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There are several environmental water holders in the Goulburn system. The Commonwealth Environmental Water Holder (CEWH) holds the largest volume and use of Commonwealth environmental water is critical to achieving outcomes in the Goulburn River, as well as priority environmental sites further downstream. Water for the environment held on behalf of the Living Murray program may assist in meeting objectives in the Goulburn system en route to icon sites in the Murray system. Water held by the VEWH in the Goulburn system is primarily used to meet environmental objectives in the Goulburn River and the Goulburn wetlands, but can also be used to support ecological objectives at downstream sites along the Murray River and in SA.

The construction and operation of Lake Eildon and Goulburn Weir have significantly altered the natural flow regime of the Goulburn River. Water harvesting during wet periods, and releases to meet irrigation and other consumptive demands during dry periods, means that flow below these structures is typically low in winter/spring and high in summer/autumn. This effectively reverses the natural seasonal flow pattern. Land use changes and the construction of small dams and drainage schemes have further modified the Goulburn River’s flow regime. Levees and other structures prevent water inundating the floodplain and filling many of the natural wetlands and billabongs. Several tributaries including the Acheron and Yea rivers and the Broken River below Lake Eildon add some flow variation on top of the Goulburn River’s regulated flow regime. Large floods that cause the Goulburn River’s storages to fill and spill are also important for the overall flow regime and its associated environmental values.

The priority environmental flow reaches in the Goulburn River are downstream of Goulburn Weir (reaches 4 and 5), which are collectively referred to as the lower Goulburn River. The mid- Goulburn River extends from Lake Eildon to Goulburn Weir (reaches 1 to 3). From early spring to late autumn, large volumes of water are delivered from Lake Eildon to Goulburn Weir to supply the irrigation system. During that period, flow in the mid-Goulburn River is usually well above the recommended environmental flow targets. Deliveries of water for the environment have the most benefit in the mid-Goulburn River (especially in reach 1 immediately downstream of Lake Eildon) outside the irrigation season, when flow is much lower than natural.

Environmental flow targets can sometimes be met by the coordinated delivery of operational water being transferred from Lake Eildon to the Murray River. These transfers are known as inter-valley transfers (IVTs). These transfers occur during the irrigation season between spring and autumn, and they may meet environmental flow objectives without the need to release water for the environment. In recent years, operational transfers in the Goulburn River have significantly exceeded the environmental flow recommendations for summer and early autumn and have damaged bank vegetation and eroded the riverbanks. Interim operating rules have been put in place to help minimise this damage, and a review of the Goulburn to Murray trade rule is currently underway.

Traditional Owners
Storage manager
Environmental water holder

System map

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 Goulburn River

Fish icon
Protect and boost populations of native fish
Landscape icon
Maintain the form of the riverbank and channel including maintaining a high diversity of river bed surfaces to support all stream life
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Provide sufficient rates of carbon and nutrient production and processing to support native fish and waterbug communities
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Increase aquatic and flood-tolerant plants in the river channel and on the lower banks, to provide shelter and food for animals and to stabilise the riverbank
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Maintain abundant and diverse waterbug communities, to support riverine food webs
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Minimise the risk of hypoxic blackwater

Environmental values

The Goulburn River and its tributaries support a range of native fish species including golden perch, silver perch, Murray cod, trout cod, Macquarie perch and freshwater catfish. Aquatic vegetation, scour holes and woody debris within the channel provide high-quality habitat for adult and juvenile fish. River red gums are a dominant feature of the streamside zone along the length of the Goulburn River. These trees shade the river and provide habitat for many species including the squirrel glider. Leaves that fall from the river red gums provide carbon that supports riverine food webs, and dead trees that fall into the river provide a surface for biofilms and macroinvertebrates and habitat for fish. Birds (such as egrets, herons and cormorants) use trees along the river to roost and feed, while frogs benefit from shallowly- wetted vegetation at the edge of the river channel and in adjacent wetlands.

The Goulburn River system is an important conservation area for threatened species. Several wetlands in the Goulburn catchment are formally recognised for their conservation significance. Tributaries of the mid-Goulburn River between Lake Eildon and Goulburn Weir host some of the last remaining Macquarie perch populations in the Murray-Darling Basin, while freshwater catfish can be found in lagoons connected to reach 3 of the Goulburn River. Monitoring over recent years shows that environmental flows in the lower Goulburn River trigger golden perch and silver perch to spawn. However, further monitoring is required to determine how these spawning events contribute to populations locally and in the wider southern basin. Self-sustaining populations of Murray cod have been confirmed, and trout cod have been spawning and extending their range in the lower Goulburn River.

