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Water in, water out: assessing the future of the Great Artesian Basin

The Great Artesian Basin is huge and ancient underground “water tank” big enough to fill Sydney Harbour 130,000 times. It streches from Cape York down to Dubbo and further west than Coober Pedy and has been providing the only reliable source of fresh water for rural communities in Queensland, New South Wales, South Australia and the Northern Territory since the first bore holes were sunk in the 19th century. But new interactions between industries such as agriculture, mining and the water itself has prompted the big question: how does the Great Artesian Basin really work?

Based on research by CSIRO and Geoscience Australia, the assessment provides a substantial update to knowledge about the Basin, benefiting from improvedtechniques to measure and monitor water movement, and incorporating new methodologies that link a range of “development” and management scenarios. The last assessment of the Basin, which primarily focused on hydrology, was in 1980.

This was a challenging project. Compared to surface water catchments where you can actually see where water is draining, the groundwater systems in the Basin are difficult to visualise, which added complexity to assessing the flow of water.

In fact, the complexity of the geological structures and their role in governing groundwater conditions was one of the big surprises of this assessment.

We had long suspected that faults and ridges in an artesian basin would affect how groundwater moves between aquifers. But we needed to understand how water moves into, out of and around the Great Artesian