PASS the SALT please
Jul 12, 2001 Write an essay on this topic.
The Bottom Line Most of Australia's inland lakes hold water infrequently
Salt, Salt and more salt. That describes the vast and numerous salt lakes in the South Australian Outback. And the biggest salt lake of them all is Lake Eyre.
Good old Lake Eyre is not your ordinary lake - it covers 700 000 square miles, which is 15% of the Australian continent and its in some of Australia's, and the world's most arid country. The Lake Eyre Basin is the world's largest internal drainage system.
Despite that the lake is dry most of the time. A hard crust of salt forms and when this occurs it has proved the ideal location for world record land speed attempts. But a word of warning for those travelling to Lake Eyre by vehicle.
Sometimes the salt looks dry and hard when actually it isn't. Many vehicles have met their peril when just below the surface the salt is a giant mush. It is best to ask the locals the condition of the crust, rather than race off into the vast whiteness and sink without warning halfway to China.
The Diamantina River and Cooper Creek that feed the lake spasmodically and unreliably flow through semi-arid and arid regions of Australia, and strangely some of their most significant wetlands coincide with some of the most arid areas of the continent. The rivers receive their waters mainly from summer tropical rainfall falling a thousand miles to the north.
These two rivers are amongst the few remaining major rivers with virtually untouched natural flows in the world. Floods sustaining vast wetlands, support rangeland grazing and are the trigger for breeding activity in many native species. During dry periods, the wetlands of the Lake Eyre Basin are vital drought refuges for wildlife.
Although the water is far to salty to drink, The Lake Eyre Basin is one of South Australia's five key water resources. They are valued for the "conservation of wetlands and aquatic ecosystems, in particular the Coongie Lakes wetlands which are classified as Wetlands of International Importance under the Ramsar Convention".
This fact is clearly demonstrated when you appreciate that during the last 'big wet' in 1990/91, there were over 400 000 waterbirds recorded on Lake Eyre North alone, with many hundreds of thousands on other wetlands in the Lake Eyre Basin. At that time the number of waterbirds in Lake Eyre at the mouth of Cooper Creek were similar to densities of waterbirds in the well-known Kakadu region in the Northern Territory.
Most of Australia's inland lakes hold water infrequently. The lake filled completely in 1950 & 1974--but has held good quantities of water in 1956, 1976, 1989, 1997 & 2000. Indications are the 2001 will also be a good year for the lake. In 1974 the lake filled to a depth of 18 feet-& held some 20 cubic miles of water. One point in Belt Bay is acknowledged as being the lowest point in Australia--60 feet below sea level. The salt crust can be up to 1.5 feet thick with a total weight estimated to be around 400 million tons. Not surprisingly the salinity level far exceeds that of sea water, while the sea is about 600 miles to the south.
The year 2000 has seen phenomenal interest in the Lake. Visitors from all over Australia & around the world have flocked to it's shores, paddled in it, sailed on it, or flown over it. It has been a bit of a shock to some Outback towns, especially the likes of William Creek, the nearest town to the lake and the countries smallest town with its resident population of ten. The William Creek hotel is not exactly one of the Hyatt chain, so whole "tent cities" have sprung up to accommodate the sightseers.
Hundreds of vehicles a day have ventured out on the dusty tracks to reach this amazing place - quite a surprise to roads that normally only carry one or two vehicles per day and are graded once a year whether they need it or not! The William Creek airport became quite busy, but at least its not a long way out of town - in fact the main street is the runway! Actually it has to be the worlds best airport - where else does your plane taxi right up to the front door of your hotel? The only surprising thing is that this commonsense idea hasn't been copied worldwide as it would cut travelling times enormously in the major cities.
In this arid country water means life-- & when it comes life abounds. Around you, everywhere, wildflowers bloom, desert creatures breed at an amazing rate, and birds flock in as if attracted by a magnet. Pelicans, gulls, stilts & many more come to nest, the fledglings growing fast on the abundant nutrition of the lake. The way the fish, crabs and so on that burst into life is incredible and the subject of much study - as the water evaporates they dig in deep and can somehow hibernate for decades, especially those dug in around the outer edges.
Then everything changes very rapidly, just as quickly as the inflow slows. The water evaporates at a huge rate and the Lake dries in no time leaving the various creatures that can't return to the salt and hibernate only two options - either leave or stay and die. Their decomposing bodies, in the hundreds of thousands, returning nutrients to the earth from which they came.
It is nature at it's rawest.
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