Mound spring near Lake Eyre South
Natural discharge from the Great Artesian Basin (GAB) feeds a range of springs, including mound springs, mud springs, boggomoss springs, spring pools or groundwater seeps. Water flows from the Basin to more than 600 artesian springs and spring groups. These springs are mostly around the southern, western and northern margins in South Australia and Queensland. The flow into these springs are generally low, from less than 1 litre to about 150 litres per second.
The springs are inextricably woven into stores and histories of Aboriginal people. They sustained early European exploration and settlement where permanent water was scare. With the drilling of bores, artesian waters now sustain communities and industry across almost a quarter of the country in Queensland, New South Wales, South Australia and the Northern Territory.
The biological communities that depend on springs are links to times long past, when central Australia was lush with wetlands. The great drying of inland Australia over millions of years has left many water dependent creatures surviving on in springs. Most other natural water bodies in arid parts of the Basin are dry for part of the year. The isolation of these communities has led to the development of species found nowhere else in the world.
The communities of native species which depend on the natural discharge of groundwater have been declared an endangered ecological community under the Commonwealth Environment Protection and Biodiversity Act 1999. This listing was based on:
- decline in geographic distribution;
- small geographic distribution coupled with demonstrable threat;
- loss or decline of functionally important species;
- reduction in community integrity;
- rate of continuing detrimental change; and
- quantitative analysis showing probability of extinction.
Springs and associated plants and animals are threatened by draw-down of GAB water. They are also under threat by grazing and trampling by livestock and feral animals, mechanical modification of structure (i.e. dam creation) and the introduction of exotic pasture species.