In the South Australian arid lands water is the magnet that attracts people, biodiversity and industry. It is the key resource in an otherwise dry environment. For a region where rainfall is so low, there is an amazing ability to support a huge diversity of life through a phenomenon known as ‘boom and bust’.
The northern part of the region is dominated by four major catchments – Neales-Peake, Cooper Creek, Georgina-Diamantina, and Macumba – large surface draining networks which terminate at Lake Eyre. ‘Boom’ periods are triggered when floodwaters from interstate and major rainfall events enter the catchments and recharge the region’s lakes, dams and wetlands including the Ramsar-listed, Coongie Lakes. Plants regenerate and waterbirds and fish use the opportunity to breed in large numbers attracting thousands of visitors wishing to experience this unique phenomenon. During frequent and prolonged droughts or ‘bust’ periods, water bodies with permanent fresh water such as Algebuckina Waterhole in the Neales River catchment and Cullyamurra Waterhole in the Cooper Creek catchment provide critical refuge for plants and animals.
In the southern part of the region, including the Gawler Ranges and North Flinders, the rainfall is low and the catchments are generally small. Surface water flows are generated on hilly-rocky headwaters and the majority is rapidly lost as the flows pass onto the plains or into shallow terminal lakes where it is lost through evaporation. The water resources of the region are, to a large extent, unmodified and in good condition. However, there are increasing water requirements in the region from a variety of sources such as from pest species, the tourism sector, and the mining industry. In such an unpredictable climate with high variability from year to year, and with so much life dependent on a healthy water supply, careful management of water in the region is critical.
Lake Eyre Basin
The Lake Eyre Basin covers about 1.2 million square kilometres, almost one-sixth of Australia, and is among the world's largest internally draining river systems. Lake Eyre itself is the fifth largest terminal lake in the world. The Basin includes large parts of South Australia, the Northern Territory, Queensland and some of western New South Wales and is considered one of the world's last unregulated wild river systems. The vegetation of the Basin reflects the patterns of arid and semi-arid regions that rely on variable water flows and is also home to many rare and endangered species of plants and animals.
The Lake Eyre Basin Inter-governmental Agreement, signed by the Commonwealth, Queensland and South Australian Governments was signed in 2000 and joined by the Northern Territory Government in June 2004. The agreement ensures consultation and engagement across borders with the Lake Eyre Basin community, scientists and technical advisors to ensure the sustainability of the Lake Eyre Basin river systems. The Lake Eyre Basin Rivers Assessment (LEBRA) is a long-term project delivery of the Lake Eyre Basin Inter-governmental Agreement, which is assessing the condition of the Lake Eyre Basin catchments and their associated rivers, floodplains, overflow channels, lakes and wetlands. LEBRA uses consistent monitoring techniques throughout the Basin providing baseline data for many waterholes, tributaries, and in some cases whole river systems. It provides updated data on fish distribution and abundance from sites previously studied and continuing data for long term monitoring sites.
For over a decade the SA Arid Lands Natural Resources Management Board through Australian Government funding has invested in extensive investigations of the South Australian portion of the Lake Eyre Basin - read more about the LEB catchment projects here.
Kati Thanda - Lake Eyre
Kati-Thanda Lake Eyre is a playa lake (lake with no outlet) and collects surface water flows from the 1,140,000 sq km Lake Eyre Drainage Division and groundwater flows. From the west, Macumba, Arckaringa and Neales Lake flow into Lake Eyre. These normally dry rivers are capable of carrying large volumes of water in times of flood and have dissected the country west of Lake Eyre to form the tableland or breakaway country. Flood events supply the semi-permanent waterholes in the area.
Rivers more likely to fill Kati-Thanda Lake Eyre lie to the east and drain a vast area extending to the highlands of central Queensland: the Warburton (from the Diamantina River) and Cooper Creek. In South Australia, these river systems approach Lake Eyre through the interconnected river courses of the Channel Country. Annual runoff from the Great Dividing Range and Barkley Tablelands of Queensland into the river systems fills some waterholes close to the borders, which are considered permanent. Kati-Thanda Lake Eyre’s lowest parts lie 15.2 m below sea level. Lake Eyre North, 144 kilometres long and 77 kilometres wide, is joined by the narrow Goyder Channel to the much smaller Lake Eyre South. When the lake is in flood it supports major breeding events of the Banded Stilt and Australian Pelican, as well as over 1% of the world populations of Red-necked Avocets, Sharp-tailed Sandpipers, Red-necked Stints, Silver Gulls and Caspian Terns.
- Lake Frome is a large, shallow, unvegetated salt pan, 100 kilometres long and 40 kilometres wide, lying mostly below sea level and having a total surface area of 259,615 hectares. It only rarely fills with brackish water flowing down usually dry creeks in the Northern Flinders Ranges from the west, or exceptional flows down the Strzelecki Creek from the north. The ‘regional geological significance’ of the lake led to it being proclaimed as the Lake Frome Regional Reserve in 1991.
- Lake Torrens is a 5,700 square kilometre 240 km long dry salt that forms part of the same rift valley that includes Spencer Gulf. It has been filled with water only once in the past 150 years, in 1989. The lake supported up to 100,000 breeding Banded Stilts during the major filling event of 1989. It may occasionally support over 1% of the world population of Red-capped Plovers. Cinnamon Quail-thrushes are also common in the area.
- Lake Gairdner, located in the Gawler Ranges, is the fourth largest salt lake in Australia when it is flooded. The lake 160 kilometre long lake has salt over 1.2 metres thick in some places. It has been a site for various land speed record attempts on its salt flats.
In the arid river system, waterholes of varying permanence become the key refuges for aquatic habitat as they endure brief periods of flowing water and prolonged periods of no flow. The larger, permanent sites are critically important for aquatic habitat to resist extended drought phases and enable them to bounce back in the wet phase.
The Cullyamurra and Algebuckina waterholes are the largest in the SA Arid Lands region. Cullyamurra is a permanent waterhole located in the Cooper Creek catchment about 10 kilometres from Innamincka in the far north-east of South Australia and is part of the Innamincka Regional Reserve. Cullyamurra is the most important refuge waterhole in the Arid Lands region and is approximately 30 metres deep in some sections, supporting up to 12 different native fish species and an important safe haven during the ‘bust’ or drought years. Algebuckina Waterhole is situated on the Neales River about 55 kilometres south-east of Oodnadatta. It is a permanent waterhole that in times of drought, long after other waterholes have become dry, it provides a critical safe haven for fish, birds and other native animals. For tourists travelling the Oodnadatta Track, it is the location of the longest bridge in South Australia which took the Ghan train over the Neales River en route between Adelaide and Darwin.
Rock holes are a surface water feature where water is held in a rock or rocky area. Rock holes are of significant value to Aboriginal people living in arid areas of Australia. They provide a crucial water supply in an otherwise dry landscape where there is little permanent surface water, assisting in travel across the landscape and access to a larger range of resources. In the early years of pastoralism, before the advent of bores and wells, they were also important water resources for stock.