The Uatumã River (sometimes spelled Uatamã) is a

river A river is a natural flowing watercourse, usually freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the ...

flowing through the state of Amazonas in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. It is a northern

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainag ...

of the Amazon River, and known for its extensive

peacock bass Peacock bass or Brazilian tucunaré are large freshwater cichlids of the genus ''Cichla''. These are diurnal predatory fishes native to the Amazon and Orinoco basins, as well as rivers of the Guianas, in tropical South America. They are someti ...

population. It is a

blackwater river A blackwater river is a type of river with a slow-moving channel flowing through forested swamps or wetlands. As vegetation decays, tannins leach into the water, making a transparent, acidic water that is darkly stained, resembling black tea. ...

. The river flows through the Uatuma-Trombetas moist forests ecoregion. During the wet season starting in December, water levels can rise some 25 to 40 feet. Water levels have been strongly affected by the building of the controversial Balbina Dam on the river in the mid to late 1980s to generate electricity. The hydroelectric dam generates an average of 112.2 MW of electricity from the river system and floods a total of 2360 km² of rainforest around the Uatumã river. From the point where the river emerges from the dam it defines the east boundary of the Caverna do Maroaga Environmental Protection Area, established in 1990. The

Uatumã Biological Reserve Uatumã Biological Reserve ( pt, Reserva Biológica do Uatumã) is a Biological reserve around the river Uatumã in the state of Amazonas in Brazil. Location The Uatumã Biological Reserve is divided between the municipalities of Urucará (3 ...

established in 1990 is a

nature reserve A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, or features of geological or ...

around the river in the municipalities of

São Sebastião do Uatumã São Sebastião do Uatumã is a municipality located in the Brazilian state of Amazonas. Its population was 14,352 (2020) and its area is 10,741 km2. Conservation The municipality contains part of the Uatumã Biological Reserve, a strictly ...

and Itapiranga. The Uatumã Sustainable Development Reserve protects the lower part of the Uatumã River basin.

References

Rivers of Amazonas (Brazilian state) Tributaries of the Amazon River {{AmazonasBR-river-stub