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Covering 19,450 ha, it is bounded by the Murray River to the north and Gunbower Creek to the south. It is an internationally significant site under the Ramsar Convention and forms part of the Living Murray Gunbower- Koondrook-Perricoota forests icon site. River regulation and water extraction from the Murray River and Gunbower Creek has reduced the frequency, duration and magnitude of flood events in Gunbower Forest. This has affected the extent and condition of floodplain habitats and the health of plant and animal communities (such as river red gum and black box communities, native fish, birds, platypus, frogs and turtles) that depend on those habitats.

Gunbower Creek is a natural creek that has been modified to supply irrigation water from the Murray River to the Torrumbarry Irrigation Area. There are twelve lagoons, largely located in the upper reaches of the creek system, that are permanently or seasonally connected to Gunbower Creek. Water for the environment is used in Gunbower Creek to improve habitat for native fish, especially Murray cod.

The Living Murray environmental works program in the middle and lower forest was completed in 2013. The works allow up to 4,500 ha of the wetlands and floodplain to be watered with considerably less water than would be required if the watering infrastructure was not in place. The works enable efficient watering through Gunbower Creek and the forest to maintain wetland and floodplain condition and provide connectivity between the creek, forest floodplain and the Murray River. Frequent connections between the river and floodplain habitats allow biota to move between habitats and support critical ecosystem functions (such as carbon exchange).

Traditional Owners

System map

2018-Northern-Gunbower-map

Environmental watering objectives in Gunbower Creek and Forest

Provide feeding, breeding and refuge habitat for small-bodied native fish (such as Murray-Darling rainbow fish) in forest wetlands

Maintain and improve populations of large- bodied native fish (such as Murray cod) in Gunbower Creek
Provide suitable feeding, breeding and refuge habitat for frogs
Provide suitable feeding, breeding and refuge habitat for turtles
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Support carbon and nutrient cycles in the forest and wetlands and periodically deliver carbon and nutrients from the forest to adjacent waterways to support food webs
Maintain the health and increase the abundance of native vegetation in priority permanent and semi-permanent wetlands Improve the health of river red gums, black box and grey box communities
Provide feeding, breeding and refuge habitat for waterbirds including colonial nesting species (such as egrets, cormorants and herons)
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Maintain and improve water quality in Gunbower Creek

Environmental values

Gunbower Forest contains many important environmental values. It includes rare and diverse wetland habitats and large areas of remnant vegetation communities (such as river red gum forest and woodlands). It is also home to vulnerable and endangered plants and animals including river swamp wallaby grass, wavy marshwort, Murray-Darling rainbowfish, eastern great and intermediate egrets. It also supports internationally recognised migratory waterbird species.

Gunbower Creek provides important habitat for native fish (such as Murray cod, golden perch and freshwater catfish). It is a valuable refuge for native fish and provides a source of fish to recolonise surrounding waterways.

Traditional Owner cultural values and uses

The middle and lower area of Gunbower Forest is recognised as the traditional Country of the Barapa Barapa people, and the upper Gunbower Forest is recognised as the traditional Country of the Yorta Yorta people. North Central CMA seeks engagement and input from both Traditional Owner groups when undertaking annual water for the environment planning and throughout the year as part of the Living Murray Indigenous Partnerships Program.

Increasing the involvement of Traditional Owners in environmental water planning and management, and ultimately providing opportunities to progress towards self-determination within and beyond 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 (for example the Water Act 1989, the Victorian Aboriginal Affairs Framework, Water for Victoria (2016)) 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 1 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, and indicating progress towards this objective.

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

Barapa Barapa custodians have clearly expressed their aspirations for an active role in the management of land and water, to fulfil custodianship obligations and contribute to improvements in the health of Country.

Barapa Barapa Traditional Owners have been working in partnership with the North Central CMA to deliver the Water for Country project in Gunbower Forest since 2015. The Water for Country project builds on the work of the previous Barapa Barapa Cultural Heritage Mapping of Lower Gunbower Forest project, delivered in 2013-14 to map a catalogue of cultural heritage assets in the forest. The Water for Country project aims to investigate how Traditional Owners’ cultural and spiritual values may be better represented in water management. In 2018, the Water for Country group has evolved to also include Wemba Wamba Traditional Owners and continues to have a focus on Gunbower Forest.

Barapa Barapa Wemba Wamba Water For Country project members identified a range of opportunities for 2021-22 watering to support cultural values (Table 1).

