The Branco River ( pt, Rio Branco; Engl: ''White River'') is the principal
affluent
Wealth is the abundance of valuable financial assets or physical possessions which can be converted into a form that can be used for transactions. This includes the core meaning as held in the originating Old English word , which is from an I ...
of the
Rio Negro from the north.
Basin
The river drains the
Guayanan Highlands moist forests
The Guayanan Highlands moist forests (NT0124) is an ecoregion in the south of Venezuela and the north of Brazil and in Guyana, Suriname, French Guiana. It is in the Amazon biome.
It encompasses an upland region with diverse fauna and flora, which ...
ecoregion.
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
The Uraricoera River (Uraricuera) is a river of Roraima state in northern Brazil. The confluence of the Uraricoera and Takutu Rivers forms the Branco River.
Basin
The river drains the Guayanan Highlands moist forests ecoregion.
Part of the river' ...
and the
Takutu.
The latter almost links its sources with those of the
Essequibo Essequibo is the largest traditional region of Guyana but not an administrative region of Guyana today. It may also refer to:
* Essequibo River, the largest river in Guyana
* Essequibo (colony), a former Dutch colony in what is now Guyana;
* Esseq ...
; 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.
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 long, up to its Uraricoera
confluence
In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...
. It has numerous
islands, and, 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.
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.
[The Alfred Russel Wallace page]
On the Rio Negro.
Retrieved 10 October 2017. It is traditionally considered a
whitewater river, although the major seasonal fluctuations in its physico-chemical characteristics makes a classification difficult and some consider it
clearwater Clearwater or Clear Water may refer to:
Places Canada
* Clear Water Academy, a private Catholic school located in Calgary, Alberta
* Clearwater (provincial electoral district), a former provincial electoral district in Alberta
* Clearwater, Briti ...
.
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.
[ Furthermore, its chemistry and color may contradict each other compared to the traditional Amazonian river classifications.][ The Branco River has pH 6–7 and low levels of dissolved organic carbon.][
]Alfred Russel Wallace
Alfred Russel Wallace (8 January 1823 – 7 November 1913) was a British naturalist, explorer, geographer, anthropologist, biologist and illustrator. He is best known for independently conceiving the theory of evolution through natural se ...
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.[
]
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.[
]
Citations
Notes
References
Encyclopædia Britannica Online.com: "Branco River"
. retrieved 19 September 2009.
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Rivers of Roraima
Tributaries of the Rio Negro (Amazon)
Boa Vista, Roraima
Guayana Highlands