The Macquarie–Cudgegong Environmental Water Advisory Group met in November 2025 to review environmental water use, the outcomes of environment flows events, and plans for the remainder of the 2025–26 water year. The group also received an update on the growing global risk of H5N1 bird flu.

Catchment conditions

Burrendong Dam reached 67% capacity in September 2025 and, at the time of the meeting, had dropped back to 56%. Since July 2025, the dam has received around 320 gigalitres (GL) of inflows.
Windamere Dam remained steady during 2025, holding at around 90% capacity.

Environmental watering outcomes

Wambuul Macquarie River (Macquarie Marshes)

The Translucent Environmental Water Allowance flows and the spring pulse 2025 managed watering event occurred between July and October. The spring pulse was delayed by an administrative pause on watering affecting event timing and outcomes. Key results included:

  • a peak inundation area of 21,512 hectares (ha) in October 2025, confirmed by satellite and field checks
  • observations of a good diversity of waterbirds, including ibis, brolga, magpie geese and a rarely seen pied heron. Multiple pairs of the critically endangered Australian painted snipe were observed in the southern Macquarie Marshes. There were also several sightings of Australasian bitterns, which were heard calling at several sites.

Cudgegong regulated river

Water management in the Cudgegong River during spring and summer 2025–26 supported native fish populations through carefully planned flows. Water use began with a spring 2025 small fresh of 2.2 GL and continued with a sustained summer baseflow (aimed at maintaining approximately 85 megalitres (ML) per day at Rocky Waterhole) delivered through a combination of environmental water and other regulated sources. These elevated flows concluded on 1 March 2026.

Fish monitoring project

In mid-2025, 56 fish – including carp, golden perch, Murray cod and silver perch – were fitted with acoustic tags using an array of installed ‘listening stations’ along the Cudgegong River. The tags can be used to track individual fish for a period of 2 years. So far, tagged fish have been detected at 3 of 7 receiver sites. Monitoring is continuing to help us understand how fish respond to different river flows.

Upcoming environmental watering events

Two main environmental watering actions are planned for the rest of the 2025–26 water year:

  • Up to 10 GL of environmental water will be used over summer to stabilise river levels to support breeding and recruitment of the endangered freshwater catfish around Dubbo.
  • An additional 10 GL will be used to promote fish dispersal in late March 2026 to help fish move through the mid-Macquarie regulated system.

H5N1 bird flu information session

The group received a briefing on H5N1 bird flu, which poses a major global risk to wildlife and some risk to livestock and humans. Since 2020, it has caused millions of poultry deaths and affected more than 500 wildlife species worldwide.

Australia remains free of the virus, but early reporting is vital. The public is advised not to touch sick or dead birds and to report unusual bird deaths or multiple bird sickness to the Emergency Animal Disease Hotline on 1800 675 888.