HYDROGEOLOGICAL CHARACTERISATION AND PRELIMINARY GROUNDWATER QUALITY

ASSESSMENT FOR THE MOSMAN PENINSULA IN PERTH, WESTERN AUSTRALIA

JEANNETTE RÜMMLER,

ELISE BEKELE,

SIMON TOZE

WATER FOR A HEALTHY COUNTRY

National Research Flagship

HYDROGEOLOGICAL CHARACTERISATION AND PRELIMINARY GROUNDWATER QUALITY

ASSESSMENT FOR THE MOSMAN PENINSULA IN PERTH, WESTERN AUSTRALIA

JEANNETTE RÜMMLER,

ELISE BEKELE,

SIMON TOZE

WATER FOR A HEALTHY COUNTRY

National Research Flagship

 

 

  The Water for a Healthy Country National Research Flagship is a research partnership between CSIRO, state and federal governments, private and public industry and other research providers. The Flagship was established in 2003 as part of the CSIRO National Research Flagship Initiative. The work contained in this report is collaboration between CSIRO Land and Water and the Water Corporation of Western Australia. © Commonwealth of Australia 2005. All rights reserved. This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth. Citation: eg. Rümmler, J. et al., 2005. Hydrogeological Characterisation and Preliminary Groundwater Quality Assessment for the Mosman Peninsula in Perth, Western Australia. Client Report for Water Corporation, Western Australia. Water for a Healthy Country National Research Flagship CSIRO: Canberra. DISCLAIMER You accept all risks and responsibility for losses, damages, costs and other consequences resulting directly or indirectly from using this site and any information or material available from it. To the maximum permitted by law, CSIRO excludes all liability to any person arising directly or indirectly from using this site and any information or material available from it. For further information contact: Ph: 02 6246 4565 Fax: 02 6246 4564 www.csiro.au Printed 2005

Table of Contents Executive Summary ................................................................................................................... 1 Acknowledgements .................................................................................................................... 2 1. Introduction ............................................................................................................................ 2 2. General Hydrogeology ........................................................................................................... 3 3. Geological Data and Interpretation of Aquifer Variability .................................................... 5

3.1 Geological Data................................................................................................................ 5 3.2 Interpretation of Aquifer Variability ................................................................................ 6

4. Groundwater Monitoring........................................................................................................ 8 4.1 Existing Data .................................................................................................................... 8 4.2 Groundwater Monitoring Campaign September 2004 ..................................................... 9 4.2.1 Sampling and Measurement Techniques....................................................................... 9 4.2.2 Observations and Preliminary Insights ....................................................................... 10

5. Conclusions and Recommendations for Further Work ........................................................ 13 6. References ............................................................................................................................ 14 7. Figures.................................................................................................................................. 16 8. Tables ................................................................................................................................... 29 List of Figures Figure 1: Location of the study area and bores used for water quality monitoring program... 16 Figure 2: Generalised geology and stratigraphic cross-section of the Perth Basin.................. 17 Figure 3: Catchment areas of the Superficial formations of the Perth Basin........................... 18 Figure 4: Locations of bore log data and lines of section on the Mosman peninsula .............. 18 Figure 5: Cross-section A-A’ ................................................................................................... 19 Figure 6: Cross-section B-B’.................................................................................................... 20 Figure 7: Cross-section C-C’.................................................................................................... 21 Figure 8: Cross-section D-D’ ................................................................................................... 22 Figure 9: Cross-section E-E’ .................................................................................................... 23 Figure 10: Occurrences of Quaternary clay on the Mosman peninsula ................................... 24 Figure 11: Groundwater quality versus depth in IF2 ............................................................... 25 Figure 12: Groundwater quality versus depth in IF6 ............................................................... 26 Figure 13: Hydrochemistry data measured with the MP Troll 9000 in IF16. .......................... 27 Figure 14: Water level data for IF16, OBS1, and OBS2 bores and tide heights for Fremantle gauging station from the Oceanographic Office, Department for Planning and Infrastructure................................................................................................................................................... 28 List of Tables Table 1: Bore construction details for groundwater quality sampling in September 2004...... 29 Table 2: Water quality field measurements taken in September 2004..................................... 30 Table 3: Groundwater hydrochemistry and microbial analysis results from sampling in September 2004........................................................................................................................ 31

Executive Summary

Among the major initiatives by the Water Corporation of Western Australia to augment non-

potable groundwater supplies is a proposal to use managed aquifer recharge on the Mosman

peninsula to maintain irrigation supplies and mitigate saltwater intrusion; however, further

study is needed to characterise the hydrogeology of the Superficial aquifer and to expand the

knowledge base required to formulate predictive models of reclaimed water storage and reuse

on the peninsula. Previous work in this area involved a pre-feasibility study by PROMMER et

al. (2004) to develop a numerical model to predict the likely extent and impacts of managed

aquifer recharge on groundwater levels and water quality, accounting for current and

anticipated future users of groundwater. The final recommendations from this report

emphasized that the collection of additional data was necessary to improve the conceptual

model of the hydrostratigraphy, better define aquifer characteristics, and to calibrate and

validate the predictive model (PROMMER et al. 2004).

One of the objectives of this study was to compile available hydrogeological data from

various sources, including unpublished reports from the Water Corporation archives, drilling

reports obtained directly from private bore owners as well as Town/Shire Councils, and data

requests from the DEPARTMENT OF ENVIRONMENT Water Information (WIN) database. The

scope of this project also involved establishing a groundwater monitoring program to acquire

water quality and water level measurements at appropriate spatial and temporal scales that

would aid future model development. Although a recent change in strategic focus by Water

Corporation has led to postponing plans to continue monitoring on the Mosman peninsula,

this report provides results and interpretation from the first round of water quality sampling

from 28 bores conducted in September 2004. The groundwater analyses included

hydrochemical and microbial measurements. An in-situ water quality/water level data logger

was installed in one of the bores and monitored for three months to obtain a temporal

sequence of hydrochemistry and water level data. Another two bores were continuously

monitored for water levels as the majority of bores on the peninsula are used for irrigation.

This project completed the preparatory work necessary for developing a groundwater

monitoring program, which included identifying and selecting suitable bores for measuring

water quality and water level data. The DEPARTMENT OF ENVIRONMENT WIN database

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contained about 150 bores for the Mosman peninsula, including many private irrigation wells,

but from these, only a small fraction could be considered for the monitoring program based on

the completeness of the bore construction records and access to the bores.

There were also 90 bore logs collected and analyzed to construct geological cross-sections

and interpret the hydrostratigraphy. The analysis of existing bore logs described in this report

reveals that the conceptual model developed by PROMMER et al. (2004) should be amended to

account for a larger saturated thickness of the Superficial aquifer of at least 30 m and the

occurrences of clay predominantly along the east to southeast side of the peninsula at

relatively shallow depths.

The groundwater sampling campaign conducted in September 2004 included 25 bores that are

privately owned and 3 multi-port bores that provide depth profiles of the groundwater

hydrochemistry, which were constructed during the PERTH URBAN WATER BALANCE STUDY

(CARGEEG et al. 1987). The majority of groundwater samples were brackish (1000-10,000

mg/L TDS), while some of the deep samples from the multi-port bores are saline. Elevated

nitrate levels were detected in bores located at Scotch College where a local source of soil

contamination is suspected. The analyses reveal no microbial activity concerns based on the

groundwater samples that were taken. Although immediate plans to continue the monitoring

and sampling program for the Mosman peninsula have been suspended, the groundwork has

been set and the outcomes from this report include recommendations to aid future data

collection.

