page_title: Orinoco Basin
section_title: Hydrography
hierarchical_section_title: Orinoco Basin / Relief / Hydrography
caption_attribution_description: La distinta coloración de las aguas del Caroní (aguas oscuras que proceden de la Guayana venezolana), en primer lugar, de las del Orinoco, al fondo.
context_page_description: The Orinoco Basin is the part of South America drained by the Orinoco river and its tributaries. The Orinoco watershed covers an area of about 990000 km², making it the third largest in South America, covering most of Venezuela and eastern part of Colombia.
  The Orinoco is one of the most important rivers in the world due to its length and flow, the extent of its basin and especially its historical importance and economic and the meaning it has had for Venezuela, where most of its basin is spread, with almost two-thirds of it. It is probably the largest river in the world in relation to its basin, similar in extent to that of the Danube but five times greater in volume. Its discharge is the third largest of any river worldwide, after the Amazon and the Congo, and much greater than that of many rivers of greater length and basin area.
context_section_description: The Orinoco, with its tributaries, constitutes an extensive hydrographic network with rivers very flowing and of considerable length. Of all its basin, the longest tributary is the Guaviare, longer (about 1550 km) than the Orinoco itself at the point of its confluence, while the largest is the Caroni. Many of its tributaries are navigable rivers, especially those on the left bank, which come from the Llanos, both Colombian and Venezuelan, while the Guayan rivers (tributaries on the right bank) are more flowing but with jumps and rains, which make them very useful in the production of hydro-electric energy, but without use as navigational routes, except for some very short stretches. There are numerous islands, both rocky (erosion reliefs) and sedimentary (sand and other sediments), as well as many pipes or arms, abandoned meanders and horseshoe lakes.
  The main tributaries on the right bank are the Manaviche, Ocamo, Padamo (with its Matacuni tributary on its left bank), Cunucunuma, Ventuari (very flowing river, with its Manapiare tributary on the right), Sipapo with its tributaries Autana and Cuao, both on the right), Samariapo, Parguaza (with several tributaries with a curious bayonet drainage), Suapure, Cuchivero river (with its tributary Guaniamo, on the left bank, a river where the gold has been exploited for a long time), the Caura (with its Erebato tributary on its left bank), a very flowing river and with one of the most notable leaps of Guayana (not so much because of its height but Caudal), the Pará jump, the Aro and finally the Caroní with its tributary the Paragua, dammed both rivers in the Necoima Canyon or Necuima, in a hydro-electric dam of more than 200 m of height that originates a reservoir, the Lake of Guri, with more than 4000 km² of surface and a production of about 10 million kW/hour, which defines it as one of the most valuable and productive rivers in the world: to date, the production of the Guri hydro-electric power station is only surpassed by the Itaipú hydro-electric power station, in the Paraná River. In the Cuao river basin (except for the long, or horseshoe-shaped lagoons formed by some abandoned meanders), the only lagoon in the basin: the lagoon of King Leopold, so named because it was discovered during an expedition sponsored by King Leopold III Of Belgium a little more than 50 years ago (at the moment it is very easy to observe it through programs with satellite images, generally of free access in Internet). This lagoon has about 400 m of length by 270 of width, approximately. It is the only lagoon in Venezuelan Guiana, which confirms the irregular nature of the relief of this natural region, which is not favorable to them, and also contradicts the myth of the sixteenth century, of the existence of a huge lake (Lake Parima) from which the Orinoco and Amazon rivers were born, with almost all its tributaries.
  On the left bank we can mention the Mavaca, the unique case in the Casiquiare world (which is not a tributary but, on the contrary, an effluent, that is to say, a derivation of the Orinoco that drains its waters towards the Amazon basin through the Negro River), the Atabapo, the four rivers that come from the Colombian territory, which are the Guaviare (with its tributary the Inírida), Vichada, Tomo and Meta. And again in Venezuelan territory, the Apurean rivers to the north of the Meta: Cinaruco, Capanaparo, Arauca and Apure, the latter with numerous tributaries on its left bank gathered in two great rivers, the Portuguesa and Guárico. And some rivers also llaneros of minor importance and caudal, like the Manapire, Iguana, Zuata and Pao. Finally, the Caño Manamo will end up in the Orinoco delta, the Taiga with its tributary by its right margin, the Long Morichal and the Guanipa with its tributary by its left bank, the Amana.
  Each of the named tributaries of the Orinoco River deserves a more detailed study. Also, some problems that are scarcely investigated, such as the different coloration of the waters of these tributaries, as seen in the image, the phenomenon of the lack of cloudin
caption: Confluence of the Caroní in the Orinoco, whose waters are distinguished by the different coloration, whiter in the Orinoco (in the background) and darker in the foreground (Caroni waters). The different width of the fringes is an optical effect by the distance, being the one of the Orinoco much greater.
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