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The lower Murray wetlands are found across the floodplain of the River Murray between Swan Hill and the South Australian border (Figure 5.2.5. The system includes a myriad of interconnected creeks, wetlands and floodplains that are ecologically important and reflect the natural character and attributes of the River Murray floodplain. While the number of wetlands across the lower Murray region are undefined, 66 of them are considered in the environmental watering program, and 54 of these have received water for the environment to date.

The wetlands of the lower Murray wetlands system hold significance for Traditional Owners and their Nations. For thousands of years, the wetlands provided resources (such as food and materials) to the Latji Latji, Wadi Wadi, Dadi Dadi and Wamba Wemba people. There is currently no Registered Aboriginal Party for the lower Murray wetlands. The Mallee CMA involves the region's Aboriginal communities in water management through the Aboriginal Reference Group, which includes First Peoples of the Millewa-Mallee, Wadi Wadi and Tati Tati Traditional Owners groups.

Cowanna and Brickworks billabongs are nationally significant wetlands located at Merbein Common, next to the River Murray near Mildura. Merbein Common has been identified as a priority for investment under Water for Victoria. Investment to improve walking, cycling and canoeing facilities at Merbein Common complements the success of providing environmental flows at Cowanna and Brickworks billabongs.

System map

Environmental watering objectives in the Lower Murray wetlands

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Improve the condition of river red gums, black box and lignum to provide habitat for large terrestrial animals (such as lace monitors and bats)
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Provide feeding and breeding habitat for a range of waterbird species including threatened and migratory species and colonial species (such as egrets)
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Improve water quality and increase habitat for fish
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Increase the diversity, extent and abundance of wetland plants

Environmental values

The lower Murray wetlands are comprised of multiple wetlands, creeks and billabongs on the floodplain of the River Murray. 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 Brickworks Billabong) provide vital habitat for the endangered Murray hardyhead fish. Ephemeral wetlands provide important habitat and 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 aerate and oxygen is replaced, and terrestrial plants grow and complete life cycles.

Social and economic values

There are several irrigation districts in the Sunraysia area that are supplied by the River Murray and contribute significant wealth to the local economy. Camping, fishing and other water-based recreational activities are popular along the River Murray including at some wetlands in the lower Murray system. Waterbirds attract birdwatchers throughout the year and duck hunting is allowed during declared seasons.

Conditions 2018

Major floods in spring 2016 provided natural inflows to most of the floodplain wetlands that are on lower elevations of the River Murray floodplain. Broad, landscape-scale watering last occurred in summer 2010–11. Before the peak of the flood arrived, several small earthen levees that were built by Mallee CMA to contain environmental water that was pumped into wetlands in previous years were cut to allow floodwater to pass between wetlands. The natural flood met the environmental water objectives for the lower Murray wetlands, and there was no need to deliver environmental water to the system in the first half of 2016–17.

The floods prompted a boom in productivity and growth for most wetlands and provided welcome relief for sites that are heavily affected by salinity. Despite the size of the flood, not all wetlands received flows. Some wetlands at higher elevations and wetlands that are disconnected from the floodplain by levees or road infrastructure remained dry. In March 2017, environmental water was delivered to Lake Heywood to augment natural inflows and enable watering of Little Heywood Lake, which did not received natural inflows in spring.

Scope of environmental watering

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

Potential environmental watering

Environmental objectives

Wetland watering

Brickworks Billabong (spring, autumn and top-ups as required to maintain water quality targets and minimum water level)

  • Maintain and improve the condition of aquatic vegetation and water quality for Murray hardyhead

Cardross Lakes (partial fill as needed to maintain water-quality targets and minimum water level)

Lake Koorlong (partial fill as needed to maintain water-quality targets and minimum water level)

Lock 15 wetlands (fill or partial fill year-round)

  • Improve the productivity of connected riparian zones and wetlands
  • Rehabilitate floodplain productivity to maintain resident populations of terrestrial animals including carpet python and insectivorous bats
  • Contribute to the carbon requirements of the River Murray channel ecosystem

Lake Hawthorn (partial fill in spring or as required to maintain water at the minimum level)

  • Reintroduce saline marsh habitat, particularly Ruppia
  • Provide habitat for shorebirds

Nyah Floodplain (fill in spring/summer)

  • Improve condition and structure of wetland vegetation
  • Provide seasonal feeding and reproductive opportunities for native fish
  • Provide breeding habitat for waterbirds including colonial nesting species
  • Rehabilitate floodplain productivity to maintain resident populations of terrestrial animals including carpet pythons, sugar gliders and grey-crowned babblers

Vinifera Floodplain (fill in spring/summer)

