Tasmanian Divers Group was engaged by Hall Earthmoving to provide commercial diving services as part of the Edgar Dam Safety Upgrade for Hydro Tasmania. The project involved the installation of a new external waterstop system along the upstream face of Edgar Dam to improve the integrity of the cut-off wall and reduce water ingress.

Located within the Tasmanian Wilderness World Heritage Area, Edgar Dam is an extremely remote asset requiring detailed logistical planning and careful environmental management. TDG deployed sediment control measures and adapted construction methodologies to minimise environmental impacts while undertaking works within this sensitive environment.

The works combined above and underwater construction activities, including high-pressure water jetting, hydraulic grinding and drilling, sediment removal, underwater concrete preparation, installation of fixing systems and placement of the external waterstop system. Additional works included deployment of environmental controls, underwater rock removal, rigging operations and construction of reinforced concrete sections around the riparian outlet structure.

The project required close collaboration with Hall Earthmoving, Hydro Tasmania and the project engineering team to develop practical installation methods while maintaining compliance with the design intent. Working in an exposed remote environment with cold water, changing weather conditions and limited site access, TDG successfully delivered the project while maintaining the required environmental and quality standards.

The Edgar Dam Safety Upgrade demonstrates TDG's capability to deliver complex underwater construction and dam rehabilitation projects in remote and environmentally sensitive locations, supporting the long-term integrity of critical water infrastructure.