Native fish spawning, recruitment and movement, along with endangered waterbirds and frogs, were the focus of managed environmental flows in 2024–25.
Key outcomes
Under average rainfall and flow conditions, environmental water managers worked with partner agencies and stakeholders to coordinate the delivery of water for the environment to:
- create flow conditions to support golden perch recruitment in the lower Murrumbidgee River and connected Lowbidgee lakes
- maintain distribution of the endangered southern bell frog and Australasian bittern in key areas of the Lowbidgee floodplain
- improve fish movement by managing several opportunistic fish pulses, which incorporated the removal of the 3 lower Murrumbidgee weirs.
Catchment conditions
During 2024–25, the condition of wetlands varied considerably across the catchment. The Murrumbidgee system experienced moderate to dry conditions and general security allocations reached their highest at 68% in May 2025.
The unavailability of infrastructure constrained the scale of floodplain watering in the Lowbidgee, for example in Yanga and Gayini. Instead, environmental water use focussed on in-channel events to benefit native fish breeding and movement opportunities within the Murrumbidgee River.
Partnering with Aboriginal peoples
Water for Country represents the planning and delivery of environmental water by the Department of Climate Change, Energy, the Environment and Water in collaboration with Aboriginal people across New South Wales. This work continues to progress, supporting ecological outcomes while also protecting and revitalising cultural places, values and interests.
In the 2024–25 water year, environmental water managers:
- worked collaboratively with Nari Nari Tribal Council to deliver cultural and environmental outcomes throughout the Gayini wetlands through deliveries of water for the environment
- worked closely with Mutthi Mutthi to deliver multiple instream flow events, focussed on native fish breeding, followed by connectivity flows to allow fish to move along the lower half of the regulated Murrumbidgee River and into the Murray system
- worked closely with Wiradjuri to partner the delivery of Cultural Access Licence water with water for the environment at several Murrumbidgee Irrigation Area wetland sites
- attended and contributed to gatherings of Traditional Owners of the Murrumbidgee, supported by the Commonwealth Environmental Water Holder and facilitated by the Murray Lower Darling Rivers Indigenous Nations. Discussions centred on addressing issues and concerns collaboratively for the benefit of Country. A key focus was native fish movement, with acknowledgement of improvements in the mid-Murrumbidgee. Specific strategies and actions were discussed to enhance native fish movement into the lower system and continue to work collaboratively.
Watering aims
Under predicted wet to very wet weather and water availability, the Murrumbidgee Environmental Water Advisory Group developed its annual environmental water priorities in the Murrumbidgee catchment 2024–25.
Aims for the use of water for the environment were to:
- provide foraging and breeding habitat for waterbirds, including threatened species, in the Lowbidgee
- provide stable Murrumbidgee River and Yanco Creek flows during the Murray cod and trout cod nesting season to maximise nesting success
- maintain native fish, turtle and southern bell frog core habitat areas
- increase river connectivity with the Lowbidgee lakes and maximise fish passage by slowing rates of recession after dam releases.
When opportunities presented, environmental water managers used adaptive management strategies to maintain river functions and enhance opportunities for plants and animals to breed, move and thrive.
Regulated flow conditions were ongoing almost throughout the year, due to average to below average rainfall, with only 10 days of supplementary water access announced in December. By comparison, in flood years supplementary water access can often extend over many months. The floodplain wetlands of Yanga National Park and the mid-Murrumbidgee progressively dried out, except for some low-lying sites which were connected to the river during the large fish pulse in spring.
In the Lowbidgee, the Gayini (Nimmie-Caira) wetlands, Western Lakes and the central section of the North Redbank wetlands received water for the environment.
Water delivery
This table and chart provide a summary of 385,965 megalitres of water for the environment delivered in the Murrumbidgee catchment during the 2024–25 watering year.
Figures were accurate at the date of publishing but may be adjusted. Watering event numbers in the table and chart relate to location numbers marked on the map.