Acknowledgements

This work was funded jointly by CSIRO Land and Water under the Water for a Healthy

Country Flagship Program and the Water Corporation of Western Australia. The

participation and technical assistance of Mr Jon Hanna are gratefully acknowledged.

1. Introduction

The Water Corporation has proposed to augment non-potable water supplies on the

Mosman/Cottesloe peninsula on the Swan Coastal Plain by recharging the unconfined

Superficial aquifer with reclaimed water. The peninsula, commonly referred to as the

Mosman peninsula, includes the Shire of Peppermint Grove and the Towns of Cottesloe and

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Mosman Park. Managed aquifer recharge offers an opportunity to provide additional

irrigation supplies and to mitigate saltwater intrusion on the peninsula. The Superficial

aquifer is a multi-layered assemblage of late Tertiary to Quaternary coastal plain sediments

that provides groundwater mainly for irrigation supplies (DAVIDSON 1995). The health and

environmental impacts of managed aquifer recharge and the effects on the quality of

groundwater discharging into the Indian Ocean and Swan River are major concerns requiring

additional knowledge of the aquifer characteristics and groundwater flow patterns.

The scope of this study included a compilation of existing geological data, including bore logs

for interpreting aquifer variability and recently measured groundwater level and water quality

(hydrochemistry and microbial) data for the Superficial aquifer on the Mosman peninsula.

Prior to this work, a pre-feasibility study for managed aquifer recharge on the Mosman

peninsula was conducted by Australian Groundwater Technologies to assess the suitability of

the aquifer and to test scenarios for injecting reclaimed water into the aquifer for reuse

(PROMMER et al. 2004). Following on from the recommendations by PROMMER et al. (2004),

the present study aimed to increase our understanding of the Superficial aquifer and to

establish a groundwater monitoring program to quantify spatial and temporal changes in the

water table and groundwater quality. The groundwater information collected for this project

should provide context for any future proposals to develop a managed aquifer recharge project

on the peninsula.

2. General Hydrogeology

The Mosman peninsula, located about 11 km southwest of Perth, is a north-south trending

landmass bounded by the Indian Ocean to the west and the estuarine portion of the Swan

River to the east (Figure 1). The peninsula is part of the western side of the Perth Basin, a

trough of sedimentary deposits up to 12 km thick with coastal dune and recent alluvial

sediments within the uppermost section (Figure 2; PLAYFORD et al. 1976).

The groundwater catchment area for the Superficial aquifer is the Gnangara Mound (North)

(Figure 3). The water table is mostly below 1 m AHD and fluctuates seasonally by less than

about 1 m (PROMMER et al. 2004; APPLEYARD, personal communication). Groundwater

resources in the area are heavily dependent upon local recharge. Groundwater discharges to

the ocean and Swan River over a wedge of saltwater. The peninsula is completely underlain

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by saltwater and the maximum thickness of freshwater is about 15 m halfway between the

estuary and the ocean (CARGEEG et al. 1987). The interface between the fresh groundwater

and the wedge is a diffuse zone, 5 to 15 m thick, across which the groundwater salinity

increases from about 1000 mg/L to over 30000 mg/L (CARGEEG et al. 1987).

The Superficial aquifer on the peninsula consists of a core of Tamala Limestone, an eolianite

with a hard capping of secondary calcite overlain by variable depths of yellow or brown sand,

referred to as the Pleistocene Spearwood Dune System. The deposit was originally calcareous

to the surface, but continuous leaching has removed carbonate from the upper portions and

precipitated it deeper to form the hard capping (MCARTHUR and BETTENAY 1974).

According to DAVIDSON (1995), the Tamala Limestone is composed of a creamy white to

yellow, or light-grey, calcareous eolianite and it contains various proportions of mainly

medium-grained quartz sand, fine- to medium-grained shell fragments, and minor clayey

lenses. The limestone contains numerous solution channels and cavities, particularly in the

zone where the water table fluctuates, and in some areas there are karst structures. The

average thickness of the Superficial formations is 30 m and surface elevations range from 0 to

54 m AHD in the south and southeast portions of the peninsula (Figure 4).

In addition to the Tamala Limestone, there are exposed sections of Peppermint Grove

Limestone at Freshwater Bay on the banks of the Swan River near the Scotch College

boatshed. This limestone is dominated by sand-sized particles (calcarenite) and minor

amounts of limestone dominated by gravel-sized particles (calcirudite). The latter is generally

weakly lithified, apart from two well-cemented beds, which are thought to be beach rock

(PLAYFORD et al. 1976). The total thickness of the Peppermint Grove Limestone is 5 m. It

ranges in elevation from 1 to 7.3 m above sea level and interfingers with the Tamala

Limestone (PLAYFORD et al. 1976).

The Superficial aquifer has a maximum depth between -25 and -30 m AHD (CARGEEG et al.

1987, DAVIDSON 1995) and is unconformably underlain in the northern part of the peninsula

by the Cainozoic Kings Park Formation and in the south by the older Mesozoic Osborne

Formation. The Kings Park Formation and Kardinya Shale Member act as confining beds

(DAVIDSON 1995). The Kings Park Formation consists predominately of grey, calcareous and

glauconitic siltstone and shale of shallow-marine to estuarine origin. The maximum thickness

is about 530 m in the Claremont area west of Perth CBD. The Osborne Formation is of

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shallow-marine origin, and consists of a basal, weakly consolidated, comparatively thick

sandstone section (Henley Sandstone Member), the middle Kardinya Shale Member, a

siltstone-shale sequence with minor sandstone, and the upper Mirrabooka Member, a

sandstone-shale sequence (PLAYFORD et al. 1976; DAVIDSON 1995). The Mirrabooka

Member is eroded such that the Superficial aquifer is underlain by the Kardinya Shale

Member, which is approximately 80 m thick.

The hydraulic conductivity of the Superficial aquifer is between 40-100 m/day according to

measurements from the Perth region (CARGEEG et al. 1987). DAUBERMAN (2002) obtained

hydraulic conductivities that were on the order of 10-50 m/d for shallow soils at Cottesloe

Substation (corner of Curtin Avenue and Jarrad Street). RÜMMLER et al. (2005) obtained

saturated hydraulic conductivity estimates on the order of 2-35 m/d from sediment analysis of

cores that were collected at the CSIRO infiltration galleries site in Floreat. These data may

not be representative of the entire aquifer as there is considerable variability in hydraulic

properties due to solution cavities and karst features.

3. Geological Data and Interpretation of Aquifer Variability

3.1 Geological Data

Bore log descriptions were used to interpret the geology of the Superficial aquifer on the

Mosman peninsula and to assist with characterising the hydrogeology. There were 90 bore

logs used for this analysis, which are located on Figure 4. These data were mainly obtained

from the DEPARTMENT OF ENVIRONMENT WIN database. Data from the WATER

CORPORATION archive, namely the unpublished reports of the PERTH URBAN WATER

BALANCE, PROGRESS OF INVESTIGATIONS TO JULY 1984, and unpublished drilling reports from

the TOWN OF MOSMAN PARK, TOWN OF COTTESLOE, SHIRE OF PEPPERMINT GROVE, SEA VIEW

GOLF CLUB COTTESLOE, SCOTCH COLLEGE, WESTERN IRRIGATION, and STIRLING IRRIGATION

were also used. Lithology descriptions from different data sources were reviewed and similar

rock-type descriptions were grouped to develop a legend for the geologic cross-sections.

