Environmental water release for Yarra River

The upper reaches of the Yarra provide habitat for a range of native fish including river blackfish and spotted galaxias. The lower reaches contain Australian grayling, tupong and Macquarie perch. Billabongs are also an important feature of the river’s floodplain and support a range of vegetation, frog, and bird communities.

A number of reservoirs have been constructed in the Yarra system to capture and supply drinking water to Melbourne. These reservoirs change the pattern of river flows, as a majority of the flow is now captured.

In 2006, the Yarra River Environmental Entitlement was granted. This is a right to release water from the reservoirs to help keep the Yarra river system healthy. This release of water is known as an environmental flow.

Melbourne Water work’s with the Victorian Environmental Water Holder to manage this environmental water. We only make small or medium sized releases, and will not create flood events.

So how do we know what water the animals and plants need to stay healthy?

For example Australian grayling need rises in river flow to prompt them to migrate to the estuary around April to spawn. We think they then need a high flow in spring to encourage them to migrate back in to the Yarra to live out the remainder of their lives.

We monitor the flows in the river and if the flows do not occur naturally then a release from the reservoir may be made.

So how do we plan to use the water?

Melbourne Water plans and manages the use of environmental water working with the Victorian Environmental Water Holder, The recently developed Yarra River Environmental Water Management Plan lays out strategic direction for the use of the entitlement.

The Victorian Environmental Water Holder (VEWH) holds and manages a set volume of environmental water that is used to improve the health of rivers and wetlands across the State, including the Yarra River.

We use social media, community bulletins and our webpage to communicate our releases.

How do we plan a release?

The river still receives natural flows from unharvested creeks, constant low volume releases from reservoirs, and reservoir spills. These natural flows are often not enough to meet the needs of the river. The environmental entitlement can be used to top these up.

We monitor flows and make releases to mimic a natural event at the times of year when they are needed most.

The Yarra River is starting to return to good health and has improved since our first environmental release in 2011.

The monitoring that we have done following the delivery of environmental water is showing us that two of the threatened fish species in the river are benefiting from the environmental entitlement. During the long drought that ran from 1997 to 2009 there was real concern that populations of Australian grayling and Macquarie perch would disappear from the Yarra. Monitoring has shown the survival of young which will boost the populations of both of these fish in the river.

The Yarra River requires more than just water to be healthy. Other actions include fencing out cattle, revegetation for bank stabilisation and erosion control and installation of fishways to help fish to pass man made obstacles such as weirs.

There are many ways to enjoy the beauty of the Yarra. Walk along its paths, stop for a picnic, grab a canoe and go for paddle, or visit Dights Falls fishway to learn more about the how Melbourne Water’s work is helping boost the native fish population of the river.