Water in AustraliaFacts & Figures, Myths & Ideas

Blind Freddy can see that the answer to water shortages is to build more dams. Truth is, water problems can be very subtle, so it’s worth understanding more about

them before believing in particular solutions. This book aims to help the reader understand some of the ifs

and buts about water. It’s meant to be user-friendly for ordinary people to understand water a little better;

perhaps to be the informed voice in a discussion over the barbie, or to follow arguments being

put in the media.

WA

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Water in Australia Facts & Figures, Myths & Ideas

3

Australian Water AssociationSydney

© Australian Water Association 2007First published 2007

This book is copyright. Apart from any fair dealing for the purposes of private study, research, criticism or review as permitted under the Copyright Act, no part may be reproduced, stored in a retrieval device, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior written permission. Enquiries to be made to the Australian Water Association.

Copying for educational purposesWhere copies of part or the whole of the book are made under Part VB of the Copyright Act, the law requires that prescribed procedures be followed. For information, contact the Copyright Agency Limited.

National Library of AustraliaCataloguing-in-Publication data:Australian Water Association

Water in Australia: Facts & Figures, Myths & Ideas

1. Water supply

978-1-921335-00-6

Edited by Chris DavisDesign and layout by Andrea SmithIllustrations by Matt DavisPrinted by Digital Print AustraliaPublished by the Australian Water Association

Intr

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On top of Australia’s very variable rainfall and regular droughts, it’s now challenged by climate change. There are difficult decisions to be made about water, and people are very interested in how water should be managed. Many aspects of water seem quite simple and, as the old Australian phrase goes, Blind Freddy can see that the answer to water shortages is to build more dams (to quote just one example). Truth is, water problems can be very subtle, so it’s worth understanding more about them before believing in particular solutions.

This book aims to help the reader understand some of the ifs and buts about water. It is not a scientific text, nor a training manual. It’s meant to be user-friendly for ordinary people to understand water a little better; perhaps to be the informed voice in a discussion over the barbie, or to follow arguments being put in the media. The first section includes some basic facts and figures about water in Australia; then there is a series of myths and ideas, followed by explanations. Some ‘myths’ are obvious, but others are harder to categorise.

There are many other sources of information and a few of those have been offered here, often with Internet addresses. No academic citations are used to acknowledge sources, but most items have a ‘more information’ bit at the end. The most widely used reference is the Farmhand Foundation’s book Talking Water; which contains a wealth of useful information.

As one of Australia’s challenges is finding enough water, this book is devoted entirely to ideas about water quantity, not quality. That is not to suggest that quality is unimportant. On the contrary, it’s critical, but we’ll discuss it in a subsequent publication.

Chris Davis

CEO

Australian Water Association

4 5

Co

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Riv

ers Rivers played an important role in shaping the Australian

landscape, not to mention its culture. Fed by groundwater sources and surface runoff, some Australian rivers flow continuously and others only intermittently. In dry areas intermittently flowing streams are common; where water may be lost from the river to the groundwater below the channel.

The Murray-Darling is Australia’s longest river system, draining parts of Qld, NSW, Vic, and SA, reaching the sea on the SA coast. The Murray is 2 520 km long, while the longest branch of the combined Murray-Darling system, with its headwaters in Qld, is 3 370 km long.

Western Qld has a number of inland-flowing rivers such as Diamantina and Cooper Creek. Some drain into inland salt lakes that are dry most of the time (such as Lake Eyre in SA) or they disappear on the plains of the Central Lowlands without reaching any other river system.

Several long rivers in the tropical north experience huge variations in flow between seasons. The Mitchell in northern Qld has discharges in the wet season about 100 times those in the dry. The Gregory and Leichhardt in northern Qld, the Daly in the NT, and the Ord and Gascoyne in WA all flow intermittently.

Australian river discharges are tiny compared with those of many rivers elsewhere. For example, the annual discharge from the Amazon basin in South America is about 7 000 cubic kilometres, while the Mitchell, Australia’s largest river, discharges just 12 cubic kilometres per year.

More information Australian Bureau of Statistics Year Book 2006 http://www.abs.gov.au National Land & Water Resources Audit 2002 Australian Catchment River and Estuary Assessment http://audit.ea.gov.au/ANRA

Introduction 3Table of contents 4 Facts & Figures Rivers 5Groundwater 6Dams and storing water 7How much water does Australia have? 8How much do we use? 9Paying for water 10 What water earns 11Who does the water belong to? 12 The National Water Initiative 13 Water trading 14 Units of measurement 15Ideas & Myths Industry uses most of our water 16A rainwater tank for every home 18 Stormwater collection for use in our cities 20 Recycle water instead of letting it go to waste in outfalls 22Twice around – reusing water 24 Desalination uses too much energy 26Build more dams 28 Build dams near the coast where it rains more 30Prevent evaporation from reservoirs 32Dig out reservoirs to increase storage 34We can always count on groundwater 36A national water grid 38Turning rivers back inland 40 We need drip irrigation for all crops 42Farm in the north where the water is 44Water supply from the north 46Shipping water in tankers 48Moving water long-distances by canal 50Towing icebergs from Antarctica 52Drain seawater from Spencer Gulf into Lake Eyre 54Cloud seeding can supplement our water resources significantly 56The price of water is wrong; it’s too cheap (or too expensive) 58Water words 60Other information sources Web links 62Organisations and Reference books 64

6 7

Groundwater is that water stored underground in rock fractures and pores.

Groundwater systems may overlay and interact with each other and reflect the various geological settings of the Australian landscape. Australia has some 538 groundwater management units, without which, much of inland Australia could not have been developed.

Australia has 25 780 GL of groundwater that can be extracted sustainably each year and is suitable for potable, stock and domestic use, and irrigated agriculture. Approximately 4 100GL of groundwater is used annually, of which more than 10% is supplied by the Great Artesian Basin (GAB). The GAB is Australia’s largest source of groundwater, storing about 8 700 000 GL and extends across 1.7 million km2, occupying 22% of Australia’s land area, under parts of South Australia, New South Wales, Queensland and the Northern Territory. Water from the GAB supports extensive pastoral and mining industries.

About 30% of Australia’s 538 groundwater management areas are either close to or overused when compared with their estimated sustainable yield. In terms of licences for groundwater extraction, 168 groundwater management units are either fully allocated or over-allocated when compared with estimated sustainable yield

Ground water use in Australia’s States and Territories has increased in recent years. Up to four million people of Australia depend totally or partially on groundwater for domestic water supplies. The Northern Territory and Western Australia have the highest proportions of distributed water originating from groundwater sources, making up approximately one third of their total water supplies.

More informationDepartment of Agriculture, Fisheries and Forestry 2004 Australia – Our Natural Resources

Gro

und

wa

ter

Da

ms

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sto

ring

wa

ter A dam is a wall of earth, concrete or rock, built to control

surface water. It stores the water in times of excess flow and releases from the reservoir to meet the needs of water users. The location of any large dam depends on geography, nearby population and industries, and the availability of runoff. Various dams and weirs control many Australian rivers to provide water for irrigation, industry and domestic use.

There are 501 large dams in Australia; that is, dams with a wall height greater than 15 metres, or having a reservoir capacity of more than 1 000 ML and the ability to deal with a flood discharge of more than 2 000 kL per second. At 180m in height, Dartmouth Dam in north eastern Victoria is Australia’s highest dam. Lake Pedder, on the Gordon River in Tasmania, is the largest reservoir stored behind a dam, holding up to 12 450 GL.

The majority of Australia’s large dams were built between 1970 and 1990. The number of dams has not changed much in recent years, although new dams have been built, especially in Queensland and Western Australia. Australia’s large dams have a collective storage capacity of 83 853 GL (i.e. more than 4 000 kL per person). Large dams in New South Wales (24 629 GL) and Tasmania (23 652 GL) have the greatest storage capacity.

