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Upper Murrumbidgee environmental high flows to commence in July

The first of the three high-flow releases will begin on 10 July, followed by one in August and the final release in September 2023 although the plan may change subject to climatic, operational and environmental conditions.

NSW Department of Planning and Environment Director Asset Management and Performance, Aurelio Lindaya, said the first release will have a peak flow of 1,500 megalitres per day (ML/d) over a 24-hour period.

“The three planned high-flow releases from Tantangara Dam into the Upper Murrumbidgee River will be in the order of 1,500 megalitres per day,” Mr Lindaya said.

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

“The release of environmental water into the Upper Murrumbidgee via a series of high-flow events has been successfully trialled in previous years.

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

“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 natural system inflows downstream of the dam may result in higher river levels than predicted.”

Mr Lindaya said 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.

“Whilst we endeavour to make releases consistent with the planned dates, it may be necessary to modify or cancel flows in the lead up to the event as a result of environmental, climatic or operational conditions. We encourage the public to check our website for any changes closer to the event.”

The planned 2023 high-flow releases are:

Monday, 10 July 2023Daily peak flow of 1,500 ML over 24 hours from midday
Monday, 14 August 2023Daily peak flow of 1,450 ML over 24 hours from midday
Tuesday, 19 September 2022Daily peak flow of 1,500 over 24 hours from midday

The releases will commence at 12 noon 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 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 animals including native fish such as the endangered Macquarie perch, waterbugs, frogs and platypus.

“Extraction of water during environmental flow events will be subject to temporary water restriction orders. I encourage unregulated licence holders in the Murrumbidgee I and II water sources to check our website for further details.

“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.”

Further information about the Upper Murrumbidgee River environmental releases is available at:

The upper reaches of the Murrumbidgee River. Northern Kosciuszko National Park. New South Wales, Australia.
Planned high-flow water for environment releases to the Upper Murrumbidgee River will begin on Monday, 10 July.