Amazon river dolphin widespread river dolphins. They are present in six countries in South America: Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela, in an area covering about . The boundaries are set by waterfalls, such as the Xingu and Tapajós rivers in Brazil, as well as very shallow water. A series of rapids and waterfalls in the Madeira River have isolated one population, recognized as the subspecies "I. g. boliviensis", in the southern part of the Amazon basin in Bolivia. They are also distributed in the basin of the Orinoco River, except the Caroni River and the upper Caura River in Venezuela. The
American River habitat. Nimbus Dam is downstream from Folsom Dam and helps to stabilize peaking power releases from Folsom Dam, and divert water into the Folsom South Canal for irrigation. Eight hydroelectric plants on the South Fork are operated by Sacramento Municipal Utility District (SMUD) as the Upper American River Project. These plants are fed by a series of reservoirs including Loon Lake, Ice House Reservoir and Union Valley Reservoir. With the exception of Folsom Lake, Union Valley is the largest in the American River watershed, storing of water. The Upper American River Project produces 1.8 billion kilowatt hours in an average