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Page 1 of 62
AQUIFER STORAGE AND RECOVERY
FUTURE DIRECTIONS FOR SOUTH AUSTRALIA
Russell Martin (DWLBC) & Peter Dillion (CSIRO)
Department of Water, Land and Biodiversity Conservation
CSIRO Land and Water
August 2002
Report DWLBC 2002/04
© Department of Water, Land and Biodiversity Conservation
This report was first published October 2001, Department for Water Resources
Page 2 of 62
Executive Summary
Aquifer Storage and Recovery (ASR) has considerable potential to improve the
quality and availability of water resources in South Australia by harvesting waters
such as, urban stormwater runoff and treated wastewater, and injecting them into
suitable aquifers for later recovery and use.
The South Australian Department for Water Resources has carried out a significant
number of investigations into ASR schemes using source water of varying quality.
The work is at the International leading edge in the design and implementation of
ASR schemes that use low quality waters injected into, and stored in, aquifers of low
transmissivity.
This paper reviews the status of ASR in South Australia, describes the experiences
to date, highlights emerging issues and looks at some of the future potential for ASR.
In South Australia, because the most suitable host aquifers for the storage and
recovery of large quantities of water are the deep confined Tertiary aquifer systems,
recharge wells have been the main method employed. This is the most difficult and
expensive method of recharge enhancement because if source water is not
adequately treated, clogging can quickly render the well inoperable. The method can
involve both single wells for injection and recovery or individual injection and
recovery wells.
Infiltration basins are another method in which water is collected in carefully
constructed holding ponds and allowed to infiltrate through the base of the ponds to
shallow water table aquifers. Bank filtration is the third method. In this process
pumping wells adjacent to the watercourse are used to induce water movement to
the groundwater store via the beds and banks of the stream. The method has limited
application in SA because of the ephemeral nature of many of our creeks and the
shortage of shallow aquifer systems adjacent to those water bodies carrying regular
and adequate supplies of water.
In the Adelaide metropolitan area, the redirection of large amounts of stormwater
runoff into a shallow aquifer system to limit discharge into the sea can quickly add up
and can result in rising water tables and infrastructure damage through water
logging. The prime targets for large scale ASR in the metropolitan area are therefore
the deeper confined aquifers where increasing pressures will not cause water table
elevation. Deep injection wells and filtration equipment can be relatively unobtrusive,
and opportunities may exist to use existing infrastructure to distribute the captured
runoff.
Within rural catchments, pollution of the aquifer is a major constraint to the
successful implementation of an ASR scheme. On-going water sampling and
analysis is critical in rural areas where some users rely solely on groundwater for
potable use. In both urban and rural situations confined aquifer systems allow the
best management of injected water.
Fractured rock aquifers, like the deep, confined sedimentary aquifers, offer good
sites for the injection of stormwater. There are sites that have been operating in SA
for a number of years, principally using gravity recharge. The storage capacity is
relatively small and the fracture networks can be connected over very large
distances. Injected water can move over these distances in a very short time also.
Remediation of contamination is difficult and injection into fractured rock aquifers
should be confined to storm water or creek runoff.
Page 3 of 62
A significant number of ASR schemes are now established or under establishment in
Adelaide metropolitan, regional and country areas. Within the next seven years ASR
schemes currently under development or investigation will be capturing, storing and
reusing in excess of 20 GL of stormwater or treated reclaimed water. Opportunities
exist to triple this volume under the management framework outlined in the integrated
water strategy currently being developed by DWR.
Recent ASR focus in SA has been on the Bolivar Wastewater Treatment Plant. A
consortium involving United Water, SA Water, CSIRO, the Department for Water
Resources (DWR) and the Department for Administrative and Information Services
(DAIS) are undertaking a joint study into the feasibility of injecting winter-excess
treatment water into the highly-stressed confined aquifer beneath the Northern
Adelaide Plains region.
Where aquifers are favourable, ASR offers a potentially low-cost method of storing
water as an alternative to surface storage. As a potable water supply option, per unit
volume of water, it is about half the cost of other water supply alternatives. In country
regions, and in arid and semi-arid environments, ASR can compete even more
favourably. Expansion of water supply capacity in these locations could be more
economic using ASR and utilising surplus pipeline capacities in winter.
The first Australian guidelines on the quality of stormwater and reclaimed water for
injection into aquifers, and for subsequent recovery and reuse, were produced in SA
in 1996. These were the outcome from a two-year Urban Water Research
Association of Australia study and were an international first. The guidelines
contained specific recommendations relating to licensing, pre-treatment, monitoring,
maximum concentrations of contaminants in the injected water and minimum
residence time.
A number of potential issues that will impact on ASR management and technology
have now been identified and are discussed in this paper. Other issues relate to use
of reclaimed water, licensing of ASR schemes, reporting and monitoring of existing
projects, accreditation of operators and installers, mapping of ASR potential, energy
cost relationships, aquifer storage capacity evaluation and aquifer rehabilitation.
The paper’s consideration of these issues has lead to recommendations that are in
favour of –
• Streamlining the ASR approval process with coordination by the Department
for Water Resources within the integrated water strategy framework
• annual monitoring reports by scheme operators and the establishment of a
public data base
• The accreditation of ASR installers and operators
• A technical and economic evaluation of potential ASR sites across the State
• A continued public sector role in ASR pilot projects and research which
coincides with the objectives of the integrated water strategy
• The early finalisation of technical and administrative guidelines
• A comprehensive education program for ASR owners and operators.
Page 4 of 62
CONTENTS
Page
Executive Summary 2
Abstract 7
1. INTRODUCTION 8
2. WHAT ARE AQUIFER RECHARGE ENHANCEMENT AND ASR? 10
2.1. Types of recharge enhancement 11
2.1.1. Recharge wells 12
2.1.2. Infiltration basins 13
2.1.3. Bank filtration 14
2.2 ASR applications 14
3. AUSTRALIAN HISTORY OF WATER BANKING 15
3.1. ASR in South Australia 15
3.2. ASR with reclaimed water 20
3.3. Potential for ASR in South Australia 22
4. ASR ISSUES 24
4.1. Issues associated with aquifer types in South Australia 29
4.1.1. Unconfined aquifers 29
4.1.2. Confined aquifers 29
4.1.3. Fractured rock aquifers 30
4.2. Regulatory Issues 31
4.3. Lessons from ASR Failures 32
5. RESEARCH 34
5.1 Outcomes of Australian ASR research 34
5.2 Current research 35
5.3 Future directions for research and applications 36
6. SUMMARY OF COSTS AND BENEFITS TO SOUTH AUSTRALIA 37
7. ASR GUIDELINES AND REGULATIONS 41
7.1. Water quality guidelines for ASR, 1996 41
7.1.1. Specific guidelines 42
7.1.2. Operation of ASR sites 45
7.2. Draft SA guidelines for stormwater ASR 47
7.3. Proposed SA guidelines for domestic scale stormwater ASR
in unconfined or semi-confined aquifers 52
8. POTENTIAL ISSUES AND OPPORTUNITIES 55
8.1. Domestic scale rainwater/stormwater ASR 55
8.2. Reclaimed water ASR 55
8.3. Licensing of new ASR projects 55
8.4. Monitoring and reporting of existing projects 56
8.5. Accreditation of ASR installers and operators 56
8.6. Maintenance of Government technical expertise in ASR 56
8.7. Mapping of ASR potential 56
8.8. Energy and water 56
8.9. Storage capacity evaluation 57
8.10. Aquifer rehabilitation 57
8.11. Communications 57
Page 5 of 62
9. RECOMMENDATIONS 58
9.1. Licensing procedures to be streamlined 58
9.2. Monitoring and reporting of ASR projects 58
9.3. Accreditation of ASR installers and operators 58
9.4. Mapping ASR potential in SA 58
9.5. Continued public sector investment in innovation in ASR pilot
projects 58
9.6. Guidelines 59
9.7. Education 59
10. CONCLUSIONS 59
11. ACKNOWLEDGEMENTS 60
12. REFERENCES 61
Page 6 of 62
List of Figures Page
Figure 1. Location of ASR sites around South Australia 9
Figure 2. Schematic depiction of ASR. Stormwater or reclaimed water
is recharged during the wet season and recovered in the dry
season. 10
Figure 3. Types of groundwater recharge enhancement (a) ASR,
(b) separate injection and recovery wells, (c) infiltration basins,
and (d) bank infiltration. 11
Figure 4. Bolivar ASR trial site and monitoring well configuration for the
confined Tertiary limestone target aquifer (T2). 21
Figure 5. Twin strategies for managing over-exploited aquifers 31
Figure 6. Flow chart showing the feasibility of artificial recharge with
stormwater and reclaimed water. 47
Figure 7. Multiple barriers to protect groundwater and recovered water
at ASR projects. 50
Figure 8. Components of a well-configured ASR system showing
barriers to pollution. 51
List of Tables
Table 1. The advantages and disadvantages of using wells for recharge
enhancement to aquifer systems. 12
Table 2. Advantages and disadvantages of using infiltration basins for
recharge enhancement to aquifer systems. 13
Table 3. Applications of ASR for water resource management. 14
Table 4. Operational ASR sites in South Australia. 17
Table 5. ASR Investigation sites in South Australia. 19
Table 6. Groundwater provinces of South Australia and the potential for
enhanced recharge. 23
Table 7. Potential changes in recharge post urbanisation. 25
Table 8. Issues associated with source water and source water quality. 27
Table 9. Water Resource and Water Use in South Australia and in
Adelaide and the Mount Lofty Ranges 37
Table 10. Comparison of estimated costs for domestic and municipal
scale ASR schemes. 39
Page 7 of 62
AQUIFER STORAGE AND RECOVERY: - Future Directions for South Australia
Abstract
Aquifer Storage and Recovery (ASR) has the potential to utilise surface water
resources, including urban stormwater runoff and treated wastewater that is largely
wasted; thereby relieving the pressure on groundwater resources. In the broader
sense, opportunities exist to use ASR to rethink our traditional water management
and distribution policies, and to provide cost-effective and innovative alternatives to
current methods of water supply. In South Australia, an increasing amount of stress
is being placed on surface and groundwater resources to meet demands from
expanding irrigated horticultural areas and urban populations. ASR can be used to
reduce some of the pressure on traditional supplies of water, especially in
metropolitan areas. But the sources of water for ASR must be carefully considered
especially in rural areas so as not to shift the burden from one water supply source to
another. A number of issues surround the use of ASR as a water management
solution and these relate principally to water quality and water quantity. In rural
areas, for example, the ‘harvesting’ of water from creeks and streams may result in
extra pressure on an already stressed resource by further reducing the amount of
water available to the environment. In urban areas the expanse of paved surfaces
provides an ideal medium to capture large volumes of stormwater runoff. However,
the volumes are often well in excess of any potential local demand. Understanding
ASR technology ensures success in almost all situations, whereas failure to
understand the unique aspects and complexities of implementing and managing an
ASR system will result in failure and lost investment. Over the past decade a
significant number of investigations into ASR have been undertaken by the
Department for Water Resources in partnership with CSIRO, local councils and
industry gaining extensive experience in both the implementation and management
of ASR schemes using source waters of varying quality. The main objective behind
the investigations into ASR have been to demonstrate that the process is technically
feasible and to address the associated management issues that accompany
enhanced recharge techniques. The experience gained places South Australia as a
world leader in the design and implementation of ASR schemes using low quality
waters injected and stored in low transmissivity aquifers. This report reviews the
status of ASR in South Australia, describes some of the successes and failures
experienced to date, highlights emerging issues and examines the future potential for
ASR.
Page 8 of 62
1. INTRODUCTION
The need to conserve, reuse and recycle water is becoming increasingly important
for both environmental and economic reasons. Water availability and demand are
both subject to seasonal variation, this results generally in a surplus of water
availability during peak winter rainfall periods and a shortage during the dry summer
months. Throughout the world various methods of recharge enhancement are
employed to meet the growing demand for safe potable water supplies.
The Department for Water Resources (DWR) in collaboration with the CSIRO Centre
for Groundwater Studies (CGS), and other partner organisations including SA Water,
United Water, local councils, catchment water management boards and industry are
involved in developing ASR technology in South Australia. ASR has been conducted
extensively throughout the world and other parts of Australia, but the practice in
these localities is generally restricted to spreading basin recharge to unconfined
aquifers.
The current research and development being undertaken by DWR and partner
organisations, where low quality water is being stored in deep confined aquifers of
low hydraulic conductivity, is world leading in the application of ASR technology.
In recent years, trials have examined stormwater ASR applications in the Adelaide
metropolitan area at Andrews Farm, The Paddocks, Greenfields Wetlands, Regent
Gardens, Scotch College and Mawson Lakes (Figure 1). Proponents have included
developers, local government, and the Major Projects Group from within the SA
Department for Administrative and Information Services (DAIS). Different aquifer
systems have been targeted including fractured rock, Tertiary limestone and
Quaternary sands. Different scales of application, ranging from small schemes to
meet localised demands to larger schemes that address more regional groundwater
issues, have been undertaken.
Applications being trialed outside the metropolitan area include the McLaren Vale
irrigation area, Barossa Valley, Northern Spencer Gulf (Spencer Regions Economic
Development Board) and the Clayton Water Supply (SA Water). Trials involving the
storage and subsequent recovery of treated wastewater are currently being
undertaken at Bolivar on the Northern Adelaide Plains and in the McLaren Vale area
(Figure 1).
ASR using treated wastewater presents an exciting opportunity to use the available
water resources more efficiently. It has the added advantage of providing a continual
supply, unlike stormwater, or harvesting from creeks and streams, which depends
upon rainfall.
One of the key drivers to the rapid acceptance of ASR in South Australia has been
the distinction by regulatory authorities concerning requirements for maintaining
water quality. A second key driver is that, where aquifers are favourable, ASR offers
a potentially low cost method of storing water as an alternative to surface storage.
Page 9 of 62
Figure 1. ASR Locations throughout South Australia
#
Yankalilla
Victor
Harbor
Gawler
Strathalbyn
Mount Barker
Birdwood
Cape Jervis
020
KILOMETRES
Nuriootpa
ANDREW'S
FARM
Barossa
Val le y
Magazine
Creek
PADDOCKS
Greenfields
South
Parklands
Morphetville
Racecourse
Cheltenham Racecourse
Parafield Airport
Northpark
UrrbraeTorrens Valley
Sports field
CLAYTON
ASR sites
Operational
Proposed
Trial
ADELAIDE
NORTHFIELD
99-0478
The Levels
Bolivar
Lake
A
lexandrina
ST VINCENT
BASIN
WILLUNGA
BASIN
MURRAY
BASIN
MOUNTLOFTYRANGES
Page 10 of 62
2. WHAT ARE AQUIFER RECHARGE ENHANCEMENT AND
ASR?
Recharge enhancement is defined by Freeze and Cherry (1979) as “Any process by
which man fosters the transfer of surface water into the groundwater system”. A more
detailed definition is given by Asano (1985) as “augmenting the natural movement of
surface water into underground formations by some method of construction, surface
spreading of water in basins, or artificially changing natural conditions, such as by
stream channel modification.” Among the methods for recharge enhancement, is the
use of wells to inject water into aquifers.
The term ASR is attributed to Pyne (1995): “Aquifer Storage and Recovery may be
defined as the storage of water in a suitable aquifer through a well during times when
water is available, and recovery of the water from the same well during times when it
is needed”.
ASR can be used as a resource management tool where water from a source is
treated and then stored underground (Figure 2). Large volumes of water may be
stored underground thereby reducing the need to construct expensive surface
reservoirs. ASR can also have added benefits in aquifers that have experienced
long-term declines in water levels as a result of concentrated and heavy pumping.
Groundwater levels can be restored if sufficient quantities of water are recharged eg
the confined aquifers beneath the Northern Adelaide Plains.
