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Package of works
The future of native fish in the Gunbower and lower Loddon systems has never been better with the injection of $7.1 million funding from the Victorian Government's 2020 Building Works capital (COVID -19) stimulus package.
The North Central CMA has received the funding to undertake improvements to fish passage within the systems. These improvements, through the Native Fish Stimulus project, will largely see the upgrade or construction of fishways and fish screens allowing the movement and protection of native fish within the systems.
The package of works area a key part of the North Central CMA’s Native Fish Recovery Plan to recover native fish populations and establish a world-class fishery in northern Victoria. The completed works will also contribute to the region’s recreational and social values as recreational fishing contributes $304 million annually to the regional economy in north western Victoria.
It is estimated that native fish populations have decreased by 90% across the Murray Darling Basin since early European settlement. Many factors have contributed to this decline including lack of connectivity; removal of habitat; altered flows and entrainment into irrigation channels and pumps:
Works are already underway at various sites across the Gunbower and lower Loddon. The works will be timed so there is no impact to the delivery of water for irrigators. The fishways will operate using the existing water allocations, making every drop count twice.
North Central CMA will manage the environmental and cultural heritage approvals for the proposed works. GMW will be responsible for the detailed design and construction of the fishways and fish screen with technical support from the North Central CMA.
To read more, including location of project sites and detail regarding what's planned and progress at each site, click links to the left.
The Native Fish Recovery Plan project area covers the Gunbower and lower Loddon basins in the North Central CMA region.
The area comprises public and private land that includes Gunbower Forest (a large Ramsar wetland) and most of the Torrumbarry Irrigation Area, a large irrigation area that grows more than $130 million of agricultural produce a year. The area is supplied by 280 km of streams that are largely managed for water delivery through a system of weirs and channels.
The map indicates the proposed fishway and irrigation screen sites through the Native Fish Stimulus package of works.
Koondrook Weir is at the lower end of Gunbower Creek, about six kilometres upstream from the creek’s confluence with the Murray River. The weir maintains a stable pool level to provide water to the No. 4 and No. 5 channels during the irrigation season but was one of the barriers along Gunbower Creek for upstream fish passage.
Previous works upstream have seen vertical slot fishways built at Gunbower Weir and Hipwell Road Weir, and a rock ramp fishway at Thompsons Weir. Gunbower Creek is an important economic and environmental asset to the region, providing a range of values to Gunbower, Cohuna, Leitchville and Koondrook communities.
The creek is part of the Torrumbarry Irrigation Area and is primarily operated as an irrigation channel to deliver water for domestic and agricultural use. Water from the Murray River is diverted into Gunbower Creek via the National Channel above Torrumbarry Weir and is controlled by a series of weirs and regulators. Gunbower, Thompsons, Cohuna and Koondrook weir pools control water that is extracted by direct diverters as well as delivered throughout the irrigation district via the No.3, No.4 and No.5 channels.
Gunbower Creek runs parallel to the Murray River creating a forested island floodplain of up to eight kilometres wide. The floodplain is a Living Murray Icon Site, of which Gunbower Creek forms the southern boundary.
The Koondrook Fishway is part of our flagship Native Fish Recovery Plan, and one of 11 locations in the Gunbower and lower Loddon catchment where we are working on connectivity, allowing native fish to move freely through the previously fragmented irrigation system. The bold vision in our plan that fish passage infrastructure will be installed or improved at each one of these locations to reconnect this system to over 530 km of open Murray River. To date, eight fishways have been installed including the fishway here at Koondrook. The CMA has two-funded fishway projects on Taylors Creek planned for 2022, leaving the National Channel as the last barrier in the system.
Launched in December 2021, the fishway was funded with a combination of $4.6M from the Victorian Environmental Water Holder (VEWH) and $1.45M from Victorian Government – Building Works capital stimulus package 2020 – Waterway Environmental Works component. Bendigo-based company S&R Engineering undertook constructions works overseen by Goulburn-Murray Water.
