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The Orinoco () is one of the longest
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of ...
s in
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
at . Its
drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
, sometimes known as the Orinoquia, covers , with 76.3 percent of it in
Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
and the remainder in
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the ...
. It is the fourth largest river in the world by
discharge Discharge may refer to Expel or let go * Discharge, the act of firing a gun * Discharge, or termination of employment, the end of an employee's duration with an employer * Military discharge, the release of a member of the armed forces from ser ...
volume of water. The Orinoco River and its tributaries are the major transportation system for eastern and interior Venezuela and the Llanos of Colombia. The environment and wildlife in the Orinoco's basin are extremely diverse.


Etymology

The river's name is derived from the Warao term for "a place to paddle", itself derived from the terms ''güiri'' (paddle) and ''noko'' (place) i.e. a navigable place.


History

The mouth of the Orinoco River at the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
was documented by
Christopher Columbus Christopher Columbus * lij, Cristoffa C(or)ombo * es, link=no, Cristóbal Colón * pt, Cristóvão Colombo * ca, Cristòfor (or ) * la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...
on 1 August 1498, during his third voyage. Its source at the Cerro Delgado–Chalbaud, in the Parima range, was not explored until 453 years later, in 1951. The source, near the Venezuelan–
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
ian border, at above sea level (), was explored in 1951 by a joint French-Venezuelan expedition. The Orinoco, as well as its tributaries in the eastern llanos such as the Apure and Meta, were explored in the 16th century by German expeditions under
Ambrosius Ehinger Ambrosius Ehinger, also (Ambrosio Alfínger in Spanish) Dalfinger, Thalfinger, (ca. 1500 in Thalfingen near Ulm – 31 May 1533 near Chinácota in modern-day Colombia) was a German conquistador and the first governor of the Welser concess ...
and his successors. In 1531, starting at the principal outlet in the delta, the Boca de Navios, Diego de Ordaz sailed up the river to the Meta.
Antonio de Berrio Antonio de Berrío ( Segovia, 1527 – Santo Tomé de Guayana, the current Ciudad Bolívar, in the state Bolívar, 1597), was a Spanish soldier, governor and explorer in Colonial America. Biography Antonio de Berrío began his military care ...
sailed down the Casanare to the Meta, and then down the Orinoco River and back to Coro. In 1595, after capturing de Berrio to obtain information while conducting an expedition to find the fabled city of El Dorado, the Englishman Sir Walter Raleigh sailed down the river, reaching the savanna country.
Alexander von Humboldt Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 17696 May 1859) was a German polymath, geographer, naturalist, explorer, and proponent of Romantic philosophy and science. He was the younger brother of the Prussian minister ...
explored the basin in 1800, reporting on the pink river dolphins. He published extensively on the river's flora and fauna. The sources of the Orinoco River, located at Cerro Carlos Delgado Chalbaud (2º19’05” N, 63º21’42” W), were discovered in 1951 by the French-Venezuelan expedition that went back and explored the Upper Orinoco course to the Sierra Parima near the border with Brasil, headed by Venezuelan army officer Frank Risquez Iribarren. The first bridge across the Orinoco River, the
Angostura Bridge Angostura Bridge is a suspension bridge that spans the Orinoco River at Ciudad Bolívar, Venezuela. The Spanish word Angostura means "narrows". Built in 1967 at a cost of US$35million, the bridge has a total length of 1,678.50 meters, a distance ...
at
Ciudad Bolívar Ciudad Bolívar (; Spanish for "Bolivar City"), formerly known as Angostura and St. Thomas de Guyana, is the capital of Venezuela's southeastern Bolívar State. It lies at the spot where the Orinoco River narrows to about in width, is the si ...
, Venezuela, was completed in 1967. In 1968, an expedition was set off by National Geographic and Hovercraft from Manaus (
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
) to Port of Spain (Trinidad). Aboard of a SR.N6 hoverwork the expedicionaries followed the Negro river upstream to where it is joined by the
Casiquiare canal The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...
in the border between Colombia and Venezuela. After following the Casiquiare to the Orinoco River they hovered thru perilous Rapids of Maipures and Atures. The Orinoco was then traversed down to its mouths in the Gulf of Paria and then to Port of Spain. The primary purpose of the expedition was filming for the BBC series ''
The World About Us ''The World About Us'' was a BBC Two television documentary series on natural history which ran from 3 December 1967 to 20 July 1986.''Encyclopedia of Television'' (2d ed.), ed. Horace Newcomb, p. 324, 620, 1363. The show was created by David At ...
'' episode "The Last Great Journey on Earth from Amazon to Orinoco by Hovercraft", which aired in 1970, and demonstrated the abilities of a hovercraft, thereby promoting sales of this British invention. The first powerline crossing of the Orinoco River was completed in 1981 for an 800kVTL single span of using two towers tall. In 1992, an overhead power line crossing for two 400kV-circuits was completed just west of Morocure (between the cities of
Ciudad Bolívar Ciudad Bolívar (; Spanish for "Bolivar City"), formerly known as Angostura and St. Thomas de Guyana, is the capital of Venezuela's southeastern Bolívar State. It lies at the spot where the Orinoco River narrows to about in width, is the si ...
and
Ciudad Guayana Ciudad Guayana () (in English Guayana City) is a city in Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco river, at the point where it is joined by its main tributary, the Caroní river. The Caroni cro ...
), north of the confluence of Routes1 and 19. It had three towers, and the two spans measured and , respectively. In 2006, a second bridge, known as the
Orinoquia Bridge The Second Orinoco crossing or Orinoquia Bridge is a combined road and railway bridge over the Orinoco River near Ciudad Guayana, Venezuela. It was inaugurated on November 13, 2006 and named ''Orinoquia'' Bridge. Prior to its construction, the on ...
, was completed near
Ciudad Guayana Ciudad Guayana () (in English Guayana City) is a city in Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco river, at the point where it is joined by its main tributary, the Caroní river. The Caroni cro ...
, Venezuela.


