regard to the Delta's hydrochemistry, for example Hutchins et a!. (1976), Sawula et a!. (1992), McCarthy and Ellery (1994, 1995), Cronberg et a!. (1996) and the MGWDP (1997).

It was already recognised by Hutchins et a!. (1976) that Ca2+, Mg2+ and HC03- are the dominant ionic species in the surface waters of the Okavango Delta. A detailed analysis of trace elements in the waters of Boro River was made by Sawula et a!. (1992). Their results showed that Cu, Fe and Zn are common in suspended matter while Mn occurs mainly in solution. The relative amounts of Zn and Cu decreased slightly downstream while Fe and Mn increased. This feature was explained by an increase of suspended load as the water progresses through the system.

Detailed surface water major ion chemistry of the Jao/Boro river system was analyzed recently by Cronberg et a!. (1996). They observed that the important chemical features of the surface waters were moderate ionic content and high dissolved silicon content, and that differential removal of ions by chemical precipitation is necessary in maintaining the freshness of the waters. As a result the ionic spectrum of the waters shifts from calcium-sodium-bicarbonate at the inflow to sodium-calcium-bicarbonate in the distal areas. Furthermore, they observed that pH of waters varied from neutral to slightly alkaline in distal areas, and alkaline in pools and ponds which are hydrologically isolated from surrounding waters for most of the year.

4.2 Materials and methods

Water samples were taken from the floodplain and piezometers throughout the study area. Field measurements were taken for the main physicochemical parameters such as temperature, electrical conductivity (EC) and pH, using meters calibrated against standard KCl solutions and pH buffers. In addition to these measurements, nitrate and nitrite were determined using a hydrochemical field kit. During each sampling episode, an aliquot of one litre of water in a plastic polyethylene bottle was taken for determination of major cations and anions. A volume of 250 ml with the addition of 1.75 ml of 55% nitric acid was used for the analysis of Na +, K+, Ca2+ and Mg2+. The samples were acidified to prevent precipitation. The one litre (non-acidified) samples and acidified 250 ml samples were analysed at DGS-chemistry and UB-chemsitry laboratories respectively.

At DGS-chemistry laboratory anions were analysed by a Dionex-lOO Ion Chromatograph. The cations were measured using an Atomic Absorption Mass spectrometer (SpectrAA-20). The UB-chemistry analysis program involved cation analysis of the pre-acidified samples using the same type of instrument. The data are contained in Appendix G.

61

4.3 Results and discussion

4.3.1 Analysis of data

Fig. 49 shows the comparis'On between analyses of major cations (Ca2+, Na+, K+ and Mg2+) made by DGS-Chemical Laboratory and UB-Chemical Laboratory. Note that water samples analysed by the UB-Chemical Laboratory were pre-acidified with 55% nitric acid. Good correspondence was found for the cations Na+ K+ Mg2+, but not for Ca2+. The GS Chemical Laboratory results for Ca2+ were consistently higher than those of the VB Chemical Laboratory. This is surprising because it was expected that, if there were differences, the cation concentrations in the pre-acidified samples would be higher than in the non-acidified samples. The difference is not understood at present. Because,

the electrical balance of the GS analysis was good, it was decided to accept the Ca2+ concentrations of the GS Laboratory.

4.3.2 Hydrochemical trends

Fig. 50 shows a Piper diagram for all piezometer holes and surface water considered in the study area. while Table 15 contains the concentrations (meqjl) of the major anions

Fig. 49

20 -f-_.-'--_L ~-'-......-' _..1..- .-1-_--1..1 ... _.l....... ..L...---;1/ ~

16

~ .50 (\] 12 -(\] '0

E Q) .r:. '-< 8 (/J C) Cl

4

+

+ -tt-

+

+

/ /

/ /

/

/0' + / .' /.~

/ /

/ /

/ /

/ /

/ /

/

/+ /

/

+ Ca 2+ 0 Na+

• K+

• Mg2+

Theoretica!!ine

o -t'-..,--,---,---,I--,----r-,'---,--"l o 4 8 12 16 20

U B-Chem data in mg!!

Comparison of the cation analysis by the GS and VB Chemical Laboratories. The GS samples were non-acidified (1000 ml samples), while the UB samples were pre-acidified with 1.75 ml of 55% nitric acid (250 ml samples). Note the discrepancy for Ca2+.

62

Table 15 Major ion composition of surface water and groundwater at the ORC site (units meq/l).

gw piez

hole A

C03 0.0000 HC03 1. 6230

Cl 0.1944 S04 0.0000 N03 0.0839

Bum 1.9012

K 0.1846 Na 0.3478 Ca 0.9500 Mg 0.4082

sum 1.8906

%dev 0.28

80

Fig. 50

gw gw gw gw surface surface piez piez piez piez gauge weir

C F G J R2 R1

0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1. 5246 0.9016 1. 0492 1. 0820 0.8033 0.7213 0.1155 0.2254 0.1972 0.1155 0.1944 0.2310 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0935 0.0000 0.0000

1. 6401 1.1270 1. 2464 1.2910 0.9976 0.9523

0.1564 0.2564 0.2769 0.3487 0.2051 0.2256 0.3478 0.3043 0.3043 0.3913 0.3043 0.3043 0.9000 0.4000 0.4500 0.2500 0.4000 0.3500 0.3265 0.1633 0.2449 0.2449 0.1633 0.1633

1. 7308 1.1240 1.2762 1.2349 1.0727 1.0433

-2.69 0.13 -1.18 2.22 -3.63 -4.56

legend

<& 'b Ii'l piezometer A

0 8l piezometer C g ~

.§~ % • piezometer J

if 'b'" 0 piezometer G , \ piezometer F ,!' 0 .p 00 ~t surface/weir sQ. -$' • ,

'" 0 surface/gouge

R '&

0

'b 8l R eft!

<§> 'b 'b " ,!' R '& '0 0

9; 0"

"" -2 I!

'b < t " 'b'0, "s. " ~ '\ ,

%, ,!' <s> f! ..

'b"? 0 ,9 'b if 0

fil 0 • '& <§> 'b ~

60 40 20 20 40 60 80 calcium chlorine

Piper diagram of major anion and cation concentrations of the surface water samples (circles) and groundwater samples (squares). The concentrations in meq/l can be found in Table 15.

63

and cations. Fig. 50 indicates that the groundwater composition is very similar to that of the surface water, as is to expected in an area with regular seasonal flooding. Figs. 51 and 52 indicate which changes occur to the infiltrating surface water. First of all the total ionic content of the water increases as is clearly shown in Fig. 51. The EC of the groundwater samples is on average 60 tB/cm higher than the EC of the surface water. Fig. 52 shows that this increase is mainly due to a rise in the Ca2+ and HC03_

concentrations.

The bicarbonate concentration of the groundwater ranges from 0.7 to 1.6 meq/I, whereas the chloride varies between 0.11 and 0.23 meq/L The sulphate content is generally very low. Furthermore, calcium content ranges from 0.25 to 1 meq/I and magnesium concentration is between 0.16 and 0.41 meq/L Also, the sum of the sodium and potassium concentrations ranges from 0.5 to 0.7 meq/I/.

2oo,----------------------------~-,

E 0. ,s, 100

cs J-

TDS=O.73EC

C e

gauge • G

~weir

eA

e groundwater ° surface water 0+0C----r----,-----,----.-----r--~300

100 200

Fig. 51

5. Conclusions

EC (~S/cm)

EC (tB/cm) plotted against TDS (ppm). Note the increase in EC and TDS between surface water and groundwater.

A technique was developed to install piezometers cheaply and efficiently to depths 2 to 3 m below the water table. This type of piezometers is of great value to the study of surface water and groundwater interaction in the Delta area. Further technical experiments should be conducted in future to reduce the diameter of the piezometer pipes, while using electronic data loggers to facilitate long-term monitoring in this remote area.

The network of piezometers in the ORC site on Chiefs Island is the first of its kind in the Delta. The long-term monitoring should enable accurate water balance studies in this area in the near future. It will make it also possible to study actual evapotranspiration by plants and trees, which is of great value to biological and ecological studies in the area.

64

2

"" groundwater "- piezometers 0-m A,C, F,G andJ E ~

c :2 !2 +-c m 0 c 0 0

0 0 I 0 '" Z A Z 0 ;;: 0", 0 ° ° + Q Q co'"

",0, b'" ",' + '" "', + +

2

"" surface water "- gauge and weir 0-m E ~

c 0

:;:::

B c m 0 c 0 0

0 0 I 0 '" Z A Z 0 ;;: 0", 0 ° ",0, + Q Q co",

",0, b'" + '" "', + +

Fig, 52 Plot of the major anion and cation concentrations (meq/l) against the ionic species, The top diagram shows the concentrations in groundwater, while the bottom diagram shows those in surface water in the area,

The study of grain size distributions showed that Delta sands mainly consist of fine to medium sands (BIS and MIT classification system), The comparison with sands found in the Shashe River (Ma un) showed that the range of sands encountered in this river bed is entirely within the range of Delta sand samples found thus far. The coarsest sand samples found in the Delta area thus far, originate from palaeo-river channels which can easily be identified by aerial photography and remote sensing techniques.

The study of hydraulic conductivity by means of grain size analysis and permeameter methods, led to an adjustment of the relation given in the literature which resulted in the following expression

65

(14)

which makes it possible to obtain hydraulic conductivity estimates from Delta grain size distributions. Relation 14 is valid for k values greater than 2 m/d. The presence of clay complicates the analysis and great care should be taken to determine accurate clay contents of the samples.

The type of soil physical work described in this report, could also be applied to the potential artificial recharge sites in the Shashe Wellfield. Good field values for horizontal and vertical hydraulic conductivities, specific yield and porosity are extremely useful for modelling the artificial reCharge experiments, and storage projections for management purposes.

Small scale pumping tests have been performed with a submersible electrical pump, while the analysis was done with findings from most recent literature (Moench, 1996, 1997). The results show that composite tests with multiple boreholes yield the best results. The technique should be improved in future by installing piezometers with short screens at various depths in the aquifer and at various distances from the pumped hole.

To make more progress in the understanding of the Delta's aquifers better geomorphological and sedimentological descriptions are urgently required. Coring of undisturbed samples with a drilling rig like the one used in the GRES project, should make this possible.

Finally, the hydrochemical analysis showed that mainly bicarbonate and calcium concentrations are increasing when the surface water infiltrates below the surface.

6. Acknowledgments

The authors would like to thank the ORC staff, Pro£. L. Ramberg, Dr E. Veenendaal for their assistance in the field, the GS (Lobatse) Principal Hydrogeologist, Mr P. Phofuetsile for his kind permission to release staff and vehicle for the project, Mr S. Mukhopadyaya (GS) and Dr G. Sawula (UB) for the chemical analysis of water samples, Prof. F. Sefe (UB) for his permission to use Environmental Science Laboratory facilities, and finally Mrs F. Pula (Min. of Agriculture) for her assistance with soil sample analysis.

66

7. References

Aquifer Test, 1997: The Intuitive Aquifer Test Analysis Package, version 2.53, Waterloo Hydrologic Software, Canada.

Boonstra and De Ridder, 1981: Numerical Modelling of groundwater basins. ILRI, 29, Wageningen, The Netherlands, pp. 226.

Boulton, N.S., 1954: Unsteady radial flow to a pumped well allOwing for delayed yield from storage. Int. Ass. Sci. Hydro!., Rome, Pub!. 37, pp. 472-477.

Boulton, N.S., 1963: Analysis of data from non-equilibrium pumping tests allowing for delayed yield from storage. Proc. Inst. of Civil Engineers, Vo!. 26, pp. 469-482.

BRGM, 1984: Maun Groundwater Project, Report Department of Water Affairs, Gaborone.

Cronberg, G., A. Gieske, Martins, E., Prince Nengu, J. and Stenstrom, I-M., 1996: Major ion chemistry, plankton and bacterial assemblages of the Jao/Boro River, Okavango, Delta, Botswana: the swamps and flood plains, Arch. Hydrobio!./Supp!. ]07, Vo!. 3, pp. 335-407.

Dint;er, T., Heemstra, H.H. and Kraatz, D.B., 1976: The study of hydrological conditions in an experimental area in the seasonal swamp. Tech. Note No 20, UNDP /FAO, BOT /71/706.

Dint;er, T., Child, S. and Khupe, B., 1987: A simple mathematical model of a complex hydrological system - Okavango swamp, Botswana, J. Hydro!., Vo!. 93, pp. 41-65.

Fetter, C. W., 1988: (2nd edition.) Applied Hydrogeology, Macmillan Co, New York, U.sA, pp. 592.

Gabaake, G., Moehadu, M., Lehuma, J., Somolekae, B., Salas, G., Magowe, M., and Mabua, I., 1993: Data Report on Shashe Maun Pilot Borehole Construction Project. Department of Water Affairs, Gaborone.

Gieske, A., 1997: Modelling outflow from the Jao/Boro River system in the Okavango Delta, Botswana. J. Hydro!., Vo!. 193, pp. 214-239.

Gieske, A., 1998: Flow to a Well in a Water-Table Aquifer: Speeding up the Computation of Type Curves for Low Beta Values, Ground Water, (submitted).

Hutchins, D. G., Hutton, L. G., Hutton, S. M., Jones, C. R. and Loehnert, E. P., 1976: A summary of the geology, seismicity, geomorphology and hydrogeology of the Okavango Delta, Bulletin 7, Dept. Geo!. Surv., Lobatse, Botswana.

67

ILRI, 1974: Drainage principles and applications, Vo!. 3, Surveys and Investigations, Intern. Inst. for Land Reclamation and Improvements, Wageningen, The Netherlands, pp. 377.

Kruseman, G. P. and N. A de Ridder, 1990: Analysis and Evaluation Of Pumping Test Data, Second Edition (Completely Revised) ILRI publication 47. Intern. Inst. for Land Reclamation and Improvements, Wageningen, The Netherlands, pp. 377.

Marshall, T.J. and Holmes, J.W., 1988: Soil PhYSics, Cambridge University Press, New York, pp. 374.

McCarthy, T. S. and Ellery, W. N., 1994: The effect of vegetation on soil and groundwater chemistry and hydrology of islands in the seasonal swamps of the Okavango Fan, Botswana. J. Hydro!., Vo!. 154, pp. 169-193.

McCarthy, T. S. and Ellery, W. N., 1995: Sedimentation of the distal reaches of the Okavango Fan, Botswana, and its bearing on calcrete and silcrete (ganister) formation, J. Sedimentary Res., A65 (1), pp. 77-90.

MGWDP, 1997: Maun Groundwater Development Project, Final Report, Eastend Investments, Department of Water Affairs, Gaborone.

Moench, A F., 1993: Computation of Type Curves for Flow to Partially Penetrating Wells in Water-Table Aquifers, Ground Water, Vo!. 31 (6), pp. 966-971.

Moench, AF., 1994: Specific Yield as Determined by Type-Curve Analysis of Aquifer­Test Data. Ground Water, Vo!. 32 (6), pp. 949-957.

Moench, AF., 1995: Combining the Neuman and Boulton Models for Flow to a Well in an Unconfined Aquifer. Ground Water, Vo!. 33 (3), pp. 378-384.

Moench, A F., 1996: Flow to a Well in a Water-Table Aquifer: An Improved Laplace Transform Solution. Groundwater, Vo!. 34 (4), pp. 593-596.

Moench, A F., 1997: Flow to a well of finite diameter in a homogeneous, anisotropic water table aquifer, Water Resources Research, Vo!. 33 (6), pp. 1397-1407.

Neuman, S.P. 1972: Theory of Flow in Unconfined Aquifers considering Delayed Response of the Water Table. Water Resour. Res., Vo!. 8, pp. 1031-1044.

Neuman, S.P. 1974: Effects of partial penetration on flow in unconfined aquifers considering delayed aquifer response. Water Resour. Res., Vo!. 10, pp. 303-312.

Nwankor, G.!., GiIlham, R.W., Van del' Kamp, G. and Akindunni, F.F., 1992: Unsaturated and Saturated flow in response to pumping of.an unconfined aquifer: Field evidence of delayed drainage. Ground Water, Vo!. 30, pp. 690-700.

68

I

Ringrose, S., Vanderpost, C., Matheson, W. and Webster, H., 1998: Assessment of ecological units in the Okavango Delta, using remotely sensed data - with particular reference to the SPOT vegetation sensor (in press).

Sawula, G., Martins, E., Nengu, J. and Themner, K., 1992: Notes on Trace Metals in the Boro River, Okavango Delta, Botswana Notes and Records, Vol. 24, pp. 135-149.

Scudder, T., Manley, R. E., Coley, R. W., Davis, R. K., Green, J., Howard, G. W., Lawry, S. W., Martz, D., Rogers, P. P., Taylor, A. R. D., Turner, S. D., White, G. F. and Wright, E. P., 1993: The IUCN (World Conservation Union) Review of the Southern Okavango Integrated Water Development Project. IUCN, Switzerland, pp. 543.

SMEC, Snowy Mountains Engineering Corporation, 1987: Southern Okavango Integrated Water Development Project, Phase I, Final Report, 5 Vols., Department of Water Affairs, Gaborone.

Zangar, C.N., 1953: Theory and problems of water percolation. US. Bureau of Reclamation. Engineering Monograph No. 8. Denver, Col., pp. 76.

69

PZ2 FLOOD PLAIN (Fig. 7 ) -0.252 Toe

date time level LEVEL date (hrs) (m) (m)

25-APR-97 1200 2.70 -2.95 25.50 18-JUN-97 1200 3.02 -3.27 79.50 dry 20-JUN-97 1200 3.02 -3.27 81.50 dry 22-JUN-97 1200 3.02 -3.27 83.50 dry 24-JUN-97 1200 3.02 -3.27 85.50 dry 26-JUN-97 1200 2.95 -3.20 87.50 28-JUN-97 856 2.89 -3.14 89.36 29-JUN-97 914 2.80 -3.05 90.38 30-JUN-97 842 1.40 -1. 65 91. 35 01-JUL-97 827 0.22 -0.47 92.34 02-JUL-97 1200 FLOODED -0.32 93.50 03-JUL-97 1200 'FLOODED -0.30 94.50 04-JUL-97 1200 FLOODED -0.28 95.50 05-JUL-97 1200 FLOODED -0.26 96.50 06-JUL-97 1200 FLOODED -0.24 97.50 07-JUL-97 1200 FLOODED -0.22 98.50 08-JUL-97 1200 FLOODED -0.20 99.50

PZ4 FLOOD PLAIN (Fig. 8) 0.796 Toe

date time level LEVEL date (hrs) (m) (m)

25-APR-97 1200 4.06 -3.26 25.50 18-JUN-97 1200 4.60 -3.80 79.50 20-JUN-97 1200 4.48 -3.68 81.50 22-JUN-97 1200 4.20 -3.40 83.50 24-JUN-97 1200 3.84 -3.04 85.50 26-JUN-97 1200 3.47 -2.67 87.50 29-JUN-97 939 3.17 -2.37 90.39 30-JUN-97 850 3.06 -2.26 91. 35 02-JUL-97 900 2.87 -2.07 93.38 03-JUL-97 1000 2.81 -2.01 94.42 04-JUL-97 907 2.74 -1.94 95.38 05-JUL-97 920 2.67 -1.87 96.38 07-JUL-97 1037 2.65 -1.85 98.43 08-JUL-97 906 2.52 -1. 72 99.38

piezA floodp1 (Fig. 9) -0.257 Toe Toe reduced

date time level level (hrs) (m) (m)

28-JUN-97 1601 2.970 -3.227 89.667 29-JUN-97 900 2.910 -3.167 90.375 30-JUN-97 840 1. 570 -1.827 91.350 01-JUL-97 827 0.400 -0.657 92.345 02-JUL-97 800 fld -0.397 93.333 03-JUL-97 600 fld -0.347 94.333 04-JUL-97 800 fld -0.297 95.333 05-JUL-97 800 fld -0.247 96.333 07-JUL-97 800 fld -0.196 98.333

3

piezB floodpl (Fig. 10 ) -0.249 Toe Toe reduced

date time level level (hrs) (m) (m)

29-JUN-97 900 2.850 -3.099 90.38 30-JUN-97 840 1.580 -1. 829 91. 35 01-JUL-97 827 0.400 -0.649 92.34 02-JUL-97 800 fld -0.397 93.33 03-JUL-97 800 fld -0.347 94.33 04-JUL-97 800 fld -0.297 95.33 05-JUL-97 800 fld -0.247 96.33 07-JUL-97 800 fld -0.196 98.33

pieze weir (Fig. 11) 0.505 TOe Toe reduced

date time level level (hrs) (m) (m)

30-JUN-97 1209 1.165 -0.660 91. 504 01-JUL-97 851 1.100 -0.595 92.355 02-JUL-97 952 1.030 -0.525 93.397 03-JUL-97 930 0.995 -0.490 94.388 04-JUL-97 835 0.970 -0.465 95.348 05-JUL-97 845 0.950 -0.445 96.352 07-JUL-97 820 0.913 -0.408 98.342 08-JUL-97 840 0.900 -0.395 99.350

piezD weir (Fig. 11) 0.512 Toe Toe reduced

date time level level (hrs) (m) (m)

01-JUL-97 1355 1.120 -0.608 92.565 02-JUL-97 1000 1. 035 -0.523 93.417 03-JUL-97 930 1.005 -0.493 94.388 04-JUL-97 834 0.971 -0.459 95.347 05-JUL-97 845 0.945 -0.433 96.352 07-JUL-97 820 0.920 -0.408 98.342 08-JUL-97 840 0.905 -0.393 99.350

piezE weir (Fig. 11) 0.524 Toe Toe reduced

date time level level (hrs) (m) (m)

01-JUL-97 1355 1.130 -0.606 92.565 02-JUL-97 1000 1.055 -0.531 93.417 03-JUL-97 930 1.015 -0.491 94.388 04-JUL-97 840 0.985 -0.461 95.350 05-JUL-97 846 0.962 -0.438 96.353 07-JUL-97 822 0.935 -0.411 98.343 08-JUL-97 840 0.915 -0.391 99.350

piezF road/pan (Fig. 12 ) -0.520 Toe Toe reduced

date time level level (hrs) (m) (m)

04-JUL-97 1403 4.070 -4.590 95.585 05-JUL-97 930 4.079 -4.599 96.388 07-JUL-97 1025 4.082 -4.602 98.427 08-JUL-97 918 4.085 -4.605 99.382

4

piezG road/pan (Fig. 13) 0.050 TOe Toe reduced

date time level level (hrs) (m) (m)

05-JUL-97 1200 3.550 -3.500 96.500 07-JUL-97 1029 3.520 -3.470 98.429 08-JUL-97 912 3.480 -3.430 99.380

piezI ORetree (Fig. 14) ND TOe Toe reduced

date time level level (hrs) (m) (m)

06-JUL-97 810 5.140 -5.140 97.338 07-JUL-97 ~10 4.640 -4.640 98.338 08-JUL-97 831 4.630 -4.630 99.346

piezJ floodp1 (Fig. 15) 0.189 Toe Toe reduced

date time level level (hrs) (m) (m)

06-JUL-97 1200 1.310 -1.121 97.500 07-JUL-97 845 1. 250 -1. 061 98.352 08-JUL-97 856 1.170 -0.981 99.357

piezK floodpl (Fig. 15) 0.166 Toe Toe reduced

date time level level (hrs) (m) (m)

06-JUL-97 1400 1.260 -1. 094 97.583 07-JUL-97 850 1.202 -1.036 98.354 08-JUL-97 900 1.125 -0.959 99.375

5

~ ~O E E '-'L­eo o e ~(j) 0.0 > 0 m e m,-,

0.40 ,----------------------------------------

0.30

0.20

0.10

0.00 5

Boro River level near Camp Site

10 15 20

June 1997

25 30 5 10

July 1997

Fig. 1 Recorded rise of water level in Boro River near Camp Site.

