Background
2.1
This chapter provides a synopsis of Australia's underground water
systems, including the Great Artesian Basin and the Murray-Darling Basin. It
outlines Australia's major water users by industry, including a breakdown of
water used by the mining industry by state/territory, and concludes with a
discussion of the different methods of water extraction by various extractive
industries.
Australia's underground water systems
2.2
Water is one of Australia's most precious resources.[1]
Water shortages have the potential to constrain the future economic growth of
Australia, given that Australia has the lowest average rainfall of any
continent and is the driest continent with permanent inhabitants.[2]
Predictions from the Bureau of Meteorology and CSIRO suggest that rainfall may
increase in the future but will be confined largely to intense rainfall events.
This could impact the recharge rates of underground water sources because more
rainwater will be lost to evaporation.[3]
2.3
Groundwater lies in the sandstone layers trapped between impervious
rocks or clays sitting beneath the surface. Artesian water can be drawn to the
surface through bores because of the considerable pressure under which it is
placed in artesian basins.[4]
Most of the water in the artesian basins stretching across Australia is
millions of years old and, in some cases, too salty for human consumption,
though it can still be used for sheep and cattle and to water crops.[5]
Some of these ancient sources of water are not regularly replenished by rainfall.[6]
2.4
The aquifers stretching across the country are located at different
levels and may overlay other aquifers (see Figure 2.1). Australia's largest
underground water systems include the:
-
Great Artesian Basin (in Queensland, the Northern Territory, South
Australia and New South Wales);
-
Canning Basin (in Western Australia);
-
Daly-Wiso-Georgina Basin (in the Northern Territory and
Queensland); and
-
Murray Basin (in Victoria, South Australia and New South Wales).[7]
Figure
2.1: Groundwater provinces across Australia[8]
Source: Australian Bureau of Meteorology
2.5
The Conservation Council of South Australia argued in its submission
that many water systems are currently 'under significant pressures from water
use and consumption'.[9]
Because of their significance for human consumption and agriculture, recent
programs for two systems, the Great Artesian Basin and the Murray-Darling Basin
(which includes the Murray Basin), have attempted to address reduced water
supply through government intervention.
Great Artesian Basin
2.6
The Great Artesian Basin is a multi-layered system of aquifers that
covers around a fifth of Australia.[10]
It is 'one of Australia's most essential water supplies' and contains 65
million gigalitres of water.[11]
The Great Artesian Basin is the major, in some instances the only, reliable
source of water for 180,000 people spread across 120 towns, communities and
pastoral enterprises in the arid areas of Queensland, the Northern Territory,
South Australia and New South Wales (see Figure 2.2).[12]
Figure 2.2: Map of the Great Artesian Basin[13]
Source: Department of
Agriculture and Water Resources
2.7
Declining pressure and reduced flows led in the twentieth century to
almost half of the artesian springs from the Great Artesian Basin drying up,
and many bores stopped flowing altogether.[14]
Since the 1970s and 1980s, governments have engaged in and encouraged
rehabilitation work on bores and bore drains, leading to the Great Artesian
Basin Sustainability Initiative (2000–2017) between the Australian, New South
Wales, South Australian and Queensland governments. In recent years, there has
been significant pressure recovery in a number of areas due to these
initiatives, with an estimated annual water savings of more than 250,000 ML per
year.[15]
Murray-Darling Basin
2.8
The Murray-Darling Basin is a drainage area consisting of thousands of
interconnected creeks and rivers flowing above a complex system of groundwater
and aquifers, including the Murray Basin.[16]
The northern part of the Murray-Darling Basin overlies the southern part of the
Great Artesian Basin.[17]
2.9
Although the area covers only 14 per cent of Australia, it includes more
than 40 per cent of Australia's farms and is Australia's most important
agricultural region (see Figure 2.3).[18]
Most groundwater used in the area is taken from shallow aquifers.[19]
Because of the extent of water extraction in the region, the Murray-Darling
Basin has been subject to coordinated initiatives since 2012 by the Australian,
South Australian, Victorian, New South Wales, Queensland and Australian Capital
Territory governments to reduce water use through the Murray-Darling Basin
Plan.[20]
Figure 2.3: Map of
the Murray-Darling Basin[21]
Source: Murray-Darling Basin
Authority
Australia's water users
2.10
Water is used for human, animal and plant consumption, and plays an
important role in Aboriginal cosmologies tied to the land. Native flora and
fauna throughout Australia are dependent on access to regular water, with some
groundwater-dependent ecosystems such as rivers, wetlands and springs dependent
entirely on groundwater that has been discharged to the surface. Groundwater
ecosystems existing below the surface also rely on subterranean water, and may
include stygofauna and microbial communities.
