Located in Tasmania's remote southwest within the Tasmanian Wilderness World Heritage Area (TWWHA), the project combined complex engineering with careful environmental management to improve the dam's resilience while protecting one of Australia's most environmentally significant landscapes.

Building a safer, more resilient dam

The primary objective of the Edgar Dam upgrade was to strengthen the dam against seismic activity. While the risk of a major earthquake on the nearby Lake Edgar Fault is extremely low, the completed works further enhance the dam's ability to withstand such an event, ensuring the ongoing safety and reliability of Hydro Tasmania's renewable energy assets.

The upgrade included:

• Construction of a filter buttress along the downstream face of the dam.
• Installation of a low height crest wall.
• Sealing works on the upstream side of the dam.

These improvements are the result of more than a decade of planning, investigation, design, and construction.

A collaborative Tasmanian success story

The project was delivered through a partnership between Hydro Tasmania, its consulting business Entura, and Tasmanian civil construction company Hall Earthmoving, which served as the head contractor.

Hydro Tasmania CEO Rachel Watson praised the collaborative effort that enabled the project to finish ahead of schedule.

"Completing the Edgar Dam upgrade four months ahead of schedule is an outstanding result and reflects the skill, commitment and collaboration of Hall Earthmoving and the project team." 

She added that the completed works provide even greater confidence in the dam's resilience in the highly unlikely event of a major earthquake.

Delivering real benefits for Tasmania

Beyond strengthening critical infrastructure, the project delivered a substantial boost to the Tasmanian economy.

More than 95 per cent of the project's budget was spent within Tasmania, supporting local contractors, suppliers and specialist businesses throughout the project's lifecycle.

"Projects like this support local jobs, skills and businesses while delivering long-term benefits for Tasmania's renewable energy future,” Rachel Watson said.

(Works throughout the project)

Protecting a World Heritage environment

Working within the TWWHA required rigorous environmental planning and management throughout construction.

The project was referred under the Federal Government's Environmental Protection and Biodiversity Conservation Act to ensure environmental impacts were carefully assessed and minimised.

Environmental protection measures included:

• Vehicle and machinery washdown facilities to prevent the spread of weeds and pathogens.
• Restrictions on vehicle movements during certain periods to protect threatened wildlife.
• Continuous water quality monitoring and management throughout construction.

"Working in such a sensitive environment required careful planning and a strong commitment to protecting the World Heritage Area's natural values,” Rachel Watson said.

What's next?

With the major construction works now complete, the project enters its final phase. Hydro Tasmania will focus on demobilising the site and reinstating and rehabilitating the Edgar Dam Campground.

The successful completion of the Edgar Dam upgrade highlights how infrastructure projects can simultaneously improve public safety, support local industry, and protect the natural environment. It also reinforces Hydro Tasmania's ongoing commitment to maintaining reliable renewable energy infrastructure for generations to come.