Jamanxim River Jamanxim River The Jamanxim River is a river of Pará state in north-central Brazil. Originating in the Serra do Cachimbo, it is a tributary of the Tapajós, into which it flows a few kilometers upstream from Itaituba. The river flows through the Tapajós-Xingu moist forests ecoregion. It flows through the Itaituba I National Forest, a sustainable use conservation area established in 1998. The river basin also contains part of the Rio Novo National Park, a conservation unit created in 2006. Its hydroelectric potential, along with that of the Tapajós, was assessed by Eletronorte (Centrais Elétricas do Norte do Brasil S.A.),
Xingu-Tocantins-Araguaia moist forests many smaller blackwater rivers including the Pacajá and Anapu tributaries of the Amazon River, the Bacajá and Fresco tributaries of the Xingu, and the Parauapebas and Catete tributaries of the Tocantins. The ecoregion is in the neotropic ecozone and the tropical and subtropical moist broadleaf forests biome. The Köppen climate classification is "Am": equatorial, monsoonal. Temperatures are fairly steady throughout the year, slightly higher in April and slightly lower in July. Average temperatures range from , with a mean of . The region is drier than the ecoregions further to the west. In the middle Xingu annual rainfall is .