Great Artesian Basin

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Lore & Background

The water of the Great Artesian Basin is held in a sandstone layer laid down by continental erosion of higher ground during the Triassic, Jurassic, and early Cretaceous periods. During a time when much of what is now inland Australia was below sea level in what is now known as the Eromanga Sea, the sandstone was covered by a layer of marine sedimentary rock, which formed a confining layer that trapped water in the sandstone aquifer. The eastern edge of the basin was uplifted when the Great Dividing Range formed. The other side was created from the landforms of the Central Eastern Lowlands and the Great Western Plateau to the west. Most recharge water enters the rock formations from relatively high ground near the eastern edge of the basin (in Queensland and New South Wales) and very gradually flows toward the south and west. A much smaller amount enters along the western margin in arid central Australia, flowing to the south and east through the permeable sandstone, at a rate of one to five metres per year. Discharge water eventually exits through a number of springs and seeps, mostly in the southern part of the basin. The age of the groundwater, determined by carbon-14 and chlorine-36 measurements combined with hydraulic modelling, ranges from several thousand years for the recharge areas in the north to nearly 2 million years in the south-western discharge zones.

Reader's Guide

The Great Artesian Basin is a critical water source for rural Australia, supporting cattle stations, irrigation, livestock, and domestic purposes. Prior to European arrival, its waters discharged through mound springs that sustained endemic invertebrates and supported extensive Aboriginal communities and trade routes. After European arrival, the springs facilitated exploration and the Australian Overland Telegraph Line. European discovery of the basin dates from 1878 when a shallow bore near Bourke produced flowing water. Water extraction from the GAB is essentially a mining operation, with recharge much less than current extraction rates. In 1915, there were 1,500 bores providing 2,000 megalitres per day; today total output has dropped to 1,500 megalitres per day, with many bores unregulated or abandoned, causing water wastage. Many mound springs have dried up due to a drop in water pressure, likely causing extinction of several invertebrate species. The basin also supplies water for the Olympic Dam mine and a geothermal power station at Birdsville. In 2020, the Australian government published the Great Artesian Basin Strategic Management Plan. Environmental concerns include depletion and chemical damage from coal seam gas extraction, with incidents of hydraulic fracturing chemicals entering the aquifer. In May 2024, the Queensland Government rejected a proposal to inject carbon dioxide into the basin and subsequently banned carbon capture and storage using it.

Did You Know?

• The Great Artesian Basin underlies 22% of the Australian continent.
• Groundwater age ranges from several thousand years in the north to nearly 2 million years in the south-western discharge zones.
• In 1915, there were 1,500 bores providing 2,000 megalitres per day; today total output has dropped to 1,500 megalitres per day.
• A 1.2-kilometre-deep bore at Birdsville provides 25% of the town's electricity from geothermal power.
• The Queensland Government rejected a proposal to inject up to 110,000 tonnes of carbon dioxide per year into the basin in May 2024.

Geological Architecture and Water Dynamics

The Great Artesian Basin is one of Earth's most remarkable hydrogeological structures, spanning 1,700,000 square kilometres — roughly 22% of the Australian continent. Its water is locked within a thick sandstone aquifer deposited as continental erosion carried sediment from higher ground during the Triassic, Jurassic, and early Cretaceous periods. A subsequent blanket of marine sedimentary rock sealed the sandstone beneath, forming a natural pressure trap. The eastern boundary was shaped by the tectonic uplift that raised the Great Dividing Range, while the western limits follow the Central Eastern Lowlands and Great Western Plateau. In its deepest reaches the formation plunges to 3,000 metres and holds an estimated 64,900 cubic kilometres of groundwater. Recharge predominantly enters from elevated terrain along the Queensland and New South Wales margins, then creeps southward and westward at one to five metres per year. A smaller fraction seeps in along the arid western edge, travelling south and east. Carbon-14 and chlorine-36 dating, cross-referenced with hydraulic models, reveals that water near the northern recharge zones is only a few thousand years old, whereas water emerging in the south-western discharge springs has been underground for nearly 2 million years.

Indigenous Springs and the European Water Revolution

Long before European settlement, the basin's natural discharge points — mound springs scattered across arid South Australia, including the Witjira-Dalhousie Springs — sustained diverse ecosystems of endemic invertebrates such as molluscs and anchored extensive Aboriginal communities along vital trade routes. When Europeans arrived, these same springs became critical waypoints for explorers crossing the interior and later enabled the construction of the Australian Overland Telegraph Line, which linked south-eastern Australia to Europe for faster communications. The true water revolution came in 1878, when a shallow bore near Bourke in New South Wales unexpectedly produced flowing water. Similar strikes followed at Back Creek east of Barcaldine in 1886 and near Cunnamulla in 1887. These discoveries transformed thousands of square kilometres of riverless country across inland Queensland, New South Wales, and South Australia into viable pastoral land. Boreholes drilled into the sandstone rely on natural pressure to force water to the surface, often eliminating the need for pumps. The basin became the lifeline for cattle stations, irrigation schemes, and domestic water supply across rural Australia, enabling settlement in regions that would otherwise have remained inaccessible for agricultural use.

Extraction, Depletion, and Environmental Cost

In practical terms, drawing water from the Great Artesian Basin functions as a mining operation: recharge rates fall well short of current extraction. In 1915, roughly 1,500 bores delivered 2,000 megalitres per day; today total output has declined to 1,500 megalitres daily, drawn from just under 2,000 freely flowing bores and more than 9,000 that depend on mechanical pumping. A significant number of these bores remain unregulated or simply abandoned, causing considerable wastage — a problem that has persisted for decades. In January 2007 the Commonwealth Government committed additional funding to bring the situation under control, yet the ecological damage has already been severe: many of the ancient mound springs have dried up as water pressure dropped, likely driving several invertebrate species to extinction. The Olympic Dam copper and uranium mine in South Australia is licensed under the 1982 Roxby Downs Indenture Ratification Act to extract up to 42 megalitres daily, with operations expected to continue until approximately 2060. On a more positive note, a 1.2-kilometre-deep bore at Birdsville taps water at 98 degrees Celsius to power a geothermal station supplying 25 percent of the town's electricity, while the cooled water also serves as its drinking supply.

Multi-Jurisdictional Governance and the 2020 Strategic Plan

Because the basin underlies four separate jurisdictions — Queensland, New South Wales, South Australia, and the Northern Territory — no single authority can manage it in isolation. Each state and territory operates under its own legislative framework, policy regime, and resource-management approach, creating a complex patchwork of regulation. To bridge these gaps, the Great Artesian Basin Coordinating Committee (GABCC) was established to coordinate activity across federal, state, territory, and local government levels as well as community organisations. Its membership encompasses every government agency with management responsibilities for a portion of the basin, community representatives nominated by those agencies, and sector representatives. The Committee advises state, territory, and Commonwealth ministers on achieving efficient, effective, and sustainable whole-of-basin resource management. In 2020 the Department of Climate Change, Energy, the Environment and Water published the Great Artesian Basin Strategic Management Plan, prepared jointly with the individual state and territory governments and developed through consultation with the Coordinating Committee, stakeholders, and public feedback. This document represents the most comprehensive attempt to align the disparate regulatory regimes into a coherent, basin-wide strategy.