Human and
agricultural consumption
2.11
Groundwater comprises around 17 per cent of Australia's accessible water
resources. About 30 per cent of Australia's total water use is taken from
groundwater, with some regions more reliant on groundwater than others (see Figure
2.4).[22]
Figure 2.4:
Total Australian groundwater extraction, 2016–17[23]
Source: Australian Bureau of Meteorology
2.12
Across many regional, remote and arid areas of Australia, groundwater is
the main or only source of water for human consumption, stock use and
irrigation because of low or unreliable annual rainfall averages. Groundwater
is essential for the survival of communities in these areas, including remote
Aboriginal communities.[24]
For example, 90 per cent of the Northern Territory's consumptive water supplies
are drawn from groundwater, with the towns of Alice Springs and Tennant Creek
relying completely on groundwater.[25]
2.13
In 2015–16, approximately 76,544 GL of water was extracted around
Australia. The Australian Bureau of Statistics reported that total water
consumption by households and industry was 16,132 GL, a decrease of 7.2 per
cent compared to 2014–15, largely because of reductions in agricultural
consumption in New South Wales and Victoria.[26]
2.14
Most water (58.5 per cent) is used by the agricultural industry, with
household use accounting for 11.8 per cent and mining accounting for 4.1 per
cent of Australia's total water consumption. Agriculture is the primary user of
water in all states and territories except the Australian Capital Territory,
where water consumption is dominated by households (see Figure 2.5 and Figure
2.6).[27]
Figure 2.5: Australia's total water consumption by industry,
2015–16[28]
Source: Australian Bureau of
Statistics
Figure 2.6: Water use by the mining industry by
state/territory, 2015–16[29]
Source: Australian Bureau of
Statistics
2.15
The Australian Petroleum Production and Exploration Association (APPEA)
emphasised that the oil and gas industry is a relatively small user of water
compared with other industries. Dr Malcolm Roberts, APPEA's Chief Executive
Officer, asserted that agriculture 'uses more water in Australia in a single
day than the industry uses in an entire year. Manufacturing uses 22 times more
water than the gas industry'.[30]
2.16
The Minerals Council of Australia argued that 'it is important to note
the minerals industry often uses water not suitable for other industrial
purposes, including saline and hypersaline water'.[31]
The International Association of Hydrogeologists emphasised the mining
industry's relative value for money proportional to its total water use.[32]
This was echoed by APPEA, who contended that the oil and gas industry's water
consumption represented 'exceptionally high economic value-add' compared with
other industries.[33]
2.17
However, the Committee also heard from other submitters and witnesses
that figures of water use did not necessarily equate to decreased impacts in
comparison with other industries. Ms Georgina Woods from Lock the Gate Alliance
suggested that estimates of overall water usage by the mining industry did not
give an adequate picture of intensive use in small areas:
In the Hunter region, for example, the mining industry owns
more than half of the high-security water licences in the regulated river and
is a big groundwater user, particularly in the porous-rock aquifers. The Great
Artesian Basin is another example of a water resource that has a significant
and growing water use by the mining industry.[34]
2.18
Ms Joanne Rea, the Chair of Property Rights Australia, argued that
agricultural use of water 'is necessarily estimated, always overstated and has
more to do with the capacity of bores than actual usage'. She contended that
although agriculture may use a significant amount of water, its impacts are
spread across 'a wide area so that local impacts are minimal or manageable'.[35]
The issue of impacts is further discussed in Chapter 4.
