Orinoco river

The Orinoco River is one of the most important rivers in South America (besides the Amazon River) that originates and flows mostly through Venezuela and partly through Colombia. It is the fourth longest South American river —2,800 km if the Orinoco-Guaviare system is considered and 2,140 km alone— and, with an average flow of about 33,000 m³/s, it is the third largest river in the world, after the Amazon and of the Congo. Its basin has an area of almost 989,000 km², of which 65% are in Venezuelan territory and the remaining 35% in Colombian territory.

The name of the river comes from the Otomacan Orinucu.

History

Map of Lower Orinoco (1897)

Small Caño, Orinoco River, Amazon State.

Orinoco River between Caicara and Cabruta.

Although the mouth of the Orinoco in the Atlantic Ocean was documented by Christopher Columbus on August 1, 1498, during his third voyage, its source on Cerro Delgado Chalbaud, was only first explored by non-indigenous people in 1951, 453 years later. The source, located on the border between Venezuela and Brazil, at 1047 m altitude (02°19′05″N 63°21′42″W / 2.31806, -63.36167), was explored in 1951 by a joint Franco-Venezuelan team.

The Spanish explorer Diego de Ordás was the first European to cross the Orinoco, between June and August 1531, from its delta to its confluence with the Meta.

The Orinoco delta and its tributaries in the eastern plains, such as the Apure and Meta, were explored in the 16th century by German expeditions led by Ambrosius Ehinger and his successors. In 1531, Diego de Ordaz, starting from the main current in the delta, the Boca de Navíos, ascended the river to its confluence with the Meta. Antonio de Berrío sailed down the Casanare until reaching the Meta, which also descended until it then reached the Orinoco, which continued back to Santa Ana de Coro.

Alexander von Humboldt explored the basin in the 1800s, reporting on pink river dolphins, and publishing extensively on its flora and fauna.

Geography

The Orinoco in its confluence with the River Caroní (left part).

The Orinoco in the state of Amazonas.

The Orinoco River is born in Venezuela, in the Amazonas State, and from the confluence of the Guaviare it forms the border with Colombia until the confluence with the Meta, from which it separates the Venezuelan states of Apure, Guárico, Anzoátegui State and Monagas, on the left, of the Bolívar State, on the right. When the delta begins, it opens up forming the Delta Amacuro State, located between Monagas to the left of the Mánamo channel and, on the right side, the Bolívar State and Guyana, although in this last sector, it would only be valid if the Amacuro River is considered (which is the one that forms the border) as a tributary of the Orinoco.

The course of the Orinoco draws a wide ellipsoidal arc that surrounds the Guiana Shield, first to the northwest, then to the west —until the triple confluence with the Guaviare and the Atabapo—, then to the north —marking at its most important point of fauna and flora, the Venezuelan border with Colombia until the confluence with the Meta—and finally in an east-northeast direction to the Atlantic Ocean—from the confluence with the Apure. Its course can be considered divided into four sections of unequal length that approximately correspond to the typical longitudinal zoning of a large river:

• Alto OrinocoOf 242 km in length, a section that runs from its headboard in Venezuela—in the hill Delgado Chalbaud, in the Parima mountain range, located south of the Amazon state—to the rapids of Raudales de Guaharibos in which it flows through a mountainous landscape in the northwest direction;

• Middle OrinocoOf 750 km long, a section divided in turn into two sectors: the first of them, of some 480 kmin which the river runs in general west to the confluence with the Atabapo and Guaviare rivers in San Fernando de Atabapo; the second, of about 270 km, in which it flows north by the Venezuelan-Colombian border, flanked on both sides by the most western granitic outcrops of the Guayanés Escudo, which prevents the development of a river

• Under OrinocoOf 959 km long, a stretch with a well-developed alluvial plain in which the Orinoco flows northeast, from the rapids of Atures to Piacoa, in front of the city of Barrancas;

• Delta AmacuroOf 200 km long, in which the river flows into the Gulf of Paria and the Atlantic forming a large delta branched into hundreds of branches, called pipes, covering a wet jungle area and pantanous forests of between 22 500-41 000 km2 and 370 km at its widest point. In the rainy season, the Orinoco can increase to a width of 22 km and a depth of 100 m. The region of alluvial plains to the north of the river, whose altitude does not exceed 100 m. n. m., is flooded in that time of rain, leaving the rest of the year lands whose vegetation is of intertropical grasslands of savannah.