Notes: CEW = Commonwealth licensed environmental water; EWA = environmental water allowance accrued under the Water Sharing Plan; NSW = NSW licensed environmental water; Other = landholder; TLM = The Living Murray.
| Watering event number | Event name | Outcomes | Start date | Finish date |
|---|---|---|---|---|
| 1 | North Redbank Wetland Complex | Water birds, native vegetation | 5 August 2024 | 1 March 2025 |
| 2 | Murrumbidgee Irrigation Area Wetlands | Water birds, native vegetation | 23 August 2024 | 1 May 2026 |
| 3 | Coonancoocabil Lagoon Complex | Native fish, native vegetation | 26 August 2024 | 3 December 2024 |
| 4 | Western Lakes Complex | Water birds, native vegetation | 6 September 2024 | 14 October 2024 |
| 5 | Gayini Nimmie-Caira | Water birds, native vegetation | 18 September 2024 | 15 April 2025 |
| 6 | Yanco, Billabong, Colombo and Forest creeks | Water birds, native vegetation, connectivity | 22 September 2024 | 28 February 2025 |
| 7 | Murrumbidgee Fish Pulse | Native fish | 4 October 2024 | 20 May 2025 |
| 8 | Middle Wetland Old Coree | Native vegetation | 13 November 2024 | 29 May 2025 |
| 9 | Coleambally Irrigation Area Wetlands | 19 November 2024 | 4 November 2025 | |
| 10 | Toogimbie IPA Wetlands | Waterbirds, native vegetation | 24 November 2024 | 8 February 2026 |
| 11 | Sandy Creek | Water birds, native vegetation, connectivity | 17 December 2024 | 10 October 2025 |
Outcomes
In 2024–25, environmental water managers worked collaboratively with the Nari Nari Tribal Council, and the Commonwealth Environmental Water Holder to deliver 89 gigalitres of water for the environment across the Gayini (Nimmie-Caira) wetlands. This watering event started in mid-September and extended through to mid-April. The extended duration was necessary to top up native fish and turtle refuge sites at Tala Lake, Tala Creek and Waugorah Lagoon and to support Australasian bittern breeding and fledging.
Working closely with the Commonwealth Environmental Water Holder, Murray–Darling Basin Authority and WaterNSW, 192 gigalitres of Commonwealth Environmental Water Holder, The Living Murray project and New South Wales water for the environment was used to successfully recruit golden perch in Yanga and Tala Lakes.
Throughout spring, summer and autumn, several fish pulses were either created or protected to maximise fish movement and floodplain connectivity outcomes for native fish. Elevated base flows were also provided in the lower reaches of the river to enhance native fish habitat during the hotter months.
In partnership with Murrumbidgee Irrigation, NSW National Parks and Wildlife Services, NSW Crown Lands, Murray–Darling Wetland Working Group and the Commonwealth Environmental Water Holder, 4.6 gigalitres of Commonwealth, New South Wales and Murray–Darling Wetland Working Group environmental water was delivered to prioritised wetlands across the Murrumbidgee Irrigation Area. These wetlands provided habitat for threatened species including Australasian bitterns, Australian painted snipe and large numbers of brolgas.
Case study: golden perch thriving in Lowbidgee Lakes
Fish pulse environmental flows timed to occur during the water temperature trigger for golden perch spawning and the end of the Murray cod nesting period, have achieved numerous intended outcomes.
Monitoring conducted during the spring fish pulse flows detected larval Murray cod and golden perch drifting into Tala and Yanga lakes. Subsequent sampling in autumn 2025 detected young golden perch, which had grown out to juvenile fish in the productive and food-rich lake environments.
In addition to stimulating fish breeding, the inflows of environmental water increased the water level in Tala Lake by 70 cm ensuring a good depth to support fish throughout the summer. Tala Lake levels were further maintained in autumn by environmental flows from the vast Gayini floodplain to the east, which connected with and topped up the depleted lake level by 20 cm.
As the next generation of golden perch thrive in the Lowbidgee lakes, environmental water managers are planning for future native fish pulses and lake re-connection flows.
Mutthi Mutthi Elder and member of the Murrumbidgee Environmental Water Advisory Group, Patsy Winch, described the fish breeding outcomes as a fantastic achievement for all involved.
Environmental water managers and monitoring staff meet weekly to discuss options to build on these outcomes, further increase native fish numbers and create opportunities for fish movement between the river and the lakes again next season.
