Ancient waterways sustaining Australia's arid zone

08 August 2012

A new National Water Commission report has advanced our understanding of paleovalleys in arid Australia, how they are connected and where they flow.

Palaeovalleys are geologically ancient, buried river valleys that are often relied on in regional Australia to supply water to pastoralists, mines, tourist centres and remote communities.

Groundwater in Australia's arid zone is essential to the sustainability of this vast region and paleovalleys represent the only viable groundwater resource in many areas.

The estimated annual volume of groundwater currently extracted from paleovalleys is more than 200 gigalitres in Western Australia, 14 gigalitres in South Australia and 8 gigalitres in the Northern Territory.

This $4.935 million study conducted by Geoscience Australia was funded under the Raising National Water Standards Program to improve the management of this valuable resource.

"Paleovalley groundwater resources are essential to sustaining mining operations, horticulture, tourist sites, and many thousands of bores on pastoral stations", said Dr Steven Lewis, Geoscience Australia Project Leader for the paleovalley program.

"Prior to this project there was no coordinated investigation at a national-scale to improve our knowledge of paleovalley aquifers. Nor was there a well defined approach for mapping and characterising paleovalley aquifers as prospective water resource targets," Dr Lewis said.

"An accurate account of the water recharge processes is critical to inform decisions on how extraction should be handled to ensure sustainability of the resource."

A key project output was the development of a map showing approximately 200 discrete palaeovalleys in Western Australia, South Australia and the Northern Territory.

"Some of these paleovalleys were larger than the Murray-Darling River system, and we have mapped several that began in the Northern Territory and ran westwards until they eventually flowed into the Indian Ocean," Dr Lewis said.

"In undertaking this work, we also recognised the importance of paleovalleys to the mineral exploration industry, which could utilise naturally occurring groundwater that has up to four times the salinity of sea water."

Although there is scope extracting substantial volumes of groundwater resources across many parts of arid Australia, the National Water Commission points to the need for any future decisions to take into account the principles agreed under the National Water Initiative for the sustainable and economically efficient use of water resources.

For more information or to arrange interviews, please contact: Geoscience Australia 24 hour Media Hotline 1800 882 035

Topic contact: Last updated: October 4, 2013