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The Yarra River flows west from the Yarra Ranges upstream of Warburton and through the Yarra Valley. It then opens out into a wider plain as it meanders through the suburbs and city of Melbourne before entering Port Phillip Bay. The Upper Yarra Reservoir, O'Shannassy Reservoir and Maroondah Reservoir harvest water from headwater tributaries and a pump station at Yering is used to divert water from the Yarra River to Sugarloaf Reservoir.

Flows through the Yarra system have become highly regulated due to the construction of major water storages that capture natural run-off and allow the controlled removal of water for consumptive use. Over time, the lower Yarra River has been straightened, widened and cleared of natural debris as Melbourne has grown around its banks. The earliest recorded alterations to its course date back to 1879. Environmental watering aims to reinstate flows that support ecological processes and environmental outcomes throughout the length of the system.

Environmental water can be released from the Upper Yarra, Maroondah and O'Shannassy reservoirs. Priority reaches for environmental watering are reaches 2 and 5 and delivery of water to these reaches is expected to also achieve flow targets in neighbouring reaches. Figure 3.2.1 shows the environmental flow reaches in the Yarra system. In the upper reaches, the system is influenced by tributaries (such as Woori Yallock Creek, Watts River and Little Yarra River). In the lower reaches, urbanised tributaries (such as Olinda Creek, Mullum Mullum Creek, Diamond Creek, Plenty River and Merri Creek) provide additional water to the Yarra River.

Waterway manager
Storage manager
Environmental water holder

System map

Yarra System
Grey river reaches have been included for context. The numbered reaches indicate where relevant environmental flow studies have been undertaken. Coloured reaches can receive environmental water.

Environmental watering objectives in the Yarra River

Plant icon
Increase, strengthen and maintain plant life on the riverbank and in the channel, as well as on the upper Yarra floodplain and in the river’s billabongs
Fish icon
Protect and increase populations of native fish including threatened species (such as the Australian grayling and Macquarie perch)
Landscape icon
Maintain the form of the riverbank and bed

Scour silt build-up and clean cobbles in the river to ensure fish, platypus and other water animals have access to healthy habitat pools and places to feed, spawn and shelter
Insect icon
Protect and increase communities of waterbugs, which provide energy, break down dead organic matter and support the river’s food chain
Water icon
Improve water quality in river pools, ensuring there is plenty of dissolved oxygen in the water to support water animals and bugs

Environmental values

The upper Yarra River (reaches 1–3) provides habitat for a range of native fish species including the river blackfish, spotted galaxias and common galaxias, and contains good-quality riparian and aquatic vegetation. The lower river (reaches 4–6) flows through forested gorges, cleared floodplains and some highly urbanised areas, and it supports several populations of native fish including Australian grayling, Macquarie perch and tupong. Macquarie perch were introduced to the Yarra River last century, and the population is now considered one of the largest and most important in Victoria.

Billabongs are an important feature of the Yarra River floodplain between Millgrove and Yering Gorge as well as of the reach around Banyule Flats near Heidelberg. The billabongs support distinct vegetation communities and provide foraging and breeding habitat for waterbirds and frogs. Except in very high flows, most billabongs are disconnected from the Yarra River.

Social, cultural and economic values

The upper reaches of the Yarra River provide 70 percent of Melbourne's drinking water. They also provide social and recreational opportunities for the more-than four million people who live in the greater Melbourne area. Swimming and kayaking are popular in some sections, and many sections have aesthetic appeal for walkers and cyclists. The Yarra supports more than 2,450 ha of urban parklands and public open space along its corridor, which is valued by the public for its tree-dominated landscape and views of and access to the river. Private tourism and recreation industries also make use of the river aspect; for example, there are more than 10 golf courses along the river's length.

The waterways of the Yarra system (including the Yarra River) hold significance for Aboriginal Victorians and their Nations in the region. For the Wurundjeri people, who have a spiritual connection to the Yarra's lands and waterways, the river is a life source that has been etched into the landscape by the ancestral creator spirit Bunjil (meaning eagle). They name the river Birrarung (meaning shadows of the mists). Melbourne Water and the VEWH have started working with the Wurundjeri Tribe Land and Compensation Cultural Heritage Council to understand how environmental water management in the Yarra River can better support Aboriginal aspirations, particularly around caring for Country and protecting important story places and cultural resources.

Conditions mid-2017

The Yarra River catchment experienced below-average rainfall and dry conditions from 2014 to the start of the 2016–17 water year. Above-average rainfall between August and October 2016 caused a shift to average and then wet conditions. Environmental water planning mirrored these changes, with a shift from dry scenario planning at the start of the 2016–17 water year to average-wet scenario planning by spring.

Low flows during 2016–17 were consistently achieved with unregulated flows and there was no need to provide any additional environmental water. The average-to-wet conditions also allowed environmental water to be delivered to Yering backswamp and Banyule billabong. Spadonis billabong was filled naturally after works were completed to lower the adjacent riverbank.

