Murrumbidgee catchment

Magpie geese at Tori Lignum Swamp, North Redbank. Photo: Erin Lenon, CEWO

The Murrumbidgee River contains diverse and rich natural environments. Its waterways are a source of water supply for domestic use, extensive irrigated agriculture production, tourism, recreational activities, and the cultural values and practices of local Aboriginal Traditional Owners.

The Murrumbidgee region is home to the vast and nationally significant Lower Murrumbidgee River (Lowbidgee) Floodplain and the mid-Murrumbidgee River Wetlands. The Lowbidgee floodplain covers about 200,000 hectares and includes some of the largest lignum wetlands in New South Wales. It is an important bird breeding site, particularly for the royal spoonbill, great egret, straw-necked ibis, Australian white ibis and glossy ibis.

The Lower Murrumbidgee floodplain also contains the Gayini Nimmie-Caira project area, consisting of over 80,000 hectares of land that support a range of wetland-dependent species, including threatened species such as the Australian painted snipe, southern bell frog and the Australasian bittern. The Gayini Nimmie-Caira Enhanced Environmental Water Delivery project (the Gayini Nimmie-Caira Project) was established to protect, maintain and enhance the Nimmie-Caira environment, relax constraints to water delivery and help “bridge the gap” to Sustainable Diversion Limits in the Murrumbidgee. Following the 2013 purchase of Gayini Nimmie-Caira lands (with funding provided by the Commonwealth to NSW under a Heads of Agreement) in 2018 the NSW Government, through an open tender process, selected The Nature Conservancy in a partnership with Aboriginal and scientific groups to manage the Gayini Nimmie-Caira project area, which will provide:

ongoing environmental and indigenous cultural heritage protection;
indigenous engagement and participation; and
sustainable land use.

The Gayini Nimmie-Caira project was completed in 2019 on time and under budget. More information on the Gayini Nimmie-Caira project can be found at: The Nimmie-Caira Project.

The mid-Murrumbidgee River Wetlands are nationally significant, and support river red gum forests and blackbox woodlands that provide habitat to threatened species, again including the southern bell frog and the Australasian bittern.

The Murrumbidgee region is also home to the internationally significant Ginini Flats wetlands in the upper catchment, and the Ramsar listed Fivebough and Tuckerbil Swamps within the Murrumbidgee Irrigation Area.

Delivery of environmental water to date (as of November 2022)

Setting nets at Goorogool Lagoon, November 2019. Photo: Gaye Bourke, Charles Sturt University

Since 2009, Commonwealth environmental water has been delivered to sites across the Murrumbidgee catchment targeting both in-stream and wetland habitats to support their recovery or maintain their health.
Some of the significant contributions Commonwealth environmental deliveries have made to date, include:

maintaining critical refuge habitats for water dependent animals including waterbirds, native fish, birds, frogs and turtles. This includes protecting listed threatened animals from further decline or possible local extinctions;
re-establishing the threatened southern bell frog populations in the mid-Murrumbidgee (locally extinct for 40 years) and at Yanga National Park (not detected between 2013 and 2017);
re-establishing important native wetland plant communities in the mid-Murrumbidgee that had been lost from wetlands;
supporting successful breeding outcomes and maintaining important habitat for over 30 waterbird species;
restoring the natural watering frequency of wetland sites in the mid-Murrumbidgee, Lowbidgee floodplain and Junction Wetlands to support their recovery; and maintain and/or improve their ecological condition;
maintaining the ecological character of internationally listed Ramsar wetlands, Fivebough and Tuckerbil, and supporting the waterbirds that depend on them;
supporting the spawning and growth of eight native fish species into local populations;
reducing the impact on native fish and other water dependent animals from very poor water quality (lethally low dissolved oxygen concentrations) in response to natural flooding in 2016 and 2021;
avoiding further fish deaths in Lowbidgee weir pools caused by very poor water quality that developed in response to low flows in the river and high temperatures associated with drought in 2019.
Triggering and supporting numerous waterbird breeding events across the valley including several consecutive large-scale breeding events of more than 18,000 pairs of predominantly straw-necked in the Lowbidgee. Other species that also successfully bred included egrets, spoonbills, herons, cormorants, darters, swans, threatened blue-billed and freckled ducks, brolgas and Australasian and little bitterns.
Successfully recovering the threatened southern bell frog population in the Lowbidgee to pre-Millennium drought numbers after the population came close to becoming locally extinct during the drought.
Supporting the spawning and recruitment of golden perch on the Yanga National Park floodplain and providing flows to assist fish passage between the Murrumbidgee and Murray.

