ORINOCO RIVER: CHARACTERISTICS, ROUTE, MOUTH, TRIBUTARIES - GEOGRAPHY - 2024

The Orinoco is the most important river in Venezuela. It also runs through Colombia and has an approximate length of 2,100 km from its source to its mouth, being one of the longest rivers in South America.

Its flow is estimated at 33,000 m ³ / s. which makes it the third largest river in the world, being surpassed only by the Amazon River (Latin America) and the Congo (Central Africa). Due to the rainfall it receives on its way, the Orinoco presents a flood season that reaches its maximum level in August and reaches its minimum in March.

The Orinoco River bathes an area of ​​approximately 1,000,000 km ². Photo: Olga Cecilia Escobar Garcia

The Orinoco passes through seventeen of the twenty-three states of Venezuela, in addition to eleven of the thirty-two departments of Colombia, being a fairly concrete fact of the importance of the river for these two nations.

General characteristics

Course of the Orinoco river in the state of Amazonas, Venezuela. Source: No machine-readable author provided. Jesús Rincón assumed (based on copyright claims).

The Orinoco River is a true giant of the region, not only because of its length and its channel, but also because of the importance it represents in the territory that bathes its waters.

Navigable river

It has all the elements to be considered as a great river artery, navigable along 1,670 kilometers in which it gives direct access to oceanic ships, industrial and commercial ports on land.

Since 1973, the longest international river rally in the world has been held on the river axis of the Venezuelan states Apure and Orinoco. This tour is called 'Our Rivers Are Navigable', organized by a non-profit civil association that bears the same name and covers 2,000 km in Venezuelan and Colombian river waters.

This competition promotes social and environmental conservation work around rivers, as well as international integration in a recreational format for the whole family.

Its basin covers an area of ​​approximately 1,000,000 km ^2, of which 70% is in Venezuelan territory and 30% in Colombian territory.

Bridge over the Orinoco River

Since 1726, navigators and explorers have passed through the natural bridge that connects the Orinoco basin with the Amazon basin through the Brazo Casiquiare, which empties into the Negro River. In 1745 it was officially registered and its existence was disclosed in Europe by the French explorer Charles Marie de La Condamine. Later, in 1800 the explorer and scientist Alejandro de Humboldt confirmed its location and existence.

Economic motor

"The stone in the middle" on the Orinoco River. Source: Guillermo Ramos Flamerich

Much of Venezuela's basic industry is developed and connected on the Orinoco River. Forestry, oil and mining exploitations fundamental to the economy of this country are applied on both margins, together with the presence of national and international river ports that represent connectivity and promote the rise of a solid port economy.

Birth

The Orinoco River is born in the Delgado Chalbaud hill located in Venezuela, in the Parima-Tapirapecó National Park, Amazonas state, at an approximate height of 1,000 meters above sea level.

The first hint that glimpsed its existence dates back to 1498, specifically on August 1, during his third trip to America Christopher Columbus spotted a protrusion of the Orinoco delta while coasting the island of Trinidad and in the presence of the abundant amount of fresh water he supposed that it came from a river on the mainland.

Its official discovery is the credit of Vicente Yáñez Pinzón, Spanish navigator and representative of the interests of the crown. His voyage of exploration began in December 1499, when on the way to Cape Verde his ship was swept off the coast of Brazil by a storm. Later, he skirted them in a northwesterly direction and discovered the mouth of the Amazon River and the Orinoco around January 1500.

Then Diego de Ordaz - Hernán Cortés' companion in Mexico - is recognized as the first explorer of the Orinoco River between 1531 and 1532, when he traced it to the mouth of the Meta and the Atures streams.

In this map you can see the birth:

Route and mouth

From its source, in the state of Amazonas, to its mouth in the Atlantic Ocean, the Orinoco River runs in a general north-south direction, drawing a curve towards the west and then turning east until it reaches its final path in the delta.

These stretches can be divided into three hydrographic regions: upper Orinoco, middle Orinoco, lower Orinoco, and Orinoco Delta.

Upper Orinoco

It goes from its source in the Delgado Chalbaud hill in the state of Amazonas, to its confluence with the Ventuari river. It has a length of 450 km and is completely in Venezuelan territory.

