Annual environmental water priorities in the Murrumbidgee catchment 2022–23

In 2022–23, water managers will continue to build on the success of previous years through the careful management of water for the environment.

Sunset over the Murrumbidgee with the trees lining the bank and the orange clouds reflected in the water

The Murrumbidgee catchment covers 81,527 square kilometres and includes 26 storage or diversion structures, 1,690 kilometres of the river, and the surrounding wetlands. The climate conditions range from alpine in the Snowy Mountains to semi-arid on the Riverina plains.

Wetlands throughout the Murrumbidgee support threatened species listed under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and NSW Biodiversity Conservation Act 2016.

The Traditional Owners of the Murrumbidgee are the Barapa Barapa, Mutthi Mutthi, Nari Nari, Ngarigo, Ngunnawal, Nyeri Nyeri, Wadi Wadi, Wolgalu, Wamba Wamba, Weki Weki and Wiradjuri Nations.

Water for rivers and wetlands

During 2021–22, the Department of Planning and Environment (the department) worked with the Commonwealth Environmental Water Holder to capitalise on wet conditions across the catchment to deliver water for the environment to sites including the Gayini Wetlands and instream Murrumbidgee River and Yanco Creek. Water was also used to benefit wetland habitats in the Murrumbidgee and Coleambally irrigation areas as well as the North Redbank wetlands, Forest Creek and Wanganella Swamp.

In 2022–23 managed watering events will initially focus on maintaining permanent water habitat for southern bell frogs, native fish, waterbirds and other aquatic species.

Water managers plan to supplement existing system flows to provide the maximum benefit to plants and animals. Watering events will aim to restore a more natural flow pattern to support a robust food web and other system functions. Water managers will ensure essential connections between the river and floodplain wetlands to aid in the movement of essential nutrients and native fish.

Weather and water forecast

The El Niño–Southern Oscillation (ENSO) outlook remains at La Nina, with a return to neutral ENSO during winter. The Bureau of Meteorology issued an outlook in April 2022 which forecasts above median rainfall for May to July 2022 for eastern mainland Australia, with the chance of exceeding median rainfall stated as greater than 80%.

Indicative starting allocations are 95% for high security and 35% for general security licences. Water management plans reflect these wetter conditions and are mindful of the favourable starting allocations and high carryover.

Water managers have prepared watering plans that consider a range of weather and water availability scenarios in case it rains more or less than expected. This is known as resource availability scenario planning. ‘Moderate to wet’ conditions are forecast for the Murrumbidgee 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

Dry

Main aim: Maintain

Maintain river functioning
Maintain key functions of high priority wetlands

 Macquarie River Trail, Dubbo

Moderate

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

Waterbirds

Water managers have planned flows up to 200 gigalitres (GL) to provide foraging and breeding habitat for waterbirds, turtles, frogs and other aquatic species in core areas of Yanga National Park, Gayini and the North Redbank wetlands. Flows will water key Australasian bittern habitats in the Murrumbidgee and Coleambally irrigation areas and Yanco Creek systems.

Native fish icon

Native fish

Water management plans allow for flows up to 100 GL to maintain instream and deep water off-stream habitats for native fish and to restore a more natural flow pattern to support native fish populations.

Native vegetation icon

Vegetation

Water managers will provide 10 GL of water for the environment via pumping to key mid-Murrumbidgee and Yanco/Forest Creek sites currently out of reach of river flows, e.g. Willbriggie Lagoon, Wanganella Swamp and Rhyola Swamps.

Connectivity and water flow icon

 Connectivity

Water managers have planned post airspace release and/or tributary event recession management flows up to 140 GL to inundate hundreds of mid-Murrumbidgee wetlands and the Lowbidgee lakes, while removing the effects of 3 weirs within the lower Murrumbidgee river channel and maximising fish passage (assuming reasonable starting allocations).

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

Map of the Murrumbidgee Water Resource Plan area 2022–23

The Department of Planning and Environment (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.

Source

Maximum volume available (gigalitres – GL)

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

Planned environmental water

 

Environmental Water Allowance (1)

100 GL
Linked to announced general security allocations

53.1 GL

Environmental Water Allowance (2)

Triggered by Burrinjuck Dam inflows and releases

26 GL

 

Environmental Water Allowance (3)

Linked to announced general security allocations

0 GL

Water licenced to New South Wales

 

General security

31.4 GL

7.85 GL
new allocation, approx. 9.4 carryover

Supplementary

6.7 GL

Dependent on surplus flows

Lowbidgee supplementary access licence (South Redbank/Yanga)

 148 GL

Dependent on surplus flows

Water licenced to the Commonwealth

High security

14.2 GL

Up to 13.5 GL

General security

286.5 GL

167.8 GL

Conveyance

50.3 GL

37.7 GL

Supplementary

22 GL

Dependent on surplus flows from unregulated tributaries

Lowbidgee supplementary

406.6 GL

Dependent on surplus flows

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 Planning and Environment enquiries on 1300 361 967.

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