VEWH - Barmah Forest

The Barmah-Millewa Forest covers 66,000 ha and straddles the Murray and Edwards rivers between the townships of Tocumwal, Deniliquin and Echuca. The Victorian component is the Barmah National Park and River Murray Reserve covering 28,500 ha of forest and wetlands.

Water management in the Barmah-Millewa Forest depends on gravity distribution from the River Murray. When river flows are above 15,000 ML/day downstream of Yarrawonga Weir, both sides of the forest are managed as a whole. When flow is less than 15,000 ML/day, each side of the forest can be managed separately by operating the regulators individually. When flow downstream of Yarrawonga Weir is less than 10,500 ML/day, all regulators are usually closed to prevent unseasonal flooding of the forest in summer and autumn.

River regulation and water extraction from the River Murray has reduced the frequency, duration and magnitude of flood events in the Barmah-Millewa Forest. This has reduced the diversity, extent and condition of vegetation communities and the habitat and health of dependent animal species.

Environmental water releases aim to protect essential habitat under dry conditions and when possible to build on unregulated flows and consumptive water en route to optimise environmental outcomes. Environmental water delivered to the forest can often be used again at sites further downstream as part of multisite watering events.

System map

Environmental watering objectives in Barmah Forest

Enhance the health of river red gum communities and aquatic vegetation in the wetlands and watercourses and on the floodplain Promote the growth of floodplain marsh vegetation communities, particularly the extent of Moira grass growing in these areas

Maintain or increase available habitat for frogs

Provide feeding and nesting habitat for the successful recruitment of colonial nesting waterbirds

Maintain or increase the habitat available for turtles including the broad-shelled turtle 

Provide native fish with access to a range of floodplain, riverine and refuge habitats including by delivering variable flows that promote spawning  

Enable nutrient cycling (particularly carbon) between the floodplain and river through connectivity Provide early-season flushing of the lower floodplain to cycle nutrients during cooler conditions and reduce the risk of poor waterquality events in summer

Environmental values

The Barmah–Millewa Forest is the largest river red gum forest in Australia and the most-intact freshwater floodplain system along the River Murray. The forest supports important floodplain vegetation communities including the threatened Moira grass plains and is a significant feeding and breeding site for waterbirds including bitterns, ibis, egrets, spoonbills and night herons. Significant populations of native fish, frogs and turtles also live in the forest's waterways. Barmah Forest is known to support 74 plant and animal species protected under state and national legislation.

Social and economic values

The Barmah Forest supports a variety of recreational and tourism activities (such as bushwalking, boating, fishing, river cruises and birdwatching). Camping is popular along much of the 112 km frontage to the River Murray, a destination people choose for its majestic river red gums, sandy beaches and varied wildlife. Four canoe trails have been developed in the park and the forest also provides excellent fishing opportunities, particularly for Murray cod, golden perch, freshwater catfish and yabbies.

Barmah Forest is also valued for its European heritage values, largely associated with past forestry and grazing practices.

Conditions 2018

Barmah Forest was inundated in 2017–18 through managed and natural flooding. In 2017–18, a new approach to regulator operation was trialled at Barmah– Millewa Forest. Most forest regulators remained open between July and November 2017, as low flows (below choke capacity) were passed through to allow a morenatural rise and fall in the forest's waterways. This improved habitat in the forest's waterways by providing variable flows, and the same approach is planned for 2018–19.

A natural flood in August 2017 (35,000 ML per day) inundated 40 to 45 percent of the active floodplain; another in early December 2017 (20,000 ML per day) reached 17 to 20 percent of the floodplain. Flow levels between
these two peaks were sustained by delivering water for the environment (15,000 ML per day through October and November 2017) to meet the water needs of the floodplain's marshlands.

Excellent vegetation and fish outcomes were recorded in 2017–18, including strong Moira grass growth and flowering as well as native fish breeding. Water for the environment was delivered to colonial waterbird breeding sites in Barmah Forest, with delivery ending early at one site due to the abandonment of nests after predation by feral pigs.

Scope of environmental watering

Table 1 Potential environmental watering actions and objectives for Barmah Forest

Potential environmental watering	Environmental objectives
Winter/spring low flows to various waterways in Barmah Forest (variable flow rates in July– December)	Maintain fish and turtle habitat in forest waterways Facilitate the movement of native fish between floodplain waterways and the river Remove accumulated organic matter: cycle carbon to the river system and minimise the risk of anoxic blackwater
Spring/summer freshes (in-channel) in the River Murray channel (up to 3 events of 500 ML/day for 8 days in October–December)	Trigger spawning of native fish species, primarily golden and silver perch
Spring/summer freshes (drought) to Gulf and Boals creeks (100 ML/day for 3–5 days as required in November–April)	Maintain critical drought-refuge areas in Barmah Forest Protect fish and turtle populations in permanent waterways Maintain water quality
Spring/summer/autumn low flows to floodplain waterways including Sandspit, Gulf, Big Woodcutter, Boals, Island and Punt Paddock Lagoon (200 ML/day for 30–60 days between November–April) ¹	Replenish refuge areas and maintain water quality in those areas Maintain fish and turtle populations in permanent waterways Maintain connectivity to the river Remove accumulated organic matter: cycle carbon to the river system and minimise the risk of anoxic blackwater
Spring inundation of floodplain marshes (variable flow rates for 3 months in September– December)²	Provide flooding of sufficient duration to allow growth of floodplain marsh vegetation in open plains Create foraging ground for birds and increase available habitat for turtles, frogs and small-bodied native fish
Targeted wetland watering to Boals Deadwood, Reedy Lagoon and Top Island wetlands (100–250 ML/day for 4 months in September–February)	Initiate and/or maintain the breeding of colonial nesting and flowdependent waterbirds
Targeted wetland watering to Boals Deadwood, Reedy Lagoon and Top Island wetlands (200– 400 ML/day for 4.5 months in September– February)	Initiate and/or maintain breeding habitat for colonial nesting and flowdependent waterbirds
Autumn/winter low flows (up to 5,000 ML/day downstream of Yarrawonga in May to August)	Increase habitat for large-bodied native fish in the River Murray and anabranches in Barmah–Millewa Forest

¹May be delivered across multiple events.

² Water for the environment is limited to flow rates outlined in the MDBA's Objectives and Outcomes for River Operations in the River Murray System (MDBA, 2016).

Risk management

In preparing its seasonal watering proposal, the Goulburn Broken 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 organisations with which Goulburn Broken CMA engaged when preparing the Barmah Forest 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 Goulburn Broken Regional Catchment Strategy and the Goulburn Broken Waterway Strategy.

Table 2 Partners engaged in developing the Barmah Forest seasonal watering proposal

Partner and stakeholder engagement
Commonwealth Environmental Water Office Department of Environment, Land, Water and Planning Murray–Darling Basin Murray–Darling Basin Authority (River Murray Operations and Living Murray program) NSW National Parks and Wildlife Service NSW Office of Environment and Heritage Parks Victoria Victorian Environmental Water Holder Yorta Yorta Nation Aboriginal Corporation