There are estimated to be more than 2 million farm dams across Australia, with a total storage capacity of about 8 000 GL, i.e. about 10% of that stored in large dams.

More informationAustralian National Committee on Large Dams Incorporated Register of Large Dams in Australia http://www.ancold.org.au Australian Bureau of Statistics 2006 Water Account 2004-05

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Australia, the driest inhabited continent, has a limited amount of fresh water. Rainfall is highly variable, with large areas of the interior having average annual rainfall less than 300 mm; and rainfall varies dramatically from year to year and from season to season.

While the average rainfall for the continent (469 mm/year) is not particularly low, only 12%, on average, runs off land to collect in rivers. For 2004–05, the ABS Water Account estimates that rainfall volume across Australia was 2 789 424 GL, of which only 9% became runoff (242 779 GL). Most rainfall is lost to evaporation and transpiration (used by plants) and only about 1% percolates into aquifers to become groundwater. Of the runoff that does happen, about 70% is from rivers in the north, far from population centres.

Australia’s total water stored was less than half the total storage capacity (over 83 000 GL in large dams) and the total water stored in June 2005 was 39 959 GL, down 10% from the previous year. Western Australia (83%) and the Northern Territory’s (70%) reservoirs had the highest storage levels while New South Wales (33%) and Victoria (39%) had the lowest. Australia also has more than two million farm dams, with a capacity of about 10% of the large dams.

Since 2001 there has been a significant reduction in water storage levels of reservoirs across Australia, which has led to water restrictions in most capital cities.

The total volume of groundwater stored across Australia is not known with any certainty, but the estimate of safe annual extractions was 25 780 GL/yr in 2000.

More information National Land and Water Resources Audit 2000 National Water Resource Assessment Commonwealth of Australia http://www.nlwra.gov.au Australian Bureau of Statistics 2006 Water Account 2004-2005 http://www.abs.gov.au

Ho

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? The latest Water Account figures from the Australian Bureau of Statistics show that in 2004–05, 18 767 GL of water was consumed within the Australian economy. That figure does not include water passing through hydroelectric schemes.

The agricultural industry was the main consumer of water in 2004-05 (12 191 GL, or 65% of total use), most being used for irrigation of crops and pastures. Households were the next biggest user, at 2 108 GL (11%). Manufacturing and other industries used a comparatively small volume of water (1 648 GL), as did the mining (413 GL) and forestry and fishing industries (51 GL).

Householders consumed 2 108 GL of water in the same period. For a population of 20.3 million, on average, that equates to 104 kL of water per person per year, or 285 L of water per day. Western Australia reported the highest consumption per capita (493 L/day), followed by the Northern Territory (419 L/day) then Tasmania (392 L/day). Victoria and New South Wales had the lowest per capita consumption (222 and 230 L/day, respectively), followed by South Australia and the Australian Capital Territory (both 255 L/day). ABS water consumption figures are compiled in a way that is different from other reports, so exact correspondence is not easy to demonstrate, mainly because the ABS lumps losses and other water supply system uses separately from other figures.

Although not reflected in the ABS figures, the urban water industry is generally believed to reuse about 11% of water supplied, mainly for irrigation.

More information Australian Bureau of Statistics 2006 Water Account 2004-05

10 11

Payi

ng fo

r wa

ter The average price of mains water in Australian cities and

towns is around $1 per kilolitre (i.e. $1 per tonne), which is low when compared with other developed countries and with other products. In fact, some customers pay much less than $1, depending on the location.

For 2005, the average Sydney household paid $330 each year for its annual water bill and $347 for sewerage – a total of $677. The average combined bill in Melbourne was $537 that year, while Perth families paid up to $722.

The full cost of water, whether delivered to urban users through a mains system or pumped directly from rivers or aquifers by irrigators, should take into account:

operating expenses - all the expenses that are part of normal day-to-day operations including wages and the electricity required for pumping; ongoing maintenance costs - all the expenses of planned and unplanned repairs and replacements of water infrastructure; cost of monitoring and research - due to the complexity of water-dependent ecosystems, the collection of baseline information and research programs are crucial; cost to the environment or third party impact - water use and water disposal often imposes costs on others downstream and impacts environmental flows to vital ecosystems.

Increasing water prices can be politically sensitive. Some people feel that because water is a basic human need it should be free. It is ironic that Australians are prepared to pay a thousand times more for bottled water than they do for tap water of much the same quality.

More information WSAAfacts 2005 Water Services Association of Australia http://www.wsaa.org.au Australian Parliament 2002 The Value of Water: Inquiry into Australia’s Management of Urban Water http://www.aph.gov.au www.urbanecology.org.au

Irrigation has been a feature of Australian agriculture since the first large scale irrigation schemes were set up in the 19th Century. Most of the water used in agriculture is for the irrigation of pastures and crops.

In 2003-04, 10 000 gigalitres of water was irrigated, supporting agricultural production on 40 400 farms over an area of 2.4 million hectares, mostly in the Murray Darling Basin. This represents only 0.5% of all the agricultural land in Australia, but accounted for about 70% of all the water consumed by rural, industrial and domestic users.

Irrigation supports a mix of agricultural activities:

pastures – grazing, seed production, hay and silage; broadacre crops – rice, cereals, sugar cane, cotton, soy beans, canola, cut flowers and turf; and horticulture – fruit, nuts, berries, vegetables and grapes. Irrigated produce was estimated to have earned around $9 billion in 2003-04 (about a quarter of the gross value of all agricultural output). About half of this came from irrigated horticulture, and a quarter from both irrigated pastures and broadacre crops.

Pastures used for the grazing of dairy cattle, mainly in Vic, NSW and SA, used the most irrigation water, but this has decreased in the past 20 years. On average, irrigators earned $220 415 per farm in 2003-4, according to the ABS survey. Irrigated pastures earned just $152 539 per farm, while cotton farms earned an average of $1 264 716 (note that cotton farms are often much larger than others). All these figures are for GVIP, or gross value of irrigated product; so they don’t account for other sources of income.

More information Australian Bureau of Statistics Characteristics of Australia’s Irrigated Farms 2000-01 to 2003-04 www.abs.gov.au

Wha

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Who

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? In Australia, water belongs to the Crown, which means the relevant minister in each state or territory. Urban consumers who pay for water supply, and irrigators who have licences are simply paying for the right to use the water. Water rights used to be attached to riparian land (property with a river frontage) but water rights are now separated from land and can be traded. There is a grey area around used water, especially when it’s been purified and discharged – does it belong to the water utility; to the people who’d paid for it; or to the state government? That question is being researched.

Who’s in charge of water? The Constitution puts water management in control of Australia’s state and territory governments. It is a complex process and there are many laws and agencies (as many as 800) that deal with the administration and management of water. Water supply and wastewater treatment systems are run as a public service by water utilities, owned by either local or state/territory governments.

The Council of Australian Governments (COAG) provides a forum for the states and territories to negotiate with the Australian government over matters of common concern, including water management. COAG agreed on major reforms in 1994 then re-affirmed the commitment with the National Water Initiative in 2004. Its aim is improving the security of water access entitlements, ensuring water is put to its best use through the sharing of water between states and the development of interstate water markets.

More information Conacher & Conacher 2000 Environmental Planning and Management in Australia. Oxford University Press. National Water Commission 2005 Australian Water Resources 2005 www.water.gov.au

While the states and territories own and manage water resources, the Australian Government provides national leadership and strategic direction on water matters. The Australian Government led the development of the National Water Initiative (NWI), which has now been signed by all the states and territories. The aim of the NWI is to improve the economic efficiency of Australia’s water management, while also protecting our resources and the environment. The objectives include policy settings that help to achieve improved water resource planning, better management of cross-border water issues and innovative approaches to urban water management.

