How much water does the Murray actually need?

06 Feb, 2012 09:00 AM

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.

David Leyonhjelm is an agribusiness consultant with Baron Strategic Services.

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Ian Mott
6/02/2012 11:12:30 AM

Yep, 14 million megalitres of Murray flow in 2010 only reduced salinity in the Coorong's south Lagoon from five times sea water to 2.5 times that of sea water. This proves that only 70,000ML of fresh water actually made it into the 140,000ML lagoon. Salinity levels are already going back up again and you can bet your last dollar that the SA government and witless group of WWF funded scientists will then use it as justification for wasting even more water.
6/02/2012 1:29:04 PM

Adelaide is a poorly located city in a very low rainfall area, it should be paying a lot more for fresh water which travels thousands of miles to get to it, and it should have a population cap of 500,000 people put on it.
6/02/2012 3:58:30 PM

And while we are at it, irrigation districts such as those found in areas like Hay, who continue to irrigate from water delivery systems not disimilar from those instigated by the Chaffey Brothers well over 100 years ago, should be shut down. The enormous amount of water saved from thousands of kilometers of earthen channel being taken out of commission could then go to those who can demonstrate efficient use. Sound absurd Pete? Not nearly as absurd as your suggestion.
7/02/2012 6:16:12 AM

Well done David, take the emotion out and add sensible debate; the Basin Plan does provide for adaptive management as the objectives are monitored with science and measurements. The strategy of infrastructure improvements is another extension of the Basin Plan and does not get enough emphasis, but can be clearly seen in the Hay Private Irrigators receiving funding and closing off hundreds of Km's of open channels for a piped scheme; the Wah Wah scheme is headed the same way - catch up fridg, and stop peddalling the old paradigm
On The River
7/02/2012 8:21:48 AM

Great article that goes to the heart of the problem. The MDBA have failed to be able to justify the need for so much more water because they have failed to clearly benchmark where we are and what they hope to change. How can you monitor success if you don't know what your starting point is.
7/02/2012 8:50:49 AM

@ maccahay It is too late for fridgimus my diagnosis is terminal id ten T syndrome. Shutting down complete systems really? You can't be serious! Listen to Motty. He has an answer that will save multiples of that 'lost' in channels. Add to that the vastly improved benefits to the Murray mouth and Coorong and there is little need to do much else. Fund it by sacking the entire MDBA and save taxpayers dollars by the $billions.
7/02/2012 9:03:30 AM

It looks like the old green/ conservationist/ communist dogma. When you look like getting what you want, then you try to have it increased. A 1500 gig ask becomes 4000. One wonders what they are on about, now that there is another massive flood moving down the Darling system from Qld. They are still trying to gain some mileage from the 10 year drought that has long broken.
7/02/2012 9:18:55 AM

Well its great that you are catching up at last, even if it is tax payer $$ that are being used to fund the improvements. Better late than never. The state that you all love to bag did this decades ago, largely funded by the growers themselves and the SA government. Despite that investment we are being given no credit for that in the basin plan and stand to lose the most, despite our long term commitment to the welfare of the river.
7/02/2012 9:25:00 AM

I do not disagree that the plan to pipe sea water into would improve the health of the Coorong, but that will do nothing to help the hundreds of wetlands from the barrages to the Darling river junction and is not the silver bullet you are claiming it to be. A return to a flooding cycle of 1 in every 5-7 years instead of the 1 in 20 that occurs now is what is needed to keep the river in a working condition in the long term. Historically the frequency was 1 in 3 years.
7/02/2012 9:50:56 AM

Climate change is now being debunked from many quarters and the scientists who have produced those theories scream when their claims are questioned. Take out the ten year drought anomoly (which will not occur for another hundred years) then look at the data again. Like farm land, the rivers will take time to recover and the floods have already put that recovery in place. Just look at the billions of new trees starting to grow where the drought devestated many wetlands. Nature is about death and renewal just like human life, except we have the cognitive power to make nature more productive
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