The idea: moving water from northern Australia to southern Australia 3




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Water for the Future


Moving water long distances: Grand schemes or pipe dreams?


Table of Contents


The idea: moving water from northern Australia to southern Australia 3


How would water be diverted and moved? 5


Where would the water come from — and is there enough? 7


Is moving water from the north to the south possible? 9


Proposals for moving water 9


What does all this mean? 14


Water for the Future 15


Alternatives to diverting water — what else can we do? 15


References 19


Glossary 21


Moving water long distances: Grand schemes or pipe dreams?

Published by the Department of Sustainability, Environment, Water, Population and Communities

GPO Box 787

CANBERRA ACT 2601

ISBN is 978-1-921733-06-2

© Commonwealth of Australia 2010


Information contained in this publication may be copied or reproduced for study, research, information or educational purposes, subject to inclusion of acknowledgement of the sources.


Requests and inquiries concerning reproduction and rights should be addressed to Commonwealth Copyright Administration, Attorney General’s Department, Robert Garran Offices, National Circuit, Barton ACT 2600 or posted at http://www.ag.gov.au/cca


The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for Sustainability, Environment, Water, Population and Communities.


While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication.


I love a sunburnt country,

A land of sweeping plains,

Of ragged mountain ranges,

Of drought and flooding rains.


Dorothea Mackellar (“My Country”)


Dorothea Mackellar’s famous poem captures our love of Australia’s landscape. But, it also captures one of our greatest challenges: how to manage our water. Australia is the driest inhabited continent,1 and its rainfall varies greatly from year to year and place to place.2 This means that our water supplies can be scarce and unreliable.


Water management is sometimes a controversial topic in Australia — one that generates strong debate and big ideas. This publication looks at one of these big ideas: moving water long distances from northern to southern Australia. It covers the possible costs and benefits of various options, as well as other alternatives for securing water supplies.


The idea: moving water from northern Australia to southern Australia


News reports often show farmers in southern Australia battling drought, while the towns and cities of the north are inundated with ‘flooding rains’. About 70 per cent of Australia’s runoff occurs in northern Australia,3 and climate research predicts that water scarcity in southern Australia will intensify.4 These facts, along with the existing water pipelines across the country, have led people to suggest that water could be harvested from rivers, streams or storage dams in northern Australia, and transported south, using trucks, ocean tankers, canals or pipelines.


Key facts


• Moving water long distances is costly, energy intensive, and can have significant environmental, social and cultural impacts.


• Using water that is locally available is generally more cost effective than transporting water long distances. Current studies show that local options, such as water conservation, desalination and recycling, cost around $1–2 per thousand litres; a supply from 1500 kilometres (km) away would cost around $5–6 per thousand litres.5


• Much of northern Australia can be described as ‘annually water limited’. This means that in general, more water is lost every year through evapotranspiration than falls as rain.6


• Most rainfall in northern Australia falls near the coast, not in river headwaters, and runs off to the sea.


• The landscape across much of the north is gently undulating and at a low elevation, presenting few opportunities for surface water storage such as dams.


Has it been done before?

In particular circumstances and places, pipelines can be a useful way to improve the availability and reliability of our water supply. Significant infrastructure projects that transport water have previously been undertaken. However, none have been on a scale that would move large volumes of water for such a distance as from northern to southern Australia.


Past large-scale projects include the early 1900s 530 km Kalgoorlie Goldfields Pipeline, and the 1960s Snowy Mountain Hydro-Electric Scheme. Many shorter pipelines also exist in Australia. For example, pipelines carry water from the Murray River in South Australia to other parts of the state.


The longest of these (from the Murray River) is the 356 km Morgan to Whyalla pipeline, built in 1944. It can transport 206 megalitres (ML) of water a day. Pipelines have also recently been built in response to drought; a 105 km pipeline moves water from the Stirling Dam on Western Australia’s Harvey River to Perth.7


How much water?


