The Uruguay River ( ; ) is a major

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It flows from north to south and forms parts of the boundaries of

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

, separating some of the Argentine provinces of La Mesopotamia from the other two countries. It passes between the states of Santa Catarina and

Rio Grande do Sul Rio Grande do Sul (, ; ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative units of Brazil#List, fifth-most populous state and the List of Brazilian s ...

in Brazil; forms the eastern border of the provinces of

Misiones Misiones (, ''Missions'') is one of the 23 provinces of Argentina, located in the northeastern corner of the country in the Mesopotamia region. It is surrounded by Paraguay to the northwest, Brazil to the north, east and south, and Corrientes P ...

Corrientes Corrientes (; Guaraní: Taragui, literally: "Currents") is the capital city of the province of Corrientes, Argentina, located on the eastern shore of the Paraná River, about from Buenos Aires and from Posadas, on National Route 12. It has ...

and Entre Ríos in Argentina; and makes up the western borders of the departments of Artigas, Salto,

Paysandú Paysandú () is the capital and most populous city of the Paysandú Department in western Uruguay. Located on the banks of the Uruguay River, it is the country's List of cities in Uruguay, fourth-largest city and a vital cultural and economic hu ...

, Río Negro, Soriano and Colonia in Uruguay.

Etymology

The name of the river tends to comes from the Spanish settlers' interpretation of the

Guaraní language Guarani (Avañe'ẽ), also called Paraguayan Guarani, is a language of South America that belongs to the Tupi–Guarani branch of the Tupian language family. It is one of the two official languages of Paraguay (along with Spanish), where i ...

word the inhabitants of the region used to designate it. There are several interpretations, including "the river of the

uru Uru or URU may refer to: Language * Uru dialect of Central Kilimanjaro, a Bantu language of Tanzania * Uru language, the extinct language of the Uros, an Amerindian people * Urumi language, an extinct language of the Amazon region of Brazil * U ...

(an indigenous bird)", and " iver ofthe uruguá" (an indigenous

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

, '' Pomella megastoma'').

Course

The river measures about in length and starts in the

Serra do Mar The Serra do Mar (; ) is a system of mountain ranges and escarpments in Southeast Region, Brazil, Southeastern Brazil. Geography The Serra do Mar runs parallel to the Atlantic Ocean coast from the state of Espírito Santo to southern Santa Ca ...

, where the Canoas River and the

Pelotas River The Pelotas River ( ) is a river in southern Brazil, and a tributary of the Uruguay River. The river originates in the Serra Geral at Alto do Bispo and flows northeast for before meeting the Canoas River, forming the Uruguay River. It forms ...

are joined, at about

above mean sea level Height above mean sea level is a measure of a location's vertical distance (height, elevation or altitude) in reference to a vertical datum based on a historic mean sea level. In geodesy, it is formalized as orthometric height. The zero level ...

. At this stage, the river goes through uneven, broken terrain, forming

rapids Rapids are sections of a river where the river bed has a relatively steep stream gradient, gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are needed for a rapid t ...

and falls. Its course through

is not navigable. An unusual feature of the Uruguay River is a submerged

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...

. This canyon formed during the Ice Age, when the climate was drier and the river was narrower. Its depth is up to below the bottom of the river channel and it is one-eighth to one-third as wide as the river. The canyon is only visible in two places, one of which is the Moconá Falls (also called the Yucumã Falls). However, the falls are not visible for 150 days per year and become more like rapids when they are not visible. Unlike most

waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...

s, the Moconá Falls are

parallel Parallel may refer to: Mathematics * Parallel (geometry), two lines in the Euclidean plane which never intersect * Parallel (operator), mathematical operation named after the composition of electrical resistance in parallel circuits Science a ...

to the river, not

perpendicular In geometry, two geometric objects are perpendicular if they intersect at right angles, i.e. at an angle of 90 degrees or π/2 radians. The condition of perpendicularity may be represented graphically using the '' perpendicular symbol'', � ...

. The falls are to high and between and wide. They are from the mouth of the river. The

Turvo State Park The Turvo State Park () is a state park in the state of Rio Grande do Sul, Brazil. It protects the last large area of well-preserved Upper Uruguay forest in the state, which is home to several rare or endangered species. The park is best known fo ...

, created in 1947, protects the Brazilian side of the falls. Together with the

Paraná River The Paraná River ( ; ; ) is a river in south-central South America, running through Brazil, Paraguay, and Argentina for some ."Parana River". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. ...

, the Uruguay forms the

Río de la Plata The Río de la Plata (; ), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda, Colonia, Punta Gorda. It empties into the Atlantic Ocean and ...