-0.16

r-.. -0,18

5 § -0.20

:;::: o > ·m m

-0.22

-0.24

weir level relative to benchmark

- 0 .26 ±--------:::c--------=---------,--------20 25 .30 5 10

June 1997 July 1997

Fig. 2 Recorded increase in water level at the weir.

-0.16 "'---------------------------------~

-0.17 Floodplain main channel staff gauge on transect 1

'"' E -0.18

'-' e 0 -0.19

:;::: 0 > m

-0.20

m -0.21

-0.22

-0.23 85 90 95 100

24-JUN-97 09-JUL-97

Fig. 3 Recorded increase in water level main channel through flood plain.

Appendix C

6

-0.60 T------------------~;(l

~

U -0.80 ~O ,sG Qi Ole -1.00 ~'ii5 -0 ~O 2_ 00 -1.20

3D. -gt2 § g -1.40 Ol-I=

piezometer Camp Site close to Boro River

- , . 60 :3::-~--:c::--__::c:---=c_-_:_:r_=_~=::_~,_r::_-:_J 20 40 60 BD 100 120 140 160

20-FEB-97 1O-JUL-97

Fig. 4 Hydrograph of piezometer near Camp Site.

-2.00 T---------------------,

-2.20

-2.40

-2.60

-2.80

-3.00

-..3.20

piezometer ObseNation Island close to Boro River

•

-..3.40 2;;10;:::-----:-4':::O-----::c6':::o-----::cs '='o----,--ioo

20-APR-97 09-JUL-97

Fig. 5 Hydrograph of piezometer on Observation Island.

Appendix C

7

-2.60 ...---------------------;:

-2.80

-3.00

-3.20

-3.40

-3.60

-3.80

piezometer 1 forest edge on transect 1

-4.00 2-'10--~--4'0--~--6:;-0::-----8='0::--~--;-:!, 00

20-APR-97 09-JUL-97

Fig. 6 Hydrograph of piezometer 1 on transect 1 (flood plain).

.-..-l': EO ~E -.s:; Q)o ii;c -Q) ~.o

~E 3-0

-OQ) CO :J:J 0-0 ~Q) O>~

0.00 :r-----------------.,.----:J piezometer 2 flood plain

-1.00 " on transect 1

-2.00 -:

-3.00,

-4.00

-5.002~0-----4~0::--~-~60::----~80~---~,~00

20-APR-97 09-JUL-97

Fig. 7 Hydrograph of piezometer 2 on transect 1 (flood plain). -1.50 "'-----______________ ,

-2.00

-2.50

-3.00

-3.50

-4.00

piezometer 4 road on transect 1

-4.50 4--_-_-,.--___ -.,...--_-_,.__--_--.j 20 40 60 80 100

20-APR-97 09-JUL-97

Fig. 8 Hydrograph of piezometer 4 on transect 1 (floodplain). Note: transect 1 is shown in Fig. 16.

Appendix C

8

0.00

~-l! piezometer A EO -1.00

on transect 1 ~E Qj{j >c ~<1> -2,00 ~.Q

$'0 O+-3"0

"0<1> -3.00 cO ::J::J 0"0 ~<1> Ol~ -4.00 '

-5.00 20 40 60 80 100

20-APR-97 09-JUL-97

Fig. 9 Hydrograph of piezometer A on transect 1 (floodpJain).

0.00

"" piezometer B

EO -1.00 on transect 1 ~E -.c <1>0 >c ~<1> -2.00 ~.Q

$'0 O+-3"0

"0<1> cO

-3.00 .::

::J::J 0"0 ~<1> Ol~ -4.00

-5.00 20 40 60 80 100

20-APR-97 09-JUL-97

Fig. 10 Hydrograph of piezometer B on transect 1 (floodpJain).

Appendix C

9

-0.35 ~--------------------------------------,

-0.40

-0.45

-0.50

-0.5!!>

-0.60

-0.65

piezometers C,D and E near the weir

• C o Dand E

-0.75 90 91 92 93 94 95 96 97 98 99 100

29-JUN-97 09-JUL-97

Fig, 11 Hydrographs of piezometers C, D and E near the weir,

-4.58,---------------------------------------,

-4.59

-4.61

piezometer F near the road on pan inlet channel

- 4.62 :f:---",---=--=--::r---;:>5;;---9Z-6 --;:>gC::7 --;:;9;;;8--;;'9;;;9~';-;!OO 90 91 92 93 94 9

29-JUN-97 09-JUL-97

Fig, 12 Hydrograph of piezometer F next to the road in the main pan inlet channel.

-3.42 ~--------------------------------------,

piezometer G -3.44 on pan inlet channel

-3-46

-3-48

-3.50

-3.52 90 91 92 93 94 95 96 97 98 99 100

29-JUN-97 09-JUL-97

Fig. 13 Hydrograph of piezometer G on the edge of the pan inlet channel.

Appendix C

10

-4.60 ~------------------------------------~

-4.70

-4.BO

-4.90

-5.00

-5.10 '

-5.20

piezometer I near ORC tree on Half Moon Island

-5.30 4---,---,---,---,---~--~--~--,---,-~ 90 91 92 93 94 95 96 97 98 99 100

29-JUN-97 09-JUL-97

Fig. 14 Hydrograph of piezometer I near ORC tree on Half Moon Island. The increase in level is due to water level recovery after drilling. Conductivity is low.

-0.95 ~--------------------------------------,

-1.00

-1.05

-1.10

-1.15

piezometers J and K close to track/flood plain

-1.20 ~--~--,---~--~--,---,---~--~--~~~ 90 91 92 93 94 95 96 97 98 99 100

29-JUN-97 09-JUL-97

Fig. 15 Hydrographs of piezometers J and K on the flood plain.

Appendix C

11

piez4 1.0 plez.l

0.0 piez2

~

E -1.0 ......, C 0

:;:::: -2.0

~ (j) (jj -3.0

April 27, 19 July 8,1

-4_0

-5.0 -100 o 100 200 300

distance along flood plain transect 1 Cm)

Fig, 16 Transect 1 on the 'floodplain showing water levels on April 27, 1997 and July 8, 1997,

benchmark 0

-1

-2

ridge with riparian forest

······ .. piei.ometefF····

main pan

piezometer G main channel

Fig, 17 Cross-section from weir (main channel) across the pan,

Appendix C

12

APPENDIX D WELL TEST DATA

Appendix D

Contents

1. Well Test Measurements

2.

3.

Bail Test Piezometer Camp Site Recovery Test Observation Piezometer B Recovery Test Observation Hole A Constant Rate Test and Recovery Test Observation Hole E (test 1) Constant Rate and Recovery Test Hole D (Test 1) Constant Rate and Recovery Test Hole D (Test 2) Constant Rate and Recovery Test Hole E (Test 2) Constant Rate Tests Holes F and G Constant Rate and Recovery Test Hole K

Raw data plots

Fig. 1 Raw data plot constant rate test Bl Fig. 2 Plot of recovery test data Bl. Note that for late times

the water level was rising due to flooding of the area. Fig. 3 Plot of raw drawdown data constant rate test Dl Fig. 4 Plot of raw recovery data Dl. Fig. 5 Plot of Raw Data Constant Rate Test El Fig. 6 Raw data recovery test El. Fig. 7 Raw data plot of constant rate test D2. Fig. 8 Raw data plot of recovery test D2. Fig. 9 Raw data plot of constant rate test E2. Fig. 10 Raw data plot of recovery test E2. Fig. 11 Raw data plot of recovery test G 1 Fig. 12 Raw data plot of constant rate test Kl. Fig. 13 Raw data plot of recovery test Kl.

Moench interpretation data

a. Site AB

Fig. 14 Data on piezometer configuration of site AB. Fig. 15 Well test Bl, constant rate. Fig. 15b Drawdown data well test B1, constant rate. Fig. 16 Drawdown plot for recovery test Bl. Fig. 16b Drawdown data for recovery test Bl. Fig. 17 Drawdown plot for recovery test B1

(reduced number of points). Fig. 17b Drawdown data for recovery test B1

(reduced number of points).

Appendix D

(i)

page

1 2 3

4 5 6 7 8 9

10

10 11 11 12 12 13 13 14 14 15 16 16

17 18 19 20 21

22

23

b. Site CDE (test 1)

Fig. 18 Data on piezometer configuration CDE (test 1). 24 Fig. 19 Drawdown plot for constant rate test Dl. 25 Fig. 19b Drawdown data for constant rate test D1. 26 Fig. 20 Drawdown plot for recovery test D1. 27 Fig. 20b Drawdown data for recovery test Dl. 28 Fig. 21 Drawdown plot for constant rate test El 29 Fig. 21b Drawdowri data for constant rate test El. 30 Fig. 22 Drawdown plot for recovery test El. 31 Fig. 22b Drawdown data for recovery test El. 32 Fig. 23 Composite drawdown plot for constant rate test

Dl,El. 33 Fig.23b Drawdown data for composite test Dl. 34 Fig. 23c Drawdown data for composite test El. 35

c. Site CDE (test 2)

Fig. 24 Data on piezometer configuration CDE (test2). 36 Fig. 25 Drawdown plot of constant rate test D2 (y= lxl09). 37 Fig. 25b Drawdown data of constant rate test D2 (y= lxl09

). 38 Fig. 26 Drawdown plot of constant rate test D2 (y=3). 39 Fig. 26b Drawdown data of constant rate test D2 (y=3). 40 Fig. 27 Drawdown plot of recovery test D2. 41 Fig. 27b Drawdown data of recovery test D2. 42 Fig. 28 Drawdown plot of constant rate test E2 (y= lxl09

). 43 Fig. 28b Drawdown data of constant rate test E2 (y= lxl09

). 44 Fig. 29 Drawdown plot of constant rate test E2 (y=3). 45 Fig. 29b Drawdown plot of constant rate test E2 (y=3). 46 Fig. 30 Drawdownplot of recovery test E2. 47 Fig. 30b Drawdown data of recovery test E2. 48 Fig. 31 Drawdown plot of composite constant rate test CDE2

(y= lxl09) (drawdown data are the same as for Fig. 32). 49

Fig. 32 Drawdown plot for composite test CDE2 (y= 3). Note that parameters band L for piezometer E have been changed slightly (see discussion main text). 50

Fig.32b Drawdown data piezometer E composite plot CDE2. 51 Fig. 32c Drawdown data piezometer D composite plot CDE2. 52

d. Site G

Fig. 33 Data for piezometer G. 53 Fig. 34 Drawdown plot for recovery test Gl. 54 Fig. 34b Drawdown data for recovery test G 1. 55

Appendix D

(ii)

e. Site JK

Fig. 35 Data for the analysis of piezometers J and K. Fig. 36 Drawdown plot for constant rate test Kl. Fig. 36b Drawdown data for constant rate test Kl. Fig. 37 Drawdown plot for recovery test Kl. Fig. 37b Drawdown data for recovery test Kl.

4. Zangar method

Fig. 38 Diagram showing basic parameters of the Zangar method

56 57 58 59 60

(Drainage Principles and Applications, ILRI, Vol HI, 1974). 61 Fig. 39 Zangar parameters as applied here. hiD is the difference between

the pump intake and the bottom of the hole, whereas hhi = hiD + a. Length a is half the distance from the pump intake to the initial groundwater table. 61

Zangar method input data 62

Program to use Zangar method 63

Appendix D

(iii)

1. Well Test Measurements

Bail Test Piezometer Camp Site

SLc!!!Q01 27-APR-97 1.22 hz PZcamp time time tz h hz

hr min s (min) 9 14 15 554.25 0.00 1.650 0.430 9 15 0 555.00 0.75 1.610 0.390 9 16 0 556.00 1.75 1.610 0.390 9 17 0 557.00 2.75 1.606 0.386 9 20 0 560.00 5.75 1.600 0.380 9 25 0 565.00 10.75 1.580 0.360 9 30 0 570.00 15.75 1.570 0.350

15 7 0 907.00 352.75 1.280 0.060

Appendix D

1

Recovery Test Observation Piezometer B

CRQzB1 Recover~ ObsHote B 29~Jun~97

(r=0.38m) Pumped Hole A rest\.JL 2.90 11.32hrs

Hole B restWl 2.85 09.00hrs Pumpintake 4.00 Toe p~time 65 minutes

Pumprate time volume Freq rate (s) Cl tr) (Hz) (m3/d) 95 27.5 182 25.01 97 27.5 182 24.49 24.75 avg

eRT time level drawd

(min) (m) (m)

1 2.960 0.160 2 2.965 0.165 3 2.970 0.170 4 2.985 0.185 5 2.990 0.190 6 2.990 0.190

10 2.995 0.195 15 2.996 0.196 30 2.997 0.197 45 2.997 0.197 60 2.997 0.197 65 2.997 0.197

recovery t' t tit! s

0.5 2.880 65.5 131.00 0.13 1.0 2.880 66.0 66.00 0.13 1 .5 2.870 66.5 44.33 0.12 2.0 2.865 67.0 33.50 0.12 2.5 2.860 67.5 27.00 0.11 3.0 2.855 68.0 22.67 0.10 3.5 2.855 68.5 19.57 0.10 4.0 2.853 69.0 17.25 0.10 4.5 2.851 69.5 15.44 0.10 5.5 2.847 70.5 12.82 0.10 7.5 2.840 72.5 9.67 0.09

11.5 2.835 76.5 6.65 0.08 15.5 2.830 80.5 5.19 0.08 20.5 2.820 85.5 4.17 0.07 24.5 2.820 89.5 3.65 0.07 30.5 2.811 95.5 3.13 0.06 36.5 2.809 101.5 2.78 0.06 42.5 2.802 107.5 2.53 0.05 48.5 2.800 113.5 2.34 0.05 54.5 2.790 119.5 2.19 0.04 60.5 2.790 125.5 2.07 0.04 70.5 2.780 135.5 1.92 0.03 80.5 2.770 145.5 1.81 0.02 90.5 2.770 155.5 1.72 0.02

Appendix D

2

Recovery Test Observation Hole A

recover:i A treat as bai l test rest Wlevel 2.90 morning test????

time leveL (min) (rn)

0.83 2.940 0.0400 1.000 1.50 2.930 0.0300 0.750 2.00 2.925 0.0250 0.625 3.00 2.922 0.0220 0.550 5.00 2.917 0.0170 0.425 6.00 2.912 0.0120 0.300 8.00 2.910 0.0100 0.250

date time A B 29'JUN-97 900 2.85

918 2.91 1132 2.90 1500 2.77

30-JUN-97 840 1.57 1. 58 7.06 cm/hrt

Appendix D

3

Constant Rate Test and Recovery Test Observation Hole E (test 1)

eRpzE1

PmpRate

time (min) 15.5 30.5 45.5

50 54 64 79

eRT

time (m;n)

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 7.0

10.0 15.0 20.0 25.0 30.0 45.0 60.0 75.0 90.0

recovery time t I

(min) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 7.0

10.0 15.0 20.0 25.0 30.0 45.0 60.0 75.0

Appendix D

ObsHole E (r·0.225m) PmpHoLe e PmpTime

01·JUL·97 restWL

PmpIntake 99 minutes

freq 127/128Hz start end hr min s hr 14 12 4 14 14 22 11 14 14 28 0 14 14 44 0 14 14 48 0 14 15 0 30 15 15 15 33 15

hole E

TOeWL dd (m) (m)

1.130 0.040 1.190 0.100 1.220 0.130 1.245 0.155 1.265 0.175 1.270 0.180 1.285 0.195 1.290 0.200 1.305 0.215 1.330 0.240 1.345 0.255 1.375 0.285 1.375 0.285 1.380 0.290 1.385 0.295 1.398 0.308 1.405 0.315 1.402 0.312 1 .410 0.320

TOeWL dd time t (m) (m) (m;n)

1.350 0.260 99.5 1.280 0.190 100.0 1.240 0.150 100.5 1.220 0.130 101.0 1.210 0.120 101 .5 1.207 0.117 102.0 1.200 0.110 102.5 1.198 0.108 103.0 1.194 0.104 104.0 1.185 0.095 106.0 1.173 0.083 109.0 1.160 0.070 114.0 1.150 0.060 119.0 1 .140 0.050 124.0 1.135 0.045 129.0 1.120 0.030 144.0 1. 115 0.025 159.0 1.105 0.015 174.0

4

1.09 Toe 2.10 TOe

start 1355hrs

volume 27.5Ltr

min s 14 29 24 37 30 23 46 26 50 28 3 0

18 6

t/t'

199.00 100.00 67.00 50.50 40.60 34.00 29.29 25.75 20.80 15.14 10.90 7.60 5.95 4.96 4.30 3.20 2.65 2.32

time rate s (m3/d)

145 16.39 146 16.27 143 16.62 146 16.27 148 16.05 150 15.84 153 15.53

avg16.14

Constant Rate and Recovery Test Hole D (Test 1)

CrRzD1 ObsHole 0 01-JU"'97 (r=0.470m) restWl 1. 08 TOC PmpHole C Pmplntake 2.10 TOC PmpTime 99 minutes start 1355hrs

PmpRate freq 127/128Hz volume 27.51tr

time start end time rate (min) hr min s hr min s s (m3/d) 15.5 14 12 4 14 14 29 145 16.39 30.5 14 22 11 14 24 37 146 16.27 45.5 14 28 0 14 30 23 143 16.62

50 14 44 0 14 46 26 146 16.27 54 14 48 0 14 50 28 148 16.05 64 15 0 30 15 3 0 150 15.84 79 15 15 33 15 18 6 153 15.53

16.14 CRT hole 0

time TOCWl dd (min) (m) (m) 0.75 1 .120 0.040 1.25 1 .150 0.070 1.75 1.180 0.100 2.25 1.195 0.115 2.75 1.205 0.125 3.25 1.220 0.140 3.75 1.225 0.145 4.25 1.240 0.160 4.75 1.240 0.160 5.50 1.250 0.170 7.50 1.265 0.185

10.50 1.280 0.200 15.50 1.295 0.215 20.50 1.305 0.225 25.50 1.318 0.238 30.50 1.320 0.240 45.50 1.332 0.252 60.50 1.340 0.260 75.50 1.345 0.265 90.50 1.343 0.263

recovery time t I TOCWl dd time t t/t '

(min) (m) (m) (min) 0.75 1.270 0.180 99.8 133.00 1.25 1.240 0.150 100.2 80.20 1.75 1 .210 0.120 100.8 57.57 2.25 1.200 0.110 101.2 45.00 2.75 1.195 0.105 101.8 37.00 3.25 1.190 0.100 102.2 31.46 3.50 1.185 0.095 102.5 29.29 4.25 1.182 0.092 103.2 24.29 5.25 1.173 0.083 104.2 19.86 7.25 1.163 0.073 106.2 14.66

