Branco River
Branco River in Boa Vista city, Roraima state, Brazil. The Macuxi Bridge, 1.2 km (0.75 mi) long,[1] can be seen in the background.
The Branco River is a tributary of the Rio Negro (highlighted on map)
Native nameRio Branco (Portuguese)
Location
Country Brazil
Physical characteristics
Source 
 • locationconfluence of Takutu and Uraricoera, Roraima, Brazil
 • coordinates3°1′28.5276″N 60°29′14.8596″W / 3.024591000°N 60.487461000°W / 3.024591000; -60.487461000
 • elevation64 m (210 ft)
2nd source 
 • locationUraricoera, Parima Mountains
 • coordinates3°41′42.2484″N 64°12′36.018″W / 3.695069000°N 64.21000500°W / 3.695069000; -64.21000500
 • elevation1,240 m (4,070 ft)
3rd source 
 • locationTakutu, Guiana Shield
 • coordinates1°47′48.6492″N 60°1′38.2656″W / 1.796847000°N 60.027296000°W / 1.796847000; -60.027296000
 • elevation306 m (1,004 ft)
Mouth 
 • location
Rio Negro, Roraima, Brazil
 • coordinates
1°23′38″S 61°50′46″W / 1.39389°S 61.84611°W / -1.39389; -61.84611
 • elevation
12 m (39 ft)
Length560 km (350 mi)[2] to 775 km (482 mi)[3]
Basin size192,392.66 km2 (74,283.22 sq mi)[4]
Discharge 
 • locationConfluence of Rio Negro, Roraima
 • average(Period:1967-2010)5,400 m3/s (190,000 cu ft/s)[4]

(Period: 1980-2006)5,300 m3/s (190,000 cu ft/s)[6]

(Period: 1998-2022)6,469 m3/s (228,500 cu ft/s)[5]
 • minimum278 m3/s (9,800 cu ft/s)[5]
 • maximum28,697 m3/s (1,013,400 cu ft/s)[5]
Discharge 
 • locationCaracaraí (400 km upstream of mouth; Basin size: 124,980 km2 (48,260 sq mi)
 • average(Period: 1997/01/01-2015/12/31)

3,170.343 m3/s (111,959.6 cu ft/s)[7]

(Period: 1998-2022)3,615.65 m3/s (127,685 cu ft/s)[4]
 • minimum178 m3/s (6,300 cu ft/s) (1998/03/24)[4]
 • maximum15,735 m3/s (555,700 cu ft/s) (1976/07/10)[4]
Discharge 
 • locationBoa Vista (Basin size: 97,200 km2 (37,500 sq mi)
 • average(Period: 1967-2010)2,436.76 m3/s (86,053 cu ft/s)[4] (Period: 1998-2022)3,129.97 m3/s (110,534 cu ft/s)[4]
Basin features
Tributaries 
 • leftTakutu, Anauá, Itapará
 • rightUraricoera, Mucajai, Ajarani, Univini, Catrimani, Xeruini

The Branco River (Portuguese: Rio Branco; Engl: White River) is the principal affluent of the Rio Negro from the north.

Basin

The river drains the Guayanan Highlands moist forests ecoregion.[8] It is enriched by many streams from the Tepui highlands which separate Venezuela and Guyana from Brazil. Its two upper main tributaries are the Uraricoera and the Takutu.[9] The latter almost links its sources with those of the Essequibo; during floods headwaters of the Branco and those of the Essequibo are connected, allowing a level of exchange in the aquatic fauna (such as fish) between the two systems.[10]

The Branco flows nearly south, and finds its way into the Negro through several channels and a chain of lagoons similar to those of the latter river. It is 350 miles (560 km) long, up to its Uraricoera confluence. It has numerous islands, and, 235 miles (378 km) above its mouth, it is broken by a bad series of rapids.

Discharge

Average, minimum and maximum discharge of the Branco River at near mouth. Period from 1998 to 2022.[5]

Year Discharge (m3/s) Year Discharge (m3/s)
Min Mean Max Min Mean Max
1998 5,664 16,435 2011 454 5,008 16,815
1999 1,792 9,538 22,576 2012 2,135 8,381 17,944
2000 2,506 9,725 28,697 2013 1,377 6,493 13,229
2001 788 6,551 17,791 2014 1,117 6,384 15,489
2002 1,271 5,219 18,760 2015 772 3,983 10,416
2003 640 4,375 13,320 2016 435 4,316 11,677
2004 756 4,244 11,959 2017 2,258 7,437 16,449
2005 729 7,868 19,893 2018 777 6,653 17,912
2006 2,457 9,899 22,644 2019 625 5,205 15,859
2007 845 7,271 15,118 2020 1,567 7,216 16,564
2008 2,739 7,630 17,280 2021 1,712 8,828 23,180
2009 486 4,318 10,735 2022 1,810 9,087 23,631
2010 278 2,754 8,040 278 6,469 28,697

