The Lake Eyre basin ( ) is a

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

that covers just under one-sixth of all

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. It is the largest

endorheic basin An endorheic basin ( ; also endoreic basin and endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water (e.g. rivers and oceans); instead, the water drainage flows into permanent ...

in Australia and amongst the largest in the world, covering about , including much of inland

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

, large portions of

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

and the

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

, and a part of western

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

. 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 Wildlife refers to domestication, undomesticated animals and uncultivated plant species which can exist in their natural habitat, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introdu ...

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

landmass A landmass, or land mass, is a large region or area of land that is in one piece and not noticeably broken up by oceans. The term is often used to refer to lands surrounded by an ocean or sea, such as a continent or a large island. In the fiel ...

mostly covered by forest and contained many more lakes than now. The climate has changed from wet to arid over the last 60 million years. Most of the rivers in the Lake Eyre basin are now slow flowing, flat, and completely dry for lengthy periods. When the country north of the basin floods, floodwaters drain via the main rivers of the basin— Cooper Creek, Georgina River, and Diamantina River—southwards towards Kati Thanda–Lake Eyre, the country's lowest point at below sea level. The water overflows the river banks, across the

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s, filling waterholes and

wetlands A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

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' jurisdictions. As the ecological significance of the basin has become known and mismanagement of another Australian basin, 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, which was set up to ensure the sustainability of the Lake Eyre Basin river systems. In 2014, the

Queensland Government The Queensland Government is the state government of Queensland, Australia, a Parliament, parliamentary constitutional monarchy. Government is formed by the party or coalition that has gained a majority in the Queensland Legislative Assembly, ...

changed the laws protecting the rivers and floodplains. there are fears that mining for coal seam gas could be very detrimental to the fragile environment of the floodplains.

Geology

The basin began to form in the early

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

(about 60 million years ago) when south-eastern South Australia started to sink and rivers began to deposit

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

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. The basin is still gradually sinking, and still gradually accumulating sediment. For many millions of years, the Lake Eyre Basin was well-supplied with water and largely

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

ed. 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 age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

s bring about the present climatic regime and the consequent fairly rapid

desertification Desertification is a type of gradual land degradation of Soil fertility, fertile land into arid desert due to a combination of natural processes and human activities. The immediate cause of desertification is the loss of most vegetation. This i ...

of the area. The basin covers just under one-sixth of all Australia and is the largest

in Australia and amongst the largest in the world, covering about , including much of inland

, large portions of

and the

, and a part of western

Geography

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 below

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

, and usually contains only salt. In flood years, it fills and, for a short time, undergoes a period of rapid growth and fertility: long-dormant marine creatures multiply and large flocks of waterfowl arrive to feed and raise their young before the

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

s evaporate once more. The annual mean runoff in the Lake Eyre Basin is the lowest of any of the world's major drainage basins. 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 , and the pan evaporation rate is . Annualised average figures are misleading: since 1885, annual rainfall over the of the Lake Eyre Basin has ranged from about in 1928 to over in 1974. Most of the water reaching Lake Eyre comes from the river systems of semi-arid inland Queensland, roughly 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. (In contrast, the flow of the

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

could fill Lake Eyre in 22 days, that of the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

in just three days.) 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. It supports about 60,000 people and a large amount of

, and has no major irrigation, diversions, or flood-plain developments.

Rivers

The Cooper Creek, Finke River, Georgina River, and Diamantina River are the four main rivers of the basin. Other desert rivers include the Hale River, Plenty River, and

Todd River The Todd River (Arrernte language, Arrernte: ''Lhere Mparntwe / Lhere Imatukua / Artepe Ulpaye'') is an Ephemeral, ephemeral river in the southern Northern Territory, central Australia. The origins of the Todd River are in the MacDonnell Ranges ...

that flow from the southeast 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 flow rate, and a naturally turbid water quality. Several of the major Lake Eyre Basin river systems are well-known. Because the Lake Eyre Basin is almost flat, rivers flow slowly and frequently split up into

s or braided channels. Water is lost to evaporation, to seepage, and in the many ephemeral

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

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 Finke River, starting roughly west of

Alice Springs Alice Springs () is a town in the Northern Territory, Australia; it is the third-largest settlement after Darwin, Northern Territory, Darwin and Palmerston, Northern Territory, Palmerston. The name Alice Springs was given by surveyor William ...

, 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 The Simpson Desert is a large area of dry, red sandy plain and dunes in the Northern Territory, South Australia and Queensland in central Australia. It is the fourth-largest Deserts of Australia, Australian desert, with an area of . The Wangka ...

