Tocantins River
| Tocantins River Pyti ( Parkatêjê)[1]: 59 | |
|---|---|
 Tocantins River and Fernando Henrique Cardoso bridge | |
 Map of the Araguaia/Tocantins Watershed | |
| Native name | Rio Tocantins (Portuguese) |
| Location | |
| Country | Brazil |
| Physical characteristics | |
| Source | Serra da Mesa Reservoir |
| • location | Minaçu, Goiás |
| • coordinates | 13°50′03″S 48°18′16″W / 13.83417°S 48.30444°W |
| • elevation | 443 m (1,453 ft) |
| Mouth | Marajó Bay |
• location | Igarapé-Miri, Pará |
• coordinates | 1°45′S 49°10′W / 1.750°S 49.167°W |
• elevation | 0 m (0 ft) |
| Length | 2,640 km (1,640 mi) |
| Basin size | 764,183 km2 (295,053 sq mi) |
| Discharge | |
| • location | mouth |
| • average | 11,796 m3/s (416,600 cu ft/s) |
| Basin features | |
| River system | Tocantins basin |
| Tributaries | |
| • left | Paranã, Sono River |
| • right | Araguaia River, Itacaiúnas River |
The Tocantins River (Portuguese: Rio Tocantins Portuguese pronunciation: [ˈʁi.u tokɐ̃ˈtʃĩs, tu-], Parkatêjê: Pyti [pɨˈti])[1]: 59 is a river in Brazil, the central fluvial artery of the country. In the Tupi language, its name means "toucan's beak" (Tukã for "toucan" and Ti for "beak"). It runs from south to north for about 2,450 km. It is not really a branch of the Amazon River, since its waters flow into the Atlantic Ocean alongside those of the Amazon. It flows through four Brazilian states (Goiás, Tocantins, Maranhão, and Pará) and gives its name to one of Brazil's newest states, formed in 1988 from what was until then the northern portion of Goiás.
The Tocantins is one of the largest clearwater rivers in South America.[2]
Course
It rises in the mountainous district known as the Pireneus, west of the Federal District, but its western tributary, the Araguaia River, has its extreme southern headwaters on the slopes of the Serra dos Caiapós. The Araguaia flows 1,670 km before its confluence with the Tocantins, to which it is almost equal in volume. Besides its main tributary, the Rio das Mortes, the Araguaia has twenty smaller branches, offering many miles of canoe navigation. In finding its way to the lowlands, it breaks frequently into waterfalls and rapids, or winds violently through rocky gorges, until, at a point about 160 km above its junction with the Tocantins, it saws its way across a rocky dyke for 20 km in roaring cataracts.[citation needed]
Two other tributaries, called the Maranhão and Paranatinga, collect an immense volume of water from the highlands which surround them, especially on the south and south-east. Between the latter and the confluence with the Araguaia, the Tocantins is occasionally obstructed by rocky barriers which cross it almost at a right angle.[citation needed]
Fauna
The Tocantins basin (which include the Araguaia River) is the home of several large aquatic mammals such as Amazonian manatee, Araguaian river dolphin and tucuxi, and larger reptiles such as black caiman, spectacled caiman and yellow-spotted river turtle.[3]
The Tocantins River Basin has a high
The
In its lower reaches, the Tocantins separates the Tocantins–Araguaia–Maranhão moist forests ecoregion to the east from the Xingu–Tocantins–Araguaia moist forests ecoregion to the west. It acts as a barrier that prevents dispersal of flora and fauna between these ecoregions.[9]
Dams
Downstream from the Araguaia confluence, in the state of Pará, the river used to have many cataracts and rapids, but they were flooded in the early 1980s by the artificial lake created by the
In total there are seven dams on the river (Serra da Mesa dam, Cana Brava dam, São Salvador dam, Peixe Angical dam, Luiz Eduardo Magalhães (Lajeado) dam, Estreito dam, and Tucuruí dam), of which the largest are the Tucuruí and the Serra da Mesa dam.[3]
Geology
The flat, broad valleys, composed of sand and clay, of both the Tocantins and its Araguaia branch are overlooked by steep bluffs. They are the margins of the great sandstone plateaus, from 300 to 600 metres (980 to 1,970 ft) elevation above sea-level, through which the rivers have eroded their deep beds. Around the estuary of the Tocantins the great plateau has disappeared, to give place to a part of the forest-covered, half submerged alluvial plain, which extends far to the north-east and west. The Pará River, generally called one of the mouths of the Amazon, is only the lower reach of the Tocantins. If any portion of the waters of the Amazon runs round the southern side of the large island of Marajó into the river Para, it is only through tortuous, natural canals, which are in no sense outflow channels of the Amazon.[citation needed]
Discharge
The Tocantins River records a mean discharge rate of 13,598 m3/s and a specific discharge rate of 14.4 L/s/km2. The sub-basins have the following specific discharge rates: Tocantins (11 L/s/km²), Araguaia (16 L/s/km²), Pará (17 L/s/km²) and Guamá (21 L/s/km²).[citation needed]
References
- ^ ISBN 978-85-910871-4-3.)
{{cite book}}: CS1 maint: location missing publisher (link - ^ Perez, M.S. "Where the Xingu Bends and Will Soon Break". American Scientist. Retrieved 1 October 2017.
- ^ a b c d e f Provete, D.B. (2013). Tocantins River. 1237-1239
- ^ a b c Hales, J., and P. Petry: Tocantins - Araguaia. Freshwater Ecoregions of the World. Retrieved 26 May 2014
- ^ Garavello, J.C.; Garavello, J.P.; and Oliveira, A.K. (2010). Ichthyofauna, fish supply and fishermen activities on the mid-Tocantins River, Maranhão State, Brazil. Braz. J. Biol., vol. 70(3): 575-585
- ^ Lambert de Brito Ribeiro, M. C.; Petrere Junior, M.; and Juras, A. A. (2006). "Ecological integrity and fisheries ecology of the Araguaia—Tocantins River Basin, Brazil." Regulated Rivers: Research & Management, vol. 11(3-4): 325–350
- ^ ISBN 978-1402000768
- ^ Caserta Tencatt; L. F.; and M. Elina Bichuette (2017). Aspidoras mephisto, new species: The first troglobitic Callichthyidae (Teleostei: Siluriformes) from South America. PLoS ONE 12(3): e0171309.
- ^ Sears, Robin, South America: Eastern extreme of the Amazon basin in Brazil (NT0170), WWF: World Wildlife Fund, retrieved 2017-03-25
External links
| International | |
|---|---|
| National | |
| Other | |
