Branco River

This article is about the river in Roraima, Brazil. For other rivers with the same name, see Branco River (disambiguation).

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 name	Rio Branco (Portuguese)
Location
Country	Brazil
Physical characteristics
Source
• location	confluence of Takutu and Uraricoera, Roraima, Brazil
• coordinates	3°1′28.5276″N60°29′14.8596″W / 3.024591000°N 60.487461000°W / 3.024591000; -60.487461000
• elevation	64 m (210 ft)
2nd source
• location	Uraricoera, Parima Mountains
• coordinates	3°41′42.2484″N64°12′36.018″W / 3.695069000°N 64.21000500°W / 3.695069000; -64.21000500
• elevation	1,240 m (4,070 ft)
3rd source
• location	Takutu, Guiana Shield
• coordinates	1°47′48.6492″N60°1′38.2656″W / 1.796847000°N 60.027296000°W / 1.796847000; -60.027296000
• elevation	306 m (1,004 ft)
Mouth
• location	Rio Negro, Roraima, Brazil
• coordinates	1°23′38″S61°50′46″W / 1.39389°S 61.84611°W / -1.39389; -61.84611
• elevation	12 m (39 ft)
Length	560 km (350 mi) [2] to 775 km (482 mi) [3]
Basin size	192,392.66 km2 (74,283.22 sq mi) [4]
Discharge
• location	Confluence 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) [5] (Period: 1998-2022)6,469 m3/s (228,500 cu ft/s) [6]
• minimum	278 m3/s (9,800 cu ft/s) [6]
• maximum	28,697 m3/s (1,013,400 cu ft/s) [6]
Discharge
• location	Caracaraí (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]
• minimum	178 m3/s (6,300 cu ft/s) (1998/03/24) [4]
• maximum	15,735 m3/s (555,700 cu ft/s) (1976/07/10) [4]
Discharge
• location	Boa 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
• left	Takutu, Anauá, Itapará
• right	Uraricoera, 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]

Gaiola Anacorda, Branco River, Acre River, 1912

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. ^[6]

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. Archived 2016-03-03 at the Wayback Machine 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". Archived from the original on 2023-02-17. Retrieved 2023-03-10.
4. "Amazon basin water resources observation service". Archived from the original on 2023-09-08. Retrieved 2023-03-10.
5. 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). Archived from the original on 21 July 2011. Retrieved 24 July 2010.
6. "River Discharge and Reservoir Storage Changes Using Satellite Microwave Radiometry". Archived from the original on 2023-03-10. Retrieved 2023-03-10.
7. Jamie, Towner (2019). "Assessing the performance of global hydrological models for capturing peak river flows in the Amazon basin" (PDF). Archived (PDF) from the original on 2023-10-14. Retrieved 2023-03-10.
8. Sears, Robin, South America: Southern Venezuela, northern Brazil, western Guyana, and eastern Colombia (NT0124), WWF: World Wildlife Fund, archived from the original on 2020-09-22, 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. Archived from the original on 14 December 2013. Retrieved 27 April 2013.
10. 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. The Alfred Russel Wallace page: On the Rio Negro. Archived 2015-06-02 at the Wayback Machine 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. 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". Archived from the original on 2021-02-14. Retrieved 2017-12-11.
15. 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.

References

• Encyclopædia Britannica Online.com: "Branco River" . retrieved 19 September 2009.