Many of the largest dams and reservoirs in New Zealand have been developed principally to produce hydroelectricity. Other uses include irrigation and municipal water supply.
The river was developed in multiple stages. The Waitaki Dam was built first, without earthmoving machinery, followed by the development of the Aviemore Dam on Lake Aviemore and Benmore Dam on Lake Benmore. Lake Pukaki was initially dammed at this stage to provide storage and flow control. A small station was also installed on Lake Tekapo, but although it has a small dam to raise the pre-existing lake, water was taken through a 1.6 km (1 mi) tunnel to a powerstation below the level of the lake.
In the 1960s, work was started on the Upper Waitaki project. This project consisted of taking the discharge from the original Tekapo (A) station through a power canal, the Tekapo Canal, to Tekapo B station at the edge of Lake Pukaki. The dam at Pukaki was increased in height. Water from Pukaki is then transferred into the Pukaki Canal which meets the Ōhau Canal from Lake Ōhau into Ōhau A station and Lake Ruataniwha. The Ōhau Canal continues beyond Lake Ruataniwha to Ōhau B midway along, before emptying through Ōhau C into Lake Benmore.
The stations are (capacity) (annual output) (commissioned)
Tekapo A (25 MW) (160 GWh) 1955
Tekapo B (160 MW) (800 GWh) 1977
Ōhau A (264 MW) (1150 GWh) 1980
Ōhau B (212 MW) (970 GWh) 1984/1985
Ōhau C (212 MW) (970 GWh) 1984/1985
The original Waitaki power stations discharge water back into the Waitaki River which then forms a storage lake for the next station in the chain.
The three power stations are:
Project Aqua was a proposed scheme of six dams on a man made canal running from the Waitaki Dam to the sea. It was cancelled by Meridian Energy on 29 March 2004.
Manapouri does not rely on a high dam to provide water – it takes advantage of the natural 178-metre height difference between Lake Manapouri and the sea at Deep Cove in Doubtful Sound, in Fiordland. The power house is in a cavern, while two tailrace tunnels take the water from the power house 10 km (6 mi) to Deep Cove and the sea. The Manapouri Control Structure (Mararoa dam) downstream from the original outlet of Lake Manapouri controls the lake level, and feeds water from the Mararoa river back up the river into the Lake.
^ abcdefghijklmnopOffer, R.E. (Robert) (1997). Walls for Water: Pioneer Dam Building in New Zealand. Palmerston North: The Dunmore Press Ltd. ISBN0-86469-313-3.
^IPENZ Engineers New Zealand, Engineering Heritage Register,Morton Buttress Dam of 1911, retrieved 29 December 2010.
^IPENZ Engineers New Zealand, Engineering Heritage Register,Lower Karori Dam, retrieved 29 December 2010.
Further reading
Offer, R.E. (Robert) (1997). Walls for Water: Pioneer Dam Building in New Zealand. Palmerston North: The Dunmore Press Ltd. ISBN0-86469-313-3. Retired civil engineer and dam inspector examines the development of New Zealand dam construction techniques and uses from the 1860s to the 1950s for municipal water supply, mining, kauri logging and development of the Lake Waikarimoana Natural Dam for hydroelectric power.