Recent monitoring
Fish ecologists from Arthur Rylah institute undertook monitoring of the fishway in December 2021. The monitoring captures fish in a cage at the fishway opening before being released into the creek and confirmed small to medium bodied fish are, for the first time in decades, moving freely from the Murray River into Gunbower Creek. Juvenile silver perch made up a large portion of the fish trapped which is promising news for an increase of native fish populations in the creek.
Silver perch are Critically Endangered (EPBC Act) fish is one of the target species for the Native Fish Recovery Plan.
The No. 4 and 5 Channels are located immediately upstream of Koondrook Weir.
With the construction of a new Koondrook Fishway at Koondrook complete it is estimated that ~20% migrating golden perch will be entrained into these channels if they are not screened.
A concept has been developed for a self-cleaning fish screen (four conical screens) in front of the channels at this site with the constructions of the fishscreens complementing the new fishway
Gunbower Weir Fishway was constructed in 2008 and does not meet current guidelines for small-bodied fish passage.
The concept design includes installing key-hole slots in the existing structure to address small-bodied fish movement.
Upgrade to the fishway will allow movement of small and medium fish including the Threatened Murray-Darling rainbowfish, and juvenile golden perch, silver perch and Murray cod.
Initial works to prepare the fishway will commence in June with completion scheduled for June 2023.
Goulburn-Murray Water funded the construction of a 23-slot vertical slot fishway at Cohuna Weir during 2021.
Re-built in 2005, the Cohuna Weir on Gunbower Creek was one of the last barriers to upstream fish passage along Gunbower Creek.
The completed fishway allows safe passage for iconic fish species including the golden perch, threatened silver perch and Murray cod upstream and downstream of the existing weirs and importantly access to critical breeding habitat throughout the entire Gunbower Creek.
The fishway was one of the last few remaining locations in the Gunbower and lower Loddon catchment where we are working on connectivity, allowing native fish to move freely through the previously fragmented irrigation system through the North Central CMA’s Native Fish Recovery Plan..
The provision of fish passage along the entire length of Gunbower creek then enables connection to more than 530 km of open Murray River. This is a high ecological priority for the Native Fish Recovery Plan – Gunbower and Lower Loddon, the Living Murray Program and North Central Regional Catchment Strategy.
Dehnes Weir is located at the outlet of Taylors Creek into Ghow (Kow) Swamp.
In partnership with GMW, the developed detailed design of a dual chamber, vertical slot fishway meets the ecological goals of the Native Fish Recovery Plan while responding to a number of site specific constraints. The “no dig” design responds to the cultural and archaeological significance of Ghow (Kow) Swamp and feedback from consultation with Yorta Yorta Nation. The dual chamber design also provides a wide operating range that will provide fish passage now and responds to irrigation delivery scenarios in a drying climate. North Central CMA is committed ongoing Traditional Owner engagement, listening and design adaptation to achieve native fish outcomes and respecting cultural heritage.
The North Central CMA is working with partners to secure additional funding to proceed with construction in winter 2023. Once constructed, together with the completed fishway at Talyors Weir, it will connect native fish in Ghow (Kow) Swamp to the Murry River via the Gunbower and lower Loddon in an unbroken loop of more than 150 km.
Taylors Weir is approximately 2 km upstream of the outlet of Taylors Creek to Ghow (Kow) Swamp.
A detailed design for the fishway is complete and construction will start in May though to December 2022. Construction works will not impact the irrigation delivery season starting on 15 August.
From the 15 May to mid-June, water levels from the National Channel offtake through Taylors and Gunbower Creeks will drawdown to build cofferdams for safe and dry access to the regulator. When the cofferdams are built flows will resume to provide water for irrigation storage and the environment.
The CMA has worked closely with the community and other stakeholders to ensure water for the environment is maintained in Taylors Creek, Gunbower Creek and Pyramid Creek for the majority of the irrigation off season.
GMW are responsible for construction of the fishway and we're working closely with them to ensure the environmental and cultural heritage aspects of the construction phase are managed appropriately. In addition, the North Central CMA will lead the ecological monitoring process.
The completed fishway will be one of the last remaining barriers removed for fish movement within the lower Loddon and Gunbower systems.