Lake Eyre basin

Coordinates: 25°59′49″S 137°59′57″E / 25.99686697°S 137.99905382°E / -25.99686697; 137.99905382
Source: Wikipedia, the free encyclopedia.

Lake Eyre basin
Lake Hart is one of the smaller lakes in the basin[1]
Lake Hart is one of the smaller lakes in the basin[1]
Etymology: Lake Eyre; Edward John Eyre
Map of the Lake Eyre Basin showing the major rivers
Map of the Lake Eyre Basin showing the major rivers
CountryAustralia
States and
territories
Area
 • Total1,200,000 km2 (500,000 sq mi)

The Lake Eyre basin (/ɛər/ AIR) is a drainage basin that covers just under one-sixth of all Australia. It is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres (463,323 sq mi), including much of inland Queensland, large portions of South Australia and the Northern Territory, and a part of western New South Wales. The basin is also one of the largest, least-developed arid zone basins with a high degree of variability anywhere. It supports only about 60,000 people and has no major irrigation, diversions or flood-plain developments. Low density grazing that sustains a large amount of wildlife is the major land use, occupying 82% of the total land within the basin. The Lake Eyre basin of precipitation (rain water) to a great extent geographically overlaps the Great Artesian Basin underneath.

The basin began as a sinking

wetlands and carving new channels, giving rise to the name Channel Country
. Most of the rain which falls in the north never reaches the lake 1,000 km away, which only fills occasionally.

Management of the area has been problematic as it is covered by four different states'

Murray-Darling Basin, became apparent during several drought cycles
, it became clear that ongoing management issues had to be resolved. In 2001 the Lake Eyre Basin Intergovernmental Agreement was signed, which was set up to ensure the sustainability of the Lake Eyre Basin river systems.

In 2014, the

coal seam gas could be very detrimental to the fragile environment of the floodplains.[2][3]

Geology

Lake Eyre in 1990, as seen by STS-35

The basin began to form in the early Paleogene (about 60 million years ago) when south-eastern South Australia started to sink and rivers began to deposit sediment into the large, shallow basin. A remnant of an old oceanic plate is currently sinking in the mantle beneath the basin. The suction effect of this sinking likely caused both the Lake Eyre Basin as well as the Murray-Darling basin to form.[4] The basin is still gradually sinking, and still gradually accumulating sediment.[5] For many millions of years, the Lake Eyre Basin was well supplied with water and largely forested. About 20 million years ago, large shallow lakes formed, covering much of the area for about 10 million years. From that time on, as Australia drifted further north and the climate became gradually more arid, the lakes and floodplains started to dry. Only in the last 2.6 million years did the onset of the ice ages bring about the present climatic regime and the consequent fairly rapid desertification of the area.

The basin covers just under one-sixth of all Australia[6] and is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres (463,323 sq mi),[7] including much of inland Queensland, large portions of South Australia and the Northern Territory, and a part of western New South Wales.[8]

Geography

Strzelecki Desert, South Australia

During years of especially high

rainfall, all the riverbeds in this vast, mostly flat, arid and semi-arid area lead inland (not towards the sea) towards Lake Eyre
in central South Australia.

Lake Eyre itself lies approximately 16 metres (52 ft) below

waterfowl arrive to feed and raise their young before the waters evaporate once more. The annual mean runoff in the Lake Eyre Basin is lowest of any of the world's major drainage basins.[9]

None of the creeks and rivers in the Lake Eyre Basin are permanent: they flow only after heavy rain – a rare to very rare event in the arid interior of Australia. Average annual rainfall in the area surrounding Lake Eyre is 125 millimetres (4.9 in), and the pan evaporation rate is 3.5 metres (11 ft). Annualised average figures are misleading: since 1885 annual rainfall over the 1,100,000 square kilometres (420,000 sq mi) of the Lake Eyre Basin has ranged from about 45 millimetres (1.8 in) in 1928 to over 760 millimetres (30 in) in 1974. Most of the water reaching Lake Eyre comes from the river systems of semi-arid inland Queensland, roughly 1,000 kilometres (620 mi) to the north.

To provide a sense of scale, the Lake Eyre Basin is about the size of France, Germany and Italy combined. It is slightly larger than the

Murray-Darling basin (which drains inland eastern Australia and is responsible for a large proportion of the continent's agricultural productivity) but has vastly less water. Nevertheless, the entire flow of the Murray-Darling would be insufficient to fill Lake Eyre, merely keeping pace with evaporation.[citation needed] (In contrast, the flow of the Mississippi could fill Lake Eyre in 22 days, that of the Amazon in just three days.[citation needed
])

Other lakes in the basin include Lake Frome, Lake Yamma Yamma and Lake Hart.

