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Books Online
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Volume 2011
Number 2 2011
Water - Science and Solutions for Australia
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| Foreword
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Megan Clark, CSIRO Chief Executive and Andrew Johnson, Group Executive – Environment, CSIRO
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CSIRO is committed to providing scientific advice on the major challenges and opportunities that face Australia. We commend to you this summary of the latest scientific knowledge on the challenges and prospects for managing water resources in Australia.
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| Introduction
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Bill Young and Ian Prosser
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In order to secure water for future generations, Australian governments, industries, and
communities will want to understand current and future water availability and explore ways of
meeting the demands on these water supplies. They will want to better understand how river
systems and groundwater systems respond to a changing climate and to increasing water use, and
they will want to be confident that water use will not unduly harm future water supplies through
pollution, over-use or environmental degradation. Improvements in ecological understanding, and
in understanding the human health and other implications of contaminants in water, can provide
vital help in developing water plans and provide safe and reliable water for all uses, including
environmental water.
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| Current water availability and use
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Ian Prosser
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Overall, Australia has sufficient water resources to support its current uses, consuming 6% of renewable water resources each year.
Current use of rainfall and water resources in effect meet the needs of more than 60 million people, through Australia’s exports of agricultural produce.
A very uneven distribution of water resources across Australia and high year-to-year variability means that water resources in some regions are fully or over allocated, while others remain largely undeveloped.
Australia’s arid landscape and high potential evaporation pose challenges from the high demand for water by crops and cities, and large water losses from reservoirs and inland rivers.
Some water resources are at risk from bushfires and unlicensed uses, which can reduce water availability to licensed users.
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| Water values
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Rosalind Bark, Darla Hatton MacDonald, Jeff Connor, Neville Crossman and Sue Jackson
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As a society, Australians value water highly for a range of economic, environmental, social, and cultural benefits, which at times are in conflict with each other.
Water resources are an input into the production of most goods, and water environments support economic uses such as fisheries, tourism, and recreation.
Healthy water environments provide valuable ecosystem services such as maintenance of water quality and habitat, and many people intrinsically value and feel highly attached to water-related environments.
For Indigenous Australians, water is central to culture and identity, as well as livelihood, but these values are poorly understood.
Increasingly market mechanisms, such as water trading, are used to resolve competing uses, but regulation, community aspirations, and valuation of ecosystem services are also important future drivers.
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| Water and climate
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Francis Chiew and Ian Prosser
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Floods, droughts, and climate change are the three most important influences of climate on Australia’s water resources.
Water resources are vulnerable to both climate variability and change; for example, runoff into Perth’s reservoirs has declined by 55% since the 1970s and the 1997 to 2009 drought resulted in unprecedented decline in runoff and water use in the southern Murray–Darling Basin.
Climate change has played a part in recent reductions in rainfall and water resources, however its specific contribution is difficult to quantify.
Climate change by 2030 is likely to reduce average river flows by 10% to 25% in some regions of southern Australia but further climate change could produce even more profound reductions of water resources in southern Australia.
The relationships between climate and runoff are now being used to provide more accurate seasonal forecasts of water resources useful for irrigators, dam operators, and environmental managers.
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| Groundwater
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Andrew Herczeg
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Groundwater use is increasing and it is the main source of water for much of Australia’s dry interior.
Groundwater shares many of the same sustainability issues as surface water, with the added complication that over-use may not be detected for several decades because of slow renewal and movement of the resource.
Groundwater resources are strongly connected to surface water supplies, and many of Australia’s ecosystems, plants, and animals depend upon groundwater for their survival.
The sustainable extraction limit of an aquifer is usually much less than the rate of annual recharge, or renewal. Pumping aquifers causes groundwater levels to fall, affecting ecosystems and river discharge, and increasing salinity.
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| Water quality
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Simon Apte and Graeme Batley
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Strict water quality controls are in place to protect human health and aquatic ecosystems from chemical, and biological pollutants.
In general, control of pollutants at their source is more effective than remediation because of their persistence in the environment and concentration through the food chain.
Elevated levels of salinity, nutrients, metals, pathogens, and organic contaminants (e.g. pesticides) are the main causes of poor water quality in Australia. Pollutants are derived from a wide range of sources including agriculture, industry, and urban areas.
Sediment layers at the bottom of waterways are a major sink for nutrients and contaminants, which can be released into waters and become toxic under certain conditions.
