VEWH - Central Murray wetlands

The central Murray wetlands are almost wholly contained within the Torrumbarry Irrigation Area and are all wetlands of regional or international significance. The area has experienced dramatic changes since European settlement with the construction of levees, roads and channels. Most of the wetlands are now cut off from natural flow paths and are rarely inundated by natural floods. They rely on water for the environment to maintain their ecological character and health.

Nine of the central Murray wetlands can receive water for the environment from permanent infrastructure: Lake Cullen, Hird Swamp, Johnson Swamp, Round Lake, McDonalds Swamp, Lake Elizabeth, Lake Murphy, Richardsons Lagoon and the Wirra-Lo wetland complex. Temporary pumps may be used to deliver water for the environment from the River Murray to some semi-permanent wetlands in the Guttrum and Benwell forests.

System map

Environmental watering objectives in the Central Murray wetlands

Restore the population of critically endangered Murray hardyhead 

Maintain or increase the population of common, small-bodied native fish (such as carp gudgeon and flat-headed gudgeon)

Restore populations of endangered growling grass frog 

Maintain the populations of common native frogs (such as barking marsh frog, Peron’s tree frog and spotted grass frog)

Supply carbon to Pyramid Creek to boost the riverine foodweb

Maintain the population of native turtle species (such as the Murray River turtle and the common long-necked turtle)

Restore and maintain the health of riparian trees (such as river red gum and black box) 

Restore and maintain mudflat vegetation communities (such as tall marsh, herblands, rushes and sedges) 

Restore and maintain native aquatic vegetation species (such as tassel, milfoil and pondweed) 

Reduce the extent and density of invasive plant species 

Support a mosaic of wetland plant communities across the region

Provide habitat for waterbird nesting, feeding and breeding for a variety of feeding guilds, including threatened species (such as Australasian bittern, little bittern and brolga)

Aboriginal environmental outcomes

Watering is planned to be delivered in partnership with Traditional Owners and achieve Aboriginal environmental outcomes

Environmental values

The wetlands in the central Murray system support vulnerable or endangered species including the Australasian bittern, Murray hardyhead, Australian painted snipe and growling grass frog. The wetlands provide habitat for many threatened and endangered bird species (including the eastern great egret and white-bellied sea eagle) listed under legislation and international agreements. Lake Cullen, Hird Swamp and Johnson Swamp are internationally recognised under the Ramsar Convention, while the other wetlands in the central Murray system have bioregional significance.

Recent conditions

Northern Victoria experienced drier and warmer conditions than average across 2018–19, with inflows to major storages tracking between dry to below average. Water for the environment was delivered to seven of the central Murray wetlands in 2018–19, as planned under a dry climate scenario.

In Round Lake and Lake Elizabeth, water for the environment was periodically used to maintain salinity within the target range for endangered Murray hardyhead, which were stocked in 2018 and 2016. Sampling at Lake Elizabeth in autumn 2018 found 24 Murray hardyhead (indicating successful recruitment, as the fish live for less than two years) and an additional 300 Murray hardyhead were released in Round Lake in October 2018 as part of a statewide translocation project.

Lake Cullen received water for the environment in spring 2018, which is the first time it has been watered independently of the Avoca Marshes. Until recently, it was thought that groundwater interactions forced saline water into the marshes when Lake Cullen was full. Recent investigations confirmed that this is not the case, which means water for the environment can be used as needed (irrespective of water levels in the Avoca Marshes) to support more environmental objectives in the lake. A waterbird survey conducted at Lake Cullen after the spring 2018 watering event recorded over 29,000 individual waterbirds, representing 60 waterbird species. Further monitoring was undertaken by Barapa Barapa and Wamba Wemba Traditional Owners in winter 2019.

Lignum Swamp North and Brolga Swamp, within the Wirra- Lo wetland complex, received water for the environment in 2018–19. Six frog species including the endangered growling grass frog were recorded at the wetland throughout spring/summer.

Water for the environment was also delivered to McDonalds Swamp, Lake Murphy and Johnson Swamp in 2018–19, to promote vegetation growth to support feeding and breeding for birds.

