Famous for being the saltiest lake in Australia, Lake Eyre (officially known as Kati Thanda-Lake Eyre) only fills up once or twice every century. The lake itself, at 15 metres below sea level, is Australia's lowest point. It is also the fifth largest (9,690 square kilometres) terminal lake in the world although it usually contains little or no water. The highest recorded level in Lake Eyre was in 1974 but it would take the average flow of Australia's largest river, the Murray to maintain that level. The Danube River would fill Lake Eyre to the 1974 level in forty-five days; the Mississippi in twenty-two days, and the Amazon in three days.
Summer shade temperatures on Lake Eyre regularly reach the fifty degrees Celsius range while a reading of 61 degrees has been reported. The Lake is situated in the most arid part of Australia with a mean annual rainfall of less than 125 mm and an annual evaporation rate of 2.5 metres.
The Lake Eyre Basin covers one sixth of the continent and holds some of the rarest, least exploited ecosystems on the planet. The Basin is the world's largest internal drainage system. It covers approximately 1.2 million square kilometres of arid and semi arid Central Australia. This is about one-sixth of the continent or the same size as the Murray Darling system or about twice the size of the US state of Texas. It is considered to be one of the world's last unregulated, wild river systems. Unlike other river systems, flows in the Basin are highly variable and unpredictable.
All the rivers and creeks are ephemeral with short periods of flow following rain and extended periods of no flow. The volume of flow decreases downstream reflecting increasing aridity towards Lake Eyre and the huge dispersal system of braided channels, floodplains, waterholes and wetlands on the way. The many large permanent waterholes in the system provide vital habitat for wildlife and are important to towns, communities and pastoral holdings. The Basin is part of Australia's arid zone and the ecosystems it supports are varied and often unique. Land use within the Basin is equally varied, and includes (but is not limited to) pastoralism, mining, tourism, oil and gas exploration and production, conservation and Aboriginal activities. The area is culturally significant and contains a wealth of Aboriginal and non-Aboriginal history.
The surface of the lake has an eerie appearance. Because the lake is so clam, it is reflecting am image of the sky and clouds, but this image is coloured by the pink tinge of the algae that lives in the briny waters. The lake contains a series of island and bays. The islands in the lake can contain nesting colonies for birds when the lake holds water as the birds feed on the crustaceans and small fish which inhabit the lake.
British adventurer and speed record chaser Donald Campbell attempted the World Land Speed Record in his car, The Bluebird, on this lake back in the 1960s when the lake was dry. On 17th July 1964, Campbell set a record of 403.10 mph (648.73 km/h) for a four-wheeled vehicle. Campbell was disappointed with the record as the vehicle had been designed for much higher speeds. CN7 covered the final third of the measured mile at an average of 429 mph (690 km/h), peaking as it left the measured distance at over 440 mph (710 km/h).