Murray River

THERE are a lot of comments in the thread following my blog post ‘Healthy Country Means Less Water for South Australia’. In that thread Peter R. Smith OAM has claimed that if it weren’t for the barrages Lake Alexandrina, a terminal coastal lake at the bottom of the Murray Darling catchment, would become hyper-saline. In the same thread Sean Murphy has replied, but Lake Alexandrina was once tidal, so how could it become hyper-saline?

It could become hyper-saline if the Murray’s sea mouth closed over completely, something that engineers warned in 1903 could happen if the barrages were built stopping inflows from the Southern Ocean – stopping the tide.

Soon after Europeans started farming on the shores of Lake Alexandrina they began devising plans to preventing it from becoming salty. The first such plan was presented to the South Australian parliament in 1890. Prepared by the Engineer in Chief Alex B. Moncrieff it proposed the building of a lock on the Goolwa channel and barrages across the other channels to prevent seawater from entering the lake.

Federation, and the 1895-1902 drought, focused the attention of the communities along the River Murray on the need for cooperation if they were to develop the waters of the River Murray. In 1902 the Corowa Water Conservation Conference led to an Interstate Royal Commission with the purposes of “To inquire and report on the conservation and distribution of the Murray and its tributaries for the purpose of irrigation, navigation and water supply.” It was another twelve years before the River Murray Waters Agreement 1915 was ratified which created water sharing principles for New South Wales, Victoria and South Australia including an annual water entitlement for South Australia to be met in equal share by Victoria and New South Wales, and the development of a program of major works including the construction of dams and weirs which the three states and the Commonwealth where to jointly fund.

In the meantime a more substantial plan was developed to prevent Lake Alexandrina becoming salty, as it had during the federation drought. The plan was presented to government in 1903 as a joint report by T.W. Keele the Principal Engineer of Harbors and Rivers of New South Wales, W. Davidson the Inspector-General of Public Works of Victoria and Mr Moncrieff who was still the Engineer in Chief in South Australia.

The report, dubbed, the “Report by Experts” begins with reference to why the best option for securing “the impounding of the fresh water” should involve the blocking of several channels from the lake that converge on the Murray’s sea mouth rather than placing a barrage across the actual sea mouth of the river. The report also explains why the barrages should be placed such that they exclude the Coorong from the Alexandrina lake system because the Coorong represented “an evaporating area of 90 square miles additional to that of the lakes”.

The report details and quantifies the tidal influence through each of the channels relative to a tidal gauge at Milang. The opening between Mundoo and Hindmarsh Islands is referred to as the most direct outlet from the lakes to the sea and with a tide that rises considerably higher than the tide through the Goolwa channel. Different barrage structure were proposed for each of the channels with a permanent earthen wall pithed with stone across Boundary Creek, while for the Goolwa it was proposed a sheet-pile structure be built with a lock large enough for river steamers.

The Report by Experts includes two important warning: that after construction of the barrages the Murray’s mouth would be expected to close over completely; and before erecting the barrages a more regular supply of fresh water from the river would first need to be secured or the lakes would dry-up during periods of drought. These important caveats have been subsequently ignored by state and commonwealth governments and are never referenced in the very many reports published with increasing regularity by the Murray Darling Basin Authority.

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Report by experts. The Murray Barrages. August 20, 1903. The Advertiser p. 8 http://nla.gov.au/nla.news-article4987833

DAVID Wroe from The Sydney Morning Herald has written a well balanced article on the waste of money in buying Toorale (pronounced Too-rally) Station at Bourke: http://www.smh.com.au/environment/station-buyout-a-waste-of-money-20111223-1p8ln.html.

I attempted to leverage this with a letter to the Editor which failed to make the final cut:

Congratulations to the SMH (Station buyout a waste of money- 23rd December) for “outing” the Commonwealth and former NSW State Government for the total waste of $23.75m in purchasing Toorale Station. Not only was this a waste of taxpayer’s funds for negligible environmental benefit, it also took out of production the hard hit Bourke community’s most productive enterprise. How downstream grazier Justin Mc Clure can argue that a 0.01% increase in flow can generate downstream environmental benefits is a real mystery.

The episode has wider ramifications in terms of the Draft Murray Darling Basin Plan. The Commonwealth Water Act 2007 and the approach of the Murray Darling Basin Authority is deeply flawed and the Toorale outcomes represent a good example of the likely consequences-negligible environmental benefit, but significant negative economic consequences. When flows are low, license conditions prevent extractions and diversions, when flows are significant the impacts of extractions and diversions are minimal. Dorothea Mackellar was absolutely right in describing inland Australia as a land of “droughts and flooding rains”, she could have added and “not much in the middle.

In using absolute numbers as the MDBA has done, to prescribe acceptable extractions/diversions limits without gearing these to actual flows (availability) is really nonsense. To argue that these numbers are “averages” doesn’t help, given the enormous spreads around the averages. Our current water bureaucrats could do worse than studying how the existing control system operates. It works rather well.

J.D.O.(David) Boyd
St Ives NSW 2075
(Former Chairman and CEO of Clyde Agriculture, the previous owner of Toorale Station)

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And sign the petition here please http://listentous.org.au/

IT is assumed in the draft Murray Darling Basin Plan that the more water in the Murray River and in particular the more water moving down the river to South Australia, the healthier the environment. But what’s the philosophical basis for such an assumption?

As I wrote in my column for The Land newspaper this week:

If the current water reform process is truly about giving back to the environment, then we should be thinking back to a period before rivers and creeks became constricted by sheets of water running off compacted soils, before swamps were diverted, before river de-snagging and before the blasting of rock bars for paddle steamers.

As historian Bill Gammage notes in The Biggest Estate on Earth: How Aborigines Made Australia, back in the dreamtime shallow streams and overflows flushed more of Australia, filling billabongs, swamps and holes, and recharging springs and soaks.

That was a time when the health of a landscape was measured less by how much water was in a river, and more by how many kangaroos it could support.

In 1901 James Cotton, a Cobar pioneer, wrote that before the district was stocked with sheep and cattle it was covered with a heavy growth of natural grasses and that the ground was soft, spongy and very absorbent.

Overstocking was a problem throughout the Murray Darling Basin particularly during the late 1800s resulting in significant land and water degradation. Overstocking transformed soils in many districts from soft and spongy to hard clay that, instead of absorbing water, caused the rain to run off in sheets as fast as it fell – to again paraphrase Mr Cotton.

In the past one hundred years there has been a gradual improvement in land management. Stocking rates have fallen, some native grasses are returning and there has been a move to minimum tillage conservation farming practices. This has resulted in a general improvement in soil structure.

The ground may not be as soft, spongy and very absorbent as it once was, but there is no doubt that when the rain now falls on the Murray Darling, much less water runs off into adjacent rivers and streams than it did one hundred years ago. This must have implications for the amount of water flowing to South Australia.

Indeed a truly healthier Murray Darling Basin would mean less water for South Australia.

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My entire column can be read on page 9 of The Land – in newsagents now.

Bill Gammage, The Biggest Estate on Earth: How Aborigines Made Australia. Allen & Unwin, 2011. I got my copy from Dymock’s in Sydney for $49.99; and bought another as a Christmas present.