What is Water for the Environment?
As Melbourne’s population has grown, many of its rivers and wetlands have been significantly modified to provide water for communities. In some rivers, up to half of the water that would have naturally flowed in them is diverted each year to provide water for homes, farms and industry.
To address this, Water for the Environment has been set aside in some reservoirs and dams that is then released into rivers and billabongs to improve their health and protect environmental values.
Melbourne Water works with the Victorian Environmental Water Holder (VEWH) to manage and release Environmental Entitlements from reservoirs to improve the health in four of Melbourne’s waterways: Werribee, Maribyrnong, Yarra and Bunyip-Tarago Rivers.
Why is Melbourne Water preparing a Seasonal Watering Proposal?
Melbourne Water develops a Seasonal Watering Proposal according to our statutory obligation under the Water Act 1989. This document assists VEWH to develop the Victorian Seasonal Watering Plan. This annual planning document outlines what environmental water releases will occur in the following year (July to June).
Sometimes the need for environmental water is higher than the water available to use. It’s therefore important to consider where water is most needed and how it can be used most efficiently to achieve the best environmental outcomes.
Water for the Environment delivered in 2023/24
Winter/spring of 2023/24 has experienced slightly below average rainfall conditions however unregulated streamflows naturally met many of the environmental targets for the Yarra River (Birrarung) due to unregulated tributary inflows. Most environmental flow events were met naturally; for example the winter/spring low flow requirement in all reaches and overbank flow events engaging the floodplain and billabongs. The environmental entitlement was used early in the year to provide water to Yering Backswamp before it was inundated by the Yarra River in October 2023. Conditions have become wetter over summer which will influence which environmental water deliveries are needed or not over the remainder of the year.
Yering Backswamp was watered in 2023 prior to being naturally inundated with most other billabongs during a series of flood events along the Yarra River (Birrarung). Vegetation and frog responses to billabong watering have been monitored by the Wurundjeri Narrap Rangers in a partnership with Melbourne University and Melbourne Water. Eel capture and tagging to help understand flow regime requirements was also undertaken with Arthur Rylah Insitute and the Wurundjeri Narrap Rangers. Wurundjeri Narrap Rangers and Melbourne Water had planned for a collaborative watering event to reconnect Bolin Bolin billabong with the Yarra River in late 2023 to allow eels to escape back to the main river channel, however the billabong connected naturally without the need to pump environmental water.
Key environmental values supported by Water for the Environment
- native fish (including threatened species such as Australian grayling, Macquarie perch and river blackfish)
- platypus
- frogs, particularly on the mid-Yarra floodplain
- waterbugs
- water quality, ensuring adequate dissolved oxygen concentrations
- native vegetation (in-stream, riparian and wetland)
- channel form, maintaining the physical environment
Opportunities for shared benefits are also incorporated into planning and watering decisions, if they do not compromise environmental outcomes.
Potential Watering Actions
We plan for all climatic scenarios, below are the proposed environmental watering actions for the Yarra River (Birrarung) in 2024/25 under an “average” year scenario:
- Summer/autumn low flows
- Summer/autumn freshes
- Autumn high flow
- Winter/spring low flows
- Winter/spring freshes
- Spring high flow
- Targeted billabong watering
It is estimated there will be approximately 37,000 ML of water in the Environmental Entitlement for the Yarra River.
Learn more and provide feedback on the 2024/25 Seasonal Watering Proposal
Engagement with Traditional Owners, local communities, management authorities and scientists is integral to understanding both the ecological values of waterways and how water for the environment can also provide a range of shared benefits including cultural, recreational and economic.
You are invited to attend an online information session 1:30-3:00pm on Wednesday 31st January. Register your attendance here.
Provide your feedback via a three question survey
If you would like a copy of the Melbourne Water Seasonal Watering proposal or would like to contribute to its development, please contact us at: EnvironmentalWater@melbournewater.com.au
We acknowledge the Traditional Owners of country throughout Victoria and Australia and pay our respects to them, their culture and their Elders past, present and future. Melbourne Water and its partners recognise the intersection between environmental flow objectives and Aboriginal cultural outcomes. We acknowledge the benefit of genuine, enduring partnerships with Aboriginal people in planning and managing water for the environment.
Photo credit for galaxias: Doug Gimesy