Hydro Tasmania said July 13 it plans to construct concrete buttresses to support Catagunya, a concrete gravity dam strengthened by steel cables. The utility said it is concerned that corrosion is weakening the cables, and that the buttresses would eliminate the need for the cables.
Hydro Tasmania submitted an application to the Assessment Committee for Dam Construction to carry out the work. It is to consult with all stakeholders prior to commencement of construction.
The work, estimated at A$25 million to A$30 million (US$21.7 million to US$26 million), is expected to begin in March 2008 and take 18 months for completion. During that period, Lake Catagunya will be lowered, with normal levels restored upon completion.
At the time of its construction in 1962, the 49-meter-tall Catagunya was the largest dam of its type in the world. Water from Lake Catagunya flows through a concrete flume and twin steel penstocks to two 24-MW Francis turbine-generators. Catagunya is one of 10 power stations in the Derwent River catchment, which provides 27 percent of Tasmania's electricity.