10.25 1.155 0.065 109.2 10.66 15.25 1.140 0.050 114.2 7.49 20.12 1.130 0.040 119.1 5.92 25.25 1 .125 0.035 124.2 4.92 30.25 1.120 0.030 129.2 4.27 45.25 1.109 0.019 144.2 3.19 60.25 1.096 0.006 159.2 2.64 75.25 1.092 0.002 174.2 2.32

Appendix D

5

A S

Constant Rate and Recovery Test Hole D (Test 2)

CRezD2 ObsHole 0 02-JUL-97 (r=0.470m) restWL 1.035 Toe PfIllHole e Pmplntake 2.85 Toe PmpTime 300 minutes start 1017hrs

Pf11'Rate freq 131Hz volume 27.5ltr

time start end time rate (min) hr min s hr min s s (m3/d)

11 10 28 10 10 30 37 147 16.16 16 10 33 10 10 35 35 145 16.39 25 10 42 52 10 45 22 150 15.84 31 10 48 10 10 50 35 145 16.39 62 11 19 30 11 22 0 150 15.84 91 11 48 30 11 51 0 150 15.84

139 12 36 0 12 38 30 150 15.84 142 12 39 40 12 42 10 150 15.84 158 12 55 40 12 58 5 145 16.39 175 13 12 10 13 14 36 146 16.27 208 13 45 50 13 48 19 149 15.95 219 13 56 50 13 59 19 149 15.95 241 14 18 30 14 20 58 148 16.05 294 15 11 25 15 13 51 146 16.27

16.07

eRT hole 0

time ToeWL dd (min) (m) (m) 0.75 1.100 0.065 1.50 1.130 0.095 1.80 1.150 0.115 2.25 1.165 0.130 2.75 1.180 0.145 3.25 1.185 0.150 3.75 1.190 0.155 4.25 1.200 0.165 5.25 1.210 0.175 7.25 1.228 0.193

10.25 1.240 0.205 15.25 1.260 0.225 20.25 1.270 0.235 25.25 1.280 0.245 recovery 30.25 1.283 0.248 time t l TOeWL dd time t t/t '

45.25 1.302 0.267 (min) (m) (m) (min)

60.25 1.311 0.276 0.75 1.260 0.225 300.8 401.00

75.25 1.320 0.285 1.25 1.230 0.195 301.2 241.00

90.25 1.326 0.291 1. 75 1.203 0.168 301.8 172.43

120.25 1.333 0.298 2.25 1.190 0.155 302.2 134.33

180.25 1.341 0.306 2.75 1.185 0.150 302.8 110.09

240.25 1.343 0.308 3.25 1.180 0.145 303.2 93.31

300.25 1.343 0.308 3.75 1. 175 0.140 303.8 81.00 4.25 1.170 0.135 304.2 71.59 5.25 1.160 0.125 305.2 58.14 7.25 1.148 0.113 307.2 42.38

10.25 1.135 0.100 310.2 30.27 15.25 1.120 0.085 315.2 20.67 20.25 1. 108 0.073 320.2 15.81 25.25 1.100 0.065 325.2 12.88 30.25 1.092 0.057 330.2 10.92 45.25 1.075 0.040 345.2 7.63 60.25 1.068 0.033 360.2 5.98 75.25 1.059 0.024 375.2 4.99 90.25 1.052 0.017 390.2 4.32

Appendix D

6

j

Constant Rate and Recovery Test Hole E (Test 2)

CRezE2 ObsHote E 02· JUl·97 (r=0.225m) restWl 1.052 Toe PfllJHole e Pmplntake 2.85 Toe PmpTime 300 minutes start 1017hrs

PmpRate freq 131Hz volume 27.5ltr

time start end time rate (min) hr min s hr min s s (m3/d)

11 10 28 10 10 30 37 147 16.16 16 10 33 10 10 35 35 145 16.39 25 10 42 52 10 45 22 150 15.84 31 10 48 10 10 50 35 145 16.39 62 11 19 30 11 22 0 150 15.84 91 11 48 30 11 51 0 150 15.84

139 12 36 0 12 38 30 150 15.84 142 12 39 40 12 42 10 150 15.84 158 12 55 40 12 58 5 145 16.39 175 13 12 10 13 14 36 146 16.27 208 13 45 50 13 48 19 149 15.95 219 13 56 50 13 59 19 149 15.95 241 14 18 30 14 20 58 148 16.05 294 15 11 25 15 13 51 146 16.27

16.07

eRT hole E

time ToeWl dd (min) (m) (m) 0.50 1 .105 0.053 1 . 17 1.160 0.108 1.67 1.200 0.148 2.00 1 .215 0.163 2.50 1.230 0.178 3.00 1.245 0.193 3.50 1.255 0.203 4.00 1.255 0.203 5.00 1.280 0.228 7.00 1.295 0.243

10.00 1.310 0.258 15.00 1.325 0.273 20.00 1.340 0.288 25.00 1.350 0.298 30.00 1.355 0.303 recovery 45.00 1.372 0.320 time t' ToeWl dd time t tit' 60.00 1.387 0.335 (min) (m) (m) (min) 75.00 1.392 0.340 0.50 1.340 0.288 300.5 601.00 90.00 1.398 0.346 1.00 1.280 0.228 301.0 301.00 120.75 1.406 0.354 1.50 1.235 0.183 301.5 201.00 180.00 1.412 0.360 2.00 1.212 0.160 302.0 151.00 240.00 1.414 0.362 2.50 1.205 0.153 302.5 121.00 300.00 1.413 0.361 3.00 1.198 0.146 303.0 101.00

3.50 1.195 0.143 303.5 86.71 4.00 1.188 0.136 304.0 76.00 5.00 1.182 0.130 305.0 61.00 7.00 1.170 0.118 307.0 43.86

10.00 1. 153 0.101 310.0 31.00 15.00 1. 140 0.088 315.0 21.00 20.00 1.125 0.073 320.0 16.00 25.00 1.120 0.068 325.0 13.00 30.00 1.105 0.053 330.0 11.00 45.00 1.090 0.038 345.0 7.67 60.00 1.080 0.028 360.0 6.00 75.00 1.070 0.018 375.0 5.00 90.00 1.063 0.011 390.0 4.33

Appendix D 7

Constant Rate Tests Holes F and G

CR(;!ZF1 04-JUL-97 rest'WL 4.070 Toe

Pmplntake 4.95 Toe PmpTime 117 minutes start 1423hrs

PmpRate freq 93Hz volume 27.5ltr

time start end time rate (min) hr min s hr min s s (m3/d)

15 26 8 15 34 3 475 5.00

CrQzG1 G 04-JUL-97 restWL 3.530 TOe

Pmptntake 4.53 Toe PmpTime 184 minutes start 1150hrs

PmpRate freq 108Hz volume 27.5ltr

time start end time rate (min) hr min s hr min s s (m3/d)

14 12 14 30 12 18 50 260 9.14 37 12 37 25 12 41 55 270 8.80 49 12 49 0 12 53 32 272 8.74 70 13 10 0 13 14 35 275 8.64 97 13 37 0 13 41 41 281 8.46

168 14 48 0 14 52 47 287 8.28

8.67 recovery

time tl lOeWL time t drawd tit' (min) (m) (min) (m)

1.0 3.61 185.0 0.080 185.00 1 .5 3.61 185.5 0.080 123.67 2.0 3.61 186.0 0.080 93.00 2.5 3.61 186.5 0.080 74.60 3.0 3.61 187.0 0.080 62.33 3.5 3.6 187.5 0.070 53.57 4.0 3.592 188.0 0.062 47.00 5.0 3.59 189.0 0.060 37.80 7.0 3.585 191.0 0.055 27.29

11.0 3.579 195.0 0.049 17.73 15.0 3.575 199.0 0.045 13.27 20.0 3.569 204.0 0.039 10.20 25.0 3.565 209.0 0.035 8.36 30.0 3.562 214.0 0.032 7.13 45.0 3.555 229.0 0.025 5.09 60.0 3.549 244.0 0.019 4.07 75.0 3.546 259.0 0.016 3.45 90.0 3.546 274.0 0.016 3.04

Appendix D

8

Constant Rate and Recovery Test Hole K

eR~zK1 ObsHoLe K 07-JUL-97 (ro O.57rn) restlolL 1.200 Toe PmpHole J Pmplntake 3.03 Toe PmpTime 135 minutes start 0915hrs

PmpRate freq 175Hz voLume 27.51tr

time start end time rate (min) hr min s hr min s s (m3/d)

0 9 15 40 9 17 33 113 21.03 11 9 26 40 9 28 31 111 21.41 22 9 37 10 9 39 6 116 20.48

avg 20.97 freq reset 150Hz

28 9 43 40 9 45 48 128 18.56 40 9 55 5 9 57 13 128 18.56 56 10 11 0 10 13 8 128 18.56

124 11 19 39 11 21 55 136 17.47 .vg 18.29

eRT hoLeK

time TOe~L dd (min) (rn) (rn) 0.50 1.270 0.070 1.00 1.330 0.130 1.50 1.360 0.160 2.00 1.370 0.170 2.50 1.380 0.180 3.00 1.386 0.186 3.50 1.393 0.193 4.00 1.398 0.198 5.00 1.405 0.205 7.00 1.410 0.210

10.00 1.421 0.221 15.00 1.426 0.226 20.00 1.431 0.231 25.00 1.432 0.232 30.00 1.430 0.230 45.00 1.435 0.235 60.00 1.440 0.240 90.00 1.435 0.235

121.75 1.432 0.232 135.00 1.426 0.226

recovery time tl TOe~L dd time t tIt I

(min) (rn) (rn) (min) 0.50 1.373 0.203 135.5 271.00 1.00 1.320 0.150 136.0 136.00 1.50 1.285 0.115 136.5 91.00 2.00 1.27'3 0.103 137.0 68.50 2.50 1.270 0.100 137.5 55.00 3.00 1.268 0.098 138.0 46.00 3.50 1.265 0.095 138.5 39.57 4.00 1.262 0.092 139.0 34.75 5.50 1.256 0.086 140.5 25.55 7.00 1.250 0.080 142.0 20.29

10.50 1.245 0.075 145.5 13.86 15.00 1.230 0.060 150.0 10.00 20.00 1.228 0.058 155.0 7.75 26.00 1.222 0.052 161.0 6.19 30.75 1 .215 0.045 165.8 5.39 45.00 1.202 0.032 180.0 4.00 60.00 1.195 0.025 195.0 3.25 90.00 1.186 0.016 225.0 2.50

Appendix D

9

"" S '-../

~ 0

~ ,.. "0

r-.

S '-../

~ 0

"0 ~ ro ,..

"0

Constant Rote Test 81 29-JUN-1997

0.20 0 0

0.18

0.16

0.14

0.12

0.10

0.08

0.06

0.04

0.02

0.00 10-1 10

time (min)

Fig. 1 Raw data plot constant rate test B 1

0.14

0.12

0.10

0.08

0.06

0.04

0.02

Recovery Test B1 29-JUN-1997

J'

0.00 10-1

0

0

10

tit'

0

0

0

0

10 ,

10 '

Fig. 2 Plot of Recovery test data Bl. Note that for late times the water level was rising due to flooding of the area.

Appendix D

10

0.30

0.25

~

El 0.20

'--'

~ 0.15

] ... '0 0.10

0.05

0.00

Constant Rate Test 01 01-JUL-1997

0

0

10 -1

0

10

time (min)

0

10 ' 10'

Fig. 3 Plot of raw drawdown data constant rate test Dl

~

El '--'

~ 0 '0 ~ co I-< '0

0.24

0.22

0.20

0.18

0.16

0.14

0.12

0.10

0.08

0.06

0.04

0.02

Recovery Test 01 01-JUL-1997

0

0.00 10-1

0

0

0

10

t!t'

Fig. 4 Plot of raw recovery data Dl.

Appendix D 11

10 ' 10 '

/'"'.

El '-.../

~ 0

] .... '0

Constant Rote Test E1 01-JUL-1997

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0.00 10-1

0

0

0

10

t (min)

0

0 0

10' 10 '

Fig. 5 Plot of Raw Data Constant Rate Test El

0.40

0.35

0.30

~ 0.25 El ~

~ 0.20

'0

~ 0.15 .... '0

0.10

0.05

0.00

Recovery Test E1 01-JUL-1997

0 0

10 -1

hO 0

0

10

tit'

Fig. 6 Raw data recovery test El.

Appendix D

10 ' 10'

12

,-. 8 '-'

~ 0 "0 ~

'" ... "0

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

Constant Rate Test D2 02-JUL-1997

0

0

0

0.00 10-\ 10

time (min)

00

0

0

0

10 '

Fig. 7 Raw data plot of constant rate test D2.

0.40

0.35

0.30 ,-. 8 0.25 '-'

~ 0 0.20

"0 ~

'" ... 0.15 "0

0.10

0.05

0.00

Recovery Test D2 02-JUL-1997

10 -j

tit'

0

10

0

0

0

10'

Fig. 8 Raw data plot of recovery test D2.

Appendix D

13

0

10 '

10 '

0.40

0.35

0.30

,-.. 8 '-"

0.25

~ 0.20

~ . 0.15 .... '0

0.10

0.05

0.00

Constant Rate Test E2 02-JUL-1997

0

0

10 -1 10

time (min)

o 0

0

0

10 '

Fig. 9 Raw data plot of constant rate test E2.

,-.. 8 '-"

~ ~ .... '0

0040

0.35

0.30

0.25

0.20

0.15

0.10

0.05

Recovery Test E2 02-JUL-1997

0.00 10-1

0

00

10 10 '

tit'

Fig. 10

Appendix D

Raw data plot of recovery test E2.

14

10 '

10'

0.15

0.10

0.05

0.00

Fig. 11

Appendix D

Recovery Test G1 04-JUL-1997

10 -1 10

tit'

0

0

10 '

Raw data plot of recovery test G 1

15

10 '

""'"' 8 '-'

~ 0

~ H

"Cl

Fig. 12

,-... 8 '-'

~ 0

"Cl ~ co I-<

"Cl

Fig. 13

Appendix D

0.25

0.20

0.15

0.10

0.05

0.00

Constant Rate Test K1 07-JUL-1997

I1 I

I1

V

10 -1 10

time (min)

f-. r-

10'

Raw data plot of constant rate test K1.

0.25

0.20

0.15

0.10

0.05

0.00

Recovery Test K1 07-JUL-1997

0

10 -\ 10

tft'

0 0

0

10 '

Raw data plot of recovery test K1.

16

0

10 '

10 '

data used for pumping test analysis piezometers A and B B

O.lOm .. T

2.70m

B

O.lOm ..

2.65m

__ J __ --,,-_-+_

....

0.38m

y

0.38m

• O.l4m • ..

A

.... ~

• 0.14 m

A

'-

pump intake 4.00 m

pump intake 4.00 m

start CRT 13.10 hrs 29/6/97

rest water level 2.80 m below TOC B

piezometer B b = 1.30 m L = 1.30 m

b L

•

start RECOVERY 14.15 hrs 29/6/97

rest water level 2.75 m below TOC B

piezometer B b = 1.25 m L = 1.25 m

b L

Note: 1. Adjustment of Rest Water Level was necessary because of water table rise due to flooding

Fig. 14

Appendix D

2. Recovery test becomes inaccurate towards the end because of the increasing rate of rise of the water table

Data on piezometer configuration of site AB.

17

PUlllpmg Test No. 1 Test conducted on: 29-JUN-97

B

Discharge 24,75 m)/c!

10'

10. 11 -........... , - .. The'"

Th~LS IS),) •

lO·3L-----C-------------------------------------" , BI

Transmissivily [m:/d]: 4.94 X lOt

Hydraulic conductivity (mid): 4.94 x lOO

Aquifer tlllckncss [m]: 10.000

Hydraulic conductivity vertical [mIdI: 4.94 x 10,1

----------------------------'

Fig. 15 Well test Bl, constant rate.

Appendix D

18

G

-- ---:;;-­"'f"

----':0 ----iT

idl .} 0UJ6~) ;:TiJlW:;ij 'fiji.Y~o8-­

--STlTi"::IC--!j-,-':)O~I';'-'

;)-_-;,;L}':iI':---, ) ,\}:.i6l)J· .. ·---··-··----------­

;F0Toj--;:-

'~.\qy ----~~0if5- ..

SI

DisI311CC (rom 11:.: pumping ".\'d (} ,i80 III

··"--·-·{rT~-O-·----- --.

-lr':-~-5

-""~"<J\jiT -;T.l':lu- --------.--.---~-:'\)"'iir ----~---Ir~-~~------

-- --~:-\jij3- ----------------iY .. i93----··-·· 2, ~1<)6

""'---"---'--~':~'iij"- ----Tf97----- -_. -- ---------i.l--l\~lli:G - .. _--- ;ID-:;-Y:3' .. - .. ·---"·--2-,'Fi7--~------ If"En- ----- ------- --. __ .. _---

- ;f0:rrr;~-' ---.----~. 99r-- 0-:19-1 . - .. _.--.-. - -(fJfT)TT

Fig. 15b Drawdown data well test Bl, constant rate.

Appendix D

19

Pumping Test No Test conducted on 29·JUN-97

B.rec.

Discharge 24,75 m'fd

Pumping test duration. 004514 d

vt' 10° 10'

0,00

002

0,04 "' '.

006 ~. ..

• 0,08

I '. 0,10 .....

• 0.12 •

OH

0.16

018

0.20

" Transm,ssivity (m>fd): 746 x 101

Hydraulic conducW'ty [mid): 7.46 x 10°

Aquifer thlcXnES$ [m). 10.000

Fig. 16 Drawdown plot for recovery test Bl.

Appendix D

20

Pumplr:g Test No

B rec

O,scharge 24 75 m'/d

Stat,e water level: 2.750 m below datum

Time from

end of pumping

[d[ O'6{)035

2 000069

3 0,00104

4 0.00139

5 O,Gm?!'

6 0,00208

7 ..

'0'002'43

8 '0,66278

9 0,OQ312

W 0,00382

" 000521

12 0.00799

13 0.01076

14 0:0,'4'24

15 ' '6'0'1701 li§"" (:i"Oil'i8 ,7 ' 18

.. 0',02951' 19 003368

20 0.03785

21 004201

22 0.04896

23 0,05590

24 0,06285

Water level

, 2 880

"i880

2.870 2.865 2.860

2.855 2:855 2,'853 ' 2,851 2,847 2840

2835 2.830

2.820 2.820 2.811

2,802'"

28CO . 2.790

2790 2.780

i.77o 5. 770

Test conducted on 29,JUN,97

B1

Oistance from the pumping well 0,380 m

Pumping test dura~on. 0.04514 d

drawdown

o:i':';o 0,130

'-0.120

0,115 0:110

0105 0.i05 (j,103' O:{Ol 0,097 .

0090 0.085 0'080

'0:070 "--0:070

0,C61 0'.059" o'o"si-0,050 0,040

, 0,040

'0.030 "0.020 O:CJ2D

Fig. 16b DrawdoWJ] data for recovery test B1.

Appendix D

21

Corrected

drawdown

0.129 0.129 0.119 0.114 0:109 ' 0:104 Cl.1-04

--"0"·02

-0",100 'a.o9i'

... 0,090

0,085 0',080

'0:070' 'o.oio~

"",- , 0.66(-, -6:059

'0.052

0050 , 0040 "0'040 '

0,030

0.020 '0020

Pumping Test No. 1

8.rec

Discharge 24.75 m'/d

10'

000

om

0.04

0,06

0.08

I "0 0.10

0.12

0.14

0.16

0,18

0.20 : 81

Transm'S'i;lvity (m'ld): 924 x 101

Hydraulic conductIVIty (mld1: 9.24 x 10°

Aquifer thickness [m1: 10,000

Test conducted on: 29-JUN-97

Pumping test duration: 0.04514 d

ut' 10' 10~

Fig. 17 Drawdown plot for recovery test Bl (reduced number of paints).

Appendix D

22

Pumping Test No

B.ree

Discharge 2<: 75 m'/d

Static water level: 2.750 m below datum

Time from Water level

end 01 pumpmg

{d] [ml_ 1 0.60069 j 0'00104 3 . Cl 66139

000174 0.00208

6 -0,00243 0.00278

B 000312

9 0,00382'

10 000521 11 000799 '12 ' -'001076

----'iX' ---o~6i-42'4'

14 0.G1701 15 0:02118 16 002535

2,880 iS7(j-2,865

2.860 '2855

:2 855 '2.853

2:851 i'-S4i 2840 2:s35

2.830 2,820 2,820 2S'11-

2.809

Test conducted 01'1', 29,JUN,97

Bl

Distance from the pumping well 0 380 m

PumplJlg test duraMn: 0.04514 d

ReSidual

drawdovm

[m)

0,130 0,120

0115 0110 0,105

0105 0.103 b.ibi 0097

'6"090' 0.085 -

0.080 -0'070-'

0,070 0,061 0_059

Corrected

drawdown

- '0:"29' 6:'-'-9'­

'""(5.'1'14'

"if{69" 0:'104

- '0::1'0:4-­'~-(j:r02

-o:i-oo"'~-

0.-09'7'-----~6:ooo-

--'(i __ ass "0.080 6~o76

'-------6._070' 0,061'

,._- 6:659

Fig. 17b Drawdown data for recovery test B1 (reduced number of points).

