Ovens system

The Ovens River rises in the steep, forested mountains of the Great Dividing Range near Mount Hotham and flows about 150 km to join the Murray River in the backwaters of Lake Mulwala (Figure 5.3.1). The system has two small water storages: Lake Buffalo on the Buffalo River and Lake William Hovell on the King River. The regulated reaches of the Ovens system include the Buffalo and King rivers below these storages and the Ovens River from its confluence with the Buffalo River to the Murray River.

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 in drier years, and parts of the system can become flow-stressed during summer and autumn.

The Ovens River flows into Lake Mulwala on the Murray River; the lake is the largest weir pool on the Murray regulated system. The Ovens River flow contributes to the reliability and variability of the flow in the Murray River and supports 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. In recent years, private landowners have donated some of their annual water allocations to the VEWH to use in the King River. The Taungurung Land and Waters Council has also transferred some of their annual allocation to the VEWH to be delivered to the King River to heal Country.

The water transfers are 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 the flows of the Buffalo River and the lower Ovens River. It is also used to top up Mullinmur Wetland in Wangaratta.

Ovens pie chart

Proportion of water entitlements in the Ovens system held by private users, water corporations and environmental water holders on 30 June 2020

System map

Environmental watering objectives in the Ovens system

Maintain the size and distribution of native fish populations

Maintain the condition and extent of wetland vegetation communities

Maintain an adequate abundance and diversity of waterbugs to support river food webs and associated ecosystem processes

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 the re-introduction of native fish.

Traditional Owner cultural values and uses

The North East CMA consulted the Taungurung Land and Waters Council and the Yorta Yorta Nation Aboriginal Corporation in planning for potential 2023-24 environmental flows in the Ovens system.

The Taungurung Land and Waters Council water knowledge group Baan Ganalina (Guardians of Water) supports increasing Taungurung influence in water management, building internal capacity and advancing Taungurung water rights.

The Taungurung Country Plan’s water chapter Baan Dhumba-Dji-Ngan Mundak Gunga (We must speak to protect water) lists several water objectives. These include increasing and strengthening Taungurung voices, increasing water literacy and capacity, and returning water to disconnected wetlands. The future delivery of water for the environment by the Taungurung Land and Waters Council on Taungurung Country would contribute to achieving some of these objectives.

The Yorta Yorta Nation Aboriginal Corporation developed the Yorta Yorta Whole-Of-Country Plan 2021-2030. The plan outlines objectives for Yorta Yorta Country, including for the Ovens River, and it identifies the lower Ovens River as a very high priority for management actions. The plan’s objectives aim to support more culturally informed planning for water in the lower Ovens River in the future.

The Taungurung Land and Waters Council and the Yorta Yorta Nation Aboriginal Corporation are collaborating with the North East CMA on a 2022-24 project to update environmental flow recommendations for the Ovens system. The project aims to progress Taungurung and Yorta Yorta objectives. In 2023, Yorta Yorta Elders and people will conduct on-Country assessments along reach 5 of the Ovens River as part of this project.

The North East CMA has started conversations with the Bangerang Aboriginal Corporation, which has a representative on the Mullinmur Wetland Management Committee. In 2022, the corporation undertook cultural heritage assessments along the Ovens River at Wangaratta and at Mullinmur Wetland. These assessments identified many culturally significant features, including trees modified for cultural purposes and intact populations of plant species used in traditional practices (such as rope-making and medicine). The corporation has also been involved in management activities at Mullinmur Wetland, including cool weather cultural burning to suppress weed species and promote the growth of native vegetation.

Increasing the involvement of Traditional Owners in environmental water management and progressing opportunities towards self-determination in 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, including the Water Act 1989, the Victorian Aboriginal Affairs Framework, the 2016 Water for Victoria, the Water is Life: Traditional Owner Access to Water Roadmap 2022, 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 5.3.1 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.

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 its 39 ML entitlement in the King River system to support environmental objectives as part of its goal of healing and caring for Country. The council’s allocation has been released from Lake William Hovell five times as an environmental flow in partnership with the North East CMA, Goulburn-Murray Water and the VEWH to provide additional water to the King River and assist in healing Country.

Social, recreational and economic values and uses

In planning the potential environmental watering actions in Table 5.3.1, the 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/physical health and wellbeing)
community events and tourism (such as providing a setting for community gatherings, outdoor school learning, sporting events and citizen science projects)
socioeconomic benefits (such as businesses used by anglers and stock and domestic uses that rely on water quality, supported by deliveries of water for the environment when the natural flow is at its lowest from November to March).

Environmental flows are planned for Mullinmur Wetland in summer to re-establish submerged aquatic vegetation and support native fish at the site. The water is expected to sustain other benefits to the local community (such as recreation and amenity). The Mullinmur Wetland site is managed by the Catholic Education Department, supported by Wangaratta Landcare and Sustainability Incorporated. An education hub provides a space for environmental education for students from Galen Catholic College, young people attending the Borinya Wangaratta Community Partnership and other people from the local community, including a team of Waterwatch citizen scientists. These volunteers have been involved in monitoring changes in conditions for plant and fish species after deliveries of water for the environment.

Scope of environmental watering

The term ‘environmental watering’ refers to the active delivery of held environmental water to support particular environmental objectives by altering the flow in a river or the water level in a wetland. While other terms are sometimes used to describe the delivery of environmental water, ‘environmental watering’ is deliberately used here and in seasonal watering statements to ensure consistency in the legal instruments that authorise the use of water for the environment in Victoria.

Table 5.3.1 describes the potential environmental watering actions in 2023-24, their expected watering effect (that is, the intended physical or biological effects of the watering action) and the longer-term environmental objectives they support. Each environmental objective relies on one or more potential environmental watering actions and their associated physical or biological effects.

Table 5.3.1 Potential environmental watering actions, expected watering effects and associated environmental objectives for the Ovens system

Potential environmental watering action	Expected watering effects	Environmental objective
Buffalo River (targeting reach 1)
Summer/autumn low flow variability (greater than 70 ML/day for two days during February to April)	Increase connectivity between pools for fish movement Maintain waterbug habitat Maintain adequate oxygen levels in pools
Autumn low flow fresh (430 ML/day for three days 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 Maintain waterbug habitat Scour biofilm from the river bed
King River (targeting reaches 2 and 3)
Summer/autumn low flow variability (greater than 60 ML/day for two to four days during February to April)	Increase connectivity between pools for fish movement Maintain waterbug habitat Maintain adequate oxygen levels in pools
Mullinmur Wetland
Mullinmur Wetland (top-up during November to March)	Maintain the water level within the wetland to support the growth and recruitment of aquatic vegetation Maintain habitat and water quality for native fish

Page last updated: 01/07/22