Water in New Zealand and are of varying types and origins. Many of the lakes in the central North Island area are volcanic crater lakes, while the majority of the lakes near the Southern Alps were carved by glaciers. Hydroelectric reservoirs are common in South Canterbury, Central Otago and along the Waikato River. Over 180,000 kilometres of rivers has been mapped in New Zealand, the longest being the Waikato River with a length of 425 kilometres and the largest river by volume is the Clutha River with a mean discharge of 533 cubic metres per second. New Zealand has many notable waterfalls, some of
Clutha River events, and Lake Dunstan is an important rowing venue. Several major ski courses are found close to the river. Curling is also played close to the Clutha in the harsh Central Otago winters. Clutha River The Clutha River / Mata-Au 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 Wanaka 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