Hydro Tasmania has marked a major milestone on the upgrade to its Tarraleah hydropower scheme, with excavation works on the intake tower now complete.
Almost a quarter of a million cubic metres of rock and soil were removed to create the deep excavation where the new concrete tower will be constructed. Tasmanian company, Hazell Bros Group, delivered the works over the past 27 months.
An innovative plastic concrete cut-off trench was designed by Entura. The trench protects the deep excavation from seepage from the mighty waters of Lake King William. It also provides flexibility for construction and timing of future works associated with the intake excavation.
Hydro Tasmania Interim Executive General Manager, Construction, Tammy Chu, said it was an exciting time for the upgrade works project.
“This has been an impressive effort, removing 240,000m3 of rock and soil and using 3700 rock bolts – some up to 6m long.
“We overcame challenges with complex geology and typical Tassie winter weather. Plus local jobs were created, with a peak workforce of 30 people on the ground delivering this work,” she said.
The intake tower construction is the next planned phase of work. A tender for the intake tower construction was recently released, marking another major project milestone.
Designed by Entura, the intake project includes a 30m-high concrete structure housing intake screens, a large steel gate and associated hydraulic hoist.
Work on the 950m connecting tunnel is also well advanced. It will connect the new intake to a future new conveyance to feed water into Tarraleah Power Station. Hazell Bros Group is working alongside tunnelling experts, Tunnelling Solutions, to complete around 260 blasts, removing 100,000t of material along the tunnel length.
Hydro Tasmania said these are important upgrades on a scheme that has been delivering clean energy to Tasmania since the 1930s, making it one of the utility’s oldest schemes.
“Hydro Tasmania is proposing a major redevelopment, so Tarraleah will be ready to help meet the growing demand for energy and power the state for generations to come,” Ms Chu said.
The Federal Government has committed up to $65 million in funding for the upgrade works.
