Lake Eyre (pronounced "air") is the lowest point in
Australia, at approximately (
AHD) below sea level and, on the rare occasions that it fills, it is the largest
lake in Australia. It is the focal point of the vast
Lake Eyre Basin and is found some 700 km north of
Adelaide.
Geography
The lake was named after
Edward John Eyre who was the first European to sight it in 1840.
The lake is located in the deserts of central Australia, in northern
South Australia. The
Eyre Basin is a large
endorheic system surrounding the lakebed, the lowest part of which is filled with the characteristic
playa salt pan caused by the seasonal expansion and subsequent evaporation of the trapped waters. Even in the dry season there is usually some water remaining in Lake Eyre, usually collecting in a number of smaller sub-lakes on the playa.
During the
rainy season the rivers from the northeast (in
outback Queensland) flow towards the lake through the
Channel Country. The amount of water from the
monsoon determines whether water will reach the lake and if it does, how deep the lake will get. In strong
La Niña years the lake can fill. Since 1885 this has occurred in 1886/1887, 1889/1890, 1916/1917,
1950, 1955, 1974-1976 , with the highest flood of 6m in 1974. Local rain can also fill Lake Eyre to 3-4m as occurred in 1984 and 1989. Wave built shingle terraces on the shore suggest that during the
Medieval Warm Period and centuries immediately prior Lake Eyre possibly held
permanent water at levels above those of 1974. Torrential rain in January 2007 took about six weeks to reach the lake but put only a small amount of water into it.
When recently flooded the Lake is almost fresh. At these times the lake supports native fresh water fish, including
boney bream (
Nematolosa erebi), the Lake Eyre Basin sub-species of
golden perch (
Macquaria ambigua) and various small hardyhead species (
Craterocephalus spp). The salinity increases as the 450mm salt crust dissolves over a period of six months resulting in a massive fish kill. When over 4m deep the Lake is no more salty than the sea and salinity increases as the water evaporates with saturation occurring at about 500mm depth. The Lake takes on a "pink" hue when saturated due to the presence of
beta-carotene pigment caused by the algae
Dunaliella salina.
Typically a 1.5 m (5 ft) flood occurs every three years, a 4 m (13 ft) flood every decade, and a fill or near fill four times a century. The water in the lake soon
evaporates with a minor and medium flood drying by the end of the following summer.
2009
The 2009 Lake Eyre flood peaked at 1.5m deep in late May which is a quarter of its maximum recorded depth of 6m. Nine cubic kilometres of water crossed the Queensland - South Australian border with most of it coming from massive floods in the Georgina River. However the greater proportion soaked into the desert or evaporated en route to the Lake leaving less than one cubic kilometre in the Lake which covered an area of 800 square kilometres or 12% of the Lake. As the flood did not start filling the Lake's deepest point (Belt Bay) until late March, little bird life appeared preferring instead to nest in the upper reaches of the Lake Eyre Basin, north of
Birdsville, where large lakes appeared in January as a result of monsoonal rain.
Yacht club
The
Lake Eyre Yacht Club is a dedicated group of eccentrics who sail on the lake's floods, including recent trips in 1997, 2000, 2001, 2004, 2007 and 2009. A number of 6 m Trailer Sailers sailed on Lake Eyre in 1975, 1976 and 1984 when the flood depth reached 3–6 m.
Land speed record attempts
Campbell Plaque at Level Post Bay
It has been a site for various
land speed record attempts on its
salt flats, especially those by
Sir Donald Campbell with the
Bluebird-Proteus CN7.
See also
