Download Western Australia Water Policy Issues in Climate Uncertainty (Report)

WESTERN AUSTRALIA:
WATER POLICY ISSUES IN
CLIMATE UNCERTAINTY
Copyright by
AUSTRALIAN ACADEMY OF TECHNOLOGICAL SCIENCES
AND ENGINEERING
2005
The Academy is not responsible, as a body,
for the facts and opinions advanced in any of its publications
ISBN 1 875618 85 6
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Email: [email protected]
email: [email protected]
Index
Introduction ...............................................................................................................................1
Climate uncertainty ................................................................................................................... 1
Water sources in the South West ................................................................................................3
Dams .........................................................................................................................................3
Groundwater ..............................................................................................................................4
The Perth Basin ......................................................................................................................4
Hydrogeology in Government .................................................................................................5
The Yarragadee aquifer ............................................................................................................6
Groundwater outside the Perth area ........................................................................................ 7
Seawater desalination .................................................................................................................8
Environmental water ..................................................................................................................8
Pipeline or canal from the Kimberley ......................................................................................... 8
Water-saving measures................................................................................................................9
Water pricing and trading .......................................................................................................... 9
Economic, environmental, and social aspects .............................................................................10
Conclusions and recommendations ............................................................................................11
Conclusions.............................................................................................................................11
Recommendations ...................................................................................................................12
APPENDICES - PAPERS PRESENTED AT THE SYMPOSIUM ..........................................14
THE PAST, PRESENT AND FUTURE FOR WATER MANAGEMENT IN (SW)WA ....... 14
WATER – THE NEXT GENERATION OF CHANGE .........................................................17
ISSUES ARISING FROM INTER-REGIONAL TRANSFERS ..............................................18
POLICY ISSUES AND APPROACHES ...................................................................................18
THE SOUTH WEST YARRAGADEE AQUIFER .................................................................. 20
MANAGED AQUIFER RECHARGE ON THE SWAN COASTAL PLAIN .........................21
COMMUNITY ATTITUDES TOWARD WATER USE AND WATER PRICING ..............22
WATER POLICY CHALLENGES IN AN ENVIRONMENT OF UNCERTAINTY ........... 22
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WESTERN AUSTRALIA: WATER POLICY ISSUES
IN CLIMATE UNCERTAINTY
compiled by
Phillip E Playford
[email protected]
Introduction
A one-day symposium to consider Western Australian water policy issues in climate uncertainty was held in Perth on 14 October 2005, sponsored by the Australian Academy of Technological Sciences and Engineering, the Australian Water Association, and Engineers Australia.
The symposium was attended by 155 people. Papers were presented successively by Mr
Brian Sadler, Dr Don Blackmore, Mr Harry Ventriss, Mr Phil Commander, Dr Simon Toze, Dr
Geoff Syme, and Professor Aynsley Kellow. Abstracts of those papers are attached as appendices to this report.
An invited expert panel made brief presentations of their views on relevant issues and
responded to questions from participants. Members of this panel were Dr Bernard Bowen,
Professor Jorg Imberger, Professor Aynsley Kellow, Dr Paul McLeod, Dr Phillip Playford, and
Mr Barry Sanders. Phillip Playford was invited to prepare this report in consultation with other
panel members, based on material presented at the symposium by speakers, the panel, and the
audience.
Climate uncertainty
It is clear that Western Australia is experiencing a time of climate uncertainty; there is no
consensus in predicting the future climate of this area in the short to medium term. No one
can be sure whether that climate will become dryer or wetter than now, or how the rainfall will
be distributed. However, we do know that a decline in rainfall in the South West, amounting to
about 10% of the long-term average, has been experienced during the past 30 years, resulting
in about 50% less runoff into dams in the Darling Range. This has been a matter of considerable concern to Government and the public.
It is uncertain whether this reduced rainfall level will continue, decline even further, or be
reversed in the short to medium term. Fortunately, rainfall during 2005 has been a little above
the annual average, resulting in more runoff into the dams, so that water storage has risen from
about 25% of capacity in May 2005 to more than 40% in early November 2005, the highest
level in the past five years.
There can be little or no doubt that ambient surface air temperatures around the world have
risen during the past 30 years and some computer modelling has linked that rise with declining
rainfall in south-western Australia. As a result, some authorities have made dire predictions
regarding the future of Perth water supplies and agriculture in the South West. On the other
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hand, some scientists are sceptical about the validity of the computer modelling, maintaining
that controls on world and local climate are so complex that they cannot be modelled reliably
at present. They point out that the climate of the South West may change at any time because
of factors that are little understood at present, such as variations in oceanic circulation and
radiation from the sun. Moreover, such variations could result in increased rather than decreased rainfall.
The other issue that is currently being debated is the role of anthropomorphic ‘greenhouse’ gases, primarily CO2 and methane, in causing increased surface temperatures around
the world. Many scientists attribute the recent global temperature rise to the steady increase
that has occurred in those gases in the atmosphere as a result of human activities, beginning
with the industrial revolution in the 19th century. However, other scientists disagree that this is
the main cause of the temperature rise, assigning much smaller effects to those gases. They
maintain that the foremost cause of temperature change is varying heat output from the sun,
which again is little understood. Moreover, they point out that water vapour is far more significant as a greenhouse gas than either CO2 or methane.
It must be remembered that from both geological and human perspectives world climate is
always changing. There is no reason to believe that without any human influence our climate
would have remained unchanged long into the future. Some scientists claim that the changes in
climate currently being experienced globally are part of a normal cycle, essentially unrelated to
human factors.
Only 18,000 years ago, at the peak of the last glaciation, the climate in the South West was
very arid, with extremely strong prevailing winds and sea level 130 m lower than today. Thus
the greatest aridity in the South West (and the rest of Australia) in geologically recent times was
associated with the coldest temperatures. From 18,000 until about 6,000 years ago, sea level
rose very rapidly (more than 1 cm/year) as the major ice caps in the northern hemisphere
melted, and the climate in the South West became wetter and warmer. During the past 6,000
years sea level and climate have been relatively stable. Periodic changes must have occurred in
annual rainfall and temperature during this period, as is known to have occurred in the northern hemisphere, but we do not have reliable historic records for Perth before 1876, and no
significant research has been carried out on the topic. However, we do know that Aboriginal
people inhabited the South West for more than 40,000 years, including the coldest and most
arid time of the last ice age, and they were able to adapt to the changing climates.