The most valuable bore log data for the detailed description of the hydrogeology were the

Interface bores IF2, IF3, IF4, IF5 and IF6, constructed during the PERTH URBAN WATER

BALANCE STUDY, and the following bores from the WIN database with IDs: 20020973,

5

20020836, 20020837, and 20030354, because these bores penetrate the whole Superficial

aquifer and terminate at depths between -25 and -30 m AHD in the underlying Osborne

Formation and Kings Park Formation, respectively. The other bore logs terminate within the

Superficial aquifer with maximum depths between -2 and -21 m AHD.

It was necessary to map the vertical position of bores along the geological cross-sections and

since there was a lack of surface elevation data a digital elevation model (DEM) was obtained

for the Mosman peninsula from POLLOCK (personal communication). In some instances, the

total drilled depths recorded in the WIN database were different from the unpublished drilling

reports. An average value for the total depth was used to construct the geologic cross-sections

for these bores. The bore logs from the WIN database and the DEM were displayed together

in ARC VIEW using coordinates in GDA-94. In order to have the same basis of surface

elevation data, the DEM values were used to prepare cross-sections and to calculate depths

below sea level. These elevations may differ by +/- 2 m from information in the reports due to

the 50 m x 50 m spatial resolution of the DEM.

3.2 Interpretation of Aquifer Variability

The location of the bore logs is shown in Figure 4 and geologic cross-sections (A to E) depict

variations in lithology (Figures 5 to 9). The most common lithologies are limestone and sand.

On the east side of the peninsula, there are 0.5-8 m-thick clay beds, which occur at depths

between -4 and -22 m AHD (Figures 7 and 10). In the WIN database, clay at depths between

-9 and -15 m AHD is commonly identified as, “Quaternary clay” (e.g. bore log 20019885 at -

15 m AHD in Figure 6) and sometimes identified as, “possible Kings Park Formation”. The

latter might actually be Quaternary clay since the depths are similar to the Quaternary clay

occurrences. Moreover, the Kings Park Formation is believed to be at a depth of at least -25

m AHD and the lithology of the Kings Park Formation includes siltstone and shale, not only

clay (DAVIDSON 1995).

The bore logs that are currently available do not provide evidence of a regionally extensive

clay layer within the Superficial aquifer, nor is there adequate information to determine

regional variations in the depth to the top of the underlying aquitard, either the Kings Park

Formation or shale-siltstone sections of the Osborne Formation. Clay occurrences are

6

predominantly along the east to southeast side of the peninsula and at relatively shallow

depths. The actual thickness of clay is difficult to determine because many of the bore logs

from the east side of the peninsula terminate in clay. The clay layers are often described as

thin and underlain by either limestone or sand (e.g. bore log 20029827 in Figure 7), or

alternating thin layers of clay and sand. Clay is less prevalent inland and along the west side

of the peninsula. Along the west side of the peninsula, only two of the fourteen bore logs

(20030355, 20020578) have clay below about -5 m AHD, as shown in cross-section D-D’

(Figure 8). The rhythmic stratification of clay and sand beds in bore log 20030355 appears to

be from Quaternary lake deposition. The greater prevalence of clay along the east side of the

peninsula is likely related to alluvial deposition. Additional drilling is needed to confirm the

distribution of clay and to determine the depth to the top of the Kings Park Formation.

An additional consideration is the occurrence of cavities and solution channels within the

limestone. A significant cavity over a 2 m interval exists in OBS1 at the Sea View Golf Club

(Figure 4). The water quality was observed to improve over this section (lower salinity).

There are also several solution cavities logged within a 6 m interval in OBS3, whereas in the

bore log for OBS2 there are no cavities (WATER DIRECT LIMITED 2004). Cavities were also

documented in the WIN database for bores 20021037, 20020008, 20020316 in the south-east

of the peninsula, and in bore 20029383 in the north-east, and at Nash Field Oval, Victoria

Street (Figure 4).

The preliminary conceptual model developed by PROMMER et al. (2004), which used bore logs

mainly from the east side of the peninsula, shows high permeability sand and limestone

sections of the Superficial aquifer underlain by a low permeability clay layer at a depth of -10

m. However, the recent review of existing bore logs conducted here does not reveal a

regionally extensive clay layer at this depth. Moreover, there are discontinuous layers of clay

interspersed within the aquifer. A uniform hydraulic conductivity of 100 m/day as applied in

the numerical model developed by PROMMER et al. (2004) was not intended to represent

heterogeneity due to cavities and clay lenses within the Superficial aquifer. It is likely that

the entire saturated thickness of the aquifer is at least 30 m, as shown from bore logs that

penetrate the whole aquifer without any clay occurrences. These results should be considered

in revising the conceptual model for the hydrogeology and in deciding where and how deep to

drill to improve our understanding of the geology.

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4. Groundwater Monitoring

4.1 Existing Data

As a first pass, historical groundwater level and groundwater quality data were obtained from

the DEPARTMENT OF ENVIRONMENT WIN database and the unpublished reports of the URBAN

WATER BALANCE PROGRESS OF INVESTIGATIONS TO JULY 1984. Overall, there was a lack of

sufficient data to describe temporal changes and spatial patterns in the groundwater data. The

only historical groundwater level map available for the Mosman peninsula is from June 1984

based on water levels from 37 domestic bores containing submersible pumps (APPLEYARD,

personal communication).

A search of the WIN database was conducted to identify suitable bores for long-term

monitoring of water levels and water quality. The WIN database bores (about 150 bores) are

predominantly private irrigation wells with fixed submergible pumps. The search revealed a

frequent lack of sufficient information regarding bore construction details (e.g. total depth and

screen depth), which are important to interpret water quality data, and the “owning authority”

which is required for gaining access and confirming the bore records. As a follow-up, local

councils (TOWNS OF COTTESLOE, MOSMAN PARK and THE SHIRE OF PEPPERMINT GROVE), and

private bore owners from the WIN database were contacted to request bore records and their

participation in the monitoring program. The bores were evaluated as to whether there were

sufficient bore construction records and easy access.

A selection of bores was identified to obtain a fairly good spatial distribution over the

Mosman peninsula. These include bores owned by the local Shire/Town Councils and Scotch

College, as well as observation bores at Sea View Golf Club. Figure 1 shows the bores which

were used during the first sampling campaign on 7-, 8-, and 9-September 2004 to collect

water quality and water level data. Table 1 provides bore construction details. From the

survey of available (non-domestic) bores for monitoring, we identified only three sites

(OBS1, OBS2 and IF16) that were available for measuring water levels.

The quality of data from some of the bores should be considered in view of the following

information. The irrigation bore COT_2 is located at the corner of Pearse Street and Curtin

Avenue, approximately 3 km from the sprinklers that were sampled. A period of 30 minutes

8

was allowed for the water to flush through the pipes as suggested by ROBINSON (personal

communication). Although the water quality data for COT_2 appears quite consistent with

nearest sampled bore, IF16, future monitoring should involve sufficient flushing and the water

quality data should be carefully evaluate for indications of any possible contamination within

the reticulation pipes. At Scotch College, there is an injection well near bore SCO_2, which

is used to infiltrate citric acid to control the pH of the groundwater for turf nutrient

management (CLIFFORD, personal communication). This appears to have impacted the

measured iron concentrations from the Scotch College bores. In all three bores (SCO_1,

SCO_2 and SCO_3), high ammonium concentrations were found and are likely related to a

local source of soil contamination.