Traditional Owner cultural values and uses

Goulburn Broken CMA consulted with the Taungurung Land and Waters Council and Yorta Yorta Nation Aboriginal Corporation during the planning of environmental water deliveries in the Goulburn River. The environmental and ecological objectives of the proposals were supported and align with the broad values of these Traditional Owner groups.

Yorta Yorta Nation Aboriginal Corporation raised concerns about the cultural damage IVTs are having on the lower Goulburn River and the Barmah Choke in addition to the ecological damage being caused. Environmental flow deliveries and system planning in the Goulburn River aim to mitigate some of these impacts. Taungurung Land and Waters Council also shared these concerns, and strongly supports the implementation of a new operational rule for IVTs and the Victorian Government’s review of the trade rule to avoid further damage of the ecological and cultural values of the river.

Social, recreational and economic values and uses

In planning the potential watering actions in Table 1, Goulburn Broken CMA considered how environmental flows could support values and uses such as:

  • water-based recreation (such as boating and fishing)
  • riverside recreation and amenity (such as walking, camping and other outdoor activities)
  • socio-economic benefits (such as irrigation diverters and water supply for settlements on the Goulburn River).

The Goulburn River provides numerous recreational and economic benefits. Using water for the environment to provide fish passage and habitat and delivering freshes to encourage fish migration and spawning enhances native fish populations for recreational benefit. Following community feedback, the timing of a targeted environmental flow in November/December is planned to reduce impacts on river access, benefiting anglers and local businesses. This flow will be identified in Table 1 with an icon.

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Watering planned to support water angling activities

The delivery of the spring/summer fresh provides a cue for golden perch to spawn, and it is timed to minimise impacts on regional communities and businesses during the annual Murray cod opening weekend — the first weekend in December — while still ensuring the environmental objectives of the fresh can be achieved.

Recent conditions

Conditions in the Goulburn catchment in 2019–20 were very similar to those in 2018–19, with below-average rainfall in winter/spring. Temperatures throughout most of the year were above the long-term average, particularly in summer, leading to high evaporation rates from storages. Heavy rainfall in autumn helped replenish storages and resulted in a series of natural flows being passed at Goulburn Weir. Despite below-average inflows to Goulburn system storages in 2019–20, sufficient water was available for the environment through carryover and new allocation to meet high-priority flow requirements throughout the year.

Little natural flow occurred below Goulburn Weir in winter, and water for the environment was used to deliver a winter fresh in July 2019. This was followed by variable low flow that aimed to pass mid-Goulburn tributary inflows to the lower Goulburn River below Goulburn Weir. Conditions remained dry in spring, with a spring fresh delivered from September to October 2019 to support native fish and to trigger the germination of bank vegetation. IVTs started after the spring fresh, and no environmental water was delivered between mid-November 2019 and mid-March 2020. IVTs were delivered as a series of pulses (to reduce the effect on bank vegetation), but flows were consistently above the recommended environmental limit in summer/autumn. Although high IVT flows likely compromised some of the lower bank vegetation outcomes that were achieved by the spring fresh, wetting of the middle-to-upper bank during the spring fresh facilitated the growth and seed development of existing vegetation, provided carbon and nutrient cycling benefits and maintained habitat for waterbug communities. Higher rainfall in autumn delivered several natural flow events in the lower Goulburn River. Water for the environment was used to slow operational recessions after spills at Goulburn Weir, to minimise the risk of erosion and bank slumping.

Water for the environment delivered in the Goulburn River is reused at downstream sites along the Murray River, after a deduction for losses. In 2019–20, environmental flows that passed through the Goulburn River were subsequently used to support native fish objectives in Gunbower
Creek, wet wetlands in the Gunbower and Guttrum forests and the Hattah Lakes system, and support ecological objectives in SA. Water for the environment that is delivered from the Goulburn system makes a significant contribution to environmental objectives further downstream, which
helps to achieve environmental outcomes at the Murray-Darling Basin scale.

