The plain of the Orinoco is a region of plains located within the Orinoco basin, in South America, between the territories of Venezuela and Colombia.
The plain territory of the Orinoco basin is one of the types of relief found within it, the other being the massifs (or shields), depressions and mountain ranges.
It covers a total of 525,000 square kilometers, distributed in 240,000 km in Venezuelan territory and 285,000 km in Colombian territory.
The plains of the Orinoco are plains of accumulation. This means that they were formed as a result of a long process, millions of years, of accumulation of sediments carried by the rivers that pass over them.
Since the plains are little inclined, the speed at which the water of their rivers transits is slower.
These rivers originate and descend from much higher mountain ranges, whereby the sediments dragged on accumulated when they reached the less inclined plains of the plains, until gradually forming the plains that we know today.
Types of plains found in the Orinoco basin
Pre-level the piedmont
They are the plains that lie between the feet of the mountain ranges and the plains. Around or within the piedmont can be intercalated valleys, as it happens in the Andes, where there are valleys of re-excavado fluvial with heights between the 500 and 1000 meters.
Llanos Altos
They are plains that exceed 200 meters above sea level, which is why they are less prone to flooding.
This type is the best of the plains soils, since they are not healthier and the agricultural activity in them is better.
Low Llanos
The low plains are plains whose altitude is below 200 meters above sea level. For that reason, in the rainy season they can get flooded.
Territories covered by the Orinoco Plain
Colombia
The plains of the Orinoco that are in the territory of Colombia receive the name of"Orinoquía"or"plains orientales", because they are located in the east of the country.
They cover about 285,000 square kilometers, and are one of the 6 natural regions that exist in the country.
They are delimited as follows: to the north and east they border Venezuela, to the south with the Colombian Amazonian region, and to the west with the Colombian region of the Andes.
The plains of the Colombian Orinoquía cover the departments of Arauca, Casanare, Meta and Vichada, and scarce spaces of the departments of Boyacá, Caquetá and Guaviare.
The subregions of the Colombian plains are the following:
- Andean Piedemonte, located at the foot of the Eastern Cordillera of the Colombian Andes, with an altitude between 300 and 700 msnm and covering part of the departments of Arauca, Caquetá, Casanare and Boyacá
- Goal Plains
- Plains of Guaviare
- Swamps of Arauca
- Serranía de la Macarena.
The Andean piedmont is the western part of the plains of Colombia, and is characterized by a humid environment and the nutrient richness of its soils.
The eastern plains are located east of the Meta river, which is the dividing line of both plains, in the departments of Vichada and part of the territory of Guaviare, and are characterized by experiencing a long dry season in the year and by scarcity of nutrients in their rivers and soils.
Venezuela
The plains of the Orinoco located in the Venezuelan territory extend in a territory near the 240,000 square kilometers.
They are delimited as follows:
- In the north they limit with the Serrania of the interior of the Cordillera of the Venezuelan Coast
- In the south, the Orinoco river indicates its limit with the formations of the shield Guayanés
- In the west they delimit with the system of the Cordillera de los Andes
- In the east they extend to the plain of the Orinoco Delta, that is, to its mouth with the Pacific.
The whole territory mentioned above belongs to the Venezuelan states of Apure, Barinas, Portuguesa, Guárico, Anzoátegui, Monagas and Cojedes.
The Venezuelan plains are classified in two ways: by the type of plain, and by their geographical distribution.
By the type of plain there are:
- The Llanos Altos (Barinas, Portuguesa, Guárico and Cojedes), which are not floodable because their height varies between 250 and 500mts above sea level
- The low plains (Apure), flooded in the rainy season by its low height
- The piedmont, that are within the classification already mentioned of the Llanos Altos (Barinas and Portuguesa), and that are formed at the foot of the mountain range of the Andes (Barinas and Portuguese).
According to their geographical distribution, they are divided into three areas: the western plains (Portuguesa, Barinas and Guárico); the central plains (Guárico and Cojedes); and the eastern plains (Anzoátegui and Monagas).
Climate, flora and fauna
In the Orinoco plain there are only two seasons or seasons: the dry season and the rainy season.
The average temperature of this region is usually hot, always higher than 23 ° C. On the other hand, in this relief dominate the environments of savannah, gallery forests and pastures of seasonal grasses.
Most plains are savannahs without any trees, covered with grasses and rushes in the lower parts, and with long-stemmed grasses in drier. Characteristic of this region are small groups of trees known as"bushes"and the llanera palms.
As for its fauna, the plains of the Orinoco possess a great diversity of species, being considered one of the richest zones of the world in birds for being the habitat of herons, parrots, numerous species of hummingbirds, corocoros, geese of the Orinoco, toucans, birds of prey, macaws, among others.
Terrestrial mammals include howler monkeys, known as araguatos, which abound in the forests and jungles of the galleries (jungle areas found in the wettest areas of the savannah).
In addition, they can be seen in different species of reptiles, jaguars, deer, rabbits, among others.
Economic activity and resources
The main economic activities carried out in the region of the Orinoco plains, thanks to the fertility of many of its soils, are livestock and agriculture. To a lesser extent fishing also occurs.
The main agricultural products of the region are rice, bananas, maize, African palm, cocoa, oil palm, cassava, sorghum, soybeans, sesame, sugar cane, caraota, beans, coffee, tobacco, yams, potatoes, among others.
On the other hand, in the Venezuelan lands of Barinas, Monagas, Guárico and Anzoátegui, and in the Colombian departments of Arauca, Meta, Casanare there are oil and gas reserves.
References
- Britannica Encyclopedia. Llanos [online]. Consulted on September 1, 2017 on the World Wide Web: britannica.com
- CUNILL, P. (2000). Venezuela for young people. Volume 2: Geography. Venezuela: Editions Ge.
- GÓMEZ, A. (1991). Indians, Settlers and Conflicts: A Regional History of the Eastern Plains, 1870 - 1970 [online]. Consulted on September 1, 2017 on the World Wide Web: books.google.com
- Page 1 Travelers to South America [online]. Consulted on September 1, 2017 on the World Wide Web: scielo.cl
- SILVA, G. (2005). The Orinoco River Basin: Hydrographic Vision and Water Balance [online]. Consulted the 2 of September of 2017 in the World Wide Web: saber.ula.ve
- Wikipedia The Free Encyclopedia. Consulted on September 1, 2017 on the World Wide Web: Wikipedia.org