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Yarra River (Birrarung) Seasonal Watering Proposal 2022/23 Environmental Watering for the BirrArung & billabongs

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 2021/22

2021/22 so far has been a wet year, with streamflows naturally meeting many of the environmental targets for the Yarra River (Birrarung). Above average rainfall has meant some 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. Environmental entitlement has been used to help meet some flow recommendations throughout the year and deliver summer freshes.

Annulus Billabong has been watered in 2021, with other billabongs naturally inundated. Vegetation and frog responses to billabong watering have been monitored by the Wurundjeri Narrap rangers in a partnership with Melbourne University and Melbourne Water.

Annulus Billabong after watering, native vegetation returning

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 2022/23 under an “average” year scenario:

  • Summer/autumn low flows
  • Summer/autumn freshes
  • Autumn high flow
  • Spring high flow
  • Targeted billabong watering (Yering backswamp, Annulus and Bolin Bolin)
  • Plenty River winter/spring low flow
  • Plenty River winter/spring freshes
  • Cardinia Creek

It is estimated there will be approximately 39,000 ML of water in the Environmental Entitlement for the Yarra River.

Learn more and provide feedback on the 2022/23 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 1.30-2.30pm on Tuesday 1st March. 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.

EnvironmentalWater@melbournewater.com.au

Credits:

Doug Gimesy