Figure 2. Schematic depiction of ASR. Stormwater or reclaimed water is
recharged during the wet season and recovered in the dry season.
(after Dillon et al, 2000)
Confining Layer Natural
Recharge
Wetland/Basin
Stormwater and/or
Wastewater
Groundwater Level
Sewage
Sewage
Treatment
Irrigation Injection
Well
Aquifer
Recovery from aquifer in dry season
Storm/Waste-water to aquifer in wet season
W
e
t
S
e
a
s
o
n
D
r
y
S
e
a
s
o
n
GRAPHICS BY CSIRO LAND & WATER
Aquifer Storage and Recovery (ASR)
Page 11 of 62
2.1. Types of recharge enhancement
There are a number of methods whereby the natural recharge processes can be
accelerated and collectively are referred to as recharge enhancement or artificial
recharge. ASR relates specifically to enhanced recharge using a well and is typically
associated with deeper confined aquifer systems (Figure 3(a)). Individual injection
and recovery wells (Figure 3(b)) can be used where groundwater quality is fit for
intended use and the distance separating the wells provides opportunities for
attenuation of contaminants. Infiltration basins are another method whereby water is
collected in carefully constructed holding ponds and allowed to infiltrate through the
base of the ponds to shallow water table aquifers (Figure 3(c)). Bank filtration is a
third method whereby pumping wells adjacent to a watercourse are used to draw
water from a stream into the aquifer (Figure 3(d)).
Figure 3. Types of groundwater recharge enhancement (a) ASR, (b) separate
injection and recovery wells, (c) infiltration basins, and (d) bank
filtration
Methods for groundwater recharge enhancement
Methods for groundwater recharge enhancement
(a) ASR - single well
(b) injection and recovery - multiple wells
(c) pond infiltration,
soil aquifer treatment
(d) induced infiltration
Page 12 of 62
2.1.1. Recharge wells
Recharge wells are typically the most difficult and expensive method of recharge
enhancement because if the source water is not adequately treated clogging will
quickly render the well inoperable. Recharge wells are used where the shallow
lithology does not possess characteristics suitable for aquifer storage and recovery
such as, low transmissivity or where land has such a high value that above ground
storage ponds are not economically viable. On-going management and maintenance
costs associated with the operation of recharge wells are also the highest of the
possible recharge methods. Appropriate well construction coupled with careful
management is required to ensure that the maximum life (up to 20 years) can be
obtained for the recharge well. If any one of these aspects is ignored and the
operator neglects to manage the system appropriately, failure of the ASR scheme will
result or alternatively expensive remediation of the injection well will be necessary.
In South Australia, because the most suitable host aquifers for the storage and
recovery of large quantities of water are the deep confined Tertiary aquifer systems,
recharge wells have been the main method employed. Table 1 presents a summary
of some of the advantages and risks of using an injection well as a method of
introducing the captured water to the aquifer.
Table 1. The advantages and disadvantages of using wells for recharge
enhancement to aquifer systems
Recharge enhancement to deep aquifers using wells
Advantages Disadvantages
Injection and recovery rates can be
mechanically controlled to ensure desired
rates are obtained
Relatively small space required for installation
of well
Recovery efficiency (the volume of injected
water that meets the enduse requirements) is
typically greater than 50% on first injection
and recovery cycle for sedimentary aquifers
Recovery efficiency improves with successive
injection cycles
Treatment works can be some distance from
injection wells
Opportunities to use existing infrastructure to
redistribute water
Opportunities to use existing infrastructure to
deliver treated water to injection sites
In sedimentary aquifers the injected water
remains in close proximity around the well
making it easy to clean up in the event of
contamination.
Variety of methods of treatment for the source
water.
Only economic method of accessing confined
aquifers.
Clogging of aquifer matrix or screens from
either fine particulate matter or from
microbiological activity
Large surface storages may be required to
capture source water from creeks or
stormwater if recharge rates are slow.
Recovery efficiency can be as low as 10%
from fractured rocks.
Geochemical interactions between rock and
injected water may affect quality of recovered
water.
Well collapse through dissolution of aquifer
matrix.
Over-pressure may result in failure of the
confining bed separating aquifers.
On recovery, continual production of fine
aquifer material causing pumps to seize.
Well failure after only a few years of operation
requiring new replacement wells to be drilled.
Potential changes in contaminate loads if
source water is from urban or rural catchment
runoff.
In a fractured rock aquifer little control on
direction and distance injected water may
travel.
Backwash waters need to be discharged.
Page 13 of 62
2.1.2. Infiltration basins
Infiltration basins are typically used where there is sufficient depth of sediment
between the base of the infiltration pond and the underlying watertable and there are
no low permeability layers. Infiltration occurs through the base of the pond with the
infiltration driving force controlled by the depth of water in the pond. Infiltration basins
are employed where the water source to be captured is stormwater runoff and there
is sufficient room to establish the basins, often alongside the watercourse. Recovery
of the stored water from these systems is generally via shallow collector wells. Table
2 presents some of the advantages and disadvantages of using infiltration basins as
a means of recharge enhancement to aquifer systems.
There are limited opportunities to establish large-scale infiltration basins within South
Australia generally because there is insufficient depth of sediment between the base
of the pond and the shallow water table aquifer or the shallow lithology has low
permeability in the case of the Hindmarsh Clay across the Adelaide Plains. There are
some small-scale schemes operating in metropolitan Adelaide (eg. Brompton Estate
established by the University of South Australia (Argue 1997)). Some opportunities
may present themselves in the outback areas of South Australia to augment the
supplies of remote Aboriginal communities.
In the outback areas one of the issues that needs to be addressed is the design and
maintenance of surface capture structures to withstand the extreme events that
typically occur. If the basins are not designed properly they are likely to wash away in
the first flood event requiring expensive rebuilding. A second issue that would need
to be addressed is that high evaporation rates are likely to result in rapid changes in
the quality of the water held in the storage dams unless the dams are covered to
reduce the evaporation that will occur while the water infiltrates to the underlying
aquifer.
Table 2. Advantages and disadvantages of using infiltration basins for recharge
enhancement to aquifer systems
Recharge enhancement using infiltration basins
Advantages Disadvantages
Can be relatively low maintenance
Simple and effective system
Improved water quality
May reduce the need for treatment of
recovered water.
Increased hydraulic gradients leading away
from beneath the infiltration basin that may
result in greater discharge to surface water
bodies.
Maximised recharge rates
Requires periodic drying out and scraping to
maintain infiltration efficiency
Large areas required for construction of
infiltration basins
Water may be subject to reinfection from
birds/animals
May require chemical additives to control
algae growth
Some loss of supply to evaporation
Expensive to construct above ground storage
appropriate for the conditions
If water table not deep enough below ground
surface water logging may result
Can increase discharge to surface water
bodies
Page 14 of 62
2.1.3. Bank filtration
Bank filtration is the acceleration of the naturally occurring influx of surface water to
the groundwater store, via the bed and banks of the surface water body, induced by
pumping. This process is often used to obtain a general improvement in water
quality. Induced bank filtration schemes are exploited mainly in Europe and USA.
Bank filtration has advantages over surface water extraction allowing -
Removal of particles, bacteria, viruses and parasites,
removal of easily biodegradable compounds, including algal toxins,
reduction of persistent organic contaminants and heavy metals; and
attenuation of demand and supply concentration peaks.
In addition, bank filtration can provide an effective pre-treatment step through use of
natural processes to ensure sustainability of supply and the provision of uniform
quality raw feed water to enable treatment process optimisation.
There are limited applications of bank filtration in South Australia because many of
the creeks are ephemeral. Very few locations have sufficiently well developed
shallow aquifer systems adjacent to large water bodies to enable adequate quantities
of water to be drawn into the aquifer system to meet large demands. Many alluvial
aquifers, including those adjacent to the River Murray, are saline, preventing bank
filtration for potable supplies. Some isolated opportunities may present themselves at
Paringa (Dillon et al. 2000) where banks have been flushed.
2.2. ASR applications
ASR has gained acceptance as a water resource management tool because of the
wide variety of applications to which it may be applied. ASR may be used to address
issues relating to water storage, water quality and environmental and operational
needs. These are broken down into the broad categories illustrated in Table 3.
Table 3. Applications of ASR for water resource management
Water Storage Water Quality Environmental
Operational
Seasonal storage and
recovery
Pathogen reduction Restoration of
groundwater levels
Maintenance of
distribution system
pressure and flow
Long-term storage Chlorination byproduct
removal
Reduce/prevent saline
intrusion
Deferment of the
expansion of treatment
facilities
Emergency storage Stabilisation of
aggressive water
Reduction of land
subsidence
Deferment of the
development of new
water sources
Diurnal storage Control of contaminant
plumes
Enhancement of
baseflow to streams
Balancing peak
seasonal demands
Reclaimed water for
reuse
Reduction of nutrient
rich discharge to
marine environment
Enhance wellfield
production
(adapted from Pyne 1995)
Page 15 of 62
3. AUSTRALIAN HISTORY OF WATER BANKING
The first known and largest Australian water banking projects were established in the
1970's in the Burdekin Delta near Townsville, Queensland. Groundwater levels in
the delta were in decline because extraction for irrigation of sugar cane had
increased and exceeded the natural replenishment of the aquifers from rainfall
recharge and from flows in the Burdekin River. Two main recharge projects divert
large quantities of river water into seepage trenches, constructed in sandy deposits
with high permeability. Intermittently the ponds are allowed to empty and the
accumulated layer of silt and algae are removed.
A similar style of recharge trial but at a much smaller scale was conducted at
Geelong in the late 1980's to help store surface water in a semi-confined aquifer. A
thin layer of silt several metres below the base of the basin impeded infiltration rates
and a trench was dug to perforate this layer and increase recharge to the underlying
aquifer. This trial was discontinued presumably because the volume of recharge did
not justify the cost of operation.
Another recharge system was established in South Australia in 1979 to ensure
continuation of groundwater recharge to the aquifers of the Northern Adelaide Plains
from the Little Para River following construction of a water supply dam upstream.
Approximately 1800 ML of water is released annually from storage according to a
release schedule designed to maintain annual recharge at its mean annual rate. At
around this time the Ophir Dam was built in the north west of Western Australia to
provide water supplies for mining. Water was released from the dam into infiltration
ponds downstream to increase groundwater recharge and protect water from
evaporation. It is understood that this system is no longer operating. Attempts to
increase recharge from the Lockyer and Callide Valleys in Queensland in the 1970's
by constructing weirs to hold surface water longer and raise the driving head in the
streambeds were regarded as failures, due to silt accumulation reducing active
storage and lowering the streambed hydraulic conductivity and infiltration rate.
For more than a century stormwater has been introduced into aquifers via pits and
sumps in Perth, Western Australia and via drainage wells at Mount Gambier in South
Australia. Recharge was initially incidental to stormwater disposal for flood control
but consequences on groundwater quality have been taken into account from the
1970's as appreciation of the potential for pollution has increased. In the Angas-
Bremer area of the southern Mount Lofty Ranges in South Australia the first
intentional recharge via wells commenced in the 1980's. An expansion of viticulture
and deteriorating groundwater quality and yields in irrigation wells resulted in some
farmers diverting fresh winter stream flow into their wells to improve yields and
reduce salinity in the following summer.
3.1. ASR in South Australia
In South Australia, surface and groundwater resources are increasingly being
stressed to meet the demands of expanding irrigated horticulture and urban
populations. The availability of adequate water supplies is crucial to the future
development of most regions in South Australia.
In many areas of the State, reticulation systems are operating at or near full capacity
during peak demand periods. A continued sole reliance on current sources would
raise the prospect of an expensive duplication or augmentation of supply capacity to
meet growing demand. Potential alternative sources of second class water supplies
Page 16 of 62
such as urban stormwater runoff and reclaimed water (from sewerage treatment
plants or industrial effluent) are largely ignored in many areas and could be used to
reduce current demands on potable supplies from external sources.
Since the early 1990’s Aquifer Storage and Recovery (ASR) has been
increasingly used in South Australia to address specific surface or groundwater
problems that have needed innovative solutions.
The schemes implemented range from harvesting catchment runoff in urban
areas to providing safe potable rural water supplies.
Many of the schemes thus far implemented cover a variety of scales from
mitigating catchment runoff in urban areas and provision of safe potable water
supplies, to meeting the demands of large irrigation schemes.
In metropolitan Adelaide annually around 200 000 ML (ML) of stormwater runoff from
paved surfaces is discharged via a network of drains. Up until recently around 100
000 ML of secondary treated wastewater was discharged annually to the sea from
the various wastewater treatment plants.
In recent years, trials by the Department for Water Resources, in cooperation with
local councils (notably Salisbury), CSIRO, and other partners have examined, ASR
applications at a number of sites throughout the metropolitan area. These sites
include The Paddocks, Andrews Farm, Greenfields Wetlands, Regent Gardens and
Kaurna Park which collectively capture and store (when last evaluated) around 680
ML of stormwater runoff per year (Table 4). This figure is reported to have increased
to 1000 ML per year (pers. com. C Pitman, City of Salisbury). Treatment prior to
storage in the aquifer is typically via wetlands.
The potential performance of wetlands as key components of an ASR scheme for
urban water was first investigated at The Paddocks (Thomlinson et al, 1993). The
first ASR schemes specifically designed to capture urban stormwater from specially
constructed wetlands were established at Andrews Farm and Regency Gardens.
These systems have been closely monitored and reported on in several publications.
They are listed with other national and international references on similar schemes in
Pavelic and Dillon 1997.
The Urban Water Resources Centre based at the University of South Australia has
focussed on the development of trench systems to undertake a similar role to that of
wetlands in pollution reduction, flood mitigation and water capture. Schemes have
been established and monitored at Brompton Housing Estate and Parfitt Gardens
(Argue, 1997).
Page 17 of 62
Table 4. Operational ASR sites in South Australia
SITE
(year
commenced)
AQUIFER SOURCE
WATER
TYPICAL
RECHARGE
(ML per year)
Mt Gambier
(late 1800’s)
Tertiary Limestone Stormwater 2,800
Angus Bremer
(mid 1970’s)
Tertiary Limestone Bremer River 1,000
Scotch College
(1989)
Fractured rock Brownhill Creek 40
Regent Gardens Tertiary Limestone Urban runoff 60
Andrew’s Farm
(1993)
Tertiary Limestone Urban runoff
Wetland prefilter 150
The Paddocks
(1995)
Tertiary Limestone Urban runoff
Wetland prefilter 120
Willunga Basin
(various)
Tertiary Limestone Creek stormwater flow Approx 70
Greenfields
(1995)
Tertiary Limestone Stormwater
Wetland prefilter 100
Kaurna Park
Tertiary Limestone Stormwater
Wetland prefilter 100
Northgate
(2001) Tertiary Limestone Urban runoff 110
TOTAL Adelaide Metro
State
680
4000*
Note:
* Assumes only 500 ML per year is currently stored in the aquifer via enhanced recharge in
Angus Bremer region.
Increasing numbers of ASR schemes are now being established in Adelaide and
other urban areas. The success of all the schemes indicates that the technique has
wide application in many different hydrogeologic regimes in South Australia. A further
eleven sites are currently under investigation within the metropolitan area with an
additional 12 proposed investigation sites. Collectively, these additional sites could
capture and store up to an additional 3000 ML of stormwater runoff (pers. com. C
Pitman, City of Salisbury) (Table 5). A summary of the aims for each of the ASR sites
follows
• Mount Gambier: Mount Gambier, a city of 23,000 people in the south-east of the
State, disposes of all stormwater via a network of drainage wells into an
underlying karstic aquifer. This water is subsequently withdrawn for use as a
potable water supply.
Page 18 of 62
• Scotch College: A small ASR scheme harvesting approximately 10 ML of water
from an adjacent creek, and recharging a fractured hardrock aquifer is in use at
the College. The stored water is used to irrigate adjacent ovals during the
summer months.
