In 1977 the catch-cry was "Think Big" when the New Zealand Government decided to start building the Clyde Power Station.
The largest concrete dam in the country also became 'big' in controversy and no other Government project had ever generated such staunch opposition or support. Nevertheless, the Clyde Power Station today stands as a monument to progress in this country... progress that has come about through the modifications demanded by the public, but still allowing it to provide enough power to supply both Christchurch and Dunedin.
Completed in 1993, the Clyde Power Station is the largest concrete gravity dam in the country. One million cubic metres of concrete was poured to construct the dam, with another 200,000 cubic metres used to construct the dam’s power station. The Clyde Power Station is both a marvel of modern engineering and a critical piece of New Zealand’s electricity system – generating the large amounts of renewable energy that New Zealand needs.
Construction of the Clyde Dam was a controversial project. Built by the New Zealand government, construction at Clyde began in 1979, and peaked in 1986 and 1987 with about 1000, workers on site. The challenge at Clyde was ensuring the stability of the land behind the dam surrounding Lake Dunstan. Extensive geological investigations and engineering works were carried out, including 18 kilometres of tunnels dug into the hillsides to drain and stabilise them. Huge buttresses of compacted rock and gravel were built to stabilise the hillsides, and 6,500 measuring and monitoring instruments were installed around the lakeshore.
To minimise the environmental impact of the power station, Lake Dunstan operates in a narrow band from 193.5 to 194.5 metres above sea level. Lake Dunstan does not have a large amount of storage capacity, with the Clyde Power station relying mainly on the run of the river for its generating power. The average flow past the dam each day therefore generally reflects the natural flow of the Clutha and Kawarau Rivers where they feed into Lake Dunstan.
The Clutha catchments include Lake Wakatipu and Lake Wanaka, which provide uncontrolled flows, and Lake Hawea, which provides storage of water, managed by the Hawea control gates.
The Clyde Power Station began generating electricity during the 1992 power crisis, though the lake did not reach its full operating level until September 1993.
The Clyde Power Station is owned and operated by Contact Energy Limited.
Contact details are:
Post – P O Box 10742, The Terrace, WELLINGTON 6143
Generation Engineer, Clyde Power Station, P O Box 25, CLYDE