The Black Swan of the Murray-Darling Basin Plan

1 April 2016
The Black Swan of the Murray-Darling Basin Plan - Featured image

A ‘black swan event’ refers to the unprecedented— something that changes how we previously perceived reality. The Murray-Darling Basin is a place replete with black swans (both figuratively and literally), particularly the Lower Lakes, Coorong and the Murray Mouth.

Over 4,000 black swans were counted in a bird census of the Lower Lakes in January 2011, and there are oft en over 1,000 of them in the vicinity of the longthin Coorong. Historically, black swans have nested amongst the 100 kilometer-long system of sand dunes that separate the Coorong from the deafening surf of Encounter Bay.

It is this region, more than any other, which has driven water reform across Australia. More specifically, the concept that the Murray Mouth (which is a narrow outlet between sand dunes just to the west of the Coorong), closes over because upstream irrigators take too much water. Indeed, the blocked mouth of the Murray has become a symbol of greed and unsustainability, spurring water reform. To quote from a recent ABC online article:

An open mouth is a representation of a healthy river. If you don’t have a healthy system at the bottom end, you certainly don’t at the top end.

A key policy document from the Australian Conservation Foundation also makes the point, stating:

The Basin Plan must provide adequate end-of‐system fl ow to keep the mouth of the Murray open without dredging.

The Murray-Darling Basin Plan is a requirement of the Water Act 2007, giving eff ect to international agreements, and ostensibly establishing a long-term adaptive management framework for water resource planning.

What is absent from this planning, however, is any reference to the sea dyke, known locally as barrages, built across the bottom of the Lower Lakes. There are six barrages stretching for a total of 7.6 kilometers that have restricted water flow from the Lower Lakes to the Murray Mouth since February 5, 1940. The stop logs are opened periodically to release freshwater, but typically closed in autumn when south-westerly winds, combined with high tides, once pushed seawater in through the mouth.

The Goolwa barrage is not the longest of the barrages, but it is impressive at 632 metres long with 122 concrete piers each about 6 metres tall. In between the piers are the manually operated concrete stop-logs.

An assumption in the Basin Plan is that river flow alone, after it crosses the vast and shallow Lake Alexandrina, and subject to the stop-logs in the barrages being open, will flush the Murray River’s sea mouth. It is 76 kilometers by Kayak from Wellington to Goolwa.


Before the barrages, the Yaraldi group of the Narrinyeri people lived on the eastern shores of Lake Alexandrina, and around Lake Albert and along the Coorong. Albert Karloan was one of the last three Yaraldi youth to undergo full initiation rites in the Lower Murray Region. His knowledge of the Dreamtime stories of the region reveal a lot about the early geography of the area, and were recorded by anthropologist Ron Berndt in 1939.

One of these stories concerns the Murray Mouth, in particular Karloan tells how back in the Dreamtime, the great hunter Ngurunderi walked across the Murray Mouth in pursuit of his two runaway wives. Of course, back in the Dreamtime there were no irrigators upstream to take the water. So perhaps the Murray River’s sea mouth had closed over naturally.

In his book Poor Man River: Memoirs from the River Murray Estuary, Mulloway fisherman Alistair Wood writes about how before the barrages the Murray River would:

Flog down from September until maybe Christmas, filling the lagoon, then out the mouth.

By Christmas, flow had usually slowed and water levels dropped right down. After this, when the south-westerly wind picked up, the sea would ‘pour in through the mouth and work its way across the lake’.

Perhaps when Ngurunderi visited Tapawal, it was just that time of year when water levels had dropped right down, and the mouth had closed over.


The many reports from the Murray- Darling Basin Authority that informed the Basin Plan, claim the Murray Mouth closed over for the first time in 1981. But perhaps this is incorrect, as also evidenced by the first maps of the coastline.

There is no river mouth on Matthew Flinders’ map of the shoreline of Encounter Bay described on 8th April 1802 as ‘low and sandy topped with hummocks of almost bare sand’.

The French were the first to send an expedition with the specific objective of completing the exploration of the coastline of Australia. Nicolas Baudin departed Le Havre on 19 October 1800. The British Admiralty, at war with France, was suspicious of Baudin’s expedition and hastily commissioned Matthew Flinders to the same task. He set sail nine months later on 18 July 1801; it was inevitable that their ships would meet. This happened on 8th April 1802, about six nautical miles south-south-east of the place the Yaraldi knew as Tapawal. To commemorate their meeting, Flinders named the bay Encounter Bay.

Flinders had been sailing east and had charted the Spencer Gulf and the Gulf St Vincent on which Adelaide is now situated. While Baudin was sailing west charting the coast from the ‘Promontoire de Wilson’ including the inlet of Port Phillip, on which the city of Melbourne is now situated. Baudin’s cartographer, however, like Flinders, missed the Murray’s mouth.

Three decades later, on 12th February 1830, British explorer Charles Sturt walked east along the shores of Encounter Bay, and across Tapawal or, the Murray Mouth.

Sturt entered Encounter Bay on foot over a sand hummock in search of an outlet for his nine-meter long whale boat—a boat his crew had variously sailed and rowed down the Murray River, and then across Lake Alexandrina.

The map, drawn by well-known cartographer of that time John Arrowsmith, after this expedition describes the waters of Lake Alexandrina as ‘fresh’ towards Wellington, most of the lake as ‘water brackish’, transitioning to ‘salt’ well upstream of Goolwa.

In Sturt’s diary the Murray Mouth is described as a ‘low beach’ covered in water at high tide. The Arrowsmith map colours the Goolwa channel dark blue, and the surf of Encounter Bay as light blue—with a strip of sand between the two. Indeed, from scrutiny of Sturt’s diary, and the associated Arrowsmith map, it would seem that the Murray Mouth had closed over again back in February 1830.

The story repeated in official planning documents that underpin the Basin Plan, is that the Murray Mouth closed over for the first time in 1981. This often repeated claim contradicts not only the Yaraldi Dreamtime story, but also the very first official maps of the region, and the stories from the Mulloway fishermen.

In secular democracies like Australia, public policy should be based on evidence. When we see black swans we should call them as such. But in a region replete with black swans, the modern bureaucracy backed by government-funded scientists continues to deny reality. This idea that the Murray River could, and should, run strong and fresh all the way to the Southern Ocean is based on nothing more than a romantic impression of how the Australian environment could be.

In 1914 and 1915, before any significant water infrastructure development, the Murray River ran dry, but the Lower Lakes were full of water. Dolphins were sighted upstream of Wellington, with sea water penetrating to Mannum.

During the recent millennium drought—despite exceptionally low rainfall and snowfall—the river proper kept flowing because of releases from the Hume and Dartmouth reservoirs.

But there was simply not enough water to keep the vast and shallow Lower Lakes full of freshwater. And there was certainly not enough water to flush the Murray’s sea mouth.

The waters of the Lake Alexandrina did however start to dry up. This was reported as a national tragedy and all the fault of up-stream irrigators—never mind that by simply opening the barrages the entire lake system could have been flooded with sea water at no cost to the Australian tax payer.

It is as though water resource managers are more committed to there being a problem in the Murray-Darling, than finding real and sustainable solutions which could reside at least in part with the restoration of the estuary—not keeping the Murray River’s sea mouth open.

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