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for the Goulburn River

Potential environmental watering1

Functional watering objective

Environmental objectives

Year-round low flow (500-830 ML/day in reach 4 and 540-940 ML/day in reach 5)

  • Provide slow, shallow habitat required for the recruitment of larvae/juvenile fish and habitat for adult small-bodied fish
  • Provide deep-water habitat for large-bodied fish
  • Submerge snags to provide habitat for fish and waterbugs and a substrate for biofilms to grow
  • Maintain habitat for aquatic vegetation and water the root zone of lowbank vegetation
  • Vary flow within a specified range to encourage planktonic production (for food), disrupt biofilms and maintain water quality
cycleFish iconPlant iconInsect iconWater drop icon

Winter/spring fresh (one to two freshes of more than 6,600 ML for 14 days during July to October in reaches 4 and 5)

  • Improve macroinvertebrate habitat by improving water quality and by increasing the wetted perimeter
  • Provide carbon (e.g. leaf litter) to the channel
  • Wet bench habitats to encourage plant germination
  • Remove terrestrial vegetation and trigger the recruitment of native bank vegetation
cyclePlant iconInsect iconWater drop icon

Provide slower recessionto unregulated flows or releases from Goulburn Weir (3,000 ML/day and below in summer/autumn and from 6,000 ML/day in winter/spring) in reaches 4 and 5

  • Minimise the risk of bank erosion associated with rapid drying
  • Minimise the risk of hypoxic blackwater after natural events
Mountain iconsWater drop icon

Spring/autumn/winter low flow (400 ML/day during July to September and April to June in reach 1)

  • Wet and maintain riffles to provide habitat for biofilms and waterbugs
  • Scour fine sediment from the gravel bed and riffle substrate
  • Maintain the wetted perimeter of the channel and habitat for aquatic vegetation
  • Maintain existing beds of in-channel vegetation
  • Maintain habitat for small-bodied native fish
cycleFish iconPlant iconInsect icon

Winter fresh (up to 15,000  ML/day with more than 14days above 6,600 ML/day in June/July 2021, reaches 4 and 5)

  • Improve macroinvertebrate habitat by improving water quality and by increasing the wetted perimeter
  • Provide carbon (e.g. leaf litter) to the channel
  • Wet bench habitats to encourage plant germination
  • Remove terrestrial vegetation and trigger the recruitment of native bank vegetation
cycleMountain iconsPlant iconInsect iconWater drop icon

Flows should not exceed 1,000 ML/day for five to six weeks after a spring fresh (in late spring/summer) in reaches 4 and 5

  • Allow newly grown littoral emergent and semi-aquatic plants to become established and persist
  • Provide habitat for small-bodied fish and macroinvertebrates
Fish iconMountain iconsPlant iconInsect icon

One spring/summer fresh (greater than 6,600 ML for one day between November and December in reaches 4 and 5)

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  • Provide a cue for golden and silver perch to spawn
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Autumn fresh (one fresh up to 6,000 ML/day for two days between March and April in reaches 4 and 5)

  • Encourage the germination of new seed on the lower banks and benches
  • Improve water quality by reducing turbidity and mixing stratified water
  • Flush fine sediment from hard substrates to allow new biofilm growth and to improve food and habitat for macroinvertebrates
cyclePlant iconInsect iconWater drop icon

Flows should not exceed 1,000 ML/day (for more  than 20 consecutive days, with a minimum of seven days between pulses in summer/autumn in reaches 4 and 5)

  • Maintain for more than one season a littoral fringe of emergent or semiaquatic plants
  • Provide slow-flowing littoral habitat for small-bodied fish and macroinvertebrates
Fish iconMountain iconsPlant iconInsect icon

Engagement

Table 2 shows the partners and stakeholder organisations that Goulburn Broken CMA engaged when preparing the Goulburn River and Goulburn wetlands 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 Goulburn Broken Regional Catchment Strategy and Goulburn Broken Waterway Strategy.

Table 2 Partners and stakeholders engaged in developing the Goulburn system seasonal watering proposal

Partner and stakeholder engagement
  • Goulburn Valley Environment Group
  • Commonwealth Environmental Water Office
  • Goulburn-Murray Water
  • Murray-Darling Basin Authority (the Living Murray program)
  • Parks Victoria
  • Individual landholders who are on the Goulburn Environmental Water  dvisory Group
  • Local tourism operator
  • Trellys Fishing and Hunting
  • Scientific leads from the CEWO Monitoring, Evaluation and Research Program – Goulburn River
  • Yorta Yorta Nation Aboriginal Corporation
  • Taungurung Land & Waters Council

Page last updated: 24/07/20