The Orinoco is navigable in practically its entire length, allowing ocean-going ship traffic to Ciudad Orinoco and Ciudad Bolívar, where the Angostura bridge is located, 435 km from the mouth.

Most of the important Venezuelan rivers are tributaries of the Orinoco, the largest being the Caroní River, which joins it in Ciudad Guayana, near the La Llovizna waterfall. The Guaviare River is one of the main tributaries of the Orinoco, and the southernmost. If the source of the Guaviare were taken as the source of the Orinoco, its official length would be 2,800 km.

A peculiarity of the Orinoco fluvial system is the channel or Casiquiare river, which begins as an arm of the Orinoco, and finds its way to the Negro river, a tributary of the Amazon, thus forming a natural channel between the Orinoco and Amazon basins.

Orinoco Delta

The Orinoco delta, formed at the mouth of the river, is one of the largest in the world. Its extension made the first Spanish explorers think that it was a sea. It is located in the Delta Amacuro state, in eastern Venezuela. It is considered a place of great landscape richness due to the great variety of flora and fauna that it houses. Inspired by the thought of Heródoto, Domingo Ordaz from Delta says that the delta is a "present of the Orinoco", referring to the group of islands and pipes located in the area near the mouth. Considering the delta as a present of the Orinoco is not only useful metaphorically, but is reflected in reality, since most of the islands that make it up are the product of the constant accumulation of materials that the Orinoco has dragged through its millennial existence, with the contribution of its tributaries and to the extent that the sea withdrew from the foothills of the Sierra Imataca, to where it had penetrated, forming an immense gulf with an mouth of approximately 350 km. Not all of its islands are the product of sediment accumulation, but they were also formed by the accumulation of mud from eruptions of mud volcanoes, such as the Cedral hill located in Capure and the Cotorra and Plata islands, located to the north of Pedernales. The formation of the delta goes back in time to the Tertiary Era, thousands of years before it constituted a geographical space covered by the sea, but due to the action of the marine currents, the withdrawal of the sea waters occurred, producing the delta. The climate is characterized by presenting an average temperature of 26.7 °C, the average maximum is 32.3 °C and the average minimum is 23 °C. The rainfall reaches from 900 to 2500 mm, between minimum and maximum respectively.

The trade winds from the northeast and southeast, when they come into contact with delta lands, produce the east-west wind that advances through the Orinoco riverbed. During the flood, the presence of the so-called Barinese wind is observed, which moves following the same direction as the Orinoco. In the season of less rainfall, the so-called "northern" winds act in the area. Due to the influence of the tides that occur in the Atlantic, the flow of water from the Orinoco River and the delta pipes rises and falls. The action by which the tide enters and changes the direction of the river and its network of pipes is called flow and the exit or descent of the water allowing the current of the river and pipes to take their normal direction is called ebb. When the flow reaches its maximum level, it makes it possible for the salt water to move into the delta through its pipes, which overflow and flood the adjacent lands, facilitating the formation of large mangroves, located in the areas near the Atlantic coast. The tides constituted a valuable resource for navigation through the Orinoco and its pipes, at the time when there were no motors. They are also used to catch fish in fluvial arteries of short length and low flow, for this the mouths of these are covered and at low tide fishing is facilitated. It performs an important cleaning function, during its ebb, where the houses are built on wooden piles, in the aboriginal ranches and populated centers that are located in the areas of the pipes.

The delta is mentioned in the original title of the novel Robinson Crusoe (Daniel Defoe, 1719), as it appears on the cover of its first edition is The life and incredible adventures of Robinson Crusoe, of York, a sailor, who lived twenty-eight years completely alone on an uninhabited island off the Coast of America, near the Mouth of the Great Orinoco River; having been washed ashore after a shipwreck, in which all the men died except him. With an explanation of how he ended up being uncharacteristically freed by pirates. Written by himself.