Consequently, it is clear that Western Australian water policies need to take account of the
uncertainties that are associated with predictions on future climates. The relatively dry conditions experienced during the past three decades may or may not continue in the short to
medium term (i.e. the next few years to several decades); either wetter or dryer conditions
might prevail in the future. The worst-case scenario is that of continued decline in rainfall, and
it is appropriate to allow for this by expanding and diversifying potential sources of supply, reusing treated waste water, and promoting water conservation.
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Water sources in the South West
The dominant source of water for domestic and commercial use in Perth and the South
West is groundwater. Some 80% of the approximately 560 GL per year used in the metropolitan area of Perth and surrounding districts, from the Moore River to Mandurah, is provided by
groundwater, drawn from both unconfined and confined (artesian) aquifers. The rest comes
from dams.
Perth is unique among Australian capital cities in its reliance on groundwater. Sydney,
Melbourne, Brisbane, and Adelaide all depend on surface water and are therefore more vulnerable to any short- or long-term drying of the climate. Those other capitals are currently experiencing water-supply restrictions that are considerably more stringent than those in Perth.
There can be little doubt that Perth is in a better position in relation to future water supplies
than any other capital city in mainland Australia. Unlike those cities Perth is able to increase its
low-cost supplies through expanded groundwater production from the Perth Basin. Consequently it is surprising that serious consideration is being given to radical and expensive schemes
for bringing water from the Kimberley to Perth, and because of delays experienced in developing the South West Yarragadee aquifer Perth is to be the first city in Australia to adopt expensive and energy-intensive seawater desalination.
Dams
The main river systems draining the Darling Range have now been dammed by the
Mundaring, Canning, Serpentine, North Dandalup, South Dandalup, Wungong, Victoria, Harvey,
and Stirling reservoirs. From these dams the Water Corporation currently takes some 100 GL
a year, which meets about 40% of Perth’s domestic water needs, compared with 60% from
groundwater. Another large reservoir, Wellington Dam, provides irrigation water in the South
West, but at present it is regarded as being too saline for domestic use.
There is little remaining potential to expand this reservoir system, as most fresh-water
rivers and streams are now dammed. However, proposals have been put forward to increase
runoff into existing dams by clearing or thinning vegetation, and it may be possible to obtain
some domestic water from the Wellington Dam, if its salinity problems can be mitigated.
These measures could be expected to increase the amount of dam water available for Perth’s
needs. However, it seems clear that groundwater, rather than dams, will be the major source of
any increase in supplies.
Water demand for Perth and adjoining areas is expected to double in less than 50 years, so that
long-term planning by Government to meet the water needs for this period and beyond is
essential. Similar forward planning for regional centres in Western Australia is also very necessary.
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Groundwater
The Perth Basin
As previously mentioned, groundwater currently provides about 80% of the total water
needs for Perth and adjoining areas. Some 160 GL per year of this groundwater is used for
domestic purposes, and irrigation consumes about 300 GL per year, consisting of 200 GL
from licensed commercial bores and 100 GL from unlicensed garden bores. This groundwater
is derived from sedimentary rocks, mainly sandstone and limestone, in the Perth Basin. Domestic bores and most commercial bores tap shallow unconfined aquifers, whereas 60% of the
groundwater production by the Water Corporation for Perth’s integrated water-supply system
now comes from deep confined aquifers.
The Perth Basin is nearly 1,000 km long and up to 90 km wide, extending from the Murchison
River in the north to Augusta in the south, and east to the Darling Fault. The basin contains
very thick sedimentary rocks, including a Jurassic unit known as the Yarragadee Formation,
which includes up to 2,000 m of sandstone. The sandstone in that formation constitutes very
effective reservoirs for fresh to brackish groundwater, in both confined (artesian) and unconfined aquifers. The Yarragadee Formation and overlying aquifers in the Cretaceous Leederville
Formation and near-surface sands now supply about 60% of Perth’s household needs, mainly
from bores in the Gnangara groundwater mound, and to a much lesser extent in the Jandakot
mound.
Another important unconfined aquifer in the basin is the Tamala Limestone, a unit that
occurs along and close to the coast and on nearby islands. It is commonly overlain by quartz
sand, some of which also forms effective aquifers. Similar sand, often water bearing, blankets
the surface of much of the rest of the basin. Consequently, much of the rain falling over the
basin sinks into this sand and replenishes the underlying aquifers.
Bores used for home gardens and lawns are unlicensed, while those for other purposes
require licenses. Until very recently most commercial bores were not metered, so that there
could be no effective Government monitoring of their levels of production. Domestic bores
are unlicensed and un-metered, because recharge of the shallow aquifers by rainfall exceeds the
rate of abstraction. However, salt-water intrusion has occurred in some areas where abstraction has exceeded recharge, and it is possible that licensing and metering will eventually be
required in such areas.
Plans by the State Government for the injection of appropriately treated waste water into
shallow aquifers is welcome, subject to adequate health and cost considerations, as this could
help to prevent depletion of those aquifers. At present the water in sewers is piped offshore,
and much of the rainwater running from our roads is wasted by being piped into the Swan
River.
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Hydrogeology in Government
Exploration needed to locate groundwater for cities and towns is acknowledged to be a
Government responsibility, while the groundwater required for commercial use has to be found
by companies or individuals, and is subject to licensing by Government.
For more than 100 years, from 1888 to 1995, exploration for groundwater to supply communities throughout Western Australia was the responsibility of the Geological Survey Division of the Department of Mines (now the Department of Industry and Resources). From
1962 to 1995 the Geological Survey, as part of its role in groundwater exploration, conducted
exploratory drilling programs in the Perth Basin, from the Geraldton area in the north to near
Augusta in the south. Those programs consisted of 16 lines of deep bores and 10 exploration
areas of shallower bores (not including drilling carried out by the Metropolitan Water Authority and the Public Works Department). This strategic program was designed to determine the
regional extent in the basin of fresh water that could eventually be developed for Perth and the
South West. More than 200 deep bores were drilled, each from 500 m to 1600 m deep. The
total cost of these programs was more than $60 million (in today’s dollars).
This program showed that the Perth Basin contains very large reserves of fresh groundwater, mainly located in the Yarragadee Formation in two areas, from Perth to Dongara in the
North Yarragadee aquifer and from Bunbury to Augusta in the South West Yarragadee aquifer.
