Snowy River high-flow environmental releases begin mid year
Eight planned high-flow environmental water releases from Jindabyne Dam into the Snowy River will be rolled out between June and November this year.
The releases for the 2024/25 water year have been organised in close consultation with the NSW Department of Climate Change, Energy, the Environment and Water, the Snowy Advisory Committee and Snowy Hydro.
The plan includes frequent smaller releases and eight large high-flow releases that will be more than 2,500 ML a day.
A flushing flow is planned in October, which will be delivered if Jindabyne Dam water levels are high enough to enable delivery of flows via the spillway gates. If water levels are insufficient to achieve this, a peak flow as low as 5,000 ML/day will be released via the cone valves.
Whilst the department is committed to informing the public of high-flow releases, the plan may change subject to weather, operational and environmental conditions.
The public should check the DCCEEW website for any changes closer to each of the planned events at Snowy River increased flows.
The high-flow events are generally released at midnight, with a constant flow rate for 24 hours. Five of the high flow release events will include a higher peak flow rate over 8 hours from 8am to 4pm.
The high-flow releases include:
- 27 June 2024 - daily flow of 2,977 megalitres per day (ML/d) over 24 hours, with equivalent peak flow 4,006 ML/d for eight hours from 8:00 am to 4:00 pm
- 21 August 2024 - daily flow of 3,549 ML/d over 24 hours, with equivalent peak flow 4,916 ML/d for eight hours from 8:00 am to 4:00 pm
- 28 August 2024 - daily peak flow of 4,935 ML/d over 24 hours
- 19 September 2024 - daily peak flow of 3,135 ML/d over 24 hours
- 3 October 2024 - daily flow of 3,917 ML/d over 24 hours, with equivalent peak flow 4,787 ML/d for eight hours from 8:00 am to 4:00 pm
- 14 October 2024 - daily peak flow of 2,932 ML/d over 24 hours
- 23 October 2024 - daily flow of 5,596 ML/d over 24 hours with equivalent peak flow of 9,563 ML/d for eight hours from 8am to4 pm if Jindabyne Dam levels are high enough to enable delivery via the spillway. Alternatively, a peak flow which may be as low as 5,000 ML/d will be delivered.
- 24 October 2024 - daily peak flow of 2,575 ML/d over 24 hours. If dam levels are not high enough to allow the peak delivery on 23 October, a daily flow of 3,525 ML/d will be delivered on 24 October over 24 hours
- 21 November 2024 - daily flow of 2,410 ML/d over 24 hours, with equivalent peak flow 3,837 ML/d for eight hours from 8:00 am to 4:00 pm
Environmental water releases to the Snowy River are mandated under the Snowy Water Inquiry Outcomes Implementation Deed 2002, a tri-government agreement between the Australian, New South Wales and Victorian Governments, to achieve improvements in Snowy River health.
The Snowy Advisory Committee brings together local knowledge and expert advice on the timing and annual pattern of environmental water releases to the Snowy River.
Further information about Snowy River environmental releases go to:
QUOTES ATTRIBUTABLE TO: NSW Department of Climate Change, Energy, the Environment and Water Director Asset Management and Performance, Aurelio Lindaya:
“The first of eight planned high-flow environmental water releases to the Snowy River will commence on 27 June, and the last will occur in November this year.
“If water levels are high enough in the Jindabyne Dam to enable a flushing flow delivery via the spillway, the largest event planned in this year’s series will take place on 23 October. It will have a daily flow of 5,596 megalitres and a planned peak flow equivalent to 9,563 ML a day 8am to 4pm. If water levels in the dam are not high enough to deliver a flushing flow, a lesser volume will be delivered via the cone valves.
“The release of environmental water into the Snowy River over a series of high-flow events has been successfully trialled over several years.
“The timing and duration of high-flow events does vary year to year based on inflow sequences to the Snowy catchment.
“This year’s high-flow water releases are spread across winter and spring, reflecting the natural timing of likely high-flow events.
“This flow pattern includes daily and seasonal flow variability which assists the river to re-establish stream function, including scouring of sediment to improve in-stream habitat.
“The results from previous studies show the Snowy River is responding well to these seasonal high-flow events and this continuing approach has received input and support this year from the Snowy Advisory Committee.
‘These releases will help promote channel function within the Snowy River remnant bed, wet the riparian zone and promote the establishment of aquatic vegetation providing important habitat for water dependant animals including native fish, water bugs, frogs and platypus.
“The high-flow releases will have the greatest impact on river levels immediately below the Jindabyne Dam wall, but increased flows may be observed along the full length of the Snowy River.
“For the high-flow releases, during the days leading up to and following the release, will have intermediate flows to create a more natural flow release pattern that maximises ecological benefits. This means the river level will also be higher than normal on either side of the planned releases.
"Natural system inflows downstream of the dam may also contribute to higher river levels than predicted.
”Downstream landholders and visitors to the area are 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.
“In addition to the high-flow releases, smaller flow releases below 2,500 ML a day will also be made throughout the year.
“For the first time this year, we are trialling a more flexible approach to delivering these smaller flows.
“This is an outcome of the Snowy Water Licence Review, to better support river health including water dependant plants, animals and native fish.
“This adaptive management approach is commonly applied in other rivers’ environmental watering programs. This means that for releases under 2,500 ML a day, the volume and timing of planned releases may change without notice.”