As the majority of bores included in the hydrochemistry sampling program are used for

irrigation, it is worth confirming the schedule of watering in the event of future monitoring.

At the time of this report, there was insufficient information about the schedule of watering by

the Shire/Town Council and Sea View bores, which may be ad hoc, depending on the rainfall.

Scotch College follows a schedule of night watering during the summer beginning in

November; during the winter, the Scotch College bores were pumped for 20 minutes each

week to keep everything running (CLIFFORD, personal communication).

4.2 Groundwater Monitoring Campaign September 2004

During the sampling campaign in September 2004, groundwater samples were obtained from

28 bores locations (Figure 1), including the multi-port bores IF2 and IF6 which were used to

describe variations in the water quality with depth as well. The ports of IF2 and IF6 cover a

range of depths indicated in Table 1. The exact screen depths of some of the Shire/Town

Council bores and Scotch College bores were not known; however, bores in the area were

typically drilled to 10 m below the water table and the screen lengths are usually 6 m (YU,

personal communication). This information was used to estimate the screen depths where

construction details were insufficient.

4.2.1 Sampling and Measurement Techniques

Groundwater samples were mainly obtained from sprinklers because submergible pumps are

present in most of the bores, with one exception: at Scotch College, CLIFFORD (personal

9

communication) installed a tap to enable direct sampling from a couple of their bores. The IF

bores were sampled via a vacuum pump (BRAUNHOLZ, personal communication). The

groundwater was pumped out for about 10 minutes and afterwards samples were taken by

filling two 250 mL plastic bottles and one 10 mL glass bottle. The samples were kept cool

until they were analysed by the Western Australia Chemistry Centre. In addition, a 1-L

groundwater sample was collected and kept cool for conducting microbial analyses at CSIRO.

The analyses included total thermotolerant coliforms (TTC) and total heterotrophic counts

(THC). During sampling, the pump failed and no samples for microbial analysis were

obtained for OBS2. Not all of the ports on the IF multi-port bores were sampled for microbial

analyses due to time and because one sample from each multi-port was thought sufficient to

detect faecal contamination. Total heterotrophic counts for the samples from IF6 (10 m) and

PG_1 could not be determined accurately due to confluent growth of swarming bacteria.

Field measurements were also taken of groundwater pH, electrical conductivity (EC),

dissolved oxygen (DO), oxidation reduction potential (ORP/Eh), groundwater temperature,

and salinity using WTW (Wissenschaftlich-Technische Werkstätten) metering instruments.

Water quality field measurements were not taken in OBS1, OBS2 and IF16 because these

bores contained water level probes and loggers.

IF16, OBS1, and OBS2 are not used for irrigation and have no pumps in place; therefore, they

were fitted with electronic data loggers to monitor water level fluctuation. The loggers were

programmed to record every 15 minutes because high frequency monitoring is needed to

calculate tidal efficiencies of the aquifer. The probe in IF16 is the “MP Troll 9000 Pro XP”-

system, which also measures in-situ water chemistry. The measurements taken at 15-minute

intervals included groundwater temperature, pH, oxidation reduction potential (ORP),

dissolved oxygen, electrical conductivity (EC), and water levels.

4.2.2 Observations and Preliminary Insights Water Quality

The water quality field measurements and hydrochemistry analytical results are shown in

Tables 2 and 3. The groundwater temperatures in all bores were between 17.2 and 21.3 °C.

The oxygen values obtained from sprinklers were mostly between 5 and 7 mg/L, whereas the

values obtained from ports and taps were mostly between 0.6 and 3.8 mg/L (Table 2). The

10

higher dissolved oxygen values from sprinkler samples were caused by atmospheric oxygen

which is absorbed quickly by the groundwater. These values are likely inaccurate and should

be amended by installing taps rather than sampling from the sprinklers since it is important to

know the actual oxygen content of groundwater, particularly for nitrate removal. The

measured oxidation-reaction potentials (ORP) for the port and tap samples were between -17

and -37 mV and between -26 and -52 mV in samples taken from sprinklers. The difference of

ORP values between sprinkler and port/tap samples was not as significant as the difference in

dissolved oxygen values. The EC values measured in the field were between 0.83 and 49.10

mS/cm and the salinity values were between 0.20 and 31.8 ppt. The EC values for the IF

bores increased with depth due to the greater influence of seawater. The pH values measured

in the field range from 7.19 to 7.71. The water samples obtained from IF6 from the ports at

23 m and 27 m smelled of hydrogen sulphide, indicating strongly reducing conditions at

depth.

The hydrochemistry analytical results from the WA Chemistry Centre are shown in Table 3.

The measured DOC values ranged from 1 mg/L in bore COT_6 to 23 mg/L in IF6, port at 4

m. The measurements of pH taken in the lab vary between 7.3 and 8. Ammonium

concentrations were predominantly <0.01 mg/L or between 0.04 and 0.62 mg/L, with one

exception: 4.7 mg/L ammonium was sampled from bore SCO_1. The nitrate concentration of

the groundwater was <0.01mg/l in some bores or between 0.71 mg/L and 2.6 mg/L with a

maximum value of 4 mg/L in bore MOS_9. These values are reasonably high. In many of

the samples, phosphorus was below the detection limit (<0.01mg/L), while CO3

concentrations were <2 mg/L. The EC values were between 0.98 and 54.4 mS/cm, similar to

the field measurements. All values higher than 7 mS/cm were from the deep ports in IF2 and

IF6.

The range of measured concentrations were as follows: calcium (68.2-616 mg/L), sodium

(86.1-10900 mg/L), potassium (4.4-404 mg/L), magnesium (12.1-1330 mg/L), sulphate (26-

2800 mg/L), chloride (140 mg/L-21000 mg/L) and TDS (450-35000 mg/L); the

concentrations of these constituents increased with depth in the IF multi-port bores. Depth

profiles of the hydrochemistry data for two of the mulit-port bores (IF2 and IF6) are shown in

Figures 11 and 12. The HCO3 concentrations ranged from 177 to 573 mg/L. Iron

concentrations were between 0.005 and 2.6 mg/L, with the highest Fe values sampled from

11

the three bores at Scotch College, which are influenced most probably by the citric acid

treatment applied to the turf grass.

A temporal sequence of hydrochemistry data was obtained from 7-September to 14-

November with the MP Troll in IF16 (Figure 13). The MP Troll was installed 3 m below the

water table at a depth of about 17.6 m below ground level. During this period, the

groundwater temperatures showed a steady rising trend from about 21.85 to 21.92 °C with

accompanying diurnal fluctuations. The data from the other water quality parameters is

harder to interpret. There appear to be problems arising from possible drift in sensor readings

or build-up of material on the probes, which require further investigation. There is also a shift

toward greater spikiness in the sensor readings for temperature, pH, EC and DO after the last

battery change on 26-October. Although water levels were responsive to tidal fluctuations as

shown in Figure 14, the variability in the hydrochemistry data is less readily understood. The

EC readings were all fairly low (0.98-1.70 mS/cm) in comparison to the one analytical result

obtained in early September for IF16 (1.71 mS/cm), corresponding to 840 mg/L TDS. The

water quality in IF16 does not appear to be influenced significantly by mixing with seawater.

The results from the microbial analyses reveal that the thermotolerant coliform counts are all

well below the drinking water standard of 1 colony forming unit/100 mL (Table 3). The total

heterotrophic counts are quite variable. THC covers a broad group of bacteria and provides a

rough indication of water quality in terms of the abundance of bacteria and nutrient levels.

