NASA photo of theRío de la Plata looking from northwest to southeast.Buenos Aires is visible on the right bank near theParaná River delta. River sediments turn its water brown as far asMontevideo, visible on the left bank at the outer estuary.
Map of theRío de la Plata basin, showing the Río de la Plata at the mouths of the Paraná and Uruguay rivers, near Buenos Aires
The river is about 290 kilometres (180 mi) long and widens from about 2 kilometres (1.2 mi) at its source to about 220 kilometres (140 mi) at its mouth.[8] It forms part ofthe border betweenArgentina andUruguay. The name Río de la Plata is also used to refer to the populations along the estuary, especially the mainport cities ofBuenos Aires andMontevideo, whereRioplatense Spanish is spoken andtango culture developed. The coasts of the river are the most densely populated areas of Uruguay and Argentina.[3]
Though it is generally spoken of as a river, the Río de la Plata is considered by somegeographers to be a largebay ormarginal sea of the Atlantic Ocean.[3][8] For those who regard it as a river, it is the widest in the world, with a maximum width of about 220 kilometres (140 mi) and a total surface area of about 35,000 square kilometres (14,000 sq mi).[3]
A submergedshoal, theBarra del Indio, divides the Río de la Plata into an innerfreshwater riverine portion and an outerbrackish estuarine portion.[9] The shoal is located approximately betweenMontevideo and Punta Piedras (the northwest end ofSamborombón Bay). The innerfluvial zone is about 180 kilometres (110 mi) long and up to 80 kilometres (50 mi) wide, with a depth which varies from about 1 to 5 metres (3.3 to 16.4 ft); the depth of the outer estuary zone increases from 5 to 25 metres (16 to 82 ft).[9] The river's discharge is strong enough to prevent saltwater from penetrating to the inner portion.[10]
The Río de la Plata behaves as anestuary in which freshwater and seawater mix. The freshwater comes principally from theParaná River (one of the world's longest rivers and La Plata's main tributary) as well as from theUruguay River and other smaller streams. Currents in the Río de la Plata are dominated bytides reaching to its sources and beyond, into the Uruguay and Paraná rivers.[8] Both rivers are tidally influenced for about 190 kilometres (120 mi).[3] Thetidal ranges in the Río de la Plata are small, but its great width allows for atidal prism important enough to dominate the flow regime despite the huge discharge received from the tributary rivers.
The river is asalt wedge estuary in which saltwater, being denser than freshwater, penetrates into the estuary in a layer below the freshwater, which floats on the surface. Salinity fronts, orhaloclines, form at the bottom and on the surface, where fresh and brackish waters meet. The salinity fronts are alsopycnoclines due to the water density discontinuities. They play an important role in the reproductive processes of fish species.[9]
Satellite image of the Paraná and Uruguay rivers emptying into the Río de la Plata. Due to the relatively calm surface of the estuary and the angle of the Sun relative to the satellite, the current of the river flowing out into the Atlantic is visible.
The Río de la Plata'sdrainage basin (sometimes called the Platine basin or Platine region)[11][12] is the 3,170,000 km2 (1,220,000 sq mi)[3]-3,182,064 km2 (1,228,602 sq mi) hydrographical area that drains to the Río de la Plata. It includes areas of southeasternBolivia, southern and centralBrazil, the entire country ofParaguay, most ofUruguay, and northernArgentina. Making up about one fourth of the continent's surface, it is the second largestdrainage basin in South America (after theAmazon basin) and one of the largest in the world.[4]
Nomadic aboriginal people inhabited the Río de la Plata region for thousands of years before European settlers arrived, and their descendants continue to live in the region to this day.[13][14][15]
The Río de la Plata was first explored by the Portuguese in 1512–13.[16][17] The Spanish first explored it in 1516, when the navigatorJuan Díaz de Solís traversed it during his search for a passage between the Atlantic and the Pacific Oceans, calling it the Mar Dulce, or "freshwater sea".[3] The Portuguese navigatorFerdinand Magellan briefly explored the estuary in 1520 before his expedition continued its circumnavigation,[3] and in 1521,Cristóvão Jacques also explored the Plate River estuary and ascended the Parana River for the first time, entering it for about 23 leagues (110 km) to near the present city ofRosario.[18]
ExplorerSebastian Cabot made a detailed study of the river and its tributaries and gave it its modern name. He explored the Paraná and Uruguay rivers between 1526 and 1529, ascending the Paraná as far as the present-day city ofAsunción, and also explored up the Paraguay River. Cabot acquired silver trinkets trading with theGuaraní near today's Asunción, and these objects (together with legends of a "Sierra de la Plata" in the South American interior brought back by earlier explorers) inspired him to rename the river "Río de la Plata" ("River of Silver").[3]