The NWI will result in:

• expansion of permanent trade in water, bringing about more profitable use of water and more cost-effective and flexible recovery of water to achieve environmental outcomes

• more confidence for those investing in the water industry thanks to more secure water access entitlements, better and more compatible registry arrangements, better monitoring, reporting and accounting of water use, and improved public access to information

• more sophisticated, transparent and comprehensive water planning that deals with key issues such as the major interception of water, the interaction between surface and groundwater systems, and the provision of water to meet specific environmental results

• a commitment to addressing overallocated systems as quickly as possible, in consultation with affected stakeholders, addressing significant adjustment issues where appropriate, and better and more efficient management of water in urban environments, for example through the increased use of recycled water and stormwater.

More information http://www.nwc.gov.au/nwi/index.cfm

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In many parts of Australia, rural water use is managed through the granting of water access entitlements and water allocations. A water access entitlement, such as a water licence, refers to an ongoing entitlement to exclusively access a share of water. A water allocation refers to the specific volume of water that is allocated to water access entitlements in a given season.

Water trading is the process of buying, selling, leasing or otherwise exchanging water access entitlements (permanent trade) or water allocations (temporary trade). Essentially, it involves buying water from one area and moving it to another. Australian water markets are still developing and have, so far, been dominated by temporary transfers, partly owing to the lack of secure water entitlements.

The creation of an open and effective water trading market is critical to achieving a sustainable balance in water resource management. The major benefit of water trading schemes, when well designed and implemented, is that they can provide an efficient and cost-effective way of reallocating limited water resources to ensure water is put to its highest value use.

The result of water trading is more effective production from the same volume of water. In addition, it also brings environmental benefits where water is traded from degraded areas and/or low value low efficiency production to areas more suited to irrigation, where improved management practices are used on higher value crops.

A properly functioning market for water entitlements allows each farmer to decide whether to use, sell or buy water at the market price. The price of water fluctuates according to supply and demand conditions, just like that of other commodities. For 2004-2005, water traded amounted to 1 300 GL, out of a total irrigation consumption of 12 191 GL.

More information Australian Bureau of Statistics Water Access Entitlements, Allocations and Trading 2004-05 www.abs.gov.au

Wa

ter t

rad

ing Units of measurement for water

Symbol Definition Name Practical example

Length

m standard unit metre one large pace

mm 1/1,000 m millimetrecardboard thickness

km 1,000 m kilometre 5 minute fast jog

Volume

m3 standard unit cubic metre5 44-gallon oil

drums

kL same as m3 kilolitre box trailer

L 1/1000 m3 litre carton of milk

mL 1/1,000 L millilitre 5 mL = 1 teaspoon

ML 1,000 m3 Megalitre half Olympic pool

GL 1,000,000 m3 Gigalitre Australia uses 21,000 GL/y

km3 1,000 GL cubic kilometreWorld’s fresh water

10,530 km3

Mass

kg standard unit kilogram loaf of bread

t 1,000 kg tonne load for large ute

Flow

L/s 1/1,000 m3/s litre per secondgarden tap max.

0.3 L/s

cumec 1 m3/scubic m per

secondmodest river

ML/d 1,000,000 L/d megalitre per day3,000 people use 1

ML/d

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Ide

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Although some industries (especially food, beverages and paper) do use a lot of water, it is actually much less, in total, than used by households and a lot less than irrigated agriculture uses. Australia’s total water consumption, per person, amounts to about 3000 litres (3 kilolitres) per day. Of that, two thirds is used for irrigation; the next biggest user is households, which take up 11.1%. Industry comes way behind that, taking up just 3.1% of the water for manufacturing and 5.6% for other industries.

From the 1980s, most water authorities and local councils began charging wastewater discharge tariffs on industries; usually based on a combination of the volume discharged, and the contamination load. This persuaded factories to use less water; the result is that many Australian businesses are now world leaders in water efficiency. For example, Yatala Brewery in Queensland uses about 2.2 litres of water per litre of beer brewed, compared to a typical world figure of more than three litres per litre. Twenty years ago, a brewery could use between five and eight litres per litre of beer.

The improvements mean industrial use overall is not a major fraction of total consumption. With water shortage a serious problem in many Australian towns, even minor water users need to be as efficient as possible. More attention is being paid to water efficiency generally. Water audits are carried out (consumption is measured carefully, throughout the factory/building), to find out exactly how much water is used, where and why. This often shows up previously unknown leaks, as well as hot-spots of high usage. Generally, quite simple actions can reduce water consumption significantly.

More informationhttp://www.sydneywater.com.au/SavingWater/InYourBusiness/Manufacturers.cfmABS WaterAccount, Australia 2004-2005 http://www.abs.gov.au/Ausstats/abs@.nsf/0/34D00D44C3DFB51CCA2568A900143BDE?Open

According to this myth, industries guzzle water, depriving communities and wasting resources. It’s quite widely believed and its origins are not easy to pinpoint, unless it’s a legacy of thirty years ago, when some wet industries were, indeed, big users of water.

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Ide

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Rainwater tanks have always been important to supply drinking water in rural and remote parts of Australia. In urban areas, rainwater tanks can provide an additional supply of water. Capture of rainwater also reduces the flows of stormwater into street gutters and local streams.

While rainwater tanks can make individual homes more self-sufficient, there are several reasons why a blanket rule for installing rainwater tanks in all homes is not appropriate for every suburb:

• In many urban areas there is a lack of space, particularly in areas of urban consolidation where medium to high-density living is on the increase.

• Rainwater tanks can be costly to install – a small tank will cost a minimum of $500 and a large one up to about $8 000. Although some water businesses offer rebates for tanks, the householder shoulders most of the cost, with little prospect of a quick payback from savings.

• In low rainfall areas, such as Central Australia, a house with a roof area of 255m2 would not collect enough rainwater to sustain the household, but it could supplement another source, such as groundwater.

• The water from domestic rainwater tanks is usually not treated or managed as well as the major urban water supplies; it can be contaminated by animal and bird droppings on the roof. In urban areas, there is the potential for contamination from airborne pollution. Collected rainwater quality is dependent on householders carrying out a maintenance program, which should include frequent cleaning of the roof and gutters, and regular sludge removal from the tank. Filtration and disinfection is desirable if the water is used for drinking and cooking.

More informationNational Public Health Partnership 2004 Guidance on Use of Rainwater Tankshttp://enhealth.nphp.gov.au/council/pubs/pdf/rainwater_tanks.pdf

It has been suggested that rainwater tanks should be installed in all new and redeveloped homes, to reduce the demands on reticulated water supplies, delaying the need for new water supply infrastructure and reducing the need for spending on stormwater infrastructure. Obviously, tanks do have the ability to catch rainwater for local use, so it seems a good proposition.

20 21

Ide

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There is no doubt that water collected and used locally is a valuable resource and that it should be done wherever practical. What makes the situation more complex are questions of scale, quality and practicality. Rainwater tanks for homes are relatively expensive. It is more economical to collect water from large roof areas, like shopping centres, factories and sports stadiums, since a single, large tank is more economical than several small ones.

Apart from roof runoff, urban stormwater comes mainly from roads and is generally a difficult water source: it happens very suddenly and erratically and comes in very variable quantities, from a trickle to a massive flood. Collecting, storing and purifying it is a serious challenge: finding places to build reservoirs (which would be empty most of the time); pumping the water around fast enough; and building water treatment plants which could swing into action instantly (stormwater can be quite contaminated), when it rains, are all very expensive. In a typical city, there is no spare space to build all these facilities.

