Great Artesian Basin

Deep under the ground is a huge pool of water.

This water is trapped in a layer of rock. It sits under a big part of Australia. The water is very old. Some of it is two million years old!

This water is a lifeline for the land. It helps people and animals live in dry places. People drill deep holes to reach it. Sometimes the water is so strong it pushes itself up. This water even helps make power for a town. It is a very special gift from the earth.

The Great Artesian Basin is a huge underground water source. It sits under 22% of Australia. It covers parts of Queensland, New South Wales, South Australia, and the Northern Territory.

This water is held in a sandstone aquifer. An aquifer is a layer of rock that holds water. Long ago, layers of rock covered the sandstone. This trapped the water deep underground. Most water enters from high ground in the east. It flows very slowly toward the south and west. Some water is nearly 2 million years old!

This water is a lifeline for rural areas. People drill boreholes to reach it. The water pressure often pushes the water up. This helps cattle stations and farms. In Birdsville, the water helps make power. It also provides drinking water for the town.

People must care for this water. Some springs have dried up. This can hurt tiny animals that live there. Using coal seam gas can also cause problems. It may release chemicals into the water. Protecting the basin helps keep the land healthy.

The Great Artesian Basin is a huge underground water source in Australia. It is the largest and deepest artesian basin in the world. This water is a vital lifeline for much of inland Australia. It sits under 22% of the Australian continent. This area includes most of Queensland and the south-east corner of the Northern Territory. It also covers parts of New South Wales and North-eastern South Australia.

This water is held inside a layer of sandstone rock. This sandstone was formed a long time ago during the Triassic, Jurassic, and early Cretaceous periods. During those times, layers of marine sedimentary rock covered the sandstone. This acted like a lid to trap the water inside. Most new water enters from high ground near the eastern edge. It flows very slowly toward the south and west. In some areas, the water moves only one to five metres per year.

People first used the water through natural mound springs. These springs supported Aboriginal communities and trade routes long ago. European explorers also used the springs to travel across the land. In 1878, a shallow bore near Bourke produced flowing water. This was a major discovery for people living there. Other bores were found near Barcaldine in 1886 and near Cunnamulla in 1887.

Today, people reach the water by drilling deep boreholes. The pressure from the rocks often pushes the water up without pumps. This water helps cattle stations, farms, and even power stations. For example, a station in Birdsville uses the water for electricity. The water there comes out at 60 degrees Celsius. It provides 25% of the town's electricity needs. However, using too much water can cause problems. In 1915, 1,500 bores provided 130 gigalitres of water every day.

We must be careful to keep this water clean and safe. Some natural springs have dried up because water pressure dropped. This can cause tiny animals to die out. Also, some ways of getting gas can release chemicals into the water. Scientists found things like arsenic and uranium in some areas. In 2024, the Queensland Government even banned a type of carbon storage to protect the basin. Protecting this water helps keep the whole land healthy.

The Great Artesian Basin is the largest and deepest artesian basin on Earth. It covers approximately 22% of the Australian continent. This massive underground system includes most of Queensland and the south-east corner of the Northern Territory. It also extends into north-eastern South Australia and northern New South Wales. This basin is a vital lifeline for rural Australia. It provides the only source of fresh water for much of the inland regions.

The water is stored within a deep layer of sandstone. This sandstone was formed by continental erosion during the Triassic, Jurassic, and early Cretaceous periods. Long ago, much of inland Australia was below sea level. During that time, marine sedimentary rock covered the sandstone. This rock acts as a confining layer, which means it traps the water underneath like a lid. This pressure is what makes the basin "artesian." When a borehole is drilled, the pressure often forces the water to the surface without needing mechanical pumps.

Water enters the system through a process called recharge. Most recharge water enters from relatively high ground near the eastern edge in Queensland and New South Wales. From there, it flows very gradually toward the south and west. A much smaller amount enters along the western margin in arid central Australia. This water moves through the permeable sandstone at a very slow rate. It travels only one to five metres per year. Eventually, the water exits through discharge zones, which include various springs and seeps.

The age of this groundwater varies depending on its location. Scientists use carbon-14 and chlorine-36 measurements along with hydraulic modelling to determine its age. In the northern recharge areas, the water is several thousand years old. In the south-western discharge zones, the water is nearly 2 million years old. This shows how incredibly slow the movement of water is through the rock. Before Europeans arrived, this water emerged naturally through mound springs. These springs, such as the Witjira-Dalhousie Springs in South Australia, supported Aboriginal communities and trade routes. They also sustained many endemic invertebrates, including specific types of molluscs.

European discovery of the flowing water began in 1878 near Bourke. Similar discoveries occurred at Back Creek in 1886 and near Cunnamulla in 1887. These findings allowed for the settlement of thousands of square kilometres of country. This land would have been unavailable for pastoral activities without this water. Today, the basin supports cattle stations, irrigation, and domestic use. It even powers a geothermal power station at Birdsville. At Birdsville, the water emerges at 60 degrees Celsius. This provides 25% of the town's electricity needs and serves as their drinking water.

However, extracting water from the basin is similar to a mining operation. The rate of recharge is much lower than the current extraction rates. In 1915, 1,500 bores provided 130 gigalitres of water per day. Today, the total output has dropped to 40 gigalitres per day. This includes nearly 2,000 freely-flowing bores and over 9,000 that require mechanical power. Many bores are unregulated or abandoned, which leads to significant water wastage. This drop in pressure has caused some mound springs to dry up. This loss of water can lead to the extinction of certain invertebrate species.

Environmental concerns regarding the basin are significant. In 2011, reports revealed concerns about depletion and chemical damage from coal seam gas extraction. In 2009, a process called hydraulic fracturing, or "fracking," at the Myrtle 3 well connected an aquifer to a coal seam. This incident involved the release of potentially toxic chemicals. Scientists have found levels of lead, aluminium, arsenic, barium, boron, nickel, and uranium that exceed recommended limits in some contaminated groundwater. Additionally, there were concerns about injecting carbon dioxide into the basin. Experts warned this could increase water acidity and dissolve rock, releasing heavy metals. Consequently, the Queensland Government banned carbon capture and storage in the basin in May 2024.

Managing such a massive resource requires cooperation across many different borders. The basin underlies parts of Queensland, New South Wales, South Australia, and the Northern Territory. Each area operates under different laws and management approaches. To help coordinate this, the Great Artesian Basin Coordinating Committee (GABCC) was formed. The GABCC provides advice to government ministers from various levels. It helps coordinate activity between community organisations and government agencies. In 2020, the Australian government published a Strategic Management Plan to help manage these resources sustainably for the future.