Iriri River Iriri River The Iriri River () is a large tributary of the Xingu River in Brazil, in the state of Pará. It is long making it the 116th longest river in the world (with Krishna River, India) and the 15th longest in the Amazon basin. The headwaters are the traditional home of the Panará people. The river rises in the Nascentes da Serra do Cachimbo Biological Reserve, a strictly protected conservation unit established in 2005 in the Serra do Cachimbo. It is one of the headwaters of the Xingu River. It flows for before joining the Xingu, running through the
South Fork American River Creek, and Silver Fork American River. Most of the watershed consists of high, forested mountains and steep-sided valleys that receive up to of annual precipitation, except for the westernmost section which consists of drier foothill country. The river also contributes about a third of the total outflow of the American River system. According to a U.S. Geological Survey stream gage at Lotus, about above Folsom Lake, the average discharge was from 1951 to 1995. The highest recorded flow was on January 1, 1997 (see ), and the lowest monthly mean was in July 1977. Rafting and Kayaking The South Fork