A common name (meaning "black river" in
Spanish and
Portuguese)
given to many rivers in
South America that carry dark sediment.
The largest
tributary of the
Amazon River, Río Negro begins
as
Río Guainia in eastern
Colombia. Guainia eventually reaches
the border between Colombia and
Venezuela, and becomes the border, flowing
past the town of
Maroa. At some point in the 100 km between Maroa and
the junction of
Brazo Casiquiare, the river changes its name. The river
then flows SSE past
San Felipe, Colombia and
San Carlos de Río
Negro, Venezuela until it reaches the town of
Cucui, where it enters
Brazil and descends into the
rain forest.
Picking up tremendous amounts of water from the rain forest, as well
as the dark sediment that gives the river its name, the river swells to
a braided channel, 40 kilometers wide, with island groups so large they
are referred to as archipelagoes. Some points in the river are so wide that neither shore can be seen: Water stretches to the horizon in all directions, as if one were on the high seas.
Río Negro flows east-southeast for another 1000 km or so until
it meets Río Solimões (Also known as the "Upper Amazon")
at the city of Manaus. The dark waters of Río Negro and the lighter
waters of Solimões flow side-by-side for another 40 km until they
finally mix.
A second Río Negro lies in west-central Brazil. 200 km long,
it flows west through the southern portion of the swampy
Pantanal region,
lending its name to the southern third. The river empties into the Río
Paraguay 100 km southeast of
Corumba.
Just downstream from the Pantanal Río Negro, a third Río
Negro collects the Rio Otuquis in
Bolivia, and flows southeast for about
75 km as the border between Bolivia and
Paraguay. Its confluence with
Río Paraguay is the point where Brazil, Paraguay, and Bolivia meet.
A fourth Río Negro is the largest river entirely in
Uruguay,
flowing about 500 km WSW from
Bagé just over Uruguay's northeastern
border with Brazil until it meets the
estuary of Río Uruguay.
This river noted for its two hydroelectric dams,
Rincón del Bonete,
which creates the largest artifical lake in South America, and
Rincón
de Baygorria further downstream.
A fifth Río Negro flows for about 150 km southeast through
Argentina's
Gran Chaco until it mees
Río Paraná at the city of
Resistencia.
In the region where the
Pampas meet
Patagonia, another Argentine
Río Negro collects Río Neuquén and Río Limay
near the Argentine city of Neuquén, and flows 400 km ESE into the
Atlantic.
Finally,
Guatemala's Río Negro is also known as Río
Chixoy, site of the infamous
Chixoy Dam Massacre. It winds easterly
then northerly for 150 km through southwestern Guatemala until it changes
its name to Río Salinas, and becomes the border between Guatemala
and
Mexico.
There are more, but I'm tired.
Descriptions are mine, from looking at maps in
The Great Geographical
Atlas,
Rand McNally & Co.,
1982 rev.
1989