Sharing the Waters of the Murray-Darling Basin

While the Murray-Darling River system begins in Queensland and wends its way through four states and dozens of Shires and towns, the river itself cares little for our borders and boundaries. Two reports compiled by the Water for a Healthy Country Flagship are making the risky business of planning for the river's future a little clearer.

To a geographer, the Murray-Darling Basin is a single vast and complex system, with little relationship to the political boundaries of Australia's states.

Two reports prepared by the Water for a Healthy Country Flagship for the Murray-Darling Basin Commission (MDBC) take a similarly comprehensive view of the Basin's water resources. The reports go a long way to describing how the Basin functions; the interaction of the dams, rivers, groundwater and wetlands; and the major risks to this vital resource.

Chief Executive of the MDBC, Dr Wendy Craik, says that the member governments of the Commission are committed to improving the environmental and economic sustainability of the Basin. The Living Murray project, for example, is taking practical steps to achieve environmental benefits for six significant ecological assets along the river; and regulation has been introduced to limit the volumes of water which may be diverted from the Basin rivers.

At the same time, the MDBC identified six major risks which it considered needed closer investigation: climate change; the increasing numbers of farm dams; increased groundwater use; the 2003 bushfires; large scale tree planting; and reduced return flow from irrigation.

Any program to maintain and improve such a complex system will only succeed if it is based on good data and a sound understanding of the total system. Dr Mac Kirby and his research team, who prepared the first of the two reports, emphasise they took a 'whole-of-basin' approach.

"A whole-of-basin approach," they say succinctly, "improves accounting."

"A water balance can help improve the estimates of poorly measured components. The requirement that all water entering minus all the water leaving the Basin must equal the change in storage within the Basin can help constrain the estimates of many components of a water balance."

The first report establishes the hydrological picture at the whole-of-basin scale, and describes the most important processes which drive the Basin as a functioning water system: rainfall, evapotranspiration, groundwater, river flows, dams, diversions and barrages, and the effect of water extraction for irrigation.

Groundwater has a particularly important role to play, as it is so closely involved with salinity – the subject of sustained efforts for decades and a threat into the future.

Lead author of the second report Dr Albert van Dijk says that he and his research team examined the six risks and attempted to bring them together, again in a ‘whole-of-basin' approach.

"A risk shouldn't be confused with a foregone conclusion," says Dr van Dijk. "Our understanding of how the risks might impact on the Basin is by no means complete."

The report emphasises that most of the six risks do not act in isolation, but can affect one another. The total impact on river flows cannot be equated to their sum, but may be more or less severe.

There is one risk however which, the report says, affects all the others combined as well as individually. And that is climate change.

Is the Basin climate changing? Yes, says the report, there has been a sustained and statistically unambiguous increase in mean temperatures across the Basin, matching changes in global temperatures. A study in New South Wales has also shown that the frequency of extremely high temperatures has increased since 1957.

This inevitably affects water resources as evaporation rises, rainfall declines, higher water temperatures affect river ecology, and the effects of drought are exacerbated.

Dr van Dijk says that an important element of the two reports has been to identify areas where research is needed.

"We looked specifically at the key knowledge gaps that affect our ability to assess the impact of each of the six risks on future water resources"

The two linked reports are an important tool for the sustainable management of the shared water resources of the Murray-Darling Basin.

More information:

"The Shared Water Resources of the Murray-Darling Basin (part 1)"
"Risks to the Shared Water Resources of the Murray-Darling Basin (part 2)"


Contacts:

Dr Mac Kirby: 02 6246 5921 Mac.Kirby@csiro.au

Dr Albert van Dijk: 02 6246 5780 Albert.VanDijk@csiro.au
 

Update Home

Message from the Director

International recognition for our WRON initiative

Research partnership to protect the Coorong

Sharing the Waters of the Murray-Darling Basin

Interpreting householder preferences to evaluate water supply

Study helps 'water down' community concerns

Designing environmental flows for the Murray

Can domestic bores help save our drinking water?

The Ring of Confidence - Incorporating Uncertainty into Sediment Transportation Models

Community Engagement for the Reef's sake

Snippets

About this email
 

Meet visiting Fellow
from the Water for a Healthy Country Flagship

Meet Dr Bob Ferrier
 

Meet the Flagship's new Science Director

 
Meet Dr Ian Prosser
 

Meet one of our
PhD students

Meet Deborah Reed
 

EARLIER UPDATES 

April 2006

September 2005

April 2005

November 2004
 

The Water for a Healthy Country Flagship is a CSIRO initiative and part of the National Research Flagships program that aims to deliver scientific solutions to advance Australia's most important national objectives. One of the largest scientific initiatives ever mounted in Australia, it aligns closely with the Federal Government's National Research Priorities. The initiative brings together our national research resources to deliver breakthroughs in fields ranging from healthcare to light metals and the environment.

Please feel free to forward it to those in your organisation who would be interested in receiving future newsletters.

If you do not wish to receive this electronic newsletter from the Water for a Healthy Country Flagship, please reply to this message with the word "unsubscribe" in the subject line. Alternatively, please contact editor.healthycountry@csiro.au or telephone us on +61 2 6246 4565 to request the removal of your email address.

This E-Newsletter is a publication of CSIRO. It does not purport to be comprehensive or to render professional advice. All material in this publication is subject to copyright. For permission to reproduce any part or all of an article, please contact the editor.