In 1994 the Geological Survey formulated plans for more intensive drilling in the South
West Yarragadee aquifer. That would have enabled the Hydrogeology Division to more adequately define the groundwater resources in that area and understand hydrogeological aspects
of the aquifers. When the Hydrogeology Division was transferred to the newly established
Water and Rivers Commission in January 1996, the Commission gave an undertaking that
hydrogeological functions previously carried out by the Geological Survey would continue as
before. Those functions included:
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groundwater exploration and resources assessment
hydrogeological mapping
maintenance of the groundwater database
preparation of a report to integrate the results of drilling in the Perth Basin from
1962 to 1995.
However, the Water and Rivers Commission did not honour this commitment. Groundwater exploration, resources assessment, and hydrogeological mapping virtually ceased, the groundwater database was not maintained (no company or private bore data were entered into the
database), and the critically important report on Perth Basin groundwater resources was not
produced. Morale among the hydrogeologists deteriorated and the group was dismembered by
transferring some of the staff to positions throughout the organization. This was at a time
when adequate information on the groundwater resources of the Perth Basin should have
been available for Government to assess its options for future water supplies.
There can be no doubt that the transfer of the hydrogeology group from the Geological
Survey to the Water and Rivers Commission was a mistake and that it had serious consequences for Perth’s water supplies, as discussed above, and for the understanding of groundwater resources across the rest of Western Australia. Whereas strategic exploration has always
5
been an essential part of the culture of the Geological Survey, it never formed part of the
water-regulatory culture of the Water and Rivers Commission. Some of these problems were
raised in the report of the Auditor General in 2003.
The incoming Gallop Government decided in 2001 to merge the Water and Rivers Commission with the Department of Environment. This move was also a mistake, as it created the
potential for conflicts of interest when assessing groundwater developments. The culture of
the Department of Environment is oriented towards environmental protection, not groundwater exploration and development.
The Government eventually recognized this situation, and in 2005 it was announced that a
new Department of Water would be established to take over responsibilities for Government
groundwater regulation, exploration, and assessment. Legislative changes have yet to be made
to authorize statutory actions in the name of the new Department.
It will be vitally important for adequate funding to be made available for this new Department to undertake strategic exploration to locate the groundwater resources needed to meet
the future water needs of Perth and regional Western Australia. It should be emphasized that
the exploratory drilling and hydrogeological research necessary to identify potential groundwater resources is distinct from the evaluation work needed to bring an untapped resource into
production. Evaluation drilling can reasonably be considered as being the responsibility of a
development proponent.
The hydrogeology section needs to be reinvigorated and given primary responsibility for
groundwater exploration and evaluation of the results obtained. Restoration of the groundwater database and publication of a comprehensive report on the hydrogeology of the Perth
Basin should be given high priority. A separate publication on the shallow aquifers used for
homes and industry in the Perth area is also warranted.
The responsibilities of the new Department in relation to those of the Water Corporation
will also need to be clearly defined, ensuring that there is adequate separation between the
powers of the regulator on the one hand and the provider on the other.
Water is a unique resource; indeed our very existence depends on wise planning for its
discovery, supply, and efficient use. This puts considerable pressure on the new Department,
together with the Water Corporation, to develop policies that are right and not just politically
correct.
The Yarragadee aquifer
Drilling for detailed assessment of the South West Yarragadee aquifer, instigated and financed by the Water Corporation, began in 2003. This was some nine years after the program
had first been proposed by the Hydrogeology Division of the Geological Survey. The new
drilling has confirmed that up to 300 GL per year of high-quality groundwater (about 200 mg/
L of total soluble solids) could be produced sustainably from aquifers in the area. Such production would be about three times what is currently obtained from dams in the Darling Range. At
this stage the Water Corporation is proposing to produce 45 GL per year from this source, to
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enter the integrated water-supply system. This is the same rate of production as that proposed
for the desalination plant, comparative costs being $0.85/kL for South West Yarragadee water
and $1.16/kL for desalination water.
It seems likely that if the results of the new drilling, first announced in 2005, had been
available two years earlier, a decision to construct a desalination plant would have been deferred, as the water needed to satisfy Perth’s expanding water needs could have been obtained
at much lower cost from the South West Yarragadee aquifer.
Some local authorities in the South West have expressed opposition to the transfer of
groundwater from the South West Yarragadee to Perth and adjoining areas. However, symposium participants felt that this opposition is not soundly based, given that other commodities,
such as electricity and gas, are moved freely from one part of the State to another. Like any
human activities, the environmental issues involved will need to be managed carefully, and it
seems likely that the Perth integrated water-supply system will eventually be extended to embrace most of the South West, including shires in the Bunbury-Augusta region.
Very large groundwater resources are also known to occur in the North Yarragadee aquifer,
in the area between Perth and Dongara, but the only evaluation drilling carried out so far has
been for Geraldton’s water supply, at the northernmost end of the aquifer near Allanooka. It is
important that other areas underlain by the aquifer be evaluated as soon as possible through
appropriate drilling, with a view to proving possible future water supplies for Perth and elsewhere. It should be noted that the water quality in this aquifer is poorer than that currently
used in Perth (Geraldton’s Yarragadee water contains about 700 mg/L TSS, compared with
about 400 mg/L for Perth’s water). However, the quality can be improved by mixing with dam
water, as is already done for water from the Gnangara and Jandakot mounds, or by mixing with
high-quality South West Yarragadee water. In any case, undiluted North Yarragadee water is
currently supplied for domestic use in Geraldton.
Another measure that should be considered is the use of reverse-osmosis desalination to
improve the quality of brackish water, such as that in Wellington Dam. That could be much
more cost effective than desalinating seawater.
Groundwater outside the Perth area
Groundwater also plays a vital role in supplying water for cities, towns, and the mining,
agricultural, and pastoral industries throughout the State. Geraldton and Bunbury are totally
dependent on groundwater, as are many of the smaller country towns. Water policies adopted
by Government are therefore very important to those places and industries.
The mining industry draws very large volumes of saline groundwater, suitable for mineral
processing, from the palaeodrainage system of ancient riverine deposits that occur through
large areas of the interior of Western Australia. Ongoing data collection, modelling, and evaluation of potential groundwater resources are required for strategic planning and managing the
future water needs of the public and industry across the State.
