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Water for the environment is supplied to the Latrobe River from Blue Rock Reservoir on the Tanjil River. Blue Rock Reservoir also supplies water for electricity generators in the Latrobe Valley and town water.

The Latrobe River from Rosedale to the Thomson River confluence (reach 5) is the priority reach for water for the environment because it contains endangered plant communities that have good potential for rehabilitation.

Storage manager
Environmental water holder

Environmental watering objectives in the Latrobe River

Fish icon
Maintain or increase native fish (migratory, resident and estuary) populations including eels
Frog icon
Increase frog populations and their range. Maintain refuge habitats
Landscape icon
Maintain or increase in-stream geomorphic diversity
Landscape icon
Maintain or increase in-stream geomorphic diversity
Platypus icon
Maintain or increase the abundance and increase the range of existing platypus and rakali (water rat) populations
Maintain the abundance of freshwater turtle populations
Plant icon
Improve the condition and increase extent and diversity of submerged, emergent and riparian vegetation
Insect icon
Increase the abundance of all macro- and micro-invertebrates
Water icon
Avoid adverse water-quality conditions (such as high salinity) in the lower Latrobe River and estuary

System map

Latrobe River and Wetland 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 values

The upper Latrobe River flows through state forest and is relatively intact and ecologically healthy. It contains continuous stands of river red gums and intact riparian vegetation, and it supports native animals including barred galaxias, river blackfish, Gippsland spiny crayfish and nankeen night herons.

The Latrobe River is regulated downstream of Lake Narracan and is highly degraded due to historic river management practices. Most large woody habitat has been removed from the river and many sections have been artificially straightened. These practices have caused significant erosion and widened the channel, which has in turn reduced the quality and quantity of habitat for aquatic plants and animals.

Endangered and vulnerable vegetation are found in all but the most modified sections of the Latrobe River. The banks along the lower reaches support stands of swamp scrub, characterised by swamp paperbark and tea tree. Mature river red gums grow adjacent to the lower Latrobe wetlands and provide nesting habitat for sea eagles and other birds of prey that hunt in the wetlands. The Latrobe River supports several native estuarine and freshwater fish including black bream, Australian bass, Australian grayling and short- and long-finned eel.

The Latrobe River and its tributaries provide an essential source of freshwater to the Gippsland Lakes system, of which the lower Latrobe wetlands are an important component.

Recent conditions

Climatic conditions in West Gippsland were warmer and drier than average during the 2018–19 water year. Sporadic heavy rainfall in late spring and early summer provided three freshes. An environmental flow was planned for the Latrobe River in November, to coincide with simultaneous environmental flows in the Thomson and Macalister systems. The coordinated releases aimed to deliver a large pulse through the system to support native fish migration and to water the lower Latrobe wetlands. While the environmental flows proceeded in the other systems, the water order was cancelled in the Latrobe system due to the sudden rainfall, meaning that the fresh was supplied mostly by natural flows from the upper Latrobe River and tributaries.

Summer and autumn rainfall was well below average. Low flows were provided in autumn, but a planned autumn fresh did not proceed due to minimal streamflows in the catchments. It was decided that conserving water for use in winter and spring 2019–20 would be more beneficial to the system.

Low flow recommendations were partially achieved from passing flows and unregulated flows during July to November 2018. Water for the environment was used to supply low flows in autumn for a short period, to allow instream bars to form and fish to move between habitats.

The environmental flow recommendations for the Latrobe River, Latrobe River estuary and lower Latrobe wetlands were updated in 2018–19. The updated recommendations take a more integrated approach to managing all the major waterways in the Latrobe system, and they have informed planning for 2019–20.

