The Tasman River is an alpine

Alpine climate

Alpine climate is the average weather for a region above the tree line. This climate is also referred to as mountain climate or highland climate....

 braided river

Braided river

A braided river is one of a number of channel types and has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars or, in British usage, aits or eyots. Braided streams occur in rivers with high slope and/or large sediment load...

 flowing through 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...

.

The river's headwaters

Source (river or stream)

The source or headwaters of a river or stream is the place from which the water in the river or stream originates.-Definition:There is no universally agreed upon definition for determining a stream's source...

 are in Aoraki/Mount Cook National Park

Aoraki/Mount Cook National Park

Aoraki/Mount Cook National Park is in the South Island of New Zealand near the town of Twizel. Aoraki/Mount Cook, New Zealand's highest mountain and Aoraki/Mount Cook village lie within the park...

, where it is the outflow of the Tasman

Tasman Glacier

The Tasman Glacier is the largest of several glaciers which flow south and east towards the Mackenzie Basin from the Southern Alps in New Zealand's South Island. It is New Zealand's longest glacier.-Geography:...

 and Murchison Glacier

Murchison Glacier

The Murchison Glacier is an long glacier flowing through Aoraki/Mount Cook National Park in the South Island of New Zealand. Lying to the east of Aoraki/Mount Cook, high in the Southern Alps, it flows southwestwards. The Murchison River, which takes its meltwater, flows under the larger Tasman...

s and also, via a short tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

, of the Hooker

Hooker Glacier

Hooker Glacier is one of several glaciers close to the slopes of Aoraki/Mount Cook in the Southern Alps of New Zealand. Though not as large as its neighbour, the Tasman Glacier, it is still impressive, and is some 11 kilometres in length...

 and Mueller Glacier

Mueller Glacier

The Mueller Glacier is a long glacier flowing through Aoraki/Mount Cook National Park in the South Island of New Zealand. It lies to the south of Aoraki/Mount Cook, high in the Southern Alps, and flows north...

s.

It flows south for 25 kilometres from the Southern Alps

Southern Alps

The Southern Alps is a mountain range extending along much of the length of New Zealand's South Island, reaching its greatest elevations near the island's western side...

 into the top end of the glacial lake Pukaki, this forming part of the ultimate headwaters of the Waitaki hydroelectic scheme.