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Seawater desalination
A seawater desalination plant is currently being constructed at Kwinana to provide 45 GL
per year of potable water for the integrated water-supply system.
The desalination plant has been justified as a precautionary measure, based on the possibility of continued low rainfall. The plant will be energy intensive, with high operating costs.
Brine produced by the desalination process is to be piped into Cockburn Sound, and some
concern has been expressed regarding its possible effects on the marine ecosystem. However,
the Department of Environment is confident that there will be no adverse consequences.
A view was expressed at the symposium that when more low-cost water becomes available
(through development of the South West Yarragadee aquifer or increased rainfall and runoff
into dams) it should be feasible to ‘mothball’ the desalination plant, reactivating it if the need
arises.
Smaller reverse-osmosis desalination plants are already being successfully operated in a
number of country centres in Western Australia, mainly treating brackish groundwater for
domestic use.
Environmental water
The damming of a river can have seriously adverse environmental impacts downstream
from the dam, due to the diminution in water flow. There is increasing pressure around Australia for more water to be released from dams in order to promote conservation of downstream
ecosystems. This trend could impact to an increasing extent on dams in Western Australia,
thereby reducing the amount of water available for other uses. That would in turn increase the
need for water to be provided from other sources, particularly groundwater and, perhaps,
desalination.
Pipeline or canal from the Kimberley
From time to time it has been proposed that a pipeline be constructed to bring water from
the Kimberley District to Perth. Those proposals have generally been dismissed as ‘pipe dreams’
because of the high costs involved. The most recent proposal, by Tenix Pty Ltd, is for a canal,
3,700 km long, to be constructed from the Kimberley to Perth, to carry up to 200 GL a year of
fresh water. It is proposed that the water be obtained from a borefield beside the Fitzroy River
near Fitzroy Crossing.
Many scientists and engineers maintain that there are numerous economic and practical
flaws in the canal proposal. It is difficult to envisage the possibility of a high-cost canal or
pipeline from the Kimberley competing economically with more readily available water sources
in the South West. Apart from the high costs and doubtful practicalities of the canal scheme,
it is unlikely that the required volume of fresh water could be obtained from aquifers adjoining
the Fitzroy River. However, these proposals are currently being examined by a committee,
chaired by Professor Reg Appleyard, and the results can be expected in 2006.
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Water-saving measures
The State Government has made a number of directions and introduced incentives designed to conserve water and impress on consumers the critically important value of our water
resources. Most of these measures, for example restricting the use of sprinklers and providing
subsidies for water-efficient washing machines, etc, are supported by both scientists and engineers. One notable exception is the Government subsidy for installation of rainwater tanks.
Some maintain that this is a mistake, as the health risks from water in such tanks are largely
ignored, and it would be better if water from roof runoff was allowed to flow into dry wells,
from which it would recharge shallow aquifers that are utilized by home bores. Furthermore,
the use of rainwater tanks is a very expensive option, requiring about 15 years to recover
purchase and installation costs.
The policy of subsidizing the installation of home bores is generally supported. However,
it needs to be recognized that the reserves of groundwater for such bores are not limitless.
Salt-water intrusion is an increasing problem in some vulnerable areas near the Swan River and
the Indian Ocean. Careful monitoring of bores in those areas needs to be undertaken, and it
may eventually prove necessary to control the use of some home bores.
Water pricing and trading
Many scientists and engineers consider that water is undervalued by the community and
that its conservation would best be served by introducing charges for water used by industry,
expanding trading in private water rights, and raising the cost of scheme water to the public.
However, there could be considerable public opposition to such charges unless the extra income is seen to be devoted towards improving water infrastructure and discovering and proving new water sources. Moreover, if higher charges were to be levied on home users while low
charges (if any) are levied on commercial users, this could create a social backlash.
There is general agreement about the need for the Department of Water, the Water Corporation, and the private sector to provide for the maintenance and expansion of their professional capabilities, by employing and training new staff. In that way the water industry could
recover from the downsizing and outsourcing that occurred several years ago, just at a time
when water issues were becoming critically important.
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Economic, environmental, and social aspects
There is general agreement regarding the need to balance the economic, environmental,
and social aspects of any new water-development proposals. However, some scientists and
engineers feel that in certain cases undue emphasis has been placed on environmental issues,
and that economic and social factors have not always been given adequate consideration.
It must be acknowledged that any significant human activity will have consequences for the
environment. No one disputes the need for adequate environmental analysis of development
proposals, but the other two components of the ‘triple bottom line’ also need due consideration. It is clear that some groundwater, dam, and desalination developments will have adverse
effects on the environment, to varying degrees. However, economic and social values of a
proposed project may outweigh the adverse environmental consequences, and if so, the project
should be allowed to proceed, while taking measures to minimize any adverse environmental
changes.
An example is that of the Gnangara groundwater project. There can be little doubt that the
advantages to the community of developing this groundwater mound have greatly outweighed
any adverse environmental consequences. Groundwater extraction from the shallow aquifers
has contributed, in conjunction with climate change, to lowering the local water table, altering
the ecology of the area so that the vegetation has changed from a wetland to a dryland flora.
This could be regarded by some as being a poor environmental outcome, even though the
adverse environmental effects are not nearly as great as those from land clearing to establish
the Gnangara pine plantation or to build houses in the expanding metropolitan area of Perth.
Those actions have resulted in the total destruction of large areas of native vegetation.
Sustainability is regarded as an important criterion in judging whether a groundwater development should proceed. The measure of sustainability is the rate of abstraction versus the rate
of recharge into the aquifer through percolation from rainfall. Ideally the rate of abstraction
should not exceed the recharge. However, in some circumstances, where the groundwater
resources are sufficiently large, it may be desirable to ‘mine’ the groundwater, while knowing
that such mining would be unsustainable in the long term.
Returning to the example of the Gnangara project, it is providing a very large share of
Perth’s needs, but the aquifers have been produced at rates that exceed recharge, so that the
water table has fallen. In other words the rate of abstraction is above the sustainable level, but
this has been considered acceptable because the series of dry years in the Perth area has greatly
reduced water flow into dams. Without the increased production from Gnangara, Perth would
have had much more severe water restrictions. Consequently, production above the long-term
sustainable level has been deemed necessary and has not resulted in long-term deleterious
effects on the aquifers. The key point is that overproduction from an aquifer can be allowed as
a short-term solution to immediate water problems, but it cannot be continued indefinitely
without totally consuming the resource.
