Lower Latrobe wetlands

The lower Latrobe wetlands (Dowd Morass, Heart Morass and Sale Common) are an important component of the internationally recognised Gippsland Lakes Ramsar site and provide habitat for waterbirds of state, national and international conservation significance. The wetlands are located on the floodplain of Durt-Yowan (Latrobe River) between its confluence with Carran Carran (Thomson River), and they form part of the Gippsland Lakes system.

River regulation and water extraction from the Latrobe, Thomson and Macalister rivers have reduced the frequency of small and medium-sized floods that naturally wet the lower Latrobe wetlands. The construction of levees and drains and the 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.

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

Enhance waterbird breeding, recruitment, foraging and sheltering opportunities

Provide suitable physio-chemical conditions to support aquatic life

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

Maintain or restore a variety of self-sustaining submerged and emergent aquatic vegetation types

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)

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 diverse 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 various duck species. 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 the summer. Waterfowl and fish- eating birds use open-water habitat at the wetlands year-round. The wetlands also support threatened vegetation communities, including swamp scrub, brackish herbland and aquatic herbland.

Traditional Owner cultural values and uses

The lower Latrobe wetlands are a place of spiritual and cultural connection for the Gunaikurnai people. Over many thousands of years, customs and lore have been passed orally between generations about the cultural values and uses of the wetlands and their importance to all Gunaikurnai people. The wetlands are on the lands of the Brayakaulung clan of the Gunaikurnai.

For the Gunaikurnai, the overarching objective for the wetlands is to provide and maintain healthy Country. Healthy Country includes the importance of place and the health of the entire ecosystem, including maintaining water quality, controlling pest species and maintaining a natural, seasonal flow regime and overbank flood events.

Environmental objectives for the delivery of water for the environment for the lower Latrobe wetlands should take a cultural landscape approach.

Watering requirements to support cultural values and uses include:

timing the delivery of water for the environment planned in partnership with the Gunaikurnai Land and Waters Aboriginal Corporation (GLaWAC) to support a seasonal flow regime and wet and dry periods that embody healthy Country
maintaining freshwater supply to the Durt-Yowan (Latrobe River) estuary, Dowd Morass, Sale Common and Heart Morass and associated freshwater habitats
providing connectivity between reaches and onto floodplains and maintaining water quality to support cultural values and uses of significance to the Gunaikurnai.

The lower Latrobe wetlands support many keystone species important to the Gunaikurnai. Borun (pelican) and Tuk (musk duck) are the father and mother in the Gunaikurnai creation story. If Borun and Tuk are living and breeding at the wetlands, it is a sign that Country is healthy. If they are not, flows should be provided to promote required habitat and ecosystem services.

Other birds are important for woorngan (hunting) and food, including nalbong (water hens), gidai (black swans), boyangs (eggs) and koortgan (ducks except for tuk). Gidai require submerged and softer emergent vegetation to make nest mounds, placing them on a small island or floating them in deeper water. Gidai breed in late Winter to early Spring after the water level rises. Actions that fill the large wetlands and support the growth of loombrak (water ribbon) and submerged aquatic plants will support gidai. Ensuring that the lower wetlands and floodplain depressions (for example, billabongs) receive freshwater flows in Winter/Spring will provide the conditions for submerged and emergent aquatic plants to grow and provide food and nesting materials for the waterbirds.

GLaWAC is developing a vision for the wetlands that aligns with the Gunaikurnai Whole-of-Country Plan. Key aspects of the vision include:

healthy Country: reflecting the spiritual and cultural values of the Gunaikurnai custodians; healthy Country contributes to the wellbeing of the Gunaikurnai
water access: access to water is crucial for many cultural values, including identity and relational values, future economic values and place values, among many others. Access to water, through ownership or management, means that water is made available to the Gunaikurnai on the Latrobe and Thomson systems to provide freshwater to the wetlands. Every effort should be made to maintain freshwater-dependent values, which in turn deliver cultural values
cultural and economic use: returning to cultural practices and Gunaikurnai-informed management at the lower Latrobe wetlands is key to returning to a more freshwater habitat for cultural uses and cultural species. It will also provide for water- based tourism, cultural education and ecotourism (camping) experiences
connection: GLaWAC takes its responsibility to work closely with the people it represents on management decisions concerning Country and the health of Country very seriously. Gunaikurnai cultural obligations reflect Gunaikurnai views on healthy Country and, in turn, help the Gunaikurnai continue their ongoing connection to the land and waters of Country
climate change: the Gunaikurnai have cared for Country for thousands upon thousands of years through many cycles
of climatic change, and they understand how to manage the landscape as it too changes. When cared for using traditional knowledge, Country can be healed. Mitigation of climate change impacts affecting the lakes, rivers and other waterways of the lower Latrobe wetlands can be effective with resources and empowerment provided to the Gunaikurnai.

Increasing the involvement of Traditional Owners in environmental flows 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 2022 Water is Life: Traditional Owner Access to Water Roadmap 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 2.2.3 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

GLaWAC and West Gippsland CMA are exploring opportunities to align environmental flows with Gunaikurnai outcomes in the lower Latrobe wetlands. In 2023-24, a Gunaikurnai cultural event is planned at Dowd Morass. This event will be jointly managed with WGCMA and will coincide with delivery of water for the environment. The timing of the event will be decided by GLaWAC, after some water quality and fish monitoring.