The samples from IF16, IF2 (14m) and OBS1 have high THCs that might be worth

investigating further for possible pathogens.

Groundwater Levels

At the three locations for water level monitoring, the following depths to water were recorded

as of 7-September 2004: OBS1 (24.28 m), OBS2 (10.46 m), and IF16 (14.62 m). The water

level data from the loggers in these bores are shown in Figure 14. A preliminary analysis of

tidal efficiencies for the two OBS bores was conducted from the groundwater level data and

tide height data provided by the OCEANOGRAPHIC OFFICE OF THE DEPARTMENT FOR PLANNING

AND INFRASTRUCTURE. The tidal efficiency is the ratio of changes in the amplitude of head

fluctuations in a coastal aquifer to fluctuations in the ocean tides as described in DOMENICO

AND SCHWARTZ (1990) and in early studies by JACOB (1940) and CARR AND VAN DER KAMP

12

(1969). The available data indicate a decrease in tidal efficiency along the transect connecting

OBS1 and OBS2, that is likely related to tidal energy dissipating inland through the aquifer,

but a longer record of water levels is needed to confirm the magnitude. A larger program of

water level monitoring along a transect of bores would enable a more accurate estimation of

aquifer diffusivity values and possibly transmissivity from tidal forcing theory. Tidal

analyses have been used recently to investigate hydraulic properties of the Tamala Limestone

in SMITH (1999), SMITH AND HICK (2001) and TREFRY AND BEKELE (2004).

5. Conclusions and Recommendations for Further Work

The proposal to augment non-potable groundwater supplies using managed aquifer recharge

on the Mosman peninsula will require additional data collection beyond the scope of this

preliminary investigation. Our aim has been to increase the knowledge base required to

model reclaimed water storage and reuse. We can conclude from the analysis of the physical

hydrogeology from bore logs that several refinements to the conceptual model developed by

PROMMER et al (2004) are needed, particularly with regard to the hydrostratigraphy. The first

round of water quality data reveal significant variations in time and space that will require

further monitoring over an extended period to help with calibrating a groundwater flow model

for the Mosman peninsula.

At the time this report was prepared, a decision was made by Water Corporation and CSIRO

to postpone plans for groundwater monitoring on the Mosman peninsula for the foreseeable

future. This was in response to strategic planning to pursue water reuse benefits elsewhere on

the coastal plain. The following recommendation should be considered if there is renewed

interest in pursuing a water reuse scheme on the peninsula at a later date.

The conceptual model for the hydrogeology of the Mosman peninsula would be greatly

improved by additional drilling to confirm the distribution of clay and to map the depth to the

top of the underlying aquitard, either the Kings Park Formation or shale-siltstone sections of

the Osborne Formation. Additional drilling and installation of a network of observation bores

for water level monitoring is also needed.

During the search for bores to sample for water quality, several bores were identified in the

Town of Mosman Park that have adequate bore construction details, but were not included in

13

the first sampling campaign due to time constraints. These bores should be considered for

future water sampling on the peninsula, if a larger coverage of water quality data is needed:

Swansea Bore, Wright Park Bore, Stringfellow Bore 1, Stringfellow Bore 2, E.G. Smith

Reserve Bore 1, and E.G. Smith Reserve Bore 2, which are all maintained by CURTIS

(personal communication).

It is also recommended that approval from the Shire/Town Councils should be sought to

install sampling taps where sprinkler heads are currently the only means available for

sampling groundwater. The background nitrate concentrations were reasonable high; hence it

is important to measure correct oxygen and ORP values of the groundwater, as it will be

necessary to evaluate nitrate enrichment/degradation during managed aquifer recharge.

6. References

CARGEEG G. C., BOUGHTON G. N., TOWNLEY L. R., SMITH G. R., APPLEYARD S. J. AND SMITH

R. A. (1987): Perth Urban Water Balance Study, Volume 1 – Findings. Water

Authority of Western Australia.

CARR P. A. AND VAN DER KAMP G. S. (1969): Determining aquifer characteristics by the tidal

method. Water Resources Research, 5(5), 1023-1031.

DAUBERMAN K. (2002): Assessment of LNAPL movement from transformer leaks in

Cottesloe Sand. Honours Project, Department of Environmental Engineering, The

University of Western Australia.

DAVIDSON W. A. (1995): Hydrogeology and groundwater resources of the Perth Region,

Western Australia. Geological Survey of Western Australia, Bulletin 142. p. 54.

DEPARTMENT OF ENVIRONMENT: WIN database, extracted July/August 2004.

DOMENICO P. A. AND SCHWARTZ F. W. (1990): Physical and Chemical Hydrogeology. John

Wiley and Sons, Inc., 824 pp.

JACOB, C. E. (1940): On the flow of water in an elastic artesian aquifer. Transactions,

American Geophysical Union, v. 22, 574-586.

MCARTHUR W. M. AND BETTENAY E. (1974): The development and distribution of the soils of

the Swan Coastal Plain, Western Australia. CSIRO, Melbourne, Soil Publication No.

16, second printing.

PERTH URBAN WATER BALANCE, PROGRESS OF INVESTIGATIONS TO JULY 1984, HF 417, File

1204.18, Volume 3; HF 399, File 1204.17. Water Corporation, unpublished.

14

PLAYFORD P. E., COCKBAIN A. E. AND LOW G. H. (1976): Geology of the Perth Basin Western

Australia. Geological Survey of Western Australia, Bulletin 124.

PROMMER H., BARBER C., SIBENALER X. AND BLAIR P. (2004): Mosman Reclaimed Water

Prefeasibility Study. Australian Groundwater Technologies, Report No. 2004/6.

unpublished.

RÜMMLER J., BEKELE E. AND TOZE S. (2005): Preliminary Hydrogeological Characterisation

for Proposed Covered Infiltration Galleries at CSIRO Laboratory, Floreat, Western

Australia. Technical Report, Water for a Healthy Country National Research

Flagship CSIRO: Canberra.

SMITH A. J. (1999): Application of a Tidal Method for Estimating Aquifer Diffusivity: Swan

River, Western Australia. CSIRO Land and Water Technical Report No. 13/99.

SMITH A. J. AND HICK W. P. (2001): Hydrogeology and Aquifer Tidal Propagation in

Cockburn Sound, Western Australia. CSIRO Land and Water Technical Report No.

6/01.

TREFRY M. G. AND BEKELE E. (2004): Structural characterization of an island aquifer via tidal

methods. Water Resources Research, 40(1) W01505, 10.1029/2003WR002003.

WATER CORPORATION, archive Perth Urban Water Balance Study (1985-1987)

WATER DIRECT LIMITED (2004): Water supply investigation Seaview Golf Club Cottesloe for

Seaview Golf Club. Job No. SGC/FRA/203, Report 001/v2, unpublished and

confidential.