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 . Major tributaries include Ellery Creek and the Palmer and Hugh Rivers. The Georgina River system originates on the Barkly Tableland, near the Northern Territory–Queensland border, northwest of Mount Isa and not far south of the

Gulf of Carpentaria The Gulf of Carpentaria is a sea off the northern coast of Australia. It is enclosed on three sides by northern Australia and bounded on the north by the eastern Arafura Sea, which separates Australia and New Guinea. The northern boundary ...

. In this relatively humid northern area, rainfall can be as high as per year and evaporation as low as . The Georgina flows through innumerable channels leading south through far-western Queensland for over , eventually reaching Goyder Lagoon in the northeastern corner of South Australia. Australia's early bush poets immortalised the Diamantina River, making it a symbol of the remote outback. It too rises in northern Queensland, roughly between Mount Isa and Winton, flowing 800 kilometres south and west through Birdsville and the Channel Country to join the Georgina at Goyder Lagoon (and then, if there is sufficient flow, down Warburton Creek towards Lake Eyre). Of all the Lake Eyre Basin river systems, however, Cooper Creek is by far the most famous, in particular because it was along Cooper Creek that the explorers Burke and Wills met their deaths. It rises in the form of two central Queensland rivers, the Thomson between Longreach and Charters Towers, and the Barcoo in the area around Barcaldine, about inland from

Rockhampton Rockhampton is a city in the Rockhampton Region of Central Queensland, Australia. In the , the population of Rockhampton was 79,293. A common nickname for Rockhampton is "Rocky", and the demonym of Rockhampton is Rockhamptonite. The Scottish- ...

. Cooper Creek spreads out into a vast area of meandering ephemeral channels, making its way roughly south into the far southwest corner of Queensland before turning due west into South Australia towards Lake Eyre. It takes almost a year for water to reach Lake Eyre from the

headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

. In most years, none does: it is absorbed into the earth, goes to fill channels and the many permanent waterholes, or simply evaporates. Water from Cooper Creek reached Lake Eyre in 1990 and then not again until 2010.

Deserts

The deserts that have formed in the basin, including

Sturt Stony Desert Sturt Stony Desert (previously Sturt's Stony Desert) is an area in the north-east of South Australia, far south western border area of Queensland and the far west of New South Wales. It was named by Charles Sturt in 1844, while he was trying ...

Tirari Desert The Tirari Desert is a desert in the eastern part of the Far North region of South Australia. It stretches 212 km from north to south and 153 km from east to west. Location and description The Tirari Desert features salt lakes and ...

, and the Strzelecki Desert, are most probably the southern hemisphere's largest source of airborne dust.

Fauna

A total of 27 individual species of fish are found in Lake Eyre basin, with 13 of them being endemic. The largest fish species is the Macquaria, reaching a maximum weight of about .

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

. The Wangkangurru language region was traditionally in the South Australia–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.

Management

Indigenous Australians have lived with the cycles of the land for thousands of years and traditional owners are protective of its natural systems. Management of the area has been problematic as it is covered by four different states' jurisdictions. As the 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. 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. On 7 September 2018, the Lake Eyre Basin Ministerial Forum agreed to release the second review of the agreement.

Land use and mining

Low-density grazing is the major land use, occupying 82% of the total land within the basin. Significant minerals deposits such as oil and natural gas, including Australia's most significant onshore petroleum reserves, are found within the basin. The mining and petroleum industries account for the greatest economic activity in the Lake Eyre Basin.

Opal Opal is a hydrated amorphous form of silicon dioxide, silica (SiO2·''n''H2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a ...

s, coal,

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

, gypsum, and

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

are also mined from the basin. 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. The spill has the potential to contaminate parts of the basin as far south as Lake Eyre. In 2014, the

changed the laws protecting the rivers and floodplains, which, according to

environmentalist Environmentalism is a broad Philosophy of life, philosophy, ideology, and social movement about supporting life, habitats, and surroundings. While environmentalism focuses more on the environmental and nature-related aspects of Green politics, g ...

s, could lead to shale gas mining or fracking in the area. there are fears that mining for coal seam gas could be very detrimental to the fragile environment of the floodplains.

Protected areas

The Kati Thanda–Lake Eyre National Park, Strzelecki Regional Reserve, Witjira National Park, Sturt National Park, Diamantina National Park, and Simpson Desert National Park are among a number of protected areas established within the Lake Eyre Basin.

River diversion schemes

The Bradfield Scheme was an ambitious proposal by Dr John Bradfield in 1938. It would use large

pipes Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circu ...

, tunnels, pumps, and dams to divert water from the

monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...

-fed Tully, Herbert, and Burdekin rivers into the Thomson River,

. 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.