In early 2023, the West Gippsland CMA met with GLaWAC to discuss 2023-24 environmental watering priorities in the lower Latrobe wetlands, with further engagement planned in the 2023-2024 water year.

Social, recreational and economic values and uses

In planning the potential environmental watering actions in Table 2.2.3, 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 birdwatching, bushwalking, camping and duck hunting)
socioeconomic benefits (such as commercial eel and carp fishing and tourism).

Scope of environmental watering

The term ‘environmental watering’ refers to the active delivery of water for the environment to support particular environmental objectives by altering the flow in a river or the water level in a wetland. While other terms are also used to describe the delivery of water for the environment, ‘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 2.2.3 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 2.2.3 Potential environmental watering actions, expected watering effects and associated environmental objectives for the lower Latrobe wetlands

Potential environmental watering action	Expected watering effects	Environmental objectives
Sale Common
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
Partial fill (in July to August¹ with top-ups as required to maintain water depth of at least 0.3 m AHD and surface coverage year-round)	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
Fill (with top-ups as required during August to November, to maintain water depth of 0.4 m AHD for two months)	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 and turtle breeding by providing nesting habitat Provide connectivity between the river and wetlands and increase habitat and feeding opportunities for frogs and turtles
Trigger-based fill or top-up to 0.5 m AHD (during December to January) Trigger: requirement to drown out invasive vegetation	Wet key habitats within the wetland for a sufficient duration to discourage invasive plants, particularly the excessive spread of giant rush
Partial drawdown (during December to March)	Oxygenate sediments to enable aquatic vegetation germination and recruitment Provide water level fluctuations for emergent vegetation reproduction and expansion (particularly swamp scrub and tall marsh) Break down organic matter and promote nutrient cycling Expose mudflats and create shallows to facilitate waterbird foraging
Dowd Morass
Top-up (any time, following bird breeding event if required)	Prolong wetting of reed beds to maintain habitat and food resources for waterbirds and protect chicks from predators, following an observed breeding event
Fill to control salinity (anytime)	Dilute salt concentrations within the wetland that may be caused by king tides from Lake Wellington (likely occurring between March to May) or other sources This watering action is likely to be triggered1 if electrical conductivity is rising and reaches 7,000 μS/cm
Partial fill (with top-ups as required to maintain a water depth of 0.3 m AHD during July to December 2023 and April to June 2024²)	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
Fill (with top-ups as required to maintain water depth of 0.6 m AHD during August to November)	Wet reed beds and deep water next to reedbeds to provide waterbird nesting habitat and stimulate bird breeding Wet high-elevation banks and the 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 and food resources for frogs and turtles Reduce the impact of saltwater incursion from Lake Wellington
Partial drawdown (during January to March)	Oxygenate sediments to enable aquatic vegetation germination and recruitment Provide water level fluctuations for emergent vegetation reproduction and expansion (particularly swamp scrub and tall marsh) Break down organic matter and promote nutrient cycling Expose mudflats and create shallows to facilitate waterbird foraging
Heart Morass
Top-up to permanently maintain water level above -0.3 m AHD (anytime)	Minimise the risk of acid sulfate soils developing by keeping known high- risk areas wet 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 triggered³ if wetland overtopping appears likely; based on rising water levels at Lake Wellington (reaching or exceeding +0.5m AHD)
Top-up (anytime, following bird breeding event if required)	Prolong wetting of reed beds to maintain habitat and food resources for waterbirds and protect chicks from predators, following an observed breeding event
Fill and partial flushing flow (during July to November⁴)	Wet high-elevation banks and streamside zone to support vegetation growth, create nesting and foraging habitat for waterbirds and provide food resources for terrestrial birds Provide connectivity between the river and wetlands and between wetlands, increasing available habitat and providing food resources for frogs and turtles Export accumulated salts and sulfates and transport nutrients, dissolved organic carbon and seeds between the Latrobe River and Heart Morass
Partial fill (with top-ups as required to maintain a minimum water depth of 0.3 m AHD during August to December¹)	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
Partial drawdown (during January to March)	Oxygenate sediments to enable aquatic vegetation germination and recruitment Provide water level fluctuations for emergent vegetation reproduction and expansion (particularly swamp scrub and tall marsh) Break down organic matter and promote nutrient cycling Expose mudflats and create shallows to facilitate waterbird foraging

¹ If salinity level in the Latrobe River exceeds 15,000 μS/cm, a fill will not be provided.

² This is the likely timing in the drought scenario. In the average or wet scenarios, a fill event may occur during this period, as detailed in Table 2.2.4.

³ If the salinity level in the Latrobe River exceeds 10,000 μS/cm, a top-up will not be provided.

⁴ If a partial flushing flow is not possible until the end of November, top-ups will be provided to maintain a fill with a minimum water depth of 0.5 m AHD.

Page last updated: 01/07/22