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
South Fork American River in 2011. The river begins at Nebelhorn near Johnson Pass about south of Lake Tahoe. From there it flows west for , past the towns of Kyburz, Pollock Pines and Coloma, before emptying into Folsom Lake, the reservoir formed by the Folsom Dam. The North Fork American River also flows into the lake, and the combined rivers form the American River proper, which flows from the dam southwest to a confluence with the Sacramento River. The South Fork drains an area of , or about a third of the American River watershed. Major tributaries include Silver Creek, Rock Creek, Weber