New contaminants, for example pharmaceuticals, are continually emerging and much monitoring and research is focussed on detecting their presence and toxicity in aquatic environments.
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| Urban water sustainability
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Alan Gregory and Murray Hall
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An extra 10 to 20 million people could be living in Australian cities by 2050, requiring more water supplies, more wastewater disposal, and greater energy use to provide these services.
The increasing demands for water, energy, and other resources in cities are leading to new approaches to urban water as part of broader urban sustainability and liveability.
There is considerable potential to improve urban sustainability by recovering water, energy, carbon, and nutrients from wastewater and reusing them in the city and as fertiliser for food production.
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| Future urban water supplies
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Stewart Burn
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Australia’s largest cities are forecast to require 1150 GL/year (or 73%) above the current supply of 1505 GL/year by 2050. In addition, current supplies will probably reduce as a result of climate change, requiring additional augmentation.
Desalination is the most adopted technology to date, providing 484 to 674 GL/year of additional water. There is potential for major improvements in the efficiency and cost of desalination.
Other potential water sources include rainwater tanks, capturing and reusing stormwater, and indirect potable recycling – all of which have their particular strengths and weaknesses.
Traditionally, financial and technical considerations were emphasised when exploring new water supply options; now, consideration is also being given to social acceptability, and environmental costs and benefits. There will be different solutions to new supplies for each city, given their very different situations.
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| Irrigation
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Mac Kirby
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Irrigated agriculture is productive and profitable, generating 50% of all agricultural profit from just 0.5% of agricultural land.
Australia exports 60% of its agricultural produce and demand should grow with increased standards of living and growing global populations.
Two-thirds of irrigation in Australia occurs in the Murray–Darling Basin where it faces major challenges from climate change, return of water to the environment, and an increasingly open water market.
New irrigation development is occurring in Tasmania and there are prospects for new developments in northern Australia, and along the east coast.
Increasing demand for irrigated agriculture and declining water availability will drive increases in the efficiency of irrigated agriculture.
Efficiency can be improved through more water-efficient crop varieties, improved farm management, precision applications of water, and more efficient irrigation supply canals, and river management.
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| Water for the environment
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Rod Oliver and Ian Webster
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Aquatic and water-dependent ecosystems require surface water flows or access to ground water to survive. They include Australia’s highly valued rivers, lakes, floodplains, wetlands, and estuaries.
Regulation of rivers with dams and weirs and the extraction of water from rivers and groundwater threatens the viability of these ecosystems, many of which are now degraded.
To function properly, these ecosystems and the species in them require not just adequate volumes of water but the right seasonal pattern and variety of conditions.
Providing water for consumption while providing for ecosystems often involves trade-offs or compromises. A good understanding of the condition of ecosystems under different regimes of water use, can help make these trade-offs transparent and identify ways to reduce them.
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| Water in mining and industry
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Ian Prosser, Leif Wolf and Anna Littleboy
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Mining, manufacturing, and other industries use about 20% of all water consumed in Australia. They use water in cities and in some fully or over-allocated rural systems, placing them under the same pressures as other users to use water more efficiently.
Water efficiency improvements have been made by adopting new technologies, more efficient processes, incorporating reuse, and recycling and finding alternative sources of water.
Mining is a large industrial water use that is growing fast, and uses water in remote areas where it often ‘self-supplies’. It discharges large quantities of water to the environment, requiring risks to water quality to be managed.
Coal seam gas is an industry set to expand on a massive scale in Queensland and northern New South Wales. It poses several water management challenges, including potential impacts on surrounding aquifers and their water users, and the safe treatment, disposal, or use of the saline water that is extracted.
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| Conclusions
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Ian Prosser
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There is a high level of expectation of benefits from water resources across a wide spectrum of economic, social, and environmental values.
Australia has sufficient water resources to meet its needs, but the locus of use around the major cities and in the Murray–Darling Basin creates problems of regional over-use and the need to find alternative water supplies.
Demands on water resources are growing – from increased urban populations, increased prospects for irrigated agriculture, and the booming minerals and gas sectors – while, at the same time, society recognises the need to provide water for the environment.
Climate change poses an additional pressure on water resources but Australia’s adaptability to droughts and floods will help the management of further adaptation to climate change for a few decades at least.
Australia is in a strong position to face its water challenges: having safe and reliable supplies of water, having achieved significant water reforms, and having solid institutions and many opportunities for innovation.
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These articles have been peer reviewed and accepted for publication. They are still in production and have not been edited, so may differ from the final published form.
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