Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Murray River

South Australian Water Minister’s Foolish Statements About Murray River and Ngarrindjeri Culture

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YESTERDAY the South Australian government yet again displayed its contempt for science and history by claiming yet again that Lake Alexandria is, and always has been, a freshwater lake.[1]

I’m hopeful that the local tabloid, the Adelaide Advertiser, will publish my reply. So far this News Ltd publication has refused to let me respond to various articles about me.

My Letter to The Editor:

Paul Caica, South Australian Minister for Water and the River Murray, claims that in wishing to restoring the Murray River estuary, I show disrespect for scientific work and the culture of the region’s traditional owners, the Ngarrindjeri (Lakes flood plan defiles the existing evidence, Adelaide Advertiser, March 31, 2009).

In fact, all the science published in peer-reviewed journals is on my side. Minister Caica’s claim is consistent with the Book of Genesis in the Bible inferring the estuary came ready-formed with a sand barrier and central lagoon. But such an interpretation denies geological and environmental reality. The scientific literature clearly shows that Lake Alexandrina has a marine origin that dates back to a period of late Pleistocene and early Holocene sea level rise. Since this time the coastal sand barrier and related landward estuarine environments have evolved and changed naturally, including manifold changes in salinity.

The Murray Mouth barrages were built to stop saltwater intrusions that were a problem from the time of European settlement. Indeed, long before the development of upstream irrigation, the Southern Ocean would push in each autumn and for longer periods during drought.

The seawater poured in through the Murray’s mouth and sometimes worked its way across the lake and then into the River Murray proper as far north as Mannum. This is recorded in the patangi – a song category of the Ngarrindjeri. In one of these stories, the River Murray drags trees along as sea water flows upstream as far as Mypolonga. The river water was too salty to drink and the Ngarrindjeri were forced to dig wells about two feet deep to get drinkable water.

Minister Caica really should read more and/or consult more widely to avoid making foolish statements.

Jennifer Marohasy
Biologist, Noosa, Queensland

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Honest Politician Needed to Champion Removal of Murray Mouth Barrages

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For years now I’ve been writing about the barrages, really sea dykes, that block inflows from the Southern Ocean making the vast shallow coastal lagoons at the end of the Murray River completely dependent on Murray River inflows. Without the dykes the sea would push in each autumn and for longer periods during drought.[1]

Somewhat disappointingly for me there is not one state or federal politician who will take up this issue of the Lower Lakes and in particular how the current management of Lake Alexandrina as an artificial freshwater oasis is unsustainable.

That was my message to Labor, Liberal, National and Greens Senators and MPs representing voters from across the Murray Darling when I visited Canberra in July last year. My trip was funded by Johnny Kahlbetzer from Twynam Agricultural Group. My message was that:

1. The health of a river system is more than the quantity of water flowing downstream;
2. Current management of Lake Alexandrina as an artificial freshwater oasis is unsustainable; and
3. Restoring the Murray River’s estuary must be a priority in any Murray Darling Basin Plan.

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Time to Rethink Basic Assumptions about the Murray and the Planned Water Reform

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TONIGHT the Australian Broadcasting Corporation’s Media Watch program put together a garbled defence of the consensus position on water reform and the Lower Murray, a position based on ‘junk science’.

The program omitted to declare that the federal government, the same government that funds Media Watch, has committed $10 billion for the implementation of the water reform plan.

My objections to the A$10 bilion plan are explained in part in my recent report ‘Plugging the Murray’s Mouth: The Interrupted Evolution of a Barrier Estuary’. Extracts from this report follow:

FOR thousands of years before the European settlement of Australia, when there was good snowmelt in the Australian Alps, the Murray River would tumble down from the mountains, then spread west over the vast black soils of the Riverina, wind its way south through the limestone gorges of the Riverland, before flooding into Lake Alexandrina. Lake Alexandrina is still a vast body of water covering an area of 570 square kilometres; so vast that looking back across the lake from Point Sturt, shorelines recede into the distance and it’s impossible to see Pomanda Point near where the river enters the lake.

While the lake is vast, its outlet to the sea is a narrow and shallow channel between the sand dunes of Encounter Bay – an outlet that sometimes closes over.