Appendix D

23

data used for pumping test analysis piezometers C, D and E TEST (1) 1/7/97

D E 0.007 m C 0.019 m zero level

0.19m surfoce start CRT

13.55 hrs 1/7/97

rest water level 1.073 m below TOC C

1.073 m

Note:

....... 0.47 m 0.225 m

pump intake 2.10 mTOC

piezometer C b = 2.31 m L = 1.48 m piezometer D b = 1.29 m L = 1.29 m piezometer E b = 0.96 m L =0.96m

b L

1. Water levels of piezometers D and E have been corrected by resp. -0.007 m and -0.019 m to reduce them to the same level as TOC C (see Appendix A and B)

2. A level correction of 5.91 x 10-5 m/min has been applied to compensate for rising water level (see Appendix C).

Fig. 18 Data on piezometer configuration CDE (test 1).

Appendix D

24

Pumping Tes! No. Test COnducted on- 01 July '997

O-CRT

Dlsch<Jrge 16.14 m'fd

Fig. 19

Appendix D

"y 1°,.' ______ ~lO~· __ ' ____ ~1:O·_2 ______ ~120_·' _______ lCOCO _______ 'COC' _______ 'COC' ________ 'O_' _________ 'O·

102 r

TMr>

1 t~e.s (Sy)

1O.3L-------------------------------°

Transm'SSlvlty (m'/d): 2.56 x 101

Hydraulic cOrlducttvlty fm/d) 5 12 x 10°

Aqlllfer thlclmess [m)' 5.000

Hydrau:ic conductivity vertical (mId): 5.12 x 10'1

Drawdown plot for constant rate test D1.

25

Pumpmg Test No

O-CRT

Discharge 1614 rn'ld

Static water level- 1 073 m belOW datum

Pumping test durallon

[dl 0,00052 0_00087

3 0.00122 0"00156

5 0-C0191 6 -0,00226 7 "0_00260 13-- 0:00295 9 -6:00330

10 . 6'00-382"" 11 0,00521-12 000729

13 -001076

" 0_01424

15 0,01771 16 002118

17 0,03160 18 0,04201

" o 0521!3

20 006285 21 o C6875

Water level

1,113

1_143

1.173 1-.188 1--',98 i:21'3--1',218

. ---1-i33'

1 289 1 299 1 313 " 315

- 1.328

1337 {3'42-

1 341

1 342

Test conducted on 01 July 1997

o Distance trom the pumping well 0 470 m

Drawdown

(m) 0040 -o-,oio -o',-bo

.. '61-'5' 0_12'5 0,140

-- cu,j'g '0'."160"' -'0.1-60 i:i.1-io· - -0"-85

". 0 20i

0.216 0,226 0240 0242 0,255 0264'

'0269

'0.268 0269

Fig. 19b Drawdown data for constant rate test DJ.

Appendix D

26

Pumping Test No 1 Test conducted on: 01 July 1997

Discharge 16. ~ 4 m'ld

Pump;ng lest duration: 0.06875 d

ur 10°

0.00

0,02

.!'!. 004

0.06

0.08

I 0.10 '" • 0.12 •

014

006

018

0.20 D

Transmls$lvity [m'ldJ_ 336 x 101

Hydraulic conductivIty (mid)' 6.72 x 10°

Aquifer thickness [m)- 5.000

Fig. 20 Drawdown plot for recovery test D1.

Appendix D

27

Pumping Test No

D"REC

Discharge 1614 m'ld

Static water level' 1 073 m below datum

1

2 j ~

6 7

8 9

Time from

end of pumping

[dl 000052 0.00087

"0:00122 "0'OOi56 ,) oo'{9i 0,00226 0.00243

0,00295 0,00365 0,00503 (i00712'

._- ()~Oi05if"

0:01'39'f" o~O'i"753 002101 003142 00':184 0,05226

Water level

1.269 1 239 ,',209

1.199 ,-""94 1 189

1 184

1 181

1 172 i "162

1""'-2: -""111

"1:098 1 095

Test conduoted on 01 July 1997

D

D'stance from the p(lmp,ng well 0.470 m

Pumping test duration 0 06875 d

ReSiduat

drawdown

[m] 0196 0166 0,136

0126 '0121 0_,",6

0111 0, lOB

0099 0,089

'--6,cai' 0067'"

" 'Cl.MY"" 0,'052 0048 0,038 0_025

0022

Fig.20b Drawdown data for recovery test D1.

Appendix D

28

Corrected

dr~w<lown

{m] 0192

0163 0, i'34'" 0'i"24

"0',1'20 6115 0,110 0,"07 " 0,0"98 O,08S' 0,080"" 6:00'1'" 0'051"""

" era's;'''""" -'0,04"S 0'038 0025 0,022'"

Pumping Test No t Test cOrldl.lcted Orl. 01 July 1997

E-CRT

Discharge 16.14 m'/d

tdy

to,','_; ___ ~10:'_' ___ ~10:'_' ___ ~'0~'_; ___ ~'~01 ___ ~'~0~; ____ '~O~' ____ t~O,-' ___ -::;'0' 102 r

10'

10'

" <

<0,

10"

1O.3'----------------------------~ E

TransmlSSrYlty (m'/d)· 1.81 x la'

Hydraulic conductMty (Ill/d) 362 x 10°

AquIfer thickness [m)· 5000

Hydraulic conductivity vertical [mid)· 3.62 x 10-1

Fig. 21 Drawdown plot for constant rate test El

Appendix D

29

Waterloo Hydrogeologlc 180 Columbia SI. W

Pumping Test No 1

E-CRT

Discharge 16 14 m'ld

Static water level: 1 071 m below datum

Pumping test duration

Id] 0,00035

2 0,00069

3 O.OO1·O4~

-iio61"3g 5- , "QOO1'7'4'"

··0.0020S _·0:00243

8 ..

O_OO27f3' 9 .. ---0'-06347"

,0 '0.00486-

" 0,60694 .

" - 0.0'-04-2

" .. '(5,01'369

" 0,01736

" ci,02083

" 0,03125

" 0",04167

" 00520$

" 0,06250 20 0.06875

Pumping test analysIs MOENCH's met.'1od Unconfined aqutfer

Water level

Im] 1.1";",

1 171 --i ,201-

-- --,-.-::a§ '1':-246--­

--'-,251

,'_286 --1::31'{

',:"327' - - " 357 ' - -1.35i

1.362

1,368

1_382 " 390

1 387 1_396 1:395

Date. 02,10,1997 appendix. Page 2

ProJect: aRC Site

Evaluated by' 08

Test conducted on 01 July tg97

E

Distance from the pumping weil 0,225 m

Drawdown

Im] 0_040 0,00

b:130 '6:i'55--

---<:i.'i'is '~--6~i'8'O

O~'95 -0:.200

0.215 0,240

0,256 0_286 '0 -286

0,291 0,297

0,311

0319

0,316

0,325 0_325

Fig. 21b Drawdown data for constant rate test El.

Appendix D

30

?umplng Test No 1 Test cor.~ucted on. 01 Juiy 1997

E-REC

Pumping :eSl OUr3!;Or. 0 06675 d

Ut'

WO

000

003

--006

009 . " 012

I .~ 015

018

021

02'

027

030 El

TransmlSSIVI\y {m'/dJ 2.87 x 10:

Hydraulic conductivity (mid] 5 7~ x 1C~

Aqu,ier thlc~ness (mj 5 COO

Fig. 22 Drawdown plot for recovery test El.

Appendix D

31

Pumping Test No 1

E-REC

Discharge 16 14 m'ld

Sta~'c water level: 1,071 m below datum

1

2

5 ,. 7

8 -9'----

---'0 . 11

-12' 13

. 'i4 1'5"

16 17 i8

Time from

end of pump'ng

Idl 0_00035 000069 0,00104

0.00139 0_00174

0,00208

0.00243 0:00278

'~-Om3'4-7

'0,00486--­-"-'O~0669"i"

--6.0104-2 . -0:01'389

- "·'0'.-0'-736'-

'0.02083 '0,03125 004-167

0,05208

Water level

Iml 1 337 1'267

1.227 1,207 1_197 1.194'

""1",-187" --- ':185-

1:1'81---1-:172-1.160

--1~'1'48

-1~1"j8

1'1-28 "rl'24--

1'110-

--1,105' '1 096

Test conducted on: 01 July 1997

El

D,stance from the pumping well 0,225 m

Pumping test duratIOn 0_06875 d

Residual

drawdown

,(m),

Fig.22b Drawdown data for recovery test El.

Appendix D

32

Corrected

drawdown

Imj 0_259 0:-19'2"" 6:'i54-­O-i34 . 0,-124-- . 0.121 6:1"5-

0.076 -o_ooi----0,057

. "O:C)53----ii039 O~O-34--

6~025 .

Waterloo Hydrogeologic 180 Columbia St. w W~lerl<>o.O.'(ano C"na~a

pn (5t9JI~6. ,198

PUmPH"lg test analysIs MOfNCH's method Unconfined aquifer

Date' 02.10.1997 I appendix. Page 1

PrOJect: ORC site

Evaluated by: AG

Pumping Tes! No. 1 - Test conducted on 01 July 1997

O-CRT

Olscharge 16.14 m'ld

Fig. 23

Appendix D

,M'S iS~) TMel~

10·)L------------------------------l

E

Transmissivity [m'fdj: 2.03 x 101

Hydraulic conduc~vlty [mid]' 4.07 x 1cP

Aquifer th,ckness [mJ. 5.000

Specific yreld: 1.99 x 10"

Hydraulic conduc~v,ty vertical [mid) 203 x 10°

Composite drawdown plot for constant rate test Dl,El.

33

Pumping Test No. 1

D-CRT

DI~charge 16.14 m'/d

Static water level: 1,073 m below datum

1 2 .

3

18

21 . -

Pumping' test duration

(iOOO52 -o_ooosi ci:OO'f22--- ,--

, '0,0015-6-- ..

-ij,0019;---0:50226

0.00521

0.00729 'O,OiO~76- -

-- --0'_05243 .. , "'0'-06285

'0,06875

Water level

. [m.L

Test conducted 01'1- 01 July 1997

o Distance Irom !he pumping well 0.470 m

1.113-- , -1~i-43'

1''''73 1.188 -i-_198 --i~21j

1'.258 -i':ii4 -1,289

Drawdown

--6:040-­·0.07i:i·

., 'd,'i'oo 0.115

0_125 , -0.140'

---1-.299---- ,---

0,185 0,201 0_216 - ~

'O_i2'f;--0':24'0--

1.'342 ,. --(3"4'i­,',342

-"0:269 -0268

0.269

Fig.23b Drawdown data for composite constant rate test Dl.

Appendix D

34

Pumping Test No

D·CRT

Discharge 16 14 m'ld

Static water level: 1 073 m below datum

1

2 3 ,.-

4

5 6 7 8·

9 10

11 . '12 .

13 14

15 16 17 18 19'"

"20 .

Pumpmg test duration

J?) __ . 0:'00035 0.00069

------0,00104·'--

-O:oojj'g'''' -'i5~OO'1'74

-6:0tJ20fl ,. 0:06243"" 0:00278 o:6034'f 0-00486 '0.-00694 -

"0:01042--0.01389 0_01736

- 002063 0_03125 0.04167 '0,0520/3' -O:062Scf-0.06875

Test conducted on: 01 July 1897

, Distance rrom the pumping we!1 0.225 m

Water level Drawdown

.J~L . 1.111

--- -----1:t71 .. -----·---~201- --0.128--

... -- ---------:1:"2'2i3""· -'f:24'S

_·· .. ----'·jS'l'· fis6

"'.271 -1-:286"

""1.-311

. 'i":327 -- --usi

. ---O.1·53-~ <5:"i73-­

--ifi"78 '0,'1-93 0.198

"0:ii3 0.238

--'6554' .- ... -0:284-

-·1-.357 0.284

1.362 0:289 --,j68 0,295

1.382 . 0.309 --1:390" 0:31-;'-

;-:;;87 0_314 1-:396-- _·"-6:323-

_ ............... ·.-.. -.. _~.-1--:396·'~·c- _ _ __ .. _ .. _-_--__ -.0-,T23 .. -.. ~--

Fig.23c Drawdown data for composite constant rate test El.

Appendix D

35

data used for pumping test analysis piezometers C, D and E TEST (2) 2/7/97

D E o,cm r:' 0,019 m

0,19m e zero level

surface start eRT 10,17 hrs 2/7/97

1,03 m reor water level 1,03 m below TOe C

,.

Note:

-'Y: __ , r-~"".

, .......................... " •

0,47 m 0,225 m

pump intake 2,85 m TOe

,. "--

piezometer C b = 2,35 m L = 1,48 m piezometer D b = 1,33 m L =1,33m piezometer E b= 1,00 m L = 1,00 m

b L

1, Water levels of piezometers D and E have been corrected by resp, -0,007 m and -0,019 m to reduce them to the same level as TOe e (see Appendix A and B)

2, A level correction of 2,49 x 10-5 m/min has been applied to compensate for rising water level (see Appendix C),

Fig. 24 Data on piezometer configuration CDE (test2).

Appendix D

36

Pumping Test No 2 Test conducted on: 02-JUL Y-97

o Discharge 16.07 m'ld

10'

TM,s (Sy)

10.3 '-______ -'---______ --'--______ -'-___ -'---__ -1

,0

TransmlSSlvity (m'/d): 2,27 x 10'

Hydraulic conductivity [mId): 4,54 x 100

Aquifer thickness [m): 5.000

Hydraulic conductivity vertical [mid): 4.54 x 10':

Fig. 25 Drawdown plot of constant rate test D2 ( y= lxl09).

Appendix D

37

Pumping Test No 2

o

Discharge 16.07 m'fd

Static water tevel: 1,030 m below datum

1

2 - 3-'

,. ---'-4"' -'''-'5

6" 7 8 9

1'0'" .. , 11-' '12'~--

Pumping test duration

0_00052

O'-OCYi04 O,O{)t2S-

'--6'-OO156-~--" --6:ix119'1-0,00226 0.00260' 0.00295 6,-00365'

----13-------~":-" ---15 --16 - i7 . i'8 .

19 . 20 21

-22--23'-

., "'ii04184"" - , '0.05226'" 0,06267 0:08351

.... e):';'2517 , 0:16684 0.20851

INater level

, 1,093

-1':123 '-1,-'-43'

-1".-158

Test conducted on: 02-JUl Y-97

o Distance from the pumpH19 well 0,470 m

Drawdown

0.063 0:093' 'o:l"1}'

.. -6:1'28' -{:,'73 -- , 0.1'43

0,'-4"8--6,153 '0,163

0.i73

" .. -----1:178' U83 ':193

'1-:203

'{31-S ',':-321' "1':-329--

1 338 {3'42-

','_343

'--6:285' 0,291

..... '0",-299

ii30a .... '0:31'2'

0,313

Fig.25b Drawdown data of constant rate test D2 ( y= lxl09).

Appendix D

38

Pumpmg Test No 2 Test conducted on: 02-JUl Y-97

o

Discharge 1607 m'ld

td, 1o,' ______ ~'O~·, _______ '~O~·' ______ ~'0C_ ______ C'CO_' ______ C'COC' _______ 'COC' _______ 'COC' ______ --;'0'

10' r

10'

10°

n <

T~".:;

10.1

1Q"3 L ----------'--------------------' o

TransmiSSlVlty[m'fdJ: 3.21 X 10\

Hydraulic conductivity (mId) 6 42 x 10°

Aquifer thickness (m): 5.000

Hydraulic conductiVlly vertical (mfd): 6.42 x 10·\

Fig. 26 Drawdown plot of constant rate test D2 (y=3).

Appendix D

39

Pumping Test No, 2

o Discharge 16.07 rn'/d

Static water level: 1.030 m below datum ---- -_. -- - "-'.--"

Pumping test duratior'l Water level

Idl

20

-0.00052

0,00104 0.OOi-2S--

000156 -0,OC)191

"0:00226

0.00260

0.06295 -0. 00365'-" -­"0:00503' -- ~--.,,----'". -

-0~6i'i53 0.02101 0.031'42 -­

'004184 0.05226-

, o.ooi67 0.08351

--6:"2!hi 016684 0,20851

1.093 1,123 1'.143 i,158 . -1."73

--":183" -i.'{s3'

""1-,'203--

------',--:-274' ' . '{:27"7

._, i:'296'

... _._---:_----_ .. _--._,-_._---

Test conducted on. 02-JUL Y-97

o

Distance from the pump,ng well 0.470 m

Orawdowr'l

ImJ 0.063

0,093 0.113

'0128 "0.-'43'

OX53 -­-6:163 (j'{73 (i:191--

-·-··-6:203-­"'--'0:223

"0-2-4i '0'266

0.275 0,285 '0,291'

0'299

o:3Oii --r:;31i 0.313'"

Fig.26b Drawdown data of constant rate test D2 (y=3).

Appendix D

40

Pumping Test No 2 Test conducted on: )2-JUL Y-97

02 recovery test

Oischarge 16.07 m'/d

Pumping test duration: 0.20833 d

vr ,,0

0.00

0.03

0.06

0.09

0.12

I '. 0.15 I"ij" ------.~-.~-.-

• 0.18

0.21

0.24

0.27

0.30 ·0

Transmlssivity (m'ldJ: 3.07 x 101

HydrauliC conductivity [mid]: 6.14 x 100

Aquifer thickness [m]: 5.000

Fig. 27 Drawdown plot of recovery test D2.

Appendix D

41

Pumping Test No

02 recovery test

Oischarge 16.07 m'/d

StatiC water level: 1 030 m below datum

Time from Water level

end of pumping

-~-1-'­

·'2"--

J~L [m} . 'O,OOOg2'-"-~-' -1~260--

1230 ····1~204·

'-',','19i" '1-1'86 ,'181

3 4 5· ·6· ., ,. -g-

',6--11 12 . 13

'14 -15· 1-6 -

'1'("

18 19

-'6RiOa'r"'-" oj501'22--~'

. - -oXiOl's6 0.00;-9,'-' 0:00226 0.00260"-0.06295 .

--0.00365 -6.60503-- -

'--6:6{Wfr . 0.-01659

0.01>'106

0.01753 0'02101 0':031'42'--­"1i"04184

"'-----(f05226--(Y06267--

" 176

1.,fi 1.161

""'-'49 _. - 1'--{36

,: 121

1.109 1 101

-- ',,'093

·rOl7 -loio l~66r"

---1~055

Test conducted on. )2-JUl Y -97

D

DistanCe from the pumping well 0.470 m

Pumping test duration, 0_20833 d

ReSidual

drawdown

_, ________ ~L ""0.230 -

- ~O~-200---·0:-174'---

. ifl-sf'" 0-156-0.151 0146 0.141 0,'131

. 0:11-9

0.106" '0_001 0,079 0:071 6:663 (5,047

- -----0:040-""0:03-1-

--- ---"0.025'

Fig.27b Drawdown data of recovery test D2.

Appendix D

42

Corrected

drallldOIll()

___ J~) ''''0:225--

-- --- --- -6-:-196" --0.171 -i)'iS8 . -o.l-M-· 0:'-49-­'0,-144--"

"(;139--

-6:1-29 "0''-'11;)'-

0"'05---­-0-090'

. 0_078 0,070--'

, '0:063--0:047

~-"[i546-

0.03',---­O:025~--

Pumping Test No. 2 Test conducted on: 02-JUL Y-1997

E-eRT

DIscharge 16,07 m'fd

Fig. 28

Appendix D

Idy

1or.' _______ 1~O~·' ______ ~'O:·_' ______ ~'O:·_' ______ C':OO ________ 'CO_' _______ '_O_' ________ 'O_' ______ ~'0' 10'

w,L-------------------------~ , E

Transmissivity [m'fdj: 143 x 101

Hydraulic conductivity (mid]: 2_86 x 10°

Aquifer tntcKness (m): 5.000

Hydraulic conductivity vertical (mid]: 2.86 x 10-1

Drawdown plot of constant rate test E2 ( y= lx109).

43

Pumping Test No. 2

E-CRT

Discharge 16,07 m'/d

Static water leve\: 1.030 m below datum

3 4

Pumping test dUration

0,0003'5 0:00081' 0.'00116"

MO~OO1'39'-

Water level

0:001-74- _ ~_~_~~~

1.086' 1.-141

Test conducted on' 02-JUL Y-1997

E

D;stance from the pumping well 0.225 m

Drawdown

o_o'ss 6111 -6.151 0_166

0.0020'8-- --"'6:00243 .... ~ ..• '.;;,; .. ~

- "0:,'81 '0,196 . -0,206--'" E206 -i)'231

8 9

'0

" "

'"'1fr--­---16--

" " '19--

Fig.28b

Appendix D

6,ooils 0,00347"-­

-- 0_064-66 6.06694'

'6,01'042'-

-0:66256- M_

0,08385 - -0.12500--0-'-6667"

, -- 0'.208'33

1:ZS1 1~276 '

'1.291 -rS66 -

-i- 381--(300-'",jgi-

.. ··-0.246 0261

-'-6,2i6'" 0-.291-­

-'O~302 - --Q30r--'-"'--'0:324---

0,339-­-0',345-----0.351"' 6,360 -b,367 .