The basin corresponding to this area occupies 101,000 km ² and is connected to the Amazon river basin through the Casiquiare canal.

Middle Orinoco

The surface of this section is shared between Venezuelan and Colombian territory, it has a surface area of ​​598,000 km ² and a length of 500 km. It goes from the confluence of the Ventuari river to Puerto Ayacucho.

Here are the Maipures and Atures rapids, two great geographical landmarks that interrupt river navigation, making it impossible for any vessel to transit. In these sectors the river fords large rocks, forming waterfalls and rapids famous for their tourist attraction.

Lower Orinoco

With 900 km of route, it goes from Puerto Ayacucho to Piacoa, bathing an area of ​​301,000 km ² in Venezuela. In this section, its waters become slower and its channel wider.

Orinoco Delta

In brown delta of the Orinoco river. Source: Gabrielsanz

With an approximate length of 250 km from Piacoa, in a straight line through the main channel that connects the river with the Atlantic Ocean. It has an area of ​​23,000 km ² that increases annually thanks to the sediments carried downstream by the river.

The Orinoco Delta is characterized by the presence of more than 300 streams and countless islands that have been generated by sedimentation over the years. In this map you can see the mouth:

Tributaries

Orinoco River at sunset. Source: Paolo Costa Baldi

More than 2,000 rivers and streams deposit their waters in the Orinoco along its route. Among the most important rivers are Mavaca, Amana, Ocamo, Padamo, Cunucunuma, Yagua, Ventuari, Atabapo, Guaviar, Vichada, Tuparro, Tomo, Guanipa, Vita, Meta, Cinaruco, Tigre, Capanaparo, Arauca, Apure, Guárico, Sipapo, Morichal Largo, Parguaza, Suapure, Manapire, Cuchivero, Zuata, Caura, Aro, Caroní and Uracoa.

One of the most emblematic confluences of the basin is the one between the Caroní and the Orinoco. The chemical difference expressed in the pH, the amount of suspended solids that it carries and the temperature of the water produce an amazing spectacle.

Although the waters of these rivers meet, they do not mix immediately, a phenomenon that can be evidenced by the different color of the waters. The darker Caroni owes its color to the organic acids it contains, a product of the decomposition of the vegetation it encounters along its path.

On the other hand, the Orinoco has a yellowish color due to the sediments that it accumulates and receives from its tributaries. This occurs in the state of Bolívar, in Venezuelan territory and is easily appreciated from the Angostura bridge that connects the cities of Puerto Ordaz and San Félix.

An aboriginal legend provides another explanation for the phenomenon: the rivers represent two lovers who come from different origins. Their union, considered an offense to the gods, caused them to be condemned to be separated without ever being able to unite. The protagonists of the fable defied their tribes and the gods, decided to set off together far away from their homelands and unite forever at sea.

Basin

Orinoco river basin. Source: derived from Rafael de León and Alberto J. Rodríguez Díaz. Edited jointly by the Ministry of Public Works and the Venezuelan Corporation of Guayana (uncopyrighted edition)

The Orinoco river basin has an approximate length of 1,000,000 km ² of territory. On its way its waters cross several natural regions with very different climates and reliefs.

The Colombian and Venezuelan plains occupy 42% of the basin, while the Guiana massif represents 35%. The southern jungles, mainly Colombian, occupy 15% of the basin and the region of the Colombian-Venezuelan Andes 5%. Finally, at its mouth, the delta represents 2% and the coastal mountain range less than 1%.

On the territory of the Orinoco basin there are multiple cities where commercial and industrial activities are carried out that represent a danger to the balance of the region's biodiversity. On the Venezuelan side Puerto Ayacucho, Ciudad Bolívar, Ciudad Guayana, Mérida, San Cristóbal, Barquisimeto, Acarigua, Barinas, Guanare, San Fernando de Apure, San Carlos and Tucupita.

On the Colombian side, the most important cities are Villa Vicencio, Bogotá, Puerto López, Yopal, Arauca, Puerto Carreño, San José del Guaviare and Puerto Inírida.

Flora

More than 17,000 species of plants have been studied in the Orinoco. During its journey it crosses eight large bioregions: high Andes, Andean foothills, coastal mountain range, plains, Amazonas, Orinoco-Delta and North and South Guayana. In Colombia exclusively the high Andes, Andean foothills and Amazon regions; in Venezuela the coastal mountain range, the interior branch and the Orinoco-Delta. The llanos region and southern Guayana are shared.