In April 1802 British explorer Matthew Flinders, while circumnavigating Australia, described the shoreline as low and sandy topped with hummocks of almost bare sand. There was no river mouth on his map. Historians have written that this acclaimed navigator and cartographer “missed” the Murray’s mouth. It is much more likely that the inlet had closed-over.

Twenty-eight years later, in February 1830, another famous British explorer, Charles Sturt, visited the region but from the inland, travelling-down the Murray in a whaleboat. Captain Sturt described the place where the river enters the lake, which is about 60 kilometres from the Southern Ocean, as the end of the river. He wrote in his journal that:

“We had, at length, arrived at the termination of the Murray. Immediately below me was a beautiful lake, which appeared to be a fitting reservoir for the noble stream that had led us to it; and which was now ruffled by the breeze that swept over it.”

On the third day, Captain Sturt attempted to manoeuvre his whaleboat from the lake to the Southern Ocean but was blocked by sandbars.

“Shoals again closed in upon us on every side. We dragged the boat over several, and at last got amongst quicksands.”

It was not until the fourth day that Sturt conceded that it would be impossible for his men to drag the whaleboat any further over the sand bars and sand flats. So, again in February 1830 the Murray’s sea mouth was closed-over.

When Captain Sturt’s diary was later published it included comment that:

“Australian rivers fall rapidly from the mountains in which they originate into a level and extremely depressed country; having weak and inconsiderable sources, and being almost wholly unaided by tributaries of any kind; they naturally fail before they reach the coast, and exhaust themselves in marshes or lakes; or reach it so weakened as to be unable to preserve clear or navigable mouths, or to remove the sand banks that the tide throws up before them.”

In fact, the Murray River often ran strong in spring and summer, but by autumn had slowed and then a south westerly wind would pick up and the sea would pour in.

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Media Watch Under Scrutiny

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MEDIA Watch contacted me on Friday with a barrage of questions concerning my work on the need to restore the Murray River’s estuary. Their line of questioning suggested that I was misleading the Australian public on the important issue of water reform in the Murray Darling. Indeed, the implication was that I am but a stooge for vested interests.

It appears Media Watch is contemplating asserting or implying that my professional judgement and integrity as a scientist has been influenced or corrupted by personal financial gain. Accordingly, I have sought legal advice on the matter, and include this in my full response that can be downloaded here:

https://jennifermarohasy.com.dev.internet-thinking.com.au/wp-content/uploads/2012/03/JenniferMarohasy_ReplytoMediaWatch_Amended12March.pdf

My responses to their specific questions also follows:

Media Watch: Do you accept that the vast majority of recognised experts on the natural history and hydrology of the Lower Lakes disagree with your conclusion that they were estuarine immediately prior to the erection of the cialis Murray Mouth barrages, or at any time in the past 2000 years?

Jennifer Marohasy: No. The relevant scientific literature, as published in peer-reviewed journals by recognised experts, indicates that the Lower Lakes were estuarine prior to the erection of the Murray Mouth barrages.

The following quote from a scientific paper published in the journal Marine Geology by Professors R.P. Bourman, A.P. Belperio, C.V. Murray-Wallace and N. Harvey, citing E. Barnett, seems to sum up the conclusion of these recognised experts:

“Originally a vibrant, highly productive estuarine ecosystem of 75,000 ha, characterised by mixing of brackish and fresh water with highly variable flows, barrage construction has transformed the lakes into freshwater bodies with permanently raised water levels; freshwater discharge has been reduced by 75% and the tidal prism by 90% (Bourman and Barnett, 1995; Harvey, 1996).”

Professor John Cann and co-workers have studied fossil foraminifera – tiny protozoa with shells of calcium carbonate preserved in the sediments of the Lower Lakes – concluding that the changes in the foraminiferal assemblages over the most recent 2,000 years indicate a general trend of increasing marine influence, up until the construction of the barrages that now block the natural ebb and flow between the Lower Lakes and Southern Ocean.

Professor Peter Gell writing in the recently published The Sage Handbook of Environmental Change has commented that the natural state of the Lower Lakes was tidal, that the lakes have been incorrectly listed as freshwater in the International Ramsar Convention, and that until their natural estuarine character is recognised it will be difficult to reverse the long-term decline in their ecological health.

