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
Des Moines River from St. Paul, Minnesota to St. Louis, Missouri, passes over this section; the highway is designated Route 27 in both Iowa and Missouri, and was completed in the early 21st century. The Des Moines River rises in two forks. The West Fork (the main branch) rises out of Lake Shetek in Murray County in southwestern Minnesota. It flows south-southeast into Emmet County, Iowa, past Estherville. The East Fork rises out of Okamanpeedan Lake in northern Emmet County on the Iowa-Minnesota border and flows south, through Algona. The two forks join in southern Humboldt County, approximately 5 miles (8 km) south