Tributaries

The main tributaries of the Orinoco are, in a downstream direction:

• in Venezuelan territory:

• Casiquiare river (326 km), which is not an tributary but the opposite, an effluent, on the left margin, which is heading west to reach the river Guainía that takes the name of the river Negro (afluent of the Amazon) from this confluence;
• Ventuari river (520 km), on the right, arriving from eastern Venezuela (Guayana Highlands) in the north direction;
• Atabapo river, on the left, coming from the Guayanese shield after forming the border Colombia-Venezuela

• In Colombian territory:
• Guaviare river (1550 km), on the left, arriving from the east of Colombia and having as main tributary to the long river Inírida (1300 km);

• Vichada River (Vichada River)580 km), on the left, arriving from the east of Colombia;
• River Tomo (560 km), on the left, arriving from the east of Colombia;
• Target river1050 km), on the left, arriving from the east of Colombia;

• Border territory

• Cinaruco river (480 km);
• Capanaparo River650 km), on the left, arriving from Colombia;
• Arauca river (1050 km), on the left, arriving from Colombia;
• river Apure (1000 km), on the left, coming from the east;
• Guárico River525 km);
• Caura River723 km), on the right coming from the Guayanese shield in the north direction;
• River Caroní (Caroní River)700 km), on the right coming from the Guayanese shield of northern Venezuela and which has as a subfluent to the Carrao River, where is the highest waterfall in the world, the Angel Fall.

Physical geography

View of Mariusa National Park.

The Orinoco river basin synthesizes the three great forms of relief that exist in nature: ancient massifs and shields on the one hand, recently raised mountain ranges (that is, from the Tertiary) on the other, and tectonic depressions and basins or accumulation plains, third. Each of these forms of relief has its own characteristics, but also its similarities with similar natural regions in other parts of the world. For any country, and even more if we are in the intertropical zone, it represents a great ecological and economic advantage to have these three forms of relief represented in its territory and in all of America, only Canada and the United States as well as Venezuela and Colombia, which In its territory it has a reduced part of the Guyanese shield, they present a similar geological arrangement. If we define the Orinoco basin as a natural region, we must begin by establishing the geographical characteristics that define it, such as extension, relief, climate, hydrography, vegetation, soils, and mineral resources, topics that are summarized below.

Extension

The Orinoco basin has an area of almost 989,000 km², of which 643,480 km² (65%) are in Venezuelan territory, and the remaining 35% is in Colombian territory, in the Llanos and the eastern slope of the Cordillera Oriental, a section of the great Cordillera de los Andes. This Colombian region receives the name of Orinoquía. Of the part located in Venezuela, slightly more than half extends from the Venezuelan Andes and the Coastal Cordillera to the northwestern bank of the Orinoco River itself (the left bank), forming most of the Venezuelan Llanos and the Delta of the Orinoco. And the southern part of the basin collects most of the water that comes from the Venezuelan Guayana.

Relief

The Angel Fall.

Union of the waters of the Orinoco with the Caroní.

From the source of the Orinoco on Cerro Delgado Chalbaud 1047 m s. no. m. Up to its mouth, the Orinoco describes a great arc and its basin extends like a fan, which is why the northwestern part of the basin is somewhat more extensive than the southeastern part. As already indicated, the two subregions of the basin have quite different characters, due to differences in their geological constitution. The maximum height of the basin is found in the Sierra Nevada del Cocuy, in Colombia (more than 5,000 meters above sea level), which is part of the Eastern Cordillera of the Andes of Colombia.

The northwest edge of the basin would be formed by the Colombian-Venezuelan Andean slopes and the southern slopes of other mountainous reliefs of northern Venezuela, while the southern edge of the basin would be marked, for the most part, by the divide of waters between the Orinoco and the Amazon, which is located on the Guiana massif. Between both borders the Venezuelan Guayana extends on the right bank of the Orinoco and the Llanos, both Colombian and Venezuelan, on the left bank. As we can see, the Orinoco River itself clearly marks the natural limit between these two regions; It could be said that the Orinoco is one of the most notable natural borders that exist in the world, although this fact has a simple explanation: the rivers of the plains have a slight slope and have been building for millions of years an accumulation plain with the sediments that they carry from the mountain ranges where they are born. And it is these sediments that push the course of the Orinoco against the Guyanese shield itself.

