CLYDE DAM

The 'Clyde Dam' is New Zealand's largest hydroelectric dam and was built along the Clutha River, near the town of Clyde.
There was considerable controversy when the dam was planned as to whether it was needed, and also because it would flood many houses and orchards upstream at Cromwell, as well as the scenic Cromwell Gorge, which was a highlight of the then young but growing New Zealand tourism industry. Construction would also require the closure of the Otago Central Railway beyond Clyde, though materials for the dam would provide significant traffic for the rest of the line, which was experiencing a drop in freight tonnage.
The dam was constructed, following the passing of enabling legislation, as part of Prime Minister Sir Robert Muldoon's Think Big projects of the late 1970s and early 1980s, creating Lake Dunstan. The power station has a capacity of four 120 MW francis turbines (for a total of 480MW), but is only allowed to run 432 MW due to resource consent conditions. The dam was built so that two further penstocks and turbines could be installed, but there are currently no plans to do so.
During construction, the adjacent rock was discovered to be microfractured, because of an earthquake faultline. A large amount of slurry cement was pumped into the rock to stop water leaks. This additional work was one reason for a major project cost over-run, which made the dam the most expensive in New Zealand. The other areas of over-run were due to stabilisation of land slides in the Cromwell Gorge. There are over 18 km of tunnels throughout the gorge for draining purposes. Because of all this extra work it overran the budget by nearly an extra 50% and delayed the filling of Lake Dunstan by a few years.