The Great Artesian Basin is one of the world's largest groundwater resources stretching from beneath the wet tropics of Queensland, the semi arid regions of New South Wales and the outback deserts of South Australia. The Basin is the only reliable water source for some of the drier areas of Australia and has sustained Aboriginal people for thousands of years. This water resource now sustains a wide range of communities, enterprises and industries throughout Australia's remote rural regions.
Most of the water entering the Basin filters down from riverbeds on the western slopes of the Great Dividing Range during periods of rainfall. Most of the Basin's water is of a quality suitable for most uses, including drinking water. As the water moves from the top of the Basin in Queensland towards the base of the Basin in New South Wales and South Australia minerals are absorbed by the water. This influences the water quality within the Basin, with water lower in the Basin containing higher levels of salt than in the top portion of the Basin. Water moves through the Basin very slowly at a rate of 1 to 5 metres a year. It is for this reason that water extracted from the Basin can be millions of years old since it fell as rain on the land surface.
Water emerges naturally from the Basin through cracks in the rock encasing the water, into springs, shallow water tables or into creeks and rivers creating a permanent water source even during dry periods. Most springs and leakages occur on the edges of the Basin where water is close to the surface. The springs of the Basin are home to unique and endangered animals (Endemic Snail (Jardinella sp)) and plants (Salt Pipewort (Eriocaulon carsonii)) that are found nowhere else in the world. Any changes to the water flow or water quality can be detrimental to these ecosystems.
Like many of Australia's natural resources, the GAB faces many natural resource management challenges. New, rapidly evolving industries now compete with traditional pastoral and agricultural users for a share of GAB water. Management of the GAB is complex and requires a great deal of cooperation between five governments, hundreds of communities and the many industries that rely on its water.
GAB Facts and Figures
- The Basin depth ranges from less than 100m at the edges to 3000m at its deepest point.
- The Basin covers a total area of 1.7 million km2, 23% of Australia and is 1300km at its widest point.
- The total volume of water stored in the Basin is estimated at 64,900 million megalitres
- Some of the water in the GAB is up to 2 million years old
- Maximum pressure in the Basin is 1300 kilopascals
- The average temperature of the water is 30-50 degrees but can reach up to 100 degrees at the surface to 130 degrees below the surface.