Social, recreational and economic values and uses

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

  • water-based recreation (such as boating, canoeing, duck hunting, fishing, and stand-up paddle boarding and water skiing)
  • riverside recreation and amenity (such as birdwatching, camping, photography and walking)
  • community events and tourism (such as park visitation, tour and activity operators)
  • socio-economic benefits (such as consumptive water users including irrigation and domestic use, timber harvesting and education).

Recent conditions

Rainfall and temperatures in the Gunbower Forest and surrounding areas were close to the long-term average during 2020-21. Carryover of water in the Murray system was important to meet demands for water for the environment early in the water year. Allocations against high-reliability water shares in Victorian Murray entitlements to water for the environment, which are used to supply Gunbower Forest and Gunbower Creek, reached 55 percent in October 2020 and 100 percent in February 2021. Water for the environment was delivered to Gunbower Forest and Gunbower Creek in line with an average climate scenario in 2020- 21, and most planned actions were achieved.

Small peaks in the Murray River delivered minor inflows to Gunbower Forest via low-lying flood runners in July 2020. Another short peak in September 2020 was excluded from the forest by closing the regulators on the Murray River to prevent nuisance flooding of Yarran Creek. In late winter/spring 2020, water for the environment was used to fill Reedy Lagoon and Black Swamp within Gunbower Forest. Some of the water from Black Swamp spilled into wetlands within the Little Gunbower wetland complex. Other wetlands within Gunbower Forest were allowed to draw down during the first half of 2020-21, to reduce carp.

Additional deliveries of water for the environment in autumn 2021 topped up Reedy Lagoon and filled the Little Reedy wetland complex. The planned autumn top-up watering action at Black Swamp did not proceed, to allow the wetland to dry and hence reduce carp abundance ahead of a planned fill in winter/spring of 2021-22.

Fishway construction activities in Gunbower Creek limited deliveries of water for the environment to Gunbower Forest via the Hipwell Road Regulator in autumn and early winter 2021. Vegetation monitoring in autumn 2020 detected a slight decline in the condition of river red gums in some parts of the forest. Delivering water to selected wetlands and river red gum stands is proposed after the construction works conclude in winter/spring 2021, and more extensive floodplain watering in autumn/winter/ spring 2022 is a high priority to improve tree and understorey condition and provide habitat for native fish and waterbirds.

In Gunbower Creek, water for the environment was used to maintain access to habitat and food resources for native fish during winter 2020 (when irrigation flows cease) and to promote spawning and improve the quality of nursery habitats for native fish (especially Murray cod) during spring and summer. Construction of new fishways at Cohuna Weir and Koondrook Weir commenced in May 2021 and should be completed by August 2021. During the construction period, there will be little flow in Gunbower Creek, and pool habitats will be maintained downstream of the weirs to support native fish.

Annual fish surveys in Gunbower Creek have detected successful breeding and survival of Murray cod each year that water for the environment has been delivered, and the surveys are showing improvements in abundance and age structure within the resident Murray cod population over time. Freshwater catfish are also breeding in Gunbower Creek. Environmental flows will be necessary to help restore native fish habitat and support fish dispersal from the managed refuge pools once the fishway construction activities are complete. The fishways are expected to significantly improve the abundance and diversity of fish populations over time by allowing fish to move between Gunbower Creek and the Murray River. This will enable fish that successfully breed in Gunbower Creek to migrate into the Murray system and for species (such as golden perch and trout cod) that breed elsewhere to move into Gunbower Creek to feed and develop. Greater fish movement into and out of Gunbower Creek will help to grow populations of native fish within Gunbower Creek and across the broader region.

Scope of environmental watering

Table 1 Potential environmental watering actions, expected watering effects and associated environmental objectives for Gunbower Creek and Forest

Potential environmental watering action

Expected watering effects

Environmental objectives

Gunbower Forest

Little Reedy wetland complex and Reedy Lagoon top-up (winter/ spring 2021)

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  • Maintain water depth and extent to support the growth and successful recruitment of wetland vegetation
  • Maintain water depth and quality to provide habitat for small-bodied native fish
  • Provide a diversity of water depths throughout the season to provide feeding and breeding habitat for water-dependent biota including waterbirds, turtles and frogs
Fish iconFrog iconTurtle iconPlant iconHeron icon

Black Swamp and Little Gunbower wetland complex fill (winter/spring 2021)

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Black Swamp, Little Gunbower wetland complex, Little Reedy wetland complex and Reedy Lagoon overtop (winter/spring/summer 2021)

