The Tekapo River flows occasionally 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...

, 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. The lower reaches (below the Merryburn confluence) are popular with Anglers chasing brown and rainbow trout although the recent infestation by the invasive algae Didymosphenia geminata

Didymosphenia geminata

Didymosphenia geminata, commonly known as didymo or rock snot, is a species of diatom that grows in warm and shallow water. If it overgrows, it can form large mats on the bottom of lakes, rivers and streams. It is not considered a significant human health risk, but it can affect stream habitats and...

 'Didymo' has somewhat limited angling opportunities.
Originally, the river flowed southwest for 50 kilometres from the southern end of Lake Tekapo before joining with the Pukaki River

Pukaki River

The Pukaki River flows through the Mackenzie Basin, Canterbury, in New Zealand's South Island.Originally, the river flowed southwest for 15 kilometres from the southern end of Lake Pukaki before joining with the Tekapo River and flowing into the northern end of Lake Benmore...

 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, the water from Lake Tekapo is now diverted via a canal to Lake Pukaki

Lake Pukaki

Lake Pukaki is the largest of three roughly parallel alpine lakes running north-south along the northern edge of the Mackenzie Basin on New Zealand's South Island. The others are Lakes Tekapo and Ohau...

 as part of the Waitaki Hydroelectric scheme. These lakes are used to store water, and occasionally during a particularly heavy snow melt or if the power stations or canal need servicing, water may be spilt from either the dam or canal back into the riverbed. These events are much anticipated by kayak

Kayak

A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...

ers, to the extent that they have been known to re-shape parts of the riverbed to create 'better' rapids.