Cromwell is a town in Central Otago in the Otago region of New Zealand.
It is situated between State Highway 6 (linking to Wanaka, 50 km north, and Queenstown, 60 km west) and State Highway 8 leading to the Lindis Pass, 75 km northeast, and Alexandra, 33 km south. The road to Alexandra winds through the Cromwell Gorge.
In 1862 gold was discovered at the river junction, leading to the arrival of thousands of miners. After gold became scarce, the area became a centre of pastoral farming and stone fruit production. The latter is commemorated with the giant sculpture of stone fruit which stands outside the northern end of the town.
Cromwell formerly lay at the confluence of the Clutha River and Kawarau River, which was noted for the difference between the colours of the waters of the two rivers and also for the historic bridge at the convergence of the two.
Since the construction of the Clyde Dam and the filling of Lake Dunstan in the early 1990s the river confluence was drowned, as was the old town centre. In preparation for this, approximately one-third of the town was rebuilt on higher ground, including a new bridge, town centre, college, and civic amenities. Several of the old buildings of the town which escaped the flooding have been retained as a historic precinct close to the shore of the Kawarau.
It is unknown when and why the town was so named, although given the proximity of Naseby it is likely to have been named for Oliver Cromwell. The town was previously known as The Junction, The Point, or Kawarau.
According to the 2001 New Zealand Census of Population and Dwellings, the permanent resident population of Cromwell was 2667, an increase of 54 since 1996.
Nearby settlements are at Bannockburn, Lowburn, Tarras, and Ripponvale.
The Clyde Dam is New Zealand's third largest hydroelectric dam, and is built on the Clutha River, near the town of Clyde.
History
There was considerable controversy when the dam was planned as to whether it was needed, and 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 as of 2007 there are 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 landslides 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
