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There are several environmental water holders in the Goulburn system. The Commonwealth Environmental Water Holder holds the largest volume and use of Commonwealth water for the environment 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 (see subsection 1.4.2). Water held by the VEWH in the Goulburn system is used to meet environmental objectives in the Goulburn River and the Goulburn wetlands.

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 regulated releases to meet irrigation and other consumptive demands during dry periods mean that flow downstream of these structures is typically low in winter and spring and high in summer and 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. If the opportunity arose to deliver water for the environment above current river thresholds at the right time to support improved environmental outcomes, water managers would consider it. Several tributaries including the Acheron and Yea rivers and the Broken River outfall downstream of Lake Eildon add some flow variation on top of the regulated flow regime in the Goulburn River. Large floods that cause the Goulburn River 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 River Murray. 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.

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
Cycle arrows
Provide sufficient rates of carbon and nutrient production and processing, to support native fish and waterbug communities
Plant icon
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 the riverine foodweb
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Minimise the risk of hypoxic blackwater after natural events

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 riparian 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 foodwebs, and dead trees that fall into the river provide a substrate 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 inundated 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 can trigger golden perch, silver perch and trout cod to spawn. However, these larvae do not appear to survive or remain in the Goulburn River and contribute to the local population.

Recent conditions

The Goulburn catchment has experienced drier-than-average conditions for most of the last six years. The main exception was 2016, when unregulated spring flows caused overbank flooding. This preceded another very dry summer and autumn in 2016–17, and since then the trend has been dry.

In the lower Goulburn River, most of the flow variation in 2018–19 was due to releases of water for the environment and IVTs, rather than natural (unregulated) flows. An exception was one small, unregulated flow event in August 2018, which reached about 1,500 ML per day at Murchison and 2,000 ML per day at McCoys Bridge. Water for the environment was used when necessary throughout the year to meet minimum low-flow requirements and to provide some high flows in winter and spring to support specific environmental outcomes.

Water for the environment was used to deliver a winter fresh in mid-June to mid-July 2018 to improve the bank vegetation, water quality and habitat for waterbugs and native fish. Improving the condition of the bank vegetation in winter/spring increases the resilience of plant communities and enables them to better withstand the effects of high river flows in the following summer and autumn. The VEWH is funding the Goulburn Broken CMA to undertake a monitoring project to investigate the impact of high summer and autumn flows in 2018–19. The outcomes of this project will inform future management decisions to improve environmental outcomes.

A combination of water for the environment and IVTs was used to deliver a spring fresh from late September to late October 2018, to allow the bank vegetation to establish and grow. Healthy bank vegetation helps to protect the riverbank from erosion, and vegetation at the water’s edge provides habitat for waterbugs and small fish.

In late August 2018, an IVT pulse up to 3,000 ML per day was delivered down the Goulburn River, which is the earliest an IVT has ever been delivered in the water year. IVT demand increased in mid-December 2018 and after Christmas, and releases from the Goulburn Weir near Murchison remained above 2,000 ML per day throughout January and February 2019. From late February and for the first week of March 2019, the river flow dropped to about 1,000 ML per day before again increasing above 2,000 ML per day as autumn irrigation demands increased. The total volume of IVT delivered down the Goulburn River in 2018–19 was the highest on record, and has tripled over the last four years. The duration of IVT has also increased in the last two years, with releases starting as early as August and ending as late as June.

A study commissioned in 2018 recommended that flow in the lower Goulburn River should not exceed 1,000 ML per day for more than a few weeks in spring and summer/autumn, to protect the bank vegetation. Despite collaboration between the Goulburn Broken CMA and Goulburn-Murray Water to try to limit environmental damage, it was not possible to achieve these flow recommendations and also supply downstream consumptive demand in 2018–19.

The vast majority of water for the environment delivered in the Goulburn River is reused at downstream sites along the River Murray. In 2018–19, Goulburn water was reused to meet native fish objectives in Gunbower Creek, inundate wetlands and significant floodplain habitats in Gunbower Forest and support ecological objectives in South Australia. 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

Potential environmental watering actions and objectives for the Goulburn River

Potential environmental watering1

Functional watering objective

Environmental objectives

Winter fresh (during July to August 2019, up to
15,000 ML/day with more than 14 days above 6,600 ML/day in reaches 4 and 5)

  • Improve macroinvertebrate habitat by improving water quality (reducing turbidity and mixing stratified water) and by increasing the wetted perimeter
  • Provide carbon (e.g. leaf litter) to the channel
  • Inundate bench habitats to encourage plant germination
  • Remove terrestrial vegetation and trigger the recruitment of native bank vegetation
Mountain iconsCycle iconPlant iconInsect icon

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

  • Provide slow, shallow habitat required for 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 low bank vegetation
  • Vary flow within a specified range to encourage planktonic production (for food), disrupt biofilms and maintain water quality
Fish iconCycle iconPlant iconInsect icon

Winter/spring variable low flows (between
800–2,000 ML/day in reach 4 during July to October)

  • Increase sediment and seed deposition on banks and benches
  • Support nutrient cycling
Mountain iconsCycle iconPlant icon

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

  • 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
Fish iconCycle iconPlant iconInsect icon

Spring fresh (> 6,000 ML/day for 14 days in August – September in reaches 4 and 5)

  • Inundate and water vegetation on the benches and lower banks, to support existing plants and facilitate recruitment
  • Increase soil moisture on the benches and banks, to sustain growth and increase vigour, flowering and seed development
  • Increase the extent of vegetation by distributing seed to riverbanks
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Flows should not exceed 1,000 ML/day for five to six weeks after a spring fresh (in late spring and summer) in reaches 4 and 5

  • Allow newly grown littoral emergent and amphibious plants to become established and persist
  • Provide bank stability
  • Provide habitat for small-bodied fish and macroinvertebrates
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Provide slower recession to unregulated flows, or add pulses following natural cues/ unregulated flows (in reaches 1 and 4)

  • Minimise the risk of bank erosion associated with rapid drawdown
  • Minimise the risk of hypoxic blackwater after natural events
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Winter fresh (in 2020, up to 15,000 ML/day with more than 14 days above 6,600 ML/day in reaches 4 and 5)

  • Improve macroinvertebrate habitat by improving water quality (reducing turbidity and mixing stratified water) and by increasing the wetted perimeter
  • Provide carbon (e.g. leaf litter) to the channel
  • Inundate bench habitats to encourage plant germination
  • Remove terrestrial vegetation and trigger the recruitment of native bank vegetation
Mountain iconscyclePlant iconInsect icon

Autumn fresh (one fresh of up to 6,000 ML/day for two days in March or April in reaches 4 and 5)1

  • 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 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 amphibious plants
  • Provide bank stability
  • Provide habitat for small-bodied fish and macroinvertebrates
Fish iconPlant iconInsect icon

1This autumn fresh will only be delivered if the average weekly flows in summer are less than 1,500 ML/day.

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
  • Individual landholders who are on the Goulburn Environmental Water Advisory Group
  • Commonwealth Environmental Water Office
  • Goulburn-Murray Water
  • Murray-Darling Basin Authority
  • Parks Victoria
  • Victorian Environmental Water Holder
  • A local ecotourism operator
  • Trellys Fishing and Hunting
  • Taungurung Land and Waters Council
  • Yorta Yorta Nation Aboriginal Corporation