Clutha River

Clutha River / Mata-Au
The Clutha River system.
Country	New Zealand
Basin features
River mouth	Pacific Ocean sea level
Basin size	21,960 km2 (8,480 sq mi)
Physical characteristics
Length	338 km (210 mi)
Discharge	Average rate: 614 m3/s (21,700 cu ft/s)

The Clutha River / Mata-Au is the second longest river in New Zealand and the longest in the South Island. It flows south-southeast 338 kilometres (210 mi) through Central and South Otago from Lake Wanaka in the Southern Alps to the Pacific Ocean, 75 kilometres (47 mi) south west of Dunedin. It is the highest volume river in New Zealand, and the swiftest, with a catchment of 21,960 square kilometres (8,480 sq mi), discharging a mean flow of 614 cubic metres per second (21,700 cu ft/s). The Clutha River is known for its scenery, gold-rush history, and swift turquoise waters. A river conservation group, the Clutha Mata-Au River Parkway Group, is working to establish a regional river parkway, with a trail, along the entire river corridor. The name of the river was changed to a dual name by the Ngai Tahu Claims Settlement Act 1998.

The ultimate source of the river is at the head of the Makarora River, close to the saddle of the Haast Pass, which flows into the northern end of Lake Wanaka. The southern end of the lake drains into the nascent Clutha close to Albert Town, where it is met by its first main tributary, the Hāwea River, the outflow of Lake Wanaka's twin, Lake Hāwea. It is also met here by the Cardrona River.

From here the river flows swiftly through the Upper Clutha Valley between ancient glacial terraces, negotiating a long section called the 'Snake' before reaching a rare switchback feature called the Devil's Nook near the town of Luggate. The river soon narrows as it passes through the Maori Gorge at Queensberry. Shortly thereafter it is joined by another tributary, the Lindis, before widening as it enters Lake Dunstan, an artificial lake created behind the massive hydroelectric dam at Clyde.