PERSONAL COMMUNICATION:

- APPLEYARD, STEVE; Senior Hydrogeologist, Department of Environment, Perth

- BLYTHE, MATT; Works Supervisor, Town of Cottesloe

- BRAUNHOLZ, IAN; Contract staff, Department of Environment

- CLIFFORD, DAVID; Groundsman, Scotch College

- CURTIS, STUART; Groundsman, Town of Mosman Park

- POLLOCK, DANIEL; CSIRO Land and Water, Perth

- ROBINSON, PAUL; Groundsman, Town of Cottesloe

- XIENWEN YU; Groundwater Hydrology Section, Department of Environment, Perth

15

7. Figures

Cot 3

Cot 4 Cot 6

Cot 7

Cot 8

Obs 1

IF 2IF 16 IF 6

Mos 1Mos 2

Mos 3

Mos 4

Mos 5Mos 6

Mos 7

Mos 8

Mos 9

Mos 10

Mos 11

Pg 1Cot 1

Swan R i ve r

Obs 2Cot 2

Cot 5

I N D I A N

O C E A N

COTTESLOE

PEPPERMINTGROVE

MOSMAN PARK

RAI

LWAY

N

Stirl

ing

High

way

Curti

n Av

e

North St

Wes

t Coa

st H

wy

Sea ViewGolf Club

Eric st

CLAREMONT

Sco 1

Sco 3

Sco 2 ScotchCollegeConducted by CSIRO, Land and Water, October 2004

Map source: UBD Perth 2004 Street Directory

Bore for water quality sample(Obs 1+2, IF 16 for water level as well)

Mosman Peninsula

0 500 1000m

Figure 1: Location of the study area and bores used for water quality monitoring program

16

Figure 2: Generalised geology and stratigraphic cross-section of the Perth Basin

17

Figure 3: Catchment areas of the Superficial formations of the Perth Basin

Figure 4: Locations of bore log data and lines of section on the Mosman peninsula

18

Figure 5: Cross-section A-A’

San

d

Lim

esto

ne

Sha

le

Cla

y

San

dsto

ne

Bac

kfill

Not

logg

ed

Cav

ities

Logg

ed a

s O

sbor

ne F

orm

atio

n (in

terb

edde

dsa

ndst

one,

silt

ston

e, s

hale

and

cla

ysto

ne -

afte

rP

layf

ord

et a

l., 1

976)

LEG

END

020

040

060

080

010

0012

0014

0016

0018

00

30 20 10

0

-10

-20

-30

-40

-50

2000

2200

IF3

2002

0836

2001

9879

2002

0276

IF6

30 20 10 0 -10

-20

-30

-40

-50

AA’

IF2

Heightabovesealevel[mAHD]

Leng

th [m

]

2001

9990

2002

0273

19

Figure 6: Cross-section B-B’

020

040

060

080

010

0012

0014

0016

0018

00

40 20 10

0

-10

-20

-30

-40

-50

2000

2200

2002

0456

30 20 10 0 -10

-20

-30

-40

-50

BB

’

IF4

Heightabovesealevel[mAHD]

Leng

th [m

]24

00

20019885

20020316

3050

4050

2002

0825

2002

0837

2002

0789

2002

0520

20019994

20

Figure 7: Cross-section C-C’

075

012

5017

50

40 20 10 0

-10

-20

-30

-40

-50

2250

30 20 10 0 -10

-20

-30

-40

-50

CC

’

Heightabovesealevel[mAHD]

Leng

th [m

]27

5032

50

2001

9998

20020006

3050

405020

0293

852002

9472

2002

9829

2002

960820

0298

74 2002

9604

2002

9601

2002

0276

IF6

2002

0520

20020005

3750

4250

4500

2002

0456

20020311

20020973

2002

9827

250

2002

9383

2001

9887

IF5

21

075

012

5017

50

40 20 10

0

-10

-20

-30

-40

-50

2250

30 20 10 0 -10

-20

-30

-40

-50

DD

’

Heightabovesealevel[mAHD]

Leng

th [m

]27

5032

50

3050

4050

3750

4000

250

20030039

20029396

20030354

2003

0355

2002

9397

2003

0010

Obs

3O

bs1

2001

9979

2001

9990

2001

9978

2002

0578

2002

0009

20020588

15

Figure 8: Cross-section D-D’

22

Figure 9: Cross-section E-E’

200

400

600

800

1000

1200

1400

1600

1800

2000

50 40 30 20 10

0

-10

-20

-30

-40

-50

E

20029398

20029476

20030039

Heightabovesealevel[mAHD]

Leng

th [m

]

50 40 30 20 10 0 -10

-20

-30

-40

-50

E’

20030354

20030012

20030698

23

Figure 10: Occurrences of Quaternary clay on the Mosman peninsula

24

0

5

10

15

20

25

30

0 100 200 300 400 500 600 700

dept

h m

AH

DCa [mg/L] K [mg/L]

0

5

10

15

20

25

30

0 3500 7000 10500 14000 17500 21000

dept

h m

AH

D

Cl [mg/L] Na [mg/L]

0

5

10

15

20

25

30

3 4 5 6 7 8

dept

h m

AH

D

DOC [mg/L]

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50 55 60

dept

h m

AH

D

EC [mS/cm]

0

5

10

15

20

25

30

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

dept

h m

AH

D

Fe [mg/L]

0

5

10

15

20

25

30

150 175 200 225 250 275 300

dept

h m

AH

D

HCO3 [mg/L]

0

5

10

15

20

25

30

0 200 400 600 800 1000 1200 1400

dept

h m

AH

D

Mg [mg/L]

0

5

10

15

20

25

30

0 0.05 0.1 0.15 0.2

dept

h m

AH

D

N_NH3 [mg/L]

0

5

10

15

20

25

30

0 0.5 1 1.5 2 2.5

dept

h m

AH

D

N_NO3 [mg/L]

0

5

10

15

20

25

30

0 500 1000 1500 2000 2500 3000

dept

h m

AH

D

SO4_S [mg/L]

0

5

10

15

20

25

30

0 5000 10000 15000 20000 25000 30000 35000 40000

dept

h m

AH

D

TDS_180C [mg/L]

0

5

10

15

20

25

30

7.3 7.4 7.5 7.6 7.7 7.8

dept

h m

AH

D

pH

Figure 11: Groundwater quality versus depth in IF2

25

0

5

10

15

20

25

30

0 100 200 300 400 500 600 700

dept

h m

AH

DCa [mg/L] K [mg/L]

0

5

10

15

20

25

30

0 3500 7000 10500 14000 17500 21000

dept

h m

AH

D

Cl [mg/L] Na [mg/L]

0

5

10

15

20

25

30

0 5 10 15 20 25

dept

h m

AH

D

DOC [mg/L]

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50 55 60

dept

h m

AH

D

EC [mS/cm]

0

5

10

15

20

25

30

0 1 2 3 4 5 6 7 8 9

dept

h m

AH

D

Fe [mg/L]

0

5

10

15

20

25

30

200 250 300 350 400 450 500 550 600

dept

h m

AH

D

HCO3 [mg/L]

0

5

10

15

20

25

30

0 200 400 600 800 1000 1200 1400

dept

h m

AH

D

Mg [mg/L]

0

5

10

15

20

25

30

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

dept

h m

AH

D

N_NH3 [mg/L]

0

5

10

15

20

25

30

0 500 1000 1500 2000 2500 3000

dept

h m

AH

D

SO4_S [mg/L]

0

5

10

15

20

25

30

0 5000 10000 15000 20000 25000 30000 35000 40000

dept

h m

AH

D

TDS_180C [mg/L]

0

5

10

15

20

25

30

7.2 7.3 7.4 7.5 7.6 7.7 7.8

dept

h m

AH

D

pH

Figure 12: Groundwater quality versus depth in IF6

26

21.8221.84

21.8621.8821.9

21.9221.9421.96

21.9822

8/09/2004 24/09/2004 10/10/2004 26/10/2004 11/11/2004

Tem

pera

ture

(deg

C)

950

1050

1150

1250

1350

1450

1550

1650

1750

8/09/2004 24/09/2004 10/10/2004 26/10/2004 11/11/2004

EC ( µ

S/cm

)6.5

6.55

6.6

6.65

6.7

6.75

6.8

6.85

6.9

8/09/2004 24/09/2004 10/10/2004 26/10/2004 11/11/2004

pH

0

500

1000

1500

8/09/2004 24/09/2004 10/10/2004 26/10/2004 11/11/2004D

O ( µ

g/L)

-400

-300

-200

-100

0

100

200

300

8/09/2004 24/09/2004 10/10/2004 26/10/2004 11/11/2004

OR

P (m

V)

Figure 13: Hydrochemistry data measured with the MP Troll 9000 in IF16.