Geography

The course of the Orinoco forms a wide ellipsoidal arc, surrounding the
Guiana Shield The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a ...
; it is divided in four stretches of unequal length that very roughly correspond to the longitudinal zonation of a typical large river: * Upper Orinoco – long, from its headwaters to the Raudales de Guaharibos rapids, flows through mountainous landscape in a northwesterly direction * Middle Orinoco – long, divided into two sectors, the first of which ca. long has a general westward direction down to the confluence with the Atabapo and Guaviare rivers at
San Fernando de Atabapo San Fernando de Atabapo is a town in southern Venezuela on the border with Colombia. It was the capital city of the Amazonas state until the early 1900s. The population in 1997 was approximately 5,000. In the early twentieth century it was rul ...
; the second flows northward, for about , along the Venezuelan–Colombian border, flanked on both sides by the westernmost granitic upwellings of the Guiana Shield which impede the development of a flood plain, to the Atures rapids near the confluence with the Meta River at Puerto Carreño *Lower Orinoco – long with a well-developed alluvial plain, flows in a northeast direction, from Atures rapids down to Piacoa in front of Barrancas * Delta Amacuro – long that empties into the Gulf of Paría and the Atlantic Ocean, a very large delta, some and at its widest. At its mouth, the Orinoco River forms a wide delta that branches off into hundreds of rivers and waterways that flow through of swampy forests. In the rainy season, the Orinoco River can swell to a breadth of and a depth of . Most of the important Venezuelan rivers are tributaries of the Orinoco River, the largest being the Caroní, which joins it at
Puerto Ordaz Ciudad Guayana () (in English Guayana City) is a city in Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco river, at the point where it is joined by its main tributary, the Caroní river. The Caroni cros ...
, close to the Llovizna Falls. A peculiarity of the Orinoco river system is the
Casiquiare canal The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...
, which starts as an arm of the Orinoco, and finds its way to the Rio Negro, a tributary of the
Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...
, thus forming a 'natural canal' between Orinoco and Amazon. The stream gradient of the entire river is 0.05% (1,047 m over 2,250 km). Downstream of Raudales de Guaharibos the gradient is 0.01% (183/1,964), which is also the gradient from Ciudad Bolivar to the ocean (54/435).


