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
Silver Creek (American River) Silver Creek (American River) Silver Creek is a major tributary of the South Fork American River in the Sierra Nevada mountain range. It begins below the dam of Junction Reservoir where its two main tributaries meet — South Fork Silver Creek and Big Silver Creek. There are three reservoirs, all part of the Upper American River Project, along Silver Creek and its tributaries before the main stem empties into the South Fork American River just north of Pollock Pines. Ice House Reservoir lies along South Fork Silver Creek four miles northwest of Kyburz. Nine miles northwest of Kyburz is Union