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime enviro ...

. It is navigable from around Salto Chico. Its main

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

is the Río Negro, which is born in the south of Brazil and goes through Uruguay for 500 km until its

confluence In geography, a confluence (also ''conflux'') occurs where two or more watercourses join to form a single channel (geography), channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main ...

with the Uruguay River, which is located 100 km north of the Uruguay's confluence with the Río de la Plata, in Punta Gorda, Colonia Department, Uruguay. The river is crossed by five international bridges called (from north to south): Integration Bridge and

Paso de los Libres-Uruguaiana International Bridge Paso or PASO may refer to: People * Fernando del Paso (born 1935), Mexican novelist * Juan José Paso, (1758–1833), Argentine politician Other uses * Paso (float), an elaborate float made for religious processions * Paso (theatre), a seventeent ...

, between Argentina and Brazil; and the Salto Grande Bridge, General Artigas Bridge and

Libertador General San Martín Bridge The Libertador General San Martín Bridge () is a cantilever road bridge that crosses the Uruguay River and joins Argentina and Uruguay. It runs between Puerto Unzué, near Gualeguaychú, Entre Ríos Province, Argentina, and Fray Bentos, Río Ne ...

between

and

. The

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

of the Uruguay River has an area of . Its main economic use is the generation of

hydroelectricity Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

and it is dammed in its lower portion by the Salto Grande Dam and by the

Itá Dam Itá may refer to: *Itá, Paraguay Itá is a city and a district located along the 35th kilometer of Ruta 1 in the Central Department of Paraguay. Etymology Its name means "stone" in the sweet Guaraní, also known as the "Capital of Ceramics ...

upstream in Brazil.

Discharge

Average monthly discharge at Salto Grande: Mean annual discharge at Salto Grande, (): Multiannual average discharge:

Tributaries

The main tributaries from the mouth: ^* Period: 1971–2000

Cellulose plant conflict

Argentina and Uruguay experienced a conflict over the construction of

pulp mill A pulp mill is a manufacturing facility that converts wood chips or other plant fiber sources into a thick fiber board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical, or ...

s on the Uruguay River. Two European companies, ENCE and Botnia, proposed building

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

processing plants at

Fray Bentos Fray Bentos () is the capital city of the Río Negro Department, in south-western Uruguay, at the Argentina-Uruguay border, near the Argentine city of Gualeguaychú. Its port on the Uruguay River is one of the nation's most important harbours. T ...

, Uruguay, opposite Gualeguaychú, Argentina. According to a 1975 treaty, Argentina and Uruguay were supposed to jointly agree on matters relating to the Uruguay River. Argentina alleged that Uruguay broke the treaty. Additionally, Argentina believed the Finnish company Botnia was polluting the fish and the overall environment of the river while Uruguay believed that the plant was not depositing a large amount of toxins in the Uruguay River. Starting in April 2005, residents of Gualeguaychú, as well as many others, protested, claiming that the plants would pollute the river shared by the two countries. Early in 2006, the conflict escalated into a

diplomatic crisis Diplomatics (in American English, and in most anglophone countries), or diplomatic (in British English), is a scholarly discipline centred on the critical analysis of documents, especially historical documents. It focuses on the conventions, pr ...

, compelling one of the companies move the project south. Beginning in December 2005, the international bridges linking the Argentine province of Entre Ríos with Uruguay were intermittently blockaded by Argentine protesters, causing major disruptions in commercial traffic and tourism. In 2006, Argentina brought the dispute before the

International Court of Justice The International Court of Justice (ICJ; , CIJ), or colloquially the World Court, is the only international court that Adjudication, adjudicates general disputes between nations, and gives advisory opinions on International law, internation ...

. The ICJ completed hearings between Argentina and Uruguay regarding the dispute on October 2, 2009. In 2010, the court ruled that although Uruguay failed to inform Argentina of the construction of the pulp mills, the mills did not pollute the river, so closing the remaining pulp mill would be unjustified. Later in 2010, Argentina and Uruguay created a joint commission to coordinate activities on the river.

Links across the Uruguay

The course of the Uruguay is crossed by the following bridges, beginning upstream:

References

External links

*
Salto Grande Hydroelectric System
* * *
"Map of the Uruguay River from Yapeyu to the Farm of Sn. Gregorio"
from 1784 {{Authority control Rivers of Santa Catarina (state) Rivers of Rio Grande do Sul Rivers of Uruguay Rivers of Argentina Argentina–Brazil border Argentina–Uruguay border International rivers of South America Border rivers Rivers of Misiones Province Rivers of Entre Ríos Province Rivers of Corrientes Province