Geoscience Australia classifies the Lower Lakes as part of a wave dominated barrier estuary with positive annual hydrodynamics.

UPDATE: I have been informed by Media Watch that they will NOT be running their intended program tonight (“This item will not be on this week’s show”). It would appear that the possibility of a defamation action coupled with a solid explanation of the science and history of the Lower Lakes has caused Media Watch to change their program. I would like to particularly thank those people who sent emails to Media Watch this morning.

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Minister Caica Ignorant of History of Lake Alexandrina

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Following the release of my recent technical report, Plugging the Murray’s Mouth: The Interrupted Evolution of a Barrier Estuary [1], the South Australian water minister, Paul Caica, made public comment that Lake Alexandrina has been a “predominately freshwater environment for the last 7,000 years”. The Minister also indicated that my claim that Lake Alexandrina was once part of an estuary is “myth and not supported by science.”[2]

In fact the relevant scientific literature, as published in peer-reviewed journals, indicates that the Lower Lakes were estuarine prior to the erection of the viagra sea dykes, known locally as barrages. But it is also revealing to simply consider the history of the region. The first map of Lake Alexandrina, drawn by John Arrowsmith in 1838 based on reports of water quality from the famous British explorer Charles Sturt, shows the waters of Lake Alexandrina to transition from salt to brackish to fresh.


[This map has been copied from a zoom here http://nla.gov.au/nla.map-rm2633]

It appears that the South Australian government is also ignorant of the history of the lake with comment in important planning documents that: “The Lower Lakes have been predominantly freshwater for the last 7,000 years and that seawater ingressions, when they did occur, did not extend north of Point Sturt.”[3]

Point Sturt is clearly marked on the 1838 map. The map clearly shows that seawater ingressions extended into the main body of the lake turning the water brackish.

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[1] The report can be downloaded here: https://jennifermarohasy.com.dev.internet-thinking.com.au/publications/

[2] Water must mix in the Lower Lakes, says new Murray-Darling report. Adelaide Advertiser, February 24, 2012. Available online at http://www.adelaidenow.com.au/news/south-australia/water-must-mix-in-the-lower-lakes-says-new-murray-darling-report/story-e6frea83-1226281052851

[3] Securing the Future: A Long-term plan for the Coorong, Lower Lakes and Murray Mouth, June 2010, Government of South Australia. Available online as a 13mb pdf.

 

About the Murray River’s Estuary: Full Text of My Address to the Sydney Institute

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AT the very bottom of Australia’s Murray-Darling Basin is a vast coastal lagoon that was once connected to the Southern Ocean. The region was home for the Ngarrindjeri, who wore possum skin coats and loved to tell stories. One of their storiesii is about greed and the environment and also the consequences of telling lies.

Two men set off in their bark canoe for the Ngiakkung, a shallow, reed-filled corner of the lagoon their tribe favoured for fishing. That day thukeri, or bream, were so plentiful that the fish all but hopped into the canoe. Having acquired a substantial haul, one said, “Hey brother, we have plenty of thukeri. Let’s paddle to the shore before we sink.” But his friend, for whom plenty was never enough, wanted to keep on fishing. The fish piled up even higher in the canoe, which sank even lower.

Eventually, they paddled towards the shore, where a stranger stood. “Hey brothers, I’m hungry,” he called out, “Have you got any fish to share?”

The rapacious one replied, “No, we haven’t. Just enough to feed our families.”

As the stranger turned to walk away, the men started laughing behind their hands. The stranger heard them and said, “You have plenty of fish, but because you are greedy and don’t want to share, you will never enjoy the thukeri again.” When the men reached the bank, they found the fish they had caught were thin and full of sharp bones.

They told their families what had happened. The old people said that the stranger was the Great Spirit Ngurunderi. From then on, for all time, the Ngarrindjeri people would be punished. Today, whenever Ngarrindjeri catch a bony bream, they are reminded of long ago, when Ngurunderi taught them a lesson.

During the recent drought, the waters of Ngiakkung, a place now called Loveday Bay, dried up. No one could ever remember the lagoon, now called Lake Alexandrina, drying up before.

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