Sand dunes in the Simpson Desert, covering a river system that is up to 50 million years old.

Credit: Michael Hutchinson/ANU

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SYDNEY: An ancient river system buried 35 metres below the sand dunes Simpson Desert in Central Australia has been revealed by a team of Australian and American researchers.

This network of rivers and streams under the desert can be utilised for its valuable resources such as water in a sustainable way, the researchers said.

"We have gained insight into how the landscape works so we can manage water responsibly," said researcher Michael Hutchinson from the Australian National University in Canberra, a main contributor to the study published in the latest edition of the Australian Journal of Earth Sciences.

Hidden under thick sand dunes

Scientists have always suspected rivers and streams once traversed the Simpson, but the thickness of the overlying dunes and bedrock in this area and limitations in landscape sensing technology have always held research back.

A team from ANU, after more than a decade of work, have conquered the thick overlying dunes and bedrock and developed complex new Digital Elevation Model (ANUDEM) software that successfully mapped the subtle topography that underlies the landscape of today.

The software models how water moves across the surface of the continent. It infers the location of the underground river system by joining the lowest points from ground-level elevation measurements, Hutchinson said.

Vast river system

Using their new software, the team from ANU mapped the course of the rivers buried roughly 35 m under the Simpson Desert for the first time. The rivers are vast, covering hundreds of kilometres, the researchers said.

It is estimated the rivers and streams are some of the oldest in the world, at least 50 million years old, from a time when the desert was greener and wetter than it is today.

The results looked right according to the team, as the underground rivers were mapped where they were expected to be according to current adjoining rivers in the area.

"The ancient drainage systems are thought to have originated in the wet climate of the late Cretaceous, they are that old," Hutchinson said.