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River regulation and water extraction from the Latrobe, Thomson and Macalister rivers has reduced the frequency of small- and medium-sized floods that naturally wet the lower Latrobe wetlands. Construction of levees and drains and filling of natural depressions have also altered water movement into and through the wetlands. The drainage and flooding regime in all three wetlands is now managed to some extent with regulators connected to the Latrobe River.

Traditional Owners
Storage manager
Environmental water holder

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 watering objectives in the lower Latrobe wetlands

Maintain the abundance of frog populations
Maintain the abundance of freshwater turtle populations
Plant icon
Maintain or restore a variety of self-sustaining submerged and emergent aquatic vegetationtypes

Maintain or restore the diversity, condition and/or extent of native streamside vegetation fringing wetlands

Discourage the introduction and spread, or reduce the extent and density of undesirable/invasive plants (Sale Common)
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Maintain or enhance waterbird breeding, recruitment, foraging and sheltering opportunities
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Provide suitable physio-chemical conditions to support aquatic life

Avoid catastrophic water quality conditions (such as acid sulfate soil exposure) (Heart Morass)

Environmental values

Sale Common is one of only two remaining freshwater wetlands in the Gippsland Lakes system. It provides sheltered feeding, breeding and resting habitat for a large range of waterbirds, including the Australasian bittern.

Dowd Morass is a large, brackish wetland that regularly supports rookeries of colonial nesting waterbirds including Australian white ibis, straw-necked ibis, little black and little pied cormorants, royal spoonbills and great egrets.

Heart Morass is also a large brackish wetland, with open expanses providing shallow feeding habitat for waterbirds including black swans, Eurasian coots and a variety of ducks.

Together, the lower Latrobe wetlands function as a diverse and complementary ecological system. Colonial nesting waterbirds breed among swamp paperbark trees at Dowd Morass in spring. Migratory shorebirds feed on the mudflats that are exposed as the wetlands draw down and dry over summer. Waterfowl and fish-eating birds use openwater habitat at the wetlands year-round. The wetlands also support threatened vegetation communities including swamp scrub, brackish herbland and aquatic herbland.

Recent conditions

Climatic conditions in the lower Latrobe wetlands’ catchment varied throughout 2019–20. Total rainfall was below average, but there were still some significant rain events that increased river levels throughout winter and spring 2019,  particularly from the Latrobe River catchment, and they caused minor overbank flooding in late spring 2019 and again in  late autumn 2020. The VEWH’s entitlement for the lower Latrobe wetlands is not limited in volume, and regulator gates  may be opened opportunistically based on water height in the Latrobe River at Swing Bridge.

Heart Morass, Dowd  Morass and Sale Common were allowed to draw down in 2018–19 to allow the die-off of aquatic vegetation, promote  nutrient cycling and allow terrestrial grasses and sedges to establish. Overbank flows in late winter and early spring 2019  partly refilled the wetlands. Environmental water was subsequently delivered as required (and when salinity in the  Latrobe River estuary was not too high) to maintain water quality and habitat for aquatic and terrestrial animals, and to  support the growth and flowering of semi-aquatic vegetation. Complete and near-complete fills were achieved at Dowd  Morass and Heart Morass respectively in 2019–20, and a partial fill was achieved at Sale Common. A flushing flow was  delivered to Heart Morass in spring 2019 to export salts and sulfates. Water levels at all wetlands were drawn down  partially over summer to expose mudflats, which created feeding opportunities for wading birds and oxygenated soils to  promote seed germination. High rainfall in late April and May 2020 caused minor flooding, allowing deliveries of  freshwater to the lower Latrobe wetlands again in autumn.

Some water was retained in Dowd Morass and Sale Common to maintain habitat for Australasian bittern and other significant waterbirds that were observed at these sites during  summer. Maintaining this habitat will likely be a priority throughout 2020–21.

Traditional Owner cultural values and uses

The Gunaikurnai have had a continued connection to Gunaikurnai Country for thousands of years, including with the waterways in the Latrobe River system. For the Gunaikurnai as traditional custodians there are immense challenges to heal, protect and manage Country which has been drastically altered since colonisation. Gunaikurnai see all of Country as connected with no separation between landscapes, waterways, coasts and oceans and natural and cultural resources – the cultural landscape is interdependent.