• Andrews Farm: Andrews Farm, on the Northern Adelaide Plains, was a project
undertaken in conjunction with a private housing developer and local government
to manage urban stormwater. Flood detention ponds are used to provide
temporary storage of the urban runoff and to filter the water prior to injection into
the confined aquifer. Results indicate that the aquifer is capable of storing
injected water and the brackish native groundwater has been significantly
freshened to a level suitable for irrigation. Quantities recharged between 1993
and 1996 ranged from 18 to 100 ML depending on winter rainfall.
Regent Gardens: At Regent Gardens, ASR was designed and constructed as
part of a medium density urban infill development. The capacity of the existing
stormwater system necessitated the inclusion of a flood control basin within the
development to attenuate peak flows. Stormwater is retained in a system of
wetland detention basins and recharge is via gravity infiltration through a 150mm
diameter, 80m deep well completed in a saline, fractured hardrock aquifer.
Annual recharge volumes are in the order of 40 ML per year from winter flows
and the site has been operational since 1994.
• Clayton: At Clayton, on the western shore of Lake Alexandrina, the town water
supply has been traditionally pumped from the lake. In recent summers this
supply has been under threat from toxic algal blooms caused by high nutrient
loads in the River Murray. An ASR project was undertaken to inject high quality
potable water, when available, from the lake into an unconfined, high salinity
(>40,000 mg/L) limestone aquifer. This unique situation required the
development of a lens of potable water within a buffer zone of mixed saline and
fresh injected water. Testing confirmed that a lens of potable water was
successfully established creating a safe potable town water supply. This scheme
is now in its fourth year of operation.
• The Paddocks: The Salisbury Council wetland site known as The Paddocks was
developed with the long term goal of conjunctive wetland treatment and ASR of
stormwater using a confined limestone aquifer. Injection at this site was under
pressure due to the low hydraulic conductivities. Some 75 ML of stormwater
were injected during the winter of 1996, and a recovery trial produced an
equivalent amount of irrigation quality water. The site has been operational since
that time and routinely stores between 75 and 100 ML of water from an urban
catchment runoff with wetlands pre-treatment to reduce nutrient and pollution
loads prior to injection.
• Willunga Basin: In the Willunga basin, aquifer injection testing has been
undertaken as a result of interest shown in ASR by local irrigators and local
government. ASR is to be incorporated as part of the integrated catchment water
resources management of the basin. Three sites have been established to
harvest excess catchment runoff for injection and subsequent reuse for irrigation
of vines.
• Mawson Lakes: This is an infill urban development encompassing some 610
hectares and catering for a community of approximately 10,000 people. DWR
Page 19 of 62
carried out preliminary investigations into the feasibility of using ASR techniques
to manage stormwater and treated wastewater from the development. Further
development of this scheme is awaiting the outcomes of the Bolivar Trial.
• Greenfields Wetlands: This involves opportunistic harvesting of excess water for
irrigation and industrial uses from the wetlands and storage using ASR.
• Kaurna Park: A laser-levelled wetland was constructed at Kaurna Park and
receives stormwater for gravity or pressure injection into a Tertiary limestone
aquifer on the Northern Adelaide Plains.
• Clare Valley: The Clare Valley ASR project is assessing the feasibility of
harvesting excess streamflow and storing the water in a fractured hardrock
aquifer. The aim is to provide additional water supplies for the viticulture industry.
• Morambo Creek: At Morambo Creek the aim is to use ASR techniques to store
water in an aquifer that is under stress as a result of irrigation demands. Excess
winter flows will be captured and stored. An additional benefit is that this scheme
will also provide flood mitigation for land downstream that is subject to inundation
during severe flood events.
Table 5. ASR Investigation sites in South Australia
SITE
(year commenced)
AQUIFER SOURCE WATER
TYPICAL
RECHARGE
(ML per year)
Clare Valley
Fracture Rock Creeks approx 50
Bolivar
Tertiary Limestone Reclaimed water approx 10,000
Urrbrae
Unconsolidated
sands
Urban runoff
Wetland prefilter plus
rapid sand prefiltration
30
Parafield Airport
Tertiary Limestone Urban runoff
Wetland prefilter 1,500
Mawson Lakes
Tertiary Limestone Urban runoff & treated
wastewater approx 600
Morphettville
Racecourse
Tertiary Limestone Urban runoff
Wetlands prefilter approx 150
Willunga Basin
Tertiary Limestone Reclaimed water approx 4,000
Page 20 of 62
Other projects where ASR has been employed as a water resources management
tool include the Angas Bremer region.
New projects featuring ASR technologies applied in an urban area include; Coopers
Brewery, Parafield Airport, Cheltenham Racecourse, Morphettville Racecourse, Tea
Tree Gully, South Parklands and the reuse of reclaimed water from the Glenelg
Wastewater Treatment Plant.
3.2. ASR with reclaimed water
More recently the focus of ASR in South Australia has shifted to using treated
wastewater from the major treatment plants as this provides a constant source and
quality of water all year round. The storage of treated effluent in aquifers by direct
injection via bores has not been practiced widely. Where it has been trialed the level
of pre-treatment has been to near potable quality (Pavelic and Dillon, 1997).
The Bolivar Wastewater Treatment Plant (WWTP) produces approximately 50 000
ML of treated wastewater per year. Significant long term environmental impacts on
the mangrove forest and on sea grass beds have been observed as a consequence
of discharging secondary treated sewage effluent and stormwater to the marine and
estuarine environments along the South Australian coastline (Martin, 1998).
At the same time the horticultural industry in the nearby Virginia triangle is lacking
sufficient irrigation water to fully meet its needs.
A consortium comprising United Water, SA Water, CSIRO, DWR and Department of
Administration and Information Services (DAIS) have combined to undertake a joint
study into the feasibility of injecting the winter surplus of reclaimed water into the
confined aquifer beneath the Northern Adelaide Plains. A four year, $3 million
research project is currently underway to determine the technical feasibility,
environmental sustainability and economic viability of ASR using treated water from
the Bolivar WWTP. The project will demonstrate that any potential health risks
associated with the practice can be controlled effectively by a strict quality regulation
and monitoring regime.
It has been proposed that reclaimed water from Bolivar WWTP be used for irrigation
purposes in the Virginia/Two Wells region. However, the Bolivar WWTP produces
wastewater all the year around at a constant rate. With increased irrigation
development on suitable soils, the Virginia Pipeline Scheme (VPS) will account for
much of the summer flow, but a demand is needed for the winter production. Injection
of the reclaimed water into the highly stressed confined aquifer of the region provides
that opportunity.
The benefits to follow from the injection of water into the confined aquifer (Figure 4)
are that there will be an increase in groundwater hydraulic pressure. This increased
pressure in the aquifer will result in an improvement in the groundwater level
throughout most of the aquifer.
Page 21 of 62
Figure 4. Bolivar ASR trial site and monitoring well configuration for the
confined Tertiary limestone (T2) target aquifer (after Martin 2000)
The unique aspect and new technology associated with this project is that the water
is treated to a level that is suitable for unrestricted irrigation use and subsequent
ASR. This is unlike other localities where treatment is to a much higher standard
prior to ASR.
The project is structured to address the issue of a water quality less than drinking
standard that confronts the proponents when considering injection of this water. It is
recognised that reclaimed water differs significantly from stormwater in its nutrient
and microbiological content. Issues associated with reclaimed water - well bore
clogging, fate of pathogens and microbiota, interaction of chemical species with
aquifer matrix material and aquifer hydraulics - need to be evaluated.
In addition, the potential impacts of ASR on adjacent aquifers and on the pressures
and quality in wells of other groundwater users in the area, need careful assessment.
This work is currently being undertaken.
Aquifer storage and recovery is a key element in balancing seasonal supply and
demand for the treated water with outcomes from the project that are likely to
include-
additional water being available for the development of horticulture throughout the
region,
the availability of more water for irrigation with the potential to double the current
farm gate value of produce from $100 million to over $200 million,
maintenance of pressures within the aquifer system to maintain groundwater
levels and ensure that this resource does not become un-useable as a result of
intrusion from surrounding saline groundwaters and the sea,
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Page 22 of 62
transfer of the information gained at this site to other similar sites such as
McLaren Vale where treated water from the Christies Beach WWTP is being
used.
As the required level and cost of pre-treatment rises, the target area for sale of the
recycled effluent must shift towards urban users. They can substitute recycled
effluent for potable water for those uses requiring good quality water - but at a quality
and price less than that of potable water.
Table 4 presents a summary of the operational ASR sites within South Australia and
the quantities of water that are harvested annually. All of these sites have been
implemented by DWR in cooperation with either local councils or the private sector.
The current volumes captured, stored and reused are relatively small (approx 1 GL),
in comparison to the total amount of water that discharges to the Gulf St Vincent as
stormwater runoff (estimated to be 390 GL/year (State Water Plan 2000)), it should
be remembered that most of the operational constraints to undertaking ASR using
low quality surface waters injected into low hydraulic conductivity aquifers have only
been resolved in the past five years as a result of the Andrews Farm trial site. If all of
the current ASR investigation sites shown in Table 5 (inclusive of those using
reclaimed wastewater) are fully implemented, the quantities of water captured for
storage and subsequent reuse will approximate 20 GL within the next 10 years.
Rather than allowing ASR to develop independently by interested groups or
individuals, ASR forms the basis of the integrated water strategy framework for South
Australia, currently being developed by DWR. Under this framework ASR could
potentially increase the quantities of water available for reuse within the next 7 to 10
years by two fold over the projected 20 GL.
Trials are progressing at McLaren Vale using the reclaimed water from Christies
Beach WWTP. There is a requirement to undertake trials in this locality also because
the treatment processes used at Christies Beach treatment plant are significantly
different. The quality of water is considered to be Class C suitable only for application
by drip irrigation. The different treatment processes means that the water product
from Christies beach has a higher level of suspended particulate matter which has
required pre-filtration to prevent clogging and thus well failure. A number of different
filtration methods have been trialed to provide water of a suitable quality for injection.
3.3. Potential for ASR in South Australia
Table 6 identifies the major groundwater areas across South Australia and presents
an indicative summary of the potential of these regions to incorporate ASR as a
resource management tool based on the known aquifer types and the availability of
source water. As factors affecting the viability of ASR are site specific, it is
recommended that more detailed evaluation be undertaken accounting for geology,
aquifer suitability, source water quality and demands for water.
Page 23 of 62
Table 6. Groundwater provinces of South Australia and the potential for
enhanced recharge.
Region Aquifer Type Potential
Officer Basin Quaternary &
Fractured rock
Unconfined
Confined
Minor potential and sustainability of schemes
may be questionable as rainfall duration and
intensity highly variable. Only likely to occur on
small scale given limited number of users.
Limited opportunities
Great Artesian
Basin
Quaternary
Tertiary aquifers
Unconfined
Confined
Minor potential and sustainability of schemes
may be questionable as rainfall duration and
intensity highly variable. Only likely to occur on
small scale given limited number of users.
Occurs adjacent to WMC wellfield A to sustain
aquifer pressures near mound springs
Eucla Basin Quaternary Unconfined Minor potential but sustainability of schemes
may be questionable as rainfall duration and
intensity highly variable. Only likely to occur on
small scale given limited number of users.
Torrens Basin Tertiary aquifers Confined Limited opportunities
Pirie Basin Tertiary aquifers Confined Potential exists around some of the urban
centres however, underlying aquifers highly
saline. Some potential from offpeak mains and
treated wastewater. Further investigation
warranted.
Possibilities may also occur in outwash alluvium
along base of Flinders Ranges
Eyre Peninsula Quaternary Unconfined Limited potential for capturing surface water and
limited potential for storage of large quantities of
treated wastewater near major urban centre of
Port Lincoln
Yorke Peninsula Quaternary Unconfined Potential in a few locations where stormwater /
surface pipeline water is available.
Adelaide
Geosyncline
NAP
Metro
Adelaide
Barossa
Willunga
Fractured Rock
Tertiary aquifers
Shallow aquifers &
Tertiary aquifers
Gravel aquifers
Tertiary aquifers
Confined &
unconfined
sub-aquifer
systems
High potential although recovery efficiencies
likely to be low. Potential risk of reactivating
dormant springs.
High potential throughout the various St Vincent
sub-basins in both the confined and unconfined
aquifers. Water sources available include stream
catchment runoff (<15GL), treated wastewater
(approx 17GL) and urban catchment runoff
(approx 280GL)
Murray Basin Contains a variety of suitable aquifers and may
be an option for some of the larger communities
to treat and store wastewater.
Olary Arc Limited potential
Otway Basin Potential for treated wastewater and from some
of the creeks. Review of the stormwater
discharge around Mt Gambier required.
Page 24 of 62
4. ASR ISSUES
The main issues facing any proponent of ASR relate to source water quality and the
technical feasibility at the selected location. ASR systems will be feasible where
three key areas are adequately addressed:
i) hydrogeological and technical system design and operation to achieve
benefits that exceed costs.
ii) system compliance with regulations, within a progressive regulatory
regime
iii) establishment of suitable consultative mechanisms to allow satisfactory
stakeholder negotiations.
A feasible system must work within the constraints of -
availability of surface water of sufficient quantity and quality,
suitable lands for surface works required for surface water capture,
temporary storage, treatment, transfer to the ASR site, ASR headworks
and reticulation to the demand location,
a suitable aquifer for long term storage, additional quality modification and
transmission (as may be required),
a capital funding source for establishing the system and;
a contracted demand for the water product, adequate to ensure the
ongoing profitability of the system.
Issues associated with ASR in an urban setting generally revolve around constraints
on available storage or, if the water is of low quality, the need for additional
infrastructure to deliver the water to the demand centres.
One emerging issue relates to the mixed messages that the public is receiving
concerning the management of stormwater runoff. In a particular catchment area for
example, if a few individuals are redirecting their roof runoff into a shallow aquifer
system then there is likely to be a good outcome. However, as more people in the
catchment take up this practice to limit the amount of stormwater that is discharged
to the marine environment, the incremental volumes quickly add up to a significant
amount of water being directed to shallow aquifer systems resulting in rising water
tables and damage to existing infrastructure through waterlogging.
The problem is further compounded by the misconception that recharge rates to
natural groundwater systems under urban areas are substantially reduced as a result
of the increase in impervious surfaces. In actual fact, because of the importation of
reticulated water, and the practice of summer irrigation, the net recharge to
groundwater has increased under urbanisation (Martin, 1997; Learner, 1996).
Table 7 shows the potential impacts on the shallow aquifer system in both pre and
post urbanisation situations assuming recharge under natural vegetation conditions
(that is prior to urbanisation) may have been up to 5% of the total annual rainfall.
Redirection of stormwater roof runoff, and other sources, to the shallow aquifer
system, coupled with the summer irrigation from imported water, may have the
capacity to increase recharge up to five times that which occurred under pre-urban
conditions. In addition, urbanisation has altered the natural drainage courses that in
the past would have facilitated discharge from the shallow aquifers.
Page 25 of 62
Table 7. Potential changes in recharge post urbanisation
Assumptions
Pre- Urbanisation
Urbanisation
Area 100 sq km
Rainfall 800 mm
Recharge under natural vegetation 5% of precipitation 4000 ML 0 ML
Recharge under urbanisation (1) 8% of precipitation 6400 ML
Summer recharge (2) 1% of irrigation (estimate 300 mm
urban)
0 ML 300 ML
Enhanced recharge using ASR (3) 20% of precipitation 0 ML 16 000 ML
TOTAL 4000 ML 22 700 ML
Note: Theoretical values used for the purpose of illustration
1. Recharge under urbanisation increased as a result of removal of vegetation cover
2. Recharge increased during summer as a result of irrigation
3. Assumes capture and storage of only 20% of available runoff
There are a number of sites across metropolitan Adelaide where waterlogging and
flooding of cellars is becoming more prevalent especially if above average rainfall
occurs during winter. Consequently, the primary targets for large scale ASR in the
metropolitan area are the deeper confined aquifers where increasing pressures do
not affect water table elevation.
