Traffic and wildlife impacts

    Traffic on the Lyell Highway

    Area of interest: impact of construction traffic. 

    Construction will generate additional traffic movements on the Lyell Highway and short delays. A Traffic Impact Assessment is underway to quantify potential impacts on the road network and identify how impacts can be managed.


    Area of interest: potential increase in risks to wildlife due to increased traffic movements.

    This was identified as a potential impact as part of our studies and we will adopt measures to minimise impacts on all wildlife through our environmental mitigation strategies.

    Lake access and storage levels

    Access to lakes for recreation

    Area of interest: impact on water-based recreation activities.

    There will be no change to existing public access to lakes in the Tarraleah scheme for activities such as fishing and boating.  For safety and operational needs, a new exclusion zone will be created around the new Lake King William intake. 

    Storage levels and river flows

    Area of interest: potential impacts on the Derwent River and lake storage levels.

    We’ve done extensive water modelling, including modelling of River Derwent flows and water levels of scheme storages. The existing operational range of storages will not change. Hydro Tasmania is investigating flow releases below Clark Dam, to maintain downstream environmental values.

    Cultural heritage

    Cultural heritage

    Area of interest: respecting and listening to Tasmanian Aboriginal communities.

    We are very interested in acknowledging and respecting the cultural heritage values and connections of First Nations peoples to the area. We are working to develop culturally sensitive ways of listening to, working with First Nations peoples, and planning for outcomes in this important area.

    World Heritage and historical values

    World Heritage values

    Area of interest: potential impacts on the Tasmanian Wilderness World Heritage Area (TWWHA).

    A range of studies has shown the project won’t significantly impact the natural and cultural heritage values of the TWWHA. We’ve done a visual impact assessment to look at how infrastructure (such as the surge tower) will sit in the landscape and how the construction footprint may be viewed from the TWWHA. Overall, the visual impact is considered low.

    Historic values

    Area of interest: history of the scheme and what is planned for the original Tarraleah assets.

    Working closely with Heritage Tasmania, the community and stakeholders, we’re looking into how heritage buildings and assets might be re-used in future to ensure heritage values are protected and preparing a decommissioning plan for infrastructure no longer required.

    Benefit sharing opportunities

    Benefits sharing

    Area of interest: building economic, social and environmental resilience.

    We’re committed to ensuring local communities and businesses can benefit from the project. Social procurement and local content requirements are being developed and we’re working with community, business and government stakeholders to identify initiatives that could provide economic, social and environmental benefits. We encourage you to get involved!

    Workforce accommodation in future

    Workforce accommodation

    Area of interest: future use of Tarraleah village and accommodation for the construction workforce.

    We recently purchased the village and it will remain open to the public until its full capacity is needed for the construction workforce, alongside new accommodation. During construction, there will be changes in access in and around the village.

    Current upgrade works

    Why is a new intake part of the upgrade works?

    This work suits a range of future scenarios for the scheme.

    The existing conveyances (No 1 and No 2 canal) are ageing and will need to be replaced with a new single conveyance in the future, regardless of a potential future redevelopment. 

    Upgrading the conveyance would require a new intake on Lake King William, which is one of the works packages being progressed. The work will also address limitations of the existing ageing assets.

    The location for the proposed intake is in a bay ~1 km north east of Clark Dam.  

    If a Final Investment Decision is not reached in future on a potential redevelopment, these works will support the conveyance upgrade to ensure the scheme can continue to operate safely and reliably into the future.

    Why does Mossy Marsh Dam need to be upgraded?

    The works on Mossy Marsh Dam are to improve the dam safety position of the existing embankment and provide a controlled and safe spillway location to pass extreme rainfall events. 

    This work suits a range of future scenarios as it will ensure the safe and reliable continued operation of the existing scheme and support a potential future redevelopment which may see changed operational requirements for Mossy Marsh Pond. 

    These current works don’t affect or change the way water is managed in Mossy Marsh. 

    There will also be upgrade works to Butlers Gorge Road, including new culverts, to maintain access in flood conditions.

    Our upgrade works to Mossy Marsh Dam have reached practical completion, however, public access remains closed to allow the area to rehabilitate. We expect the site to be re-opened for anglers and other recreational users in time for the 2023/24 fishing season opening in early August 2023.

    Access to Lake King William

    Where possible, we have sought to minimise impact to users in the area. But for safety reasons, we do need to temporarily change access around the construction sites.

    • Public access to Mossy Marsh Dam is closed for safety reasons during construction works, which started on 15 August. Our upgrade works have reached practical completion, however, public access remains closed to allow the area to rehabilitate. We expect the site to be re-opened for anglers and other recreational users in time for the 2023/24 fishing season opening in early August 2023. 
    • There will be changes to Switchyard Track access for an extended period to the end of 2024 when we expect that work on the new intake structure construction will be finished.

    You can still be able to access the public boat ramp at Lake King William.

    The campground at Lake King William is closed during the Lake King William Intake works.

    Butlers Gorge Road closed weekdays from 26 June

    Our teams are continuing works for construction of a new water intake at Lake King William. A new phase of activity for the connecting tunnel has kicked off and there will be increased heavy vehicle activity on the road. To ensure public safety, Butlers Gorge Road (from the Lyell Highway turnoff) will be closed on weekdays from Monday 26 June until 4 August between 7am and 5pm.

    The lookout and boat ramp are accessible outside of these closure times and also on weekends. We expect to restore full access to these areas in time for the start of the fishing season.

    The future redevelopment of Tarraleah

    As part of our commercial assessment, we will be consulting with the community about a range of things including:

    • studies we are doing to understand potential impacts and how they can be mitigated (traffic and noise, visual impact, environmental impacts)
    • the environmental approvals process at a Federal, State and Local level.

    As our studies progress in 2023, seeking your views will be important input to our decisions. We want to better understand from the community any potential concerns or issues you have about what is proposed and how potential impacts can be mitigated. 

    As we progress the environmental approvals process at a Federal level, project information will be published to give local authorities and the community the opportunity to comment. 

    The EPBC Referral period for public comment has now closed. The Department of Climate Change, Energy, Environment and Water (DCCEEW) will now continue its assessment process. You can track progress through the assessment process at the EPBC Act Public Portal(External link) (the reference is EPBC Number: 2023/09482).

    We’re also required to seek approvals at a state and local level:

    • various state level environmental approvals
    • state parliamentary approval to construct a new hydropower asset (the power station)
    • local council approval for a scheme development application (DA) as well as building approval for various parts of the scheme.

    We are currently progressing our commercial viability of redeveloping the scheme and expect to reach a Final Investment Decision by the end of 2024.

    Marinus Link

    Marinus Link will open up even greater two-way energy market access, to take advantage of Tasmania’s abundant renewable energy potential in wind and hydropower.  

    Marinus Link unlocks the opportunity for our Battery of the Nation projects, which will boost Tasmania’s hydropower capacity and add long-duration pumped hydro storage.

    Benefits will flow back to Tasmania through access to affordable power, economic investment, creation of much needed jobs, attraction of new business, and returning revenue to the state government to support vital infrastructure and services.