The first of nine planned high-flow environmental water releases during winter and spring to the Snowy River are set to commence in late June, NSW Department of Planning, Industry and Environment Director Water Planning and Implementation, Allan Raine, said today.
'These high-flow water releases are designed to better mimic the natural flow characteristics that are seen in Snowy Mountain rivers, with the aim of improving the long-term health of the iconic Snowy River,' Mr Raine said.
'The release of environmental water into the Snowy River over a series of high-flow events has been successfully trialled over a number of years.
'The prolonged drought conditions resulted in the 2020 environmental water allocations for the Snowy River being some of the lowest since 2011. With wetter conditions and stronger inflows across the southern Murray-Darling Basin the environmental water allocations for 2021 are significantly higher providing an opportunity to have multiple high-flow events.
'This year there are four scheduled releases in winter and five in spring, to reflect the natural timing of likely high-flow events, while the amount of water being released this year is significantly larger than in 2020 which was severely impacted by the drought.
'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 2021 high-flow releases are:
- Monday 21 June 2021 - equivalent peak flow 4,107 megalitres per day (ML/d) for eight hours
- Tuesday 6 July 2021 - equivalent peak flow 5,000 ML/d for eight hours
- Monday 23 August 2021 – daily flow of 2,080 ML/d for 24 hours
- Thursday 26 August 2021 - daily flow 5,000 ML/d for 24 hours
- Thursday 23 September 2021 - daily flow 2,742 ML/d for 24 hours
- Thursday 30 September 2021 - daily flow 2,218 ML/d for 24 hours
- Wednesday 6 October 2021- equivalent peak flow 10,362 ML/d for eight hours (largest flow)
- Tuesday 19 October 2021 - equivalent peak flow 4,699 ML/d for eight hours
- Tuesday 9 November 2021 - equivalent peak flow 4,263 ML/d for eight hours
The high-flow releases to the Snowy River will all be above 2,000 ML/day for 13 days across the nine high-flow events.
For the two October high-flow events there will be days leading up to and/or following that will have flows larger than 2,000ML/d to maximise the ecological benefits for the river including wetting benches and backwaters providing important habitat for frogs and waterbugs.
'This flow pattern includes a higher degree of daily and seasonal flow variability which assists the river to re-establish stream function, including scouring and improve in-stream habitat.'
Mr Raine said the results from previous studies show the Snowy River is responding well to these seasonal high-flow events and this continuing approach had received input this year from the Snowy Advisory Committee.
'This series of winter/spring releases will help to promote channel function within the remnant bed of the Snowy River, wet the riparian zone, promote the establishment of aquatic and riparian vegetation and will provide important habitat for water dependant animals including native fish, waterbugs, frogs and Platypus,' said Mr Raine.
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 to provide advice each year on the timing and annual pattern of release of environmental water to the Snowy River.