Provided a balance is maintained between the water that is captured and stored and
subsequently withdrawn to meet a sustained demand, many of the above issues can
be managed. ASR within an urban environment can clearly play a significant role in
re-using water that otherwise may be lost as discharge to the marine environment. It
can also reduce demands on existing supplies.
ASR schemes situated in either urban or rural areas have the capacity to capture
large quantities of surface water because the dams can be filled and emptied multiple
times during a season. This has potential to shift pressure from groundwater
resources onto surface water resources, thus reducing flows required to sustain
environmental needs.
Pollution of the aquifer is also one of the major constraints to the successful
implementation of an ASR scheme within a rural catchment. Proponents should be
aware of the on-going management costs and risks associated with the practice.
1) On-going water sampling and analysis will be required up to three or four times
per year at each location. The types of analyses required could cost in excess
of $1200 per sample and depend on a risk assessment based on pesticide use
within the catchment and on the nature of other contaminants and nutrients that
could impair water quality.
On-going sampling is critical in rural areas where there are users who rely solely on
the groundwater for potable use. Another reason for very regular sampling is that
landuse within a catchment can change very rapidly resulting in changes in the types
and concentrations of pesticides/herbicides and other potential contaminants being
applied across the catchment. Different concentration levels of pesticides and
herbicides may be mobilised from within the catchment depending on rainfall duration
and intensity.
In urban areas contaminants also include organic compounds that may be extremely
difficult to remove from an aquifer. Consequently, the sampling suite is considerably
more diverse and more expensive.
Page 26 of 62
2) Water recovered after injection needs to be assessed to determine its suitability
for its intended use.
Water rich in oxygen, coming into contact with various minerals in the aquifer matrix
may result in deterioration as well as improvements in its quality. It is therefore
advisable to undertake detailed mineral analysis of the aquifer matrix material before
undertaking ASR and even then there are no certainties as the sample analysed is
only representative of a very small section of the entire aquifer. As an example,
release of arsenic or production of hydrogen sulphide can occur.
3) Careful management may be required to ensure the well will continue to accept
the same quantity of water each year or during each subsequent injection
cycle. Clogging or partial well collapse can cause reduced injection rates.
Inadequate filtration of the source water, incorrect completion of the well and a
number of other factors will result in the well failing. A monitoring well will assist to
evaluate clogging and the effectiveness of unclogging methods.
Like a filter, the well will also require some periodic backwashing throughout the
injection phase and a good practice is to do this every three to five days during
injection for an hour or two at the maximum pumping capacity. The water recovered
from the well can be discharged back into the storage dam and allowed to settle out
any solids before reinjection.
In some areas despite all the best intentions and the adoption of best practice for
ASR, replacement injection wells may be required every five to ten years. In most
cases however, injection wells should last longer than ten years if optimum operating
practices are adopted.
Table 8 summarises some of the considerations that must be addressed in relation to
possible impacts of source water quality on the successful implementation of ASR.
The setting, either urban or rural, may also pose some constraints on the successful
implementation of ASR.
Page 27 of 62
Table 8. Issues associated with source water and source water quality
Water
Source
Issues
Creeks & rivers Urban stormwater Reclaimed water
Contaminants Large range of
contaminants
Diffuse sources
Rapid changes in
types of contaminant
associated with rapid
landuse changes in
catchment
Typically rural source
waters may have
elevated nitrogen,
phosphorus and
ammonia compared to
groundwaters
Large range of
contaminants
Diffuse sources
Organic contaminants
may not attenuate in
aquifer
High nutrient levels
Potentially a large
number of
contaminants
(depends on level of
pretreatment and
pretreatment process)
Organic contaminants
may not attenuate in
aquifer
Contamination with
pharmaceutically
active chemicals
(PACHs) (Bowen,
1996)
Consistent water
quality
Availability Ephemeral creeks &
streams
Stream flows are
typically of short
duration
Large variation in
quantities of water
available
Large variation in
water quality
Impacts on dependent
ecosystems
Geochemical
reactions between
aquifer matrix and
source water may
render water
unsuitable for
intended enduse
Ephemeral creeks &
streams
Stream flows are
typically of short
duration
Large variation in
quantities of water
available
Large variation in
water quality
Geochemical
reactions between
aquifer matrix and
source water may
render water
unsuitable for
intended enduse
Constant supply at
known rates
Small variation in total
flow
Geochemical
reactions between
aquifer matrix and
source water may
render water
unsuitable for
intended enduse
Filtration Filtration required to
remove suspended
sediments
Treatment may be
necessary to control
iron bacteria around
injection.
Filtration required to
remove suspended
sediments
Wetlands can provide
filtration treatment
adding to aesthetic
value of site
High levels of filtration
required
Filtration
infrastructure may be
very expensive
Demand Typically to meet
irrigation demands
Freshen up native
groundwater
Typically to meet
irrigation or industrial
demands
Freshen up native
groundwater
Can be treated to a
level for beneficial
enduse
Microbiological Open storage may be
subject to infection eg
cryptosporidium or
giardia
Treatment for faecal
coliforms
Impacts of injected
water on groundwater
ecosystems unknown
Open storage may be
subject to infection eg
cryptosporidium or
giardia
Treatment for faecal
coliforms
Impacts of injected
water on groundwater
ecosystems unknown
cryptosporidium or
giardia may enter the
system
Treatment for faecal
coliforms
Impacts of injected
water that is nutrient
rich on groundwater
ecosystems unknown
Page 28 of 62
Creeks & rivers
Urban stormwater Reclaimed water
Disinfection
byproducts
(DBP)
If chlorination is
overused this may
occur although some
evidence indicates
that DBP quickly
attenuate in aquifer.
Concern is mainly
about trihalomethanes
(THMs) & halo-acetic
acids (HAAs)
If chlorination is
overused this may
occur although some
evidence indicates
that DBP quickly
attenuate in aquifer.
Concern is mainly
about trihalomethanes
(THMs) & halo-acetic
acids (HAAs)
If chlorination is
overused this may
occur although some
evidence indicates
that DBP quickly
attenuate in aquifer.
Concern is mainly
about trihalomethanes
(THMs) & halo-acetic
acids (HAAs)
Clogging Results from
inadequate filtration
Inadequate
monitoring of source
waters
Inadequate treatment
and incorrect
operation of injection
wells
Results from
inadequate filtration
Inadequate
monitoring of source
waters
Inadequate treatment
and incorrect
operation of injection
wells
Results from
inadequate filtration
Inadequate
monitoring of source
waters
Inadequate treatment
and incorrect
operation of injection
wells
Infrastructure For small schemes
can be fairly simple
and cost effective
For small schemes
can be fairly simple
and cost effective
Must be suitable for
large schemes where
large volumes of
water require filtration
Confining bed
integrity
If gravity recharge
generally no problems
Pressure recharge
needs to be carefully
managed to prevent
failure of confining
beds
If gravity recharge
generally no problems
Pressure recharge
needs to be carefully
managed to prevent
failure of confining
beds
If gravity recharge
generally no problems
Pressure recharge
needs to be carefully
managed to prevent
failure of confining
beds
Failure rate In rural areas
individual small
schemes failure rate is
high
Geochemical
reactions between
aquifer matrix and
injected water may
result in failure
Unless adequately
monitored failure rate
will be high
Geochemical
reactions between
aquifer matrix and
injected water may
result in failure
Capital investment is
high therefore ongoing
maintenance is high if
systems are to have
an operating life
beyond 10 years
Geochemical
reactions between
aquifer matrix and
injected water may
result in failure
Operational Small schemes low
maintenance
Small schemes low
maintenance
Large schemes high
maintenance
Ongoing costs Approximately $3-
5000 per year
depending on number
of samples that must
be taken to comply
with regulations
Approximately $3-
5000 per year
depending on number
of samples that must
be taken to comply
with regulations
Could be up to
$100000 per year
depending upon the
scale and complexity
of the system
Space for
capture
Rural setting has
ample space to
establish capture
dams
Urban setting limited
space for capture
dams/wetlands
Opportunities to
provide attractive
water features within
urban environment
Associated with
treatment plant and
types of treatment
processes
Page 29 of 62
4.1. Issues associated with aquifer types in South Australia
4.1.1. Unconfined aquifers
Implementing ASR within an established urban setting presents its own set of unique
challenges. Some of the issues that need to be addressed include:
Potential damage to existing infrastructure through soil salinisation
resulting from rising water tables and also differential swelling of soils
Increased saline groundwater ingress into sewers.
Costs associated with retrofitting and redesigning existing established
infrastructure
Many of the technologies employed or newer construction materials
available today which can facilitate enhanced recharge are unfortunately
more costly than traditional materials which makes it difficult for these
newer materials to be universally accepted as a viable alternative.
In some instances the volumes of water that can be captured are far in
excess of local consumptive use which can result in waterlogging and
other undesirable outcomes.
Soil sodicity in many localities as a result of evaporative fluxes or
historically low lying coastal swamps and tidal estuaries groundwater
being very saline. Through increased recharge resulting in rising
groundwater levels the saline water reacts with the soil chemistry.
Reducing the salinity of sodic soils can reduce the soil permeability.
Inability to ensure protection of groundwater quality from pollution by
contamination from surficial infiltration.
4.1.2 Confined aquifers
Within an urban setting, deep confined aquifers offer the capacity to store large
volumes of water without the associated disadvantages of shallow aquifer systems.
Deep injection wells can be relatively unobtrusive and the filtration equipment can be
disguised in many clever ways. If treated wastewater is likely to be the source for
injection and subsequent reuse, opportunities may exist to use existing infrastructure
to distribute the water to the various demand centres.
Confined aquifer systems offer the best scope to manage the injected water as it
tends to stay within close proximity of the injection well allowing easy recovery.
Consequently, recovery efficiencies tend to be higher than for unconfined or fractured
rock aquifers.
The majority of successful ASR schemes within South Australia operate in deep,
confined, Tertiary Limestone (calcarenite) aquifers. While these aquifers typically
exhibit low to moderate hydraulic conductivity allowing for injection rates of a
maximum of around 26L/sec, they have some advantages that facilitate easy
management of ASR schemes. The sandy limestone is sufficiently well consolidated
to facilitate open-hole completion as part of the design strategy. This method of
completion provides a number of alternatives for well rehabilitation in the event that
clogging occurs. Dissolution of the aquifer matrix material (Tertiary limestone) by the
injected water helps to maintain steady rates of injection and delays the loss of
injection efficiency from clogging.
Injection wells that are screened have been less successful as the screens usually
become blocked with fine particulate matter and cease to be efficient. Clogging of the
screens can be minimised by increasing the degree of prefiltration prior to injection.
Page 30 of 62
However, in the majority of cases where clogging of the well screen has occurred,
the source water has generally been from creeks containing fine suspended solids
and the operators were unwilling to pay for additional filtration. Consequently, the
injection wells failed within a few months of operation.
Limited success has also been achieved in very fine sand aquifers in South Australia.
Wells completed in such formations require gravel packs and screens with small
apertures. For example, at Urrbrae, lignitic material in the aquifer clogged the well
screen on recovery. To eliminate this problem at the Urrbrae site, injection and
recovery was carried out at low velocities to avoid mobilisation of the lignitic material.
The well ultimately clogged due to algal matter that had passed through the pre-filter
(rapid sand filter) and become entrapped on the inside of the screen within the well.
The algal mass facilitated biofilm growth within the gravel pack surrounding the
screen. Failure of the ASR well often results from clogging but more typically it is a
result of inappropriate well construction. Construction and well completion is one of
the key factors to undertaking a successful ASR project and the method of
construction employed is dependent on the target aquifer formation type. More often
than not a specifically constructed well for the purpose of ASR will be required rather
than injecting down an existing well.
A number of small ASR schemes have failed as a result of trying to force the water
into the well at a rate faster than the aquifer can accept. This typically results in large
pressure uild-ups within the bore that ultimately fracture the formation around the
well causing the well to collapse. The majority of successful ASR sites within South
Australia use gravity injection.
4.1.3 Fractured rock aquifers
Fractured rock aquifers like confined deep sedimentary aquifers also offer good sites
for injection of captured stormwater. There are sites that have been operating in
South Australia for a number of years principally using gravity recharge. One
drawback to undertaking ASR in a fractured rock aquifer is that injection rates are
very slow. The consolidated material allows for open-hole construction of wells but
the crystalline nature of the rock limit the options for well remediation in the event of
clogging.
Because the water is contained within the fractures, the available storage capacity is
relatively small. The fracture networks can be connected over very large distances
consequently, the injected water may travel large distances from the injection well
within a very short timeframe. The ability for the water to travel large distances also
impacts on the recovery efficiency of the injected water which may be as low as 15%
(Harrington et al, 2001). This also has impacts on nearby users especially if the
injected water is of a low quality potential. Remediation is likely to be very difficult in
the event of contamination and consequently, at this stage injection into fractured
rock aquifers should be confined to captured stormwater or creek runoff.
One advantage of the fractured rock aquifer is that the crystalline rocks can withstand
greater hydraulic loadings which means that injection under pressure can be
undertaken without risk of the formation failing. In addition, if the fracture openings
are of a sufficient aperture they may allow for slightly more turbid water to be
injected. In turn this will allow economies in the level and type of pre-filtration.
Conversely, the fracture aperture may be such that clogging occurs almost
instantaneously.
Page 31 of 62
Additionally, attenuation of any pollutants (herbicides or pesticides) is likely to be
different within a fractured rock aquifer system than a sedimentary aquifer system.
A further risk associated with fractured rock aquifers is that previously inactive
springs may be reactivated as a result of the enhanced recharge, potentially causing
localised problems.
4.2. Regulatory issues
Care is needed in applying ASR as a solution where aquifers are over-exploited. It
should never be seen as an alternative to increased water use efficiency, or
relaxation of quotas or their policing. However with good resource management, ASR
can be a support for demand management (Figure 5). For example, the community
can perceive setting prices or increasing prices of groundwater as yet another tax.
However a two handed approach, where the additional revenue raised is invested in
establishing ASR for a depleted aquifer, gives a defensible reason for increasing the
price of water. A sufficient price increase will assist the community of groundwater
users to value the resource and improve water use efficiency, and thereby reduce
demand. The increase in recharge provided by ASR can mitigate the magnitude of
the required reductions in demand to achieve a sustainable water balance. ASR can
also be targeted to locations within a regional aquifer where pressures are most
affected, or where environmental consequences of pressure reductions would be
most severe, such as where saline intrusion could be induced. It would be very
difficult to equitably reduce demand on the regional aquifer to gain the same level of
protection for the aquifer.
Figure 5. Twin strategies for managing over-exploited aquifers
Clearly for successful implementation of such policies there is a need to establish
suitable consultative mechanisms to allow satisfactory stakeholder negotiations.
Without the success of existing ASR projects and the sound research base on which
they are founded it would not be possible to recommend to communities that
investments be made in recharge enhancement. This is a management tool that has
been developed by DWR and its collaborators and enables much more flexibility than
counterparts in other states currently enjoy. It is important that ASR therefore be part
of an integrated water solution, and is not treated as a band-aid measure to fix local
problems that are otherwise intractable. In this way SA will continue to lead the field
in innovative groundwater management.
Local Solutions
Local Solutions
• Reduce Demand
• Expand the Water Resource
demand supply
Page 32 of 62
4.3. Lessons from ASR failures
Six known failures have occurred in ASR pilot projects in SA, from more than 40 site
investigations. The first failure was at a well where a market gardener on the
Northern Adelaide Plains attempted to inject water from one production well into
another. The injection well and injection system was not appropriately designed for
this purpose and it is likely that air was introduced into the well and blocked the pores
of the aquifer at the well face. As no data was recorded it is not known whether there
were other causes for the unsatisfactory rate of injection. The exercise was
abandoned and caused unnecessary loss of local confidence for several years in the
potential for ASR, in spite of other successful preliminary trials in the same area.