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Conclusions and recommendations
Conclusions
The main conclusions on water supplies in Western Australia, resulting from the symposium and subsequent discussions among members of the panel, may be summarized as follows:
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Western Australia is currently experiencing a time of climate uncertainty and there
is no consensus view among scientists as to whether the recent drying trend will
continue or be reversed.
Ambient surface temperatures have risen around the world, and some scientists link
this rise to emissions of ‘greenhouse’ gases, especially CO2 and methane, through
human activities.
Global climate is always changing; large fluctuations have occurred during past centuries and millennia, and some scientists believe that the present climate change
could be unrelated or largely unrelated to human-induced ‘greenhouse’ emissions.
Over the past 30 years Perth and most of the South West have experienced a 10%
reduction in rainfall, resulting in greatly reduced runoff into dams in the Darling
Range.
Some scientists have used computer modelling to suggest that this area will continue to experience low rainfall in the years ahead, but other scientists do not agree,
doubting the validity of the computer models.
Plans announced by the State Government for the injection of appropriately treated
waste water into shallow aquifers is welcome and will help to prevent depletion of
those aquifers
Because of the reduced runoff into dams Perth has become increasingly dependent
on groundwater, which now provides about 60% of domestic water needs and 80%
of total needs in Perth and adjoining areas.
Water demand in Perth and adjoining areas is expected to double in less than 50
years.
The potential for expanding low-cost potable water supplies for Perth is better than
for any other mainland capital city in Australia, because Perth has access to very
large resources of groundwater in the Perth Basin, whereas the other cities are
wholly dependent on surface water.
Most fresh-water rivers and streams in the Darling Range have now been dammed,
and Perth and the South West can no longer look towards dams for major increases
in water supplies, even if rainfall returns to average levels.
From 1962 to 1995 the Geological Survey of Western Australia carried out a program of strategic exploratory drilling in the Perth Basin between Geraldton and
Augusta, consisting of more than 200 bores, 500 to 1600 m deep, in 16 lines across
the basin, and these showed that the basin contains very large resources of fresh
groundwater, especially in the Jurassic Yarragadee Formation.
No strategic groundwater exploration by Government has occurred since responsibility for such exploration was passed from the Geological Survey to the Water and
Rivers Commission in 1996, then to the Department of Environment in 2001, and
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to the Department of Water in 2005.
It is vitally important to the State that the most recent change in the allocation of
Government responsibilities for water proves to be successful, given that our future
depends so much on wise planning for the discovery, supply, and efficient use of
water.
From 2003 to 2005 the Water Corporation funded a program, first proposed by the
Geological Survey in 1994, of evaluation drilling and hydrogeological analysis of the
South West Yarragadee Formation and associated strata.
It was announced in 2005 that the South West Yarragadee and associated aquifers
could sustainably produce high-quality water at up to 300 GL per year and that
production was expected to begin at a rate of 45 GL per year.
A decision was announced in 2004 for the construction of a sea-water desalination
plant at Kwinana, to supply 45 GL/year of water to the integrated water-supply
system.
It is likely that if evaluation drilling in the South West Yarragadee aquifer had been
conducted two or more years earlier, the decision to construct this high-cost and
energy-intensive desalination plant could have been deferred, as the Yarragadee
groundwater can be produced at a lower cost.
Recommendations
The following recommendations are made in relation to the above conclusions:
1.
2.
3.
4.
5.
6.
7.
The uncertainties inherent in rainfall predictions need to be taken into account
when formulating price, demand, and supply policies and making decisions for future water supplies.
The worst-case climate scenario for the South West is that of continued decline in
rainfall, and it is appropriate to address this possibility by expanding and diversifying sources of supply, re-using treated waste water, and promoting water conservation without unduly compromising current living standards.
It is essential to maintain long-term planning to meet the water-supply needs of
Perth and adjoining areas in anticipation of a doubling in demand in less than 50
years.
Similar forward planning is also required for other regional centres in Western Australia.
The Department of Water needs to reactivate strategic groundwater exploration,
which will require the hydrogeology section to fully re-establish its former roles in:
· groundwater exploration and resources assessment
· hydrogeological mapping
· maintenance of the groundwater database
· publication of groundwater reports
High priority should be given by the Department of Water to the preparation and
publication of a report to integrate the results of exploratory drilling in the Perth
Basin.
Another report is needed on shallow aquifers that have been developed by commercial and home bores in the Perth area.
12
8.
Prompt action should be taken by the Water Corporation to develop the known
water resources in the South West Yarragadee aquifer, for use in Perth and adjoining
areas of the South West.
9. Strategic drilling in the North Yarragadee aquifer should be undertaken as soon as
possible, with the objective of proving possible future water supplies for Perth and
the South West.
10. Consideration should be given to ‘mothballing’ the Kwinana desalination plant when
adequate supplies of less expensive water become available.
11. There is a need to adequately balance relevant economic, environmental, and social
aspects (the ‘triple bottom line’) when considering whether a proposed water-supply development project should proceed.
12. Sustainability is an important criterion in judging the viability of a proposed groundwater development, although in certain cases it may be expedient to allow some
mining of a groundwater resource.
13
APPENDICES
PAPERS PRESENTED AT THE SYMPOSIUM
THE PAST, PRESENT AND FUTURE
FOR WATER MANAGEMENT IN (SW)WA
Brian Sadler
Water Policy Services and
Indian Ocean Climate Initiative Panel
[email protected]
brian.sadler@big
pond.com
The earth, over geological time, has seen many changes in climate. Even in the 400,000
years or so, since hominids first appeared on earth, there have been several glacial and interglacial periods. However, over the last 10-15 thousand years since settled agriculture began and
human civilisation developed, the earth has been in the relative stability and comfort of an
inter-glacial period.
Geological time-scales are of little relevance, however, for contemporary planning. Most
commonly, practical planning decisions are made with outlooks at generational time-scales.
For such time-scales it has been universal practice to consider climate as stable. In other words,
the statistical variability observed in past climate records is assumed to be a good representation of future variability and risk (i.e. a stationary time-series).
Water supply development, planning, and water resources management have relatively long
lead-times and time horizons. Risks associated with variability in the hydrology of water systems and their ability to sustain supplies and allocations are a basic and critical issue. The
common assumption of stable climate has been the practical starting point for such determinations.
