12 julio, 2024

Orinoco River: characteristics, route, mouth, tributaries

He Orinoco It 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 m3/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 along its route, the Orinoco presents a flood season that reaches its maximum level in August and touches its minimum in March.

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


General characteristics

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 bathed by its waters.

navigable river

It has all the elements to be considered a great fluvial artery, navigable for 1,670 kilometers, giving direct access to ocean-going ships, industrial and commercial ports on the mainland.

Since 1973, the longest international river rally in the world has been held in the fluvial 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 work and environmental conservation around rivers, as well as international integration in a recreation format for the whole family.

Its basin bathes an approximate surface of 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

Much of the Venezuelan basic industry is developed and connected to the Orinoco River. On both sides, forestry, oil and mining exploitations are fundamental for the economy of this country, coupled with the presence of national and international river ports that represent connectivity and promote the rise of a solid port economy.


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 clue that hinted at its existence dates back to 1498, specifically on August 1, during his third trip to America Christopher Columbus saw a ledge of the Orinoco delta when 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, a 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 away by a storm to the shores of Brazil. Later he skirted them in a northwesterly direction and discovered the mouth of the Amazon and Orinoco rivers around January 1500.

Later, Diego de Ordaz – a companion of Hernán Cortés in Mexico – is recognized as the first explorer of the Orinoco River between 1531 and 1532, when he went up it to the mouth of the Meta and the rapids of Atures.

This map shows the birth:

Route and mouth

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

These sections can be divided into three hydrographic regions: high Orinoco, middle Orinoco, low Orinoco and Orinoco Delta.

Upper Orinoco

It goes from its source on the Delgado Chalbaud hill in the Amazonas state, 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 km2 and is connected to the Amazon River basin through the Casiquiare channel.

middle orinoco

The surface of this section is shared between Venezuelan and Colombian territory, it has an area of ​​598,000 km2 and a length of 500 km. It goes from the confluence of the Ventuari river to Puerto Ayacucho.

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

Lower Orinoco

With a 900 km route, it goes from Puerto Ayacucho to Piacoa, bathing an area of ​​301,000 km2 in Venezuela. In this section its waters become slower and its channel wider.

Orinoco Delta

With an approximate length of 250 km from Piacoa, in a straight line along the main channel that joins the river with the Atlantic Ocean. It has an area of ​​23,000 km2 that increases annually thanks to the sediments carried by the river downstream.

The Orinoco Delta is characterized by the presence of more than 300 pipes and innumerable islands that have been generated by sedimentation over the years. This map shows the mouth:


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 that occurs between the Caroní and the Orinoco. The chemical difference expressed in the pH, the amount of suspended solids that it drags and the temperature of the water produce an amazing spectacle.

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


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

An aboriginal legend offers 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, they decided to leave together far away from their territories of origin and be united forever in the sea.


The Orinoco river basin has an approximate length of 1,000,000 km2 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 Colombian-Venezuelan Andes region 5%. Finally, at its mouth the delta represents 2% and the coastal range less than 1%.

On the territory of the Orinoco basin, multiple cities are located where commercial and industrial activities are carried out that represent a danger to the balance of biodiversity in the region. 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.


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

High Andes Bioregion

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

Andean foothills bioregion

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

Coastal Cordillera Bioregion

It presents montane and submontane forests of the coastal mountain range. Tree ferns, the naked Indian and the araguaneyes are abundant. Fruit trees such as parchita, guava and jobos. Among the flowers, orchids and bromeliads stand out.

plains bioregion

There are flooded savannahs, meadows, gallery jungles and estuaries. Typical species are the saman, the merecure, the mother-of-pearl flower, the water lily, the chaparro, the cañafistolo and the llanera palm.

Amazon Bioregion

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

Orinoco Delta Bioregion

Floodable forests, shrublands and grasslands of the Lower Orinoco River Riparian Corridor. The presence of mangroves and palms stands out.

North and South Guyana Bioregion

Savannahs, forests and shrublands of the high plateau, humid forests and wooded savannahs abound. Also scrubs, lianas, ferns, orchids, bromeliads and heliamphoras.


A great diversity of species lives along the Orinoco river basin. More than 1,000 kinds of fish, 100 kinds of reptiles, 300 kinds of mammals, and 1,300 kinds 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.

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

The aquatic mammals present…

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