The second failure was at a location where the most suitable formation for water
storage at a site appeared to be a thick bed of dry sand above a deep watertable.
The area was on a plain with a low slope and after a period of injection, groundwater
started to discharge at the ground surface in the gardens of private residences down-
slope of the injection site. Evidently the target 'aquifer' was dry because the water
table position reflected equilibrium between natural recharge and discharge. The
unconfined aquifer was sufficiently transmissive that a storage volume could not
accumulate without conspicuously increasing discharge to the land surface. Clearly,
knowledge of the groundwater system is essential, particularly for unconfined
aquifers, to avoid damages that could significantly exceed the value of the water
stored and recovered.
A third failure occurred when a domestic-scale ASR well was installed in a private
property in Malvern. Roof runoff was used to recharge a well completed in a
Quaternary alluvial aquifer. The large roof area and low injection rate meant that a
very large surface water detention storage was required if a significant fraction of roof
runoff was to be recharged. The detention storage overflowed onto soil and when
the water subsequently returned to the well it was dirty, contributing to clogging. The
well was freshened sufficiently for groundwater to be blended with mains water for
garden irrigation, but its use as an ASR well was abandoned.
A fourth failure occurred where a large diameter well was drilled to a thin alluvial
gravel aquifer for gravity drainage of stormwater. The well was completed as a
concrete caisson to the depth of the aquifer at about 17m and grouted on the outer
perimeter. Trials using mains pressure water revealed that the grouting was not
effective. After a short period of pressure injection into the well, the ground around
the well became waterlogged. Clearly water was migrating upwards through the
alluvial mixture of clays, sands and gravels assisted by unintended preferential
pathways adjacent the caisson. Acceptance rates were sufficiently low, such that
injection would need to be via gravity however the quantities of stormwater to be
captured required the establishment of a huge number of injection wells and large
surface storage areas for ASR to be viable at this site.
The fifth failure was in the Willunga Basin where water from an ephemeral stream
was pumped into a well. Recharge occurred without sufficient detention time to allow
suspended solids to settle or without adequate pre-filtration resulting in muddy water
entering and blocking the well. In addition the operator attempted to inject at rates
well in excess of the capacity of the aquifer to accept the water causing a pressure
head to build within the well resulting in ultimate fracturing of the formation and well
collapse. Better control on the quality and rate of injection would have circumvented
these problems.
Page 33 of 62
Finally, in the sixth case Plio-Pleistocene fine-grained unconsolidated sand between
60 and 80 m below ground was chosen as the target aquifer at the Urrbrae wetland.
The well was rotary-drilled using mud, so formation physical properties could only be
determined from mud samples and geophysical logs. The samples showed the
presence of coarse sands and also some lignitic bands. The screened intervals and
apertures (0.5 and 1mm) were set on the basis of the geophysical logs (gamma and
resistivity) and particle size distributions inferred from washed mud samples.
Development of the well took several days indicating that the proportion of fine
materials present was greater than anticipated, and had been disguised by the
drilling mud. Recognising the potential for injection to disrupt the gravel pack that had
been developed, tests were performed to inject water at different rates, and
determine the length of time after which recovered water was clear. Injection rates
were restricted to only about half the injection rate that could be achieved in order to
maintain the gravel pack effectiveness.
Unfortunately, at this site the injection system was activated approximately a month
before the recovery pump was installed in the injection well. During this period the
stormwater was rich in algae, and it was subsequently found that while the rapid
sand filtration system broke up the algal matter, it did not reduce the turbidity, organic
carbon or nutrient loadings entering the well. There was also at least one input of
engine oil from the stormwater catchment and evidence that traces of oil had got
through the sand filter and into the well. Although a monitoring well had been
included in the design of the ASR operation, it had not been constructed due to
budgetary constraints, so the reasons for the decline in flow rate could only be
guessed. By the time the pump was installed, the capacity of the well for injection
and recovery had been reduced to one sixth its initial rates.
Attempts to restore the well included; repetitive surge pumping, injection of chlorine
disinfectant and dispersant, and bailing to recover sand that was found to cover the
third of the three slotted intervals. Video monitoring of the well showed that sand was
entering the well from a small gap between the top screen and the casing, possibly
vandalised from a star dropper (metal fence post) that had been dropped in the well
(also dislodging the pump shroud), or damaged through the bailing process that had
been complicated by the buried shroud. Down-hole velocity flow metering confirmed
that the loss of third screen interval was not the cause of the substantial decline in
injection rate. It is concluded that the injection system is not adequate for this aquifer
and that the absence of a monitoring well prevents a much clearer description of the
requirements for sustainable operation of this site. As a result of this experience fine-
grained unconsolidated aquifers are regarded as unfruitful targets for operational
ASR systems in the Adelaide metropolitan area until further research on such
systems is undertaken, and appropriate procedures for flushing and topping up
gravel packs are incorporated into well design.
In summary, lessons from these experiences are that it is necessary to obtain good
samples of aquifer materials, to know the quality of the injectant, to have a nearby
monitoring well, to defer injection until a recovery system is in place, to understand
the groundwater system and potential environmental consequences of ASR, to
monitor flows, heads and quality intensively during the first phases of an ASR
operation in order to understand the performance characteristics of the well and to
determine appropriate redevelopment and well maintenance strategies, and to have
contingency plans in place to deal with issues such as turbid water, pollution,
clogging, and adverse effects on groundwater. A staged approach to ASR
development minimises investment risks, and most of these failures could have been
averted with a more systematic and comprehensive approach. Further details are
given in Dillon and Pavelic (1996), Dillon et al (2000) and EWRI/ASCE (2001).
Page 34 of 62
5. RESEARCH
5.1. Outcomes of Australian ASR research
The Australian research on ASR commenced in 1992 with a project to assess the
potential for ASR in the upper Quaternary aquifer beneath the Adelaide metropolitan
area (Pavelic et al, 1992). This was followed with a field experiment at Andrews
Farm, supported by CSIRO, Department for Mines and Energy, Hickinbotham Homes
and the Urban Water Research Association of Australia (Dillon et al, 1997). An
injection well was constructed in Tertiary limestone near a stormwater detention
pond, and following storm events over the next four winters, water was pumped into
the well from a pump mounted on a pontoon moored in the detention pond.
Groundwater was initially brackish having a salinity of more than 2,000 mg/L. The
injected water was fresh (<200 mg/L TDS) but turbid, and in the winter when most
water was injected (100 ML) its suspended sediment concentration averaged more
than 150 mg/L. It was considered quite extraordinary that the well would accept that
quality of water given that ASR operators in the Netherlands, England and USA
regard source water turbidity more than 2-5 NTU as unacceptable. Furthermore,
unlike conventional practice in USA the water was not chlorinated prior to injection.
Even in the newly released standard guidelines for Artificial Recharge of
Groundwater (EWRI/ASCE, 2001), it is recommended that injectant is disinfected to
prevent bioclogging of the well. It became obvious through further research that there
were processes occurring in the aquifer that counteracted the effects physical
clogging by suspended solids and bioclogging by micro-organisms.
Although initial efforts at ASR were successful, in retrospect they seem primitive in
comparison with best practice that has subsequently emerged from ongoing
research. At the Andrews Farm pilot project, there was a detention storage, not a
wetland. The pond sides were too steep, and ASR operations gave a range in water
levels that was too large for reeds to establish. Consequently, any new storm or
windy day resulted in wave action on the un-vegetated clay banks resuspending
clays. Furthermore, it was found that drying of the clay liner of the pond had resulted
in cracks that were infilled by coarser solids during stormwater inflows, and
consequently the pond leaked severely. Calculations showed that over the four years
of stormwater injection, as much water seeped through the pond bed to the
unconfined aquifer as was injected into the underlying confined aquifer (250ML).
Wetland designs have improved, and for the same volume of cut and fill much better
passive improvement in water quality can occur, and as much active storage can be
produced, even when restricting this to 100mm for maintenance of aquatic and
riparian vegetation. Engineered water management improvements have also grown
from a coarse screen to prevent diatoms clogging the well during blooms in the
wetland in spring and autumn, to parallel rapid sand filters, and control systems that
can shut down injection if turbidity or electrical conductivity lie outside specified
tolerances, and trigger redevelopments to prevent well clogging.
Examples of how these may be achieved for a stormwater ASR project are shown
later in Figure 7. Stormwater can be sourced selectively. Figure 8 shows this as a
capability to divert water from a stream or drain into an off-stream wetland based on
the quality (eg turbidity) of the flow. This could also occur for example by selecting
only roof catchments and not collecting runoff once it had reached the ground.
Selecting an aquifer that is brackish gives much more room for flexibility on the
quality of injectant than targeting an aquifer that is already of potable quality, where
injectant would need to be consistent with drinking water uses. Maintenance of
equipment, such as recalibration of sensors and checks on control systems are
Page 35 of 62
needed and contingency plans need to be formulated and communicated so that all
know how to deal with for example polluted water entering the injection system or
aquifer.
An important consideration that has developed from this work is that proponents of
ASR projects need to ensure that proper account is taken of the monitoring and
management costs of the project when evaluating the costs and benefits and
deciding whether to proceed. In this way there is a clear economic incentive for the
operator of viable projects to proceed. It would be very unfortunate to have operators
cut corners, as when this occurs, not only are projects likely to fail (eg via clogging),
but there is also insufficient data to determine the exact cause of failure and whether
and how it could be fixed. An international literature review, together with the
Andrews Farm data led to Australian guidelines for the quality of water for injection
and recovery into aquifers being published (Dillon and Pavelic, 1996). These are not
part of the National Water Quality Management Strategy series of documents, but
rely on the principles of the Strategy, and went through review by state government
natural resource and environment regulators in all states.
Aquifers that have been demonstrated in Australia as suitable for ASR are limestone
and fractured rock. Open-hole completions are the easiest form of well completion for
ASR well maintenance. However there is still insufficient research on wells in
unconsolidated or unstable media requiring a screen and gravel pack to provide
definitive advice on well maintenance. American experience with use of disinfected
potable-quality injectant in such wells indicates these can be very successful (Pyne,
1995).
Other outcomes of ASR research, besides the operational stormwater ASR sites and
the guidelines, are maps of ASR potential for some regions and the adoption of ASR
as part of state water plan for South Australia (SA Department for Water Resources,
2000). It has also resulted in the development of new techniques; to monitor
pathogen survival in aquifers, to measure the ability of low-grade waters to clog
aquifers, to measure hydraulic conductivity in 3D at in-situ stresses, and has
advanced knowledge of physical and biological clogging processes (2 PhDs)
geochemistry of ASR in limestone aquifers, and mixing processes and prediction of
recovery efficiency in heterogeneous aquifers.
5.2. Current research
Current research is examining subsurface processes where reclaimed water is
injected into aquifers with a view to determine criteria for sustainability of such
systems. The Bolivar reclaimed water ASR research project has injected 250ML
reclaimed water into a limestone aquifer and has numerous observation wells, and
an intensive sampling and logging schedule with various specific experiments
overlayed. The aims and outline of that project with the results of the first stage (prior
to injection) have been reported elsewhere (Section 3.2 and Dillon et al, 1999).
Another major piece of research is a project to assess water quality improvements
during ASR for the American Water Works Association Research Foundation, with a
focus on potable water supplies. Water quality parameters of most interest are
pathogens (particularly viruses), disinfection byproducts (notably trihalo-methanes),
endocrine disruptors (five indicators are being tested), and natural organic carbon
components that may be important as precursors for formation of disinfection
byproducts. The research embraces five sites in USA, four in Australia (Bolivar,
Andrews Farm, Clayton and Jandakot, WA) and one in the Netherlands, and includes
researchers from Australia, the Netherlands, France and USA. A brief summary of
Page 36 of 62
early progress is about to be published in accessible form (Toze et al, 2001) and
indicates that ASR offers some scope for improvement in all these aspects of water
quality.
In addition sites at Warruwi (NT) and Jandakot are in demonstration phase to
evaluate operational performance with a view towards including these sites within
their routine water supply systems when there is sufficient proof on their reliability to
produce adequate quantities of water of suitable quality. A number of other sites are
undergoing similar investigations, such as Willunga reclaimed water and Parafield
stormwater ASR projects in South Australia, as detailed in section 3.1.
5.3. Future directions for research and application
Cases such as stormwater ASR into limestone aquifers for non-potable reuse have
clearly moved beyond the research phase, and are now in routine use within the
consulting profession and with some client groups, such as local government.
However there are still aquifer types, notably unconsolidated or unconfined aquifers,
water types, notably mains water and reclaimed water, and reuses, notably potable
supplies, that are still in the research phase or where research has not yet
commenced for ASR. Transitions from single well systems to separate injection and
recovery wells for higher valued reuses are likely and have not yet been explored.
Use of reservoir spill to assist with opportunistic flushing of brackish or saline aquifers
has not yet started. Conjunctive storage of energy and water has not yet begun in
Australia. These new water management tools open possibilities for better
environmental and commercial outcomes in the future. With these extensions to
existing knowledge the scope for ASR to add value to water management in South
Australia and elsewhere will expand considerably. This is likely to have the effect of
trebling the potential for ASR, increasing the benefits to the state, improving the
efficiency of operation, reducing risks of failure and lowering capital and
establishment costs. For these benefits to be realised however, there also needs to
be maintenance and enhancement of current expertise within state government, in
order to manage this expanded uptake of ASR. This is best obtained by continuing
involvement in research projects with research partners such as CSIRO.
On the way there is still much to be learned about disturbed aquifer ecosystems,
virus survival and transport, fate of colloids and organic carbon introduced to
aquifers, and biogeochemical processes in the subsurface. Regulators and
proponents will need to have information more conveniently packaged in the form of
ASR water quality risk assessment models, clogging simulators, and predictors of
recovery efficiency and storage capacity in heterogeneous aquifers. These in turn will
lead to refinements in guidelines and codes of practice and reduce risks and costs for
investors. Such research would need to be well linked with the proposed new
national water reuse research program. Information from operational sites will also
need to be harvested, for environmental protection and water resources
management purposes, and be accessible to researchers so that continuous
improvements to ASR technology can proceed. Other forms of water banking in
Australia also have substantial latent opportunities, and the ASR research base
provides a very convenient and efficient launching pad.
Page 37 of 62
6. SUMMARY OF COSTS AND BENEFITS TO SA
South Australia uses 1240GL/yr of its average available resource of 2610GL/yr
(Table 9). However this apparently large buffer of surplus capacity is largely illusory.
The largest component, approximately 1000 GL/yr of groundwater, cannot be
exploited without serious impacts on wetlands and riparian vegetation (including
some pasture and forests) in the South East of South Australia. Further exploitation
of the River Murray would be contrary to the aim of all the states through which it
passes to maintain or increase environmental flows in this depleted stream. Other
surface water resources also have environmental flow considerations, or the cost of
dams in relation to yield would be extravagant. Hence it is apparent that South
Australia needs to conserve, recycle and reuse water, and to harvest urban rainfall
and stormwater which until the last decade was a minimally tapped resource.
Management of urban flooding using wetlands and detention storages has triggered
stormwater harvesting and a diversity of innovative approaches have been
developed. The one having the largest impact is ASR.
Table 9. Water Resource and Water Use in South Australia and in
Adelaide and the Mount Lofty Ranges (from DWR, 2000)
Water Resource State Use
Limit
(GL/yr)
State Use
(GL/yr)
Metro Adel
Use Limit
(GL/yr)
Metro Adel
Use
(GL/yr)
River Murray 700 600 130 110
Other surface water 220 140 84 130
Groundwater 1440 460 74 61
Stormwater runoff 130 20 110 21
Treated effluent 120 20 79 17
Total 2610 1240 477 339
To date ASR has focussed on stormwater runoff in the Adelaide metropolitan area,
and current research is exploring the potential for expansion of use of reclaimed
water (treated effluent). These are the two smallest sources of water in South
Australia but are significant sources for the metropolitan area. More will be said on
this later.