Environmental water was mainly used in 2016–17 to deliver summer and autumn freshes to improve water quality and improve habitat for fish and waterbugs. An autumn highflow event was also delivered in May to trigger spawning of Australian grayling.

The wet conditions experienced through much of 2016–17 and reduced demand for environmental water in 2016–17 means that more water is likely to be available to meet high-priority watering actions in 2017–18.

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for the Yarra system



Year-round low flows2 (varying rates from 10–350 ML/day)
  • Maintain access to riffle and pool habitat for waterbugs and fish
  • Allow the riverbank vegetation to dry
  • Limit the growth of fringing/riparian/terrestrial vegetation into the
    stream channel
  • Maintain and/or rehabilitate in-stream vegetation

Summer/autumn freshes (1–4 freshes of varying rates between 60–750 ML/day for 2–4 days each
in December–May)

  • Maintain habitat by scouring sediments and cleaning cobbles in
    faster-flowing areas
  • Provide access to suitable habitat and migration opportunities for
    native fish
  • Maintain flood-tolerant vegetation on the low banks
  • Improve water quality in pools

Winter/spring freshes (2 or more freshes of varying rates between 100–2,500 ML/day for at least 2–7 days in June–October)

  • Maintain habitat by scouring sediments and cleaning cobbles in
    faster-flowing areas
  • Maintain flood-tolerant vegetation on the low banks
  • Provide migration opportunities for native fish
  • Improve water quality in pools

Targeted billabong watering

  • Support the native vegetation and improve habitat availability for
    wetland plants and animals

Spring high flow (1 high flow of 700–2,500 ML/day for 14 days in October–November)3

  • Promote spawning and migration of native fish species

1 The magnitude and duration of potential environmental watering depends on the reach being targeted, with the lower range generally occurring in the upper reaches (for example, reach 1) and higher range in the lower reaches (for example, reach 6).

2 Low flows are generally provided by passing flows under the environmental entitlement but during dry conditions it may be necessary to supplement low flows using environmental water.

3 A spring high flow will only be achieved with significant unregulated flow due to release constraints in the upper reaches of the system. However, ceasing harvesting at Yering during a natural high flow may assist in the desired flow being achieved.

Risk management

In preparing its seasonal watering proposal, Melbourne Water considered and assessed the risks of environmental watering and identified mitigation strategies. Program partners continually reassess risks and mitigation actions throughout the water year

Engagement

Waterway managers meet communities on environmental watering regionally, although other program partners also play a role.

In each region of Victoria, community engagement on environmental watering happens when environmental watering objectives and priorities are scoped (long term and annually), when delivering environmental water, and when reporting on environmental watering results.

Communities in the Melbourne region are involved in decisions about the Tarago, Yarra and Werribee river systems through each system's Environmental Water Advisory Group.

Who is engaged and how

Recreational users

Through formal advisory groups coordinated by Melbourne Water, representatives of recreational user groups are engaged. Advisory group members receive notifications about planned environmental water deliveries via the community bulletin.

For recreational users, safety related to higher water levels are a key concern.

On occasion, Melbourne Water informs recreational users directly about environmental watering (such as the Werribee fishing club or Canoes Victoria).

Environment groups

Representatives of environment groups are engaged through formal advisory groups coordinated by Melbourne Water. Advisory group members receive notifications about planned environmental water deliveries via the community bulletin.

Melbourne Water has informal relationships with various environment groups (such as Landcare, Birdlife Australia, Yarra Riverkeepers, Environment Victoria and Waterwatch) and meet with these groups on an as-needs basis.

Some groups, such as Waterwatch, share monitoring information with Melbourne Water.

Landholders/farmers

Through the Yarra Diversions newsletter, diversions licence holders receive information and updates on environmental watering.

Landholders and farmers are engaged through formal advisory groups coordinated by Melbourne Water. Advisory group members receive notifications about planned environmental water deliveries via the community bulletin.

Traditional Owners

Melbourne Water is doing a collaborative project with the Wurundjeri Tribe Land and Compensation Heritage Council and the Victorian Environmental Water Holder to document the Wurundjeri cultural values in the Yarra river system. The aim of this project is to increase understanding of values that can be supported with environmental water to achieve shared benefits for Aboriginal people from environmental watering (Aboriginal environmental outcomes).

Councils

Through formal advisory groups coordinated by Melbourne Water, Council representatives (from various local councils across region) are engaged. Advisory group members receive notifications about planned environmental water deliveries via the community bulletin.

Melbourne Water publishes an annual two-pager for each Council about activities undertaken in their catchment, including delivery of environmental flows.

General public

Melbourne Water communicates and engages with the general public through their website, media releases and Facebook and Twitter. Melbourne Water community bulletins are posted on their webpage, Facebook and Twitter, and issued to media contacts.