The basin is also one of the largest, least-developed arid zone basins with a high degree of variability anywhere.[6] It supports about 60,000 people and a large amount of wildlife, and has no major irrigation, diversions or flood-plain developments.[10]

Rivers

The

Plenty River and Todd River that flow from the south east of the Northern Territory, south. In the western parts of the basin the Neales River and Macumba River
flow into Lake Eyre.

Rivers within the basin have a low gradient, slow

seepage, and in the many ephemeral wetland
systems, with the result that downstream flows are typically smaller than upstream flows. Only in exceptional years is there sufficient upstream rain to provide a flow into Lake Eyre itself.

The

Alice Springs is thought to be the oldest riverbed in the world and although it flows for only a few days a year (in many years it does not flow at all) is home to seven species of fish, two of which are found nowhere else. The waters of the Finke disappear into the sands of the Simpson Desert and are not definitely known to ever make it as far south as Lake Eyre, although the story is told that this happened once early in the 20th century. In extreme events, water from the Finke River flows into the Macumba River, which empties into Lake Eyre, a total distance from headwater streams of around 750 km (470 mi). Major tributaries include Ellery Creek, and the Palmer and Hugh Rivers.[citation needed][citation needed
]

The Georgina River system originates on the Barkly Tableland, near the Northern Territory-Queensland border, north-west of Mount Isa and not far south of the Gulf of Carpentaria. In this relatively humid northern area, rainfall can be as high as 500 millimetres (20 in) per year and evaporation as low as 2.4 metres (7 ft 10 in). The Georgina flows through innumerable channels leading south through far-western Queensland for over 1,000 kilometres (620 mi), eventually reaching Goyder Lagoon in the north-eastern corner of South Australia.

Australia's early

Warburton Creek
towards Lake Eyre).

Of all the Lake Eyre Basin river systems, however,

evaporates. Water from Cooper Creek reached Lake Eyre in 1990 and then not again until 2010.[12]

Deserts

The deserts that have formed in the basin, including Sturt Stony Desert, Tirari Desert and the Strzelecki Desert, are most probably the southern hemisphere's largest source of airborne dust.[13]

Fauna

A total of 27 individual species of fish are found in Lake Eyre basin, with 13 of them being endemic.[14] The largest fish species is the Macquaria, reaching a maximum weight of about 3 kilograms (6.6 lb).[15]

Traditional owners

Wangkangurru (also known as Arabana/Wangkangurru, Wangganguru, Wanggangurru, Wongkangurru) is an Australian Aboriginal language spoken on Wangkangurru country. It is closely related to Arabana language of South Australia. The Wangkangurru language region was traditionally in the South Australian-Queensland border region taking in Birdsville and extending south towards Innamincka and Lake Eyre, including the local government areas of the Shire of Diamantina as well as the Outback Communities Authority of South Australia.[16]

Management

Indigenous Australians have lived with the cycles of the land for thousands of years and

traditional owners are protective of its natural systems.[10]

Management of the area has been problematic as it is covered by four different states'

ecological significance of the basin has become known and mismanagement of the Murray-Darling Basin became apparent during several drought cycles, it became clear that ongoing management issues had to be resolved. In 2001 the Lake Eyre Basin Intergovernmental Agreement was signed, and the Lake Eyre Basin Intergovernmental Agreement was set up to ensure the sustainability of the Lake Eyre Basin river systems, particularly to avoid or eliminate cross-border impacts. The Lake Eyre Basin Ministerial Forum was established as the decision making body responsible for overseeing of the Agreement.[17] The Ministerial Forum created a Community Advisory Committee to provide advice and facilitate community participation and a Scientific Advisory Panel to advise on scientific and technical issues.[17] On 7 September 2018 the Lake Eyre Basin Ministerial Forum agreed to release the second review of the agreement.[18]

Land use and mining

Low density grazing is the major land use, occupying 82% of the total land within the basin.[11] Significant minerals deposits such as oil and natural gas, including Australia's most significant onshore petroleum reserves, are found within the basin.[19] The mining and petroleum industries account for the greatest economic activity in the Lake Eyre Basin. Opals, coal, phosphate, gypsum and uranium are also mined from the basin.[19]

In 2009, the Queensland Environmental Protection Agency confirmed that heavy metals from mining operations near Mount Isa had entered the upper reaches of the Georgina River.[20] The spill has the potential to contaminate parts of the basin as far south as Lake Eyre.