Litre (L): the volume of water in one-thousandth of a cubic metre. One litre weighs about one kilogram.


Kilolitre (KL): 1000 litres or one cubic metre of water. One kilolitre weighs about one tonne.


Megalitre (ML): one million litres or 1000 cubic metres of water, weighing about 1000 tonnes. An Olympic swimming pool holds at least 2500 cubic metres or 2.5 ML.


Gigalitre (GL): 1000 million (or one billion) litres of water or one million cubic metres. One gigalitre of water weighs about one million tonnes. Sydney Harbour holds more than 500 GL.


The Snowy River Scheme

The Snowy River Scheme is a major river diversion and a successful largescale infrastructure project. A system of reservoirs, aqueducts and tunnels captures water from the upper reaches of the Snowy, Murray and Murrumbidgee rivers, diverting it for use in irrigation and electricity generation. Almost the entire flow of the Snowy River is diverted west. Legislation to begin the scheme was passed in 1949, and it was completed in 1974.


Australians are proud of the Snowy Scheme. It helped to shape our history, with thousands of new migrants beginning their life in Australia working on its construction. The Snowy Scheme, one of the engineering wonders of the world,8 increased the availability and reliability of water in the west; this allowed the development of irrigation-based farming.9


Despite the significance of the Snowy Scheme, it is important to recognise its environmental impact. The scheme has reduced the Snowy River headwaters to around one per cent of their original flow. The upper reaches of the Snowy River, and other mountain rivers diverted by the scheme, are severely degraded. The reduction in flow has impacted greatly on aquatic fauna and flora; temperature regimes have changed, triggers for fish breeding have been removed, and the lack of flushing water flows has resulted in a loss of habitat.


Pools have filled in as organic material and nutrients have accumulated. Sediment build up in the middle reaches of the river has destroyed habitat and changed the flow pattern of the water, and seawater intrusion in the lower reaches now affects local landholders many kilometres upstream from the river mouth.10


Scientists estimate that to return the Snowy River to a healthy state, its flow should be returned to a minimum of 28 per cent of its original level. In 2002, the New South Wales, Victorian and Commonwealth Governments signed the Snowy Water Inquiry Outcomes Implementation Deed. This outlines a process to return 21 per cent of average natural flow to the Snowy River over 10 years, with the option of increasing this to 28 per cent after 2012.11


How would water be diverted and moved?


Pipelines

The most commonly suggested method of transporting water is through a concrete and steel pipe, running either above or below the ground. Regular pumping stations would be required to maintain the pipeline’s flow over a long distance.


Pipelines minimise the amount of water lost to evaporation, because the water is not exposed to air or sunlight. Pipelines can also help to maintain water quality. However, the water may still need to be treated at both the source and at the end point, with any treatment processes adding to the significant energy and greenhouse costs of piping water.


A pipeline from the north to the south of Australia would rate among the longest water transfer projects in the world. Some people have suggested that pipelines could supply water to towns and agriculture along the way, for irrigation, native vegetation, or town and community water supplies. The economic, environmental and social costs of pipelines and other water transport options all vary, depending on factors such as the amount of water to be diverted, and the path the pipeline would take.


A report to the Western Australian Government about piping water from the Kimberley to Perth found that it was not an economically viable option. The cost of water transported through a pipeline or canal, in that instance, would be between 100 and 200 times more than normal prices for bulk water.12


What about gas pipelines?


Many people see long gas pipelines, and wonder why similar pipelines aren’t built for water. Although water is much less expensive than gas, it is much heavier, and therefore requires much more energy to move. For example, you can buy a nine kilogram (kg) cylinder of gas for about $30 from your local service station and easily carry the gas home. But imagine that you decided to buy water instead. For $30, assuming you paid the same price as you pay for water from the kitchen tap, you’d have to transport about 42 000 L of water — enough to fill a backyard swimming pool!


