The Caroní River is a major river of the Orinoco basin in South America, having its source in South Eastern Venezuela, in the Guiana Highlands. It is a blackwater river, with the dark color of the water due to leaching from decomposed plant sediments, not from the amount of iron around the riverbed as is often suggested. The Caroní River meets with the Orinoco River and merges into it for approximately 13km. The two rivers meet where Ciudad Guayana (city of Guiana) now exists. The power of the water has been used by man to produce hydroelectric energy. Today it has 4 different dams.