Upper Murrumbidgee environmental flows to commence late June

The first of three planned high-flow water for environment releases to the Upper Murrumbidgee River will begin on Thursday 23 June, followed by one in late July and the final release in mid-October 2022.

NSW Department of Planning and Environment Director Asset Management and Performance, Aurelio Lindaya, said the first release will have a peak flow of 1,025 megalitres per day (ML/d) over a 24 hour period.

“The three planned high-flow events taking place over the next five months, are releases from Tantagara Dam into the Upper Murrumbidgee River that will be above 1,000 megalitres per day,” Mr Lindaya said.

“These high-flow events are designed to maximise the ecological benefits for the river.

“The largest event planned in this year’s series will take place on Tuesday 11 October 2022, which will have a daily peak flow of 1,500 ML/d over 24 hours.”

Mr Lindaya said the release of environmental water into the Upper Murrumbidgee via a series of high-flow events has been successfully trialled in previous years including in 2021.

“The timing and duration of high-flow events varies from year to year, based on inflow sequences to the upper Murrumbidgee catchment,” he said.

“This year there will be two winter and one spring water releases, reflecting the natural timing of expected high-flow events.

“The high-flow releases will have the greatest impact on river levels from immediately below Tantangara Dam wall to Yaouk. The river will be higher than normal on either side of the release and inflows may result in higher levels than predicted.”

“Downstream landholders and visitors to the area are being encouraged to make appropriate plans ahead of the water releases, including moving stock or pumps and infrastructure to higher ground and being aware of flows.”

The planned 2022 high-flow releases are:

  • Thursday 23 June 2022 Daily peak flow of 1,025 ML/d over 24 hours
  • Wednesday 27 July 2022 Daily peak flow of 1,300 ML/d over 24 hours
  • Tuesday 11 October 2022 Daily peak flow of 1,500 ML/d over 24 hours

The releases will commence at midday on the day of each planned event and run for 24 hours.

“This flow pattern includes a higher degree of daily and seasonal flow variability which assists the river to re-establish stream function, including flushing fine sediment and improve in-stream habitat,” Mr Lindaya said.

“The results from previous studies show that Snowy montane rivers respond well to these seasonal high-flow events and this continuing approach has received input and support this year from the Snowy Advisory Committee and ecological experts.

“The high-flow releases help promote river functions within the remnant bed of the Upper Murrumbidgee River, wet the riparian zone and promote the establishment of aquatic and riparian vegetation and provide important habitat for water dependant reptiles and animals including native fish, waterbugs, frogs and platypus.”

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