The Caroní River is the second most important river of Venezuela, the second in flow, and one of the longest, from the Kukenan tepui through to its confluence with the Orinoco River. The name "Caroní" is applied starting from the confluence of the Kukenan with the Yuruaní River at from the source of the Kukenan and from its discharge in the Orinoco. The confluence takes place in Bolivar State. Hydraulic regime The Caroní is one of the rivers with the highest discharge rates in the world, with respect to the area of its basin. The average discharge is , with variations caused by the wet/dry seasons. The average maximum discharge is , and the average minimum is . Among the historic extremes are . The Caroní supplies 15.5 percent of the discharge of the Orinoco river. One of the characteristics of the Caroní's water is the dark color, caused by the high amount of humic acids due to the incomplete decomposition of the phenol content of the vegetation. The Caroní thus belongs to the blackwater rivers, as does the Negro River, or Rio Negro in Brazil, Venezuela and Colombia. In the late 1940s diamonds were found in the Caroní basin near the famous Lost World Region which then was accessible only by aircraft and four wheel drive vehicles. Basin The river drains the Guayanan Highlands moist forests ecoregion. The Caroní basin covers and is part of the Orinoco basin, the most important river of Venezuela. This means for the two big rivers that they have very similar hydrographic characteristics. The Caroní itself and its tributary the Paragua are rivers with a staircase, in the sense that many falls and rapids are alternated with stretches with gentle slopes, with many meanders and oxbow lakes (naturally cut off meanders). Among the most important falls of these rivers and their tributaries are Angel Falls, with the highest free fall of the world, almost , and Kukenan Falls, the tenth on the world scale with a free fall. Others falls with less height but high volume are the Aponwao, Caruay and La Llovizna waterfalls. Hydroelectric power Because of its high discharge rate, with a yearly average of and a steep slope, the Caroni ideally suited for the generation of hydroelectric energy with four plants along its course (Macagua I, II and III), near its mouth, the Caruachi, some aback, and lastly the plant of