Environmental watering in the Murrumbidgee River
More than 160 gigalitres of environmental water was released into the Murrumbidgee River in New South Wales in June 2011.
Simon Banks manages the use of Commonwealth environmental water in the southern Murray-Darling Basin.
In this interview, Simon explains how the increased flows will benefit wetlands downstream and improve water quality through the Murray-Darling Basin.
Interviewee: Simon Banks
Interviewer: Commonwealth environmental water was released into the Murrumbidgee River from Burrinjuck Dam in New South Wales in June 2011. Simon Banks manages the use of Commonwealth environmental water in the southern Murray-Darling Basin.
Simon, here we can see the environmental water being released from the dam. How much water are we looking at here?
Simon: The releases that you can see is at about 900 megalitres per hour, or over the course of a day about 20 gigs per day. The Commonwealth provided 109 gigalitres to an event of 160 gigalitres with a number of other delivery partners contributing water.
Interviewer: Okay. Well, it certainly looks like a lot of water from the air there. What's the point of releasing so much environmental water at once?
Simon: The idea is to mimic a rainfall event that would have happened up in the catchment that now is captured by a dam, and the idea is generating a flow that will fill many billabongs and wetlands and little anabranches through the Murrumbidgee River.
Interviewer: Okay. And how far does that water then go through the river?
Simon: The majority of the water released from the dams flowed all the way along the Murrumbidgee River into the Murray River and down into South Australia and the lower lakes.
Interviewer: And along the way, which wetlands will be benefitting?
Simon: Look, there's hundreds of small wetlands and anabranches and billabongs along the length of the Murrumbidgee River. What we were targeting with this particular flow event was the mid Murrumbidgee wetlands which are in the Narrandera to Hay area.
Interviewer: All right. And we can see one of those wetlands here. Where is this one?
Simon: This is a small privately owned wetland west of Narrandera called Sunshower Lagoon. What we can see here is the rise and fall of the water as the flow pulse went through the system. The footage that we can see is time-lapsed footage over about a three-week period.
Interviewer: What will that extra water coming through that lagoon mean locally for the ecosystem there?
Simon: Look, many of these wetlands and lagoons, like Sunshower Lagoon, received natural floodwater in December, but however the response from the plants and animals was considered to be fairly poor. The extra water will give the seeds in the soil a chance to germinate and the plants to grow creating habitat for fish, frogs and birds.
Interviewer: And how will you be checking how those ecological benefits are playing out over the whole system?
Simon: What we're doing here is we've got Charles Sturt University who are monitoring the ecological response of this event, so the scientists are looking at things like biofilms, which is simply the slime that grows on rocks, frogs, birds and water quality.
Interviewer: And how is it that environmental water improves water quality in the Murray-Darling Basin?
Simon: A flow like this one that goes through the Murrumbidgee River into the Murray and down into the Lower Lakes will benefit the basin as a whole by exporting salt, nutrients and other things that build-up during times of drought, and really this is just one good example of many.
Interviewer: Great. Thanks Simon.
End of Interview.