About Lower Murray: Locks 8 and 9 project
Part of the NSW Government’s Sustainable Diversion Limit Adjustment Mechanism (SDLAM) Acceleration Program, the Lower Murray: Locks 8 and 9 Project aims to enhance connectivity across the Frenchmans Creek and Carrs, Capitts and Bunberoo creek waterways by implementing weir pool operational changes and modifying associated water management infrastructure.
The project is a collaborative initiative designed to address environmental issues within the lower Murray, surrounding wetlands and connected creek systems.
The NSW Government is working with SA Water to deliver the project.
About Locks 8 and 9
Locks 8 and 9 are 2 of the 14 weirs and locks constructed on the lower Murray between 1922 and 1939. They are located downstream of the Murray-Darling junction in southwestern NSW, between Wentworth and the South Australian border.
The weirs regulate river flow by each creating a stable pool of water held at a level several metres above the original river height. The associated locks allow boats to pass from one weir pool to the next. The weir pool at Lock 9 also enables the transfer of water into Lake Victoria via Frenchmans Creek, an anabranch of the Murray River upstream of Lock 9.
While the locks and weirs have provided significant economic benefits, they’ve also had environmental impacts. In particular, they have impacted the Carrs, Capitts and Bunberoo creek systems, an interconnected group of floodplain waterways isolated from the main Murray channel by fixed crest weirs on the Lock 9 weir pool.
The weirs have reduced the ability of native fish to migrate for breeding, and the maintenance of constant river heights has reduced the natural wetting and drying cycles needed for many native plant and animal species to flourish.
Project details
The project involves:
- changing the operational rules to increase seasonal variability in the heights of the weir pools, creating intermittent inundations and exposure of wetlands, aquatic plant beds and floodplain vegetation
- the installation of regulators and fishways on existing fixed crest weirs to restore fast flowing habitat and hydrodynamic diversity (seasonal variability in flow and velocity within the waterway) to Carrs, Capitts and Bunberoo creeks, supporting fish breeding
- restoring fish passage between Lake Victoria and the Murray River through the construction of a fishway at the Frenchmans Creek inlet regulator, supporting fish breeding and the movement of fish from the lake back to the lower Murray.
The project will be managed along with other proposed changes in river operations and existing environmental infrastructure, such as The Living Murray works at Mulcra Island and proposed works at Wallpolla Island.
Project benefits
The works aim to generate significant environmental benefits including:
- better conditions for fish growth, breeding and dispersal
- increased habitat use and re-instated seasonal wetting and drying of the wetlands and floodplains
- improved water quality
- reduced water loss from the weir pools through evaporation in summer
- improved riverine habitat that will increase aquatic food resources and promote bird breeding.
This will be achieved by introducing a more natural watering regime, which will improve habitat productivity and quality, promote aquatic fauna and water bird use, encourage fish growth and reduce water losses from evaporation.
The project also aims to increase understanding of the Aboriginal cultural heritage of sites including Pigsfoot Lagoon and provide First Nations participation and employment opportunities.
Project status
The project is currently finalising approvals and procurement, with some early works now complete.
The early works include the replacement of the Millewa pump station on the banks of the Murray River, adjacent to Lock 9, which was officially opened in April 2024.
The pump station has been replaced with a contemporary design enabling water supply to continue and the Murray River weir pools to be seasonally varied for ecological improvements. It has been built thanks to a $3.5 million contribution from the Australian and NSW Governments under an agreed cost sharing arrangement with Lower Murray Water.
Early access road work is also underway with crushed rock being laid along tracks on the Carrs, Cappitts and Bunberoo floodplain to improve access to the building site during wet weather and to protect cultural artefacts from heavy construction vehicles.
Stakeholder and community engagement
The project is being managed collaboratively with stakeholders in New South Wales, South Australia and Victoria.
The lower Murray is rich in cultural and spiritual significance. The Traditional Owners, the Barkandji, Maraura and Kirra Tar Ru people, play a key role ensuring cultural considerations are made throughout the project in line with their Healthy Country Plan.
Modelling
Hydrologic and hydraulic modelling has been undertaken to inform the options assessment, design and operational planning stages for the project. Modelling has been fundamental to validating project feasibility, through considering designs, outcomes, costs and impacts, prior to commencing the design, submission and approval process.
Environmental planning and assessments
View the project's Environmental Planning and Assessment Regulation [Clause 171(4)] publications.
Report
Review of Environmental Factors for Carrs, Capitts and Bunberoo Creek systems released.
Frequently asked questions
Learn more about the project through these frequently asked questions and answers.
Historically there have been weir pool trials at Locks 7 and 8 through a coordinated approach between Victoria and New South Wales. These trials identified constraints to pursuing long-term changes to weir pool operations.
The Millewa pump station at Lake Cullulleraine was one of the constraints in the Lock 9 weir pool and this has now been addressed with the commissioning of a new facility. Although permanent operational rule changes are not yet signed off, the flexibility to trial proposed operational changes is now available for any planned environmental watering events.
Several investigations including third-party socio-economic and infrastructure impact studies have been conducted to inform the operating plan for Locks 8 and 9. It is likely that the approved lowering limit will be in the order of 400mm to 500mm lower than current fixed levels, with seasonal requirements expected to inform the operational settings for weir pool lowering.
The final operating plan will need to ensure a balance between ecological and socio-economic objectives can be achieved. Consultation is being conducted with identified stakeholders to assess the possible impact of any changes.
Any proposed changes to operation will need to be formally adopted under the provisions of the Murray-Darling Basin Agreement.
Investigations have been undertaken to determine the optimal operating regime for Locks 8 and 9. Operating principles will be required to allow for a wetting and drying regime providing flexibility to meet the water requirements of neighbouring ecosystems, as well as meeting the needs of downstream users (irrigators, towns and stock and domestic).
The range of considerations involved in future water level management will be documented in a Review of Environmental Factors to be finalised later in 2024.
Investigations have been completed to determine third-party socio-economic impacts associated with the proposed lowering of Locks 8 and 9. The information gathered during investigations identified around 7 boating access facilities, including the Fort Courage floating pontoon, that will be affected by varying operational water levels. Mitigation measures may be required at some of the sites and these are being discussed with the individual owners. The investigations confirmed that the proposed operational levels are unlikely to affect overall trafficability within the river throughout the Locks 8 and 9 weir pools.
An assessment of all pumps within the reaches of Locks 8 and 9 has been completed and the potential impacts the change to operational water levels may have on pump infrastructure has been communicated to affected holders of works approval licences. The project has and will continue to consult with water users prior to finalising a weir pool operating plan. Consultation will continue throughout the life of the project.
Options for the Frenchmans Creek fishway were identified and assessed with preference being for a vertical slot design. Key stakeholders from SA Water, Murray-Darling Basin Authority, the department's Environment and Heritage division, the Department of Primary Industries – Fisheries and other technical experts have been consulted on each option to determine the most suitable fishway design for this location.
The detailed reference design has been completed for a bypass regulator coupled with a vertical slot fishway. The design has been verified using a scale model developed by Manly Hydraulics Laboratory. Environmental and other statutory approvals are being finalised in the second half of 2024.
Works on the Carrs, Cappitts and Bunberoo Creek floodplain sites have been transferred to SA Water for construction commencing in late 2024.
Works associated with the Lake Victoria Inlet regulator are passing through final stages of approval and are expected to move into construction in 2025.
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Contact us
For more information call us on 1300 081 047 or email us at water.enquiries@dcceew.nsw.gov.au