Annual environmental water priorities in the Murray and Lower Darling Baaka catchments 2022–23

The Murray and Lower Darling Baaka catchments cover 98,300 square kilometres and include the world’s largest stand of river red gums and Australia’s longest river, the Murray. Ramsar-listed sites include the Millewa, Werai and Koondrook–Perricoota forests, Chowilla Floodplain and River Murray Channel.

Prior to the 2018–19 fish kills, the Lower Darling Baaka River supported one of the Basin’s most robust Murray cod populations and was an important flow corridor for golden perch.

The Murray and Lower Darling Baaka catchments’ wetlands and rivers support important Aboriginal cultural values, with more than 968 cultural sites formally recorded. Aboriginal people continue to contribute important knowledge to inform the management of water for the environment. The Traditional Owners of the Murray Lower Darling Baaka are the Wiradjuri, Dhudhuroa, Waywurru, Bangerang, Barapa Barapa, Wamba Wamba, Yorta Yorta, Barkindji, Maraura, Muthi Muthi, Nyeri Nyeri, Tati Tati, Wadi Wadi and Weki Weki (Central Murray). Barkindji, Maraura, Muthi Muthi, Nyeri Nyeri, Ngintait, Barkindji and Maraura (Lower Darling).

Water for rivers and wetlands

In 2022–23, managed water will target a range of outcomes, including:

• flow regimes that support the nationally threatened Australasian bittern and southern bell frog
• improved conditions for small-bodied native fish
• connectivity, refuge and dispersal flows for large-bodied native fish
• support for floodplain ecosystems, including the Central Murray Forest Ramsar site (Millewa, Werai and Koondrook-Perricoota).

The Lower Darling Baaka River and Great Darling Anabranch received a mix of natural high flows and environmental flows over winter, spring and summer 2021–22, providing good conditions for the recovery of native fish populations. Environmental water managers worked collaboratively with other agencies and the community to coordinate the delivery of releases. These interventions will contribute to improving native fish populations in the Murray–Darling Basin.

Weather and water forecast

The El Niño–Southern Oscillation (ENSO¹) outlook remains at La Nina, with a return to neutral ENSO during winter. Even as La Niña weakens, it will continue to influence global weather and climate. La Niña events increase the chances of above average rainfall across large parts of eastern Australia during Autumn.

Water managers have prepared watering plans that consider a range of weather and water availability scenarios. This is known as resource availability scenario planning. As of April 2022, ‘moderate’ or ‘wet to very wet’ conditions are forecast for the Murray and Lower Darling Baaka catchments 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

Key planned actions for 2022–23

Waterbirds

Water managers have planned:

• watering events for the Murray catchment national and regional parks to support sites that contain nesting Australasian bitterns and other native waterbirds. Australasian bitterns are an important story-telling species for Aboriginal people.
• deliveries of up to 1 gigalitre (GL) for Lake Agnes to promote waterbird breeding for threatened species such as blue-billed ducks
• deliveries up to 3 GL for Pollack Swamp which is a breeding site for egrets, herons, and little bitterns.

Native fish

Water managers have planned Murray River multi-site flows from Hume Dam to South Australia to support native fish and instream productivity.

Fish flows in the Edward-Wakool system will provide benefits for native fisheries, instream vegetation and food webs.

Water managers have planned a winter–spring flow for the Lower Darling Baaka River to support native fish recruitment. There is potential for a continuation of flow down the Great Darling Anabranch to the Murray River, water volumes permitting.

Vegetation

Water managers will deliver flows to private wetlands, providing critical habitat for southern bell frogs. Supporting the condition of remnant woodlands and other floodplain vegetation communities produces essential carbon and nutrients to support the aquatic food web and provides habitat and corridors for wildlife such as the nationally threatened superb parrot.

Connectivity

Flows will provide connectivity between Tuppal Creek and the Edward River, Cunninyeuk, Murrain Yarrein and Cockran-Jimaringle creeks and the Niemur, Wakool rivers and Yarrein Creek.

A cultural flow is planned in the Koondrook-Perricoota Forest. This will also benefit vegetation, woodland birds and waterbirds.