Scope of environmental watering

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

Potential environmental watering action	Functional watering objective	Environmental objective
Round Lake (top-ups as required to maintain water quality targets)	Maintain salinity within 25,000–40,000 EC1 to support suitable habitat and breeding conditions for Murray hardyhead and growing conditions for submerged aquatic plants
Lake Elizabeth (top-ups as required to maintain water quality targets)	Maintain salinity within 25,000–40,000 EC1 to support suitable habitat and breeding conditions for Murray hardyhead and growing conditions for submerged aquatic plants Provide permanent water as habitat for waterbirds
Wirra-Lo wetland complex – Duck Creek North, Duck Creek South, Lignum Swamp North and Brolga Swamp (fill in spring)	Maintain the health of open woodland vegetation, lignum and other aquatic vegetation Provide feeding and breeding habitat for growling grass frog and other frog species Provide foraging habitat for shallow-wading waterbirds and mudflat specialists Provide refuge and recruitment sites for freshwater turtles
Wirra-Lo wetland complex – Red Gum Swamp (fill in spring)	Maintain the health of existing red gum trees
Wirra-Lo wetland complex – Bittern West and Bittern East wetlands (partial fill in spring)	Support the growth of newly-established reed beds to create nesting habitat for Australasian bittern
Guttrum Forest (fill in spring and autumn, with top-ups in summer if required to support waterbird breeding)	Inundate the existing adult river red gums to support their growth and drown river red gum saplings in the open-water habitat Promote the growth and re-establishment of aquatic and tall marsh vegetation Maintain the depth of the wetland to support waterbird feeding and breeding
Johnson Swamp (fill in spring – with through-flow to Pyramid Creek, with top-ups in summer/autumn to support bird breeding if required²)	Promote waterbird breeding and feeding Restrict the growth of tall marsh vegetation by preventing otherwise favourable warm, shallow-water conditions Promote the growth of aquatic herbland species Provide refuge and recruitment sites for freshwater turtles Provide carbon and nutrients to Pyramid Creek
McDonalds Swamp (partial fill in autumn)	Promote the growth of planted and naturally recruited river red gums Support the germination of aquatic vegetation Promote winter feeding conditions for waterbirds and frogs
Lake Cullen (top-up in spring, and as required to support waterbird breeding²)	Maintain waterbird refuge Promote the growth and recruitment of submerged aquatic plants Maintain water levels to support waterbird breeding
Wetland drying
Lake Murphy, Hird Swamp and Richardsons Lagoon will not be actively watered in 2019–20	Prevent drowning existing trees in the bed of wetlands Promote herbland species and establish fringing vegetation around the edge of each wetland Reduce the extent of water-dependent invasive species (such as cumbungi) Allow for oxidation of the soil (Richardsons Lagoon)

¹ EC stands for electrical conductivity, which is a measure of water salinity.

² Top-ups to support waterbird breeding may occur if species of high conservation significance display breeding behaviour or nesting activity, or if large numbers of waterbirds have nests with live chicks.

Engagement

Table 2 shows the partners, stakeholder organisations and individuals with which North Central CMA engaged when preparing the central 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 North Central Regional Catchment Strategy and the North Central Waterway Strategy.

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

Partner and stakeholder engagement
Individual community members Individual landholders Forestry businesses Apiary licensees Campaspe Shire Council Commonwealth Environmental Water Office Department of Environment, Land, Water and Planning Forestry Corporation of New South Wales Goulburn-Murray Water Loddon Shire Council Murray-Darling Basin Authority Parks Victoria Swan Hill Rural City Council VicForests Victorian Environmental Water Holder BirdLife Australia Field and Game Australia Barapa Barapa Traditional Owners Dja Dja Wurrung Clans Aboriginal Corporation Wamba Wemba Traditional Owners Yorta Yorta Nation Aboriginal Corporation

Partner and stakeholder engagement

Individual community members
Individual landholders
Forestry businesses
Apiary licensees
Campaspe Shire Council
Commonwealth Environmental Water Office
Department of Environment, Land, Water and Planning
Forestry Corporation of New South Wales
Goulburn-Murray Water
Loddon Shire Council
Murray-Darling Basin Authority
Parks Victoria
Swan Hill Rural City Council
VicForests
Victorian Environmental Water Holder
BirdLife Australia
Field and Game Australia
Barapa Barapa Traditional Owners
Dja Dja Wurrung Clans
Aboriginal Corporation
Wamba Wemba Traditional Owners
Yorta Yorta Nation Aboriginal Corporation

Page last updated: 10/03/20