Gunaikurnai Land and Waters Aboriginal Corporation (GLaWAC) is working with the West Gippsland CMA to determine how to express Gunaikurnai objectives for water in a way that contributes to seasonal watering proposals from the perspective of traditional custodians, with traditional knowledge.

For the Latrobe River system this has included:

  • Aboriginal Waterway Assessments to examine cultural values and uses
  • identification of primary objectives under the modified water regime
  • expression of preliminary outcomes: watering actions that recognise and promote:
    • Healthy Country
    • the importance of the Latrobe River system to the Gunaikurnai songline of Boran (pelican) and Tuk (musk duck) and their respective water quality and habitat requirements
    • waterways as meeting places
    • preliminary accommodation of water quality and management requirements of species with cultural values and uses.

GLaWAC shared with the West Gippsland CMA plant and animal species of cultural significance in and around the waterways of the Latrobe Valley, and the importance of specific watering decisions to support them.

Watering requirements to support cultural values and uses include:

  • timing of environmental watering planned in partnership with GLaWAC to support a seasonal flow regime and wet and dry periods that embody Healthy Country
  • maintaining freshwater supply to Latrobe estuary, Dowd Morass, Sale Common and Heart Morass and associated freshwater habitats. The lower Latrobe wetlands are an important resource for the Gunaikurnai
  • providing connectivity between reaches and onto floodplains to support dependent plants and animals with cultural values and uses of significance to the Gunaikurnai
  • maintaining water quality to support health of native plants and animals with cultural values and uses of significance to the Gunaikurnai.

Social, recreational and economic values and uses

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

  • water-based recreation (such as canoeing and fishing)
  • riverside recreation and amenity (such as camping, birdwatching, duck hunting and amenity for access tracks)
  • socio-economic benefits (such as commercial fishing).

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for the lower Latrobe wetlands

Potential environmental watering action

Functional watering objectives

Environmental objectives

Sale Common

Partial fill (during July to December, with top-ups as required to maintain water height above 0.3m AHD[Australian Height Datum])

Maintain a water level at 50 percent or greater (0.3m AHD) to:

  • encourage the growth and flowering of semi-aquatic plants
  • provide appropriate wetland habitat for frogs and turtles
  • provide conditions that support waterbug communities and food resources for waterbirds
  • wet key habitats within the wetland for sufficient duration to discourage invasive plants, particularly the excessive spread of giant rush

Frog iconTurtle iconPlant iconHeron icon

Fill (during August to November and maintain at full level for at least two months)1

  • Wet the outer boundaries of the wetland to support the growth and flowering of streamside and fringing wetland plants, increasing foraging opportunities for waterbirds
  • Encourage bird breeding by providing nesting habitat to wet reed beds and provide deep water next to reedbeds
  • Provide connectivity between the river and wetlands and increase habitat and feeding opportunities for frogs and turtles
Frog iconTurtle iconPlant iconHeron iconWater drop icon

Top-up (anytime, following bird breeding event if required)

  • Prolong wetting of reed beds to maintain habitat and food resources for nesting waterbirds and protect chicks from predators
Heron icon

Dowd Morass

Partial fill (during April to December, with top-ups over summer to maintain surface coverage)2

  • Provide seasonal variation in water depth throughout the wetland to support the growth and flowering of semi-aquatic plants
  • Wet vegetation and soils at middle elevations within the wetland to increase the abundance of waterbugs and other food resources for frogs, turtles and waterbirds
  • Provide connectivity between the river and wetlands and between wetlands, increasing available habitat for frogs and turtles
  • Support bird breeding (when delivered in spring/early summer following earlier fill) by maintaining wetted habitat around reed beds
Frog iconTurtle iconPlant iconHeron icon

Fill (during August to November)

