Annual environmental water priorities in the Gwydir catchment 2022–23

Water managers will respond to rainfall and natural flows to support water-dependent assets in the Gwydir catchment.

Looking down and along the tree-lined Gwydir River at Bingara, with mountains in the background

The Gwydir catchment covers 25,596 square kilometres. The eastern upland creeks mainly flow into the Gwydir River upstream of Copeton Dam. Downstream, on the western floodplain, the main Gwydir River splits into its main distributaries – the Mehi River (south), Carole Creek (north), Lower Gwydir and Gingham Channels (west/central).The Big Leather (Lower Gwydir) watercourse supports the State’s largest stand of marsh club rush. The Gingham Watercourse contains important colonial waterbird breeding habitats. The Gwydir wetlands are home to four wetland parcels listed under the Gwydir Ramsar landholder agreement. The Gwydir catchment supports important Aboriginal cultural values for the Kamilaroi/ Gomeroi people.

Water for rivers and wetlands

In 2022–23 water managers will use an adaptive approach to support fish and colonial waterbird populations and downstream connectivity by using water for the environment to maintain a natural flow regime. Contingencies are also in place to provide environmental flows to water-dependent assets when required.

The Gwydir catchment experienced improved water availability in the later part of 2020, with wet conditions continuing through 2021 and 2022. Major flooding occurred across the Gwydir River floodplain during March and April 2022.

During the 2021–22 water year, water managers used water for the environment to return flows into the downstream Barwon River via the Mehi River. Whittaker’s Lagoon was refilled. They also used water for the environment to support a significant colonial waterbird breeding event that occurred in the Gwydir Wetlands after natural flooding.

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 Central NSW.

Water managers have prepared watering plans that consider a range of weather and water availability scenarios. This is known as resource availability scenario planning. Moderate to wet conditions are forecast for the Gwydir catchment in 2022–23.

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


Heavy catchment rainfall, resulting in large river flows and floodplain flooding, may trigger colonial waterbird breeding events in the wetland systems. In response, water managers may provide 15–25 gigalitres (GL) of held water for the environment to support these events.

Native fish icon

Native fish

Water managers may use up to 25 GL to support native fish communities. Early season environmental flows may be triggered by inflows at Copeton Dam with a view to deliver supporting environmental flows later in the season.

Native vegetation icon


Water managers may use up to 40 GL across the catchment. Rainfall may trigger delivery of held environmental water into the Mehi River, Carole Creek and/or the Gwydir wetlands system. Water managers are likely to release further environmental flows into the Mallowa Watercourse this season to continue vegetation improvements.

Connectivity and water flow icon


Water managers may provide up to 14 GL of water for the environment in the Carole Creek, Mehi and Gwydir rivers this season to provide connectivity support to native fish communities during extended dry periods. In addition to in-valley connectivity, water managers may consider addressing connection to the Barwon River if warranted during the year.

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

Map of the Gwydir Water Resource Plan area 2022–23

The Department of Climate Change, Energy, the Environment and Water (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


Environmental water allowance

90 GL

90 GL

Water licenced to New South Wales


General security

25.5 GL

25.5 GL


 3 GL


High security

1.2 GL

1.2 GL

Water licenced to the Commonwealth

General security

134.2 GL

134.2 GL

High security

4.5 GL

4.5 GL


20.4 GL


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.