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
Upper American River Project fish passage by the project's dams, which segment parts of the upper South Fork American River, the Rubicon River and their tributaries. Water is diverted from the Rubicon River to a storage reservoir, Loon Lake, from which it is released through the Loon Lake Powerhouse to Gerle Creek. This water is intercepted and diverted into Silver Creek, a tributary of the South Fork American River, flowing through the Robbs Peak Powerhouse into Union Valley Reservoir, the project's principal reservoir. Water from Ice House Reservoir also enters Union Valley via the Jones Fork Powerhouse. From Union Valley, water flows through the