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  • Increase water depth and extent to support the growth and successful recruitment of wetland and surrounding river red gum understorey flood-dependent vegetation
  • Increase water depth and quality to provide habitat for small-bodied native fish
  • Maintain a diversity of water depths throughout the season to provide feeding and breeding habitat for water-dependent biota including waterbirds, turtles and frogs

Fish iconFrog iconTurtle iconPlant iconHeron icon

Winter/spring fresh in Yarran Creek (variable flow rates and duration based on water levels in Gunbower Forest and flows in the Murray River and Gunbower Creek)

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  • Provide connectivity between Gunbower Creek and Murray River through the Yarran Creek and Shillinglaws regulators, to increase flowing habitat for the lateral movement of native fish, turtles, carbon and nutrients
  • Provide migration and spawning opportunities for native fish

Fish iconTurtle iconConnected icon

Extend natural flooding in Gunbower Forest floodplain, floodrunners and wetlands (with variable flow rates to maintain an appropriate wetted extent during winter/spring 2021)

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  • Extend the duration of floodplain and wetland inundation over the optimal growth season
  • Maintain water depth and quality to provide habitat for small-bodied native fish including Murray-Darling rainbowfish
  • Maintain a diversity of water depths throughout the season to provide feeding and breeding habitat for water-dependent biota including waterbirds, turtles and frogs

Fish iconFrog iconTurtle iconPlant iconHeron icon

Trigger-based top-up of permanent and semi- permanent wetlands (variable flow rates during spring/summer as required in response to bird breeding event)

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  • Maintain a waterbird breeding event
  • Maintain the wetland vegetation to provide habitat for colonial nesting and flow-dependent waterbirds

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Reedy Lagoon autumn/ winter top-up (2022)

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  • Maintain water depth and extent to support the growth and successful recruitment of wetland vegetation
  • Maintain water depth and quality to provide habitat for small-bodied native fish including Murray-Darling rainbowfish
  • Maintain a diversity of water depths throughout the season to provide feeding and refuge habitat for water-dependent biota including waterbirds, turtles and frogs

Fish iconFrog iconTurtle iconPlant iconHeron icon

Gunbower Forest floodplain, floodrunners and wetlands inundation (with variable flow rates during autumn/winter 2022)

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  • Inundate river red gums and the flood-dependent and flood-tolerant understorey species
  • Provide access to breeding habitat and food resources for native fish (such as Murray cod)
  • Provide habitat for frogs, turtles, small-bodied native fish and waterbirds including colonial nesting species

Fish iconFrog iconTurtle iconPlant iconHeron icon

Gunbower Creek

Irrigation season low flow (300-500 ML/day during August to March)

  • Maintain habitat and food resources for native fish (such as Murray cod) by minimising large variations in the water level during the irrigation season
  • Provide cues for the migration and spawning of native fish
  • Maintain connectivity between Gunbower Creek, lagoons and fishways, to maintain habitat for the movement of native fish
  • Dilute low-oxygen water exiting Gunbower Forest below Koondrook Weir if required

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Autumn/winter low flow (above 200 ML/day during March to June 2022)1

  • Maintain habitat and food resources for native fish (such as Murray cod) during the off-irrigation period and/or when Hipwell Road regulator is operational
  • Maintain connectivity between Gunbower Creek, lagoons and fishways, to maintain habitat and support the movement of native fish

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Autumn/winter freshes (500 ML/ day for one to four weeks during July to August 2021 and May to June 2022)

  • Make delivery in response to high flow in the Murray River and low- oxygen water draining off Gunbower Forest during the non-irrigation season to protect water quality and allow fish to move between the Murray River and Gunbower Creek

Fish iconWater drop icon

1 This flow is prioritised only when deliveries are occurring to Gunbower Forest through Hipwell Road regulator.

Engagement

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

Table 2 Partners and stakeholders engaged in developing the Gunbower Creek and Forest seasonal watering proposal

Partner and stakeholder engagement
  • Gunbower Island Community Reference Group
  • Commonwealth Environmental Water Office
  • Department of Environment, Land, Water and Planning
  • Goulburn- Murray Water
  • Murray- Darling Basin
  • Authority (the Living Murray program and River Operations)
  • Forestry Corporation of NSW
  • Parks Victoria
  • Vic Forests
  • Gannawarra Shire Council
  • Campaspe Shire Council
  • Individual landholders
  • Forestry
  • Field and Game Australia
  • Gateway to Gannawarra Visitor centre
  • Vegetation, fish and bird ecologists
  • Yorta Yorta Nation Aboriginal Corporation
  • Barapa Barapa Traditional Owners

Page last updated: 22/06/21