The Murrumbidgee Valley experienced dry conditions from early 2017 up until a transition to wetter conditions from early 2020. With the continuance of wet conditions and high water resource availability into 2022-23, the primary focus for use of Commonwealth water for the environment is to maintain, and where possible improve the health and resilience of aquatic ecosystems. This will be achieved by targeting in-channel fish movement; facilitating connection between the floodplain and river channel for fish and nutrient dispersal and larger scale wetland and floodplain inundation to improve habitat condition. Due to prolonged periods of high unregulated flows, no Commonwealth water for the environment has been used in the Murrumbidgee catchment as of early November 2022.

What has environmental water achieved in the Murrumbidgee?

Scientific monitoring shows environmental water delivered to the Murrumbidgee is providing food, habitat and breeding opportunities for many of the region’s native fish, frogs, waterbirds, plants and other wildlife.

A summary of preliminary results for 2021-22 are below with full monitoring reports available each year.

2021-22

Tuckerbil Swamp. Photo: Michele Groat, CEWO

Repeated high unregulated flows met many of the environmental demands in the Murrumbidgee River catchment in 2021-22. Despite this, it was the biggest water for the environment use year in the Murrumbidgee with over 588 GL delivered. Commonwealth water for the environment was delivered to complement and build on unregulated flows with objectives to enhance habitats and threatened species populations, build ecological resilience and capacity for recovery.

Delivery of Commonwealth and NSW water for the environment successfully:

supported breeding of an estimated 20,000 straw-necked ibis nesting pairs and smaller numbers of many other species, at Bala (Eulimbah Swamp) in Gayini Nimmie-Caira for the second consecutive year.
supported approximately 11,200 pelican nests at Kieeta Lake in Gayini Nimmie-Caira
supported at least 29 active colonial waterbird breeding sites across the Mid-bidgee, Yanco Creek system, Lowbidgee wetlands and including the Junction wetlands; with breeding of numerous species including threatened Australasian and Little bitterns, egrets, spoonbills, herons, cormorants, darters, little grebes, Pacific black and musk ducks, and Eurasian coots
an estimated 45,000 – 50,000 waterbird nests were active in the Murrumbidgee Selected Area in 2021–22. This is comparable to the number of waterbird nests recorded in the last major natural flood event in 2016–17
supported 6 species of frogs (Barking and Spotted marsh frogs, Peron’s tree frog, Plains froglet, Inland banjo frog and the threatened Southern bell frog)
the detection of the threatened Southern bell frog at Western Lakes for the first time as well as supporting distribution of this species in the Coleambally Irrigation Area in all but one of the wetlands that received environmental water.
supported movement of native fish between the Murrumbidgee and Murray rivers, and between the Murrumbidgee River and floodplain creeks and lakes in Yanga National Park by expanding on unregulated flows in the mid-Murrumbidgee and the lower Murrumbidgee River (these flows also provided opportunity for critical exchange of carbon and nutrients)
contributed flows to mitigate low dissolved oxygen in the lower Murrumbidgee River and Yanco Creek system to protect aquatic animals, including native fish
supported populations of a range of native fish, including Carp gudgeon, Australian smelt, Flathead gudgeon, Bony bream, Murray–Darling rainbow fish, unspecked hardyhead, Murray cod, Golden perch and Freshwater catfish
maintained suitable habitat for waterbirds, native fish and frogs in the Western Lakes, Wanganella Swamp and Rhyola Wetland
provided habitat and recruitment opportunities for water dependent animals, including waterbirds in important MIA wetland (Nericon Swamp)
supported all 3 Murrumbidgee turtle species (Broad shelled, Eastern long-necked and Macquarie River turtles) found in the catchment.
extended the duration and managed the recession of three unregulated flow events to maximise mid-Murrumbidgee wetlands and river connectivity. These flows also:
- supported movement of native fish between the Murrumbidgee and Murray rivers, and between the Murrumbidgee River and floodplain creeks and lakes in Yanga National Park
- through Prerequisite Policy Measures, met objectives in the River Murray, and the Coorong and Lower Lakes for native fish and salinity mitigation.

Details of previous Commonwealth environmental use in the Murrumbidgee River Valley are available at: History - Murrumbidgee.

Our partners

Sunshower Lagoon after receiving environmental water in 2019-20. Photo: Vince Bucello

Commonwealth environmental water use is planned, delivered and managed in partnership with a number of individuals and organisations in the Murrumbidgee River region including: