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.
[Read more…] about Time to Rethink Basic Assumptions about the Murray and the Planned Water Reform
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.