The Clutha River (, officially gazetted as Clutha River / ) is the second longest river in New Zealand and the longest in the South Island. It flows south-southeast through Central and South Otago from Lake Wānaka in the Southern Alps to the Pacific Ocean, south west of Dunedin. It is the highest volume river in New Zealand, and the swiftest, with a catchment of , discharging a mean flow of . The river is known for its scenery, gold-rush history, and swift turquoise waters. A river conservatio…