How much water does the Murray actually need?

THE debate about how much Murray-Darling water to transfer from human activity to the environment tends to overlook a very important point: how can you prove the environment is receiving enough?

Other than in a flood, many of those who believe the environment has priority will never accept it receives enough water. This is common in the native forestry debate too, where concessions simply become the starting point for further claims by environmentalists.

It is very obvious from the way the bar has been raised over the years. As Jennifer Marohasy has pointed out, in June 2003 Peter Cullen from the Wentworth Group of Concerned Scientists mentioned returning 1500 gigalitres to the Murray Darling river system, and indicated that volume was scientifically derived.

In 2004 former Labor leader Mark Latham promised to add 450 gigalitres of environmental flows in his first term and an extra 1500 within ten years. Greens leader Senator Bob Brown said he would return 1500 gigalitres within five years.

Now, the Wentworth Group claims at least 4000 gigalitres must be returned to the system while the Greens are claiming a minimum of 4000 gigalitres to ensure the river’s survival, and 7600 gigalitres if it is to be healthy.

Pressure on the government to increase the 2750 gigalitres set out in the MDBA’s Proposed Basin Plan is based on assertions that the environment is facing a crisis. Yet what constitutes a healthy environment, or even one that is sustainable or not in crisis, is never explained. The drought was often said to be an environmental crisis, yet it is just as natural as the subsequent floods.

As most people in business know, the way to resolve imprecision is to have specific, measurable objectives, to be achieved within a designated time period. Success or failure is then measured against whether the objectives have been achieved.

The Proposed Basin Plan includes targets for various measures of water quality including pH, turbidity, nitrogen, phosphorus, salinity, temperature and pesticides. The implication is that if these targets are met, the environment will be healthy.

These are not the only objectives being promoted though. The Premier of South Australia, Jay Weatherill, wants 4000 gigalitres more freshwater each year for South Australia as guaranteed supply, requiring the storage of a lot more water in the environmentally protected Lower Lakes.

In the MDBA discussion document ‘About the draft Basin Plan’ it is asserted that the Plan’s proposal will achieve “the objectives of keeping the Murray flowing to the sea nine years out of 10, to flush salt from the system and water important sites in the Basin.”

Much more consideration should be given to which objectives the Plan should aim to achieve. If they include water quality then the nature, frequency and location of measurements in the various catchment areas are key concerns. Monitoring salinity will at least resolve the question of whether the river actually needs flushing.

On keeping the Murray mouth open 9 years out of 10, there should be debate about whether this is an indicator of environmental health, why there are plenty of healthy rivers that only flow to the sea in wet years, and how this reconciles with the fact that south-east Australia tends to have 7 year cycles in which two are wet, two are dry and three are average.

If improving Adelaide’s water security is an objective (as an outcome of benefiting the Lower Lakes, because the Water Act gives the environment priority), debate should focus on the implications for water users and the environment higher up the system.

Given proper, measurable objectives, the amount of water reserved for the environment becomes a tool to achieve them, not an end in itself. If it turns out that salinity is not a problem, water for flushing will not be necessary. If measurements indicate water quality is well above the targets, environmental flows can be reduced. And if the objectives are not achieved and it is apparent the environment needs more water, there will be greater public support for measures to provide it.

The Water Act is fundamentally flawed and ought to be replaced with a water trading system that puts a value on all water, including water for the environment. But while we are stuck with it, there should at least be acceptable, specific, measurable objectives regarding the environment. Anything less will invite a perpetual crisis.

Agribuzz with David LeyonhjelmCommentary, news and analysis with agribusiness consultant David Leyonhjelm. Email David at


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