It promises an extra 100 billion litres (GL) of secure environmental flows to rivers like the Murray and the Goulburn and some of that will find its way into the newly created River Red Gum parks! But it’s a very expensive way of returning water to rivers…
There’s no disputing that the Goulburn-Murray irrigation system is an amazing feat of engineering – thousands of kilometers of channels fed entirely by gravity over a gradient of about 200 metres. But it’s also wildly inefficient and has been estimated to lose up to 800 GL a year through evaporation, leakage and seepage. Water is precious and wasting it is unacceptable – that’s why it’s important to modernise our irrigation systems. The trick is working out how much money should be invested in modernisation versus water buy-back for the environment, and which parts of the irrigation system should be modernised and which should be retired from irrigation for good.
The announcement from the federal and state government will see over $2 billion invested in irrigation modernisation in Victoria to provide a total of 425 GL in water savings. To date, the federal government has bought about 250 GL in northern Victoria for the environment, costing around $550 million. So water saved from modernisation costs around $4,700 per million litres, twice as much as the market price of water.
There is no doubt that the balance of investment is out of whack, especially as successive state governments have refused to invest in water buy-back. Investing directly in water buy-back could return much more water to our rivers. The Productivity Commission agrees, finding that water buyback is both more cost effective and more equitable than modernisation.
The second concern is that the area under irrigation will have to be reduced in a drier future. It is widely accepted that some parts of the irrigation system are no longer viable and many other parts will become less and less viable under climate change. Modernisation in these areas is not a sound investment. The Campaspe system is a good example where farmers have decided to sell their water entitlement and close down the irrigation area because there simply was not enough water anymore to rely on for growing crops.
Neither the state nor the federal government have been clear on how much the irrigation area should be reduced.
Decisions on which areas remain in irrigation should be based on land capability and climate change projections of water availability. Where irrigation is viable, irrigation systems and farms should be modernised with the aim to achieve a ‘factor 4’ increase in productivity – twice the value of production for half the volume of water. Where irrigation is no longer viable, water should be bought for the environment and affected farmers and communities should be given assistance to transition to other forms of income such as dryland farming, carbon sequestration and ecosystem services.
1. a public plan on where it will boost irrigation efficiency and where it will retire non-viable irrigated land; and
2. a water buy-back fund to purchase water for our rivers and wetlands, in particularly focusing on securing water for our newly created Red Gum parks