VEWH - Gunbower Creek and Forest

Gunbower Forest, which covers 19,450 ha, 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 have 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 12 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 the 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 animals to move between habitats and support critical ecosystem functions (such as carbon exchange).

System 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 
 Improve populations of large-bodied native fish (such as Murray cod) in Gunbower Creek

Increase the diversity and abundance of native frog species within the forest

Maintain the population of freshwater turtles by providing suitable feeding, breeding and refuge habitat

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

Improve the health and increase the abundance of native vegetation in permanent and semi-permanent wetlands  Improve the health of river red gums and black box communities

Provide feeding, breeding and refuge habitat for waterbirds, including colonial nesting species (such as egrets,  cormorants and herons)

Maintain 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 home to vulnerable and endangered plants and animals, including river swamp wallaby grass, wavy marshwort, Murray-Darling rainbowfish, and eastern great and intermediate egrets. Gunbower Forest also supports internationally recognized migratory waterbird species.

Gunbower Creek provides important habitat for native fish, such as Murray cod, golden perch, and freshwater catfish. It serves as a valuable refuge for native fish and acts as a source for fish to recolonize surrounding waterways.

Traditional Owner cultural values and uses

The Barapa Barapa are the Traditional Owners in the middle and lower area of Gunbower Forest, and the Yorta Yorta are the Traditional Owners in the upper Gunbower Forest.

The North Central CMA seeks engagement and input from both Traditional Owner groups when undertaking annual environmental water planning and throughout the year as part of the Living Murray Indigenous Partnerships Program.

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

Barapa Barapa custodians and North Central CMA staff spent two days in Gunbower Forest in early 2023 to reflect on the condition of the forest and creek, share knowledge, and discuss environmental watering plans for 2023-24 and other opportunities to improve the health of the forest and creek. Barapa Barapa custodians released several Murray cod and golden perch that were salvaged during the low-oxygen blackwater event in 2022 back into Gunbower Creek. Concerns were raised about the potential for future low-oxygen blackwater events.

Increasing the involvement of Traditional Owners in environmental water management and progressing opportunities towards self-determination in 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, including the Water Act 1989, the Victorian Aboriginal Affairs Framework, the 2016 Water for Victoria, the Water is Life: Traditional Owner Access to Water Roadmap 2022, 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 5.2.7 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.

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

Barapa Barapa custodians 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 can be better represented in water management. In 2018, the Water for Country group expanded to also include Wamba Wemba custodians; the group continues to focus on Gunbower Forest.

Table 5.2.5 identifies opportunities to support cultural values with water for the environment. These have been informed by the Barapa Barapa Watering Objectives Framework (see Table 5.2.6) and North Central CMA engagement with Barapa Barapa custodians in early 2023.

Table 5.2.5 Cultural values and uses at Gunbower Forest as identified by the Barapa Barapa Wamba Wemba Water for Country project