6.'37'i -oj7"(" -

Drawdown data of constant rate test E2 ( y= lx109).

44

Pumping T e:.;: No. 2 Test conducted on: 02-JUL Y-1997

E-eRT

Oischarge 16.07 m'ld

~::.:::::;;;:;;:;:;;;;;",~", .

/.

1 cl' /

" " Thel$.

10"

1O.3L-----------------------------.J E

TransmlsSlvity (m'/d): 2.27 x 101

Hydraulic conductivity (mid) 4.54 x 100

Aquifer thickness [m)', 5.000

Hydraulic condlJctivity vert,cal [mJd) 454 x 10

Fig. 29 Drawdown plot of cqnstant rate test E2 (y=3).

Appendix D

45

Pumping Test No, 2

E·CRT

Olscharge 16,07 m'td

Stabc water level: 1.030 m below datum

1 2 "

3"

'4" .. 5' ,"

'7' 8 9

'ii)" 11 12' '{3 .

'14 .. 15'

'l's'" "'11'''

'''--'8'­-1'9 ',. io-2i--' '22 . 23'-

Pumping test duration

.. J~L. 'O~i50635'-

"0:0008"; 0.OO11·6~'·-·

0:00139·" 'O,OOW4

'·'0.00268 0,00243

0.00278 (f00347

.. ri6(J48s' 0'.00694 0.61042' 001'389

. "0',0'-736' -"0.02083--

0.03125

.. ···-'0.05200-·_·_-­'0,002sO"~--''"---'~''

. -''''6.08385

O:.-i2Sixi-'--- -'-"-O~1666i

ri20833

Water level

".-226' -,'.236--

1,236 . -(26i

'--1,276-­--i-291'" 1.306

-1':321' "

Test conducted on: 02·JUl Y -1997

E

Distance from the pumping well 0,225 m

Drawdown

. O~056'" -o:-,'1'i

0,181 0-.1'96

0,206 '0.206 0231

. i.f246 6.261 --ri276

-"0:291' --- '~1j'32 ,- -- -0.302

--1:337 --6-567 - --,':3'54- . '0:524 ..... ' -'------

---'--1.369- -6.'339----'-'-·-T375"-~'·-----'--~·~- .- --'ij,341f'-'-~-----

-----""1·:381 .. --~---·-··'- .. "~-- -o~35i--··

·1-:396-.. -----'.----, .. -·--'- - --'(}360

---i-j-gi --ii367 -1461 0,371'--·1".-4'6i' 0.371

Fig.29b Drawdown plot of constant rate test E2 (y=;3).

Appendix D

46

Pumping Test No 2

E2 recovery

Discharge 1607 m'ld

10' 0,00

003

0,06

0.09

0.12

I 0.15 .. 0.18

0,21

0.24

0,27

0,30 cE

Transm,sslvrty (m'/d). 2,66 x 10\

•

Hydraulic conductivity (mid): 5.33 x 100

Aquifer thickness [m)' 5.000

Test conducted on: 02-JUl Y-1997

Pumping test duration: 0.20833 d

Vt'

• •

• • .. '_.! .--

Fig. 30 Drawdown plot of recovery test E2.

Appendix D

47

Pumpl~ Test No. 2

E2 recovery

Discharge 16.07 m'/d

Static water level: 1,030 m below datum

~-~'-4---

-5-- . ; 7 ,. 9

10

11

12 .. 13 "

14 ---'5 ---

18

17 18

19

Time from

end of pumping

(d( 0,00035

"OXlOOS§ ·'0.00104 ~O.OO-iS9-·-·

---6:00"17:C" ---000208 . 0:00243" 0.0027S b 0034f 0-_00486

--'000694' 0.01042 0(:11389 0_01-736

Om083 0,03125

0,04167

005208 0.06250

Water level

"':321 -----'1_-261'"

-·-~---·12-·t6-

Test conducted on: 02-JUl Y ·1997

E

Distance from the pumping well 0.225 m

Pumping test duration: 0.20833 d

Residual

drawdown

.!~! '0.291 O~231

-- - 0" --"'1-:186------ -"~----~--~O,156---' .-----1:"1-79-1-.-i76

- '1:i69 "1:1-S3 1-.-151'"

'---'1:134-{"'-2"

".-'-06 -'.102

1.087 1 072 i',062 -i~053

0.149 - (i'i46---i:l.-'39

0.133 0:12"1

0104 . '0.001'

iio76 '-0072

0,057 0.042 0,()32 .

0.023

Fig.30b Drawdown data of recovery test E2.

Appendix D

48

Corrected

drawdown

"0,283 , 0,226"

... --O.-f83 .. ·· "-6:100--­

. ----0: i 54---'O_14f--01'44 0_137

-0~i'31

0120

0,103 0:090 0_075-' 0071 0,057

" '0,042 0.032

-0:623" 'o_o,"s--

Pumping Test No. 2 Test conducted on. 02-JUL Y-1997

E-CRT

Discharge 16.07 m'ld

Fig, 31

Appendix D

Idy

1o,' ______ 1~0_·' ____ ~10~·' ______ 1~0~·' ______ '~0_O ____ ~1~0_' ____ ~10~' ______ ~'O~' ______ '~O· 101 r

10'

/ , -----~----------,--------

1O.,L------------------------_..J ,E o

Transmissivlty (m1fd) 1.80 x 101

Hydraulic conductivity (mid): 3.61 x 10°

Aquifer thickness (m): 5.000

Specific Yield: 4.45 x 101

Hydraulic conductivity vertical [mid)' 3.61 x 10'\

Drawdown plot of composite constant rate test CDE2 ( y= lx109).

(drawdown data are the same as for Fig, 32),

49

Pumping Test No. 2 Test conducted on: 02-JUL Y -1997

E-CRT

Discharge 16.07 m'/d

Fig. 32

Appendix D

10' - .. ·--~f:;;,:?3:;~"~''''''-~ .. lE'

t'

1O.3L----------------------------1 , E " D

Transmlssivity (mlld)' 2.55 x 10'

Hydraulic cOrlductivlty [mid]: 5. to x 10°

Aqu,fer thickness (m]: 5.000

Specific Yield: 2.80 x 10.1

Hydraulic conductivity vertical [mid) 2.55 x 10°

Drawdown plot for composite test CDE2 (y=3). Note that parameters band L for piezometer E have been changed slightly (see discussion main text).

50

Pumping Test No. 2

E-CRT

Discharge 1607 m'/d

Static water level: 1 030 m below datum

1'----

2 ... -. "j

4 5" 6·

7 -S-" 9

Pumping test duration

--6,00635" ci:6008i

'-000'-16' 000139 0.00174" 0,00208 0.00243

.~ '0.00278" . "- ·····-0 .. 0034'r

Water level

_._[~1 1.086

"1:1"41 i.'18'1 . 1.1-96 1.211

"'--T226 -"i"2:36'-­

"--'i':}'36'

Test conductoo on: 02-JUL Y-1997

E

Distance from the pumping well 0.225 m

Drawdown

- '0056 0.111 0.151' 0.-166--0.181

--o.-i"ss ---"0:206-. 'a.i'Off-'

'lO-~'­

. ----:rr- ~u. .-~~­

-13--

0,004$6=;--,-____ _ 0,00694 1,291 -- ---(:i":261----

--6:01042----·-----·--~--1_:300--~------ ____ 0.276 ---0,01389-- -··----··--·-~--'__U21------- -O~291--·----~--

14 _. o~(hi36' {s"-- '(':0208:3'--'lS'- '6:03125 17 . '0.04'1(37" 18 . O.0520tf' i 9 .. -6.06250'

-"--i6-~- ------ '---... - '-'--'0:08385' '--21'-' "6:12560'

22·

23

(i.16667-0.20833

---~332-

··--i537 1.354 1.369

- '{jj5

-- f381 r390

····_·1397' l'A01

1 401

_ .. _" "._"- "-_"-",0,"":0;,2; ___ .""""." ___ ---------1

'0.339" .. '0:345

0.351 '·O.36iY· 'b~36i

- -- --0.371------- -----

0.371

Fig.32b Drawdown data piezometer E composite plot CDE2,

Appendix D

51

Pumping Test No 2 Test C<lnducted on: 02-JUl Y ·1997

E-CRT o

Discharge 16.07 m'ld Distance from the pumping well 0.470 m

Static water level: 1.030 m below datum -"~~~ping'le"~tdWa~"~'-~'--Water le~I---' ------.----'.O~~d;;n--'------·-·-·

1 ,. j.

4 ·s ---S" 7

'S---9

10·

11

12

(9.1. 0.50052 0:0010'4

..··0.00'1"25 0.00156

. 0.00191" .. -0-.00226

'('foo2"60' -6.-00295" -o.oo3sif 0.00503 . 0,0::J712 0.01059

. '1.143 1.158 1.173 -,-We 1:1S3··

.. ··1 ~'--93 j-.203·

',:221 --1233 . - 1.253

0:063" 0.093

- 'o,l'i"3 0.\28 '0-:-143

'li148" , 0:153"

. '-0-:i63-0_173 0:,91

. 0.203

6.223 13' - O~01'400' 1.'26'4 '0.234'

-~i4-~-' "·-o.01753-~-'---------1~274 '--'-- .. -·0.244-------- ..... ---- -- . ---is:- . --- ----0.62-,01--· --·'----~--1Ti1---·-·------O'2·4-7-----'--··-·------1f--"·--~--M31-42---·----·--1296'--·--·-----0.266""----,,-------.- .. ----.----

-17-·----"-----Q04184·-"-------'·--~5----·-------·----------0:'2"75------------··

---18-' ···---'0:"05226.-------.. ---------1-:3i-5----------- ~(i2s5-----'- ----. 0.06267 . 0_08351

'0:1'251'Y-0.16684

'O,208ST-

1,321

", 329

1,338 1_342

,. ----"' 1-:-343·----

-ii:i9', 0.299 ci:308 0.312

" -OS,"3-

----. --_ ... ,--_ .. - .. _----_ .. _-,------"'-------------_.----_. __ . ------.------------

Fig.32c Drawdown data piezometer D composite plot CDE2.

Appendix D

52

data used for pumping test analysis piezometer G G

• 0,14 m

jl.39 m

pump intake 4,53 mTOC

Note: A level correction Of 1,08 x 10.5 m/min has been applied

Fig. 33 Data for piezometer G.

Appendix D

53

startCRT 11 ,50 hrs 5/7/97

rest water level 3,53 m below TOC G

Test conducted on: 04·JUl Y-97 .-----"-~~.------- .~--- ~----.--.-.~~--.. -.---.-- --_ .. -.----_._--------"

G recovery

Discharge 8_67 m'/d

I -.

Pumping test duration: 0.12nS d

V1' O ,01 102 103

,o,~--------__ ----~~--------------------------------~ 0.00

0,01

0.02

0,03

0.04

0.05

0,06

0.07

0.08

0.09

0.10 c,G

Transmissivity [m1Id1: 3.86 x 101

Hydraulic conductivity (m/d1: 7,72 x 10°

AqUifer thickness {m1: 5.000

.. -.' • • " .-.~ -.

Fig. 34 Drawdown plot for recovery test Gl.

Appendix D

54

Pumping Test No

G recovery

Static water level: 3,530 m below datum

Time from

end of pumpmg

Idl '0.'00069

Water level

Test conducted on: 04-JUlY-97

G

Pumping test duration' 0,12778

Residual

drawdown

_.-.-J~L 1 j" . 0,00104

000139 0.'&)1'7"';'

--O~66208"

-- --3:6'-2'--0."082 0:682

3 4 5 " 6 "

.. ""'"7"

10

11 "-2 '"

1'3 --

14 --1'5'--""'6-. i'7' 18"

Fig.34b

Appendix D

-0:00243 (i,002-78 0,00347' 0_00486 '

'0,00'7"6'4 0_01042

--6:01389 -0,01736

--3:612 :3."612 3.612

-3.-E'-0-:?, 3,5'94 3"592 3.587

3581 3_577

3_571 '--'-'-Brrr

... ~;;;;.;.;"_""_" ""." ... "" "'-'---3:'564 ---- ------"3."55f

0.05208 ----0_00250""

3:55-2 :3:'549 '3'-549

. -(fOS2---0:082-'iii.i82 '0.'072 -"6.004-­

, 0,062

o_os'i --0_05(' -0:647 0.041

, ""0.037' --- --~6_634 - - --o_-62-7 .

0.022 ------6:-0"1·9----·-----

Drawdown data for recovery test G 1.

55

Corrected

drawdown

(m,!

.... "0."001"'-­-'O~081-­

"(5:00" ---0:001---'

'6:'o/i--­if 004-

'-0:062---0:057

---6:051-- -. --0.00

-'"0.041-'--­"'O~03r -0:-034---"(f02i-'0'-022 .. -o~o~ -0']19

data used for pumping test analysis piezometers J and K

0.19 m t J

... .,

• 0.14m. ;.

1.06m

.........

0.57 m

~umpintake 3.03 m

K

start CRT 09.16 hrs 7/7/97

rest water level 1.20 m below TOC K

piezometer J b =2.03 m L = 1.85 m

piezometer K b = 1.50 m L = 1.50 m

b L

Note: A level correction of 5.39 x 10-5 m/min has been applied

Fig. 35 Data for the analysis of piezometers J and K.

Appendix D

56

Pumping Test No. Test conducted on: 07-JUt. Y-97

K constant rate

Discharge 19.00 m'/d

Fig. 36

Appendix D

Idy 10.4 10.3 10.2 10.1 10° 10" 103 104

10' r-------------------------------------------------------------,

I The's (Sy)

1O.3'--------------------------------.J

TransmlSSlvity [mIld]: 4.78 x 101

Hydraulic COndUctIVIty [mid]: 9.56 x 10°

Aquifer thickness [m): 5.000

Hydraulic conductivity vertical [mid): 9.56 x 10.1

Drawdown plot for constant rate test Kl.

57

Pumping Test No

K constant rate

Oischarge 19.00 m'/d

Stauc water level' 1 200 m below datum

1 2 " j--

, '5 .. s'" ..". 8 --g---

-';"0 11 -----12--'---

-----i3---14 ' 15"

113" 17 .

"1'8'" --19 '

20

Pumping test dura~on

[dJ "0-60035 'O~00069

060104 0,00139 0.00174 .

. -'·'().'OO200"

-(i_00243 -0.00278"

_ .. -------6:00347

--~-·--o.6i'38ff-

0,01"736 , 0,02083

0.03125 0.04167 0.00250

"0_08455 -O~ci93i5

.-, Test conducted on: 07·JUl Y·S?

Water level

JmJ 1.270

1.330

1360 -(370

'-i-ilea' , ;."356-

- --t~393

"----i-398 --T405

.. -i'.'427-1:432 '1:433 ,-1 432 1',437 1.443

1.440 - 1 439

i- 433

K

Distance from ti1e pumptng well 0 570 m

Drawdown

[m[ 0,070

- 6,-130

0.160 0:,'70 -6:i80--

'-"o:iiY-6:232

"" 0.233 0.232

, '0.2:37 0.243 0240

0,239 0.233 ..

Fig.36b Drawdown data for constant rate test Kl.

Appendix D

58

Pumping Test No. 1

K recovery

Oischarge 19,00 m'ld

10'

0.00

0.02

0,04

0,06

0,08

I -. 0,10

0,12

0.14

0.16

0.18

0.20 ,K

• •

Transmissivity (m'/d): 4.72 x 10\

10'

Hydraulic conductivity {mid]: 9.45 x 10°

Aquifer thickness (m): 5.000

Test conducted on: 07-JUL Y-1997

Pumping test durabon, 009375 d

Vt'

•• . .. ~ ..... ~-.-.

Fig. 37 Drawdown plot for recovery test Kl.

Appendix D

59

o· .. -.'~.~.---.-~

Pumping Test No. Test conducte<l on: 07-JUL Y·1997

K recovery K

Discharge 19_00 m'fd Distance from the pumping well 0.570 m

Static water level: 1.200 m below datum Pumping test duration: 0.09375 d

1

2

4 5 "

s· 7 "

8 9

10 '1'"

--12--" .-.~.

--f4-lif' is"-17 fa ..

Fig.37b

Appendix D

Time from

end of pumping

[d] . iJ.0i:i035 -0,00009 0,00104'

. -6:60'i39 0.i:x51"74 0.00208" 0.00243 0,OOi78

"'0.00382 "0.0048'6

Water level

'1.380' 1.327 { 292 1280

1,277

1:275 1.27'2 des)"

-'"1.264'-----1'.258-

Residual

drawdown

.... ..irn! 6:180 . Q,,'ii-0.092 0_080 ooi7 .

. 6:675' 6_072--ri6ssi

'"-C),064 ····iJ:058---.. ·

----O:OCi729-.--------.. -,-::253- 0:053-~-'

.. ···----0.01"042---------.. · ---" .. ------'1.238------.-,,----·,---- --0.038'------'-'--- --.• _ .. - 0.01"389 --·-··-------·----------'"1,236-----·--------.. ··"------· .. ·-'0_036'----

--""0.01800 ... ----... --.,,------- --'1.23'---- -------------·-·~-b~o31··-·--. -----'·-0~0213'5--- --· .... ·1:224 .... ---- ·--------·----'0.02'4 .. "

0.03125-" '0:04167"

- 6.06250--------{:266-

1.i98'" -

"0:012 o_ooe

'=<),002

Drawdown data for recovery test Kl.

60

C;.Jrrected

drawdown

.. J~L 0,177

'''(i125 - -0.091----6.079--.. 0,076'

---6:074-----0.071' . ""0:0-69-­---0:064----

-- -0.056--0,053

-6.038 "o.03if "'0._031

--- .... -----~6._oi4--0.01-2-­

'~"ij.OO6-

~-6 __ 002

,

Fig. 38

Fig. 39

Appendix D

initial groundwater table

- 1h -- -- -..

H stabilized groundwater table I I .........

2r

s

Diagram showing basic parameters of the Zangar method (Drainage Principles and Applications, ILRI, Vol HI, 1974).

H

, , ,a ,

~ E

.~ 0.

-----i----.. '

! : a ,

---y----

___ .l ___ t _______ _

surface

initial groundwater table

.. - - - - - i- - - - - - pump intake , , : hlo , ,

.. - - - - -! - - - - - - bottom hole

Zangar parameters as applied here. h,o is the difference between the pump intake and the bottom of the hole, whereas hhi = h,o +a. Length a is half the distance from the pump intake to the initial groundwater table.

