Cooper Creek

• Category: Inland Aquatic Biomes.
• Geographic Location: Australia.
• Summary: This iconic watercourse through arid Australia fills with biodiversity when it floods, and provides a reminder of the devastating difficulties that Australia's early explorers faced.

The Cooper Creek is one of Australia's most iconic rivers, flowing from the western slopes of the Great Dividing Range around Longreach/Charters Towers as the Thomson and Wilson Rivers, and through the Queensland channel country from Barcaldine, as the Barcoo. Then it continues on a slow meander westward along the flat lands past Innamincka, and ultimately into Lake Eyre. It is perhaps the only waterway in the world with three rivers flowing into it to form a creek. But this flow rate is deceptive; in most years, the Cooper is an ephemeral channel that flows briefly after rainfall—with a mean precipitation of five inches (125 millimeters) per year—that evaporates long before it flows into Lake Eyre. When it does flood, however, the Cooper can be 25 miles (40 kilometers) wide at Windorah—and a cataract equal to three times the amount of water in Sydney Harbor flows over the Cooper Creek causeway at Innamincka daily in such conditions.

The Cooper, 882 miles (1,420 kilometers) long, is the second-longest inland river system in Australia (after the Murray-Darling). Cooper Creek drains the eastern side of the catchment of the Lake Eyre Basin; at 451,740 square miles (1,170,000 square kilometers), the catchment is the world's third-largest terminal lake system and is thought to be the world's largest salt pan.

The flooding rains of the summer of 2010–11 brought the Cooper into very heavy flood. The flat topography of the region meant that the water took six months to flow the 250 miles (400 kilometers) from Innamincka to Lake Eyre.

Vegetation

During the Tertiary, the Cooper flowed through an environment of forest, but as Australia dried during the continent's slow drift northward, this environment turned into a narrow band of coolabah (Eucalyptus coolabah) and lignum (Muelhenbeckia spp.) snaking between the sand dunes and gibber plains of the Strzelecki, Sturt's Stony, and Tarari Deserts. Further from the coolabah riparian zone and lignum thickets, the vegetation becomes dominated by chenopod shrublands and hummock grasslands, with Mitchell grass on the gibber plains and Dodonea spp., sandhill wattles, and sandhill canegrass on the dunes.

Wildlife

During floods, the Cooper becomes filled with waterbirds that fly in from great distances away to plunder the creek's bounty. When the creek is full of water, invertebrates like brine shrimp quickly breed to supply food for Australia's only inland fishery, an industry that targets golden perch, bony bream, catfish, grunters, and yabbies (a freshwater crawfish). Bird species such as Australian pelicans, cormorants, darters, egrets, ibises, grebes, stilts, and the endemic Australian black swans move in to access these riches. Countless duck species join them; these include pink-eared, shelducks, hardheads, and grey teals.

Following flooding times, the surrounding areas become resource-rich environments, with increases in rodent numbers and huge flocks of black kites (Milvus migrans) soaring overhead, looking for a meal of mouse or fish. Many of the farms in the region target dingoes (Canis lupus dingo) for fear of their effects on livestock. Dingoes, however, probably reduce the effect of foxes and cats on native fauna, so their retention in the environment can certainly be beneficial to wildlife.

Human Activity and Conservation

The Cooper was named after the chief justice of South Australia, Charles Cooper, by explorer Charles Sturt during his travels through inland Australia in 1845. The Burke and Wills expedition to the Gulf of Carpentaria essentially ended on the Cooper, when Robert O'Hara Burke and William John Wills failed to follow the preparation methods of the local Yauraworka and Yantruwantra Aboriginal people in making nardoo sporocarp seedcakes; they died alongside a waterhole of beriberi, likely of thiamine deficiency. John King, the sole survivor of the expedition, accepted the Aboriginal people's offers of assistance and survived to tell the tale.

Despite the region's aridity, isolated permanent water sources allowed large populations of Aboriginal people to exist along these inland waterways. Within a decade of European exploration, pastoral stations were established, and by 1900, the Aboriginal population had been reduced by 90 percent, to 30 survivors.

Nowadays, the majority of the Cooper is flanked by pastoral stations until it flows into Lake Eyre. The Cooper affords little to the pastoralists unless it is flooding; then it yields a boom time for cattle, which normally receive their water from bores dug into the Great Artesian Basin. The Birdsville Track crosses the Cooper on Mulka Station, and during flood times, a two-vehicle punt is needed to cross the creek. Helicopter tours and river cruises are available from the campsite at the punt, attesting to the amount of tourism the region experiences during times of flood.

The Cooper has been proposed for listing as a Wild River under Queensland government protection. This listing would improve the conservation status of the iconic river, which currently is poorly conserved and heavily affected by pastoralism. In 2011, the government announced that Cooper's Creek would be permanently protected, along with the Georgina and Diamantina rivers. The creek was declared a wild river under the Wild Rivers Act. The announcement protected ten million acres in western Queensland between the three bodies of water. Innamincka Regional Reserve, at 3.2 million acres (1.3 million hectares), is the primary conservation area on the Cooper, but farming and mining are both allowed in the reserve, reducing its value for conservation.

Coongie Lakes National Park is within the regional reserve; it is a wetland of international importance under the Ramsar Convention, and was identified as an Important Birding Area because it supports more than 1 percent of the global populations of 12 species of waterbirds and waders, as well as significant numbers of Bourke's parrots, Eyrean grasswrens, gibberbirds, banded whitefaces, chirruping wedgebills, and cinnamon quail-thrushes.

Climate change in the coming decades is expected to tax the Cooper Creek hydrological system to the tune of about 10 percent of its water volume. Lower rainfall, higher average temperatures, and greater evaporation rates may combine to reduce the life-supporting capacity of a number of its stretches and waterholes; various grass species and many animal types will be under duress as this scenario progresses. The floodplain itself may contract, as flooding events may not reach the extremes that have been recorded in the past on a regular basis—this trend, however, could readily be disrupted by short-term extreme weather events much like the summer flood of 2010–11.

Bibliography

Badman, F. J. The Birds of Middle and Lower Cooper Creek in South Australia. Adelaide: Nature Conservation Society of South Australia, 1989.

Cobon, D. H. and N. R. Toombs. Climate Change Impacts on the Water Resources of the Cooper Creek Catchment. Brisbane, Australia: Department of Natural Resources and Water, Climate Change Centre of Excellence, 2006.

Ellis, R. Boats in the Desert. Rockhampton, Australia: Queensland University Press, 2006.

“Protection of Cooper’s Creek, Georgina, and Diamantina Rivers Hailed as Momentous.” PEW Trust, 9 Dec. 2011, www.pewtrusts.org/en/about/news-room/press-releases-and-statements/2011/12/09/protection-of-cooperand39s-creek-georgina-and-diamantina-rivers-hailed-as-momentous. Accessed 5 Nov. 2024.

Weidenback, K. Mailman of the Birdsville Track: The Story of Tom Kruse. Adelaide, Australia: Hodder, 2006.