Finding opportunities to collect and use stormwater is a worthwhile goal, but it has to be done with economy in mind. An excellent initiative, being practised in Adelaide, Perth and, more recently, in other cities, is to allow stormwater to collect in a pond (where silt and contaminants can settle out), then pump it or drain it into a sandy aquifer or other underground water storage and pump it out later for use. This is called Aquifer Storage and Recovery (ASR) and we should see more of it in future.

More informationhttp://www.environment.gov.au/coasts/publications/stormwater/index.htmlhttp://www.epa.nsw.gov.au/stormwater/hsieteachguide/index.htmhttp://www.melbournewater.com.au/content/drainage_and_stormwater/the_drainage_system/the_drainage_system.asp

Every time it rains, after a dry spell, people ask why we don’t collect stormwater to use in our cities. A quick calculation of the area of a city and the millimetres of rain that fell shows that huge volumes of water were wasted, running into a river or the sea. It seems logical that rainwater collected locally would cost less than water piped in from far away or, worse still, desalinated seawater.

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Ide

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tsRecycle water instead of letting it go to waste in outfalls

Based on a city’s geography, placing sewage treatment plants on the coast and discharging the effluent through outfalls is usually very convenient because the land slopes down to the shoreline. The ocean outfalls are typically designed to ‘diffuse’ (mix and blend) the used water with the seawater, ensuring low concentrations and minimising any environmental impact.

Sending water back up into the community where it came from can be very expensive, in terms of energy, space and pipework. This may make the cost of ‘saving’ the water greater than its value to the community or to a river environment.

A better idea is to intercept sewers inland, at a higher level, and closer to the majority of water users, so that the pumping lift, long pipelines and coastline property costs don’t have to be met.

Even if normal sewage flows can be extracted and treated for reuse, stormflows (which can be up to ten or more times dry weather flow – thanks to rainwater getting into sewers) have to be dealt with; outfalls handle those extra flows well, but reuse of all the water is almost impossible; or at least impractical.

Overall, water and wastewater management decisions need to be made on the basis of a triple bottom line (economic, environmental and social) assessment, minimising cost and environmental impacts, but ensuring that people’s needs are met too.

There are so many factors involved in an ocean outfall system that there can be no single, simple answer and every case must be examined on its merits. Sometimes an outfall is the right solution, while in other cases, much of the sewage can be collected, treated and reused, further inland. Cost and disruption would be the main factors to consider before changing from an existing outfall.

Many Australian coastal communities rely on ocean outfalls to discharge used water (sewage/wastewater/effluent) into the sea. A frequent suggestion is that water should not be allowed to go to waste, but should be recycled for some useful purpose. There is usually an implication that an outfall inherently damages the environment, so it would be beneficial to close it down.

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tsTwice around – Reusing water

Water reuse hasn’t reached its potential yet in Australia. The price of water, in towns and for irrigation, is generally cheap. Town water sells for as little as 50 cents a kilolitre (that’s a tonne of water!) and irrigators pay much less than that; so for someone to purify sewage (used water) and deliver it for reuse, it’s hard to match the price of the original water supply, let alone beat it.

Treated, used water is often far away from potential users, so pipelines and pumps have to be set up to deliver it. It’s often cheaper to discharge to a river or the sea.Although irrigation makes good use of recycled water (it is the most common), there are practical problems: irrigation uses much more water than towns can generate; and some used water has high salt (mainly sodium) levels, which is not good for the soil, so the water must be used with great care, or the salt must be kept out.

In theory, water should be supplied at the quality just right for a given use, no better (a waste of money) and no worse (posing a risk for the users) but, in practice, operating segregated supplies is often complicated and expensive. A growing number of new developments around Australia supply recycled water for people to use in gardens, for toilet flushing, or even for laundry. That second supply is delivered through lilac coloured pipes, to avoid confusion, but there is still a real risk of cross connections, so the ‘second’ quality water has to be safe to drink.

Recycled water is a product which needs good marketing, a good price and effective regulation. Once all these factors are in place, the proportion of water to be reused should increase dramatically.

More informationATSE Water Recycling in Australia 2004http://www.atse.org.au/index.php?sectionid=600

Australia reuses about 11% of effluent (purified, used water), so why not reuse all, or at least, most water? If water can be reused, then it means less water has to be taken from fresh sources and less gets discharged to the environment. At the very least, shouldn’t all effluent be used for irrigation?

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tsDesalination uses too much energy

As desalination is introduced around Australia, there has been a lot of media attention and general discussion about this process. While the current drought and the impact of climate change continue, desalination is likely to be applied more widely and it should be better understood.

Although there are other ways of removing salt from seawater, reverse osmosis is now the most popular, thanks to improved technology, especially energy efficiency. Reverse osmosis is a process in which salty water is forced, under high pressure (about 60 times atmospheric pressure), through a thin, plastic membrane. Microscopic pores in the membrane allow water molecules through, but hold back most salt molecules.

Since the salt in the water is not destroyed, it stays in the ‘reject’ stream and is sent back to the sea where it came from. To avoid any shock to animal life in the discharge area from the concentrated salt (about double the initial concentration), it is sent out via a pipe and through many holes to be mixed into the seawater, ensuring that the normal seawater salt concentration (about 35 grams of salt per litre) is quickly reached.

Desalination does use more energy than most conventional water supply options, but it has one absolute advantage: it is the only non rain-dependent source of water for a coastal community. The most important cost factor in reverse osmosis is the energy to drive the water through the membranes, and that is directly proportional to the salt concentration of the source water. This means that savings can be had if the feed water has less salt in it, perhaps by coming from an estuary or a brackish lake.

Although reverse osmosis does cost more to run than typical surface water supply systems, there is a lot to be said for having a proportion of a coastal town’s water supply provided by reverse osmosis – becoming an absolutely drought-proof back-up source. Reverse osmosis desalinated water is completely safe to drink and, after treatment, tastes like any normal tap water.

More informationhttp://en.wikipedia.org/wiki/Reverse_osmosis

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tsBuild more dams Dams don’t manufacture water, they just store runoff from their catchment areas or water that is pumped or diverted into them. Dams do improve the reliability of water supply and have allowed development of communities in places where they may not have been established otherwise. Increasing a dam’s volume doesn’t necessarily mean it will deliver more water.

Australia has over 500 large dams and more than a million farm dams and other small storages. Most major rivers are dammed at least once, so adding more dams would have little impact. An important consideration on dams is that they often have large surface areas compared to the volume of water stored. For much of Australia, evaporation rates exceed rainfall, so a dam will lose water by evaporation, up to 14mm per day.

Many dams (world-wide) were built for political reasons or in attempts to achieve social outcomes, e.g. to provide irrigation water for farms on which to settle returned soldiers after the two World Wars. Hard-nosed economic considerations were often bypassed, leading to several dams which never paid their way.

Dams can drown valuable farmland and economic activities downstream can be affected; and they can have major impacts on the ecology of rivers and estuaries. Many of the negatives can be eliminated by building off-stream dams; these are constructed on small, intermittent streamlines and filled by pumping from another source.

It is a delicate balancing act to decide when to build a dam. Australia probably has most of the dams it will ever have and future projects will be implemented only after very careful deliberation and consultation.

More informationAustralian Committee on Large Dams http://www.ancold.org.auWorld Commission on Dams http://www.dams.org/ http://www.hastings.nsw.gov.au/www/html/867-cowarra-dam. asp?intsiteid=1

Whenever drought strikes, the call for more dams comes from some community members and commentators. Governments are roundly criticised for having failed to build dams in recent times and wise discussions are conducted on talk-back radio about the merits of extra water storage. The impression is created that a dam somehow guarantees water, regardless of rainfall.

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tsBuild dams near the coast, where it rains more

The performance of a dam depends on: how much rain falls on its catchment (the area that naturally drains into the dam, thanks to topography); the size of the catchment; the storage volume in the dam; the reservoir’s ratio of surface area to volume (i.e. is it broad and shallow or deep and narrow?); and the soil structure and geology (i.e. how much water seeps into or out of the dam, as well as the stability of the area).

