Resuscitating Australia’s Floodplains: Environmental Water

On the left, a thriving wetland. The right, an arid forest.

On the left, a thriving wetland. The right, an arid forest. (Image Credit: Sam Perrin, CC BY-SA 4.0)

I’m standing on the dry side of the Murrumbidgee floodplain in country Australia. I say dry side, because whilst I’m standing on the harsh, dusty platform of soil and desiccated leaves that is pretty standard for this area, 15 metres away there’s a thriving wetland environment. It boasts waterbirds, a flock of emus, thirsty kangaroos, and fish. All that’s separating the wetland and dry land on which I stand is a road, only about half a metre above water level.

The stark difference between the two sites is thanks to the Environmental Water delivery by the Australian government. The program consists of a huge delivery of water upstream from here, which has transformed the opposite side of the road I’m standing astride, and will aim to do the same in many other areas throughout the Murray-Darling Basin, encompassing over 1 million square kilometres in the South-East of the country.

The program is also the reason I’m standing here. I’m currently working with Dr. Keller Kopf of Charles Sturt University, who is out here monitoring fish recruitment along the Murrumbidgee.

“Historically rivers and their floodplains connected much more frequently here.” recounts Keller. “Because we regulate our rivers now, that doesn’t happen unless you have an exceptionally large flood. The environmental water scheme is way to solve that. The national parks and the lakes would have little water in them during such dry periods if they didn’t deliver environmental water.”

A floodplain is the larger area surrounding a river which becomes inundated when a river breaks its banks. Floodplains are important ecosystems thanks to their productivity, both for wildlife and for people. It provides an atypically fertile ground which sustains all sorts of life in the surrounding area. With extreme warming events and the associated mortality rates of the local species increasing, these ecosystems will be crucial in maintaining Australia’s biodiversity, and the program will play a key role in maintaining them.

But a delivery of water this large isn’t without its drawbacks. Keller and recent PhD graduate Daniel Svozil are monitoring the Murumbidgee for fish larvae, in an effort to predict which species will boom in certain areas following the delivery. For anyone who’s familiar with the fish community in this part of Australia, there’s one species that immediately comes to mind – carp.

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These juvenile carp could benefit from the scheme as well, furthering their impact as an invasive species (Image Credit: Sam Perrin, CC BY-SA 2.0)

“The fact is, when the water comes through here, it can create spawning spawning opportunities for invasive carp” says Svozil.

“Australia’s native species need this water too, so we are trying to figure out ways of delivering environmental water to minimise carp spawning”, adds Keller.

So how does the scheme work? The crux is an enormous buyback of water by the government from farmers who had previously purchased licenses for irrigation. In this case, about 90 gigalitres of water has been purchased, and will be released into rivers at regulators along the Murrumbidgee. The regulators were initially put into place to facilitate the transport of water to farmers for irrigation, but they’re now being used by the government to release water for the environment.

The release of the water for the environment will take place over the next year. With any luck, the rich wetlands that stand in stark contrast to the arid soil I’m standing on will become a more regular occurrence throughout the Murray-Darling Basin. The extreme heat brought on by climate change might yet reduce biodiversity further, but in the meantime Australia’s environmental water scheme is providing some welcome relief to a dry part of the country.

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