It originates Cassiquiare a hydrological phenomenon (long story), passing the voluminous waters of the Orinoco by the narrow gorge of Tama-size stone, just under two miles. below, when the moving mass increases in speed and using gradients (Divortium Aquarium) breaks the left bank of river pouring over there 30% of the water heading west, through a mouth of 200 mt. This initial spill or overflow the Orinoco comes after a journey of 370 km. and a height of 21 mt. flows into the river Guanía, with a width and almost 1,000 mt. It is estimated that its basin covers about 35,000 km2.
Just a few kilometers of the bifurcation, and the channel starts receiving its own tributaries Caripo the first pipe, the second a few kms. below, the Pamoni, then Pasiba the Siapa, the union Pasimoni YATU-Baria. The largest, the Siapa Emoni its navigable tributaries, and Matapirí Manipitare. After the first major flood in Upper Siapa or Idapa, it receives among others, the Brown River.
The Baria born at Cerro La Neblina, descends the grand and imposing canyon of Baria and upon reaching the bottom and flat, is divided into many small channels, comparable to a capillary system, which form a network crisscrossing running towards North, but one of those channels southward thickening runs its course then streams that flow into it, which took the name of Canal Maturacá, wearing these black waters of the stormy river Cauaburi Baria, in Brazil. On the site hua is the milestone that channel bordering Brazil, being able to say that the jump upstream and Venezuela are those that have fallen are from Brazil. Maturacá Channel is a smaller replica Cassiquiare Arm, for it removes Baria river waters in Venezuela, to take them to a Black River tributary in Brazil, the Cauaburi.
The main tributaries of Cassiquiare born in the mountainous south, bordering with Brazil to run north and empties into the canal, left bank, which is almost a sub watershed; configure a wonder of nature, as the only important navigable natural channel, so far known, that unites two very different systems and hydrographic charts. This allows us to browse without interruption from anywhere in the Orinoco to the Amazon River and from there to any of its navigable tributaries, or what is equally fantastic, navigate to any South American country except Chile.
We know this road, having made four return trips on these same rivers, from the Orinoco to San-Santarem on the Amazon River, also several air travel in the same places. Many studies have been made and designed for the use of this important internal waterway of America, which has already been determined trafficked and tested by scientists and explorers.
THE Black River system makes Guanía-Venezuela-Colombia limits. Guainia was born in Colombia and from the flood of Deer Island and starts running towards the South, as the border with Colombia, to San Jose to the South Island, which falls squarely on Brazil, taking his black flow to the river Amazon. When you receive your great tributary, the Cassiquiare Black River starts to call. After entering Venezuela, receives several tributaries, such as Pimichin, Guape and Colon, but specially mentioned the San Miguel or Conorichite, which having its origin in estuaries or lagoons Macavacape, runs westward. Almost in the same gaps comes from a small pipe that falls to Cassiquiare on his right and is called The Waste pipe. In the season of greatest rains these two streams of water on their heads are joined, allowing a person very knowledgeable in these areas, can get out of Cassiquiare by the Disposal and go right on the San Miguel River or Conorichite Guanía, Victorino coming to Maroa or vice versa, saving several days sailing to make the trip for this irregular way, without using normal-Guanía Cassiquiare.
Compared with the state's area, it is estimated that the water collected by the Orinoco and its tributaries, covering an area of 115,000 km2, covering an area of almost 70%, in terms of the waters draining the Black River and arrive the Amazon River, irrigate an area of 52,000 km2. equal to 30%. These two basins are connected by the arm Cassiquiare.
The upper regions of Parime and part of its foothills are also the highest parts of the main water courses, where there is a very considerable hydropower potential of over 100 kw per km2., Partly caused by the altitude steep slopes, but helped by the very own high rainfall in the area. Also in the southern border where the upper parts of the rivers YATU, Siapa and Mavaca, we have determined a high hydroelectric potential very close to the 100 kw. per km2.
It is assumed that this area would have a tremendous South geo-political importance, as it is located in the north central part of South America, at the point of contact between Venezuela, Colombia and Brazil. Precisely where Black River connects us with the vast network of rivers of the Amazon basin it navigable rivers confluence of all South American countries except Chile.
We must also mention the main tributaries of the Orinoco that come from Colombia, all waterways: Tomo, Tuparro, Vichada, Sama, Matabeni, Guaviare, the Guasacavi that falls through Atabapo River.
It is estimated that in the known part of the rivers of this state is at least 38% of the gross national hydroelectric potential.
We note the major rivers, both tributaries of the Orinoco as major tributaries that feed these, the same with the arm Cassiquiare and Guanía-basin of the Black River. Lengths are in km. some estimates.
Orinoco 2.800 - Atabapo 130 - Mavaca 142 - Atacavi 101 - Ocamo 230 - Temi 103 - Iguapo 50 - aname 104 - Cunucunuma 205 - Patacame 40 - Yagua 87 - Ucaquén 36 - Puruname 78 - Sipapo 165 - Cataniapo 68 - Guayapo 145 - Ventuari 460 - Autana 108 - Manapiare 126 - Cuao 195 - Parucito 86 - Brazo Casiquiare 370 - Parú 216 - Pamoni 92 - Asita 115 - Pasiba 77 - Marieta 67 - Pasimoni 76 - Marueta 50 - Yatúa 103 - Guapuchí 71 - Baría 110 - Yureba 63 - Siapa 215 - Uesete 68 - Matapire 194 - Yatiti 40 - Manipitare 120 - Hacha 60 - Castaño 103 - Antabare 60 - Guainía 88 - Río-Negro 320 - Yakiguapo 41 - San Miguel 102 - Padamo 135 - Tirikín 70 - Botamo 80 - Pimichín 32 - Metaconi 175 - Continamo 95....