2.19
The Committee was told that competition for water resources between
different industries may intensify in the future because of anticipated impacts
on rainfall from climate change. The Nature Conservation Council of NSW argued
in its submission that the:
Conflict between extractive industry's use of water resources
and other users is likely to become more acute as the effects of climate change
are felt in Southern Australia, with less water available for all users and for
the environment.[36]
Importance of water in Aboriginal
cosmologies
2.20
Many remote Aboriginal communities depend entirely on springs sourced
from groundwater.[37]
However, water, for some traditional owner groups, is important not just as a
resource but also because of the cultural and spiritual meanings attached to
particular waterways, natural catchment areas and the land.[38]
In some instances, sacred sites for traditional owners extend beneath the
surface of the earth and may include underground water.[39]
2.21
Miss Helen Bishop, in a submission prepared on behalf of the traditional
owners of the area where the Rum Jungle abandoned uranium mine is located,
stated that:
Several significant and sacred sites are located in the area
which holds significant relevance to Koongurrukun and Warai people in bestowing
and maintaining Mookununggunuk [epistemology] that maintains the knowledge of
life for the area...
The importance of best practice rehabilitation and successful
implementation of the rehabilitation plan are paramount to the maintenance of
Mookununggunuk, in particular the sacred sites identified within the
rehabilitation areas. These sites hold significant cultural values directly
connected to underground water.[40]
2.22
The importance of water to Aboriginal identity was raised during the Northern
Territory Government's Scientific Inquiry into Hydraulic Fracturing in the
Northern Territory. The final report noted the centrality of water to
Aboriginal identity:
Water is an essential part of traditional Aboriginal culture,
both in terms of access for survival for groups living in remote areas, and
also in terms of its spiritual link to Aboriginal sacred sites and religious
customs.[41]
2.23
The Aboriginal Fracking Forum stated that:
We are concerned about the damage to our water, our country,
our dreaming and our songlines. This damage would be irreversible...Drilling in
one area has a bigger impact than just that place. It will damage neighbouring
language groups on country and the entire water system...People and country are
one and the same, any damage to our country impacts us, our identity and who we
are.[42]
2.24
The issue of how regulatory frameworks address water rights for
Traditional Owners is addressed in Chapter 3, while impacts specific to
Traditional Owners are outlined in Chapter 4.
Groundwater-dependent ecosystems
2.25
Groundwater-dependent ecosystems rely on groundwater for some or all of
their water requirements, whether directly or indirectly. These may include
surface water ecosystems such as wetlands and rivers that rely on the surface
expression of groundwater; terrestrial fauna and flora; terrestrial ecosystems
dependent on subsurface groundwater; and subterranean ecosystems, such as
aquifer and cave ecosystems.[43]
2.26
Some flora and fauna species that rely on artesian springs are listed as
endangered species and communities, notably in areas lying above the Great
Artesian Basin.[44]
Several submitters argued that there is very little knowledge about local flora
and fauna and how groundwater might interact with these species in some areas,
including very remote regions where relatively little research has been
conducted.[45]
2.27
The Committee heard evidence from an expert in groundwater ecosystems,
Associate Professor Grant Hose, outlining the importance of water for
ecosystems that live entirely underground, and how the organisms, stygofauna
and microbes that live in aquifers contribute to the composition and quality of
the aquifers' water. Professor Hose commented:
The biodiversity and the ecological functions, the importance
of what lives in aquifers, is all too frequently overlooked. It does have
immense value, just as we can go out on the street and quantify what a tree
does; we can understand what that tree does and how important that tree is to
the global environment...[O]rganisms in groundwater...have a similar function in
making the environment better...Their capacity to do that is important, because
it provides us with clean drinking water. It also supports the movement of
water through aquifers. What lives in aquifers is important to the quality and
the availability of water that's in there.[46]
2.28
Groundwater ecosystems, or ecosystems living entirely in water systems
below ground, contribute to water quality by breaking down pollutants,
purifying groundwater so that it is fit for consumption, and contributing to
the storage and flow of water through aquifers. Stygofauna—the invertebrates
that live in groundwater—are especially diverse in Australia. Few are listed as
threatened species or members of threatened ecological communities, despite
their rarity, because of the relatively recent recognition of their
significance and difficulties associated with developing stygofauna taxonomy.[47]
The Western Australian Government recognises the global significance of
stygofauna; the Queensland Government has released guidelines for the
assessment of stygofauna; and the New South Wales Government has risk
assessment guidelines for groundwater-dependent ecosystems.[48]
Methods of water use by the extractive industry
2.29
The amount of water extracted and methods of extraction employed by the
extraction industry depend on the type of material being extracted, as well as
local geography and geology.
