Lower Murray wetlands

The lower Murray wetlands are dispersed across the Murray River floodplain between Swan Hill and the South Australian border. The system includes a myriad of interconnected creeks, wetlands and floodplains that are ecologically important and reflect the natural character and attributes of the floodplain. While the number of wetlands across the lower Murray region are in their hundreds, about 54 of these have received water for the environment to date.

Regulation and diversion of Murray River flows have substantially reduced the frequency and duration of the high river flows that would naturally water the lower Murray wetlands. This change to the water regime has been exacerbated by climate change and has reduced the variety and condition of environmental values associated with billabongs and other floodplain habitats.

Water for the environment can be delivered to some wetlands in the region through direct pumping from the Murray River and/or use of irrigation supply infrastructure. Most wetlands that receive environmental flows can be managed independently of each other.

Some wetlands within the lower Murray region can receive water through weir pool manipulation and regulator operation, for improved environmental outcomes. However, because they do not receive held environmental water, they are not specified under this plan. Details of the environmental objectives associated with those wetlands can be found in the Mallee CMA’s Seasonal Watering Proposal for the Lower Murray Wetlands 2020–21.

System map

Environmental watering objectives in the Lower Murray wetlands

Maintain and/or increase populations of native fish in permanent wetlands

Maintain and/or grow populations of native frogs including the endangered growling grass frog

Increase the diversity, extent and abundance of wetland plants Improve the condition of river red gums, black box and lignum

Provide feeding and breeding habitat for a range of waterbird species including threatened and migratory species and colonial nesting species (such as egrets)

Environmental values

The lower Murray wetlands are comprised of multiple wetlands, creeks and billabongs. Depending on their location in the landscape, interactions with groundwater and their management history, the wetlands may be permanent or temporary, freshwater or saline. Differences in water regime and water quality between the wetlands provide a range of habitats for plants and animals. For example, permanent, saline wetlands (such as Koorlong Lake) provide vital habitat for the endangered Murray hardyhead fish. Ephemeral wetlands support different ecological processes in their wet and dry phases. During the wet phase, they provide short-term boom periods when river red gum trees and wetland plants grow, spread and provide habitat for aquatic animals (such as waterbugs, birds, frogs and in some cases fish). During the dry phase, sediments are exposed to the air (which is important for carbon and nutrient cycles), and terrestrial plants grow and complete life cycles.

Traditional Owner cultural values and uses

Watering of the lower Murray wetlands supports values such as traditional food sources and medicines, important species and provides opportunities for teaching, learning and storytelling.

Mallee CMA has met with the First People of Millewa- Mallee Aboriginal Corporation (representing Latji Latji, Ngintait, Nyeri Nyeri and Wergaia Traditional Owners), and representatives from Tati Tati, Weki Weki, Wadi Wadi, Gilby Corporation and Munutunga Elders. Discussions covered a range of options for how environmental flows can be delivered in 2020–2021 and what the traditional ecological needs were in the current climate. Elders participated in planning and prioritisation processes on Country important to them and relationships with the Mallee CMA were strengthened. The values, knowledge and concerns raised through these discussions have supported Mallee CMA’s planning for wetland watering across the lower Murray region.Waterway managers are seeking opportunities to increase the involvement of Traditional Owners in environmental water planning and management. 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 1 with an icon.

Watering planned and/or delivered in partnership with Traditional Owners to support Aboriginal cultural values and uses

Robertson Creek is an area of high cultural significance that is being degraded as vegetation dies from lack of water and wind erodes the landscape. The First People of the Millewa Mallee Aboriginal Corporation are undertaking a program of restoration and protection work at the site. To complement the protection and restoration objectives, environmental water is planned to be delivered under all scenarios except drought, to improve the canopy cover of black box trees and to regenerate understory vegetation along Robertson Creek. In turn, the improved vegetation health will provide wind protection to the landscape alongside Robertson Creek.

Margooya Floodplain Wetland is a new site to be incorporated in the lower Murray wetlands environmental watering program in 2020-21. It is a small wetland to the north-east of Margooya Lagoon and the area is known to be of significant Indigenous cultural value. The main lagoon can receive water using existing infrastructure, but the surrounding floodplain is showing signs of drought stress. Mallee CMA has worked closely with the local Aboriginal community to identify potential watering actions to preserve and enhance cultural values at the site, including availability of traditional foods and medicines and preservation of an ecosystem and landscape used for ceremonies and featuring in song lines.

Social, recreational and economic values and uses

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

water-based recreation (such as canoeing, fishing, swimming and yabbying)
riverside recreation and amenity (such as bushwalking, photography, running, yoga, geocaching, camping, birdwatching and four-wheel driving)
community events and tourism (such as Parks Victoria's 'Junior Ranger' school holiday programs including bushwalking, birdwatching and bug hunting, citizen science projects (frogs and bats), community education and engagement programs, and tourists visiting the wetlands)
socio-economic benefits (such as local businesses).

Recent conditions

The lower Murray region had below-average rainfall and above-average temperatures throughout 2019–20. ainfall in some areas was the lowest recorded across two consecutive years. Flow in the Murray River was not sufficient to connect any wetlands on the lower Murray floodplain, and there was very limited run-off from local catchments.

