Sources: NASA Earth Observatory, http://earthobservatory.nasa.gov/IOTD/view.php?id=38994 and http://earthobservatory.nasa.gov/IOTD/view.php?id=7076.
South Australia’s Lake Eyre is the lowest point on the continent, and one of its most famed natural wonders. Pictured above are the two extreme of the lake bed. In wet years, it’s one of the twenty largest lakes by area on the planet. But most years, it’s a set of dry salt flats that from above resemble a gaunt, haunting face. In dry years, the lake bed is the largest source of airborne dust particles in the Southern Hemisphere; in wet years (associated with strong La Niña patterns), the lake bed teems with life.
The lake is composed of two different sections: Lake Eyre North (the ‘eyes’ of the ‘face’), which is 144 x 77 km (89 x 48 mi), and Lake Eyre South (the ‘mouth’), which is 64 x 24 km (40 x 15 mi). The ‘nose’ of the face, Goyder Channel, joins the two basins together in wet years. When dry, the lowest part of the exposed lake bed salt flats is the lowest point on Australia’s surface at 15.2 m (49.9 ft) below sea level. Naturally, being this low means that Lake Eyre serves as a catch-all for excess runoff from outback streams during period of flooding.At 1 140 000 km2 (440 150 sq mi), Lake Eyre has one of the largest endorheic drainage basins on the planet. For the past 25 000 years or so, light flooding has occurred generally every three years to a depth of 1.5 m (5 ft), and major flooding occurs every decade.
When Lake Eyre fills, the clear water reflects the sky to a degree that it becomes very difficult for airplane pilots to discern the difference between the sky and the lake. Source: D. Shearman, http://www.flickr.com/photos/donshearman/4940450749/. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) licence.
The salt below the surface produces a wide array of colours when flooded. Source: A. Knecht, http://www.flickr.com/photos/knecke/5567679836/ and http://www.flickr.com/photos/knecke/5567678732/in/photostream/ .Licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) licence.
Source: nic_pepsi, http://www.flickr.com/photos/nic_pepsi/3811415958/. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) licence.
The Lake Eyre drainage basin. Source: Kmusser, http://commons.wikimedia.org/wiki/File:Lake_eyre_basin_map.png. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported licence.
Despite only filling three times during the entire 20th century, the past three years have seen the lake filled up past the three-quarter mark (this year, in fact, saw the highest lake levels since 1974 as the lake was completely filled); a product of the same weather patterns that caused extensive flood damage in Queensland. Water in southwest Queensland west of the Great Dividing Range enters Lake Eyre’s drainage basin from up to 1,300 km (808 mi) away during major floods.The massive surplus of floodwater has filled up the lake to such a point that it will stick around for at least two more years. This will result in an explosion of life in the desert, as freshwater in the flooded lake bed supports the breeding of hundreds of thousands of birds. With the floods over, the lake, what has already re-separated into a number of smaller lakes, is back down from its 35-year-high-end depth of 4 metres-plus (13 ft) down to a current maximum of around 1.9 m (6 ft), but that’s still higher than usual, and still more than enough for the Lake Eyre Yacht Club. Yes, there is a rather dedicated group of sailors who, when parts of the lake are full enough, head out to sail the basin. Most members use catamarans and dinghys, but other types of watercraft are seen as well. The water hasn’t been deep enough for high-powered motors since the 1974 flood, however.
ABC News (2011). Flooding and storms fill outback lake. 9 March 2011. Available at http://www.abc.net.au/news/2011-03-09/flooding-and-storms-fill-outback-lake/2663296. Accessed 2 October 2011.
Baker, R. (2010). Lake Eyre floods again. Australian Geographic, 15 July 2010. Available at http://www.australiangeographic.com.au/journal/lake-eyre-floods-again.htm/. Accessed 1 October 2011.
Desert Channels Queensland Inc. (2005). Lake Eyre Basin. Available at http://www.lakeeyrebasin.org.au/. Accessed 1 October 2011.
International Lake Environment Committee (2008). Lake Eyre. Available at http://www.ilec.or.jp/database/oce/oce-04.html. Accessed 2 October 2011.
Kotwicki, V. (2009). Lake Eyre basics. Floods of Lake Eyre. Available at http://www.k26.com/eyre/The_Lake/Papers/Lake_Eyre_basics/lake_eyre_basics.html. Accessed 1 October 2011.
NASA Earth Observatory (2006) .Ghostly Face In South Australian Desert. 1 November 2006. Available at http://earthobservatory.nasa.gov/IOTD/view.php?id=7076. Accessed 2 October 2011.
Phillips, A. and C. Arthur (2011). Lake Eyre gets another big drink. ABC Western Queensland, 14 March 2011. Available at http://www.abc.net.au/local/stories/2011/03/14/3163423.htm. Accessed 2 October 2011.
Riebeek, H. (2009). Lake Eyre Filling Peaks. NASA Earth Observatory, 21 June 2009. Available at http://earthobservatory.nasa.gov/IOTD/view.php?id=38994. Accessed 2 October 2011.
Todd, A. (2011). Lake Eyre filling up fast, thanks to Queensland floods. Herald Sun, 4 January 2011. Available at http://www.heraldsun.com.au/ipad/lake-eyre-filling-up-fast-thanks-to-queensland-floods/story-fn6bfkm6-1225981344559. Accessed 2 October 2011.