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As its storages are quite small and spill regularly, the Ovens system maintains a large proportion of its natural flow regime, particularly in winter/spring. However, the storages and licensed water extractions throughout the system can restrict flow during low flow periods, and parts of the system can become quite flow-stressed during summer and autumn.

The Ovens River flows into Lake Mulwala on the Murray River, the largest weir pool on the Murray regulated system. Ovens River flows contribute to the reliability and variability of flows in the Murray River and support many downstream uses including irrigation, urban supply and watering of iconic floodplain sites (such as Barmah Forest).

Water for the environment is held in Lake Buffalo and Lake William Hovell and can be released when the storages are not spilling. Five reaches in the Ovens system can benefit from releases of water for the environment. While all are important, there is a relatively small volume (123 ML) of water available, and it is insufficient to meet most of the environmental flow objectives. The available water is used selectively to deliver the greatest possible environmental benefit. Water for the environment is most commonly used in the Ovens system to deliver critical flow events in reaches immediately below the two main storages, or it is used in conjunction with operational water releases to influence flow in the lower Ovens River. It is also used to fill and top up Mullinmur Wetland in Wangaratta.

Traditional Owners
Storage manager

System map

Environmental watering objectives in the Ovens system

Fish icon
Maintain the size and distribution of native fish populations
Landscape icon
Maintain the form of the riverbank and channel and ensure river bed surfaces are in suitable condition to support all stream life
Plant icon
Maintain the condition and extent of wetland vegetation communities
Insect icon
Maintain an adequate abundance and diversity of waterbugs, to support river food webs and associated ecosystem processes
Water icon
Maintain water quality for all river life

Environmental values

The diverse aquatic habitat and abundant food resources associated with the Ovens system support a wide range of native fish species including Murray cod, trout cod, golden perch and unspecked hardyhead. The Buffalo River provides valuable habitat for large-bodied fish species during part of their breeding cycle, while trout cod have a large range within the system and are found as far up the King River as Whitfield. A project to recover trout cod populations in the Ovens system has been successful, and efforts to reintroduce Macquarie perch are continuing.

Frogs (such as the giant banjo frog and growling grass frog) are abundant in the lower reaches and associated wetlands of the Ovens River and the King River above Cheshunt. The lower Ovens wetland complex contains over 1,800 wetlands, is listed as nationally significant and is home to a variety of waterbirds including egrets, herons, cormorants and bitterns. The streamside zones of river channels throughout the Ovens system support some of Victoria’s healthiest river red gum forests and woodlands, while the wetlands support a variety of aquatic and semi-aquatic vegetation communities.

Water for the environment was delivered to Mullinmur Wetland at Wangaratta for the first time in 2019-20. This site has been the focus of several environmental improvement projects in recent years. Specific management actions include carp removal, a revegetation program and a project that started in December 2019 to determine whether the wetland can support a sustainable brood stock population of native freshwater catfish. The Arthur Rylah Institute translocated 60 freshwater catfish into Mullinmur Wetland in December 2019, and ongoing monitoring throughout 2021-22 will assess the viability of the population.

Recent conditions

The Ovens catchment experienced slightly below-average rainfall across the 2020-21 season. Lake William Hovel received 80 percent of its long-term average inflows, and Lake Buffalo received 85 percent of its average inflows. Lake William Hovell began the season at full capacity, and rainfall through winter quickly filled Lake Buffalo, which reached full capacity by spring. Allocations against Ovens system environmental water shares remained at 100 percent during the season, and the Ovens River and reaches of the King and Buffalo rivers directly below their storages retained much of their natural flow variability throughout the year.

Local rainfall delivered natural, high-flow events in the Ovens system in July, August, October and February. The October event was the largest, with flow peaking at 11,300 ML per day in Wangaratta. Water for the environment was released in conjunction with operational bulk water transfers from Lake Buffalo, to deliver a small autumn fresh in late March to improve water quality and connect habitat for native fish and waterbugs in the Buffalo River (reach 1) and Ovens River (reaches 4 and 5).

Taungurung Land and Waters Council donated some of their annual water allocation to the VEWH to support environmental outcomes in the King River. This water and some water for the environment were released from Lake William Hovell in late March, to improve habitat quality and food resources for fish and waterbugs in reaches 2 and 3 of the King River.

Mullinmur Wetland was topped up with natural flows from the Ovens River in October 2020 and again in February 2021. These natural events negated the need for planned deliveries of water for the environment to the wetland in 2020-21. A native fish population assessment will determine if catfish stocked in Mullinmur Wetland moved into the Ovens River during the October or February high flow events. Surveys are also being conducted at Mullinmur Wetland to determine whether deliveries of water for the environment over the last two years have had the intended effect on native vegetation.

Traditional Owner cultural values and uses

North East CMA has consulted with the Taungurung Land and Waters Council and the Yorta Yorta Nation Aboriginal Corporation in planning for water for the environment for the Ovens system. The environmental and ecological objectives of the seasonal watering proposals were supported and align with the broad values of these Traditional Owner groups.

Taungurung Land and Waters Council are interested in identifying off-stream wetlands that require watering to improve the ecological and cultural values of their Country.

