TheTapajós (Portuguese:Rio Tapajós[ˈʁi.utɐpɐˈʒɔs]) is a river inBrazil. It runs through theAmazon Rainforest and is a major tributary of theAmazon River. When combined with theJuruena River, the Tapajós is approximately 2,080 km (1,290 mi) long.^[2] It is one of the largestclearwater rivers,^[10] accounting for about 6% of the water in theAmazon basin.^[11]

Tapajós River
The city ofItaituba on the banks of the Tapajós River
Map of the Amazon Basin with the Tapajós River highlighted
Location
Country	Brazil
Physical characteristics
Source
• location	Juruena–Teles Pires junction, Brazil
• coordinates	7°20′15″S58°8′35″W / 7.33750°S 58.14306°W /-7.33750; -58.14306
• elevation	95 m (312 ft)[1]
2nd source	Teles Pires
• location	Serra Azul,Mato Grosso
• coordinates	14°52′9.7608″S54°38′52.8468″W / 14.869378000°S 54.648013000°W /-14.869378000; -54.648013000
• elevation	800 m (2,600 ft)[1]
3rd source	Juruena
• location	Parecis Plateau,Mato Grosso
• coordinates	14°43′6.0168″S59°9′45.7848″W / 14.718338000°S 59.162718000°W /-14.718338000; -59.162718000
• elevation	700 m (2,300 ft)[1]
Mouth	Amazon
• location	Santarém,Pará State,Brazil
• coordinates	2°24′30″S54°44′12″W / 2.40833°S 54.73667°W /-2.40833; -54.73667
• elevation	1.4 m (4 ft 7 in)[1]
Length	840 km (520 mi)[2](825 km (513 mi)[1]–843 km (524 mi)[3])
Basin size	494,253.9 km2 (190,832.5 sq mi)[4]
Discharge
• location	Santarém,Pará State,Brazil (near mouth)
• average	(Period: 1985–2018)12,800 m3/s (450,000 cu ft/s)[5](Period: 1973–1990)13,540 m3/s (478,000 cu ft/s)[6]
• minimum	2,500 m3/s (88,000 cu ft/s)4,000 m3/s (140,000 cu ft/s)
• maximum	28,000 m3/s (990,000 cu ft/s)30,000 m3/s (1,100,000 cu ft/s)
Discharge
• location	Itaituba (Basin size: 460,101.1 km2 (177,646.0 sq mi)[4]
• average	(1985–2012)12,259 m3/s (432,900 cu ft/s)[7]
• maximum	34,233 m3/s (1,208,900 cu ft/s)[7]
Discharge
• location	São Luiz do Tapajós (420 km upstream of mouth; Basin size: 455,891.2 km2 (176,020.6 sq mi)[4]
• average	(Period: 1931–2012)12,998.3 m3/s (459,030 cu ft/s)[3]
• minimum	3,475 m3/s (122,700 cu ft/s)(1963/10)[3]
• maximum	39,277 m3/s (1,387,100 cu ft/s)(1940/03)[3]
Discharge
• location	Jatobá (Basin size: 387,378 km2 (149,567 sq mi)
• average	(Period: 1931–2013)10,814.2 m3/s (381,900 cu ft/s)[3](Period: 1970–1996)10,795 m3/s (381,200 cu ft/s)[8]
• minimum	3,430 m3/s (121,000 cu ft/s)(1931/09)[3]
• maximum	31,623 m3/s (1,116,800 cu ft/s)(1940/02)[3]
Discharge
• location	Barra de São Manuel (Basin size: 333,767.7 km2 (128,868.4 sq mi)[4]
• average	(Period of data: 1970–1996)8,339 m3/s (294,500 cu ft/s)[8](Period: 1971–2000)8,419.3 m3/s (297,320 cu ft/s)[4]
• minimum	2,148 m3/s (75,900 cu ft/s)(Year: 2002)[9]
• maximum	22,612 m3/s (798,500 cu ft/s)(Year: 1979)[9]
Basin features
Progression	Amazon →Atlantic Ocean
River system	Amazon
Tributaries
• left	Juruena,Arapiuns
• right	Teles Pires,Cururu,Das Tropas,Crepori,Jamanxim

For most of its length the Tapajós runs throughPará State, but the upper (southern) part forms the border between Pará andAmazonas State. Thesource is at the Juruena–Teles Pires river junction.^[2] The Tapajós River basin accounts for 6% of the water in theAmazon Basin, making it the fifth largest in the system.^[12]

From the lowerArinos River (a tributary of Juruena) to theMaranhão Grande falls are a more or less continuous series of formidable cataracts and rapids; but from the Maranhão Grande to the mouth of Tapajós, about 188 mi (303 km), the river can be navigated by large vessels.^[13]

For its last 100 mi (160 km) it is between 4 and 9 mi (6.4 and 14.5 km) wide and much of it very deep. The valley of the Tapajós is bordered on both sides by bluffs. They are from 300 to 400 ft (91 to 122 m) high along the lower river; but a few miles aboveSantarém, they retire from the eastern side and do not approach the Amazon floodplain until some miles below Santarém.^{[citation needed]}

The eastern border ofAmazônia National Park is formed by the TapajósRiver. FromItaituba and southwest a part of the Parque Nacional do Jacaré Branco e Azulado and the follows the river, while a part ofParque Nacional do Mico Verde de Olhos Azuis runs parallel to the river fromSantarém and south.^{[citation needed]}

The South Americanpole of inaccessibility is located close to the sources of Tapajós's tributaries, nearUtiariti.^{[citation needed]}

The Tapajós is named after theTapajós people, an extinct group ofindigenous people fromSantarém.^{[citation needed]}

The Tapajós is one of three majorclearwater rivers in the Amazon Basin (the others areXingu andTocantins; the latter arguably outside the Amazon).^[10][15] Clearwater rivers share the lowconductivity and relatively low levels ofdissolved solids withblackwater rivers, but differ from these in having water that at most only is somewhat acidic (typicalpH ~6.5)^[10] and very clear with a greenish colour.^[15] Although most of the tributaries in the Tapajós basin also are clearwater, there are exceptions, including the blackwater Braço Norte River (southeasternSerra do Cachimbo region).^[16] About 325 fish species are known from the Tapajós River basin, including 65endemics.^[17] Many of these have only been discovered within the last decade, and a conservative estimate suggests more than 500 fish species eventually will be recognized in the river basin.^[17]

The fish, along with many other endemic species of flora and fauna are threatened by theTapajós hydroelectric complex dams that are planned on the river.^[17] The largest of those projects is theSão Luiz do Tapajós Dam, whose environmental licensing process has been suspended – not yet cancelled – byIBAMA due to its expected impacts on indigenous and river communities.^[18]It would flood a part of the area of theSawré Muybu Indigenous Territory.Another is the planned 2,338 MWJatobá Hydroelectric Power Plant.^[19]A third dam, the controversialChacorão Dam, would flood a large area of theMunduruku Indigenous Territory.^[20]

The dams are part of a plan to convert the Tapajos into a waterway for barges to take soybeans fromMato Grosso to the Amazon River ports.A continuous chain of dams, with locks, would eliminate today's rapids and waterfalls.^[20]TheWashington Post has referred to this issue as the next battle over saving the Amazon as a result of its controversy involving Indigenous communities, the Brazilian government, large multinationals and international environmental organizations.^[21]

The river is the sixth title of the albumAguas da Amazonia.^{[citation needed]}