Major rivers in the Orinoco Basin

* Apure: from Venezuela through the east into the Orinoco * Arauca: from Colombia to Venezuela east into the Orinoco * Atabapo: from the
Guiana Highlands The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...
of Venezuela north into the Orinoco * Caroní: from the Guiana Highlands of Venezuela north into the Orinoco *
Casiquiare canal The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...
: in SE Venezuela, a distributary from the Orinoco flowing west to the Negro River, a major affluent to the Amazon * Caura: from eastern Venezuela (Guiana Highlands) north into the Orinoco * Guaviare: from Colombia east into the Orinoco * Inírida: from Colombia southeast into the Guaviare. * Meta: from Colombia, border with Venezuela east into the Orinoco * Ventuari: from eastern Venezuela (the Guiana Highlands) southwest into the Orinoco * Vichada: from Colombia east into the Orinoco


Ecology

The
boto Boto is a Portuguese name given to several types of dolphins and river dolphins native to the Amazon and the Orinoco River tributaries. A few botos exist exclusively in fresh water, and these are often considered primitive dolphins. Classificatio ...
and the giant otter inhabit the Orinoco River system.WWF:
Orinoco River Basin, South America.
' Retrieved 24 May 2014
The
Orinoco crocodile The Orinoco crocodile (''Crocodylus intermedius'') is a critically endangered crocodile. Its population is very small, and they can only be found in the Orinoco river basin in Colombia and Venezuela. Extensively hunted for their skins in the 1 ...
is one of the rarest reptiles in the world. Its range in the wild is restricted to the middle and lower Orinoco River Basin. More than 1000 fish species have been recorded in the river basin and about 15% are
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
. Among the fish in the river are species found in
brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estua ...
or salt water in the Orinoco
estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...
, but also many restricted to fresh water. By far the largest orders are Characiformes and Siluriformes, which together account for more than 80% of the fresh water species.Hales, J., and P. Petry:
Orinoco Llanos
'. Orinoco Delta & Coastal Drainages. Retrieved 24 May 2014.
Some of the more famous are the black spot piranha and the cardinal tetra. The latter species, which is important in the aquarium industry, is also found in the Rio Negro, revealing the connection between this river and the Orinoco through the
Casiquiare canal The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...
. Because the Casiquiare includes both blackwater and clear- to whitewater sections, only relatively adaptable species are able to pass through it between the two river systems.


Economic activity

The river is navigable for most of its length, and dredging enables ocean ships to go as far as
Ciudad Bolívar Ciudad Bolívar (; Spanish for "Bolivar City"), formerly known as Angostura and St. Thomas de Guyana, is the capital of Venezuela's southeastern Bolívar State. It lies at the spot where the Orinoco River narrows to about in width, is the si ...
, at the confluence of the Caroní River, upstream. River steamers carry cargo as far as
Puerto Ayacucho Puerto Ayacucho () is the capital and largest city of Amazonas State in Venezuela. Puerto Ayacucho is located across the Orinoco River from the Colombian village of Casuarito. The city was founded to facilitate the transport of goods past th ...
and the Atures Rapids.


El Florero iron mine

In 1926, a Venezuelan mining inspector found one of the richest
iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the ...
deposits near the Orinoco delta, south of the city of San Felix on a mountain named ''El Florero''. Full-scale mining of the ore deposits began after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
, by a conglomerate of Venezuelan firms and US steel companies. At the start in the early 1950s, about 10,000 tons of ore-bearing soil was mined per day.


Tar sands

The Orinoco River deposits also contain extensive tar sands in the Orinoco oil belt, which may be a source of future oil production.