27

0

0.5

1

1.5

2

6/09/2004 16/09/2004 26/09/2004 6/10/2004 16/10/2004 26/10/2004 5/11/2004 15/11/2004

Date

Wat

er L

evel

(mA

HD

)

-0.84

-0.64

-0.44

-0.24

-0.04

0.16

0.36

0.56

0.76

Tide

Hei

ght (

mA

HD

)

IF16OBS1OBS2Fremantle Tides

Figure 14: Water level data for IF16, OBS1, and OBS2 bores and tide heights for Fremantle gauging station from the Oceanographic Office, Department for Planning and Infrastructure.

28

8. Tables Table 1: Bore construction details for groundwater quality sampling in September 2004.

Name Drilled depth (m)

Construction element

Depth to pump (m)

Depth to screen top (m)

Screen length (m)

COT_1 37.9 Screen 31 28 6

COT_2 20.5 Screen 16.32 13.32 6

COT_3 23.72 Screen 20.83 17.83 6

COT_4 approx. 40 Screen approx. 40 34 6

COT_5 33.90 Screen 27.6 24.6 6

COT_6 43.20 Screen 36.25 33.25 6

COT_7 approx. 51 Screen 46.8 43.8 6

COT_8 35.25 Screen 28.6 25.6 6

IF2, 14m 40.7 Port -- 14 --

IF2, 17m 40.7 Port -- 17 --

IF2, 20m 40.7 Port -- 20 --

IF2, 23m 40.7 Port -- 23 --

IF2, 26m 40.7 Port -- 26 --

IF2, 33m 40.7 Port -- 33 --

IF6, 4m 39 Port -- 4 --

IF6, 7m 39 Port -- 7 --

IF6, 10m 39 Port -- 10 --

IF6, 16m 39 Port -- 16 --

IF6, 23m 39 Port -- 23 --

IF6, 27m 39 Port -- 27 --

IF16 26 Screen -- 14 12

MOS_1 27 Screen -- 18.4 6

MOS_2 45.25 Screen -- 42.25 3

MOS_3 47.30 Screen -- 44.1 3.2

MOS_4 29.81 Screen -- 26.68 3.13

MOS_5 12.2 Screen -- 8.6 3.6

MOS_6 25.9 Screen -- 19.85 6.

MOS_7 37.15 Screen -- 30.95 6

MOS_8 28.10 Screen -- 23.45 4.65

MOS_9 38.70 Screen -- 35.5 3.2

MOS_10 25.80 Screen -- 22.63 3.17

MOS_11 29.95 Screen -- 23.95 4

OBS1 38 Screen -- 15 13

OBS2 26 Screen -- 11 13

PG_1 NA Screen -- 9.5 3.2

SCO_1 19.85 Screen -- 13.85 6

SCO_2 28.50 Screen -- 22.5 6

SCO_3 42.2 Screen -- 37.35 4.85 *There is no information about the well screens for the COT bores. We assumed 6 m screen lengths based on YU (personal communication), and assumed the depth to the pump is equivalent to the midpoint of the screen to estimate the depth to the screen. The screen lengths are unknown for the MOS bores. We assumed either the screen lengths are 6 m or less than 6 m to reach the total drilled depth.

29

30

Table 2: Water quality field measurements taken in September 2004. Water quality measurements were not collected for the three bores being monitored for groundwater levels.

sample ID date sample obtained from

pH EC [mS/cm]

DO [mg/L]*

ORP/Eh [mV]*

Temp [°C]

Salinity [ppt] comments

COT_1 09.09.2005 sprinkler 7.72 2.08 5.40 -46.00 19.8 0.90

COT_2 09.09.2005 sprinkler 7.84 1.43 6.50 -52.00 17.2 0.50

COT_3 09.09.2005 sprinkler 7.74 1.88 5.00 -46.00 18.8 0.80

COT_4 09.09.2005 sprinkler 7.86 1.30 5.10 -52.00 19.3 0.40

COT_5 09.09.2005 sprinkler 7.62 2.22 4.90 -39.00 19.6 1.00

COT_6 09.09.2005 sprinkler 7.68 2.25 4.90 -42.00 19.6 1.00

COT_7 09.09.2005 sprinkler 7.78 1.06 5.20 -48.00 20.2 0.30

COT_8 09.09.2005 sprinkler 7.73 1.51 5.10 -45.00 19.5 0.60

IF2, 14m 07.09.2004 bore port 7.63 2.92 3.80 -30.00 20.0 1.40

IF2, 17m 07.09.2004 bore port 7.54 8.43 1.90 -25.00 20.6 4.70

IF2, 20m 07.09.2004 bore port 7.57 12.34 1.30 -27.00 20.9 7.10

IF2, 23m 07.09.2004 bore port 7.52 38.80 0.70 -25.00 20.4 24.50

IF2, 26m 07.09.2004 bore port 7.46 37.20 0.70 -21.00 20.9 23.40

IF2, 33m 07.09.2004 bore port 7.48 49.10 0.60 -22.00 20.8 31.80

IF6, 4m 07.09.2004 bore port 7.44 6.00 3.00 -21.00 17.9 3.20

IF6, 7m 07.09.2004 bore port 7.58 4.79 3.00 -27.00 19.2 2.50

IF6, 10m 07.09.2004 bore port 7.55 21.40 1.50 -26.00 19.6 12.80

IF6, 16m 07.09.2004 bore port 7.40 46.50 2.20 -17.00 19.7 29.90

IF6, 23m 07.09.2004 bore port 7.44 48.60 3.10 -19.00 19.7 31.40 H2S smell

IF6, 27m 07.09.2004 bore port 7.47 49.10 2.80 -21.00 19.8 31.80 H2S smell

IF16 07.09.2004 bore probe probe probe probe probe probe plus water level

MOS_1 08.09.2005 sprinkler 7.79 2.57 5.30 -40.00 20.3 1.20

MOS_2 08.09.2005 sprinkler 7.74 1.69 5.50 -40.00 21.1 0.70

MOS_3 08.09.2005 sprinkler 7.71 1.55 5.50 -44.00 20.6 0.60

MOS_4 08.09.2005 sprinkler 7.38 2.20 5.40 -26.00 21.3 0.90

MOS_5 08.09.2005 sprinkler 7.83 0.83 5.90 -52.00 19.7 0.20

MOS_6 08.09.2005 sprinkler 7.70 1.69 6.40 -44.00 20.2 0.70

MOS_7 08.09.2005 sprinkler 7.75 1.80 6.30 -47.00 20.1 0.70

MOS_8 08.09.2005 sprinkler 7.60 1.93 6.40 -38.00 20.3 0.80

MOS_9 08.09.2005 sprinkler 7.61 2.29 7.00 -39.00 20.5 1.00

MOS_10 08.09.2005 sprinkler 7.79 2.14 7.00 -49.00 19.7 0.90

MOS_11 08.09.2005 sprinkler 7.77 2.23 6.70 -48.00 19.8 1.00

OBS1 07.09.2004 bore probe probe probe probe probe probe plus water level

OBS2 07.09.2004 bore probe probe probe probe probe probe plus water level

PG_1 09.09.2005 sprinkler 7.64 3.08 5.30 -41.00 19.3 1.50

SCO_1 09.09.2005 tap pump 7.58 1.70 6.60 -37.00 18.4 0.70

SCO_2 09.09.2005 tap pump 7.19 1.17 1.80 -16.00 20.7 0.40

SCO_3 09.09.2005 tap pump 7.36 1.08 1.50 -24.00 20.6 0.30

Table 3: Groundwater hydrochemistry and microbial analysis results from sampling in September 2004