Scope of environmental watering

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

Potential environmental watering action

Functional watering objectives

Environmental objectives

Summer/autumn freshes (four to six freshes of 920–1,300 ML/day for four to 15 days during December to May)

Latrobe River objectives

  • Wet benches to maintain habitat and support the growth of emergent macrophyte vegetation
  • Support waterbug and zooplankton communities and maintain
    breeding substrate for blackfish
  • Flush sediment (sands and silts) from pools and mix water in pools, helping to provide habitat for frogs and spawning conditions for Australian grayling and blackfish
  • Provide longitudinal connectivity for platypus, rakali (water rats) and
    fish

Latrobe River estuary objectives (at upper magnitude; requires at least
930 ML/day in the Thomson River at Bundalaguah)

  • Upper estuary: fully flush with freshwater to support submerged vegetation, provide suitable conditions including dissolved oxygen
    levels for aquatic animals, transport silt, wet benches and deliver
    freshwater to connected wetlands
  • Mid-estuary: partially/fully flush the upper layer of the water column
    to improve water quality, support emergent macrophytes, provide
    freshwater habitat and associated food sources for freshwater fish
    and provide breeding opportunities for estuary fish
  • Lower estuary (at higher magnitude): partially flush the upper layer
    of the water column; a flow of this magnitude will also provide
    opportunities to fill to the lower Latrobe wetlands
Fish iconFrog iconMountain iconsPlatypus iconTurtle iconPlant iconInsect iconWater drop icon

Winter/spring freshes (four to
seven freshes of 2,200–2,710 ML/day for three to 20 days during June to November)

Latrobe River objectives

  • Wet banks to improve the condition of riparian vegetation
  • Provide a variety of wetted areas for emergent macrophytes
  • Wet the higher benches, to improve habitat and support the growth
    of riparian vegetation
  • Maintain channel capacity and bench habitat
  • Provide sufficient water depth over in-stream benches to support the growth and reproduction of waterbug communities, providing food for turtles

Latrobe River estuary objectives (at upper magnitude; requires at least 930 ML/day in the Thomson River at Bundalaguah)

  • Upper estuary: fully flush
  • Mid-estuary: partially/fully flush the upper layer of the water column to improve water quality, provide a variety of wetted areas for emergent and riparian vegetation and provide freshwater to support migration, habitat and associated food sources of freshwater fish and breeding opportunities for estuary fish
  • Lower estuary: partially flush the upper portion of the water column and create sufficient velocity to flush suspended silt
Mountain icons Turtle iconPlant iconInsect iconWater drop icon

Winter/spring low flows of
610–760 ML/day during June to November

Latrobe River objectives

  • Wet benches to maintain habitat and support the growth of emergent macrophyte vegetation
  • Support waterbug and zooplankton communities and maintain
    breeding substrate for blackfish
  • Flush sediment (sands and silts) from pools and mix the water column in pools, helping to provide habitat for frogs and spawning conditions for blackfish
  • Longitudinal connectivity for platypus, rakali (water rats) and fish

Latrobe River estuary objectives (at upper magnitude; requires at least 490 ML/day in the Thomson River at Bundalaguah)

  • Upper estuary: fully flush with freshwater to provide suitable
    conditions for waterbugs, to transport silt, to wet the benches and to deliver freshwater to connected wetlands
  • Mid-estuary: fully flush the upper layer of the water column to
    improve water quality and provide freshwater for migration, habitat and associated food sources for freshwater fish and breeding opportunities for estuary fish
  • Lower estuary: partially flush the upper layer of the water column; a flow of this magnitude will also provide opportunities to fill to the lower Latrobe wetlands
Fish iconFrog icon Mountain iconsPlatypus iconPlant iconInsect iconWater drop icon

Engagement

Table 2 shows the partners with which West Gippsland CMA engaged when preparing the Latrobe 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 longer term integrated catchment and waterway management objectives. For further details, refer to the West Gippsland Regional Catchment Strategy and West Gippsland Waterway Strategy.

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

Partner and stakeholder engagement
  • Greening Australia
  • Latrobe Valley Field Naturalists
  • Native Fish Australia
  • Gippsland Water
  • East Gippsland Catchment Management Authority
  • Parks Victoria
  • Individual landholders
  • Port of Sale Heritage River Cruises
  • Baw Baw Shire Council
  • Latrobe City Council
  • Wellington Shire Council
  • Southern Rural Water
  • Victorian Environmental Water Holder
  • Department of Environment, Land, Water and Planning
  • Field and Game Australia
  • VRFish
  • Gunaikurnai Land and Waters Aboriginal Corporation