Alps rivers such as the Danube have major tributaries flowing into them that originate in the Alps. The Rhône is second to the Nile as a freshwater source to the Mediterranean Sea; the river begins as glacial meltwater, flows into Lake Geneva, and from there to France where one of its uses is to cool nuclear power plants. The Rhine originates in a 30 square kilometre area in Switzerland and represents almost 60 percent of water exported from the country. Tributary valleys, some of which are complicated, channel water to the main valleys which can experience flooding during the snow melt
Puelo River course of the Ventisquero River. Traidor River rises in Hornopirén National Park. A large northern tributary of the Puelo, the Manso, has its sources in Mascardi Lake and other lakes and streams south-east of the Cerro Tronador, also in Argentina, and flows south-west through the Andes to unite with the Puelo a few kilometers west of the 72nd meridian. Puelo river's lower course is impeded in such a manner as to form three small lakes, called Superior, Inferior and the Tagua Tagua Lake. Puelo River The Puelo River has its origin in Lake Puelo in Argentine, and flows north-west through