Sample ID

Total Hetero-trophic Counts (THC/mL)

Thermo-tolerant Coliforms TTC/100 mL

CO3 [mg/L]

Ca [mg/L]

Cl [mg/L]

DOC [mg/L]

EC [mS/cm]

Fe [mg/L]

HCO3 [mg/L]

K [mg/L]

Mg [mg/L]

N_NH3 [mg/L]

N_NO3 [mg/L]

Na [mg/L]

P_SR [mg/L]

SO4_S [mg/L]

TDS_ 180C [mg/L]

pH

COT_1 943 0.2 <2 114 580 2 2.52 0.01 305 13.1 38.6 <0.01 2.3 315 <0.01 78.2 3200 8 COT_2 1197 0 <2 106 340 3 1.74 0.015 281 9.2 22.5 <0.01 1.9 192 <0.01 54.3 930 8 COT_3 673 0 <2 117 450 4 2.27 0.022 320 11.1 30.5 <0.01 1.3 279 <0.01 73.1 1300 7.7 COT_4 220 0 <2 101 290 5 1.58 0.033 323 9.1 24.5 <0.01 2.6 170 <0.01 51.2 720 8 COT_5 23 0 <2 134 660 7 3.11 0.01 311 16.4 45.1 <0.01 1.9 365 <0.01 101 1600 8 COT_6 1270 0.2 <2 127 720 1 3.09 0.091 342 15.6 45.3 <0.01 1 373 <0.01 97.7 1600 8 COT_7 53 0 <2 99.3 220 3 1.29 0.015 317 7.4 17.5 <0.01 1.4 121 <0.01 47 660 7.9 COT_8 147 0 <2 114 350 5 1.84 0.07 308 10.1 25 <0.01 1.9 200 <0.01 66.5 920 8.1 IF2 14m 17233 0 <2 108 680 7 3.14 0.008 275 15.7 50.9 0.12 2.1 392 <0.01 100 2700 7.7 IF2 17m Not sampled Not sampled <2 172 3200 6 11.2 0.007 275 67.6 205 0.18 2 1760 0.01 413 6000 7.6 IF2 20m Not sampled Not sampled <2 205 5000 6 17.2 0.008 268 108 333 0.04 1.5 2880 0.01 704 9300 7.5 IF2 23m Not sampled Not sampled <2 372 16000 4 43.7 0.005 220 325 1000 <0.01 0.59 8420 0.03 2110 26000 7.7 IF2 26m Not sampled Not sampled <2 438 18000 6 47.6 0.02 220 375 1200 0.14 0.11 9780 0.04 2480 30000 7.5 IF2 33m Not sampled Not sampled <2 546 21000 5 54.4 0.34 177 404 1330 0.14 <0.01 10900 <0.01 2800 35000 7.6 IF6 4m Not sampled Not sampled <2 223 1700 23 6.91 7.9 573 49.6 123 0.21 <0.01 960 <0.01 379 3700 7.3 IF6 7m Not sampled Not sampled <2 141 1400 16 5.51 1.3 476 53.4 116 0.06 <0.01 742 <0.01 277 3000 7.6 IF6 10m Not sampled 0 <2 237 8400 7 25.8 1.5 311 193 491 0.32 <0.01 4700 <0.01 1090 14000 7.7 IF6 16m Not sampled Not sampled <2 616 18000 5 50.5 0.61 253 336 1240 0.62 <0.01 9910 <0.01 2570 31000 7.3 IF6 23m Not sampled Not sampled <2 586 19000 4 53 0.56 223 378 1300 0.53 <0.01 10500 <0.01 2710 35000 7.5 IF6 27m Not sampled Not sampled <2 585 20000 4 53.6 0.18 229 377 1300 0.45 <0.01 10400 <0.01 2660 35000 7.5 IF16 17167 0 <2 105 330 4 1.71 0.027 268 9.3 22.6 <0.01 1.5 191 <0.01 54.2 840 7.8 MOS_1 460 0 <2 136 620 5 2.93 0.027 311 15.3 45.8 <0.01 1.9 372 <0.01 138 2700 8 MOS_2 217 0.2 <2 98 410 4 1.98 0.021 287 13.3 31.6 <0.01 1.7 233 <0.01 58.4 960 8 MOS_3 563 0.2 <2 96.7 400 4 1.84 0.16 275 9.4 27.5 <0.01 2.1 211 <0.01 54.6 980 8 MOS_4 543 0 <2 102 520 4 2.38 0.012 262 11.9 35 <0.01 2.3 299 <0.01 77.5 1200 7.9 MOS_5 100 0 <2 83.1 140 5 0.98 0.005 256 6.6 12.1 <0.01 0.86 86.1 <0.01 37.6 540 8.1 MOS_6 213 0 <2 124 410 5 2.01 0.011 332 12.2 26.7 <0.01 1.6 225 <0.01 65.3 1100 7.9 MOS_7 60 0 <2 126 440 6 2.13 0.041 308 12.4 27.8 <0.01 2.7 247 <0.01 81.6 1100 7.9 MOS_8 190 0 <2 68.2 510 7 2.27 0.72 281 12.5 20 <0.01 0.71 345 <0.01 58.5 1100 7.8 MOS_9 63 0.2 <2 180 610 4 3.2 0.012 323 7.8 36.9 <0.01 4 363 <0.01 103 1600 7.7 MOS_10 123 0 <2 122 570 4 2.56 <0.005 305 14.3 34.2 <0.01 2.1 317 <0.01 89.2 1400 7.8 MOS_11 50 0 <2 131 660 4 2.89 0.016 314 15 38.3 <0.01 1.8 368 <0.01 98.9 1500 7.9 OBS 1 10233 0 <2 88.8 160 5 1.05 <0.005 278 4.4 13.3 <0.01 1.8 93.6 <0.01 26.1 450 7.7 OBS 2 Not sampled Not sampled <2 110 350 4 1.83 <0.005 299 9.6 25.4 <0.01 1.6 208 <0.01 60.7 890 7.8 PG_1 117 Not sampled <2 147 860 4 3.67 <0.005 351 32.8 59.1 <0.01 1.8 436 <0.01 164 1900 7.9 SCO_1 67 0 <2 141 270 3 2.05 2.6 540 16.9 29.8 4.7 <0.01 220 <0.01 99.5 1100 7.8 SCO_2 3 0 <2 116 220 3 1.42 2 366 9 20.5 0.55 <0.01 129 <0.01 70.1 770 7.5 SCO_3 137 0 <2 104 210 5 1.29 1.7 320 6.9 17.4 0.05 <0.01 125 <0.01 60.8 660 7.7

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