Annual environmental water priorities in the Macquarie-Castlereagh catchment 2022–23

In 2022–23 water managers will aim to support the third year of a 3-year strategy for drought recovery in the mid and lower Macquarie Wambuul River.

An egret (a white bird) wades in the Macquarie Marsh with water reeds in the background

The Macquarie–Castlereagh catchment covers more than 75,000 square kilometres in the State’s central west. It extends from the Blue Mountains to the Barwon River plains, with major tributaries including the Cudgegong, Talbragar and Bell rivers.

The catchment is home to the iconic Macquarie Marshes – one of the largest semi-permanent wetland systems and colonial waterbird breeding sites in inland Australia.

The catchment supports important cultural values for Wiradjuri and Ngemba-Wayilwan people.

Water for rivers and wetlands

Increased rainfall and river flows since January 2020 have supported the recovery from the 2017–2019 drought.

Both planned and held accounts will be at 100% from 1 July 2022, with 334 gigalitres (GL) of the Department of Climate Change, Energy, the Environment and Water (the department) and Commonwealth Environmental Water Holder carryover available for the 2022–23 water year. Further rainfall could lead to the possibility of additional allocations early in the water year.

In 2022–23, water managers will target ongoing drought recovery outcomes for native fish, wetland vegetation, waterbirds and flow connection to the Barwon River.

Subject to regulated Water Sharing Plan amendment, a discretionary Environmental Water Allowance may be created in the regulated Cudgegong River in late 2022. This water has been managed to date as a rules-based translucent dam release. Water managers will plan the management of this allowance later in the year.

Weather and water forecast

The El Niño–Southern Oscillation (ENSO) outlook remains at La Nina, with a return to neutral ENSO during winter, meaning average or wetter conditions are likely. Further, the Bureau of Meteorology has forecast average temperatures in the Macquarie catchment.

Water managers have prepared watering plans that consider a range of weather and water availability scenarios. As at April 2022, conditions in the Macquarie– Castlereagh catchment are ‘wet’.

1. ENSO: The interaction between the sea surface and atmosphere over the Pacific Ocean which results in dryer or wetter conditions (El Nino or La Nina).

Resource availability scenario

 Dry river reaches in lower Mehi near Collarenebri gauge 2

Very dry

Main aim: Protect

Avoid critical loss
Maintain key refuges
Avoid catastrophic events

 Red Gum, "Hells Gate", now called "Black Rocks", Darling River


Main aim: Maintain

Maintain river functioning
Maintain key functions of high priority wetlands

 Macquarie River Trail, Dubbo


Main aim: Recover

Improve ecological health and resilience
Improve opportunities for plants and animals to breed, move and thrive

 Lower Murray

Wet to very wet

Main aim: Enhance

Restore key floodplain and wetland linkages
Enhance opportunities for plants and animals to breed, move and thrive

Key planned actions for 2022–23


Waterbird icon


An inundation event in the Macquarie Marshes during spring 2022 will provide habitat for waterbirds, including first-year birds from colonies in the Macquarie Marshes and wider Basin.

Native fish icon

Native fish

Water managers will use water for the environment to target native fish populations in the mid Macquarie Wambuul River.

The fish species targeted will depend upon conditions over spring. Flow generalists like Murray cod and eel-tailed catfish will be targeted if other river flows are relatively stable, while flow specialists including golden perch will be supported if conditions remain wet with variable flows.

Native vegetation icon


Water managers will deliver environmental flows during spring 2022 to support drought recovery for a third year. These flows will target the inundation of the inner 9,000 to 19,000 hectares of the Macquarie Marshes at a minimum.

Some riparian vegetation along the mid and lower Macquarie Wambuul River will be supported where flows are present. These flows will also recharge shallow groundwater systems and sustain vegetation that rely on this water source.

Connectivity and water flow icon


Connectivity to the Barwon has been consistent through 2021 and 2022. With a wetted Macquarie Marshes, it is expected spring flows in 2022 will provide extended flow connection along the lower Macquarie River to the Barwon River.

Figure 1 Map of proposed annual priority targets in the Macquarie–Castlereagh Water Resource Plan area 2022–23.

Map of the Macquarie-Castlereagh Water Resource Plan area 2022–23

The department is supporting the health and resilience of rivers and wetlands by delivering water for the environment where and when it is needed. We use the best available science, management expertise and experience to manage water across the landscape. This statement of annual priorities identifies the waterways and wetlands that are likely to receive water.

Our decision-making process considers:

  • expected availability of water in the coming year
  • conditions of the previous year
  • current health of the plants and animals in these ecosystems.

Community-based Environmental Water Advisory Groups (EWAGs) provide feedback and advice to the department on the management of water for the environment.

The NSW Government works with the Commonwealth Environmental Water Holder to manage water in the catchment.

First Nation objectives in the catchment are outlined in the Aboriginal Environmental Water Priorities.

Water for the environment is a share of the water in dams and rivers that is set aside to support the long-term health of local rivers, creeks and wetlands. Healthy rivers carry water to homes, farms, schools and businesses. Rivers and wetlands are important cultural and spiritual sites for Aboriginal people, as well as the broader community.


Maximum volume available (gigalitres – GL)

Volume expected 1 July under current conditions (gigalitres – GL)

Planned environmental water


Macquarie River Environmental Water Allowance

160 GL general security equivalent

160 GL

Cudgegong River Environmental Water Allowancee

11.4* GL general security equivalent

Approximately 11 GL ‘Residual Water’ made available at Water Sharing Plan commencement

Water licenced to New South Wales


General security

48.4 GL

48.4 GL


1.4 GL

1.4 GL


 2.9 GL

 2.9 GL

Water licenced to the Commonwealth

General security

126.2 GL

126.2 GL


8.3 GL

8.3 GL

* This is a combination of current allocations and future forecast allocations.

Notes: This is an indicative summary of expected volumes to be available. For further detail and information on available volumes please contact the region via Department of Climate Change, Energy, the Environment and Water enquiries on 1300 361 967.

1 gigalitre = 1000 megalitres; 2.5 megalitre = 1 Olympic swimming pool.