Lake Eyre is a huge inland lake in central Australia covering almost 10,000 square kilometres making it the fifth largest terminal lake in the world. At 15 metres below sea level Lake Eyre is the lowest point on the Australian continent. The lake itself is split into two sections, North and South. The entire catchment area for Lake Eyre is over 1 million square kilometres, much of which is semi-arid desert.
Normally Lake Eyre is a dry saltpan with a crust that is up to half a metre thick in places, although approximately every eight years the lake fills with water. During this time it becomes a prolific water bird breeding area. Only 3 times in the last 150 years has the lake filled to capacity. When full the lake holds more water than Sydney Harbour. It would take the Mississippi River 22 days and the Amazon River 3 days to fill the Lake. The Lake Eyre region of South Australia has the lowest annual mean precipitation of anywhere in Australia with only about 100mm falling. The annual evaporation rate for this area is 2.5 metres.
It is theorised that Lake Eyre was once a permanent lake but due to climate change and a receding water table over many thousands of years it is now dry most of the time. Early European explorers in Eastern Australia found that many rivers appeared to flow unusually westward, away from the coast. This led to a belief in the existence of a great inland sea. The rivers however finally meandered their way to the coast in South Australia and no inland sea was ever found. Perhaps once Lake Eyre was this mythical inland body of water.
The Aboriginal Arabunna people once inhabited the Lake Eyre region and the tribe still believe much of the area to be their historical lands. This group have a dreamtime story, much of which cannot be retold in the presence of the uninitiated, relating to the mystical birth of Lake Eyre. Today the Arabunna and other indigenous groups are fighting to have their lands returned to them.
Lake Eyre’s wide flat saltpan nature has lent it to be the location of land speed record attempts. In 1964 Donald Campbell set a new record of 403.135 mph (648.783 kph) on Lake Eyre with a gas turbine vehicle.
Tourism in the Lake Eyre catchment area is increasing as more people explore the Australian outback. It is feared that this increase may be damaging to some fragile desert eco-systems.