61

Zangar method input data

Toe screen TOe Toe Toe bottom depth length topscreen watlev pumpint H hlo hhi

(m) (m) (m) (m) (m) (m) (m) (m) A 4.73 2.94 1. 79 2.84 4.00 1.89 0.73 1.31 Cl 3.38 1.48 1.90 1.07 2.10 2.31 1.28 1.80

e2 3.3.B 1.48 1.90 1.03 2.85 2.35 0.53 1.44

F 5.18 i:~~ 4.16 4.07 4.95 1.11 0.23 0.67

G 4.75 2.84 3.53 4.53 1.22 0.22 0.72

J 3.28 1.8$ 1.43 1. 25 3.03 2.03 0.25 1.14

Q H ' hIe hhi k10 khi kavg dif

(m3/d) (m) (m) (m) (m/d) (m/d) (m/d) (m/d) A 24.75 1.89 0.73 1.31 25.92 28.21 27.07 1.14

Cl ·16.14 2.31 1.28 1.80 11. 48 15.81 13.65 2.16

e2 / 16.07 2.35 0.53 1.44 15.04 11.45 13.24 1. 79

F 5.00 1.11 0.23 0.67 16.67 12.65 14.66 2.01

G 8.67 1. 22 0.22 0.72 26.72 18.54 22.63 4.09

J 19.00 2.03 0.25 1.14 31.99 16.90 24.45 7.55

Appendix D

62

Calculation of hydraulic co'nductivities, method Zangar

program zangar; {$R+} {$N+} uses graph,crt,printer; type glnar=array[1 .• 25J of single; glint=integer;

var i,j,k,xc,yc,istart,iend,iz,iff,mstart,oldm: int7ger; ndata: glint; fn,fn1: string[80J; datafile,pfile: text; graphdriver,graphmode,nda: integer; color: byte; Igx,lgy: single; x,y,y2,yclay,ysort,ygrav,outfl: glnar; Q,r,L,H,hh,C,cond: single; ypl, ypn,xx, yy, ystart;-astart, sum, clay, sort, gray: single; outp: array[l .• 100J of single; dm: array[1 .• 12J of single;

label 1,2; procedure spline(yp1,ypn: single; n: glint; var y2: glnar); var

i,k: integer; p,qn,sig,un: single; u: glnar;

begin if (yp1> 0.9ge30) then begin

y2[lJ :=0.0; u[lJ :=0.0; end else begin

y2 [1 J : =-0.5; u [1 J : = (3.0/ (x (2 J -x ( 1 J ) ) * ( (y (2 J -y ( 1 J ) / (x (2 J -x ( 1 J ) -yp1) ;

end; for i:=2 to n-1 do begin

sig:=(x(iJ-x[i-1J)/(x(i+1J-x(i-1J); p:=sig*y2(i-1J+2.0; y2[iJ:=(sig-1.0)/p; u[iJ :=(y(i+1J-y[iJ )/(x[i+1J-x(iJ )-(y(iJ-y(i-1J )/(x(iJ-x(i-1J); u(iJ:=(6.0*u(iJ/(x(i+1J-x(i-1J)-sig*u(i-1J)/p;

end; if (ypn>0.9ge30) then begin

gn:=O.O; un:=O.O; end else begin

gn:=0.5; un:=(3.0/(x(nJ-x(n-1J))*(ypn-(y(nJ-y(n-lJ)/(x(nJ-x(n-1J))

end; y2(nJ:=(un-gn*u[n-1J)/(gn*y2(n-lJ+1.0); for k:=n-1 downto 1 do begin

y2(kJ:=y2(kJ*y2[k+1J+u(kJ; end;

end; procedure splint(xa,ya,y2a: glnar; n: glint; x: single; var y: single); var

klo,khi,k: integer; h,b,a: single;

begin klo:=l; khi:=n; while (khi-k1o>1) do begin

k:=(khi+klo) div 2; if (xa(kJ>x) then khi:=k else klo:=k;

end; h:=xa(khiJ-xa[kloJ; if (h=O.O) then begin

writeln('bad xa input'); readln; end;

Appendix D

63

a:=(xa[khij-x)/h; b:=(x-xa[kloj)/h; y:=a*ya[kloj+b*ya[khij+«a*a*a-a)*y2a[kloj+(b*b*b-b)*y2a[khij)*(h*h)/6.0;

end;

begin ndata:=4; fn:='czan.dat'; {Zangar geometry curve} assign(datafile,fn); reset(datafile); for i:=l to ndata do begin

readln(datafile,x[ij,y[ij)' {writeln(x[ij:9:2,y[ij:9:2);}

end; close(datafile); yp1: =1. Oe30; ypn: =1. Oe30; spline(yp1,ypn,ndata,y2); nda:=40; {number of points to be calculated} for i:=l to nda do begin

xx:=1.0*i/10.0; splint(x,y,y2,ndata,xx,yy); outp[ij :=yy;

end; Q:=19.0; {m3/day} H:=2.03; {m} hh:=1.14; {m} r:=O.025; {m} L:=(H*H-hh*hh)/(2.0*H); xx:=hh/r; 19x:=ln(xx)/ln(10.0); splint(x,y,y2,ndata,lgx,lgy); C:=exp(lgy*ln(10»; yy:=C; writeln(xx:9:2,' ',C:9:4); cond:=Q/(C*L*r); writeln('K= ',cond:9:2,' m/day'); writeln(lst,' r Q H hh L C K'); writeln(lst,r:7:3,' ',Q:7:2, I ',H:?:2,' ',hh:7:2,' ',L:7:2,'

C: 7 : 2 I' 1 I cond : 9 : 2 ) ; readln; 1: graphdriver:=detect; initgraph(graphdriver,graphmode, 'd:\tp'); line(10,O,10,250); line(10,250,510,250); i:=trunc(lO.O*ln(xx)/ln(lO»; xc:=10+trunc(50.0*(i/lO.O»; yc:=250-trunc«lO.O*outp[ij»; circle(xc,yc,4)i

color:=red; for i:=l to 40 do begin

xc:=10+trunc(50.0*(i/lO.0»; yc:=250-trunc«10.0*outp[ij»; putpixel(xc,yc,color);

end; color:=yellow; for i:=l to ndata do begin

xc:=10+trupc(50.0*x[ij); Yc:=250-trunc(10.O*(y[ij»; circle(xc,yc,l);

end; 2: readlni closegraph; end.

Appendix D

64

APPENDIX E PARTICLE SIZE ANALYSIS

Appendix E

Contents

page Sample master list (UB analysis) 1 _ 2

UB PSA results 3 _ 6

DWA analysis Shashe Wellfield boreholes PHl, PH2 and PH3 7

Soils Laboratory Sebele 8

Grain size distributions (GS Lobatse) 8

Appendix E

(i)

Sample master list for UB PSA analysis

number site sample date depth remark sample file PSA

1 1 1 25/4/97 0.05 tr1/0RC bag slt16 2 1 2 25/4/97 1. 25 tr1/0RC bag slt16 3 1 3 25/4/97 2.95 tr1/0RC bag slt16 4 1 4 25/4/97 3.80 tr1/0RC bag slt16 5 7 1 25/4/97 2.00 tr1/0RC bag slt16 6 7 2 25/4/97 2.75 tr1/0RC bag slt16 7 7 3 27/4/97 piez/ORC bag slt16 8 14 1 25/4/97 0.10 tr1/0RC bag slt16 9 14 2 25/4/97 0.90 tr1/0RC bag slt16

10 14 3 25/4/97 2.05 tr1/0RC bag slt16 11 14 4 25/4/97 3.00 tr1/0RC bag slt16 12 14 5 27/4/97 piez/ORC bag slt16 13 17 1 26/4/97 0.85 tr1/0RC bag slt16 14 17 2 26/4/97 2.15 tr1/0RC bag slt16 15 17 3 26/4/97 3.75 tr1/0RC bag slt16 16 1 1 28/4/97 0.05 isl/ORC bag slt16 17 1 2 28/4/97 0.25 isl/ORC bag s17t31 18 1 3 28/4/97 0.45 isl/ORC bag s17t31 19 1 4 28/4/97 2.35 isl/ORC bag s17t31 20 gap G1 01/07/96 0.00 beacon bag s17t31 21 gap G2 01/07/96 0.50 beacon bag s17t31 22 gap G3 01/07/96 1.40 beacon bag s17t31 23 gap G4 01/07/96 2.20 beacon bag s17t31 24 gap G5 01/07/96 3.00 beacon bag s17t31 25 gap G6 01/07/96 3.70 beacon bag s17t31 26 gap G7 01/07/96 4.20 beacon bag s17t31 27 gap G9 01/07/96 4.80 beacon bag s17t31 28 B1 B1 01/07/96 0.40 beacon bag s17t31 29 B2 B2 01/07/96 1.10 beacon bag s17t31 30 B3 B3 01/07/96 2.00 beacon bag s17t31 31 B4 B4 01/07/96 2.40 beacon bag s17t31 32 gap G8 01/07/96 4.70 beacon bag beac 33 3.2 01-MAR-94 1. 70 beacon ring beac 34 1.1 01-MAR-94 0.65 beacon ring beac 35 1.2 01-MAR-94 1.00 beacon ring beac 36 1.3 01-MAR-94 1. 33 beacon ring beac 37 1.4 01-MAR-94 2.32 beacon ring beac 38 3.1 01-MAR-94 0.65 beacon ring beac 39 repacked G8 01/07/96 4.70 beacon ring beac 40 3.6 01-MAR-94 0.39 beacon ring beac 41 3.7 01-MAR-94 0.70 beacon ring beac 42 4.1 01-MAR-94 0.91 beacon ring beac 43 4.3 01-MAR-94 1.68 beacon ring beac 44 4.12 01-MAR-94 0.18 beacon ring beac 45 4.14 01-MAR-94 0.79 beacon ring beac 46 4.16 01-MAR-94 1.19 beacon ring beac 47 4.20 01-MAR-94 2.00 beacon ring beac 48 5.1 01-MAR-94 0.30 beacon ring beac 49 5.3 01-MAR-94 0.66 beacon ring beac 50 5.5 01-MAR-94 0.97 beacon ring beac 51 5.7 01-MAR-94 1. 57 beacon ring beac 52 5.9 01-MAR-94 2.00 beacon ring beac 53 1 A1 28-JUN-97 1.03 ORC ring ringpsa 54 2 A2 28-JUN-97 1. 67 ORC ring ringpea 55 3 A3 28-JUN-97 2.11 ORC ring ringpsa 56 4 A4 28-JUN-97 2.73 ORC ring ringpsa 57 5 C2 30-JUN-97 1.02 ORC ring ringpsa 58 6 F1 04-JUL-97 1.15 ORC ring ringpea 59 7 F2 04-JUL-97 1. 83 ORC ring ringpsa 60 8 F3 04-JUL-97 2.65 ORC ring ringpea

Appendix E

1

number site sample date depth remark sample file PSA

61 9 F4 04-JUL-97 2.76 ORC ring ringpsa 62 10 Cl 30-JUN-97 0.93 ORC ring ringpsa 63 11 BC1 09-JUL-97 3.24 ORC ring ringpsa 64 12 BC2 09-JUL-97 4.13 ORC ring ringpsa 65 13 BC3 09-JUL-97 4.53 ORC ring ringpsa 66 14 G1 05-JUL-97 1. 70 ORC ring ringpsa 67 15 G2 05-JUL-97 2.74 ORC ring ringpsa 68 16 H1 06-JUL-97 1.40 ORC ring ringpsa 69 17 H2 06-JUL-97 2.20 ORC ring ringpsa 70 18 I1 06-JUL-97 2.40 ORC ring ringpsa 71 19 I2 06-JUL-97 4.13 ·ORC ring ringpsa 72 20 J1 06-JUL-97 1. 26 ORC ring ringpsa

Appendix E

2

Samples 1 - 16 Particle Size Analysis (1) dry sieving (2) fraction < 53/illl by Shimadzu centrifugal garticle size anal~er (SA-eP4, V1.01 .. Note these results are given as gercentages of the fraction <53/illl.

Slt16 T1.1 T1.2 T1.3 T1.4 T7.1 T7.2 T7.3 T14.1 T14.2 T14.3 T14.4 T14.5 T17.1 T17.2 T17.3 01.1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 2000 0.01 0.00 0.14 0.00 0.00 0.00 0.00 0.00 0.10 0.00 0.20 0.00 0.00 0.00 0.00 0.16 1000 0.29 0.52 1.92 0.16 0.06 0.02 0.00 0.25 0.51 0.45 2.07 0.02 0.33 0.05 0.02 1.26 500 6.15 11.35 13.12 3.47 1.36 0.37 0.28 4.06 17.33 5.21 9.17 2.17 21.42 0.49 0.46 16.87 355 19.38 23.20 32.58 17.25 5.35 2.32 1.00 12.06 26.59 14.38 26.52 15.90 26.00 1.48 2.16 38.27 250 24.93 23.84 43.75 52.00 16.16 17.92 10.62 26.38 40.61 39.58 71.53 71.35 45.62 16.07 28.44 55.93 180 18.67 16.39 16.62 35.42 27.43 44.31 41.16 29.16 39.70 55.51 53.23 53.02 55.60 59.76 119.75 58.52 106 24.49 20.79 11.13 13.79 63.19 52.51 81.40 33.04 36.52 53.47 24.18 23.67 50.28 136.09 98.34 72.67 53 7.46 5.57 2.68 1.70 7.90 2.67 7.65 5.62 5.76 5.14 2.47 2.32 6.77 15.13 3.09 22.00 <53 3.45 1.63 0.50 0.55 1.00 0.40 0.58 1.78 3.26 1.52 1.23 1.83 2.75 1.66 0.42 19.24 104.83 103.29 122.44 124.34 122.45 120.52 142.69 112.35 170.38 175.26 190.60. 170.28 208.77 230.73 252.68 284.92 % % % % % % % % % % % % % % % % 50

40 13.2 12.0 6.8 4.6 5.0 4.2 14.4 14.1 2.3 4.0 7.9 12.6 6.0 7.6 10.4 10.0 30 12.8 7.8 12.5 8.4 9.2 7.7 11.0 23.7 4.1 7.3 14.5 23.6 10.9 13.8 13.9 18.2 20 18.0 27.8 20.2 15.5 18.2 15.3 21.8 23.0 8.2 14.6 18.4 28.5 18.1 27.2 23.0 18.0 15 12.7 15.2 15.9 15.4 15.3 12.3 16.1 15.3 8.3 11. 1 17.5 13.4 17.8 14.4 14.5 12.3 10 18.3 18.6 17.8 21.0 21.7 20.3 16.8 13.9 13.6 18.0 19.3 11.8 20.6 17.0 17.5 13.8 w 8 8.4 6.6 7.4 9.8 10.2 9.2 6.7 4.9 9.6 9.2 7.6 3.6 8.6 6.4 6.8 6.2 6 7.6 3.9 9.7 10.4 9.4 11.8 5.5 3.3 12.0 10.1 6.2 2.6 8.5 6.3 6.3 6.6 5 0.0 1.4 0.5 1.7 0.5 1.6 0.4 0.0 1.6 2.0 0.7 0.0 0.1 0.0 0.7 2.4 4 0.0 1.3 0.0 1.5 0.5 1.6 0.4 0.0 2.7 2.4 0.7 0.0 0.2 0.0 0.7 2.2 3 2.9 2.6 3.6 4.0 2.9 4.2 1.9 1.4 4.9 3.4 2.0 0.8 2.5 2.4 1.7 3.8 2 2.4 1.3 2.2 3.5 2.6 4.6 1.7 0.1 8.4 4.9 2.0 1.3 2.4 1.9 1.4 3.7 0 3.7 1.5 3.4 4.2 4.5 7.2 3.3 0.3 24.3 13.0 3.2 1.8 4.3 3.0 3.1 2.8

100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Appendix E

Sanples 17 ~ 31 Particle Size Analysis C1L_d.ry_sieving (2) Jraction <53lUllPV Shimadzu centrifugal particle size analyzer (SA-CP4, V1.01l. Note these results are given as percentages of the fraction <53gm.

S17t31 01.2 01.3 01.4' Gl G2 G3 G4 G5 G6 G7 G9 Bl B2 B3 B4 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 2000 0.24 53.95 1.29 0.00 0.00 0.00 0.06 0.21 0.00 0.15 3.03 0.05 0.07 0.20 0.09 1000 1.21 10.53 2.86 0.31 0.40 0.61 0.92 2.39 0.24 1.22 6.98 0.62 0.31 0.60 0.54 500 12.69 20.41 17.17 8.03 5.76 7.93 8.64 11.65 2.53 17.34 20.91 8.00 7.70 10.58 7.86 355 21.94 21.04 29.95 33.27 19.80 24.26 27.44 44.03 22.98 74.83 50.70 25.85 21.61 37.09 19.31 250 31.79 36.07 39.98 50.67 37.16 48.42 60.54 118.49 116.74 54.00 46.23 39.05 38.67 62.64 34.80 180 33.13 39.20 44.46 26.42 31.57 46.62 54.00 55.66 61.09 14.54 29.78 27.52 34.96 44.99 25.36 106 34.29 39.02 53.09 20.08 35.40 57.40 22.06 20.84 17.44 16.21 26.05 44.86 61.47 56.50 45.49 53 9.60 13.05 16.57 3.48 7.24 11.19 1.19 2.88 1.12 2.52 3.75 17.17 22.87 11.31 19.06

<53 4.47 10.50 20.95 1.98 1.82 2.84 0.24 0.48 0.17 0.38 0.96 10.37 10.80 3.62 8.78 149.36 243.77 226.32 144.24 139.15 199.27 175.09 256.63 222.31 181.19 188.39 173.49 198.46 227.53 161.29

% % % % % % % % % % % % % % % 50 40 15.2 12.8 4.7 8.6 13.1 10.3 12.3 10.8 18.9 3.7 13.8 3.0 4.9 6.3 6.9 30 19.7 19.5 8.6 21.4 16.0 16.5 18.7 13.7 22.5 26.8 17.9 5.5 8.9 11.6 26.4 20 26.5 22.0 17.1 24.2 23.6 21.8 31.6 21.0 29.6 28.0 29.1 10.9 17.7 19.4 10.9 15 13.3 15.6 13.2 18.9 14.0 15.9 13.5 13.6 8.2 12.4 16.8 9.2 12.0 13.3 17.4 10 14.9 15.2 19.5 16.7 14.7 16.8 10.2 19.5 10.0 16.3 13.7 15.8 16.7 18.8 19.1

~ 8 4.3 5.7 10.0 3.3 5.0 6.0 3.9 7.4 3.3 4.4 3.1 9.8 8.7 7.1 6.8 6 2.8 5.1 10.6 3.5 4.9 5.2 3.9 6.5 2.7 3.5 2.3 12.0 9.9 7.9 6.4 5 0.4 0.3 2.6 0.0 1.0 0.8 0.4 1.3 0.6 0.4 0.3 3.0 3.3 1.9 0.8 4 0.4 0.2 2.3 0.0 0.9 0.7 0.3 1.2 0.6 0.3 0.2 2.6 3.0 1.7 0.6 3 1.0 1.6 5.3 1.3 2.5 2.3 1.8 2.1 1.0 1.8 1.0 7.7 5.9 3.7 2.6 2 0.8 1.1 3.8 0.7 2.4 2.2 2.4 1.7 1.3 1.6 1.0 8.6 5.5 3.8 1.5 o 0.7 0.9 2.3 1.4 1.9 1.5 1.0 1.2 1.3 0.8 0.8 11.9 3.5 4.5 0.6

100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Appendix E

S!!!!!lles 32 . 52 Particle Size Anal~sis ~1} drt sieving ~2} fraction <53~ b~ Shimadzu centrifugal ~rticte size anal~zer SSA-CP4 1 V1.01}. Note these results are given as percentages of the fraction <53gm.

repack: 3.2 1.1 1.2 1.3 1.4 3.1 repack 3.6 3.7 4.1 4.3 4.12 4.14 4.16 4.20 5.1 5.3 5.5 5.7 5.9 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 2000 0.25 0.03 0.00 0.00 0.00 0.05 0.00 0.25 0.00 0.00 0.00 0.17 0.03 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0 1000 6.84 0.22 0.47 0.64 0.61 0.72 0.25 6.52 0.34 0.29 0.20 0.71 0.29 0.19 0.23 0.45 0.38 0.44 0.31 0.21 0.2 500 43.52 2.26 7.14 7.44 6.27 6.63 6.74 41.07 6.06 5.28 4.68 4.76 4.55 4.57 4.43 4.69 6.89 6.04 5.03 2.56 3.03 355 81.19 9.08 26.09 24.77 21.70 21.50 12.99 77.13 20.30 17.30 19.95 11.60 18.96 20.78 16.97 9.81 24.54 22.13 20.25 10.23 13.07 250 29.68 26.68 48.61 45.04 40.56 53.85 '31.02 28.70 40.62 37.11 35.37 21.43 36.60 38.05 31.82 16.96 46.72 43.16 42.08 27.46 38.83 180 13.16 34.01 35.76 34.26 33.52 47.25 35.81 12.08 39.92 39.43 28.35 21.32 27.95 26.12 26.24 18.81 39.80 39.29 40.22 39.15 48.36 106 17.33 77.16 39.22 40.38 49.04 23.53 63.22 16.60 50.62 58.80 64.38 76.43 58.16 55.63 66.83 81.78 39.42 41.58 46.00 64.84 49.85 53 2.19 12.18 8.30 9.01 12.39 1.58 12.24 1.94 7.72 9.74 16.93 23.74 17.49 15.17 17.87 24.77 8.63 9.15 10.39 15.23 8.41

<53 0.29 1.64 2.10 2.92 3.74 0.37 2.80 0.07 2.55 2.86 2.46 3.66 2.19 2.64 2.45 3.87 4.48 5.71 5.69 4.07 1.65 194.45 163.26 167.69 164.46 167.83 155.48 165.07 184.36 168.13 170.81 172.32 163.82 166.22 163.21 166.84 161.14 170.86 167.50 169.97163.75 163.40

% % % % % % % % % % % % % % % % % % % % % 50 40 7.4 2.8 11. 1 11.4 2.9 8.2 7.0 9.9 7.0 9.1 14.3 13.2 14.'1 14.0 0.0 9.4 9.7 5.1 15.3 8.9 11.7 30 13.6 5.2 17.0 13.4 5.4 15.0 12.8 17.4 12.9 13.6 21.6 11.4 18.1 11.8 14.2 12.0 16.9 9.3 13.4 15.4 11.5 20 21.7 10.3 18.5 21.0 10.7 19.8 20.9 25.0 23.7 21.3 22.8 24.9 22.0 23.4 41.2 23.3 18.4 16.1 22.5 21.6 22.4 15 15.5 13.5 17.8 14.9 8.6 14.3 15.7 16.7 17.4 16.2 15.8 14.9 14.7 16.2 18.3 15.8 14.1 12.4 12.3 12.9 13.8 10 15.4 27.5 17.2 18.1 17.9 16.2 18.9 14.1 18.8 20.5 13.8 18.1 17.5 17.5 13.1 19.0 17.2 19.0 16.4 18.4 18.8 8 6.1 12.6 6.6 7.4 10.6 7.7 8.9 9.0 7.2 7.6 5.0 6.2 5.7 6.3 4.7 7.0 7.5 10.3 6.9 7.7 7.5

V> 6 7.5 11.8 5.7 6.6 15.0 8.5 7.1 3.9 5.8 5.8 4.0 5.3 4.0 4.7 4.5 5.6 7.2 11.2 6.0 3.6 7.0 5 4.0 1.4 0.8 1.4 0.3 2.0 0.8 0.0 0.6 0.7 0.1 0.8 0.0 0.0 0.1 1.0 1.5 2.7 0.6 2.2 1.2 4 3.9 1.3 0.8 1.4 0.3 1.8 0.8 0.0 0.8 0.7 0.1 0.7 0.0 0.1 0.2 0.8 1.4 2.6 0.4 2.1 1.1 3 2.0 4.5 1.9 2.1 9.7 3.4 2.2 2.3 1.5 1.6 1.5 2.1 1.3 0.9 1.4 2.5 2.8 5.1 2.6 2.8 2.5 2 1.4 4.0 1.4 1.3 9.8 2.0 1.7 0.2 1.3 1.2 0.4 1.4 1.4 0.4 0.6 2.0 1.8 3.8 2.1 2.3 1.6 0 1.5 5.1 1.2 1.0 8.8 1.1 3.2 1.5 3.0 1.7 0.6 1.0 1.2 4.7 1.7 1.6 1.5 2.4 1.5 2.1 0.9

100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100

Appendix E

Samples 53 - 72 Particle Size Analysis (1) dry sieving (2) fraction <53#ffi by Shimadzu centrifugal particle size analyzer (SA-CP4, V1,01), Note these results are given as percentages of the fraction <53gm.

