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
Xingu River in the Xingu River Basin and it is estimated that the total is around 600 fish species, including many endemics. At least 193 fish species living in rapids are known from the lower Xingu, and at least 26 of these are endemic. From 2008 to 2018 alone, 24 new fish species have been described from the river. Many species are seriously threatened by the dam, which will significantly alter the flow in the Volta Grande rapids. In the Upper Xingu region was a highly self-organized pre-Columbian anthropogenic landscape, including deposits of fertile agricultural terra preta, black soil in Portuguese, with