Commonwealth water for the environment was first delivered in the River Murray Valley in 2008.
After the 2016–17 flooding event, the area experienced many years of little to no rain. During that time, environmental water was important in helping:
- sustain the health of plants, forests and woodlands
- maintain breeding and habitat of native fish and waterbirds
- reduce the risk of fish deaths by maintaining water quality
- maintain flows and waterway connectivity to prevent wetlands from drying
- flush salt from the river, and kept a continuous flow to the Coorong.
More recently, the conditions in the River Murray valley are most strongly influenced by 2 consecutive years of high flows. This includes one of the largest and most prolonged floods on record in 2022–23.
The latest achievements are below. To learn more about past water delivery, visit Past water use - River Murray Valley.
Flows and waterway connectivity
The River Murray is important for coordinating the use of water for the environment with other river valleys. This approach helps us achieve environmental outcomes along the whole length of the valley. This includes:
- supporting variable flows in the River Murray
- maintaining end-of-system flows through the Lower Lakes and into the Coorong
- enabling the movement of native fish between rivers, lakes and migration between salt and fresh water
- maintaining the ability to connect rivers to wetlands.
Vegetation, forests and woodlands
Water for the environment has helped maintain the condition of river red gum forests, especially since the 2016–17 flood. These benefits can be seen in:
- Barmah–Millewa Forest
- Gunbower Forest
Environmental flows have benefited woodlands at:
- Hattah Lakes
- Chowilla Floodplain
- Pike Floodplain
- Katarapko Floodplain.
Non-woody plants have also benefited from environmental flows. This includes:
- the Moira grass plains in Barmah-Forest
- aquatic plants in wetlands near weir pools
- increased abundance of plants fringing the Lower Lakes
- seagrass and Ruppia in the Coorong.
Native fish
High flow conditions observed in the Murray in recent years present both opportunities and risks to native fish.
There has been strong spawning and recruitment in native fish populations. This has occurred for the first time in several years.
On the other hand, the high flows enabled a boom in the number of invasive carp. Poor water quality events which occurred in the mid-Murray and Edward / Kolety-Wakool during spring 2022 also had a negative impact on native fish.
During the last 2 summers, golden perch have moved from the lower Darling / Baaka River into the River Murray. Environmental flows have helped this movement of native fish.
In the Edward / Kolety–Wakool rivers, the number of adult fish found in monitoring surveys were twice as high in 2022 than in previous years (2015 and 2019).
Water delivery has maintained populations of the endangered Murray hardyhead at several locations. Two new populations were established in recent years.
Waterbirds
The wet conditions in 2022–23 provided large areas of habitat for waterbirds. This resulted in large-scale breeding at numerous sites.
The flooding of Barmah-Millewa Forest during 2022–23 supported the nesting of thousands of waterbirds including:
- straw-necked and white ibis
- egrets
- little black and pied cormorants, and
- spoonbills.
A breeding group of Straw-necked and White ibis appeared at Boals Deadwoods in the Barmah Forest. This saw an estimated 2000 breeding pairs of ibis.
The endangered Australasian bittern bred in Millewa Forest for 2 successive seasons (2021–22 and 2022–23). This means the site continues to provide habitat for bitterns. Up to 25% of the bittern population are thought to rely on use of the Barmah–Millewa wetlands.
Populations of the vulnerable regent parrot have declined in recent years due to a reduction in river red gum health. Early observations indicate that the condition of nesting trees has improved in response to the 2022–23 floods.