Yorta Yorta Nation Aboriginal Corporation has developed a new Whole of Country Plan, which will support more culturally informed planning for water in the lower Ovens River in future.

Increasing the involvement of Traditional Owners in environmental water planning and management, and ultimately providing opportunities to progress towards self-determination within and beyond the environmental watering program, is a core commitment of the VEWH and its agency partners. This is reinforced by a range of legislation and policy commitments (for example the Water Act 1989, the Victorian Aboriginal Affairs Framework, Water for Victoria (2016)) and, in some cases, agreements under the Traditional Owner Settlement Act 2010.

Where Traditional Owners are more deeply involved in the planning and/or delivery of environmental flows for a particular site, their contribution is acknowledged in Table 1 with an icon. The use of this icon is not intended to indicate that these activities are meeting all the needs of Traditional Owners but is incorporated in the spirit of valuing that contribution, and indicating progress towards this objective.

Billabong icons

Watering planned and/or delivered in partnership with Traditional Owners to support cultural values and uses

The Taungurung Land and Waters Council may consider using their water entitlement in the King River system to support environmental objectives as part of their goal of healing Country. The Taungurung Land and Waters Council’s allocation has been released from Lake William Hovell three times as an environmental flow in partnership with North East CMA, Goulburn- Murray Water and the VEWH, to provide additional water to the King River and assist in healing Country. The flow provided a small variation in the water level to inundate new habitat for in-stream biota (fish and macroinvertebrates), allowing them to move more freely and find new sources of food.

Social, recreational and economic values and uses

In planning the potential watering actions in Table 1, North East CMA considered how environmental flows could support values and uses including:

  • water-based recreation (such as boating and fishing)
  • riverside recreation and amenity (such as camping, visitation for mental health and wellbeing)
  • community events and tourism (such as providing a setting for community gatherings, school outdoor learning, sporting events, and citizen science projects)
  • socio-economic benefits (such as businesses used by anglers, stock and domestic use).

Environmental flows will be delivered to Mullinmur Wetland over summer, to support aquatic vegetation and support native catfish which were translocated to the wetland in 2019 from a drying lake in Barham, New South Wales. This site will continue to be used as a catfish broodstock location for future reintroductions into the region.

The water will also support other benefits for the local community, as the site is managed by the Catholic Education Department with support from Wangaratta Landcare and Sustainability Incorporated. It is used as a community environmental education site for Galen Catholic College students, young people attending the Borinya Wangaratta Community Partnership and other members of the local community, demonstrating the important ecological functions that wetlands provide and how water for the environment is used to support ecological values.

An education hub has recently been built at the site, providing a great space for school groups and community groups to develop and share knowledge in nature. Six photo points have also been placed around the wetland, to enable citizen-science opportunities. Anyone can take a photo from the specially made phone holders and upload them to Instagram, documenting the changes at the site.

A team of Waterwatch citizen scientist volunteers have provided water-quality recordings before and after environmental watering, helping waterway managers to understand the optimal conditions for native fish and plant species.

Scope of environmental watering

Table 1 Potential environmental watering actions, expected watering effects and associated environmental objectives for the Ovens system

Potential environmental
watering action

Expected watering effects

Environmental objective

Mullinmur Wetland (top- up during November to February)

  • Maintain the water level within the wetland to support the growth and recruitment of aquatic vegetation
  • Maintain habitat for freshwater catfish

Fish iconPlant icon

Autumn fresh (one fresh of greater than 430 ML/ day for three days in reaches 1 and 4, and greater than 130-260 ML/ day for three days in reach 5 during March to April)

  • Provide flow cues to stimulate the movement of native fish
  • Increase connectivity between pools for fish movement
  • Mix pools to improve the water quality
  • Provide small variations in river levels and velocity, to flush sediment from hard substrates and maintain waterbug habitat
  • Scour biofilm from the river bed

Fish iconInsect iconWater drop icon

Summer/autumn low-flow variability (greater than 80 ML/ day for one to two days during February to March in reaches 1, 2 and 3)

Billabong icon

  • Increase connectivity between pools for fish movement
  • Provide small variations in river levels to move sediment and maintain waterbug habitat
  • Maintain sufficient oxygen levels

Fish iconInsect iconWater drop icon


Table 2 shows the partners with which North East CMA engaged when preparing the Ovens system seasonal watering proposal.

Seasonal watering proposals are informed by longer-term regional catchment strategies, regional waterway strategies, environmental flow studies, water management plans and other studies. These incorporate a range of environmental, cultural, social and economic perspectives and longerterm integrated catchment and waterway management objectives. For further details, refer to the North East Regional Catchment Strategy and North East  Waterway Strategy.

Table 2 Partners engaged in developing the Ovens system seasonal watering proposal

Partner engagement
  • Wangaratta Landcare and Sustainability Incorporated
  • Commonwealth Environmental Water Office
  • Goulburn-Murray Water
  • City of Wangaratta
  • Victorian Fisheries Authority
  • Catholic Education Department – Sandhurst Diocese
  • Arthur Rylah Institute (Department of Environment, Land, Water and Planning)
  • Yorta Yorta Nation Aboriginal Corporation
  • Taungurung Land & Waters Council

Page last updated: 22/07/21