Global warming, regional climate shifts, and perhaps multi-decadal variability have rendered this assumption of climatic stability inadequate for the South West since the early 1970s.
However it took decades for the inadequacy to become evident. Change can only be identified
statistically when it has been established long enough to show above the noise of natural
variability.
To some extent the rainfall changes were anticipated by water managers at the time of the
Greenhouse ‘87 Conference (Sadler et al., 1988). However, only in the past decade has the
abruptness and severity of the change been identified conclusively (IOCIP, 2002, 2005). Even
now, the fundamental causes of the rainfall change cannot be defined with any certainty. However they are judged to be a combined outcome of anthropogenically driven change and multidecadal variability (IOCIP, 2002, 2005).
Challenges to present and future water management arising from climate observations and
science are:
1. Climate is not stationary - change will continue through this century altering environmental
14
2.
3.
4.
5.
6.
and water regimes
Regardless of cause, episodes as dry, or drier, than the past 30 years are now part of the
decision base line for the South West
Further (SW) drying is likely due to global warming but the resultant outcome will also be
affected by (less predictable) “natural” multi-decadal variability.
Climate is a resultant of chaotic systems. The expected drying “trend” may unfold with
steps, smooth trends, or even with temporary regressions
Uncertainty will continue with respect to real-time, as well as future, climate
Uncertainty will demand flexibility, robustness, new outlooks
The WA Government has fostered the notion of informed adaptation in which response is
empowered by the best available information. The simple assumption that the past represents
the future has failed and has no foresight. However, it is not easily replaced. Decisions must
now give attention to inference from gglobal climate models and understanding of the nature
of the implications of chaos.
Water planning in South Western Australia has been thrust into the national front-line of
such considerations. The scale of change (15-20% step rainfall decrease, 40-50% stream-flow
decrease) has drastically reduced the supply capacity of water systems and water allocations
established over the last century or more. The region has scraped through a crisis which may
well have been a critical test of vulnerability if imposed on less diverse water systems such as
Sydney and Melbourne. The scale of this challenge and achievement is little understood in the
wider community.
The history of past water management in WA and its legacy are important considerations
in looking forward to the future and to the issue of water management in climate uncertainty.
Western Australia has a rich water history coloured to no small degree by the specific nature of
its hydro-climate, its physical scale, low population density, economic development and public
outlook. The State has been both innovative and prepared to borrow vigorously from elsewhere, but with approaches adapted to the uniqueness of its circumstances.
In water resources management and water supply systems terms the State’s water history
may be described in six eras. Each of these eras leaves some legacy relevant to present and
future management. For this paper these eras are identified as follows
1. Pioneering Settlement Era 1829~1902
An era of piece-meal measures for settlement – severe sanitation problems. An era of self-supply, private
vendors and of low governmental profile. Perhaps the main legacy was a public expectation of greater State
responsibility
2. Public works Era 1902~1964
An era dominated by surface water schemes and works with Government legislation - Projects which built a
backbone for modern water systems. Pioneering attitudes continued. Salinity was identified, explained, largely
ignored.
15
3. Water Resources & Systems Era
- Modern age begins 1962~78
The era of development of hydrology, water resources measurement and computer data processing. An era of
exploiting water resources systems concepts - aided by computer simulation (stationary climate). An era for the
emergence of demand management, drought, concerted action on salinity
4. Consultation, EIS and Multi-objective Assessment Era 1975~86
An era of “new world” water resources influence with consultation environment and socio-technical issues to the
fore. Formal EIS procedures adopted ahead of compulsion. Public consultation at investigation front end
with triple bottom line outlook (multi objective planning processes). A vision of total water management and
pursuit of demand management
5. Strategic Planning & Sustainable Development Era - The Water Authority era 1985~95
An era of vigorous development and experimentation in strategic planning for balancing water supply/demand
and for water allocation
6. Water (market) Reform and Climate Change Era 1996 ~
An era when implementation of National Water Reform with its focus on markets, service delivery, structural
change coincided with recognition of the occurrence of a major climatic shift placing extreme pressure on
sustainable water management and greatly diminishing value of water supply sources
From this history the following legacies are suggested as particularly pertinent to management in climate uncertainty:
1. A robust, but climatically stressed, regional water system
2. A climate circumstance which shortened the planning horizon and spawned risk averse
responses
3. Future uncertainty with probable drying and a need for new decision rules
4. A tradition of water resources investigation, management and planning pertinent to the
circumstances
5. Some failures of national reform measures in support of strategic planning, resource assessment and monitoring
6. A substantial skill base with need for rebuilding in regulators
7. A substantial base of investigations and research with a run-down of State water resources
reconnaissance and assessment
8. A public debate more tactical than strategic
9. Reform, for which review of weaknesses as well as strengths may now be timely
Of particular significance, in this history, to water supply management in climate uncertainty has
been the development of water resource systems in which the whole is greater than the sum of
the parts. Since around 1973 principles of conjunctive use have been introduced and exploited
in the Integrated Water Supply System (IWS) of the South West and in the West Pilbara water
supply. In these systems, surface water sources provide bulk and groundwater provides security. The IWS is particularly sophisticated in its drought management capabilities with sources
currently ranging from run-of-river sources, large surface reservoirs, unconfined aquifers and
artesian sources. A component of desalination is planned and has potential to add further
16
robustness. It is important that future reform models or competition policy do not prejudice
the capacity to exploit these sources as a combined system with particular elements able to be
drawn upon or rested over periods of several years duration.
Future Challenges
The following challenges are seen to confront water policy and water management processes in the future century of climate uncertainty Achieving 1. Planning, approval and timely implementation of “total” water management responses to
uncertain climate
2. Policies, industry structure and regulatory capacity which sustain flexible water resources
systems capability
3. Governance to actively coordinate strategic planning of service providers and the State in
transparent public process
4. A stable Triple Bottom Line regulatory structure and decision context
5. Regulatory principles and allocation adapted to a non-stationary climate and to automatic
response of climate affected ecosystems
6. A strong information base on resources and climate
7. Leadership in mature, informed, inclusive and strategic public debate of issues
8. Community ownership of policies and appropriate community roles in adaptation.
WATER – THE NEXT GENERATION OF CHANGE
D J Blackmore
Water for a Healthy Country Advisory Council
[email protected]
The per capita availability of water has halved within the current generation. This is an
extraordinary reduction in access to a vital natural resource which will demand radical responses from both policy and technological solutions. Added to this is the long term climate
signal which in arid zones around the world indicates less rather than more water.