Value/use	How the value/use will be considered by environmental flows in 2023-24
Cultural plants, cultural practices	Water in wetlands and on the floodplain from deliveries of water for the environment and natural flooding supports culturally important plants throughout Gunbower Forest and allows the continuation of cultural practices, including harvesting of food, medicine, and weaving plants. The watering actions via the Hipwell channel in 2023-24 will support cultural plants that Barapa Barapa custodians value and provide opportunities for cultural practices to continue. The abundance of cultural resources available is linked to the scale of watering that can be achieved. Floodplain watering via the Hipwell channel provides a greater amount of resources and enables resourceful harvests with less travel and effort. Barapa Barapa custodians recognise the value of resources that occur on the drawdown after the inundation of the forest floodplain, providing food for animals and cultural plants (such as old man weed). This can be supported by allowing wetlands to draw down naturally prior to the floodplain watering in winter 2023 and through summer and autumn 2024. Having a diversity of habitat and vegetation responses is a priority for Barapa Barapa custodians. They consider it important to have a range of water depths, which creates a more diverse vegetation response and results in a variety of resources becoming available over a longer period.
Healthy Country	Providing drought refugia and maintaining areas with healthy habitat is a high priority for Barapa Barapa custodians. Deliveries of water for the environment will ensure water is present on the floodplain and in high-priority wetlands regardless of whether there is unregulated flooding. This will provide refuge habitat for forest fauna, and the delivery of water across most of the Gunbower Forest wetlands will ensure that high-quality habitat is available.
Cultural heritage	Barapa Barapa custodians value having water in natural creeks and billabongs off main wetlands, which can contain cultural heritage sites, including earth mounds and a large canoe tree on the edge of a large flood runner. Delivering water to the floodplain supports this with water flowing through natural creeks and flood runners on the floodplain. Deliveries of water for the environment result in lower levels than natural flooding, which can ensure that earth mounds or other cultural heritage are not overtopped and harmed. Barapa Barapa custodians have noted that areas of black box and river red gum have cultural heritage values, but the changed watering regime since regulation and climate change is causing the encroachment of black box into areas previously dominated by river red gum. Barapa Barapa custodians expressed the desire to preserve the tree community that was historically present, which is supported by the delivery of water to the floodplain. The lower landscape regulators can target small areas of river red gum, and the Hipwell channel watering planned in 2023-24 will inundate large areas of river red gum and potentially suppress black box encroachment within the flood footprint.
Cultural practices	Barapa Barapa custodians have aspirations to reintroduce traditional fish traps into natural creeks within Gunbower Forest. The flood runners around the Little Gunbower Creek complex have been identified as potential trial sites, and opportunities may be provided to pursue this in 2023-24. Traditional Owners have indicated that a smoking ceremony should be a regular activity each year when water is delivered, as it is something that their ancestors would have done when the floodwaters arrived and would represent a restoration of an important cultural practice. The timing of deliveries of water for the environment will be communicated to Traditional Owners so cultural opportunities can be realized.
Cultural resources	Barapa Barapa custodians have expressed that the ongoing survival of fish populations is important, as the fish are a food resource. In 2023, Barapa Barapa custodians are placing a high priority on protecting native fish populations in Gunbower Creek and avoiding any further fish deaths due to low-oxygen blackwater. Native wetland fish populations persisting in the Gunbower Forest wetlands following the 2022 floods will be supported by the planned floodplain watering, ensuring a resident fish population persists across multiple years. Watering the wetlands will also provide habitat for freshwater mussels in the wetlands.

The Barapa Barapa Wamba Wemba Water for Country project has led to the creation of the Barapa Barapa Cultural Watering Objectives Framework, which is a guiding document to ensure cultural priorities and outcomes are considered and incorporated in the planning for and management of water for the environment. The framework considers cultural objectives matched with hydrological considerations, indicators and measures for monitoring success, which Table 5.2.6 shows. These objectives are considered in conjunction with the environmental objectives and expected effects of the potential watering actions shown in Table 5.2.7.

Applying the framework during seasonal watering proposal engagement with the Barapa Barapa Wamba Wemba Water for Country project members ensures that planned environmental flows incorporate Barapa Barapa custodians’ cultural aspirations and that water managers are culturally informed when delivering water for the environment.

All the potential environmental watering actions in Table 5.2.7 provide the opportunity to support Barapa Barapa cultural values and objectives. Achieving them will depend on climatic conditions.

Table 5.2.6 Barapa Barapa cultural objectives for environmental flows in Gunbower Forest 2023-24 (from the Barapa Barapa Cultural Watering Objectives Framework)

Cultural objective	Hydrological aim	Indicator	Measure	Watering action
Promote and maintain healthy and abundant native fish communities in Gunbower Creek and Gunbower Forest	Presence of water in wetlands before spring to support native fish spawning events	Presence of native fish spawning Native fish populations show a range of ages	Fish surveys, larval sampling	Floodplain watering Wetland top-ups Yarran throughflow
	Presence of water in deep wetlands so that fish can survive for longer	Presence of native fish following watering event	Fish surveys
	Hydrological aim 3	Presence of native fish following watering event	Fish surveys
Promote the natural flow of water	Water flows via natural flow paths to culturally important sites	Presence of water at culturally significant sites (e.g., fishponds)	Photo points, site surveys
Promote the natural flow of water	Presence of healthy-looking and healthy-smelling forest	Presence of healthy canopies and good ground cover on the forest floodplain	Plant surveys
Promote and maintain healthy cultural plants and resources	Presence of water on the floodplain, in small wetlands, and in depressions to provide resources across the forest, particularly in dry years	Presence of food and fibre resources distributed across the forest	Cultural harvests, plant surveys, seed collection
Promote and maintain healthy cultural plants and resources	Presence of water in healthy wetlands	A diverse range of plants, animals, and insects living in harmony	Results of monitoring activities (e.g., macroinvertebrate surveys, flora and fauna surveys)
Promote healthy waterbird populations	Presence of water in wetlands that support waterbird breeding	Presence of waterbird breeding	Waterbird surveys, spring/summer surveys for eggs

Social, recreational and economic values and uses

In planning the potential environmental watering actions in Table 5.2.7, the North Central CMA considered how environmental flows could support values and uses, including:

Water-based recreation (such as boating, canoeing, duck hunting, fishing, 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)
Socioeconomic benefits (such as consumptive water users, including irrigation and domestic use, timber harvesting and education)

Where possible, releases will be timed to minimise disruption to community uses.