In 2014, the Queensland Government changed the laws protecting the rivers and floodplains, which, according to environmentalists, could lead to shale gas mining or fracking in the area.[10]

As of 2022 there are fears that mining for

coal seam gas could be very detrimental to the fragile environment of the floodplains.[21]

Protected areas

The

Simpson Desert National Park
are among a number of protected areas established within the Lake Eyre Basin.

River diversion schemes

Main article: Bradfield Scheme

The Bradfield Scheme was an ambitious proposal by

Thomson River, Queensland
. After a critical review in 1947 support for the scheme fell through. However, in the 2010s interest in various updated or amended Bradfield schemes have increased among various politicians.

Other less-developed diversion schemes have been proposed to divert river or sea water into the Lake Eyre Basin from time to time.[22]

See also

References

  1. ^ "Location Showcase". South Australian Film Corporation. Retrieved 5 March 2007.
  2. ^ Davey, Alistair; Pegasus Economics; Lock the Gate Alliance (3 October 2022). "Unconventional gas in the Lake Eyre Basin". Lock the Gate Alliance. Archived from the original on 9 January 2023. Retrieved 9 January 2023.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  3. ^ Lowe, Ian (6 February 2022). "Emissions from potential gas development, Queensland Lake Eyre Basin". Lock the Gate Alliance. Archived from the original on 9 January 2023. Retrieved 9 January 2023.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  4. doi:10.1016/j.epsl.2015.03.036
    .
  5. ISBN 0 646 07 183 1
  6. ^ a b Chrissy Arthur (2 June 2009). "Lake Eyre Basin needs more support: study". ABC News. Australian Broadcasting Corporation. Retrieved 1 July 2009.
  7. ^ Map of the Lake Eyre basin Archived 2009-02-20 at the Wayback Machine
  8. ^ Lake Eyre Basin Archived 2009-02-20 at the Wayback Machine. Department of the Environment, Water, Heritage and the Arts.
  9. ISBN 1444300741
    . Retrieved 20 December 2012.
  10. ^ a b c Schwartz, Dominique (9 May 2019). "Wild Abandon". ABC News. Photography by Brendan Esposito. Australian Broadcasting Corporation. Retrieved 9 May 2019.
  11. ^ a b "Australian Catchment, River and Estuary Assessment 2002 - Integrated findings: Lake Eyre Drainage Division". Australian Natural Resources Atlas. Department of the Environment, Water, Heritage and the Arts. Archived from the original on 22 October 2009. Retrieved 3 July 2009.
  12. ABC News Online
    . Australian Broadcasting Corporation. Retrieved 29 September 2010.
  13. ^ "Ghostly Face In South Australian Desert". NASA Earth Observatory. Archived from the original on 2 November 2006. Retrieved 23 June 2008.
  14. ISBN 0195079582
    . Retrieved 20 December 2012.
  15. ISBN 064309606X
    . Retrieved 20 December 2012.
  16. CC-BY-4.0 licensed text from: "Wangkangurru". Queensland Aboriginal and Torres Strait Islander languages map. State Library of Queensland
    . Retrieved 23 January 2020.
  17. ^
    Commonwealth of Australia. Archived from the original
    on 17 October 2016. Retrieved 1 July 2009.
  18. ^ "Lake Eyre Basin Intergovernmental Agreement". Lake Eyre Basin. Retrieved 9 May 2019.
  19. ^
    Commonwealth of Australia
    . 7 October 2008. Retrieved 1 July 2009.
  20. ABC News Online
    . Australian Broadcasting Corporation. 9 March 2009. Retrieved 12 August 2009.
  21. ^ Slezak, Michael (3 October 2022). "Future gas exploration in Lake Eyre could upset the 'greatest desert river system in the world' forever, research shows". ABC News. Australian Broadcasting Corporation. Retrieved 9 October 2022.
  22. ISBN 978-0-643-09442-0
    .

Further reading
  • Kotwicki, Vincent. Floods of Lake Eyre website containing much data, including Lake Eyre inflows 1885–2012
  • Schwarz, Dominique (10 May 2019). "The re-birth of Lake Eyre" (video). ABC News. 7:30 Report. Australian Broadcasting Corporation.

25°59′49″S 137°59′57″E / 25.99686697°S 137.99905382°E / -25.99686697; 137.99905382

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