2.30
As noted above, the mining industry as a whole was responsible for 4.1
per cent of Australia's total water consumption in 2015–16. Metal ore mining
accounts for more than half of the mining industry's total water use (2.6 per
cent of Australia's total water consumption), followed by coal mining (Figure
2.7).
Figure 2.7: Water use by mining
sectors as a proportion of total water use,
2015–16[49]
Source: Australian Bureau of Statistics
2.31
Water use in the mining industry may differ in a number of aspects from
water use in the oil and gas industry, as outlined below.
Water use by the mining industry
2.32
The mining industry utilises water in various ways before, during and
after mining operations. The New South Wales Minerals Council outlined types of
water take by mining companies that require water licenses, including: water
that is extracted, is dewatered, is required for processing or washing, is
required for dust suppression or water that flows into a void post-mining.[50]
2.33
The Queensland Department of Environment and Heritage Protection set out
a definition of 'mine-affected water' that includes the following:
-
groundwater from a mine's dewatering activities;
-
mine pit water, tailings dam water, processing plant water;
-
rainfall runoff which has been in contact with areas disturbed by
mining activities (excluding rehabilitated areas); and
-
groundwater which has been in contact with any areas disturbed by
mining activities which have not yet been rehabilitated.[51]
Dewatering of mines operating below
the water table
2.34
For mines operating at depths below the natural water table, water is
extracted in a process called dewatering to allow mining to occur safely.[52]
This water is removed via dewatering wells adjacent to the mine void. The
Minerals Council of Australia noted in its submission that water extracted in
this way may be used for operational purposes (such as minerals processing),
and may either be managed onsite, or discharged where an operation has a
license that allows this.[53]
2.35
Mining below the water table can result in final pit voids being left in
the landscape after mining activities have ceased, with pit lakes forming once
dewatering is no longer occurring. Geoscience Australia stated that this
process can result in permanent changes to the local water table due to
evaporative loss from pit lakes, as shown in Figure 2.8.
Figure 2.8: Schematic diagram showing impacts of dewatering
and final pit voids[54]
Source: Geoscience Australia
Management of mine-affected and
process water
2.36
In many cases, mine-affected water requires active management and cannot
simply be released into the surrounding environment. This includes water used
in minerals processing procedures (often referred to as process water),
for example to wash and prepare coal extracted in coal mining operations.[55]
Processing uranium from its raw form into usable end product also involves
significant water use.[56]
2.37
Management of mine-affected water is dealt with in various ways by the
mining industry, depending on the type of water and the level of impact or
contamination. The Minerals Council of Australia pointed to several examples of
mines in Australia implementing specific measures to deal with mine-affected
and process water, including:
-
construction of a reverse osmosis water treatment plant at a coal
mine in Queensland's Fitzroy Basin, to reduce the amount of mine-affected water
held onsite to allow water treated in the plant to be used for other parts of
the mining operations; and
-
construction of a brine concentrator at the Ranger Uranium mine,
which allows process water from the mine's tailings storage facility to be
treated and discharged.[57]
Accounting for water use by the
minerals industry
2.38
The Minerals Council of Australia discussed how the mining industry
describes and accounts for its water use across the industry. It drew the Committee’s
attention to the Minerals Council of Australia Water Accounting Framework
which, it stated, 'is widely considered international best practice in
accounting'. It explained the purpose of the Water Accounting Framework as
follows:
The framework enables water flows to be accounted for and
quantified by source and destination through an input-output model. Standard definitions
for both water 'source' and 'destination' categories create uniformity between
companies and hence across the sector in how water quality, quantity and
purpose is described. Agreed categories also describe the 'level of treatment
effort' required to achieve a standard of water quality fit for human
consumption. While indicative only and not reflective of end uses, this process
supports benchmarking and continuous improvement.[58]
Water use by the oil and gas
industry
2.39
The oil and gas industry in Australia incorporates the extraction of
various petroleum products, including petroleum liquids (crude oil, condensate
and liquid petroleum gas) as well as natural gas products.
