Hydro Tasmania last year applied to the Assessment Committee for Dam Construction for permission to perform the work and is consulting with stakeholders prior to starting construction. (HNN 7/13/07)
The utility 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.
"We have decided to refurbish Catagunya Dam as we could no longer be 100 percent sure of the condition of the original steel anchor cables," Hydro Tasmania Chief Executive Officer Vince Hawksworth said August 29.
The work is expected to 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.