In 2019–20, environmental water was delivered to 10 lower Murray wetlands that were identified as a high priority for environmental watering under a dry scenario. Most deliveries were in spring to maintain native vegetation, provide refuges for fish and waterbirds and maintain key ecosystem functions. Top-ups were provided to Lake Hawthorn, Brickworks Billabong and Koorlong Lake during summer and autumn to protect habitat for endangered Murray hardyhead.

During 2019–20, the Mallee CMA monitored water levels at wetlands that it had identified as important refuge habitats for native fish and frogs. Continued surveillance of refuge habitats will be a high priority in 2020–21.

Scope of environmental watering

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

Potential environmental watering action	Functional watering objective	Environmental objectives
Wetland watering
Brickworks Billabong (fill in spring, with top-ups over summer/autumn as required)	Fill in spring to 34.0 m AHD (Australian Height Datum) to wet and grow ruppia to provide nursery habitat for Murray hardyhead, and provide high levels of aquatic productivity Allow natural recession of a maximum 1 m in late summer/autumn (to 33.0 m AHD) to provide shallow-water habitat and expose the mudflats to support foraging and resting of small waders
Lake Hawthorn (top up in spring/summer/autumn as required)	Fill the wetland to 33.3 m AHD to encourage the germination and growth of ruppia to provide nursery habitat for Murray hardyhead and visitation by shorebirds Maintain water levels within a 30 cm range to provide resources for shorebirds and to maintain the Murray hardyhead population
Koorlong Lake (top up in spring/summer/autumn as required)	Fill the wetland to 38.0 m AHD in spring to support the growth of ruppia to provide nursery habitat for Murray hardyhead and provide high levels of aquatic productivity Maintain water levels within a 30 cm range to provide resources for shorebirds and to maintain the Murray hardyhead population
Margooya Floodplain Wetland (fill in autumn)	Wet the floodplain to improve the health of the river red gum
Robertson Creek (fill in spring)	Fill the creek to wet the vegetation on the creek bed, banks and terraces to maintain the health and persistence of fringing black box and lignum communities
Neds Corner Woolshed (through-flow in spring)	Slow through-flow to allow seepage and fill deeper holes, to maintain the health of the fringing red gum vegetation communities and waterdependent species
Bidgee lagoons (fill in spring)	Fill the wetlands to maintain the health of river red gum communities, promote emergent vegetation communities and provide habitat for waterbirds
Robertson Wetland (west) (partial fill in spring)	Partially fill the wetland to promote the growth of cane grass and lignum and provide habitat for waterbirds
Fishers lagoons (fill in spring)	Fill the wetland to maintain the health of fringing river red gum communities
Burra Creek South proper (fill in spring)	Fill the creek line to maintain the fringing river red gum communities
Lake Powell (fill in spring)	Fill the lake to maintain the river red gum communities Improve nesting habitat for waterbirds in flooded trees bordering the lake
Lake Carpul (fill in spring)	Fill the lakes to maintain the river red gum communities Improve nesting habitat for waterbirds in flooded trees bordering the lake

Engagement

Table 2 shows the partners and stakeholder organisations with which Mallee CMA engaged when preparing the lower Murray 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 Mallee Regional Catchment Strategy and the Mallee Waterway Strategy

Table 2 Partners and stakeholders engaged in developing the lower Murray wetlands seasonal watering proposal

Partner and stakeholder engagement
Cabarita Inc. Community members on the Mallee CMA Land and Water Advisory Committee Local Landcare groups Mid-Murray Field Naturalists Goulburn-Murray Water Parks Victoria Department of Environment Land, Water and Planning (Fire Forest and Regions) Department of Environment Land, Water and Planning (Water and Catchments) Lower Murray Water Loddon Mallee Waste and Resource Recovery Group Mildura Rural City Council Swan Hill Rural City Council Trust for Nature Local landowner Sunraysia Apiarist Association Mallee Tours Murray Offroad Adventures Visit Mildura Wildside Outdoors Birdlife Mildura Four-wheel drive club Mildura Information Centre Sunraysia Bushwalkers Mallee CMA Land and Water Advisory Committee Arthur Rylah Institute (Department of Environment, Land, Water and Planning) Robinvale Elders and communties First People of the Millewa-Mallee Aboriginal Corporation

Partner and stakeholder engagement

Cabarita Inc.
Community members on the Mallee CMA Land and Water Advisory Committee
Local Landcare groups
Mid-Murray Field Naturalists
Goulburn-Murray Water
Parks Victoria
Department of Environment Land, Water and Planning (Fire Forest and Regions)
Department of Environment Land, Water and Planning (Water and Catchments)
Lower Murray Water
Loddon Mallee Waste and Resource Recovery Group
Mildura Rural City Council
Swan Hill Rural City Council
Trust for Nature
Local landowner
Sunraysia Apiarist Association
Mallee Tours
Murray Offroad Adventures
Visit Mildura
Wildside Outdoors
Birdlife Mildura
Four-wheel drive club
Mildura Information Centre
Sunraysia Bushwalkers
Mallee CMA Land and Water Advisory Committee
Arthur Rylah Institute (Department of Environment, Land, Water and Planning)
Robinvale Elders and communties
First People of the Millewa-Mallee Aboriginal Corporation

Page last updated: 22/01/21