Research proposed in section 5, would expand ASR to storing potable quality water
derived from surface waters including from the river Murray near the termini of
pipelines, so that peak demands can be satisfied without pipeline duplication.
Deferring, possibly indefinitely, the capital costs of new pipelines would produce
significant savings. ASR projects could be established incrementally as demand
increases, and before pipelines reach full capacity, so that this is a viable proven
option available for expansion of regional mains water supplies. It is expected that
areas such as the northern Spencer Gulf, and Yorke Peninsula would be regions
where such benefits would be significant. The costs of ASR could be compared in
the first instance with the costs of covered terminal storages of the order of 1000ML
capacity, where capital costs would be one to two orders of magnitude more
expensive than subsurface storage. Costs would be recovered at the potable water
price. According to regional development boards in these areas, limitations on water
resources are considered a limit to growth in these areas. Again, as in the case of
over exploited aquifers, prudent water management suggests that ASR would be
instituted hand in hand with programs to encourage water use efficiency.
Page 38 of 62
In arid and semi-arid environments, the cost of alternative sources of supply is high
so ASR can compete more easily with traditional sources of water. For example, in
some country towns of SA, annualised unit costs of SA water supplies may be
considerably higher than in Adelaide due to long pipelines and relatively low water
consumption. In the northern region, for example, these range from $3.50 to
$4.70/KL and on Eyre Peninsula $5.50 to $7.20/KL (Van der Wel and McIntosh,
1996). Expansion of water supply capacity in these locations could be by
development of ASR, to make use of surplus pipeline capacity in winter.
Table 9 hides the additional surface water resources that are intermittently available
in years when reservoirs spill. Prior to and during spill events mains water from
these reservoirs could be banked in aquifers to build drought and emergency
supplies. Adelaide's traditional reliance on the River Murray has resulted in it having
the smallest surface storage to annual demand ratio of any major Australian city. For
Adelaide this ratio is 1.0. In Perth (which depends on significant aquifers), the ratio is
2.6, whereas in Sydney (4.0), Melbourne (4.1), Brisbane (7.3) and Canberra (3.4),
the ratio is higher even though their water supply catchments have comparatively
higher rainfall and less variability than Adelaide's Mount Lofty Ranges catchments
(Dillon, 1996). If we had prolonged blue-green algal problems in the River Murray or
concurrent problems in the Mount Lofty Ranges storages, Adelaide would be very
vulnerable. ASR provides a very low-cost strategy to provide short-term emergency
supplies. For this to be an option some consideration should be given to allocating
aquifers to potable water ASR. Stormwater ASR need not preclude this option, and
could help to reduce the salinity of ambient groundwater to provide a buffer zone in
which potable water is stored. This would help to keep recovery efficiencies high,
which may be important if there is internal charging for water to be banked. Clearly
there would need to be protections given to water utilities that bank water in aquifers
to ensure that they can access the water at times when withdrawals are required.
Concerning the now 'traditional' stormwater source for ASR in Adelaide, currently the
cost to users varies between 20 and 50c/KL depending on local conditions, such as
scale of operation, availability of water, and suitability of the aquifer. At first sight it
would be much cheaper to buy River Murray water licences (say 10c/KL) and pay for
pumping costs (say 2c/KL) but this does not take into account the lost return from
agricultural production (eg typically 20 to 40c/KL) depending on the irrigated crop and
water use efficiency. With loss of production there are flow on effects to incomes and
jobs in rural communities. There are also different environmental consequences, and
use of ASR retains environmental flows in the River Murray and reduces discharge
into the Gulf of St Vincent of stormwater contaminants (retained and in part
attenuated in wetlands). Therefore, although for individual users the economics of
transferring water rather than developing new water resources may seem superior,
from a State perspective, the reverse is true. The state should therefore give
consideration to setting policies that internalise current externalities and encourage
the development of water resources where these will be of most benefit to the State.
Typical costs for domestic and municipal scales of ASR schemes are summarised in
Table 10. These assume that maintenance, monitoring, and depreciation costs are
fixed annual costs, and that the only variable costs are for energy for pressure
injection (at 5c/KL/pump) and for recovery, at the municipal scale. In reality the
quantity of runoff may restrict the amount of recharge. Costs will vary from site to
site, depending on the depth of the target aquifer, drilling conditions, the extent of
pre-treatment and surface storage costs, and investigations required as part of the
environment management plan (Dillon and Pavelic,1996). These do not take into
account the costs of surface detention storage, which normally would be covered as
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a flood mitigation capital works cost, nor do they account for changes in future costs
such as energy and water.
Table 10. Comparison of estimated costs for domestic and municipal scale
ASR schemes
Costs Domestic
(500 KL)
Municipal
(100 ML)
Initial costs $2 400 $200 000
Annual cost - fixed
- variable
$200
$25
$10 000
$10 000
Total annualised cost (15yrs, 7% discount rate)
Cost per kilolitre ($/KL)
'Break even' time c/f. mainswater @ 90 c/KL (years)
$489
0.98
-
$42,000
0.42
3.3
(after Dillon, 1996)
These typical figures indicate that the break-even time for municipal scale facilities
using a single-well capable of supplying 1 to 2 ML/day continuously over summer is
less than 4 years. The expected lifetime of an appropriately constructed and
managed ASR facility is greater than 15 years. If larger annual water volumes can
be banked for the same capital costs the unit price of water can be reduced. If
warranted by surface supplies or peak demand, a series of wells can be constructed,
and some economies of scale may be possible. Domestic scale facilities at the scale
shown in Table 10, are not economic compared with mains water supplies. Possibly
this is fortunate from the point of view of aquifer protection, sustainability and equity
of access to the resource (as discussed later). Domestic rainwater tanks are more
expensive per KL of water supplied than ASR, however the capital cost is
significantly lower, and this may be a preferred option for improved domestic
rainwater management.
From a water utility perspective ASR can be viewed as a means of expanding supply
capacity during peak demand. Unit costs for ASR facilities in the United States
generally range from about AUS$100,000 to AUS$300,000 per megalitre per day
(ML/d) of peak demand capacity (Pyne et al 1996). These apply to supplies of
hundreds to thousands of ML/yr. Many of the schemes implemented thus far in South
Australia deal with smaller volumes of around 80 to 150 ML/year and the principal
enduse is irrigation. Consequently, costs are lower because the systems generally do
not require expensive infrastructure such as advanced filtration and disinfection.
Installation costs typically range from around AUS$50,000 to AUS$200,000 for 1
ML/d supply capacity during the peak demand season. On-going operational costs
are typically 5c to 10c/KL for simple ASR schemes where wetlands are used as the
filtration method and recharge is by gravity. Setup costs obviously increase when
advanced filtration pre-treatments are required to ensure that source water meets the
criteria for aquifer storage and recovery.
Incorporating ASR as one of the tools for resource management can reduce user
reliance on imported water by -
• improving groundwater quality locally for irrigation and industrial use,
• creating low salinity lenses for domestic water supply within saline
aquifers,
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• reducing outflow of stormwater to the marine environment,
• reducing the dependence of urban and rural users on the River Murray
and;
• maintaining groundwater systems for current/future development.
ASR offers a potentially low cost method of storing water as an alternative to surface
storage where aquifers are favourable. Some of the factors that must be considered
to achieve successful ASR are:
• a contracted demand for the water product, adequate to ensure the
ongoing profitability of the scheme
• surface water availability of sufficient quantity and quality,
• a suitable aquifer for long term storage, additional quality modification and
transmission (as may be required),
• suitable land for surface works involved in surface water capture,
temporary storage, treatment, transfer to the ASR site, ASR headworks
and reticulation to the demand location,
• pre-treatment of water as necessary to reduce suspended solids
concentrations, whether by wellhead filtration or by movement through
surficial sandy soils, and,
• a capital funding source for establishing the system
7. ASR GUIDELINES AND REGULATIONS
7.1. Water quality guidelines for ASR, 1996
The first issue to be addressed in ASR is the protection of groundwater quality. Until
1996, a major barrier to the storage of surface waters in aquifers via injection wells
was a lack of scientifically based guidelines on the quality of water to be injected.
The first Australian guidelines on the quality of stormwater and reclaimed waters for
injection into aquifers for recovery and reuse (Dillon and Pavelic, 1996) addressed
that gap. This superseded previous documents on artificial recharge of reclaimed
waters (AWRC 1982, and NRC 1994) and was a first attempt (internationally) to
provide a sound basis for the injection of non-potable waters into aquifers for a range
of beneficial uses.
These guidelines were an outcome of a two-year Urban Water Research Association
of Australia study that reviewed international practice and guidelines for artificial
recharge of waters by injection. The study also reviewed literature and data on the
quality of stormwater and treated sewage effluent; effectiveness of pre-treatment
methods including constructed wetlands; basins and engineered treatments; clogging
and redevelopment of injection wells; and attenuation of chemical and microbial
contaminants in aquifers. The Andrews Farm experimental ASR site was used as a
case study to demonstrate the viability and sustainability of injecting urban
stormwater that received only passive treatment in flood detention ponds, into a
brackish aquifer. The recovery was as an irrigation resource.
The principles, objectives, and guideline values for maximum contaminant levels in
water for a range of beneficial uses (environmental values) were founded on
Australia’s National Water Quality Management Strategy (NWQMS). The guidelines
were distributed for comment to water resource managers and environment
protection agencies in all states and territories of Australia, the Australian Health
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Commission, the NWQMS chairman, and water companies. Eighteen sets of
comments were received and considered in finalising the guidelines.
While the guidelines adhere to internationally accepted principles they are quite
different from those currently used to regulate ASR sites in other parts of the world
for two reasons. They do not presume potability as an essential and sole objective,
and they allow for demonstrated sustainable attenuation of contaminants by natural
processes in aquifers. Currently there are pressures within the USA to adopt the
principles embodied in these Australian guidelines, particularly in arid areas where
alternative sources of supply are possible. The American Water Works Association
Research Foundation currently supports a project (#2618) 'Water quality
improvements during ASR' aimed at gaining a better definition of attenuation of
contaminants of interest to water supply companies involved with US drinking water
quality standards. This project is led by CSIRO Land and Water and involves the
Department for Water Resources, SA Water and United Water.
The guidelines covered licensing, pre-treatment, monitoring, guidance for maximum
contaminant concentrations in injectant, residence time prior to recovery and
management of ASR operations.
The report also made recommendations on revising the guidelines as identified
knowledge gaps are addressed; concentrating research at selected sites; and
establishing a national ASR research program to coordinate and conduct ASR
research; collating all monitoring data and reports from Australian ASR sites; and
producing a design manual for ASR. Knowledge gaps were also identified to help
focus research and enable the guidelines to be improved.
7.1.1. Specific guidelines
The guidelines contained specific recommendations concerning licensing, pre-
treatment, monitoring, maximum concentrations of contaminants in injectant, and
minimum residence time. A condensed summary follows.
Licensing
There should be two types of licences. Proposed new ASR sites should be subject to
a demonstration licence for a specified trial period, typically three years, to enable
demonstration of achievement of the three objectives; protection of groundwater
quality, ensuring that the quality of recovered water is fit for its intended beneficial
use, and that clogging is managed effectively. The demonstration licence would be
based on an environmental management plan to account for all environmental
impacts and associated risks. The plan would include appropriate monitoring and
reporting to demonstrate performance with respect to objectives, operational and
contingency plans to manage risks, and projections of performance over the longer
term. Appropriate opportunity for public comment should be allowed. Issue of a
longer-term operating license, and its conditions, would be subject to a performance
review of the demonstration period.
Pretreatment
The overarching principle should be to remove or reduce whatever contaminants can
be viably attenuated at the surface before injection, in particular those contaminants
that are resistant to degradation in the aquifer.
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The minimum level of pretreatment required for a demonstration licence is that which
results in predicted achievement of water quality criteria (eg. NWQMS 1992a, 1994b)
relevant to all pre-existing potential beneficial uses for the aquifer. Where the
beneficial uses of recovered water are different from those of the ambient
groundwater, pre-treatment combined with aquifer treatment should meet the
relevant criteria at the point of extraction. This will determine whether disinfection or
any other pretreatment is required during the period of the demonstration licence.
Pretreatment methods may include passive and engineered systems, or a
combination of these. There will be at the discretion of the proponents as part of their
environmental management plan.
Where any relevant water quality criterion is not initially met by the ambient
groundwater, excluding the effects of anthropogenic pollution, the injected water only
needs to have a concentration less than that of the ambient groundwater - at least
for the period of the demonstration licence.
Detention storage as part of pretreatment is desirable in reducing the variability of
the quality of injectant. This has the advantage of increasing confidence in the
results of monitoring for any given level of monitoring effort.
Monitoring
At least one observation well is required at each ASR site, and where reliance is
placed on water treatment within the aquifer to meet water quality objectives at least
three (3) observation wells in addition to the injection well are recommended. In
fractured or heterogeneous aquifers more wells may be needed. Extraction wells
may be used as observation wells, if sited appropriately. In areas where existing
drainage wells or ASR operations are prolific, and have a history of use, a
rationalised monitoring program designed on risk management principles may be
adopted in the environmental management plan.
For new operations at least one observation well should be located down-gradient
on the flow path through the injection well. This is to monitor breakthrough of
injectant within the period of the demonstration licence. The other wells are required
to establish the direction of ambient flow at the site.
The parameters to be measured are those appearing in the water quality criteria for
the potential beneficial uses (NWQMS 1992b; 1994b), prior to, and following
establishment of the ASR site. Exclusions may be granted by the regulating authority
on the basis that certain contaminants are known not to be present in the source
water.
There is a need to be able to track the injectant in the aquifer, and determine the
proportion of injectant in recovered water. If there are no obvious contrasts between
injectant and groundwater, use of ‘natural’ isotopes or CFC’s as tracers is
recommended. Measurement of the mass of contaminants and solutes injected into
aquifers (and recovered) will be a valuable aid for total catchment management.
The monitoring frequencies for a wide suite and a surrogate (smaller) suite of water
quality parameters should be determined on a site-by-site basis, and from a risk
management perspective, by the regulatory authority. This would take into account
the source of the water for injection and its quality, proposed pretreatment methods,
aquifer characteristics, groundwater quality, existing and proposed uses of
groundwater and sampling locations.
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If, during the demonstration licence period, monitoring shows that the water quality
objectives are not met (ie. predicted rates of treatment above and below ground are
not achieved), pretreatment should be upgraded accordingly, and if necessary,
contingency plans put into action to ensure that adverse effects do not persist.
Sites proven by monitoring to achieve their water quality objectives during the
demonstration licence period, should be granted a full licence for a period to be
nominated by the regulatory authority, with appropriate terms and conditions.
Guidance for maximum concentrations of contaminants in injectant
Guideline values for individual parameters should be determined by water quality
objectives and by the capacity for treatment within the aquifer. The following
information is provided as a general guide on several parameters that are commonly
regarded as constraints to ASR with reclaimed waters.
Suspended sediments - Where bore redevelopment is required more frequently than
daily, the suspended sediment concentration of injectant should be reduced. Values
of 30 mg/L have been acceptable in a variably cemented limestone aquifer. Finer
grained aquifers with no macroporosity will require considerably lower suspended
solids.
Total dissolved solids - A maximum of 500 mg/L is recommended for potable reuse
and 1000 mg/L is desirable for non-potable reuse, although higher values may be
used where these are locally acceptable for environmentally sustainable irrigation
systems or other beneficial uses, provided these do not exceed the TDS of ambient
groundwater. These figures assume that TDS is approximately conservative. Where
wastewater is more saline it may need to be blended with surface water to reach
these values prior to injection.