Apart from the storage performance of the dam and its safety, there is also the environmental impact to consider, since the dam interrupts natural migration of river creatures up and down, as well as having many other impacts.

Most of Australia’s eastern flowing rivers are short, have small catchments and don’t often have valley shapes amenable to dam construction. Those catchments with good characteristics were taken up with dams some time ago, leaving few new, useful spots to consider now.

Water utilities and state/territory governments have to take all these factors into account when siting dams, which leads to dams being located in spots that aren’t immediately obvious. The wisdom of hindsight is wonderful, of course, and it is easy to criticise dam siting many years afterwards. In the era when many dams in Australia were conceived, the climate was different and engineers’ training and experience led them to infer that the sites they chose were good, long-term positions. In today’s situation of global warming and a better understanding of long-term, natural variations, designers have better tools at their disposal.

More informationThe Australian National Committee on Large Dams http://www.ancold.org.auwww.nlwra.gov.au/atlas

In dry periods a common call is for authorities to build dams close to the coast, where it sometimes rains more than it does inland. This is particularly so on the eastern coast of Australia where the orographic effect leads to much better rainfall east of the Great Dividing Range than on the west. The orographic effect, briefly, means that clouds blowing in from the sea hit the mountains and are forced upwards by the slope of the land and so deposit their water. Sydney, in particular, has good rainfall in the city itself, while the catchment of its main storage, Warragamba Dam, often does not receive the needed rain.

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tsPrevent evaporation from reservoirsA large, shallow dam loses a lot of water to evaporation in summer, especially in hot, inland areas where evaporation far exceeds rainfall and a storage can lose 40% of its volume in a year. It seems logical to cover the water surface somehow and reduce evaporation.

There are ways to cut evaporation losses from water surfaces, using anything from chemical monolayers to modular covers, shade cloth or rafts of floating balls. These methods lead to varying results, depending on local conditions and the size of the storage.

Practical difficulties include the cost of covering and the stability of the covers, especially on larger areas. Tethering sheet covers is difficult and water proof covers tend to pond rainwater on top, creating difficult conditions. A problem in Australian conditions, especially where evaporation is worst, is the impact of sunlight on cover materials: fabrics and plastics tend to break down under the UV wavelengths in our fierce sunlight.

Chemical ‘sealers’ create a layer just one molecule thick on the surface of the water, preventing water molecules from escaping into the air above. Wind tends to spoil the layer, and its life may not be long enough, needing frequent re-applications.

Work by the National Centre for Engineering in Agriculture suggests that floating covers are best for areas less than 1 hectare; shade cloth for up to 5 hectares; and monolayers for over 10 hectares. A cost range of $300 to $500 per megalitre of water saved has been reported. The reduction in total evaporation losses can be anywhere from 5% to 100%, depending on the methods used.

This is a challenging issue and the National Centre for Engineering in Agriculture and the CRC for Irrigation Futures continue to research it actively.

More information National Centre for Engineering in Agriculture http://www.ncea.org.au/ CRC for Irrigation Futures http://www.irrigationfutures.org.au/

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tsDig out reservoirs to increase storage

The first point to note about dams is that the ability of any storage volume to deliver water is only restricted by that volume once an overflow happens; until then, it’s only the inflow and the deliveries that matter. For many Australian dams, overflows rarely happen, so increasing the volume (by whatever means) will not result in any more water being delivered. This means that, unless overflows happen quite regularly, there’s little point in making a dam larger.

In a situation where it is worth increasing storage volume, digging material out of a reservoir is not cost effective. It costs, optimistically, about $10 per cubic metre to cut out soil. Adding a megalitre (roughly half an Olympic swimming pool) to the volume stored behind a dam would cost $10 000. If making dams by digging out material was cost effective, of course, most dams would be built that way, as they could be put in convenient places.

For a significant excavation operation, truck traffic is usually generated, taking the surplus material to where it will be dumped – this is environmentally undesirable.

Another issue to consider is that disturbing the bottom of a reservoir can lead to quality problems in the water, so it’s not done unless really necessary

Finally, a very small increase in the height of a dam wall can create a significant increase in volume. A colourful example is that a line of silicone sealant along the top of the spillway could increase the volume of a large storage by several megalitres.

More information See the other dam references in this book.

Why not dig a hole in a reservoir to increase the storage? Quite a few people have wondered why it’s not feasible to dig out some of the soil from inside a reservoir, increasing its volume. In dry times it seems logical that creating a larger storage would be helpful. Of course, many farmers on flat land build turkey’s nest dams by throwing up a wall around a convenient shape, but that is more a case of creating volume between the walls than it is one of excavating all the volume needed.

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tsWe can always count on groundwater

Groundwater has been collected in sand or cracked rock aquifers (water-holding spaces under ground) sometimes over millions of years. Rainwater percolating down through the soil fills aquifers; some have very fresh water in them, but others contain water that’s hundreds of thousands of years old.

About 20% to 30% of all Australia’s water needs are supplied by groundwater, mostly in the bush. The cities of Perth (50%), Newcastle (25%) and Alice Springs (100%) depend on groundwater too. Getting groundwater out requires a bore or well, usually drilled by a truck-mounted rig and fitted with a lining pipe and a down-hole pump.When the bore pump is operated, it draws down the water level and water from the aquifer around the bore starts to move in, under gravity’s pull, to fill the space. If the bore is pumped too hard, it may never recover.

Despite Australia’s many bores, we don’t have a uniformly efficient management system in place to manage the extraction process. Bores should be licensed and logged; their extraction rates measured and any over-extractions policed. In practice, some states have good management and monitoring systems, while others don’t.

Much better management systems are needed to bring the system into balance – allowing responsible users to rely on their bores permanently, rather than exploiting them now and not bothering about the future.

To make life a bit more complicated, aquifers often connect rivers with groundwater, so extracting groundwater can drain a river. This is called conjunctive use, and it needs to be monitored and controlled too, so we don’t fool ourselves with extractions that will destroy both rivers and aquifers.

More informationhttp://www.watercare.net/wll/wc-groundwater.html

Although groundwater is not well understood, people quite commonly believe that it’s a free resource, to be tapped conveniently and informally. Around Australia, millions of bores have been put down, and more are being sunk every day, so each farmer or householder can tap into this resource.

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tsA national water grid This is a tantalising myth for people who are interested in pipes, tanks and pumps, but who do not understand the economics of water and pipelines very well. An extensive grid of pipes would be enormously expensive (many billions of dollars), and delivering water a long distance through a grid of this type would also be very costly. Unlike gas and electricity, which can be cost effectively transported over thousands of kilometres, water is heavy, incompressible and generates a lot of friction when moving.

There is no particular reason why having a grid should improve water management. The natural layout of catchments, rivers and rainfall patterns, together with where people live and farm all combines to make some pipe connections sensible and others meaningless. The earning potential of water is important but it has upper limits, so investing massively to collect slightly more water than we do now would not earn enough to pay its way.

In spite of all those negatives for an overall grid, there are circumstances when one or more pipelines make sense to connect one region to another. There is no clear distinction between a local grid which would be viable and a regional one which simply would not work; every case has to be examined on its own merits and all the benefits and costs weighed up.

A recent example is in SE Queensland, where a regional grid will link about 13 different communities, allowing them to distribute water to where it’s needed most. It will serve millions of people at a reasonable cost – an effective, local system.

Other sources of informationTalking Water, p 104http://www.farmhand.org.au/

A water grid across Australia has been suggested to link up groundwater and surface water sources and allow us to deliver water from dry areas to wet areas, as well as storing runoff water underground (in many tanks) for later use. One version of the Water Grid consists of pipes laid 1km apart; others include for covering either the whole country (7.6 million square km) or just the current land area that’s used for farming.

