Hydrogeology of the Great Artesian Basin

Transcript

We would like to respectfully acknowledge the Traditional Owners of the land on which this project takes place, and Elders both past and present. We also recognise those whose ongoing effort to protect and promote Aboriginal and Torres Strait Islander cultures will leave a lasting legacy for future Elders and leaders.

The Hydrogeology of the Great Artesian Basin

Relevance and importance

The Great Artesian Basin is Australia’s largest groundwater aquifer, holding 65 million gigalitres of water.

A spiritually significant water source for First Nations people, it is critical to the survival of more than 80 regional Queensland towns.

We need to continue to manage this resource well, to ensure it survives into the future.

Usage and reliance

About 315,000 megalitres of groundwater is extracted from the Great Artesian Basin in Queensland every year to supply livestock, agriculture, mining, tourism, towns and households.

Many unique ecosystems, with species found nowhere else, depend on its spring waters. Without it, they would perish in an arid environment.

Formation

Between 65 to 200 million years ago, inland Australia was at times, underwater, and coarse and fine grained sediments settled into permeable and impermeable layers called aquifers and aquitards.

Groundwater is confined within the aquifers by the impermeable aquitards.

Location and boundaries

The Great Artesian Basin is made up of several sedimentary basins.

The Eromanga Basin underlies most of the Lake Eyre Basin catchments in Queensland.

Reliance on recharge zones and zone locations

Water enters the basin aquifers generally through intake beds along the Great Dividing Range and eastern Carpentaria, and takes thousands of years to flow west under great pressure.

Geological structure impacts on water flow

Geological faults can disrupt the flow of water through the aquifer.

Water table and pressure

Groundwater generally flows from high to low elevation due to gravity, and from high to low pressure due to hydrostatic forces.

Bores and springs

When groundwater pressure is high enough, water can flow freely to the surface, through artificial bores and naturally occurring fractures.

Impact of extraction

High rates of water extraction can cause groundwater pressure to drop. This can impact groundwater accessibility and reduce water flows from artesian springs to surrounding ecosystems.

The key to reliability

To maintain and restore reliable artesian pressure, we have already significantly controlled artificial outflows, minimised the use of open bore-drains, and repaired degraded bore infrastructure, but continued good management, sustainable water use and research must continue.

The importance of knowledge and research

With the growing importance of this water source to the region, we must continue to improve our understanding of the hydrology and groundwater flow dynamics of the Great Artesian Basin.

With collaborative approach to research, modelling, mapping decision making and management of its use, we can look after this valuable resource and ensure reliable groundwater for the region, well into our future.

Call to action

To find out more, visit: wetlandinfo.des.qld.gov.au

Last updated: 17 July 2020