Faecal coliforms - A maximum of 10,000 colony-forming units per 100 mL is
recommended. Allowing for 1 log cycle removal per 10 days (which is conservative),
faecal coliforms would be depleted to the irrigation water quality guideline after 10
days and to near potable standards after 50 days residence in the aquifer.
Nitrogen - For potable reuse a maximum of 10 mg/L is recommended, subject
to ammonia concentrations being less than 0.5 mg/L. Denitrification within the
aquifer should not be relied upon to attenuate nitrate concentrations as this may
cause gas binding. For irrigation reuse the nitrogen concentration in recovered
water should be sufficiently low (typically less than 10 mg/L) that the nitrate
concentration in irrigation leachate is environmentally sustainable. Where
groundwater containing injectant discharges into surface waters or estuaries, the
receiving water concentrations should remain below 0.1 mg/L.
Minimum residence time
A minimum residence time of 50 days for undisinfected injectant is recommended to
provide an acceptable degree of health protection when recovered water is used for
recreation or irrigation. Shorter residence times may be allowed if source water
quality and exposure paths provide an equivalent level of public health protection.
Protozoa and viruses may have longer survival times in aquifers, and recovered
water should not be used for water supplies unless there is either a field-based
assessment of the potential for breakthrough of these species, or the injected or
recovered water is suitably treated.
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7.1.2. Operation of ASR sites
The 1996 guidelines also recommended a series of measures to assist in
achievement of the licensing objectives. These recognised that injection of water
bypasses the natural protection afforded confined aquifers by their confining beds.
The high costs of remediating contaminated groundwater, injectors of reclaimed
water have an obligation to establish that their operations meet the three licensing
objectives. The need to provide this assurance, together with the current
uncertainties in our knowledge of contaminant attenuation, requires that an
environmental management plan include the following features:
• sites that are initially treated as pilot or research operations until the
regulatory authority is assured that the objectives have been met in a way
which can be sustained,
• impacts on groundwater quality and the fate of contaminants in aquifers are
monitored,
• effects of the operation on piezometric pressures, aquifer leakage rates,
groundwater-dependent ecosystems, groundwater discharge rates and
groundwater quality are monitored and changes predicted,
• number, location, and design of observation wells, the frequency of sampling
of these and of injectant and recovered water, and the analyses required
should be determined for local conditions and be based on an assessment of
the risk of contamination,
• safeguards are in place to prevent injection of unacceptable water,
• contingency plans are produced to provide for the recovery of any polluted
groundwater, and if the site is to be continued, contingency plans are
prepared for the establishment of appropriate pretreatment to enable
objectives to be met,
• plans for well redevelopment (or other methods for unclogging injection
wells), means of disposal of recovered water and sediments have been
considered and are acceptable,
• consequences of changes in source water quality and supply, and changes in
the demand for recovered water are considered, the effects understood, and
the management response plan acceptable,
• results of monitoring are reported (and related to predictions) at agreed
periods
• proponents of new or expanded ASR facilities lodge, with the relevant state
government authority, a report containing - geological logs; groundwater
quality and source water analyses; design of system; estimated annual
volume of source water available, and target volumes for recharge and
recovery; injectant water quality targets based on sustainability objectives and
accounting for contaminant attenuation in the aquifer(s); plans for
pretreatment of injectant; operational, monitoring, and contingency plans; and
projections of the effects of the operation. Relevant scientists, including an
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experienced hydrogeologist, to determine its technical merit should review the
report.
A well considered environmental management plan presents the opportunity to
trade-off sustainable treatment in the aquifer against pretreatment of injectant,
providing all objectives can be met. Aquifer treatment effects on recovered water
may be increased for some contaminants by lengthening the flow path and
residence time in the aquifer. This can be achieved by the suitable placement of
injection and recovery wells. The increase in knowledge of the sustainable
attenuation capacity of aquifers as a result of information collected at these sites will
allow improved design of matching pre-treatment systems, and allow costs to be
contained. This will apply particularly to non-potable uses of recovered waters from
aquifers that are initially non-potable.
The guidelines also noted a very strong linkage between environmental sustainability
and economic feasibility for proposed ASR sites. For example (Figure 6) a flow chart
to assist potential ASR operators determine economic viability, shows the impacts on
treatment costs of an inability to meet environmental objectives. Operations that are
marginally economic may be unable to meet the required costs of monitoring, and
the level of operational management may be compromised. It is important therefore
that the ASR facility is economically viable, taking account of monitoring costs.
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Figure 6. Flow chart showing the feasibility of artificial recharge with stormwater
and reclaimed water (from Dillon and Pavelic, 1996)
7.2. Draft SA guidelines for stormwater ASR
With the impending commencement of the SA Environmental Protection Policy
(Water Quality) it became clear that the 1996 ASR guidelines did not cover the range
of issues in the broader catchment management context that need to be considered
in issuing licences for ASR operations. For example, competing uses of stormwater
and environmental flows within a catchment were not addressed. Furthermore,
impacts of upstream developments on surface water quality and quantity could also
have an impact on the viability of an approved ASR project, and the potential
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constraints an ASR operation may impose on such developments needed to be
addressed.
It was also suggested that there was a need to move towards a code of practice for
ASR operators, which, if adhered to, would indemnify operators from prosecution
under the Environment Protection Act. Concurrently, there was a view that the state
should set objectives and leave it to operators to determine how to achieve these. A
consensus was reached among members of the SA Artificial Recharge Coordinating
Committee, that the state should also provide advisory information, which if followed
ought to lead to a satisfactory outcome. Operators would, however, be at liberty to
use other methods, which would be just as acceptable if they achieved the required
outcome.
Drafting of this guideline/code of practice commenced in October 1998 and at
October 1999 agreement was reached on the technical content of the document.
This covered the guiding principles to achieve best practice, a discussion of the
factors that affect the success of ASR projects, and some examples of successful
ASR operations. The latest draft of the guidelines (draft 6) was produced in April
2000 (Dillon et al, 2000).
However, the guidelines/codes of practice were also to contain advice on the
approvals and permits required as part of the ASR establishment process. This
component of the report became entangled and was still unresolved in August 2001.
The reasons for this are set out below.
However at a meeting called by the EPA on 25 June 2001, it was agreed to split the
new guidelines into two separate documents. The technical component is to be
produced as a stand-alone guideline that will not reference administrative
procedures. This can then be used as a national (or international) reference and be
subject to national peer review prior to release. The second document will outline the
licenses required and the procedures and sequence through which they may be
currently acquired in South Australia. This document will reference the technical
document, but not repeat its content.
The complexity of the licensing of an ASR project stems from the fact that ASR,
while included within the State Water Plan (Department for Water Resources, 2000)
as having a significant contribution to the development and more efficient use of
state water resources, is subject to three pieces of legislation:
• The Environment Protection Act 1993, which is concerned with the quality of
water stored and recovered ,
• The Water Resources Act 1997 , which controls the construction of wells
throughout South Australia and the recovery component in prescribed areas ,
• The Development Act , which may require approval before the Environmental
Protection Authority (EPA) can issue a licence and may require local
government approval for some components of an ASR scheme eg, storage
dams with a wall height in excess of 3m.
The licensing conditions are related to the components of the ASR scheme, the size
of the scheme, and it’s location. The approval process and licence conditions are
detailed in Appendix A of Dillon et al (2000), and are in essence:
• a well construction permit is required for all wells (Water Resources Act);
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• any water-affecting activity within a catchment water management board
boundary will require permitting from that board (Water Resources Act);
• EPA licensing is required for discharge to aquifers from areas greater than
1Ha in the city of Mt Gambier and in the Adelaide metropolitan area
(Environment Protection Act 1993, Section 4 (2) of schedule 1 and Section
36);
The EPA may issue an interim ASR licence, which allows the proponent an
opportunity to demonstrate effective ASR operational skills. On satisfactory
completion of all conditions by the proponent, the EPA may grant a full licence, to
which will be attached operational and reporting requirements. An example
demonstration licence is given in Appendix 2 of Dillon and Pavelic (1996).
Development approval is however required before the EPA can issue this Licence
(Development Act).
• In prescribed well areas, a licence to take water is required (Water
Resources Act)
Currently it is difficult to provide a “one stop shop,” given the need in some
instances, to seek approvals under three different pieces of legislation. DWR has
an ASR licence application form on its web page, and has produced several
brochures to explain ASR and assist potential proponents to consider the factors that
could affect viability before submitting applications.
The 2000 draft guidelines refer to ASR operations using stormwater at a scale larger
than household level. This leaves two major gaps:- 1) Domestic stormwater ASR
which brings a range of issues discussed at length in section 6.3 of this report, and
2) ASR with reclaimed water. This is currently in the research phase and it is
considered premature to attempt to make enduring statements on requirements for
such ASR operations.
As an example of the advances in the concepts and practice of groundwater quality
protection at ASR sites, Figures 6 and 7 show how multiple barriers can be
incorporated in the design and operation to improve confidence in effective
operation.
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Figure 7. Multiple barriers to protect groundwater and recovered water at ASR
projects (after Dillon et al, 2000)
Page 50 of 62
wetland or
detention
storage
to water
supply
scour valve
to wetland or
sludge pond
filter
disinfection
disinfection
flow
meter
flow
meter
shut off valve
water quality monitor
& sampling valve
surface water flow diversion intake
floating screen
& pontoon pump
Components of well configured ASR system
showing barriers to pollution. Systems for
irrigation supplies or taking treated water
from pipelines will generally have
fewer components.
shut off
valve
well
.
..
.
.
.
..
.
.
..
.
.
.
.
injection
line
pump for
recovery of
stored water
foot valve
CONTROL
SYSTEM
weir intake valve
water quality monitor
water quality
monitor &
sampling valve
Figure 8. Components of a well-configured ASR system showing barriers to
pollution (after Dillon et al 2000)
Page 51 of 62
7.3. Proposed SA guidelines for domestic scale stormwater ASR in
unconfined or semi-confined aquifers
Draft guidelines for domestic-scale stormwater ASR are currently under
consideration by the SA Artificial Recharge Coordinating Committee.
The benefits of stormwater ASR at domestic scale include; more efficient water
management (it is easier to deal with stormwater at its source than downstream);
potentially high quality injectant if only roof runoff and rainwater tank overflow is
used; use of an otherwise wasted resource; reduced demand on mains water
supplies; slightly reduced urban runoff into the sea or receiving waters; and, in some
cases, potential for reduced domestic water costs. In general, recharge and recovery
of small volumes of water are economic only if capital costs are very low. At domestic
scale, this will restrict the depth and types of wells and the types of treatments that
can be provided. It will also restrict monitoring costs. Expert management cannot be
assumed and provision needs to be made for ownership succession.
As the economic attractiveness of ASR is scale-dependent, it is likely that large users
of water will be first to want to do ASR and in many cases the amount of their roof
runoff will be less than the volume of water they wish to recover (Dillon, 1996). While
ASR would reduce net withdrawals from the aquifer, this form of operation is not
encouraged, as groundwater would then become a resource available only to those
who could afford to subsidise high water usage.
In sandy locations such as on the LeFevre Peninsula dune (west of Adelaide), tube
wells can be jetted in inexpensively and here there should also be an attempt to
balance groundwater discharge with recharge to avert the threat of saline intrusion if
aquifer water levels decline (Martin, 1996). On the highly permeable sands of the
Swan Coastal Plain, roof stormwater down-pipes are directed into sumps that allow
water to percolate to the aquifer, and garden water is recovered through separate
wells.
Higher groundwater levels could cause havoc. They could increase the entry of
saline groundwater to sewers: cause salt damp, movement and cracking in houses;
damage to roads and pavements; salinisation and damage to water-sensitive
vegetation; and submergence of underground utility services. Conversely, if the
groundwater levels were dropped by a recharge/discharge imbalance, the results
could include a reduction or cessation of base flows in urban streams; reduce yields
of wells; also cause settlement of building footings; and may, in coastal areas induce
salt water intrusion. ASR also increases opportunities for the shallow aquifer to
become polluted and increases the possibility of human contact with polluted
groundwater.
Given that there are limitations on the investment in failsafe control systems to
prevent these potentially significant problems, it is necessary to have a guide for ASR
in shallow systems that are practical and robust. Good design can reduce the
amount of management required by ASR well owners, but this cannot be limited
entirely, and all proponents of ASR wells will need to be aware of their ongoing
responsibilities if ASR is to produce benefits with no adverse side effects. Hence
there will be a need for education programs for ASR well owners.
Principles and practices that will lead to sustainable operations and that are
embodied in the draft guidelines
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It is recommended that ASR in shallow aquifers not be undertaken in locations where
water tables are already shallow (less than 5m), in areas where saline groundwater
ingress to sewers occurs, where water tables could rise to within 5m of the soil
surface as a result of ASR, where expansive clay soils occur, or where other
structures such as cellars or basements could be adversely impacted by rising water
tables. For the Adelaide metropolitan area, maps of depth to water table, salinity,
yield and hydraulic gradient are shown in Pavelic et al (1992), and sewer invert levels
in relation to groundwater levels are shown in Bramley et al (2000). All Australian
cities are included in state groundwater databases where similar information is
available.
The water recharged should only be at the highest possible quality and equivalent to
roof runoff after first flush bypass. This would be provided by overflow from a
rainwater tank, and it should be filtered to prevent entry of leaves, pine needles, and
other gross contaminants into the well.
No runoff from paving should be admitted, unless this has first passed through a
sand filter. (This will also help to avert clogging of the well.) If cars, motorbikes or
other machines containing petrol, oil, or other hydrocarbons parked on a paved area
which is part of the well’s catchment, an oil-grease trap is required in addition to a
sand filter.
An inventory should be made of other potential pollutants in the catchment for the
well and strategies devised to ensure these are excluded from the well, or are treated
and removed before water enters the well. Existing groundwater quality in the
shallowest aquifer is summarised for three western suburbs in the Adelaide
metropolitan area in Dillon et al (1995).
The aquifer pressure should at all times be below ground level. To achieve this,
injection should be by gravity drainage into the well, rather than using a pressurised
injection system, and there should be an overflow facility. This, for example, could be
to a garden area, where excess water does not cause nuisance to neighbours, or an
urban stormwater drainage system.
At least the uppermost 2 metres on the outside of the well casing should be cement
grouted to prevent upward leakage outside the casing and waterlogging in the vicinity
of the well.
The ASR scheme should include provision for measuring water entering the well and
water discharged from the well, with a view to keeping these approximately in
balance. Ideally, two water meters would be used, and annual records of recharge
and discharge maintained.
In areas where groundwater levels are deep or falling, there may be a requirement to
ensure that groundwater recharge exceeds extraction over a given period of several
years.
Where groundwater is naturally saline, care will be needed that the salinity of
recovered water is acceptable for irrigating salt-tolerant species, especially towards
the end of summer. During the first few years of operation, withdrawal should be less
than recharge to improve the salinity of subsequently recovered water.
The well should have provision for groundwater level measurements, such as a tube
within the well through which a water level monitoring probe can pass. The owner
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should have access to a water level monitoring probe, and an electrical conductivity
meter. He or she should be provided with hands-on training in how to use these.
Water level and salinity should be recorded at least each six months, at the end of
winter (Sept/Oct) and the end of summer (March/April). Without meters, there should
be at least an additional two water level measurements recorded annually in Dec/Jan
and June/July.
If water tables rise or fall by more than two metres at the same time of year over a
course of five years (when neither recharge or discharge is occurring), meters should
be installed and bore owners should aim to increase either net discharge or net
recharge respectively so as to re-establish a local groundwater balance.
The well needs to have a permanently equipped pump that can be activated
intermittently in winter to purge suspended solids that accumulate in the well during
injection. This water should be discharged to lawns or gardens and not be allowed to
enter street stormwater drains or sewers.