Water chemistry

As suggested by its name, the Branco (literally "white" in Portuguese) has whitish water that may appear almost milky due to the inorganic sediments it carries.[11] It is traditionally considered a whitewater river,[12][13] although the major seasonal fluctuations in its physico-chemical characteristics makes a classification difficult and some consider it clearwater.[14][15] Especially the river's upper parts at the headwaters are clear and flow through rocky country, leading to the suggestion that sediments mainly originate from the lower parts.[11] Furthermore, its chemistry and color may contradict each other compared to the traditional Amazonian river classifications.[14] The Branco River has pH 6–7 and low levels of dissolved organic carbon.[15]

Alfred Russel Wallace mentioned the coloration in "On the Rio Negro", a paper read at the 13 June 1853 meeting of the Royal Geographical Society, in which he said: "[The Rio Branco] is white to a remarkable degree, its waters being actually milky in appearance". Alexander von Humboldt attributed the color to the presence of silicates in the water, principally mica and talc.[16] There is a visible contrast with the waters of the Rio Negro at the confluence of the two rivers. The Rio Negro is a blackwater river with dark tea-colored acidic water (pH 3.5–4.5) that contains high levels of dissolved organic carbon.[15]

River capture

Until approximately 20,000 years ago the headwaters of the Branco River flowed not into the Amazon, but via the Takutu Graben in the Rupununi area of Guyana towards the Caribbean.[17] Currently in the rainy season much of the Rupununi area floods, with water draining both to the Amazon (via the Branco River) and the Essequibo River.[10]

Citations

Notes

  1. ^ UOL. Turismo em Boa Vista. Access on Feb 17 2012.
  2. ^ Ziesler, R.; Ardizzone, G.D. (1979). "Amazon River System". The Inland waters of Latin America. Food and Agriculture Organization of the United Nations. ISBN 92-5-000780-9. Archived from the original on 8 November 2014.
  3. ^ "Branco-River".
  4. ^ a b c d e f g "Amazon basin water resources observation service".
  5. ^ a b c d "River Discharge and Reservoir Storage Changes Using Satellite Microwave Radiometry".
  6. ^ Seyler, Patrick; Laurence Maurice-Bourgoin; Jean Loup Guyot. "Hydrological Control on the Temporal Variability of Trace Element Concentration in the Amazon River and its Main Tributaries". Geological Survey of Brazil (CPRM). Retrieved 24 July 2010.
  7. ^ Jamie, Towner (2019). "Assessing the performance of global hydrological models for capturing peak river flows in the Amazon basin" (PDF).
  8. ^ Sears, Robin, South America: Southern Venezuela, northern Brazil, western Guyana, and eastern Colombia (NT0124), WWF: World Wildlife Fund, retrieved 2017-04-01
  9. ^ "Map of the Branco or Parimé River and of the Caratirimani Uararicapará Majari, Tacutú and Mahú Rivers". World Digital Library. Retrieved 27 April 2013.
  10. ^ a b Quinn, J.A.; S.L. Woodward, eds. (2015). Earth's Landscape: An Encyclopedia of the World's Geographic Features. Vol. 1. Bloomsbury Academic. p. 142. ISBN 978-1-61069-445-2.
  11. ^ a b The Alfred Russel Wallace page: On the Rio Negro. Retrieved 10 October 2017.
  12. ^ Venticinque; Forsberg; Barthem; et al. (2016). "An explicit GIS-based river basin framework for aquatic ecosystem conservation in the Amazon". Earth Syst. Sci. Data. 8 (2): 651–661. Bibcode:2016ESSD....8..651V. doi:10.5194/essd-8-651-2016.
  13. ^ Val, A.L.; V.M.F. de Almeida-Val; D.J. Randall, eds. (2013). Fish Physiology: The Physiology of Tropical Fishes. p. 27. ISBN 978-0-12350-445-6.
  14. ^ a b Ríos-Villamizar, E.A.; M.T.F. Piedade; J.G. da Costa; J.M. Adeney; J. Junk (2013). "Chemistry of different Amazonian water types for river classification: A preliminary review".
  15. ^ a b c de Souza kodra, A.; M.N. Fernandes; W.L. Paxiúba Duncan (2014). "Effect of clearwater on osmoregulation of cururu ray, Potamotrygon sp. (Chondrichthes; Potamotrogonidae), an endemic species from blackwater river". Scientia Amazonia. 3 (1): 15–24.
  16. ^ "Alexander von Humboldt, Personal Narrative of Travels to the Equinoctial Regions of America During the Years 1799-1804, (chapter 25). Henry G. Bohn, London, 1853". Archived from the original on 2016-03-03. Retrieved 2015-05-13.
  17. ^ Cremon, É. H. (2016). Evolução quaternária do Rio Branco - norte da Amazônia - com base em dados orbitais e geológicos. Tese (Doutorado em Sensoriamento Remoto) - Instituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos.((cite book)): CS1 maint: location missing publisher (link)

References