Hydro Tasmania has completed a $2.5m upgrade of the trash screen at the intake of Trevallyn Power Station, installing a new structure without draining the lake.
After weeks of preparation, the new trash screen – measuring 14m high and 12m wide – was installed in eight pieces, replacing a 30-year-old unit.
Engineering consultancy Entura developed an installation method that avoided draining Lake Trevallyn.
A specialist diving team from Tasmanian Divers Group removed the old screen and installed the new one underwater. A crane lowered each section to the divers, who positioned them in place.
“The project staff worked closely with our community engagement team to reduce impacts. Lake Trevallyn is a shared resource, and this approach has ensured water continued to be available for drinking, farming and recreational use,” said Hydro Tasmania Executive General Manager Assets and Infrastructure Jesse Clark.
He said the installation was technically demanding, with divers required to carry out multiple roles in low-visibility conditions: “The diving team has done an incredible job. Everything takes longer underwater, and they can’t see much further than half a metre in front of them.
“The divers wear a lot of hats. If you did this work on land, you’d have separate people doing each job. The divers have to do everything – they’re riggers, fitters, welders and surveyors.”
Local contractors including The Engineering Company, which manufactured the screen, and Billings Cranes, which handled lifting operations, were involved in the project.
The steel structure has been coated with a protective paint system designed to extend its lifespan from 20 years to 40 and reduce corrosion.
