Murray's past could unlock climate future

In a study published in the Scientific Reports journal on Wednesday, a team of researchers looked at sediment from the lower Murray River that would have formed a large prehistoric lake.

The scientists believe the research provides an invaluable long-term record of basin flows from thousands of years ago when sea levels were about two metres higher than today.

The University of Newcastle's Hannah Power said the findings were key to effective management of the basin under climate change.

She said scientists wanted to determine the impact of higher sea levels and more intense droughts and floods on river systems.

Dr Power said looking back 5000 to 8000 years - a period known as the Holocene Highstand - was one way to look at higher sea levels.

"What we have discovered has the potential to provide an in-depth climate history for the Murray-Darling Basin over the last 8000 years," she said.

Dr Power said the modern-day Murray River was a managed system with artificial barriers to keep the water in the lower lakes fresh and provide for irrigation.

"While the way we manage this system may not change any time in the near future, our research gives us an insight into what could happen under future sea level rise should we decide to remove the barrages," she said.

University of Sydney associate professor Thomas Hubble said the work could help with a reliable and detailed climate history for Australia's most important river basin.

"This is a key piece of knowledge to ensure we manage our biggest river basin as effectively as possible," he said.

The investigation was led by recently completed PhD student Anna Helfensdorfer from the School of Geosciences at the University of Sydney.

This work is part of a larger project looking at lower Murray River channel changes over the past 10,000 years.

Australian Associated Press