In Australia it is unlikely that large transfers of water from the north of Australia to the
south will be competitive with other approaches to water management. The future is to improve technologies and to continue to develop and implement policies which reflect the scarcity of water.
An important foundation issue is to understand how major urban systems operate and
where are the most likely points of intervention. CSIRO’s Water for a Healthy Country is
targeting this area and will contribute significantly to, not only our understanding of what is
possible, but also by developing solutions appropriate for the Australian landscape.
17
ISSUES ARISING FROM INTER-REGIONAL TRANSFERS
POLICY ISSUES AND APPROACHES
Harry Ventriss
Water Strategen
[email protected]
The State Water Strategy recognises that the transfer of water from one area of Western
Australia to another has been a part of the history of water supply in WA. In examining the
key issues that arise from notions of ‘inter-regional’ transfer, the key aspect that needs to be
addressed is competition between the water sectors for the available water rather than that
water is being taken to be used in another part of the State. Inter-regional transfer is not an
issue if there is adequate water for all needs and the “transfer” issue is a diversion from the
fundamental competition issue. The issue then becomes one of “how much water is available?”
This question becomes more difficult to answer with the uncertainty surrounding the prognosis for future climate in all parts of the State. This paper offers the basis for debate on a
policy response to dealing with the acceptability of impacts of taking water from a resource
given that the baseline against which acceptability might be judged is changing in an uncertain
way in response to climate change.
Given the difficulties and uncertainties in determining the future state (and even greater
uncertainties in determining the desirable future state) of water dependent ecosystems, the
response to climate change must:
·
be adaptive (avoid regulatory gridlock)
·
be based on monitoring and research
·
recognise that there is likely to be significant change to water dependent
ecosystems and associated values from climate change alone
·
manage the detected changes induced by the proposal within acceptable
parameters.
The specifics of what constitute “acceptable parameters” will be a matter of ongoing judgement as information becomes available over time. However, basic principles may be established to guide these future judgements.
Some of the key principles that are proposed to form the framework for future judgements
on changes induced by taking water resources include:
1. Ecosystems are dynamic and respond to climate change: Changes are most likely to
occur to water dependent ecosystems in the context of a drying climate. It should be
recognised that the ecosystems have shifted historically and preserving the current state of
these ecosystems may not be feasible or possible. It is difficult to predict the exact future
state of the ecosystem and the desirable future state.
18
2. Change is not necessarily damage: A key principle is the recognition and acceptance that
change does not inherently constitute a form of damage or is adverse. The characteristic
composition, structure, and processes of water dependent ecosystems may change, however, the extent to which such change can be considered to be adverse will largely depend on
the extent to which the full range of management principles are sustained. The rate of the
change may also determine the resulting composition and structure of the ecosystems.
3. Adequate levels of ecological productivity should be maintained over the region:
The change induced by a proposal should not be such that total ecological productivity
levels fall significantly below that induced by climate change over the region.
4. The resilience of the significant water dependent ecosystems should be maintained:
The change induced in these systems (eg conservation category wetlands and TECs) by the
proposal should not significantly affect the ability of these ecosystems to adapt to climate
changes and prevent reversal of these changes. The proposal should not lead to the loss of
any keystone species in these ecosystems in addition to those that may be lost through
climate change.
5. The conservation status of water dependent ecosystems types in the region should
not be raised: The proposal should not cause the regional conservation status of water
dependent ecosystem types or species within these ecosystem types (eg lakes, sumplands,
damplands/palusplain, woodlands, and heathlands) to be raised substantially above that
which would be induced by climate change alone. For instance, from vulnerable to endangered or susceptible to vulnerable.
6. No water dependent ecosystem or species should cease to exist: The proposal should
not result in loss of any water dependent ecosystem or species in addition to that induced by
climate change.
7. Any substantial loss in water dependent ecosystems should be offset: Any substantial
loss of water dependent ecosystems above that which would be induced by climate change
should be offset by rehabilitation or enhanced protection or management of other water
dependent ecosystems.
8. Monitoring and review to assess the extent of change and forecast future change is
an imperative: Adequate monitoring should be undertaken to assess change as it is occurring, and to provide for forecasting of future change as a means of identifying priority areas
for management effort.
9. Risk assessment of the consequences of the management options should provide
guidance to decision-making: This aspect of the Precautionary Principle will be an important part of decision-making on considering ‘acceptable change’.
These principles are preliminary proposals and the finalisation of the principles and development of an approach to their application would require extensive consultation with a range
of stakeholders.
Judgement of achievement of several of the principles will involve an understanding of the
changes that will be induced by climate change alone. This will require the identification of
appropriate control areas to enable this understanding to be developed. This will be an important aspect of any auditing of performance against achievement of the principles.
19
THE SOUTH WEST YARRAGADEE AQUIFER
Philip Commander
Department of Environment
[email protected]
The South West Yarragadee aquifer extends from Australind to the south coast and is
bounded in the east by the Darling Fault and in the west by the Busselton Fault. It is hydraulically separate from the Yarragadee aquifer in the northern Perth Basin, the Yarragadee Formation between Australind and Mandurah having been removed by erosion.
The formation extends to below the 1681 m total depth of GSWA Karridale 7 bore, and
contains fresh water , in places less than 200 mg/L TDS. Exploratory drilling by the Geological
Survey commenced at Busselton in 1966, but it was only with the drilling in the late 1980s of
the Cowaramup and Karridale Lines of exploratory bores that the full extent of the aquifer
beneath the Blackwood Plateau was known. The current investigation carried out by Water
Corporation fills in the gaps on the Blackwood Plateau between the GSWA drilling lines. The
investigation has employed aerial magnetic, ground electromagnetic and gravity surveys, with
drilling at some 68 sites, making it the largest groundwater investigation carried out in the state,
outside the Metropolitan area.
The Yarragadee aquifer contains a very large storage of some 400 cubic kilometres (based
on a porosity of 10%), and the estimate of 300 GL/a renewable groundwater resources for
the whole region made by GSWA in 1992 is close to the total net recharge to all aquifers in the
study area of about 375 GL/a determined by groundwater flow modelling.
