Opening the ecological floodgates

Image of tree and floodplain landscape
The Barmah Floodplain in Victoria is part of the Murray-Darling Basin

Australian scientists say further research is urgently required to quantify the environmental risks and benefits of engineered artificial flooding.

Dr Nick Bond and Dr Stephen Balcombe from Griffith University’s Australian Rivers Institute are among experts seeking solutions to the challenges posed by the need for equitable water allocation and ecological health and sustainability.

Their paper, Ecological risks and opportunities from engineered artificial flooding as a means of achieving environmental flow objectives, has been published in the Ecological Society of America journal Frontiers in Ecology and the Environment.

With input from Griffith University, the University of Melbourne, Charles Darwin University, The University of WA and the Department of Environment and Primary Industries, the paper says human demand for fresh water has led to global reductions in the productivity of floodplain ecosystems.

“In areas facing water stress, engineering solutions are increasingly being used to meet human needs and ecosystem requirements,” it says, adding that infrastructure includes levees, weirs, regulators and pumps to control water levels and delivery.

Despite a likely expansion of engineered flooding to counter water scarcity, scientists warn it does not mimic all the features and consequences of natural flooding. They say it also risks failing to maintain and restore ecosystem processes and river-floodplain connectivity that support diverse and productive riverine ecosystems.

Of particular concern in Australia is the Murray-Darling Basin, an area of more than a million square kilometres spread across four states and almost 15 per cent of the continent.

The basin was devastated by drought from the mid-1990s and through the first decade of the 2000s, forcing the Murray-Darling Basin Authority – through its Living Murray Program — to spend millions on engineering infrastructure to alleviate a desperate situation.

“Our concern is that in the future we may come to over-rely on water management structures originally used as an emergency measure and to complement natural flooding,” says Dr Bond.

“The next drought cycle will be very interesting, with potential consequences for fish and invertebrates, bird and plant life and other ecological processes. That’s why more research is needed.”

Dr Bond says it is pleasing that some of the necessary research to better manage artificial flooding is already underway, but cautions that the ecological importance of natural flooding should not be forgotten.