Eastern Venezuelan basin

Encompassing the states of Anzoategui- Guarico and Monagas states, the Interior Range forms the northern boundary and the
Guayana Shield The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a 1 ...
the southern boundary.Prieto, R., Valdes, G., 1992, El Furrial Oil Field, In Giant Oil and Gas Fields of the Decade, 1978–1988, AAPG Memoir 54, Halbouty, M.T., editor, Tulsa: American Association of Petroleum Geologists, Maturin forms the eastern subbasin and Guarico forms the western subbasin. The El Furrial oil field was discovered in 1978, producing from late Oligocene shallow marine
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...
s in an overthrusted foreland basin.


Recreation and sports

Since 1973, the Civil Association Nuestros Rios son Navegables organize the Internacional Rally ''Nuestros Rios son Navegables'', a motonautical round trip of over 1,200 kilometers through the Orinoco, Meta and Apure Rivers. Starting out from Ciudad Bolívar or San Fernando de Apure, is the longest fluvial rally in the world with the participation of worldwide competitors, more than 30 support boats, logistics teams, thousands of tourists and fans travel. The boats had an average speed of 120 miles per hour. Since 1988, the local government of
Ciudad Guayana Ciudad Guayana () (in English Guayana City) is a city in Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco river, at the point where it is joined by its main tributary, the Caroní river. The Caroni cro ...
has conducted a swim race in the rivers Orinoco and Caroní, with up to 1,000 competitors. Since 1991, the ''Paso a Nado Internacional de los Rios Orinoco–Caroní'' has been celebrated every year, on a Sunday close to 19 April. Worldwide, this swim-meet has grown in importance, and it has a large number of competitors. The 26th meet was held in 2016.


See also

*
Adaheli Adaheli was the personification of the sun in the Carib mythology of the Orinoco region of South America. This sun god is referred to in an origin story collected in the early 20th century by , a missionary in Suriname. In the story, Adaheli ...
, the Sun in the
mythology Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narra ...
of the Orinoco region * ''
Fishes of the Orinoco in the Wild ''Fishes of the Orinoco in the Wild'' is a book written by photographer, artist and aquatic explorer Ivan Mikolji from Caracas, Venezuela. about aquatic fishes found in the Venezuelan and Colombian Amazon rainforest. In the book, Mikolji docum ...
'' (2020) book * Orinoco Flow – the song uses the Orinoco and its environs as a theme for its lyrics


Notes


References

* Stark, James H. 1897. ''Stark's Guide-Book and History of Trinidad including Tobago, Granada, and St. Vincent; also a trip up the Orinoco and a description of the great Venezuelan Pitch Lake''. Boston, James H. Stark, publisher; London, Sampson Low, Marston & Company. (This book has an excellent description of a trip up the Orinoco as far as
Ciudad Bolívar Ciudad Bolívar (; Spanish for "Bolivar City"), formerly known as Angostura and St. Thomas de Guyana, is the capital of Venezuela's southeastern Bolívar State. It lies at the spot where the Orinoco River narrows to about in width, is the si ...
and a detailed description of the Venezuelan
Pitch Lake The Pitch Lake is the largest natural deposit of asphalt in the world, estimated to contain 10 million tons. It is located in La Brea in southwest Trinidad, within the Siparia Regional Corporation. The lake covers about 100 acres (0.405 squ ...
situated on the western side of the Gulf of Paria opposite.) * MacKee, E.D., Nordin, C.F. and D. Perez-Hernandez (1998). "The Waters and Sediments of the Rio Orinoco and its major Tributaries, Venezuela and Colombia." United States Geological Survey water-supply paper, /A-B. Washington: United States Government Printing Office. * Weibezahn, F.H., Haymara, A. and M.W. Lewis (1990). ''The Orinoco River as an ecosystem''. Caracas: Universidad Simon Bolivar. * Rawlins, C.B. (1999). ''The Orinoco River''. New York: Franklin Watts. * http://www.gutenberg.org/files/50506/50506-h/50506-h.htm


External links

* * (Transcription of book from 1902)
"Rios de Integracion ". Geurgescu, Paul. CAF. 2017
{{Authority control Rivers of Colombia Rivers of Venezuela Border rivers Colombia–Venezuela border International rivers of South America Orinoco basin Dredged rivers and waterways