The Pukaki River flows through the Mackenzie Basin

Mackenzie Basin

The Mackenzie Basin , is an elliptical intermontane basin, located in the Mackenzie and Waitaki Districts, near the centre of the South Island of New Zealand. It is the largest such basin in New Zealand...

, Canterbury

Canterbury, New Zealand

The New Zealand region of Canterbury is mainly composed of the Canterbury Plains and the surrounding mountains. Its main city, Christchurch, hosts the main office of the Christchurch City Council, the Canterbury Regional Council - called Environment Canterbury - and the University of Canterbury.-...

, in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

's South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

.

Originally, the river flowed southwest for 15 kilometres from the southern end of Lake Pukaki before joining with the Tekapo River

Tekapo River

The Tekapo River flows occasionally through the Mackenzie Basin, Canterbury, in New Zealand's South Island, although the riverbed is now often dry in the upper reaches it maintains a constant flow below the confluence of several tributaries notably the Merryburn, Forks, and Greys streams...

 and flowing into the northern end of Lake Benmore

Lake Benmore

Lake Benmore is a lake located in the South Island of New Zealand. It was artificially created in the 1960s by construction of Benmore Dam. The lake covers an area of approximately 75 km²...

. However, all water from Lake Pukaki is now diverted into a canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

 which is fed through three hydroelectric stations before being returned directly into Lake Benmore, as part of the Waitaki Hydroelectric scheme. Occasionally, water may be spilled down the riverbed when Lake Pukaki reaches its maximum height, or if a canal or power station requires servicing.

In 2010, Meridian Energy

Meridian Energy

Meridian Energy Limited is a New Zealand state-owned electricity generator and retailer. The company generates the largest proportion of New Zealand's electricity, generating 32 percent of the country's electricity in the year ending 31 December 2009, and is the fourth-equal largest retailer, with...

applied for resource consents to build a 35 MW power station at Pukaki's gate 18.