Lake Ōhau in the context of Huxley River

The Waitaki River is a large braided river in the South Island of New Zealand. It drains the Mackenzie Basin and runs 209 kilometres (130 mi) south-east to enter the Pacific Ocean between Timaru and Oamaru on the east coast. It starts at the confluence of the Ōhau and Tekapo rivers, now at the head of the artificial Lake Benmore, these rivers being fed by three large glacial lakes, Pukaki, Tekapo, and Ōhau, at the base of the Southern Alps. The Waitaki flows through Lake Benmore, Lake Aviemore and Lake Waitaki, these lakes being contained by the hydroelectric dams of Benmore Dam, Aviemore Dam and Waitaki Dam. The Waitaki has several tributaries, notably the Ahuriri River and the Hakataramea River. It passes Kurow and Glenavy before entering the Pacific Ocean. The river lends its name to the Waitaki District on the south side of the river.

The river's flow is normally low in winter, with flows increasing in spring when the snow cloaking the Southern Alps begins to melt, with flows throughout the summer being rainfall dependent and then declining in the autumn as the colder weather begins to freeze the smaller streams that feed the catchment. The median flow of the Waitaki River at Kurow is 356 cubic metres per second (12,600 cu ft/s).

Lake Pukaki (Māori: Pūkaki) 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 Ōhau. All three lakes were formed when the terminal moraines of receding glaciers blocked their respective valleys, forming moraine-dammed lakes. The Alps2Ocean mountain bike trail follows the edge of Lake Pukaki for part of its length.

Lake Tekapo (Māori: Takapō) is the second-largest of three roughly parallel lakes running north–south along the northern edge of the Mackenzie Basin in the South Island of New Zealand (the others are Lake Pukaki and Lake Ōhau). It covers an area of 83 km (32 sq mi) and is at an altitude of 710 m (2,330 ft) above sea level.

The Hopkins River (Māori: Te Awa Aruhe) is in the central South Island of New Zealand. It flows south for 45 kilometres (28 mi) from the Southern Alps / Kā Tiritiri o te Moana into the northern end of Lake Ōhau in the Mackenzie Country.

Its headwaters, on the southern slopes of Mount Hopkins, form the northernmost point of Otago, and the river's braided valley is part of the border between Otago and Canterbury. The river's main tributary is the Dobson River.