Lake Ruataniwha is an artificial lake in the Mackenzie Basin in the South Island of New Zealand. It was formed in 1977-1981 as part of the Waitaki hydroelectric project. It is located on the traditional border between the provinces of Canterbury and Otago, two kilometers north of Twizel. The lake takes its name from Ruataniwha Station, a large sheep farm in the area, part of which the New Zealand Department of Electricity acquired as a site for the Twizel settlement (founded in 1968). Ruataniwha was the Maori chief who sank when the shuttle Arai-te-ura sank Moeraki in the 12th century.Lake Ruataniwha, Twizel, New Zealand (with Map & Photos) (tourcounsel.com)
The lake is roughly 4.5 kilometres long and 3.4 square kilometres in size.
It was built between 1977 and 1981 by the New Zealand Ministry of Works as part of the Upper Waitaki Power Project in a valley caused by the hau River. The gorge was sealed by the construction of the Ruataniwha Dam, the crest of which carries State Highway 8 between Twizel and Omarama.
Lake Ruataniwha is fed by the Ohau power station’s output as well as an overflow discharge from Lake hau down the generally dry bank of the hau River.[ ] Lake Ruataniwha – Wikipedia
Before the dam could be built, the hau River was diverted by carving a route through a low, stony extension of the Benmore Range and installing three diversion gates there, which took 200,000 cubic metres of concrete. In August 1980, the hau River was diverted such that water would flow through Ohau A and then back down the river bed. Later that year, downstream of Ohau A, the river was diverted once more, this time away from its natural channel and through the finished gates. On its upstream and downstream sides, an earth dam with gravel shoulders was created. The main dam, which blocks the original river channel, is 240 metres long, while the wing dam adjacent to it is 480 metres long.[ ]Lake Ruataniwha – Wikipedia
The Ministry of Works transformed the lake into a major recreational resource for the area, complete with a huge number of trees and a holiday park on the lake’s shore. Ruataniwha is also a popular rowing location in New Zealand.
This was not planned as part of the hydroelectric project, but rather arose as a result of facilities being built as a public service on the instructions of Max Smith, the Upper Waitaki Power Project’s locally based Project Engineer. Before the lake was filled, the rowing course was surveyed, landscaping was completed, and anchors for lane markings were installed. He struck an arrangement with the Rowing Association to fund the construction of the regatta control facility.[ ] Lake Ruataniwha – Wikipedia
Image attribution: Photographer Unknown, U., (2021) Lake Ruataniwha. [ONLINE]. Available at: https://1.bp.blogspot.com/-yKpVYWQfmzo/YMLFZeG9YjI/AAAAAAAAPnE/P2l5OgEEbTQr5gPSfmpGRAxUg6oypEBIQCNcBGAsYHQ/s16000/lake-ruataniwha-3.jpg [Accessed 31 October 2021].
Image 2 attribution: Photographer Unknown, U., (2021) Lake Ruataniwha. [ONLINE]. Available at: https://1.bp.blogspot.com/-yKpVYWQfmzo/YMLFZeG9YjI/AAAAAAAAPnE/P2l5OgEEbTQr5gPSfmpGRAxUg6oypEBIQCNcBGAsYHQ/s16000/lake-ruataniwha.jpg [Accessed 31 October 2021].
Image 3 from: See the south Island. 2021. Lake Ruataniwha, Mackenzie Basin. [ONLINE] Available at: https://seethesouthisland.com/lake-ruataniwha-mackenzie-basin-new-zealand/. [Accessed 31 October 2021].