Venezuelan Guayana constitutes, unlike the Llanos, a surface of erosion. From the combination of these two forces that modify the relief, one constructive, sedimentation and the other destructive, erosion, arises the current situation in which the river marks the limit between the two regions. This limit presents some exceptions since, in some stretches, rounded hills of granite origin (and which, therefore, are Guyanese reliefs) can be seen on the left bank of the Orinoco, that is, on the edge of the Llanos. And in front of Ciudad Bolívar, one of these rounded granite hills in the very center of the river can be seen, especially in times of low water: it is the Piedra del Medio, where you can see the different levels usually reached by the waters. of the river, expressed in the different coloration of the granite. The sandstones of the Venezuelan Guayana (from the Roraima Formation) have been transformed into sand by erosion that, although it was never very intense due to the extraordinary resistance of the rocks, has been very long-lasting (more than 1000 million years). Therefore, the sedimentary cover has been transforming into an inverted relief that forms the tepuis. The sands from this erosive process have been deposited on the left bank of the river, especially in the Llanos Bajos of Apure state, between the Meta and Apure rivers. They were not deposited on the right bank because the relief is higher there.

In turn, these sands have come to create a unique ecosystem in the world: an extensive field of dunes (occupies about 30,000 km²) that has the particularity that it is not a desert climate but a climate of savannah in a landscape of natural pastures that alternate with some gallery forests, mighty rivers and dunes of more than 100 km in length and up to 20 m in height. Some of these dunes are used by the plains to establish cheese factories, with which, in addition to processing part of the milk, a group of cattle is prepared to go in front of the herd (which in the plains is called the godmother of the flock). They also serve as shelter for livestock from flooding. Thus, this curious and picturesque ecosystem is the result of wind modeling in a savannah climate. It is not treated, as indicated in the Atlas of Venezuela. A spatial image (also known as the PDVSA Atlas), of an ecosystem of «paleodunes» formed in an environment with a much drier climate than today, but of a mechanism of formation of dunes that only works during the dry season since, when the level of the Orinoco waters drops due to the low water levels of the rivers, especially those that come from the Llanos, some extensive beaches of very fine sand remain, that the trade winds soon move to the southeast, forming what is now the Santos Luzardo National Park, a name taken from one of the main characters in the famous novel Doña Bárbara, by Rómulo Gallegos.

Deltaic System natural region

View of Cascadas, in Canaima National Park.

The Sistema Deltaico natural region is one of the nine natural regions of Venezuela. This has an extension of 32,000 km² that is located to the east of Venezuela between the low Llanos de Monagas, the Guiana Massif and the Atlantic Ocean. It is a region that is in the process of consolidation of low height and little unevenness, for which it is frequently flooded and invaded by the tides in the vicinity of the sea, with an abundance of lagoons, swamps, numerous islands and innumerable arms and pipes or channels. It constitutes the delta at the mouth of the Orinoco River and from there comes its name.

Wildlife

The Orinoco is the habitat of a large number of species. The current state of knowledge of its flora and fauna (insects, fish, herpetos, birds and mammals). The most outstanding species are classified as follows Mammals, the boto or Pink dolphin (Inia geoffrensis), Jaguar (Panthera onca), Capybara (Hydrochoerus hydrochaeris), Palmero Bear (Myrmecophaga tridactyla), Otter (Lutrinae), in the Reptiles The Orinoco Crocodile (Crocodylus intermedius), the Anaconda (Eunectes), Iguana (Iguana iguana), Lizards (Teiidae), Stifles (Caiman crocodilus), in Amphibians the Morrocoy or Red-legged Tortoise (Chelonoidis carbonaria), Motelo Tortoise or yellow legs (Chelonoidis denticulata), Loggerhead Turtle (Peltocephalus dumerilianus),(Podocnemis erythrocephala) Frogs, Toads among others, fish such as the Caribbean piranha (Pygocentrus cariba), Surapire (Myleus schomburgkii) Black Cachama (Colossoma macropomum), Catfish Dorad or (Brachyplatystoma rousseauxi). This region, due to oil exploitation or the cultivation of the African palm, has caused severe droughts, of which the Department of (Casanare) of the (Republic of Colombia) stands out.) in the municipality of (Paz de Ariporo) in 2014.