Scope of environmental watering

The term ‘environmental watering’ refers to the active delivery of held environmental water to support particular environmental objectives by altering the flow in a river or the water level in a wetland. While other terms are sometimes used to describe the delivery of environmental water, ‘environmental watering’ is deliberately used here and in seasonal watering statements to ensure consistency in the legal instruments that authorise the use of water for the environment in Victoria.

Table 5.2.7 describes the potential environmental watering actions in 2023-24, their expected watering effect (that is, the intended physical or biological effects of the watering action) and the longer-term environmental objectives they support. Each environmental objective relies on one or more potential environmental watering actions and their associated physical or biological effects.

Table 5.2.7 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

Gunbower Forest floodplain, floodrunners and wetlands inundation (with variable flow rates during winter/ spring 2023)

Part B: JulyNovember 2023¹

Continue floodplain watering commenced in June 2023 to inundate for a second consecutive year river red gums, which are still recovering from the Millennium Drought
Inundate flood-dependent understorey vegetation across the floodplain to support further its establishment and recolonisation to supplement recruitment during the 2022-23 floods
Provide a variety of water depths throughout the forest to provide feeding, foraging and refuge habitat for frogs, turtles and waterbirds, including juveniles from colonial nesting species, and access to breeding habitat for small-bodied native fish

Extend natural flooding in Gunbower Forest floodplain, flood runners and wetlands (with variable flow rates to maintain an appropriate wetted extent during winter/spring 2023)

Where possible, extend the duration and/or extent of natural floodplain and wetland inundation over the optimal growing season for aquatic vegetation; the objectives are as per the previous action, with a greater area of floodplain inundated

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)

Connect Gunbower Creek, Gunbower Forest, and the Murray River through the Yarran Creek and/or Shillinglaws regulators to increase flowing habitat for the lateral movement of native fish, turtles, carbon, and nutrients

Black Swamp, Reedy Lagoon, Little Gunbower Creek complex, Little Reedy wetland complex (top-up, variable flow rates during spring/ summer as required in response to bird breeding)

Maintain adequate water levels in breeding and feeding habitats to allow breeding waterbirds to successfully fledge their chicks

Black Swamp, Reedy Lagoon, Little Gunbower Creek complex, Little Reedy wetland complex (top-up, variable flow rates during autumn/ winter 2024 as required)

Maintain a variety of water depths across the floodplain wetlands to provide feeding, foraging, and refuge habitat for frogs, fish, turtles, and waterbirds, including juvenile colonial nesting species

Gunbower Creek (targeting Cohuna Weir)

Spring/summer/autumn flow (300-400 ML/day during September to March)

Maintain habitat and food resources for native fish and support breeding and larval survival (such as Murray cod) by minimising large variations in the water level during the irrigation season and achieving about 1.5 m depth in deeper pools and 30 cm depth in the shallow connecting littoral zone to maintain habitat
A greater area of habitat will be inundated at the upper magnitude

Summer/autumn/winter opportunistic fresh(es) (200-500 ML/day for one to four weeks during July to August 2023 or January to June 2024)

Increase flowing habitat in Gunbower Creek to provide preferred hydraulic conditions for native fish
Lower the Koondrook Weir pool during this event to create a hydraulic head difference and increase the amount of flowing habitat for native fish in Gunbower Creek

Autumn/winter low flow (200 ML/day during July to August and March to June)

Maintain connectivity through the length of Gunbower Creek and between lagoons and fishways during the off-irrigation period and prevent sections from drawing down to isolated pools
Provide access to food resources over the cooler months and reduce predation pressure on juvenile fish

Gunbower Creek (targeting Koondrook Weir)

Year-round opportunistic fresh(es) (300-500 ML/day for one to four weeks, as required)

Deliver in response to high flow in the Murray River (if conditions allow) to:

Promote the exchange of carbon between Gunbower Creek and the Murray River
Provide a natural cue to attract native fish (such as Murray cod if delivered in spring and golden perch and silver perch if delivered in autumn) to migrate into or to the upstream reaches of Gunbower Creek, maximizing the effects of the fishways at Koondrook and Cohuna weirs

Trigger-based spring/ summer low flow (50- 300 ML/day as required during September to February)

Dilute carbon-rich water exiting Gunbower Forest at Three Corner Hole to improve water quality (oxygen concentrations) in lower Gunbower Creek if required

¹This potential watering action is Part B of a watering action that commenced in 2022-23.

Page last updated: 01/12/22