Trucking and shipping water

Trucks or ocean tankers could be used to transport water from the north to the south. These options would have large operational costs and energy requirements, and would generate large amounts of greenhouse gases. Trucks are often used to transport water to towns in times of drought. However, this is only viable as a temporary water supply option and when carting over short distances.


Canals

Some people have suggested that water could be transported long distances across Australia by canals, which are open channels cut through the land. A small slope can be enough for gravity-fed movement of water through a short canal. However, as is the case for pipelines, pumping would be required to move water through canals over longer distances.


A canal needs to follow the contours of the land. This means it tends to be much longer than a direct pipeline. For example, a direct coastal route from the Kimberley to Perth is 1900 km long, but a canal would have to follow a 3700 km long route. A canal would also need to pass over or under roads, rivers and other obstructions. See Figure 1 for the length of other options.


Canals lose water through leakage and evaporation. A 3700 km long canal from the Kimberley to Perth could lose 93 GL per year to evaporation, and a further 125 GL per year to leakage, even if the best lining techniques are used. To account for these losses, such a canal would need to draw at least twice as much water as is needed for consumption.


To prevent seepage and minimise friction, canals are often lined with concrete. Fencing may also be required to help minimise water contamination, or to provide safety barriers. These factors add to the expense of canal construction. Canals leave a lasting and permanent mark on the land, and they change and disrupt natural water flows.13


Figure 1: Diagram comparing distance of some proposed and existing projects to transport water





Where would the water come from — and is there enough?


Proposals to transport water from northern Australia vary, but they all rely on excess water being available for extraction. This depends on a range of factors, including:


• the reliability of rainfall across northern Australia


• the current and likely future availability of water in northern Australia


• the current and potential future uses of the north’s water resources


• the practicality of capturing and storing water before being diverted, and


• environmental, cultural, economic and political considerations.


Rainfall in northern Australia

Rainfall patterns in northern Australia are very different from those in southern Australia. The seasons of the northern Australian tropics can be loosely divided into two distinctly different periods — wet and dry.


During the dry season, which lasts up to nine months of the year, there is little or no rain. In fact, in many parts of northern Australia, evapotranspiration is higher than rainfall for most of the year.14 Water scarcity can be an issue for communities and ecosystems. People living in the tropics use dams and bores for their water supply to cope with these unreliable and seasonal rainfall patterns.


During the wet season, the north can receive extreme rainfall from thunderstorms, monsoon depressions and cyclones. For a few months each year, more rain falls than is lost to evaporation. This rainfall accounts for around 65 per cent of Australia’s total water runoff. The north’s annual runoff can occur over just a few days. Most of this water runs to the sea, but some plays an important role in the annual recharge of aquifers (geological formations that hold groundwater).15


When people hear that a large amount of Australia’s rainfall runs off into the ocean, they sometimes think that this water is ‘wasted’. However, it is important to remember that this water is vital to the health of ocean ecosystems and estuaries. Also, because rainfall in the north is highly variable, both within each year and from year to year, estimates of annual average rainfall for the north can be quite misleading. A single extremely wet year can dramatically increase the long-term average.16


Rivers and catchments in northern Australia


Northern Australia has the largest area of unregulated rivers and catchments (those without dams or water extraction) in Australia. Most estuaries are in a near pristine condition, because human land use has had minimal impact, and pests and weeds are not widespread.17


Floods are vital ecosystem events that flush nutrients into the near-shore marine environment and provide on-shore breeding grounds for marine creatures. When water flows over riverbanks and across floodplains, it fills hollows and pools that persist throughout the dry season. This sustains vital ecosystems that provide refuges for birds and animals until the next wet season.18 Large amounts of runoff can also trigger waterbirds to breed, and fish to spawn and migrate.19


The health of northern ecosystems has direct economic implications for the value of northern fisheries. Just one of these, the Northern Prawn Fishery, is worth up to $164 million per annum.20

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