The hydrological phenomenon of «bore»

The word "bore" designates a rapid and noisy wave of the waters in a river course that flows into the sea, due to the irruption of marine waters during the tides in their high tide phase and is the term used in the delta of the Orinoco river in Venezuela in northeastern South America. The most conspicuous bore is called in the Tupi-Guarani language pororoca, a roar that occurs at the mouth of the Amazon River. The bore or, more appropriately, the entry of marine waters during high tide, is the phenomenon that explains the intricacy of the fluvial network in the delta, since many of the pipes constitute momentary spillways for marine waters. For this reason, the sense of direction that the Waraos have when navigating through the delta, even at night when they are guided by the stars, has always been a source of astonishment for the Spaniards. Let us remember that most of the channels or arms of the delta have numerous meanders forming almost complete circles and, in addition, opposing currents according to the phase of the tides: during high tide, the current heads upstream and shortly after the opposite happens.

Economic importance

Currently, the basin is exploited in the forestry aspect, being Ciudad Bolívar the capital of the Bolívar State, the great commercial center together with Ciudad Guayana. Likewise, iron deposits are exploited in the entire area of confluence with the Caroní river, in Cerro Bolívar and Cerro San Isidro. The ports of Palúa and the docking ports of the basic companies in Ciudad Guayana are the centers for handling and shipping iron ore. On the other hand, on the left bank, hydrocarbons are extracted, which are transported from the town of El Tigre to the Jose Industrial Complex and Puerto La Cruz through oil and gas pipelines. It is also of some importance the exploitation of gold in the mines of El Callao and the Mining Arc. The cities near the river are headquarters of mining, metallurgical and hydroelectric companies which have evolved as a thriving well-planned region, including basic companies such as Alcasa, Venalum, Carbonorca (producers of primary aluminum, alumina and carbon anodes for the aluminum industry, respectively), Bauxilum and Ferrominera (extraction, processing and commercialization of bauxite and iron ore) and Siderúrgica del Orinoco (steel). The company Electrificación del Caroní, C.A. (Edelca) and the Corporación Venezolana de Guayana have their headquarters in Ciudad Guayana. Edelca built, operates and manages the Simón Bolívar Hydroelectric Power Plant (the latter is, for now, the third largest in the world, in terms of hydroelectric generation capacity, and gave rise to the Guri reservoir, the second largest lake of Venezuela, located about 80 km upstream from its confluence with the Orinoco, Edelca also manages several hydroelectric plants on the Caroní river: Macagua I, Macagua II and Caruachi, all three located within the urban limit of Ciudad Guayana.

Bridges

The Angostura bridge over the Orinoco River in the Guayana region of Venezuela was designed and built by engineer Paul Lustgarten, a native of the same region, and inaugurated on January 6, 1967 by President Raúl Leoni. At the time of its completion, it was the ninth suspension bridge in the world and the first in Latin America. It is located five kilometers from Ciudad Bolívar and Ciudad Orinoco, connecting the states of Anzoátegui and Bolívar. It has a length of 1678.5 meters, four traffic channels at a height of 17 meters, 14.6 meters wide, at its highest point it rises 57 meters above the river, and has two large steel towers that They support the laying of the cables and are 119 m high.

The Orinoquia Bridge, as it was named on its inauguration day, is a concrete and steel cable-stayed bridge built near Ciudad Guayana, in southern Venezuela. It unites the states of Bolívar and Anzoátegui, becoming the second structure to be built over the Orinoco River after the Angostura bridge. It was inaugurated on November 13, 2006 under the coordination of the Venezuelan Corporation of Guayana and constitutes a mixed road system that also connects the region with the state of Monagas. The final decision on its construction began on the orders of Venezuelan President Hugo Chávez in 2001. The design of the bridge is the work of Guyanese engineer Paul Lustgarten (also designer of the Rafael Urdaneta bridge over Lake Maracaibo and the first one in Angostura). The construction company was the Brazilian Odebrecht and the majority of the capital was provided by the Venezuelan state, through FONDEN (National Development Fund). It has an extension of 3,156 meters, four main towers 120 m high, 39 piers, two abutments, 388 piles, a maximum free height above the water level of 40 meters and a total width of the deck of 24.7 meters, with four circulation channels plus a railway gauge. It also has:

• Link from the motorway Ciudad Bolívar-Ciudad Guayana: 6 km and four channels of 3.6 m;
• Link from Los Pozos (Monagas): 35 km and two channels of 3.60 m;
• From La Viuda (Anzoátegui) to the bridge will travel 125 km with two channels of 3.6 m.

