Upper Murrumbidgee High-Flow Environmental Releases

Environmental water releases from Tantangara Dam into the upper Murrumbidgee River for the 2024/25 water year have been organised by NSW Department of Climate Change, Energy and Environment and Water in Close consultation with the Snowy Advisory Committee and Snowy Hydro.

The plan includes frequent small releases, two moderate releases in excess of 1,000ML/day with one large high-flow release of 1,500ML/day on September 24 starting at midday.

While the department works hard to inform the public of high-flow releases ahead of time, the plan may change subject to weather, operational and enviornmental conditions.

Director Asset Management and Performance at DCCEEW, Aurelio Lindaya said the planned high-flow release from Tantangara Dam into the upper Murrumbidgee River would be in the order of 1,500 megalitres per day.

“The high flow event is designed to maximise the ecological benefits for the river,” Ms Lindaya

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

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

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

“The high-flow release will have the greatest impact on river levels from immediately below Tatangara Dam wall to Yaouk.

“The river will be higher than normal on either side of the release.

“Natural system flows downstream of the dam may also contribute to flows, resulting in higher river levels than predicted.

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

“Whilst we endeavour to make release consistent with the planned date, it may be necessary to modify or cancel flow in the lead-up to the event because of environmental, weather or operational conditions.

“We encourage the public to check our website for any changes closer to the event.

“In addition to the large flow release, frequent moderate and smaller releases will be made throughout the year.

“The planned flow pattern includes a high degree of daily and seasonal flow variability which assists the river to re-establish stream function, including flushing fine sediment and improving in-stream habitat.

“High-flow environmental water releases improve the health of the upper Murrumbidgee River by flushing sediment, clearing vegetation that encroaches into the channel, providing opportunities for fish and other native animals to move and wetting and filling riverside wetland areas.

“Extraction of water during environmental flow events may be subject to temporary water restriction orders which is why 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.”

• Topics:

• Water
• The Environment