High Andes Bioregion

Forests, shrubs and moors of the semi-humid Andean biome proliferate. Among the most representative plants in the area are frailejón, cardones, prickly pears, cacti, cedars, mahogany, jobillos, laurels and bucares.

Andean piedmont bioregion

Semi-deciduous forests and xerophytic shrubs abound. The most representative species are ferns, yumbé, laurels, wild mamoncillo, climbers, shrubs, palms and orchids.

Coastal mountain range bioregion

Araguaney. Source: Luisovalles

Presents montane and submontane forests of the coastal mountain range. The tree ferns, the naked Indian and the araguaneyes are abundant. Fruit trees such as passion fruit, guava and jobos. Among the flowers, orchids and bromeliads stand out.

Llanos Bioregion

There are flooded savannas, prairies, gallery forests and estuaries. Typical species are the samán, the merecure, the nacre flower, the water lily, the chaparro, the cañafistolo and the llanera palm.

Amazon Bioregion

Humid forests on the Orinoco River. Source: Pedro Gutiérrez.

Covered with humid forests and flooded savannas of white sand. In this region are the itahuba, caricari, tajibos, cedar, cuta barcina, almandrillo, victoria regia, hevea, palm trees and jatoba.

Orinoco Delta Bioregion

Forests, shrubs and flooded grasslands of the Lower Orinoco River Riparian Corridor. The presence of mangroves and palms stands out.

North and South Guiana Bioregion

Highland savannas, forests and shrubs, humid forests and wooded savannas abound. Also bushes, lianas, ferns, orchids, bromeliads and heliamphoras.

Fauna

Along the Orinoco river basin, a great diversity of species lives. More than 1,000 types of fish, 100 types of reptiles, 300 types of mammals, and 1,300 types of birds have been recorded. In addition, they have studied more than 100 species of dung beetles and an estimated 350 endemic species of butterflies.

Arrau turtle. Source: Luisovalles

Among the fish species, at least 20 have been described, also endemic. The most representative and most valuable for sport fishing are curvina, caribe, horse mackerel, smooth, roncador, dorado, laulau or valón, shaker and sapoara.

The aquatic mammals present in the river ecosystem are very varied. The Orinoco dolphin, known as tonina, and the water dog stand out. In the reptile classification there are some representatives of the region such as the Orinoco caiman, anacondas and the arrau and matamata turtles. Of the amphibians there is a tiny endemic type frog of the region that lives specifically in the tepuis.

The Orinoco river basin represents a great reservoir of bird species, among which the paraulata chote, paraulata montañera, water tiguín, woodpecker habado, veined flytrap, warbler of the puddles, paraulata eye of candil and cristofué stand out.

Also masked sorocuá, yellow-billed royal woodpecker, screaming nuthatch, chusmita egret, cock-of-the-rock, capuchin bird, umbrella bird, bell bird, red wine cotinga, blue and yellow macaw, small hermit, mangrove sparrow hawk and sickle-billed hawk.

Capybara. Source: Fidel León Darder

Many of the mammals that make life in the Orinoco are in danger of extinction, about 6% of the species present in the area. Indiscriminate hunting and overexploitation of the natural space are the main causes. In this region live manatees, jaguars, capybaras, howler monkeys, anteaters, sloths and chigüires.

References

1. Rodríguez, C. Quality of bodies of water: Heres and Caroní municipalities of the Bolívar state. University, Science and Technology Magazine (2012), taken from ve.scielo.org
2. Méndez, A. The papers of Dr. Rafael De León, National Academy of Engineering and Habitat (2008), taken from acading.org.ve
3. Silva, G. The Orinoco river basin: hydrographic vision and water balance. Venezuelan Geographical Magazine (2005), taken from redalyc.org/pdf/3477/347730348007.pdf
4. Biodiversity of the Orinoco River Basin, Alexander von Humboldt Biological Resources Research Institute.
5. Alcalá, C. The fish of the Orinoco Delta. La Salle Foundation for Natural Sciences, taken from fundacionlasalle.org.ve