Where a property containing an ASR well is sold, the new owner is to be alerted to
the management requirements. If they are unwilling to adopt these, the well should
be backfilled with bentonite pellets, or concrete, by an appropriately qualified
contractor, the state government's well-licensing group notified, and stormwater
diverted.
Where several neighbours combine to establish a single ASR well, a legal agreement
needs to be in place setting out the obligations on each of the parties. It should cover
costs of maintenance, supply of stormwater, maintenance of the well catchment,
ownership of recovered water, the keeping of records, and the consequences of
changes to property ownership.
It is recommended that catchment water management boards provide the first point
of contact for landowners seeking to establish stormwater ASR wells or inheriting an
ASR well through purchase of a property. The boards should provide brochures on
design and operation of ASR projects; give advice on management of ASR systems;
hold template agreements for joint ASR projects; lending and give training in water
level and salinity monitoring equipment to landholders; provide access to DWR
records on well depths, yields, groundwater levels and salinities in their catchment;
and lists of contractors accredited to install and decommission ASR systems.
Successful implementation of any proposed scheme must involve consideration of:
• Site feasibility and conceptual design, including
water supply,
recharge water quality,
water demand,
hydrogeology,
recharge processes,
site characterisation.
• Regulatory and water rights issues
• Impacts on existing users
• Institutional constraints
• Economic considerations
• Legal and regulatory issues
• Environmental impacts
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Implementation of ASR must be undertaken in a coordinated and integrated manner
involving:
• Regulators
• Planners
• Practitioners
• Politicians and
• The community
8. POTENTIAL ISSUES AND OPPORTUNITIES
8.1. Domestic scale rainwater/stormwater ASR
A major issue arising from what has been outlined previously, is that the proposed
management requirements are strict, and enforcement is possibly unrealistic. The
costs of enforcement would possibly exceed the benefits to SA of the total volume of
water savings, unless this can be streamlined or outsourced. It’s a case of weighing
up the risks and benefits.
A minority of enlightened citizens, in locations where domestic stormwater ASR is
viable and with good intentions that would be backed up by good practice, could find
the above guidelines too restrictive or onerous to contemplate establishing a project.
In essence such guidelines could inhibit what, in some cases, would be best practice
in water management. However the damage that could be caused by inappropriate
operations may be many times the water benefits achieved.
It is recommended that demonstration and research domestic ASR sites need to be
established and monitored to indicate impacts on groundwater levels and quality, and
effects on the environment and structures. These sites would also demonstrate
achievable volumes of recharge and facilitate testing of robust control technologies.
8.2. Reclaimed water ASR
While it is premature to provide guidelines on ASR with reclaimed water, early
indications suggest that the management regime required for sustainable operation
will require operators to have expertise in water quality management. This, in turn,
suggests that water utilities rather than individuals like irrigators would be the most
likely holders of ASR licences.
Further information from the Bolivar and Willunga projects will be available in 2002 to
enable clearer guidance for operations in limestone aquifers.
8.3. Licensing of new ASR projects
There is an urgent need to coordinate licensing of new ASR projects. Currently this is
a time-consuming, tortuous, and not necessarily thorough process. It is
recommended that a one-stop shop be established and the communication channels
between departments, catchment water management boards and local government
be streamlined so that applications can make use of appropriate technical expertise
and local knowledge and be processed expeditiously. It would be helpful to have a
single agency with the responsibility to lead and coordinate, and as a conspicuous
point of contact for the community. DWR is the only department with the appropriate
experience to do this, but needs to be given the mandate by all other organisations.
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8.4. Monitoring and reporting of existing projects
Feedback on existing projects is currently uncoordinated and generally deficient.
There is no follow up process to chase monitoring reports nor to evaluate these and
modify the terms of licences. It is recommended that this be made a responsibility of
the coordinator of the licensing body, with a view to feeding this information back into
the licensing process. Information provided by proponents should be tabulated as
public data and accessible to researchers in a convenient form - possibly as a web
site. This would be of national and international interest. Furthermore annual or
biennial reports should be produced to summarise developments over the first six to
eight years at least, in order to report state-wide statistics and to draw conclusions on
issues that may affect sustainability of ASR operations and the achievement of
licensing objectives.
8.5. Accreditation of ASR installers and operators
Recognising that a wide range of skills are required for planning, designing,
constructing, commissioning and operating a successful ASR project, it is suggested
that consideration be given to the accreditation of ASR installers and operators. This
could recognise attendance at accredited training programs, such as those offered by
Centre for Groundwater Studies (with staff of DWR, CSIRO and Flinders University),
and be reinforced by audits on the performance and compliance of projects with
respect to the guidelines.
8.6. Maintenance of Government technical expertise in ASR
There will be an ongoing need for maintenance of ASR technical expertise in
government, in order to overview ASR licensing and to assist with trouble-shooting
when problems occur. It is therefore appropriate for DWR to play a role in future ASR
projects of a novel nature, - including those in different aquifer types or using different
water types. An ongoing role for DWR in partnership with CSIRO in the operation of
innovative ASR projects, is recommended. This can also be justified in terms of
widening the scope of projects that could be approved, thereby progressing
opportunities identified in the State Water Plan and under the Integrated Water
Strategy.
8.7. Mapping of ASR potential
Apart from the Adelaide metropolitan area, there has been limited mapping of areas
in this State that are potentially suitable for ASR (Gerges, 1996-Tertiary; Pavelic et al
1992- upper Quaternary). Priorities deduced from the State Water Plan and this
report can indicate the most prospective areas for the augmentation of water
resources. The preparation of strip maps along regional supply pipelines, together
with maps of water-short areas near towns, mines and irrigation areas, would allow a
strategic approach to be developed for investments in schemes aimed at enhancing
emergency water resources and drought proofing water supplies across the State.
8.8. Energy and water
As the cost of energy increases the price of water, it will be important to assess the
energy efficiency of ASR projects from a Greenhouse Gas perspective, and to
ensure that proponents take this into account in their plans and designs.
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There is also the prospect of geothermal energy being tapped by ASR-type projects,
for example for space heating and cooling in large buildings with heat exchangers.
Consideration will need to be given to conjunctive management of aquifers for energy
and water. This may require overlaying geothermal information in future mapping
exercises where ASR water storage opportunities require assessment, particularly in
cities and towns, and near intensive livestock industries.
8.9. Storage capacity evaluation
As yet the storage capacities of aquifers in the Adelaide metropolitan area are still
unknown. Ultimately, as stormwater harvesting becomes more efficient and
reclaimed water ASR becomes established, ASR will no longer be limited by the
available surface water source but will instead be capped by the storage capacity of
the aquifer system. Projects will then compete for the remaining capacity. Decisions
will be required in allocating parts of aquifers for the storage of different qualities of
water, such as mains-quality water (for emergency potable supplies), stormwater and
reclaimed water. The costs and value of each of these, and the degree to which
these are mutually exclusive, or sequential uses, have yet to be determined. Hence
it is recommended that, from a strategic perspective, an evaluation of storage
capacity for ASR systems in the aquifers in the St Vincent Basin is warranted.
8.10. Aquifer rehabilitation
Ultimately ASR involving stormwater can flush brackish urban aquifers and present
the opportunity to upgrade the beneficial use status of those aquifers. While it is not
proposed that water recovered from an injection well would meet potable standards,
it is highly likely that groundwater drawn from separate recovery wells could be
potable. Such value-adding may be substantial and could result in the development
of strategies for flushing extensive contiguous segments within aquifers. It is
therefore recommended that additional research be undertaken involving several
stormwater ASR sites, to assess the potability of groundwater with respect to the
distribution of salinity and stormwater contaminants in the region around the ASR
sites. This would be done with a view to developing an aquifer rehabilitation strategy.
It is anticipated that the value of a potable supply will be at least double the value of
an irrigation supply, and will expand options for water management in SA.
8.11. Communications
ASR has been the cause of a continuous stream of visitors to South Australia.
Already there have been two national short courses on ASR in Adelaide, in October
1996 and October 1999. The 4th International Symposium on Artificial Recharge will
be held in Adelaide 22-26 September 2002, and was secured largely on the basis of
the innovative and scientifically-founded ASR undertaken in and near Adelaide. Co-
located with this will be a UNESCO/IAEA short course on uses of isotopes to
evaluate recharge enhancement in arid and semi arid areas. (20-21Sept 2002).
ISAR4 will also provide the 3rd meeting of IAH-MAR the International Association of
Hydrogeologists Working Group on Management of Aquifer Recharge (soon to
become a Commission). There will also be a meeting of the AWWARF project group
that is based in four countries. These present opportunities to consolidate and
convey Australian research findings, to demonstrate our experience, and to share
these in a national and international audience. It also gives us exposure to the
developments occurring overseas, for example a new 200 ML/day recharge
enhancement project in California, the advances in bank filtration being made in
Europe, and to learn from the cream of international researchers on subsurface
processes affecting the utility of recharge enhancement. Allocation of some staff
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time to preparing communication materials would reap instant rewards and save staff
time later in dealing with enquiries that the conference is bound to generate.
With these materials and some training of multi-lingual staff of local eco-tourism
bureaux, the stream of future visitors could generate tourism revenue, create kudos
for the state and have minimal impact on DWR staff time.
9. RECOMMENDATIONS
9.1. Licensing procedures to be streamlined
It is recommended that a streamlined ASR approval process be established with a
single point of contact and that there be close coordination between departments,
boards and councils involved in decision making.
It is further recommended that the Department for Water Resources takes
responsibility for this coordination.
9.2. Monitoring and reporting of ASR projects
It is recommended that the Department for Water Resources establish a public data
base, ideally on the web, for receipt of (annual) monitoring reports in accordance with
licence conditions. The Department is to be responsible for evaluating reports, and
consequently for recommending changes to licence conditions, and the accreditation
status of installers and operators of ASR sites.
9.3. Accreditation of ASR installers and operators
It is recommended that the Department establish an accreditation program for ASR
installers and operators, based on attendance at training programs and on feedback
from monitoring sites established or operated by them.
9.4. Mapping ASR potential in SA
It is recommended that the Department for Water Resources performs a technical
and economic evaluation of the potential for ASR across the state, in accordance
with needs for increased supplies, improved quality of water and increased security
of supply. This work should be done in sufficient detail to produce a list of potential
projects to assist regional development initiatives. The potential projects are to
clearly indicate expected benefits and costs.
9.5. Continued public sector investment in innovation in ASR pilot
projects
It is recommended that further investigations be undertaken in a number of key
strategic areas of ASR. These investigations should include determining the ASR
storage capacity for the Adelaide metropolitan area, developing aquifer rehabilitation
strategies, establishing demonstration projects for domestic scale stormwater ASR,
continuing the development of reclaimed water ASR, advancing mains water ASR
where appropriate, evaluating opportunities for use of aquifers for energy and water
(conjunctively), extending the types of aquifers (to unconsolidated sedimentary
systems), wells (screened wells with jets in gravel packs), waters (various pre-
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treatments and mains water), and applications (saline intrusion barriers, land
subsidence mitigation, wetland protection).
It is recommended that further research necessary to underpin policies that lead to
continuous improvement in ASR practices be undertaken. It is recommended that
such research interfaces with integrated water management research and embraces
the novel aspects of innovative projects.
9.6. Guidelines
It is recommended that technical and administrative guidelines for ASR with
stormwater be finalised as soon as possible and that the technical guidelines are
submitted to national and international review with a view to standardising Australian
practice. Further guidelines on reclaimed water ASR and domestic scale ASR should
be prepared as soon as adequate information is available.
9.7. Education
It is recommended that an education program be established (web page, brochures,
training events, open days) for ASR owners and operators and for CMWB's and local
government on domestic rainwater, large scale stormwater, and reclaimed water
projects. The Department may also consider contributing to eco-tours of ASR
projects and other innovative water management projects in SA involving schools
and community, national and international delegations. These may also serve as
marketing opportunities for SA expertise in water management.
10. CONCLUSIONS
ASR is practiced in many countries throughout the world and generally to address
issues associated with potable water supplies. Consequently, the water that is stored
in the aquifer systems is treated to potable standards before injection. As reduced
quality places more pressure on Adelaide’s traditional water supply sources such as
the River Murray and the Mount Lofty Ranges, one of the risks faced in continuing to
inject low quality waters into our existing aquifers is that it limits future opportunities
to use groundwater as a least cost option to augment existing potable water
supplies.
South Australians are becoming increasingly aware of the need to conserve and
reuse our available water resources more effectively in order to maintain a balance
between environmental needs, social well being and economic needs.
In South Australia, an increasing amount of stress is being placed on surface and
groundwater resources by expanding urban populations, and expanding irrigated
horticultural areas. The impacts of this demand on groundwater are showing in the
long-term downward trends of water levels in major aquifers and the decrease in
groundwater quality. ASR has the potential to capture largely unused surface water
resources, including urban stormwater runoff, and relieve the pressure on
groundwater resources. There is little doubt now that the conjunctive use of surface
and underground water resources is critical to the optimal development of rural and
urban populations. In many cases, serious consideration is being given to the need to
reuse our available water resources more than once before summarily treating and
discharging them into the coastal marine waters. In the broader sense, the
opportunity exists to use ASR to rethink our traditional water management and
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distribution policies, and to provide cost-effective and innovative alternatives to
current methods.
The current state of groundwater recharge enhancement in South Australia has been
presented together with a series of issues and recommendations, which provide a
basis through which to:
• protect and enhance our water resources, and thereby fulfil the State Water
Plan,
• streamline and better integrate water administrative procedures,
• appropriately monitor and report on existing and new ASR operations,
• encourage appropriate investment in innovative water management,
• map the potential for ASR in places where it has most strategic potential,
• evaluate the storage capacity of Adelaide's aquifers for ASR,
• ensure technical competencies are retained in state government,
• enable the range of aquifers and water types used for ASR to expand
according to need,
• facilitate continuous improvement of ASR technology, where SA is currently a
world leader,
• encourage the industry forwards with an accreditation program and,
• capitalise on the leadership developed in SA for national and international
markets.
11. ACKNOWLEDGEMENTS
In conclusion, the authors acknowledge the commitment of the South Australian
Government through the Department of Mines and Energy, the Department of
Environment and Natural Resources, and now the Department for Water Resources
to the development of the ASR concepts, the conduct of research and investigations
with partner organisations, and the implementation and management of operating
projects over a period of ten years. Without such an investment of effort it would not
be possible for ASR to have developed to a viable water resources management tool
in this state. Local Government, especially Salisbury Council has championed the
implementation of a number of operational ASR sites. Other government agencies
SA Water, the Major Projects Group from within DAIS, the Environmental Protection
Agency and the SA Health Commission have all contributed to the body of
knowledge concerning ASR applications. Industry partners such as United Water and
Hickenbotham Homes have also played a vital role in the development and
implementation of ASR in South Australia.
The authors particularly acknowledge the contributions of the late Dr Keith Miles (a
former hydrogeologist and director of Department for Mines and Energy who
proposed a grid of ASR wells for the Adelaide metropolitan area in 1952), Mr Reg
Shepherd (who commissioned the first injection well trials on the Northern Adelaide
Plains), Mr Don Armstrong (his successor who has advanced ASR to an operational
project stage), and Mr Bryan Harris (who has chaired the Bolivar ASR Steering
Committee and the CGS where much of the research was undertaken). We would
also like to recognise the scientific and technical contributions of our peers, Dr Nabil
Gerges, Mr Zac Sibenaler, Mr Kevin Dennis, Mr Paul Pavelic (CSIRO), Mr Steven
Howles and the many technical staff who have worked on various ASR projects. The
SA Artificial Recharge Coordinating Committee chairs have been; Mr Zac Sibenaler,
Mr Steve Barnett, and Mr Russell Martin.
Page 60 of 62
The Department for Water Resources was the winner of the Australian Water
Association's National Environment Award 2000 for its outstanding work in
developing Aquifer Storage and Recovery.
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