A1 A2 A3 A4 c2 F1 F2 F3 F4 C1 BC1 BC2 BC3 G1 G2 H1 H2 11 12 J1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9

2000 0.04 0.01 0.05 0.00 0.00 0.00 0.15 0.21 0.08 0.00 0.45 0.02 0,29 0.11 0.00 0.00 0.02 0.01 0.01 0.01 1000 0.32 0.20 0.10 0.08 0.04 0.30 0.83 1.28 1.15 0.11 4.74 1.70 2:75 0.68 0.09 0.28 0.51 0.45 0.34 0.66 500 2.97 1.93 0.84 0.47 0.66 4.38 6.54 8.75 8.26 2.12 18.53 21.02 20.03 10,27 1.27 2.80 10.03 4.97 9.64 6.72 355 9.63 6.50 3.10 2.34 2.87 15.08 18.16 23.17 23.32 8.24 37.60 71.28 62.56 25.06 10.21 8.86 23.05 16.23 27.11 18.81 250 24.78 18.54 11.68 17.79 15.06 26.58 39.15 44.06 44.40 29.39 62.50 49.38 40.63 42.07 61.57 26.90 41.30 35.44 39.54 35.31 180 38.72 36.63 32.10 64.04 54.62 21.32 40.45 40.08 39.38 64.43 30.71 8.23 15.17 36.97 59.48 52.99 48.10 39.25 31.21 32.82 106 71.02 79.88 96.10 65.71 69.45 21.24 44.96 38.09 38.73 58.91 12.99 7.55 12.78 46.70 26.81 66.59 38.04 49.56 27.90 45.55 53 8.54 9.18 11.15 4.43 9.71 5.37 11.06 8.60 8.92 10.81 0.95 2.15 1.95 12.78 3.60 11.72 9.35 14.47 9.54 15.82

<53 1.79 1.87 1.28 0.61 3.73 3.73 4.48 3.24 3.35 7.15 0.16 0.26 0.36 4.83 0.92 2.99 5.21 5.40 5.58 3.95 157.81 154.74 156.40 155.47 156.14 98.00165.78167.48167.59181.16168.63161.59156.52 179.47163.95 173.13175.61 165.78150.87159.65

% % % % % % % % % % % % % % % % % % % % 50 40 10.1 4.1 9.6 5.6 4.4 5.6 2.4 9.9 7.9 7.1 8.6 8.0 10.7 4.6 7.6 3.4 4.2 4.2 9.1 15.3 30 13.3 7.4 11.2 10.2 8.1 10.2 4.4 13.8 14.5 13.1 15.7 13.5 16.8 8.4 14.0 6.2 7.7 7.7 16.0 13.4 20 19.9 20.2 21.1 18.8 16.2 18.6 8.8 16.4 20.3 20.9 20.3 21.7 24.4 16.7 20.8 12.3 15.4 15.3 24.9 22.5 15 14.6 20.0 15.6 17.5 12.0 13.0 9.3 14.9 13.6 14.7 14.8 13.9 15.4 13.8 13.2 14.8 12.8 15.5 15.6 12.3 10 20.4 25.5 20.1 26.4 17.5 19.0 26.3 19.0 19.2 19.7 18.3 19.4 16.7 23.0 19.9 26.9 19.6 22.7 18.1 16.4 8 7.6 9.7 8.5 8.6 10.5 9.7 14.2 7.6 8.2 8.7 7.5 7.5 5.6 10.7 7.0 11.7 10.4 10.2 6.7 6.9

~ 6 6.9 7.7 6.8 8.2 11.2 9.3 15.4 8.2 8.0 7.6 6.9 7.0 4.4 10.5 7.8 10.5 11.9 9.8 5.1 6.0 5 1.2 0.0 1.2 0.3 2.7 2.4 1.3 1.8 1.5 0.7 0.9 1.4 0.8 1.0 0.8 1.2 1.8 2.0 0.8 0.6 4 1.1 0.0 1.1 0.1 2.4 2.2 1.1 1.6 1.3 0.7 0.8 1.3 0.7 0.9 0.7 0.9 1.7 1.8 0.7 0.4 3 2.4 3.3 2.5 3.1 5.9 4.2 8.0 3.8 3.6 2.5 2.6 2.7 1.8 3.3 2.6 4.0 3.9 4.6 1.5 2.6 2 1.7 1.7 1.5 0.7 4.8 3.4 7.2 2.4 1.5 1.9 1.8 2.0 1.5 3.0 2.3 3.3 4.1 4.2 1.0 2.1 o 0.5 0.4 0.7 0.4 4.3 2.4 1.5 0.5 0.5 2.2 1.9 1.7 1.1 4.1 3.0 5.0 6.5 2.0 0.5 1.5

99.7 100 99.9 99.9 100 100 99.9 99.9 100.1 99.8 100.1 100.1 99.9 100 99.7 100.2 100 100 100 100

Appendix E

Results of DWA grain size analxsis boreholes PHI, PH2, PH3. (Data rej20rt on Shashe Maun Pilot Borehole Construction Rej20rt

OWAPHl depth(m) 1000 850 500 355 250 180 125 65 <65 totwt

1 0.10 0.20 0.90 3.50 12.40 51.00 58.40 21.70 1.30 149.50 2 0.20 0.10 1.90 5.90 13.20 27.60 35.70 11.40 0.70 96.70 3 1.60 0.30 2.10 6.60 28.00 74.80 42.20 2.10 0.40 158.10 4 2.60 1.10 6.60 22.10 42.90 53.10 173.00 6.30 0.30 308.00 5 1.50 0.90 11.10 59.90 63.80 18.40 14.20 2.40 0.20 172.40 6 1.10 0.60 4.40 20.00 52.30 61.70 29.80 10.50 3.20 183.60 7 2.80 2.30 22.10 59.00 52.40 39.40 27.80 13.10 4.40 223.30 8 2.10 1.60 22.40 55.60 32.60 6.10 16.00 12.10 1.90 150.40 9 1.80 1.60 24.80 69.90 43.40 22.80 16.20 9.40 2.30 192.20

10 0.80 0.70 6.70 26.10 72.20 44.60 9.70 1.90 1.50 164.20 11 1. 70 1.20 8.90 29.00 61.00 42.40 18.60 8.10 6.10 177.00 12 2.30 0.60 3.20 9.50 19.50 44.40 48.60 21.00 14.80 163.90 13 4.50 1.50 8.10 17.20 30.70 65.30 54.20 13.20 1.70 196.40 14 2.30 0.90 5.00 13.80 27.90 40.30 38.10 10.00 2.00 140.30 15 3.30 0.80 7.00 18.40 33.40 36.20 25.20 6.30 1.40 132.00 16 4.60 0.80 4.90 14.40 30.20 57.60 40.10 16.20 7.00 175.80

OWAPH2 depth(m) 1000 850 500 355 250 180 125 65 <65 totwt

1 0.90 0.80 8.60 19.90 27.50 42.40 39.40 9.60 5.00 154.10 2 2.00 1.00 5.90 14.70 37.70 72.70 26.90 14.00 4.30 179.20 3 0.20 0.30 3.80 14.10 50.10 92.80 26.10 8.80 0.70 196.90 4 0.60 0.00 6.90 20.00 46.40 65.30 21.60 5.80 0.40 167.00 5 3.20 2.10 21.80 52.30 42.50 56.60 26.00 5.00 0.40 209.90 6 1.60 1.60 21.80 49.90 39.00 50.10 26.40 9.10 1.10 200.60 7 1.90 1.20 12.10 37.80 66.80 46.90 25.70 8.60 0.90 201.90 8 0.90 0.70 56.00 24.20 76.30 48.40 16.90 8.60 1.00 233.00 9 0.40 0.20 1.10 8.40 65.90 97.30 16.00 5.80 0.70 195.80

10 0.30 0.20 1.40 7.60 57.10 94.90 17.70 3.80 0.60 183.60 11 0.20 0.10 1.10 6.30 52.00 117.70 21.00 3.10 0.20 201.70 12 0.20 0.10 1.20 7.30 77.40 109.60 14.90 2.90 0.40 214.00 13 0.20 0.10 0.80 5.30 57.60 101.60 13.90 2.20 0.40 182.10 14 0.20 0.10 0.70 5.50 52.60 113.00 13.60 1.20 0.20 187.10 15 0.30 0.30 4.80 20.70 58.80 63.70 21.90 5.70 2.30 178.50 16 2.30 1.80 7.70 23.90 42.10 38.90 31.00 11 . 10 8.60 167.40

OWAPH3 depth(m) 1000 850 500 355 250 180 125 65 <65 totwt

1 0.80 0.40 3.00 9.10 20.90 70.10 67.00 25.10 4.2 200.6 2 0.80 0.80 2.30 6.10 15.20 53.50 75.80 33.40 2.5 190.4 3 0.90 0.80 1. 70 6.70 36.90 76.70 37.10 13.60 1.10 175.5 4 0.70 0.60 1.10 6.40 65.70 108.70 22.60 6.40 1.00 213.2 5 0.70 0.60 2.30 19.50 82.90 49.10 10.10 3.50 0.70 169.4 6 1.10 1.00 7.70 39.00 69.50 72.60 23.80 5.60 0.90 221.2 7 0.20 0.10 1.20 8.80 50.20 94.80 23.50 5.30 1.10 185.2 8 0.40 0.30 1. 70 9.20 41 .10 92.00 29.00 8.30 1.90 183.9 9 1.40 1.00 11.90 37.70 62.20 82.10 21.70 2.60 0.40 221

10 1.80 1.70 15.30 37.80 62.60 78.10 18.50 7.00 0.30 223.1 11 2.60 2.49 2.49 51.40 34.10 53.80 15.20 6.10 0.7 168.88 12 1.90 2.20 46.80 88.40 27.80 25.80 10.50 3.60 0.00 207 13 3.20 2.80 56.80 113.00 22.70 23.10 6.60 1.50 0.3 230

Appendix E

7

Particle size analysis by Soils Lab of the Ministry of Agriculture (Sebele)

salri' PHh20 PHca EC P orgC CEC Ca M9 K Ha PBS carbo

8 5.45 5.15 O.OB OB 1.2 6.3 2.1 0.1 0.1 0.0 37 3.0 10 6.85 6.32 O.OB 1A 0.1 3.9 0.7 0.3 0.0 0.0 26 0.0 25 6.29 6.00 O.OB 1A 0.0 1.7 0.1 0.1 0.0 0.0 12 3.0 30 5.49 4.71 O.OB 2B 0.2 4.1 0.7 0.1 0.0 0.0 20 1.0 32 6.13 5.84 O.OB 0.0 4.1 0.1 0.1 0.0 0.0 5 5.0

vcs cs rns Is vis cs; samp labno 1000 500 250 106 53 <53 fsi clay

% % % % % % % % 8 198 0.2 2.4 29.5 54.9 5.6 0.2 4.7 2.5 100

10 199 0.4 1.9 27.5 63.9 2.8 0.1 3.4 0.0 100 25 200 0.5 1.4 56.9 39.6 0.5 0.0 1 .1 0.0 100 30 201 0.4 4.5 42.4 43.3 6.0 0.0 3.4 0.0 100 32 202 2.0 19.8 57.7 18.9 1.1 0.1 0.4 0.0 100

PHca pH caCIZ p phosphorus PBS % base saturation carbo carbonates clay hydrometer anaLysis fsi calculated as remainder (lost siLt)

Particle Size Analysis by Geological Survey Lobatse (dry sieving)

sampl i ng date 29·JUH·9709·JUL·97 (pLastic bags)

sarrple depth <63 63 125 250 500 1000 2000 mum

(rn) % % % % % % % A1 0.98 0.9 11.2 63.4 22.1 2.1 0.3 0.0 A2 1.19 1.2 11.0 61.4 24.1 2.0 0.3 0.0 A3 1.59 0.8 11 .2 67.5 18.7 1.6 0.2 0.0 A4 2.01 0.6 9.8 71.3 17.4 0.8 0.1 0.0 AS 2.63 0.4 7.1 75.1 17.0 0.3 0.1 0.0 A6 3.50 0.1 2.4 54.6 41.9 0.9 0.1 0.0 C1 0.72 1.8 8.3 57.0 28.6 4.1 0.2 0.0 C2 1.02 2.2 9.1 58.8 27.4 1.9 0.6 0.0 C3 1.64 0.8 6.3 63.1 29.0 0.2 0.6 0.0 C4 3.70 0.9 8.7 61.0 28.6 0.6 0.2 0.0 F1 0.64 3.2 10.0 45.0 37.9 3.6 0.3 0.0 F2 1 . 16 3.2 9.0 40.3 43.0 4.3 0.2 0.0 F3 1.83 1.7 9.2 48.6 36.2 3.7 0.5 0.1 F4 2.65 2.6 9.4 44.6 38.5 4.4 0.5 0.0 F5 3.30 2.1 9.2 44.9 38.2 4.8 0.8 0.0 F6 3.76 1.7 7.3 39.3 45.4 5.8 0.5 0.0 F7 5.10 1 .1 7.1 41.9 43.6 5.3 0.9 0.1 G1 1.53 1.3 9.0 37.7 39.8 11.7 0.5 0.0 G2 2.74 0.2 1.7 28.5 64.8 4.3 0.5 0.0 G3 3.25 0.5 3.3 62.8 29.8 2.2 1.4 0.0 H1 0.67 1.8 6.2 40.3 35.7 11.9 4.1 0.0 H2 1.40 0.5 4.6 43.0 41.4 9.6 0.9 0.0 H3 2.20 4.4 7.5 40.9 31.8 12.8 2.6 0.0 H4 2.73 3.9 8.3 37.4 30.9 13.4 6.1 0.0 11 1.75 2.8 13.9 54.4 26.3 2.2 0.3 0.1 12 3.71 2.3 7.3 37.9 38.3 13.6 0.6 0.0 13 4.13 4.1 7.9 34.4 38.3 12.0 3.3 0.0 J1 1.20 2.4 13.6 41.0 38.1 4.6 0.3 0.0 J2 2.50 1.8 12.6 46.9 33.1 4.4 1 .2 0.0

Appendix E

8

APPENDIX F POROSITY, BULK DENSITY AND HYDRAULIC CONDUCTIVITY

Results ring analysis porosity, bulk density and hydraulic conductivity (permeameter)

number site sample date depth poras i ty bulk k err method masterlist % g/cm3 m/day m/day number

33 beacon 3.2 01·MAR·94 1. 70 35.53 1.63 4.85 0.39 7 consthd 34 beacon 1.101·MAR·94 0.65 30.12 1.68 4.77 0.45 3 consthd

35 beacon 1.2 01'MAR-94 1.00 32.71 1.65 5.50 0.53 2 consthd 36 beacon 1.3 01·MAR·94 1.33 32.35 1.68 3.87 0.31 2 consthd 37 beacon 1.4 01·MAR·94 2.32 31.35 1.69 20.24 1.33 3 consthd 38 beacon 3.1 01·MAR·94 0.65 34.41 1.62 0.83 0.54 3 consthd 39 beacon S3201·MAR·94 4.70 30.18 1.85 19.18 1.01 6 consthd 40 beacon 3.6 01·MAR·94 0.39 34.95 1.69 0.0044 1 faLhead

41 beacon 3.7 01'MAR-94 0.70 36.53 1.72 0.0010 1 faLhead 42 beacon 4.101·MAR·94 0.91 30.99 1.73 2.47 0.04 2 consthd 43 beacon 4.3 01·MAR·94 1.68 34.69 1.65 2.44 0.02 2 consthd 44 beacon 4.1201·MAR·94 0.18 35.76 1.67 7.89 0.17 3 consthd 45 beacon 4.14 01'MAR-94 0.79 32.82 1.64 3.86 0.08 2 consthd 46 beacon 4.16 01·MAR·94 1.19 32.28 1.72 2.85 0.01 2 consthd 47 beacon 4.20 01·MAR·94 2.00 35.31 1.62 3.17 0.08 2 consthd 48 beacon 5.101·MAR·94 0.30 30.28 1. 71 3.34 0.10 2 consthd 49 beacon 5.3 01·MAR·94 0.66 30.31 1.68 3.46 0.16 2 consthd 50 beacon 5.5 01·MAR·94 0.97 28.75 1.71 1.21 0.02 2 consthd 51 beacon 5.701·MAR·94 1.57 34.21 1.65 3.64 0.00 2 consthd 52 beacon 5.9 01·MAR·94 2.00 36.48 1.64 12.70 0.44 4 consthd 53 ORC Al 28·JUN·97 1.03 35.25 1.58 7.15 0.05 2 consthd 54 ORC A2 28· JUN ·97 1.67 36.45 1. 55 7.59 0.07 2 cansthd 55 ORC A3 28· JUN ·97 2.11 38.35 1.57 8.64 0.10 2 consthd 56 ORC A4 28·JUN·97 2.73 35.87 1.56 6.57 0.21 2 consthd 57 ORC C2 30·JUN·97 1.02 32.05 1.62 2.98 0.05 2 consthd 58 ORC Fl 04·JUL·97 1.15 33.25 1.66 5.71 0.14 2 consthd 59 ORC F2 04·JUL·97 1.83 33.82 1.68 6.18 0.07 2 consthd 60 ORC F3 04·JUL·97 2.65 32.08 1.68 10.87 0.06 2 consthd 61 ORC F4 04·JUL·97 2.76 25.85 1.85 7.71 0.04 2 consthd 62 ORC Cl 30'JUN-97 0.93 30.88 1.57 notposs 63 ORC BCl 09-JUL-97 3.24 32.70 1.69 21.43 0.19 4 consthd 64 ORC BC2 09-JUL-97 4.13 32.60 1.62 35.41 0.47 4 consthd 65 ORC BC3 09-JUL-97 4.53 30.86 1.57 30.14 0.10 4 consthd 66 ORC Gl 05-JUL'97 1.70 33.07 1.80 0.49 0.05 5 faLhead

67 ORC G2 05-JUL'97 2.74 34.52 1.64 10.35 0.95 2 consthd 68 ORC Hl 06-JUL-97 1.40 35.05 1. 74 1.95 0.01 2 consthd 69 ORC H2 06'JUL-97 2.20 32'.99 1. 76 0.25 0.06 5 faLhead 70 ORC 11 06-JUL-97 2.40 35.96 1.67 3.26 0.20 2 consthd 71 ORC 12 06-JUL-97 4.13 28.51 1.58 0.020 0.005 6 falhead 72 ORC Jl 06-JUL-97 1.26 29.07 1.60 3.48 0.02 2 consthd

avg 32.98 1.66 standdev 2.64 0.07

Appendix F

1

APPENDIX G HYDROCHEMISTRY

Appendix G

Contents

Hydrochemical analysis GS laboratory

Ionic balances GS analysis

Ionic balances GS anion, UB cation analysis

Appendix G

(i)

page

1

2

4

....

>­"t:l "t:l §l 0-X Q

Data from DGS-Chemical laboratory in m~" lab piez.lriver date EC pHDS

le samEled {uS/cm! 17/454 A 29-06-97 195 6.22 150

w/97/456 C 01-07-97 155 5.97 130 w/97/450 G 05-07-97 132 6.29 88 w/97/455 J 07-07-97 145 6.12 120 w/97/452 F 04-07-97 125 6.21 130 w/97!541 RWl 02-07-97 112 6.63 70 w/97/453 RG2 02-07-97 119 6.56 78

field data plez.lriver temp EC pH Alk.