2.40
Conventional gas extraction involves the drilling of wells to extract
natural gas located in permeable material beneath impermeable rock. The gas is
generally located in relatively large reservoirs and can be extracted via
vertically drilled wells. Unconventional natural gas is located in less
permeable rock or spread more diffusely throughout a deposit. Forms of
'unconventional' gas include coal seam gas (natural gas located within coal
seams), shale gas (located in shale rock formations) and tight gas (located
within low permeability sandstone rock). Extraction of unconventional gas
requires additional extractive processes.
2.41
APPEA's overview of how water is used in extractive oil and gas
projects is summarised below. It noted that water use varies in each stage of
the project life (exploration, development and production) and is different for
different project types.[59]
Water used in well drilling
2.42
Water is a component of the drilling muds used for well drilling, with
the amount of water used depending on how many times the mud is reused in
different wells and the lifetime production of each well. APPEA stated that in
Australia, 'the general rule of thumb for onshore wells is approximately 1 ML
per well for drilling'.[60]
Water found in oil and gas reserves
brought to the surface during extractive processes
2.43
Oil and gas extraction also involves bringing to the surface water that
is present alongside the targeted resource. This water is called produced
formation water (PFW) or, in coal seam gas operations, associated water.[61]
APPEA noted that PFW is made up of various components and 'may include
petroleum hydrocarbons, suspended solids, dissolved oxygen and salts'. It noted
further that the volume and properties of PFW vary from location to location
and over the productive life of a reservoir.[62]
2.44
APPEA explained how associated water is extracted in coal seam gas
operations:
[Coal seam gas] is absorbed into the coal matrix and is held
in place by the pressure of formation water. To extract the gas, a well is
drilled into the coal seam and formation water from the coal cleats and
fractures is pumped and withdrawn. The removal of water in the coal seam
reduces the pressure, enabling the CSG (coal seam gas) to be released
(desorbed) from the coal micropores and cleats, and allowing the gas and
'produced water' to be carried to the surface.[63]
2.45
APPEA commented further that the volume of associated water and the
amount of gas produced depend on the particular geological and hydrogeological
features of a location:
No two wells or coal seams behave identically and associated
water production can vary from a few thousand to hundreds of thousands of
litres a day, depending on the underground water pressures and geology. A well
will deliver most of its water at the start of the pumping phase. As the water
is pumped from the coal formation, the pressure is released from the seam, and
the gas begins to flow.
Associated water production and gas production are inversely
proportional. As water rates decline, gas production increases...
Coals with lower permeability do not require as much water to
be pumped to reduce the pressure on the coal. This is why some operations –for
example in NSW and Queensland's Bowen Basin – produce lower volumes of water.
Areas with higher permeability generally produce higher volumes of water.
Different CSG operations produce differing amounts of water.[64]
2.46
APPEA noted that associated water extracted during coal seam gas
operations can be treated and used in a range of different ways once brought to
the surface, including:
-
industrial reuse (for example, using associated water as cooling
water for industrial projects which would otherwise have taken water from local
streams or groundwater);
-
agricultural reuse (for example, crop irrigation), reducing the
need to extract water from local aquifers;
-
injection of associated water back into local aquifers,
increasing the volume of water stored in these aquifers; and
-
river discharge—blending associated water with seasonal
non-permanent streams.[65]
Water used in hydraulic fracturing
(fracking)
2.47
Water is a major component of hydraulic fracturing (or fracking).
Hydraulic fracturing involves pumping fluid at high pressure down a wellbore to
initiate and encourage cracks in low permeability rock to recover gas and oil.
This fluid contains water, sand or other solids and chemicals.[66]
Moratoria and bans on particular
forms of gas extraction
2.48
Queensland and New South Wales are the only states in Australia where
coal seam gas extraction is currently being undertaken, while other
unconventional gas extraction involving fracking processes occurs in northeast
South Australia.[67]
2.49
Victoria, Tasmania and Western Australia have moratoriums in place on
hydraulic fracturing activities, while the Northern Territory Government has
recently announced a decision to lift a moratorium on fracking previously in
place.[68]
The South Australian Government has proposed a ten-year moratorium on fracking
activities in the Limestone Coast area of the state's southeast.[69]
Conclusion
2.50
This chapter has outlined the background to Australia's underground
water systems, major water users and how extractive industries take and use
water. The following chapter outlines the regulatory frameworks governing water
use.
Navigation: Previous Page | Contents | Next Page