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tsTurning rivers back inland

A river is a complex, natural system, starting as a spring or creek in the hills and changing its size and character as it flows down to the sea. Along a river’s length, there are vigorous interactions between the flow, the soil, animals, fish, plants and sunlight. Different ecosystems flourish in different parts (the bottom, the banks, and in the riparian strip [land close to the banks]) and the food chain keeps them all going. Some fish migrate up and down rivers to spawn or to grow and they need free passage along the river’s length to do that.

The most productive area of a river is where it becomes a shallow, wide estuary on meeting the sea, and the blending of fresh and salt water stimulates mangroves, shellfish and other plants and animals.

Floods or freshes (minor floods) are critical for rivers; they move sediments and food along; water trees and the floodplain; and generally stimulate life in and along the river. Silt deposited on the floodplain helps keep the area fertile.

A river is not just a drain carrying precious water out to sea – it is actually a vital, living system which needs all its variety and most if not all of its water to sustain its ecosystems. Diverting a river and pumping the water back inland can destroy the river’s whole character. Most rivers can tolerate some flow extraction, without major ecological damage. There are no hard and fast rules on the amount, but figures of up to 15% or 20% of the water are sometimes used. Complete diversion and reversal of a river’s flow would destroy most of the features that people value in it.

More informationhttp://www.lwa.gov.au (Land & Water Australia)http://www.ewatercrc.com.au/ (ewater CRC)http://www.healthywaterways.org (Healthy Waterways Partnership. South East Qld)

For many years, the suggestion has been made that various rivers could be profitably reversed, so that their water would not be wasted by flowing out to sea. The water so collected could be used for communities nearby, or for irrigation. This idea has been put forward for the Clarence River in northern NSW, for example.

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tsWe need drip irrigation for all crops

Shouldn’t farmers be using drip irrigation for all their crops? It is much more efficient and would save a lot of water.

Drip irrigation is, indeed, very efficient. It can use anywhere from 30% to 50% less water than an old-fashioned flood irrigation system. Installing drip irrigation can cost up to $10 000 per hectare, so a farmer must be confident that the extra production achieved, together with water savings, will pay for that investment. Some crops simply don’t earn enough to justify investing in drip irrigation. Typically, fruit trees and grape vines use drip irrigation, but fodder usually doesn’t, while cotton growers are experimenting with drip irrigation.

Apart from the cost, soil type affects the value of moving to drip irrigation; some soils are easy to manage with flood irrigation and no gain would come from moving to drip.Other factors to do with managing irrigation can help improve efficiency a lot too; like better scheduling and moisture monitoring.

There are other irrigation methods, in between flood and drip, which are more efficient than flood but which don’t cost as much to install as drip. These include jets, sprinklers and rotating or traveling distributors. Some methods work better with some crops than others and, as always, the overall cost is a key factor.

Drip irrigation uses buried or exposed plastic pipes, with tiny drippers placed to deliver regular drips to the roots of the crop. It suits ‘standing’ crops (trees and vines) best, since they don’t get ploughed up regularly. For annual crops, it’s feasible to use cheaper, buried ‘tapes’ (flat tubes installed up to six rows at a time) which might last a few seasons, provided ploughing and planting among the tapes is done with care.

Scientific irrigation is complicated, so choices are also not as obvious as they might seem. Modern irrigation farmers are very scientific, as well as being astute business-people, so they analyse their options carefully and invest in just the right level of technology – be it drip or something cheaper.

More informationCRC for Irrigation Futures http://www.irrigationfutures.org.au/Irrigation Association of Australia http://www.irrigation.org.au

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tsFarm in the north, where the water is

There are several reasons why farming in the far north is not as attractive as might be expected:

1 High average runoff conceals the reality of highly variable rainfall, meaning a long dry period and very short periods of intense rainfall. This means large storage volumes are required and irrigation has to be practised instead of rainfed farming.

2 Farm workers are not always keen to live in tropical, remote places.

3 Getting produce from remote farms to markets is expensive which means that the benefits of plentiful water may be lost through increased freight costs.

4 Crops and their pests often behave differently in tropical conditions than they do in the more temperate zones of Southern Australia. Rice failed in early attempts in the NT (geese raided the crops, decimating them). Sugar did not grow as well in the Ord as expected, but cotton, initially weak, has improved, owing to genetically modified strains, designed for the tropics.

5 Many rivers in the far north are currently undisturbed, and indigenous communities have strong cultural affinities with them; so introducing dams and farms is likely to be controversial.

Despite the challenges, the lure of farming in the ‘wet’ north remains, so work is being done to identify problems and solutions. The CSIRO is carrying out a major project to identify the potential for sustainable agriculture.

Further informationAustralian Water Resources Assessment 2000

This is a compelling idea, because there are areas in the far north of Australia where runoff is much higher than elsewhere. For example, 24.5% of total runoff comes from the Gulf of Carpentaria Basin, while just 6.1% comes from the Murray-Darling Basin, one of Australia’s key agricultural areas.

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tsWater supply from the north

Water is surprisingly heavy. A kilolitre, (one thousand litres) weighs a tonne, so it takes a lot of energy to move it around – even on level ground. Pushing water through a pipe needs energy to overcome frictional resistance and it takes pump power to drive the water through. If, in addition, the pipeline has to climb up a mountain range, it takes extra pump energy to lift the water. All this adds up to being very costly.

The faster the water flows, the more the frictional resistance it generates. However, the bigger the diameter of the pipeline (and the smoother the walls) the less energy is needed; but large pipes cost more; so the design of a pipeline is a balance between pumping energy costs and pipeline costs. Maintenance costs have to be considered too.

One of the additional costs that is sometimes overlooked is that of accessing the water in the north. While it certainly rains more, the rainfall patterns are highly variable (monsoonal) and a year’s runoff might happen over just a few days. It would need a huge dam storage to even out this flow variation and ensure a steady supply. Dams are also very expensive, not to mention their likely adverse impacts on the local landholders and the environment, and evaporation losses during the dry season.

Some of our northern rivers have especially valuable ecosystems; the local needs for the water must also be considered and, all in all, getting water from the north is not as easy and cheap as it might seem at first glance.

Current studies are showing that local options (water conservation, desalination, recycling, etc) cost around $1 to $2 per kilolitre, but a supply from, say, 1 500 km away would cost of the order of $5-6 per kilolitre.

More informationTalking Water p98 http://www.farmhand.org.au/

Shouldn’t we pump water from northern Australia to make up for the diminishing supplies in southern Australia? It rains a lot more up there (about 70% of the continent’s runoff comes off the north) and we could use the water for farming and cities in the south.

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tsShipping water in tankers

Tankering products is a well established technology, but normally for high value products, like oil. The cost of operating a tanker is high and there is also the need for loading and offloading facilities, as well as connecting to the water source and the destination network at the ends of the tanker’s run.

An estimate conducted by the Kimberley Water Expert Panel (which investigated options for moving water from the Kimberleys to Perth, Western Australia) in April 2006, concluded that using supertankers to deliver water on that 3 000 km route would cost $6.70 per kilolitre and would consume more energy than all other options. A recent media article suggested that a hybrid, ‘solar sailer’ tanker could ship water using renewable energy; that is a noble idea, but years away from implementation at a large scale.

In situations where so-called back-loads of water could be carried by ships usually used to deliver some other commodity, tankering might be effective. For example, ore carriers deliver bauxite ore from Kwinana in Western Australia to Bell Bay in Tasmania. Since they would normally travel back to Kwinana empty, there is only a small extra cost for using them to bring water back from Tasmania. The ships would have to be modified to carry the different cargoes, but there would be little or no incremental energy consumption (the ships need ballast anyway).