(oC) (uS/cm) (mgn) fS:- ----z;E-·~·--6"llll____,_zs:\

C 23.5 164 6.5 G 24.9 142 6 J 21 155 7 F 25.5 130 6 61

RWl 14.5 121 6 46.8 RG2 15 118 6

C03 HC03

0 93 0 64 0 66 0 55 0 44 0 49

F Cl Br S04 P04

0.Q7 4.1 <0.5 0 <0.5 <0.05 7.0 <0.5 0 <0.5 0.06 4.1 <0.5 0 <0.5

<0.05 8.0 <0.5 0 <0.5 0.08 8.2 <0.5 0 <0.5 0.07 6.9 <0.5 0 <0.5

Data from UB-Chemical laboratory in mgll

N03

<0.5 <0.5 5.8

<0.5 <0.5 <0.5

plez. Na ~M!J -C.------zn -';:-9:4 -74 -4.95 . 1.080:036 C 10.1 6.4 3.46 6.17 0.041 G 8.1 11.4 2.18 3.38 0.051 J 10.2 13.8 2.73 4.25 0.034 F 8 10.6 1.37 2.46 0.026

RWl 7.9 7.6 2.67 3.51 0.094 RG2 8.1 10.2 1.91 2.69 0.014

RW1 and RG2 is surface water collected near the weir and gauge respectively

N02 SI02 Na K Mg Ca

<0.3 55 8 6.1 4 18 <:0.3 22 7 11 3 9 <0.3 45 9 14 3 5 <0.3 64 7 10 2 8 <0,3 22 7 8.8 2 7 <0.3 22 7 8 2 8

Ionic balances using cations and anions data from DGS-Chemical laboratory

electrical fonnula neutrality

Plez. A Na ('11) wei~t Charge (meqll) (%)

1 0 K 7.2 39.1 1 0.18414322

Mg 5 24.3 2 0.41152263 Ca 19 40 2 0.95

1.8919862 -ll.4 HC03 99 61 1.62295082

F 0.15 19 0.00789474 Cl 6.9 35.5 0.1943662

N03 5.2 62 0.08387097 1.90908272

Piez. C Na 8 23.1 1 0.34632035 K 6.1 39.1 1 0.15601023

Mg 4 24.3 2 0.32921811 Ca 18 40 2 0.9

1.73164868 2.6 HC03 93 61 1.52459016

F 0.D7 19 0.00368421 Cl 4.1 35.5 0.11549296

N03 62 0 1.64376733

Piez. G Na 7 23.1 1 0.3030303 K 10.8 39.1 1 0.27621483

Mg 3 24.3 2 0.24891358 Ca 9 40 2 0.45

1.27615872 1.2 HC03 84 61 1.04918033

F 19 0 Cl 7 35.5 0.1971831

N03 62 0 1.24636343

Piez. J Na 9 23.1 1 0.38961039 K 13.6 39.1 1 0.34782609

Mg 3 24.3 2 0.24891358 Ca 5 40 2 0.25

1.23436006 -2.4 HC03 66 61 1.08196721

F 0.08 19 0.00315789 Cl 4.1 35.5 0.11549296

N03 5.8 62 0.09354839 1.29416645

Piez. F Na 7 23.1 1 0.3030303 K 10 39.1 1 0.25575448

Mg 2 24.3 2 0.16480905 Ca 8 40 2 0.4

1.12339383 -ll.2 HC03 55 61 0.90163934

F 19 0 Cl 8 35.5 0.22535211

N03 62 0 1.12699146

Appendix G

2

Ionic balances using cations and anions data from DGS·-Cl1emical laboratory

electr~cal

formula neutramy

K 8.8 39.1 1 0.22506394 Mg 2 24.3 2 0.16460905 Ca 7 40 2 0.35

1.0427033 4.3 HC03 44 61 . 0.72131148

F 0.08 19 0.00421053 Cl 8.2 35.5 0.23098592

N03 62 0 0.95650792

RG2 Na l 23.1 '1 0.3030303 K 8 39.1 1 0.20480358

Mg 2 24.3 2 0.16480905 Ca 8 40 2 0.4

1.072242iM 3.4 HC03 49 61 0.80327869

F 0.07 19 0.00368421 Cl 6.9 35.5 0.1943662

N03 62 0 1.0013291

RW1 and RG2 sutiace water near the weir and near the gauge respectively

Appendix G

3

Ionic balances using cations data from UB-Chemistry lab and anions data from OGS-chem. lab

formula electrical weight neutrality

(mg/l) charge (meg/l) (%) Piez. A Na 9.4 23.1 1 0.40692641

K 7.4 39.1 1 0.18925831 Mg 4.95 24.3 2 0.40740741 Ca 1.08 40 2 0.054

sum of cations 1.05759213 -29 HC03 99 61 1.62295062

F 0.15 19 0.00789474 Cl 6.9 35.5 0.1943662

N03 5.2 62 0.08387097 sum of anions 1.90908272

Piez. C Na 10.1 23.1 1 0.43722944 K 6.4 39.1 1 0.16368286

Mg 3.46 24.3 2 0.28477366 Ca 6.17 40 2 0.3085

sum of cations 1.19418696 -16 HC03 93 61 1.52459016

F 0.Q7 19 0.00368421 Cl 4.1 35.5 0.11549296

N03 62 0 sum of anions 1.64376733

Piez. G Na 8.1 23.1 0.35064935 K 11.4 39.1 1 0.2915601

Mg 2.18 24.3 2 0.17942387 Ca 3.36 40 2 0.169

sum of cations 0.99063332 -11 HC03 64 61 1.04918033

F 19 0 Cl 7 35.5 0.1971831

N03 62 0 sum of anions 1.24636343

Piez. J Na 10.2 23.1 1 0.44155844 K 13.8 39.1 1 0.35294118

Mg 2.73 24.3 2 0.22469136 Ca 4.25 40 2 0.2125

sum of cations 1.23169098 -2 HC03 66 61 1.08196721

F 0.06 19 0.00315789 Cl 4.1 35.5 0.11549296

N03 5.8 62 0.09354839 sum of anions 1.29416646

Piez. F Na 8 23.1 0.34632035 K 10.6 39.1 1 0.27109974

Mg 1.37 24.3 2 0.1127572 Ca 2.46 40 2 0.123

sum of cations 0.85317729 -14 HC03 55 61 0.90163934

F 19 0 Cl 8 35.5 0.22535211

N03 62 0 sum of anions 1.12699146

Appendix G

4

Ionic balances lab and

weight neutrality (mg/l) charge (meg/l) (%)

RW1 Na 7.9 23.1 1 0.34199134 K 7.6 39.1 1 0.1943734

Mg 2.67 24.3 2 0.21975309 Ca 3.51 40 2 0.1755

sum of cations 0.93161783 ·1 HC03 44 61 0.72131148

F 0.08 19 0.00421053 Cl 8.2 35.5 0.23098592

N03 62 0

sum of anions 0.95650792

RG2 Na 8.1 23.1 0.35064935

K 10.2 39.1 1 0.26086957

Mg 1.91 24.3 2 0.15720165

Ca 2.69 40 2 0.1345

sum of cations 0.90322056 -5

HC03 49 61 0.80327869

F 0.Q7 19 0.00386421

Cl 6.9 35.5 0.1943862

N03 62 0

sum of anions 1.0013291

Appendix G

5

APPENDIX H COMPUTATIONAL NOTE ON FLOW TO A WELL IN A WATER. TABLE AQUIFER I

Appendix H

FLOW TO A WELL IN A WATER-TABLE AQUIFER: SPEEDING UP THE COMPUTATION OF TYPE CURVES FOR LOW BETA VALVES

A. Gieske, GeolollY Dept, University of Botswana, P /Ba!: 0022, Gaborone, Botswana

Abstract

A study is made of the computer implementation of the recently developed Laplace Transform Solution (Moench, 1996) for flow to a well in a water-table aquifer, Some suggestions are made to improve the speed of computation, especially for low beta values. The most important suggestion is to calculate the type curves at points which are spaced a factor 2 apart which allows more efficient use of the Stehfest inversion algorithm.

Introduction

Small scale exploratory pumping tests in shallow unconfined aquifers of the Okavango Delta, Botswana, were conducted recently. Because the study area was actually inside a game reserve, and not easily accessible, lightweight equipment had to be used and piezometers (50 mm diameter) were inserted manually. Water was pumped through a small submersible pump (Grundfos MP-I). A typical piezometer-pumping well configuration is shown in Fig.1. Well C was pumped at a rate of 16 m3 dol for 5 hours. The test was then analyzed according to the method described by Moench (1996), using the commercial package Aquifer Test (1997). Although the results were satisfacory, it took the programme quite long (54 seconds) on a 486DX (33 MHz) to produce the plot with the two type curves (Fig. 4). This prompted me to re-analyze the solution by Moench (1996) and to try to make its implementation faster. Some improvements are suggested in this short note.

Moench's Laplace transform solution, assuming the pumped well is a line source (Moench, 1996) is given by

2 i: Ko(x,~sin[. ,(l-d"ll-sin[ e ,(1-i~l][sin( e ,zD2) -sinCe "zD1)]

p(iD-d"l(zD2-zD}) .-0 e ,[O.5e n +0.25sm(2e.ll (1)

where Ko is the modified Bessel function of the second kind and order zero, Ku = [ B En

2 + P J'" and En are the roots of

• ,Ian(e.l p (2)

(op+p/y)

The non-dimensionalized variables are summarized in Table 1. Refer to Moench (1996) for further explanation.

1

For the pumping test !illustrated in Fig. 1, B values ranged from l.Ox10-3 (piezometer E) to 4.4x10-3 (piezometer D). The low values of B are the reason for the long calculation times, because the lower the B values, the more terms in (1) need to be evaluated to ensure sufficient qonvergence of the series.

Equation (1) is th~n inverted by use of the Stehfest (1970) algorithm. Moench (1996) calculates 32 points per type curve, 4 equally spaced poirits per decade on a logarithmic scale (see Fig. 2).

Analysis

The relevant computatidnal elements are

A. The Stehfest (1970) inversion formula is given by

h(t) = 1n2 f v, -d In2 i) t ,~t " t

(3)

where the Vi are fixed numbers depending on N. The order N is usually about 8. See Moench and Ogata (1984) for more information.

The improvement starts with construction of a time series spaced apart by log102, for example to=O.1, tt=0.2, t2=0.4, t3=0.8, etc. In this way 27 times are required to cover 8 decades, as opposed to the 32 points used by Moench (1996). Fig. 2 illustrates the different spacings. For B= 10-2 the spacing is log102, whereas for B= 100 32 points are plotted.

When the arguments (Iri2/t)i of the Laplace transform are calculated for tn, it turns out that always half the arguments are exactly the same as for t~_l' Table 2 illustrates how this works. The first four arguments calculated for t=O.l are mapped into arguments with even i (2,4,6 and 8) for t=0.2 and the same is true for every other time step. Therefore for every time step, except the first one, Eqn (1) needs to be evaluated only >;,N times. The other half can be kept from the previous time step. Thus more than half the computational work is saved. Instead of computing 32 points in the Moench algorithm, an amount of work is required which is equivalent to computing 14 full points only. To determine points at any value between the evenly spaced t values, a cubic spline interpolation subroutine will produce fast results (Press et al., 1986). In fact the type curves of Fig. 2 are each composed of 320 points using cubic spline interpolation.

B. The roots of Eqn (2) are easily calculated,by means of the Newton-Raphson method. This method, however, works best'in the vicinity of the roots. It is therefore important to select good starting points, without spending too much time in selecting these points. The following subroutine (Table 3) tries to do that. For small a and with O<x< >;'17, the solution converges to "ra, so this is an obvious starting point. For larger a it seems better to choose arctan( a) as starting point. For all values of x> >;'17 a good starting point can be selected by adding 17 to.the previous root. For large values of a, the roots approach X=k17, whereas fo~ small

/

2

values of a the roots approach x= !;,11+ k 11. Note also that no. conditions are required to stop the inner iteration loop, should the number of iterations exceed a limit.

The performance of this subroutine is illustrated in Fig. 3, showing the average number of iterations required for a wide range of a values. The equivalent subroutine by Moench (1996) needs about 5 iterations for the entire range of a values to reach the same accuracy (1 e-10). Performance checks showed that the subroutine given here (Table 3) is twice as fast as Moench's subroutine for a=1.0e+2 and five times faster for a=1.0e-6.

C. The determination of the modified Bessel function K,,(x) is pretty much standard and it seems there is not much rbom for improvement here. Standard polynomial approximation to an accuracy of 1e-6 seems to work fine.

D. Summation of the terms in Eqn 1 should stop when sufficient accuracy is reached. As the value of 13 increases, the number of terms in the summation rises rapidly, which results in a substantial increase of runtimes. Moench (1996) shows that runtimes for type curve calculations with 13= le+ 2 are in the order of 1 second, whereas calculations with 13= le-4 require more than a minute.

Because Moeneh (1996) does not present absolute convergence criteria, it seems useful to briefly discuss the issue here. The summation of Eqn (1) may be written as follows:

s = f Ko(x,)f(e)

,,0 gee n) (4)

where

ft.e) = [sm(ae,)-sm(ben)][sm(ce)-sm(de n)] (5)

where a,b,c and d are constants (see Eqn. 1). Ko(xn) is a rapidlY decreasing function of xn and can be written as

-, H e' 1[ K(x)=- -

On Iv 2 VXn

for x,>5 (7)

Because the roots En approach (n-l) 11 for large n, the term sin(2 En) goes to zero and g( En) will go to l:i En' The term f( En) is normally oscillating as a function of the arguments, and therefore determines the sign of tl]e term to be added to S. However, for example when a=c and b=d in Eqn 4, then f( En) is greater than zero for all n. In all cases f( En) lies between -4 and +4.

3

Therefore the rest term Sk' which is equal to

Sk = E Ko(x,lf(E ,l "k g(E,)

(8)

is clearly less than

with x. = J~,,2(n-l)2 + p (9)

Because Ko decreases monotonically, it follows that

(10)

The summation in Eqn 10 can be approximated (for reasonably large k) by an integration from k to infinity, yielding

(11)

Hence the term on the right hand side of Eqn 11 gives an absolute criterion for convergence as a function of k, Band p.

In modelling practice Eqn 11 overestimates the error, as is illustrated in Table 4 for the type curve with B= 10-4 (Fig.2). Acceptable results may be reached with a summation of only 30 terms. This points out that in any particular case several orders of summation should be tried. For inverse modelling purposes, where high speed is important, it seems wise to use the lowest acceptable k first.

Discussion

It is suggested to calculate type curves points at spacings a factor 2 apart, because then the Stehfest inversion can be implemented more efficiently. This leads to a significant reduction in the amount of time required to compute the type curves in those cases where the evaluation of the Laplace transform is laborious (Eqn. 1), in the present case when B is small. It follows of course that it is not necessary to do so if only a few terms in Eqn. 1 are required (i.e. for large B). However, the generalization to wells of finite diameter (Moench, 1997) leads to even more complex expressions than Eqn. 1. Thus, it may in many cases be of advantage to change the type curve calculations in the manner suggested here.

The second improvement consists of selecting better initial values of the Newton­Raphson method to find the roots of Eqn (2) and streamlining the subroutine by discarding non-functional conditional statements.

4 I I

The algorithm, described here, was implemented in Turbo-7 Pascal (MSDOS), leading to the result shown in Fig. 4. Runtimes were in the order of 6 seconds, whereas the Aquifer Test Package (Windows 3.1), run on the same computer, needed 54 seconds. Moench (1996) indicates about 30 seconds for this problem.

Finally, it seems also necessary to further study the instability problems for small 13, mentioned by Moench (1997), for the generalized case of a finite well diameter.

References

Aquifer Test (1997) Well Test Analysis Package, Waterloo Hydrologic Software, Canada.

Moench, AF. and Ogata, A (1984). Analysis of constant discharge wells by numerical inversion of Laplace Transform solutions. In Groundwater Hydraulics, Water Resources Monograph Series. v. 9, 147-170.

Moench, AF. (1996) Flow to a Well in a Water-Table Aquifer: An Improved Laplace Transform Solution. Ground Water, 34 (4), 593-596.

Moench, AF. (1997) Flow to a well of finite diameter in a homogeneous, anisotropic water table aquifer. Water Resources Research, 33(6), 1397-1407.

Press, W.H., Flannery, B.P., Teukolsky, S.A and Vetterling, W.T. (1986) Numerical Recipes, The Art of Scientific Computing. Cambridge University Press, London, pp 818.

Stehfest, H. (1970) Numerical inversion of Laplace transforms. Communications ACM, 47-49.

5

Table 1. Dimensionless Expressions

to Tt/r2S

tOy Tt/r2Sy

ho 41TT(hj"h)/Q

ro rib Zo z/D Ko ~/K, ID I/b do d/b B K,r02/K, a S/Sy y delayed yield constant

6

Table 2 The table illustrates that half the arguments ofthe Stehfest algorithm are the same for each successive timestep, provided the spacing of points on the type curve is a factor 2

1 2 3 4 5 6 7 8

0.1 0.2 0.4

6.93__ 3.46__ 1.73 13.86~---- 6.93,--- 3.46 20.79 1O.40'\. '" 5.20 27.72~13.86~ '" 6.93 34.66 17.33 \. '\. 8.66 41.59 20.79 \"10.40 48.52 24.26 \12.13 55.45 27.72 13.86

Table 3 Subroutine for determining the roots of xtan(x) = a by the Newton-Raphson method.

begin {solutions to xtan(x)=a} eps:= le-ID; {accuracy of the Newton-Raphson method} n:=4DD; {number 6f terms for summation in Eqn (I)} a:=O.l; {assign value for a} if a<l then xz:=sqrt(a) else xz:=arctan(a); {starting points depending on a} for i: = 1 to n do begin

x:=xz; repeat

sx:=sin(x); cx:=cos(x); scx:=sx*cx; x: =x-(x*scx-a *cx*cx)/( sx*cx+x);

until (abs(ff)<eps); xz:=x+pi;

end; end;

{new starting point for all x> !:in}

8

I I

Table 4 Comparison of results for three different orders of summation (Eqn. 1) for B= 10-4 (see type curve Fig. 2). The relative error SJS relates to Eqns 4 and 11.

order k k=400 k=80 k=30 residual residual 400-80 400-30

SkiS =5e-7 =0.05 =0.3

loglo t o log10ho loglOho loglOho

-1. 00000 -0.32994 -0.33478 -0.36225 0.00484 0.03231 -0.69897 0.42900 0.42640 0.40241 0.00261 0.02659 -0.39794 0.88626 0.88496 0.86531 0.00l30 0.02095 -0.09691 1.17710 1.17640 1.16121 0.00070 0.01589 0.20412 1. 36982 1.36937 1. 35789 0.00045 0.01193 0.50515 1.50006 1. 49973 1.49084 0.00033 0.00923 0.80618 1.58825 1.58798 1.58069 0.00027 0.00756 1.10721 1.64731 1. 64708 1. 64072 0.00024 0.00659 1.40824 1.68498 1. 68477 1. 67894 0.00022 0.00604 1. 70927 1.70629 1.70608 1.70053 0.00021 0.00576 2.01030 1. 71662 1. 71642 1. 71099 0.00020 0.00563 2.31133 1. 72106 1.72086 1. 71547 0.00020 0.00559 2.61236 1. 72292 1. 72272 1. 71733 0.00020 0.00559 2.91339 1. 72387 1.72367 1. 71823 0.00020 0.00564 3.21442 1. 72471 1.72452 1. 71898 0.00019 0.00573 3.51545 1.72602 1. 72583 1.72014 0.00019 0.00588 3.81648 1.72840 1. 72821 1. 72240 0.00019 0.00600 4.11751 1. 73276 1.73257 1.72715 0.00019 0.00560 4.41854 1. 74033 1. 74014 1.73738 0.00019 0.00295 4.71957 1. 75218 1.75200 1. 74906 0.00018 0.00312 5.02060 1. 76792 1. 76774 1.76456 0.00018 0.00336 5.32163 1. 78489 1.78472 1.78174 0.00017 0.00315 5.62266 1. 79967 1. 79950 1.79661 0.00016 0.00306 5.92369 1. 81060 1. 81044 1. 80762 0.00016 0.00298 6.22472 1.81830 1. 81814 1. 81538 0.00016 0.00293 6.52575 1. 82419 1.82404 1.82131 0.00015 0.00289 6.82678 1. 82927 1. 82911 1. 82641 0.00015 0.00285

9

Figure Captions

Fig. 1 Configuration of small scale well test in water-table aquifer (Chiefs Island, Okavango Delta Botswana, research site).

Fig. 2 Type curves for 4 different B-values (Moench, 1996) showing the two different point spacings discussed in this paper.

Fig. 3 Number of iterations required by the Newton-Raphson algorithm to find the roots ofxtan(x)=a for a wide range of a values. The comparable subroutine by Moench (1996) will always need about 5 iterations.

Fig. 4 Results of composite well test (Fig. 1) for piezometers D and E.

10

1

0

r-..

E - 1 '-" (J) 0 -2 J2 '--::J (/)

~ -3

(J) .0 -4-.r::. +-Cl. <D -5.

'"0

-6

-7

D

solid

screen'

Figure 1

c E

0.47 m 0,225 m

water table

fine sand aquifer

• 27 steps of log 10 2 o 32 steps (4 per decade)

10-3 L--l---LLillill---L..J...LlJJl1L-LLLUlllL-Ll-'.illllL-LLWlllL.JLLlJJ.lllJ----"-JJ.J-'1llL----'-.LWLWl

10-1 10 1 103 105

107

Figure 2

Cl) 6 c 0 • :;:: 5 Q (J) ±:

4 "-0 n=lO n=400 ..... (J)

3 ..0 E

n=4000 ::J c 2 (J) 0)

Q 1 (J) > a 0

-8 -4 0 +4 +8 log 10 a

Figure 3

10' results

T 25,6 m2 /d

S 0,06

Sy 0,32 hD

Kr 5,12m/d

Kz 2,56 mid

'Y 3

Figure 4