Wetland vegetation and waterbirds in the Macquarie Marshes and native fish recruitment in the Wambuul – Macquarie and Cudgegong rivers were the focus of managed environmental flows in 2024–25.
Key outcomes
Under moderate weather conditions, environmental water managers worked with partner agencies and stakeholders to coordinate the delivery of water for the environment in response to conditions and environmental demands.
Actions aimed to:
- maintain resilience in core wetland vegetation communities of the Macquarie Marshes
- support opportunities for the breeding and recruitment of native fish in the regulated Wambuul – Macquarie and Cudgegong rivers
- secure carryover for future use should conditions turn dry
- provide and improve habitat for waterbirds, frogs, rakali, platypus and other flow-dependent fauna
- provide ecologically valuable connections from the Barwon River to the Macquarie catchment.
Catchment conditions
Although winter 2024 was moderately wet, there were some constraints to delivery that impacted flow events in this season due to Burrendong Dam maintenance work in July.
Catchment rainfall helped set up the river system for effective environmental watering during spring 2024. Autumn 2025 was drier, and a notable rainfall event occurred in July.
The Mudgee area had an intense rainfall event in December 2024, which caused an unusually large fresh in the regulated Cudgegong River with localised flooding.
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, Healing Country program staff and environmental water managers organised workshops with 3 Aboriginal community groups to discuss updating the long- term water plan for the catchment. This led to the finalisation of the Wambuul – Macquarie-Castlereagh Long-Term Water Plan in collaboration with community members from Dubbo, Trangie and Mudgee.
An Aboriginal community member from Trangie is on the Wambuul – Macquarie-Cudgegong Environmental Water Advisory Group and we hope further Aboriginal community members will join the group.
Watering aims
Environmental water managers prepared an annual environmental watering plan in consultation with the Wambuul – Macquarie-Cudgegong Environmental Water Advisory Group. From this plan, the annual environmental water priorities in the Macquarie–Castlereagh catchment 2024–25 were developed in response to predicted moderate rainfall and water availability.
Aims for use of environmental water were to:
- maintain and improve the condition of the Macquarie Marshes wetland vegetation by inundating the inner 20,000 hectares of semi-permanent wetlands and river red gum woodlands for a suitable duration, including key nesting sites for waterbirds
- support native fish spawning and recruitment in the mid-Wambuul – Macquarie River by delivering a sequence of flow events
- support waterbird populations and other fauna in the Wambuul – Macquarie River by delivering water to wetland habitat as well as support successful breeding events for group-nesting waterbirds, should they occur
- support river and wetland processes while delivering water for other environmental objectives
- facilitate ecologically beneficial flow connectivity between the Wambuul – Macquarie and Barwon rivers if the opportunity arises or as part of water delivery for other objectives
- support native fish spawning and recruitment in the Cudgegong Regulated River, particularly instream specialists or species that rely on flowing water
- support river productivity and processes by providing flow variability
- secure water to carryover for use in future years.
Water delivery
This table and chart provide a summary of 216,508 megalitres of water for the environment delivered in the Macquarie catchment during the 2024–25 watering year.
The 205,666 megalitres of water for the environment delivered in the Wambuul – Macquarie River, was complemented by more than 77,000 megalitres of tributary flows and other water, as measured at Marebone Weir.
The 10,842 megalitres of water for the environment was delivered in the regulated Cudgegong River, with an additional 20,144 megalitres of other regulated flow at Rocky Waterhole, combining with further flows from various downstream tributary creeks.
Figures were accurate at the date of publishing but may be adjusted. Watering event numbers in the table and bar chart correlate with 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.
| Watering event number | Event name | Outcomes | Start date | Finish date |
|---|---|---|---|---|
| 1 | Macquarie Translucent EWA | Waterbirds, native fish, native vegetation, connectivity | 12 July 2024 | 18 June 2025 |
| 2 | Macquarie Spring Pulse | Waterbirds, native fish, native vegetation, connectivity | 26 August 2024 | 2 December 2024 |
| 3 | Cudgegong Spring Pulse and Base Flows | Native fish | 15 October 2024 | 1 March 2025 |
| 4 | Macquarie Autumn Fish Flow | Native fish | 16 March 2025 | 30 March 2025 |
Outcomes
In 2024–25, environmental water managers worked with the Wambuul – Macquarie-Cudgegong Environmental Water Advisory Group and the Commonwealth Environmental Water Holder to adaptively manage water to achieve annual objectives.
A moderately wet winter helped retain inundation of a core area of around 7,000 hectares in the Macquarie Marshes. Some translucent environmental water allowance flows were restricted by Burrendong Dam maintenance work in July 2024.
During a managed environmental water event in September and October 2024, inundation of the Macquarie Marshes extended to approximately 31,500 hectares. This receded through summer 2024–25. Rainfall and smaller flows over autumn and winter 2024 supported wetland inundation and helped retain a core area of around 6,000 hectares in March 2025. This inundation supported the growth and seeding of wetland groundcover vegetation and breeding of wetland animals such as waterbirds, frogs and native fish.
Flow targets set over summer 2024–25 in the mid-Wambuul – Macquarie River downstream of Warren Weir were generally successful. This included smoothing or controlling the rate of water level changes to a maximum of 30 centimetres per day and managing flows to maintain a minimum ‘floor’ or baseline of 300 megalitres per day at Warren Weir. We pursued a continuous flow at this minimum level to support native fish nesting. WaterNSW, working with the irrigation industry, achieved these outcomes with no environmental water required.
A fish dispersal pulse was managed for the mid-Wambuul – Macquarie River to support native fish. This was complemented by a translucent environmental water allowance pulse in July 2025.
In the lower Wambuul – Macquarie River, connectivity to the Barwon River occurred for around 200 days over the water year. Flows were consistently above 50 megalitres per day from July 2024 to January 2025 at Bells Bridge gauge. Flow readings from the gauge indicated when conditions were sufficient for the movement of large-bodied fish.
In the regulated Cudgegong River, a pre-breeding season productivity pulse flow was followed by a managed base flow event targeting at least 85 megalitres per day at Rocky Waterhole gauge. These actions aimed to support native fish spawning and recruitment.
Case study: a wisp of the Australian painted snipe in the Macquarie Marshes
Landholders made the significant discovery of a wisp, or group, of the Australian painted snipe in the Macquarie Marshes in the 2024–25 water year, one of our rarest resident waterbirds. Known for their elusive behaviour, these waterbirds forage at night and remain hidden in dense wetland vegetation during the day.
The sightings were confirmed by regional staff, who regularly observed between 10 and 15 painted snipe in a water couch meadow throughout spring 2024. Although breeding activity was suspected, no nests or chicks were found.
In a major step forward for conservation research, 5 of the birds were successfully captured using mist nets and fitted with radio transmitters. Scientists described the tracking as a rare and valuable opportunity to learn more about the species’ movements and habitat use.
The area supporting the snipe was inundated with managed environmental water during spring 2024 to help sustain the wetland habitat used by this endangered species for refuge and feeding.