Burra Creek North (fill in winter/spring)

  • Rehabilitate seasonal connectivity along Burra Creek
  • Improve the health and structure of vegetation
  • Stimulate the growth of emergent and semi-emergent aquatic vegetation

Burra Creek South (fill in winter/spring)

Burra Creek South Proper (fill in winter/spring)

Little Heywood Lake (fill in winter/spring)

  • Maintain black box woodland
  • Provide shallow water habitat for waterbirds

Neds Corner East and Central (fill in spring)

  • Provide breeding and roosting habitat for colonial waterbirds

J1 Creek (fill in winter/spring)

  • Maintain and improve the health of river red gum, black box and lignum

Yungera Wetland (fill in winter/spring)

Carina Bend Wetlands (fill in winter/spring)

  • Improve the condition of mature river red gum
  • Provide aquatic habitat to support fish and frogs
  • Provide habitat for waterfowl

Planigale Wetland (fill in winter/spring)

  • Promote the growth of vegetation that aligns with the intermittent swampy woodland, lignum swampy woodland and riverine chenopod ecological vegetation classes
  • Improve habitat for mammals and reptiles
  • Support growling grass frogs

Old Homestead Wetland (fill in winter/spring)

  • Promote growth of vegetation that aligns with the intermittent swampy woodland, lignum swampy woodland and riverine chenopod ecological vegetation classes

Woolshed Creek (fill in winter/spring)

  • Improve the condition of woodland vegetation
  • Improve habitat for mammals and reptiles
  • Support growling grass frogs

Inlet Creek (Karadoc Swamp) (fill in winter)

  • Improve the condition of mature black box trees
  • Provide habitat to support frogs and fish
  • Provide habitat for waterbirds

Bullock Swamp (fill in winter/spring)

  • Provide freshwater inflows and flushing flows to reduce salinity levels and improve the condition and diversity of wetland vegetation
  • Improve ecological function

Butlers Creek/Ducksfoot Lagoon (fill in spring/summer)

  • Provide feeding habitat for waterbirds
  • Control noogoora burr

Cowanna Billabong (fill in winter/spring)

  • Increase wetland productivity
  • Provide opportunities for fish to move between wetlands and the River Murray

Margooya Lagoon (fill in winter/spring)

Improve the condition of river red gums

Improve the native fish assemblage of the lagoon

Rehabilitate submerged aquatic vegetation in the open-water areas of the wetland

Liparoo East (fill in winter/spring)

  • Improve the condition of the lignum swampy woodland vegetation community and provide habitat for waterbird breeding

Liparoo West (fill in winter)

Sandilong Creek (fill in spring/summer)

  • Support catfish recruitment
  • Maintain terrestrial vegetation

Keera Wetland 1 (fill in spring)

  • Promote the growth of vegetation that aligns with the intermittent swampy woodland, lignum shrubland and lignum swampy woodland Keera Wetland 2 (fill in spring) ecological vegetation classes

Keera Wetland 2 (fill in spring)

Wetland drying

Kings Billabong, Bridge Creek, Heywood Lake, Lakes Powell and Carpul, Sandilong Billabong

  • These wetlands will not be actively watered in 2017-18
  • Drying will support a wide range of wetland-dependent birds and animals and to promote the growth and establishment of vegetation in and surrounding the wetland

Risk management

In preparing its seasonal watering proposal, Mallee CMA considered and assessed the risks of environmental watering and identified mitigation strategies. Program partners continually reassess risks and mitigation actions throughout the water year

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
  • Commonwealth Environmental Water Office 
  • Department of Environment, Land, Water and Planning 
  • Environmental groups (Trust for Nature, Nyah and Districts Action Group, Nyah and Districts Weed Warriors, Sustainable Living in the Mallee, Mallee Fowl Recovery Group, Mid-Murray Field Naturalists) 
  • Four friends groups 
  • Goulburn-Murray Water 
  • Lake Lascelles Committee 
  • Lake Tchum Committee 
  • 25 Landcare groups 
  • Lower Murray Water 
  • Mallee Aboriginal Reference Group 
  • Mallee CMA Water Technical Advisory Committee (an advisory group to Mallee CMA comprising community members) 
  • Mallee District Aboriginal Services 
  • Meringur Historical Society 
  • Mildura Birdlife, Wildside outdoors – canoeing, Mildura 4WD lnc. 
  • Mildura Rural City and Swan Hill Rural City councils 
  • Murray–Darling Basin Authority 
  • Parks Victoria 
  • Recreational groups (Sunraysia Apiarists Association, Riverside Golf Course, Sunraysia Bushwalkers 
  • Victorian Environmental Water Holder