à Âhau A is a hydroelectric power station in the Mackenzie Basin, Canterbury, New Zealand. Operated by Meridian Energy, it is one of the three à Âhau stations in the Upper Waitaki hydro scheme. The station is located at the end of the man-made Pà «kaki canal, where water from Lake Pà «kaki joins flows from the à Âhau canal before passing through the station into Lake Ruataniwha.
à Âhau A was the third station built as part of the Upper Waitaki hydro scheme. The wider scheme began in 1968, and Twizel was established as a construction town for the project. Construction of à Âhau A began in 1971 and the station was commissioned in 1979.
During construction, approximately 2 million cubic metres of rock and gravel were excavated from the northern bank of the à Âhau River, and a further 500,000 cubic metres were removed for the tailrace tunnel. The Upper Waitaki works also altered the hydrology of the Mackenzie Basin by combining waters from Lakes Tekapo, Pà «kaki and à Âhau, and by creating Lake Ruataniwha with a dam on the à Âhau River.
A rowing course was also developed on Lake Ruataniwha during the project, and the lake later became a national rowing venue.
à Âhau A has four 66-megawatt generating units with a total installed capacity of 264 MW. It forms part of the Upper Waitaki hydro scheme, which includes the three à Âhau stations, the two Tekapo stations, two dams and six canals.