  • Wet reed beds and deep water next to reedbeds to provide waterbird nesting habitat and to stimulate bird breeding
  • Wet high-elevation banks and streamside zone to support vegetation growth, creating nesting habitat for waterbirds
  • Wet vegetation and soils at higher elevations to stimulate ecosystem productivity and increase the abundance of waterbugs and other food resources for frogs, turtles and waterbirds
  • Provide connectivity between the river and wetlands and between wetlands, increasing available habitat for frogs and turtles
Frog iconTurtle iconPlant iconHeron icon

Trigger-based fill or partial fill to control salinity (any time)3

  • Dilute salt concentrations within the wetland that may be caused by king tides from Lake Wellington (likely occurring between March to May) orother sources
  • This watering action is likely to be triggered4 if electrical conductivity is rising and reaches 7,000 μS/cm
Water drop icon

Top-up (anytime, following bird breeding event if required)

  • Prolong wetting of reed beds to maintain habitat for waterbirds and protect chicks from predators, following an observed breeding event

Heron icon

Heart Morass

Partial fill (during August to December, with top-ups as required to maintain water level above -0.3 m AHD5)

  • Maintain water levels above -0.3 m AHD year-round to avoid exposing acid sulfate soils
  • Provide seasonal variation in water depth throughout the wetland to support the growth and flowering of semi-aquatic plants
  • Provide appropriate wetland fringing habitat for frogs and turtles
  • Provide conditions that support waterbug communities and food resources for frogs, turtles and waterbirds
  • Stimulate bird breeding by providing nesting habitat via inundating reed beds and deep water next to reedbeds

Frog iconTurtle iconPlant iconHeron iconWater drop icon

Partial wetland flush (during June to November)

  • Fill wetland to 0.5m AHD and allow water to flush through the wetland to export accumulated salts and sulfates
  • Allow the import and export of nutrients, dissolved organic carbon and seed dispersal between the Latrobe River and Heart Morass

Plant iconWater drop icon

Trigger-based fill or partial fill to respond to acid sulfate soil exposure or control salinity (any time)3

  • Respond to decreasing pH from the rewetting of exposed acid sulfate soils (most likely during high-wind events)
  • Dilute salt concentrations within the wetland that may be caused by king tides from Lake Wellington or other sources. This watering action is likely to be triggered6 if wetland overtopping appears likely; based on rising water levels at Lake Wellington (reaching or exceeding +0.5m AHD)
Water drop icon 

Top-up (anytime, following bird breeding event if required)

  • Prolong wetting of reed beds to maintain habitat for waterbirds and protect chicks from predators, following an observed breeding event

Heron icon

1 While a full fill is the target, if salinity in the Latrobe River is too high a partial fill may be provided instead, helping to achieve some of the listed functional watering actions. This is most likely to eventuate under drought conditions.

2 Timing of this flow changes depending on the scenario. An extended partial fill may be required under a drought scenario, however under dry to wet scenarios, partial fills either side of the full fill over late winter and spring are preferred. Top-ups over summer are unlikely under a drought scenario, as reduced flow in the Latrobe River is likely to increase salinity levels beyond a tolerable limit for wetland filling.

3 Trigger-based events may override other planned watering actions if required, to maintain conditions at the site.

4 If salinity level in the Latrobe River exceeds 15,000 μS/cm, a fill or partial fill will not be provided.

5 Maintaining the water level above -0.3m AHD is a high priority, to avoid exposing acid sulfate soils.

6 If the salinity level in the Latrobe River exceeds 10,000 μS/cm, a fill or partial fill will not be provided.

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 longerterm 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 indeveloping the Latrobe system seasonal watering proposal

Partner and stakeholder engagement
  • Greening Australia
  • Latrobe Valley Field Naturalists
  • Native Fish Australia
  • Parks Victoria
  • Gippsland Water
  • Department of Land, Environment, Water and Planning (Latrobe Valley Regional Water Study)
  • Department of Land, Environment, Water and Planning (Waterways and Catchments)
  • East Gippsland CMA
  • Field and Game Australia (Heart Morass)
  • Individual landholders
  • Port of Sale Heritage River Cruises
  • Field and Game Australia (Dowd Morass and Sale Common)
  • VRFish
  • Gunaikurnai Land and Waters Aboriginal Corporation

Page last updated: 24/07/20