About Snowy montane increased flows
The Snowy Water Inquiry Outcomes Implementation Deed (SWIOID) provides for environmental releases into a number of high altitude (montane) rivers whose flows are significantly affected by the operation of the Snowy Scheme. The Snowy montane rivers are:
- the Snowy River above Jindabyne Dam
- the Goodradigbee River
- the Murrumbidgee River below Tantangara Dam
- the Geehi River.
Read more about the legislative context and the background to the environmental reforms and water recovery achieved through the Snowy Water Infinitive.
Environmental water priorities
The Snowy Montane River Increased Flows (SMRIF) program is managed by the Department of Planning and Environment - Environment and Heritage Group (DPE EHG), in consultation with the Snowy Advisory Committee.
You can find an explanation of the SMRIF program on the DPE EHG website.
You can also fine detailed information on annual priorities, including the ‘Annual Plan for the Snowy and Montane Rivers Increased flows’ at the DPE EHG website.
Annual targets for the 2023-24 water year
| Increased flows | Release location | SWIOID annual target (GL) | Adjusted implementation annual target (GL) | 2023-24 annual volume |
|---|---|---|---|---|
| Murrumbidgee River at Tantangara | Tantangara Dam | 27 | 27 | 40.8 |
| Goodradigbee River | Goodradigbee Weir | 12 | 12 | 7 |
| Geehi River | Middle Creek Weir Strzelecki Creek Weir | 20 | 22.7 | 22.7 |
| Snowy River - Island Bend | Toolbar Creek Diggers Creek Weir | 20 | 18.9 | 18.9 |
| Snowy River - Perisher Range | Falls Creek Weir and minor diversion structures | 30 | 3.4 | 3.4 |
Upper Murrumbidgee River increased flows
The Snowy River Increased Flows program is managed by DPE EHG, in consultation with the Snowy Advisory Committee, who determine annual environmental water priorities for the Snowy Montane Rivers and design a flow regime with the available water to achieve these priorities.
Find detailed information on annual priorities, including the ‘Annual Plan for the Snowy and Montane Rivers Increased flows’ on the DPE EHG website
Similar to the Snowy River, when there is sufficient environmental water available, a modified ‘flow scaling’ approach is applied to the Murrumbidgee River to assist in providing natural seasonality and daily variability. Higher flows improve river health and physical condition of the in-stream habitat by scouring and transporting fine sediment (i.e. primarily, sand, silt and clay).
2023–2024 water year
A total of 40,755 megalitres (ML) of environmental water will be released to the Upper Murrumbidgee River below Tantangara Dam during the 2023–24 Snowy water year (from May 2022 to April 2023).
The Snowy and Montane River Increased Flows (SMRIF) release pattern has been designed to include three high-flow events from Tantangara Dam into the Upper Murrumbidgee River. These high-flow releases are designed to more closely mimic the natural characteristics of the Murrumbidgee River, including snowmelt and ‘freshes’ that occurred before the construction of the Snowy Mountains Scheme.
The pattern will also include a series of smaller releases, along with days of no flow. There will be 12 periods (totalling 94 days) where no environmental flow will be released from Tantangara, as there is insufficient water available to maintain the flow regime for every day of the year that includes multiple high peaks. During this time, Snowy Hydro Limited is required to make releases to maintain flows at or above 32 ML/day at Mittagang Crossing, if tributary flows do not provide this level of flow.
The three planned high-flow releases for the 2023-24 water year are shown in the table below.
| Release date | Release peak |
|---|---|
| Monday 10 to Wednesday 12 July | 1,500 ML/day at midday on Monday 10 July 2023 |
| Monday 14 to Wednesday 16 August | 1,450 ML/day at midday on Monday 14 August 2023 |
| Wednesday 20 to Friday 22 September | 1,500 ML/day at midday on Wednesday 20 September 2023 |
Note: Dates and volumes of these high-flows may change subject to environmental, climatic or operational conditions. A series of smaller release will also be made.
Read the overview of the plan for this year in the media release: Upper Murrumbidgee environmental high flows to commence in July
More detail is available in the Snowy Montane Rivers Increased Flows - Operations Plan 2023-24 (PDF, 255.83 KB)
Temporary water restrictions
As done in the 2022-23 water year, temporary water restrictions will continue to be implemented throughout the 2023-24 water year to prevent extraction of environmental flows. This will apply to unregulated licence holders in the Murrumbidgee I and II water sources.
More information is available on the temporary water restrictions () webpage.
To comply with the restriction, unregulated licence holders in the Murrumbidgee I and II must not pump if flows at the relevant gauge are below the temporarily raised access thresholds published in the order for that day.
Safe management of high flows into the Upper Murrumbidgee
The department works with Snowy Hydro and other relevant agencies to ensure the safety management of high flow releases from Tantangara dam into the Upper Murrumbidgee river. The Snowy Montane Rivers Increased Flows – Safety Management Plan 2022-2027 (PDF, 1137.67 KB) details the processes that are followed. This Plan is reviewed annual for currency.
Rising river alerts for 2023-24 water year
The department will publish ‘rising river alerts’ below and issue them to relevant media organisations several days prior to each of the three high-flow events.