The first European colony was the city of Buenos Aires, founded byPedro de Mendoza on 2 February 1536. This settlement, however, was quickly abandoned; the failure to establish a settlement on the estuary led to explorations upriver and the founding of Asunción in 1537. The area was visited byFrancis Drake's fleet in early 1578, in the early stages of his circumnavigation.[19] Buenos Aires was re-founded byJuan de Garay on 11 June 1580.[3]
During the colonial era, the Río de la Plata was made the center of theGovernorate of the Río de la Plata. The Río de la Plata region, particularlyBuenos Aires, was a significant site of trade throughout the 17th century. The Crown initially intended Buenos Aires to be a military establishment for the protection of thePotosí mines, but it soon became evident that a settlement large enough to provide military defense would attract trade. The primary export was silver from the mines of Potosí, and imports generally included European luxury goods, slaves, and sugar. This trade occurred outside of the fleet system authorized by the Spanish Crown, and therefore was generally considered "illicit". However, under the monarchy of theSpanish Habsburgs, the line between licit and illicit trade was quite blurry. Crown officials and military outposts in Buenos Aires often relied upon profits from illicit trade to support their administrative structures.[20]
Under theBourbon monarchy, the governorate was elevated to theViceroyalty of the Río de la Plata in 1776. This occurred as a result of theBourbon Reforms, which attempted to restore the decaying wealth of the Spanish Crown. The reforms elevated the status of trade along the Río de la Plata and expanded what constituted "legal" trade so that the Crown could tax trade which had previously been "contraband". However, the plan did not go as intended. Although trade along the Río de la Plata flourished, very little silver was actually remitted to the Crown. Then, Spanish war with Britain and the simultaneous eruption of revolts in the mining regions of Peru led to a shortage of silver, putting strain on the merchant class of Buenos Aires. This caused a schism between merchants who wanted to try to continue reviving the Spanish Empire through silver trade and those who wanted to move on from silver and prioritize agricultural exports, ultimately tearing at the fabric of the Río de la Plata region's relationship with the Spanish Empire.[21]
In 1806 and 1807 the river was the scene of an importantBritish invasion that aimed to occupy the area and was defeated by the local garrison and population.
In the first major naval engagement of the war, an Argentine squadron left port in the early hours of February 9 to challenge the blockade. The battle was inconclusive, with the Argentine fleet breaking contact and the Brazilian admiral failing to give chase.[23]
In July 29, a Brazilian fleet led by the English admiralJames Norton engaged Brown's fleet nearEnsenada. Norton split his force, catching the Argentine line between two fires and causing significant casualties. William Brown's flagship, the frigate25 de Mayo, sank after the battle as a result of the damage received.[24]
In 8–9 February, an Argentine fleet led by Brown engaged the Third Division of the Imperial Navy on the Uruguay River, inflicting heavy casualties against a disorganized Brazilian squadron. The Argentines routed the Third Division, capturing or destroying fifteen Brazilian vessels whilst losing none and frustrating the Brazilian attempt to control the Uruguay river.[25]
Near the coast ofEnsenada in April 7, four Argentine vessels led by Brown slipped out of port in an unsuccessful attempt to surprise a large Brazilian fleet under the command of Norton. Two brigs were sunk, and a schooner was heavily damaged, resulting in a decisive Brazilian victory that ensured the Imperial blockade of the Río de la Plata until thePreliminary Peace Convention of 1828.[26]
The blockade caused serious problems to the export-oriented economy ofBuenos Aires but indirectly contributed to rural provinces such asCórdoba, allowing producers to sell native products to Buenos Aires at an increased price.[27]
The historical English name "River Plate" uses an obsolete sense of the word "plate", which was used extensively as a term for "silver" or "gold" from the 12th century onwards, especially inEarly Modern English.[29] The estuary has been known as theRiver Plate orPlate River in English since at least the time of Francis Drake.[30] This English version of the name served as an inspiration for one of Argentina's most importantfootball clubs,Club Atlético River Plate.
A more literal translation of the name is "Silver River", though this is virtually never used in practice.
^Whigham, Thomas. 2002.The Paraguayan War: Causes and Early Conduct, v. 1. Lincoln, Nebraska: University of Nebraska Press, p. 5.ISBN978-0-8032-4786-4
^e.g., Scheina, Robert L. 2003.Latin America's Wars: The Age of the Caudillo, 1791–1899, v. 1. Dulles, Virginia: Brassey's, Inc., p. 313.ISBN978-1-5748-8450-0
^John/Silva, Harold/Maria Beatriz Nizza da (1992).Nova História da Expansão Portuguesa (direcção de Joel Serrão e A. H. de Oliveira Marques)- O Império Luso-brasileiro (1500-1620), vol. VI. Lisboa: Editorial Presença. pp. 114–170.
Viana, Hélio (1994).História do Brasil: período colonial, monarquia e república (in Portuguese) (15 ed.). São Paulo: Melhoramentos.ISBN978-85-06-01999-3.