As is so often the case, this is a horses-for-courses situation: under the right conditions, tankering water by sea might be a realistic proposition, but generally, other options would be cheaper and use less energy. A benefit of tankering is that it can be done only when needed, provided tankers are available.

More informationOptions for bringing water to Perth from the Kimberley, 2006 http://portal.water.wa.gov.au/portal/page/portal/PlanningWaterFuture/Publications/KimberleyWaterSource/Content/Finalreport_000.pdf

An interesting idea is that of shipping water from wet places to dry places, using tankers, either purpose-made, or adapted from oil tankers, which are no longer allowed to have single-walled tanks. South west Tasmania has been a particular target as a source for tankered water, while northern, wet areas have been considered too.

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tsMoving water long distances by canal

Because canals can be built with large cross sectional areas, they are more effective than pipes in terms of energy needed to move a large volume of water. Canals are usually wider than they are deep, they are often lined with concrete, and they have gently sloping sides, for stability.

There are many factors involved in designing and operating a canal: provision has to be made for it to cross over or under roads, rivers and other obstructions; unless the ground slope is ideal, pump stations are needed to lift the water up at intervals; provision has to be made to prevent evaporation losses and to keep animals or people from falling in; if anything goes wrong in the system, there has to be somewhere to collect and store the water which was running along the canal; by its nature, a canal has to follow natural land contours much more closely than a pipeline; so is often much longer than an equivalent pipeline; to prevent seepage and to minimise friction, a canal usually has a smooth concrete lining, which is expensive; dealing with silt in a canal is a problem - deposited from the flowing water, blown in by wind, or washed in with stormwater.

All these factors add to the cost of a canal. For a recent proposal to deliver water from the Kimberley to Perth, the canal option was judged, by an independent expert panel, to cost 22% more than a pipeline (and both options were much more expensive than other alternatives).

For relatively short distances, across favourable country, canals can be cost effective but, as distances increase, competitive advantages are reduced. Exactly when a canal is competitive or not depends strongly on local circumstances.

More informationhttp://dows.lincdigital.com.au/Kimberley_Water_Source.asp

A common suggestion associated with water supply schemes is moving water long distances through canals. For a long time, all over the world, canals have been used, often more for transport than to move water. A canal can move a lot of water without much energy to drive it; a very small slope is enough to make the water move along under gravity. For a large canal a drop in level of as little as 100 mm in a kilometre could be enough to keep it flowing.

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tsTowing icebergs from Antarctica

Careful scrutiny of this idea over the years has generally shown it to be impractical. Moving an iceberg from cold to warm water will make it start melting. For an iceberg to survive the trip from Antarctica to Australia, it would have to start at least in the 300 – 500 million tonne bracket, but there are no ships capable of towing a load of that size. A different source, however, suggests that a 30 million tonne iceberg would be a workable size, and discusses pulling it with tugs.

Moving icebergs around could have detrimental impacts on the ecosystems in Antarctica, and setting up systems to collect water from icebergs on arrival would also be very challenging. One solution was to wrap the whole iceberg in plastic, then pipe away the water which melted off it. If that notion could be converted to reality, the risk of pieces of plastic being shredded and floating around as a threat to animals in the ocean would have to be addressed.

The ‘tip of the iceberg’ factor, i.e. that 90% of its height would be below sea level, means that bringing an iceberg close to shore would not be possible. One study suggested that it would only be feasible to travel as far as the continental shelf, needing docking and/or storage structures to bring water in from there. The risk of a stray iceberg smashing bottom-living organisms along the coastline has to be considered as well.

A South Australian Government study in 1989 suggested that the cost of a scheme to bring icebergs to SA would cost about $1.8 billion. Allowing for inflation since then, the unit cost of water would be $3.20 per kilolitre, assuming it was achievable.

More informationTalking Waterhttp://www.smec.com.au/development/quantum/icebergs.htm (this reference mentions an iceberg weighing 30 tonnes – it should read 30 million tones)

This is a romantic notion – icebergs being towed from Antarctica to dry countries, then melted down to produce water on arrival. The Antarctic ice shelf produces some 1,250,000 gigalitres of water as ice each year (Australia uses around 24,000 gigalitres a year). It seems tantalisingly simple, so why haven’t governments taken the hint and solved our water problems?

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tsDrain seawater from Spencer Gulf into Lake Eyre

There are several reasons why this is not likely to happen. Firstly, the profile of the landscape between the Gulf and the Lake includes about 350 km of land crossing, at elevations of up to 150 m. It would probably best be tackled with a pipeline up to the top level, followed by gravity flow along a canal to the lake. An investment of that size would only be warranted if there were guarantees of positive, profitable outcomes from the project overall. Estimated project costs have been many billions of dollars.

The ecology of Lake Eyre is unique in that it drains the largest basin in the world (1.2 million square kilometres) and many species have adapted to the situation. When, quite rarely, rains up north lead the Lake to flood, there is an explosion of bird and other wildlife populations. Imposing a steady seawater flow on that ecological system would have profound impacts and would probably lead to the destruction of much of the habitat or at least to major changes to its character.

From a cultural and archaeological point of view, too, Lake Eyre is unique, and interfering with its natural balances would not be an acceptable action.

On the front of creating improved local conditions, there is little evidence that there would, in fact, be any improvement in rainfall. Neither the Spencer Gulf nor the Red Sea has been found to improve climatic conditions in their regions, so Lake Eyre could be expected to be equally unaffected.

More informationTalking Water

This is one of the bolder ideas mooted for Australia and water; the notion is that, since Lake Eyre is 15 m below sea level, it should be possible to cut a canal or run a pipe which would allow seawater to fill Lake Eyre. The presence of all the water would, hopefully, lead to a change in the local climate, with more rain. A sub-idea is that desalination could be used to produce freshwater from the newly salty lake.

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tsCloud seeding can supplement our water resources significantly

Every so often, the idea of cloud seeding to augment water supplies comes up, and it has some enthusiastic supporters. State governments are sometimes criticised for failing to make more use of this technology.

Cloud seeding involves spraying small particles into clouds – these act as centres for the formation of droplets, to make rain fall. Aircraft normally spread the particles (silver iodide, other salts, smoke or dry ice pellets). Cloud seeding doesn’t create rain clouds; it encourages existing clouds to deposit their moisture. It’s also worth noting that rain induced by cloud seeding may just be moved from one location to another, with no net gain in rainfall overall.

The history of cloud seeding in Australia includes large-scale cloud seeding trials in numerous locations. By and large, those trials produced results that were inconclusive at best. The American National Academy of Sciences also concluded in October 2003 that convincing scientific proof of the efficacy of intentional weather modification efforts was still lacking.

The CSIRO has shown that, in Australia, cloud seeding is effective in only a limited number of weather conditions, in certain locations. Tasmania is a case in point, where cloud seeding has yielded reliable results and cloud-seeding operations have been undertaken by Hydro Tasmania since the 1960s. The CSIRO has largely stopped its active research effort after more than thirty years, owing to inconclusive results (and other research priorities) although it keeps watch over cloud seeding developments. The CSIRO has concluded that cloud-seeding is unlikely to be effective during winter and spring over the inland plains of southern and eastern Australia, and similarly ineffective during summer over eastern and north-eastern Australia and immediately to the north of Perth.

Overall, there are opportunities for positive results for cloud seeding in some parts of Australia, but the practice has to be carefully assessed and is by no means a magic bullet.

