When the conditions are right in spring, the wetlands of the Murray-Darling Basin come alive with the sights and sounds of breeding waterbirds.
This seasonal event is not just a natural wonder. It is a vital ecological process supported by water for the environment.
What is water for the environment?
Water for the environment is water used to protect and restore our rivers, wetlands, and floodplains. When rivers are connected to wetlands and floodplains, the plants, animals and people living along the rivers thrive because the rivers are healthy.
Since 2009, the Commonwealth Environmental Water Holder (CEWH) has worked with partners to deliver more than 18,000 gigalitres of Commonwealth water for the environment. These flows and freshes are released strategically and play a crucial role in copying natural flows - especially during spring when many species begin to breed.
Spring: a critical breeding season
Spring marks the peak breeding period for a wide range of waterbird species, including:
- Australasian darter
- Australian pelicans
- cormorants - great, little black, and little pied cormorant
- egrets - eastern great and intermediate egret
- herons - nankeen night-heron, white-faced, and white-necked heron
- ibis - glossy, straw-necked, and white ibis
- spoonbills - royal and yellow-billed spoonbills
- threatened species - Australasian bittern (nationally endangered), blue-billed duck (vulnerable - NSW), and freckled duck (vulnerable - NSW).
These birds rely on flooded wetlands to build nests, find food, and raise their young. Without stable water levels, breeding attempts can fail.
How does environmental water help?
We use environmental water to help:
- extend wetland inundation to allow chicks time to fledge.
- maintain water levels around nests to prevent abandonment and predation.
- support food availability for adult birds and chicks.
- trigger small-scale breeding events.
During spring 2020, more than 200,000 megalitres of water for the environment was delivered across approximately 30,000 hectares in the central Basin. This supported a mass breeding event of tens of thousands of waterbirds.
In the 2022-23 season alone, more than 183,000 active nests were identified in the Murrumbidgee area. This is one of the largest breeding events since monitoring began.
Monitoring and collaboration
As part of our science program - Flow-Monitoring, Evaluation and Research (Flow-MER) - we monitor, research, and evaluate how environmental water supports waterbirds. This helps us to protect important wetlands and the birds that rely on them.
Monitoring includes aerial surveys, drone imagery, and ground counts, as well as satellite tracking of birds to understand their movements and habitat use.
These efforts are supported by a network of partners including:
- First Nations peoples
- University researchers
- Water management authorities.
Why it matters
The use of water for the environment in spring is not only for waterbirds. Environmental water helps to revive entire ecosystems, from aquatic plants to fish and frogs. It builds resilience in the face of climate variability and supports biodiversity across the Basin.
To learn more, visit Waterbird Habitat & Breeding Insights | The Flow-MER Program.
