WaterNSW is warning landholders on the Tumut River to be alert for river height fluctuations as a result of releases from Blowering Dam in the coming days and weeks.
With the Bureau of Meteorology (BoM) forecasting a higher likelihood of wet weather ahead, the dam catchment already saturated and the storage also receiving inflow from electricity generation upstream from Snowy Hydro, a future spill cannot be discounted, a WaterNSw spokesperson said.
To manage storage levels in recent months WaterNSW has released large volumes of water from the dam, a spokesperson said, which is currently about 99.6% of capacity and releasing 7000 megalitres per day (ML/day).
In the past month WaterNSW has steadily released more than 260,000 megalitres from the dam to manage storage levels and accommodate inflow from power generation by Snowy Hydro and rainfall.
Operational releases from Blowering are currently capped by channel capacity rule constraints to not exceed a total flow rate of 9300 ML/day at Tumut, including downstream tributary inflows.
Over the past 12 months the La Nina weather pattern has generated more than 1800 gigalitres (GL) of inflow into the dam, which holds 1630 GL when it is 100%.
Tumut River landholder Kevin Malone, who runs a dairy farm on the Tumut Plains, said farmers would bear the brunt of any flooding.
“You have Snowy Hydro and State Water, owned by two different governments, and they both have money in mind,” he said. “We the farmers bear the brunt of it.
“I don’t want to be too negative – since the Snowy Scheme we don’t get the floods we used to and we have water there when we need it, so in some sense I understand we have to take the bad with the good. But the way they manage the dams is at times frustrating.”
He believes more water should have been let out of Blowering earlier.
“You could see something was going to happen months ago,” he said.
“The dam was just too full, putting aside all the long-range forecasts, even in a normal year it was just too full.
“Now with the supposed energy crisis, Snowy Hydro is making an absolute fortune I imagine generating energy.
“It would be nice if some of the profits they’re getting are put into fixing the impacts the high flows will have on the river.”
Tumut River landowners have for decades been dealing with riverbank erosion from the rise and fall of the river to accommodate Blowering Dam releases.
Rocking the riverbank is the only real solution, Mr Malone said, along with planting trees such as weeping willows, to prevent erosion.
He said a flooded river, if it eventuates, would cut off parts of his land and create difficulties moving cattle, as “riverlets” form on his property.
There’ll also be damage to pastures and fences.
He’s unhappy farmers aren’t consulted on the dam’s management.
“It’s challenging enough now with all the mud and water – a flood is the last thing that we want. There’s been no consultation with landholders that I’m aware of,” he said.
“State Water and Snowy Hydro are going to do what they do, it doesn’t really matter what we think.
“That’s been clear for a long time.”
Landholders are advised to monitor release rates and river impacts:
Sign up to the Early Warning Network (EWN) – https://waternsw.com.au/supply/ewn
Visit WaterInsights for dam levels, rainfall totals, dam releases etc – https://waterinsights.waternsw.com.au
o Check the BoM website to receive the latest weather and flood information – http://bom.gov.au/australia/flood
o For emergency information, contact the NSW SES – 132 500 or http://ses.nsw.gov.au