Sources of informationTalking Waterhttp://www.hydro.com.au/search/search.cgi?query=cloud+seeding&collection=External(or visit www.hydro.com.au and search for cloud seeding)

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tsThe price of water is wrong; it’s too cheap (or too expensive)

Householders in Australia pay anywhere from 50c to $1.50 for a kilolitre (1 000 litres – a tonne) of water. At a selling price of about $1 per kilolitre, most water suppliers (councils or water authorities) are able to stay in business. Not all are making enough profit to replace old equipment and pipelines, though, and the ‘book’ value of their assets may be too low (which means that refurbishing costs could be difficult to manage later).

Also, at about $1 per tonne, mains water in towns is far and away the cheapest product available; so not all customers pay much attention to how much they use. If the price was higher, several good results could be achieved: people would be more conscious about how much water they use (and so conserve water); water businesses would be able to invest more in replacement programs; and more environmental protection activities could be funded from profits.

Farmers pay much less for water, since it’s not treated and generally not piped to them under pressure. The price is intended mainly to cover the cost of dams, pipes and channels to collect, store and deliver the water, as well as for managing rivers. Often, irrigator water prices don'tactually cover all the water suppliers’ and managers’ costs, so a state subsidy is needed to keep them going.

Irrigators are now able to trade water (a bit like a stock exchange, but for water instead of company stocks) so they can sell their licensed allocations if it suits them, or buy from other farmers if they need more than they have. They can sell their licences permanently or they can do ‘temporary’ trades – just leasing their allocation for one or two seasons. Permanent water can sell for nearly $2 per kilolitre, while temporary water prices vary enormously, from 50c to a dollar or more.

More informationIPART, NSW www.ipart.nsw.gov.auAustralian Academy of Technological Sciences and Engineering http://www.atse.org.au/index.php?sectionid=217

Nothing can start a fiery discussion as well as water pricing. Farmers often feel they pay too much, while environmental advocates generally feel that everyone should pay more. Some people, though, don’t know what they pay for water anyway; it’s too cheap to register.

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AquiferA layer of underground porous rock that stores and transports water.

Catchment The area of land drained by a creek or river system.

CanalMan-made waterway connected to lakes, river or the ocean, used to deliver water.

Cloud seedingThe attempt to change the amount or type of rain that falls from clouds.

ContaminationThe introduction of substances into water in a concentration that makes it unfit for its next intended use.

DamA barrier constructed across flowing water that controls the flow to create a reservoir, lake or impoundment

Desalination Removal of salts from seawater or other saline solutions.

DischargeThe release of liquid into receiving waters (river, stream or ocean).

DisinfectionTreatment of polluted or contaminated water to destroy disease-causing organisms.

Distribution system

A network of pipes leading from a water supply to customers' plumbing systems.

EstuariesA semi-enclosed coastal body of water with a free connection to the open sea.

EffluentOut-flowing liquid from a body of water or a man-made structure, such as wastewater treatment plant.

EvaporationThe process whereby a liquid becomes a gas due to heating.

ExtractionThe process of taking water from any source, either temporarily or permanently.

FiltrationThe separation of solids from a liquid by passing the liquid through a porous substance.

FreshesRiver flows that result in a rise in river height for a short time, due to bursts of rain.

Global warming

The gradual increase in global temperatures caused by the emission of gases that trap the sun’s heat in the Earth’s atmosphere.

HeadwatersSmall creeks at the uppermost reaches of a stream system, often found in the mountains.

IcebergA large, free-floating piece of ice that has broken off from a glacier or ice shelf.

InundationFlooding; the rising of a body of water and its overflowing onto normally dry land.

IrrigationReplacing or supplementing rainfall with water from another source to grow crops.

MonolayerLiquid applied to the water surface to act as a barrier to reduce evaporation.

Orographic effect

The mechanical lifting of an air mass over mountains that enhances or results in rainfall.

RecycleTo use water more than once before it passes back into the natural hydrologic system.

Renewable energy

Energy obtained from sources that are naturally and continually replenished, eg. wind.

Reuse waterTreated wastewater that is used for beneficial purposes, including irrigation.

ReservoirA place where water is stored; a pond, lake or basin, either natural or artificial.

Reverse osmosisA membrane filtration process that allows only the passage of water; can be used for desalination or where water of high purity is required.

Riparian Relating to an area along the banks of a stream or adjacent to a watercourse or wetland.

Run offRain or water that flows off the land into a river, stream, lake or reservoir; stormwater.

SewerA system of underground pipes that collect and transport wastewater from buildings to treatment facilities or streams.

SpillwayA structure that diverts flood flows over or around a dam, to protect the dam.

TankersA very large ship built to transport very large quantities of liquids.

Water gridA network of two-way pipelines to connect all major bulk water sources in a region.

Water tableThe level below ground at which the subsurface material is fully saturated with water.

Water tradingThe process of buying, selling, leasing water access entitlements or water allocations.

Water words

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MORE SOURCES OF INFORMATION ABOUT WATERGovernment Bodies

Australian Government

www.dew.gov.au Department of Environment and Water Resources

www.nwc.gov.au National Water Commission (National Water Initiative)

www.bom.gov.au Bureau of Meteorology

www.lwa.gov.au Land & Water Australia (research)

www.csiro.au CSIRO (research)

www.abs.gov.au Australian Bureau of Statistics

www.mdbc.gov.au Murray-Darling Basin Commission

ACT Government

www.environment.act.gov.au

NSW Government

www.dnr.nsw.gov.au Department of Natural Resources

www.deus.nsw.gov.au Department of Energy Sustainability and Utilities

www.waterforlife.nsw.gov.au Metropolitan Water Plan for Sydney

www.epa.nsw.gov.au NSW Environment Protection Authority

www.statewater.com.au State Water (manages rivers)

Northern Territory Government

http://www.nt.gov.au/nreta/ Department of Natural Resources Environment and theArts

Queensland Government

http://www.nrw.qld.gov.au/ Department of Natural Resources and Water

www.qwc.qld.gov.au Queensland Water Commission

www.epa.qld.gov.au Queensland Environmental Protection Agency

South Australian Government

http://www.dwlbc.sa.gov.au/ Department of Water, Land and Biodiversity Conservation

Tasmanian Government

www.dpiw.tas.gov.au Department of Primary Industries and Water

Victorian Government

www.dse.vic.gov.au Department of Environment and Sustainability

www.esc.vic.gov.au Essential Services Commission (pricing and performance)

Western Australian Government

http://portal.water.wa.gov.au/portal/page/portal/home Department of Water

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Water Suppliers (Cities)

There are more than 300 water suppliers across Australia, so we cannot list them all here, but the capital city list is given below; it covers more than half the population. Adelaide www.sawater.com.au Brisbane www.seqwater.com.au http://www.brisbane.qld.gov.au/BCC:BRISWATERL:1193307793:pc=PC_1392 Canberra www.actew.com.au Darwin www.powerwater.com.au Hobart www.hobartwater.com.au; www.hobartcity.com.au Melbourne www.melbournewater.com.au; www.citywestwater.com.au; www.sewater.com.au; www.yvw.com.au Perth www.watercorporation.com.au Sydney www.sydneywater.com.au; www.sca.nsw.gov.au

Associations/NGOs

ACF www.acfonline.org.au ANCID (irrigation) www.ancid.org.au ANCOLD (dams) www.ancold.org.au Australian Water Association www.awa.asn.au Irrigation Association www.irrigation.org.au Murray Darling Association www.mda.asn.au NSW Irrigators’ Council www.nswirrigators.org.au NSW Water Directorate (100+ NSW councils) www.waterdirectorate.asn.au Victorian Water Industry Association (20 Victorian utilities) www.vicwater.org.au Water Services Association (major utilities) www.wsaa.asn.au WWF www.wwf.org.au WIOA (operators) www.wioa.org.au

Books

Australian Water Resources Assessment 2000 http://audit.ea.gov.au/anra/water/docs/national/water_contents.html Talking Water, Farmhand Foundation 2004 Watershed, Ticky Fullerton, ABC Books 2001