The Blackwood Plateau is elevated along the Whicher Range in the north, and slopes southwards, being deeply dissected by the Blackwood River. The Yarragadee Formation in the Bunbury
Trough is overlain in turn by the Parmelia Formation, Bunbury Basalt and Leederville Formation, with superficial formations on the Swan and Scott Coastal Plains. The Leederville Formation, which covers the greater part of the plateau, also overlies the Sue Coal Measures and
Lesueur Sandstone in the Vasse Shelf to the west.
The Yarragadee aquifer crops out in a relatively small area on the south of the plateau, and
around the Blackwood River. Recharge occurs from rainfall in this area, and groundwater flows
north to Bunbury, where carbon 14 dates are around 30 000 years, and also towards the south
coast. Most of the plateau is covered by Leederville Formation, which is subdivided into three
members, the Vasse, Mowen and Quindalup. The Vasse is in hydraulic connection with the
Yarragadee in places, but much of the plateau is underlain by the more shaly Mowen Member,
which contains perched water bodies, unconnected with the Yarragadee aquifer.
Discharge from the Yarragadee and Vasse aquifers also supports fresh summer baseflow
and pools in the Blackwood River, which is saline during the winter. Utilisation of the groundwater resource in the Yarragadee aquifer will have to account for these groundwater dependent
environments along the Blackwood River, and also on the Scott Coastal Plain.
20
MANAGED AQUIFER RECHARGE ON THE SWAN COASTAL PLAIN
Simon Toze
CSIRO Land and Water
[email protected]
Water reuse was identified in the State Water Strategy as an integral part of water conservation for WA. A key initiative of the strategy is 20% reuse of treated wastewater by 2012.
Among the strategic objectives are to achieve significant advances in water reuse and encourage
‘fit for purpose’ water consumption through the substitution of potable supplies with reclaimed water. A major initiative identified to help reach and potentially pass this 20% target is
the recharge of reused water to aquifers (Managed Aquifer Recharge), particularly those beneath the Swan Coastal Plain.
The aim of this project is to address a range of knowledge gaps relating to Managed
Aquifer Recharge (MAR) with consideration of different types of source water (e.g. treated
drainage, storm and waste water). Currently, government regulators (e.g. DoE and DoH) are
having difficulty developing appropriate policy and guidelines relating to MAR due to existing
knowledge gaps and uncertainties, impacted by the fast pace of technological and scientific
advances. Further implementation of successful MAR schemes across the State will require
research to inform on a range of interlinked issues that will be addressed in this project.
Components of the planned research will focus on
· water quality improvements during recharge of recycled water to groundwater (eg
removal of pathogens and chemicals of concern via biogeochemical processes);
· existing and novel treatment technologies (including using the aquifer to improve
water quality);
· characterisation of aquifers identified as potential MAR sites to determine factors
influencing recharge and recovery efficiencies;
· management and operational requirements;
· assessment and management of risk (both human and environmental health); and
· the hurdles to social acceptance of water reuse projects.
There are many viable opportunities that exist for water recycling in the Perth Region via
MAR, given several major aquifer systems with favourable aquifer characteristics which impact
the efficacy of recharge. The project outcomes will enable government regulators to develop
more rigorous guidelines and will advance water recycling as a reliable alternative for safe new
supplies of water.
In addition, and just as importantly, the general public needs to be on side relating to water
reuse and Managed Aquifer Recharge, particularly when the reuse of the water approaches use
within residential households and for indirect potable. A number of schemes worldwide have
failed due to public opposition because the public were not involved from the beginning of the
reuse schemes and had little or no trust in the water reuse process or the operators responsible
for the scheme. This project is a vital opportunity to engage the public during a pilot scale,
experimentally based MAR project and, hopefully, develop their trust that MAR can be used
safely, efficiently and in a sustainable manner on the Swan Coastal Plain.
21
COMMUNITY ATTITUDES TOWARD WATER USE AND WATER PRICING
Geoff Syme
CSIRO Land and Water
[email protected]
Water use is largely inelastic given current levels of pricing. Elasticity is extremely low
internally because this is largely driven by habitual behaviour. Efficiency means or in other
words water saving appliances are the best way to go internally to save water. External use is
about seven times more elastic than internal use and has a number of curtailment (behavioural
change) as well as efficiency (technology) options for saving. It is about 8 times more elastic
than internal use. This level is still only about 0.3 which is regarded as low. For price to be
effective it needs to be considered in conjunction with a loose social contract which takes
account of the social impacts of tariff change, community service obligations, the ethics of
water allocation and governance aspects. Before addressing these social issues it is suggested
that pricing will not be as effective as it could be in promoting conservation until water use is
regarded in a consumer behaviour paradigm. Essentially people need much quicker feedback
on what they are consuming and on what they are using the water for before the connection
will be made between household water bills and their water consumption. For the social issues
examples of how to assess social impact of pricing and other policies given knowledge of the
predictive effect of lifestyle on water consumption are given. In addition the issues of community service obligations and the benefits water access gives lower income residents are considered. Finally, the structure of ethical assessments of water allocation decisions and the role of
trust in acceptable levels of service and governance were discussed.
WATER POLICY CHALLENGES IN AN ENVIRONMENT OF UNCERTAINTY
Aynsley Kellow
School of Government, University of Tasmania and
Policy Program, Antarctic Climate and Ecosystems CRC
[email protected]
The challenge for Western Australia is not one of developing water policy in a drying climate, but one of adapting to climate uncertainty. It would be as gross an error to make decisions
on the assumption that current climate will persist or become drier, because it is widely acknowledged that no reliable regional climate models are available. The very change to drier
conditions in the South-west of Western Australia underscores this point: the shift to a drier
period occurred abruptly at around 1976-77, and, nobody seems certain as to the cause of the
shift. More and more observational data will doubtless improve our understanding of the
phenomenon, but the non-linear nature of the system will continue to confound our best
attempts at prediction. What is needed for water policy under conditions of uncertainty are
approaches such as those developed in the electricity sector, such as Least-Cost Utility Planning, which examine the costs of various alternative approaches under a range of scenarios,
possibly weighted for probabilities. Such an approach will favour responses with lower fixed
costs and proportionately higher variable costs, and might mean that options like desalination
plants make a contribution to water policy even if they lie idle. This requires leadership and
public education regarding the real nature of the problem, lest political pressures lead to the
capacity of such plant being used to supplement supply, rather than to hedge against uncertainty.
22
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2005
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for the facts and opinions advanced in any of its publications
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