The mixed bridge (road-rail) over the Orinoco River is a cable-stayed type with a fan configuration and H-shaped towers. The transport of the railway facilitates the transport to the rest of the country and the export ports of the iron, steel, aluminum and wood products of the Guayana region. Initially, an investment of 480 million dollars was estimated to carry out the Mixed Bridge Road System project over the Orinoco River, but currently the final cost is around 1,000 million dollars, due to the related works, and due to problems that arose during the construction. 886 million were destined for the construction of the bridge, 270 million for the 166 km of related road and the four road distributors, while for the six annex bridges, 127 million dollars were invested.

The Middle Stone, in the river Orinoco, called a "Nilómetro" of the Orinoco by Alexander Humboldt.

Orinoco River at sunset in the Venezuelan Plains.

Odebrecht is currently building the third bridge over the Orinoco River and it is estimated that the works will be completed in 2013; However, 12 years later, the unfinished work continues.

The Orinoco in culture

In literature

According to Alejo Carpentier, «the Orinoco is a materialization of time in the three Augustinian categories, past time (the time of memory), present time (time of intuition) and future time (time of waiting)».

At the movies

• 1888, El Extraordinario Viaje de la Santa Isabel. Venezuela. 2005
  • Guion: Gustavo Michelena and Alfredo Anzola.
  • Dir.: Alfredo Anzola.
  • Int.: Marco Villarrubia (Jules Verne), Kristin Pardo (Juana de Kermor), Ronnie Nordenflycht (Conde Stradelli), Elba Escobar (Honorine Verne).

It is a film based very loosely on the book The superb Orinoco by Jules Verne.

• Orinoko, New World (1984). Directed by Diego Rísquez.
• Orinoco, the prisoner of sex (1980). Directed by Edwardo Mulargia.
• Murphy's War 1971 British film, directed by Peter Yates. Starring Peter O'Toole and Philippe Noiret.
• The Man of the Future (Beyond Orinoco). Mexican-Venezuelan production of 1965 with Javier Solis and Miguel Ángel Landa.
• In search of the origin of the Rio Orinoco. Expedition Program. (1993). Documentary produced by Radio Caracas Televisión.

On TV

• Star Trip: Deep Space Nine (Star Trek: Deep Space Nine) in season 2, episode 3 (The Block); T2 Ep4 (Invasive Procedures); T2 Ep.6 (Melora); T2 Ep.15 (Paraiso); T2 Ep. 21 (Maquis Part 2); T2 Ep. 26 (Jem'Hadar). T4 Ep. 9 (Bashir, our man). It mentions "Orinoco" as the name of one of the ships of the space station of the series. All ships have names of important rivers.
• The Expanse: Season 1, Episode 4. Mention of spacecraft of the earth with that name.

In music

• Enya, Irish composer of music new age, he titled one of his most popular songs “Orinoco Flow”, translated as “The Orinoco stream”.
• Betulio Medina titled one of his gaitas «Orinoco: Río Hermoso».

In the Venezuelan financial system

• The Banco del Orinoco, whose main office was located in Ciudad Guayana, Bolivar State, was in service from 1980 to 1998 when it was acquired by Corp Banca with which it merged.
• Orinoco insurance. This company in 1999 is acquired and merged by Mercantile Insurance, owned by the homonymous bank.

In the Colombian anthem

The Colombian National Anthem refers to the battle in its third stanza:

IIIFrom Orinoco the channelis filled with spoils;of blood and crying a riverHe looks there..They don't know.souls and eyeswhether admiration or horrorfeel or suffer.

National anthem of the Republic of Colombia.