The Bulloo River is an isolated drainage

Drainage

Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies.-Early history:...

 system in western Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

, central Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. Its floodplain

Floodplain

A floodplain, or flood plain, is a flat or nearly flat land adjacent a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge...

, which extends into northern New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

, is an important area for waterbirds when inundated.

Description

The Bulloo is the only river in the region not part of either the Murray-Darling Basin

Murray-Darling Basin

The Murray-Darling basin is a large geographical area in the interior of southeastern Australia, whose name is derived from its two major rivers, the Murray River and the Darling River. It drains one-seventh of the Australian land mass, and is currently by far the most significant agricultural...

 or the Lake Eyre Basin

Lake Eyre Basin

The Lake Eyre basin is a drainage basin that covers just under one-sixth of all Australia. The Lake Eyre Basin is the largest endorheic basin in Australia and amongst the largest in the world, covering about 1,200,000 square kilometres, including much of inland Queensland, large portions of South...

; instead it flows into several ephemeral lakes which are blocked by low hills from reaching either Lake Frome

Lake Frome

Lake Frome is a large endorheic lake in South Australia, east of the Northern Flinders Ranges. It is a large, shallow, unvegetated salt pan, 100 km long and 40 km wide, lying mostly below sea level and having a total surface area of 259,615 hectares...

 or the Paroo River

Paroo River

The Paroo River is a river in Eastern Australia and is often considered to be major tributary of the Darling River in eastern Australia, although its flow generally dissipates before it reaches the Darling...

. In its lowest reaches, which extend to near Tibooburra in New South Wales

New South Wales

New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

, is the distributary known as Bella Creek. It is believed that in past wet periods the Bulloo has had connections to Lake Frome because its fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 fauna resembles that of the Lake Eyre Basin rather than that of the Murray-Darling Basin. Several tributaries flow into the Bulloo in its upper reaches, the largest being Blackwater Creek. Ranges of low hills prevent the lower reaches of the Bulloo from receiving significant tributaries.

Hydrology

Hydrologically, the Bulloo is very similar to the Darling River

Darling River

The Darling River is the third longest river in Australia, measuring from its source in northern New South Wales to its confluence with the Murray River at Wentworth, New South Wales. Including its longest contiguous tributaries it is long, making it the longest river system in Australia.The...

 and Cooper Creek

Cooper Creek

Cooper Creek is one of the most famous and yet least visited rivers in Australia. It is sometimes known as the Barcoo River from one of its tributaries and is one of three major Queensland river systems that flow into the Lake Eyre Basin...

. It is usually completely dry except for water holes, but during years of strong monsoonal activity in the summer the Bulloo can flood heavily to discharges of more than 1000 m³/s, and annual flows of up to five times the mean. In dry years annual rainfall can be as low as 100mm (4 inches) throughout the basin and years of zero runoff are not unknown.

Climate

Annual rainfall throughout the basin ranges from 330 mm (13 inches) in the north to 200 mm (8 inches) in the south, with the northward increase being due to higher falls in the summer. In the winter, rainfall is rare throughout the basin, with the average between April and October generally around 115 mm (4.5 inches), though on extremely rare occasions such as 1920-1921 and 1956 the river has had a significant flood during the winter. The basin was flooded in the March 2010 Queensland floods.

Temperatures in the summer are extreme throughout except during monsoonal activity, with mean maxima around 38°C (100°F) in January and minina around 23°C (74°F). In the winter maxima remain warm, ranging from 20°C (68°F) in the south to 25°C (77°F) in the north, but frost

Frost

Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...

s are not unknown at night.

Environment

The Bulloo basin is used almost exclusively for the extensive grazing of sheep and cattle

Cattle

Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

. The only towns within the basin are the former opal

Opal

Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...

 mining town of Quilpie

Quilpie, Queensland

-External links:* *...

 and, further downstream, Thargomindah

Thargomindah, Queensland

- External links:* * * *...

. There is only one major protected area, Idalia National Park

Idalia National Park

Idalia is a national park in Queensland , 893 km west of Brisbane. Idalia National Park is located near the town of Blackall in the Queensland outback. The park protects 144,000 hectares of mulga lands with conservation value...

, in the entire basin, located in the river's headwaters.

The Bulloo floodplain, with an area of about 9240 km² is classified by BirdLife International

BirdLife International

BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...

 as an Important Bird Area

Important Bird Area

An Important Bird Area is an area recognized as being globally important habitat for the conservation of bird populations. Currently there are about 10,000 IBAs worldwide. The program was developed and sites are identified by BirdLife International...

. When it floods the site supports several hundred thousand waterbirds, with over 1% of the populations of Red-necked Avocet

Red-necked Avocet

The Red-necked Avocet is a water bird found throughout Australia, except for the northern parts of the Northern Territory....

, Grey Teal

Grey Teal

The Grey Teal, Anas gracilis is a dabbling duck found in open wetlands in New Guinea, Australia, New Zealand, Vanuatu and Solomon Islands....

, Australasian Shoveler

Australasian Shoveler

The Australasian Shoveler is a species of dabbling duck in the genus Anas. It ranges from 46–53 cm. It lives in heavily vegetated swamps. In Australia it is protected under the National Parks and Wildlife Act, 1974...

, Pink-eared Duck

Pink-eared Duck

The Pink-eared Duck is a species of duck found in Australia.It has a large spatulate bill like the Australasian Shoveler, but is smaller at 38–40 cm length. Its brown back and crown, black and white barred sides and black eye patches on its otherwise white face make this bird unmistakable...

 and Freckled Duck

Freckled Duck

The Freckled Duck is a moderately large, broad-bodied duck native to southern Australia. The duck is protected by law...

. It also contains the entire population of a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the Grey Grasswren

Grey Grasswren

The Grey Grasswren is a species of bird in the Maluridae family.It is endemic to Australia.-References:* BirdLife International 2004. . Downloaded on 25 July 2007....

.