Great Artesian Basin

The Great Artesian Basin (GAB) of Australia is the largest and deepest artesian basin in the world, covering over 1,700,000 square kilometres (660,000 sq mi). It has water that ranges in temperature from 30 to 100 °C (86 to 212 °F). This basin is very important because it is the only source of fresh water for many places in inland Australia.

The basin stretches across 22% of the Australian continent. It includes most of Queensland, the south-east corner of the Northern Territory, north-eastern South Australia, and northern New South Wales. In some areas, it is as deep as 3,000 metres (9,800 feet) and holds about 64,900 cubic kilometres (15,600 cubic miles) of groundwater. To help manage this important resource, the Great Artesian Basin Coordinating Committee (GABCC) works with different levels of government and community groups.

Physiography

The Great Artesian Basin is one of the special areas in eastern Australia. It includes a smaller area called the Wilcannia Threshold.

The water in the basin is stored in a layer of sandstone formed long ago during the Triassic, Jurassic, and early Cretaceous periods. When much of inland Australia was underwater, layers of rock formed on top of the sandstone, trapping the water inside. The eastern edge of the basin was lifted up when the Great Dividing Range formed, and the western edge was shaped by the Central Eastern Lowlands and the Great Western Plateau.

Most of the water enters the rock from higher ground near the eastern edge, in Queensland and New South Wales, and slowly moves toward the south and west. A smaller amount enters from the western side in arid central Australia, moving south and east through the sandstone. The water leaves through springs and seeps, mostly in the southern part of the basin. The groundwater ranges from several thousand years old in the north to nearly 2 million years old in the southwest.

Before Europeans arrived, the basin's water flowed through springs, supporting Aboriginal communities and trade routes. After Europeans came, the water helped exploration and communication across Australia. It became vital for cattle stations, irrigation, and daily use in rural areas. To get the water, deep holes called boreholes are drilled, and the water often comes up without needing pumps.

The basin's water allowed people to settle in areas far from rivers in inland New South Wales, Queensland, and South Australia. Europeans found the water in 1878 near Bourke. Today, water extraction is much higher than the natural refill rate, causing problems like dried-up springs and wasted water. Efforts are being made to manage this better. The basin also supplies water to a geothermal power station at Birdsville, where hot water helps produce electricity and provides drinking water for the town.

Whole of Basin management

The Great Artesian Basin is located in parts of Queensland, New South Wales, South Australia, and the Northern Territory. Each area has its own rules and ways of managing resources. In 2020, the Australian government Department of Climate Change, Energy, the Environment and Water created a plan to help manage the basin. This plan was made with help from local governments, community groups, and public feedback.

There is also a group called the Great Artesian Basin Coordinating Committee (GABCC). This group gives advice to leaders from different governments about how to take care of the basin. The committee includes people from government agencies, community members, and representatives from different sectors.

Environmental concerns

In 2011, a program on Australian television talked about worries that taking water out and adding harmful chemicals could hurt the Great Artesian Basin. This is because of a process called coal seam gas extraction.

One time in 2009, a company connecting water to coal underground may have let out a harmful chemical into the Basin. The company did not tell anyone about the problem for over a year.

Many chemicals are used in this process, and some have been found in the water at levels that are not safe. This can harm plants, animals, and people who depend on this water, especially during dry times.

In 2024, a plan to put carbon dioxide into the Basin was stopped because it could make the water unsafe by releasing metals into it.