Snowy River increased flows
In determining how to use the environmental water recovered for the Snowy River through the Snowy Water Initiative, the New South Wales, Victorian and Commonwealth governments jointly agreed that ecological objectives would be achieved by storing and then releasing sufficient volumes to provide annual flushing flows. These high flows facilitate the improvement in the physical condition of the in-stream habitat by scouring and transporting fine sediment (i.e. primarily, sand, silt and clay). Meeting ecological objectives was identified as a high priority during the Snowy Water Inquiry. High flushing flows are important to improve river health. It is expected that as the river physically responds over time to the higher flows, the focus of the recovery process will transition to meet other ecological objectives.
2021–2022 Water year
A total of 209,577 megalitres of environmental water will be released to the Snowy River below Jindabyne Dam during the 2021–22 water year. During winter and spring, the water will be released under nine separate high-flow events.
The daily flow for each of these events will be above 2,000 megalitres per day between 21 June and 9 November 2021. This will include five eight-hour peaks above 4,000 megalitres per day.
|Release date||Daily and peak flow (megalitres/day)|
|Monday 21 June 2021||Daily peak flow of 2,431 megalitres per day (ML/d), with equivalent peak flow 4,107 ML/d for eight hours*|
|Tuesday 6 July 2021||Daily peak flow of 3,900 ML/d, with equivalent peak flow 5,000 ML/d for eight hours*|
|Monday 23 August 2021||Daily peak flow of 2,080 ML/d over 24 hours|
|Thursday 26 August 2021||Daily peak flow of 5,000 ML/d over 24 hours|
|Thursday 23 September 2021||Daily peak flow of 2,742 ML/d over 24 hours|
|Thursday 30 September 2021||Daily peak flow of 2,218 ML/d over 24 hours|
|Wednesday 6 October 2021||Daily peak flow of 5,516 ML/d, with equivalent eight-hour peak flow 10,362 ML/d for eight hours* (largest flow)|
|Tuesday 19 October 2021||Daily peak flow of 3,871 ML/d, with equivalent eight-hour peak flow 4,699 ML/d for eight hours*|
|Tuesday 9 November 2021||Daily peak flow of 2,831 ML/d, with equivalent eight-hour peak flow 4,263 ML/d for eight hours*|
* These high flow events are expressed as an equivalent flow rate. The peak flow rate will occur for eight hours so as to (i) mimic the flashy hydrology of the Snowy and to (ii) promote habitat improvement. These will occur from 8.00 am to 4.00 pm.
The largest peak flow on 6 October 2021 may need to be moved back to later in October, subject to having enough water in Jindabyne Dam to provide adequate flow releases.
The releases to the Snowy River will be above 2,000 megalitres per 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 2,000 megalitres per day to maximise the ecological benefits for the river.
The department will issue 'rising river alerts' to relevant media organisations several days prior to each of the nine high-flow events.