Orinoco

Orinoco refers to the Orinoco River, one of the longest rivers in South America, flowing mainly through Venezuela with a small portion in Colombia. It forms the center of the Orinoco Basin, an extensive watershed of about 880,000 square kilometers, and runs roughly 2,140 kilometers from its headwaters in the Guiana Shield to the Atlantic Ocean, where the river fans into the Orinoco Delta.

The river's headwaters rise on the Venezuelan and Brazilian sides of the Guiana Highlands, and it generally descends northward through varied landscapes, from the nutrient-rich plains of the llanos to tropical lowlands. Its major tributary is the Caroní River, which carries a substantial portion of the basin’s flow. The Casiquiare canal is a natural link that briefly channels water between the Orinoco and the Amazon Basin via the Rio Negro, illustrating the interconnectedness of South American river systems. The lower reaches form the Orinoco Delta, a broad network of distributaries, brackish lagoons, and numerous islands.

Hydroelectric development is a defining feature of the system; the Guri Dam on the Caroní River, near Puerto Ordaz, has created one of the world's largest reservoirs and supplies a significant portion of Venezuela's electric power. The lower Orinoco supports navigation, fisheries, and local transport, while the upper basin sustains diverse tropical and savanna ecosystems.

Ecology and conservation concerns include rich biodiversity, with numerous fish species and unique habitats in both the shield region and delta. The river faces environmental pressures from pollution, mining, oil exploration, damming, and deforestation, with ongoing efforts to balance development and ecological health.