Río de la Plata
|Río de la Plata|
|River Plate, La Plata River|
NASA photo of the Río de la Plata looking from north to south. Buenos Aires is visible on the right side near the Paraná River delta. River sediments turn the water brown to the vicinity of Montevideo, visible on the left coast.
|Name origin: Spanish, "river of silver"|
|- left||Uruguay River, San Juan River, Santa Lucía River|
|- right||Paraná River, Luján River, Salado River|
|Cities||Buenos Aires, Montevideo, San Fernando, San Isidro, Vicente López, Avellaneda, Hudson, Punta Lara, Atalaya, San Clemente del Tuyú, Ciudad del Plata, Ciudad de la Costa, Colonia del Sacramento, Costa de Oro, Juan Lacaze, Piriápolis|
|Source||confluence of Paraná and Uruguay Rivers|
|- elevation||0 m (0 ft)|
|- location||Argentine Sea, Argentina & Uruguay|
|- elevation||0 m (0 ft)|
|Length||290 km (180 mi)  4,876 km including the Paraná|
|Width||220 km (137 mi) |
|Basin||4,144,000 km2 (1,600,000 sq mi) |
|- average||22,000 m3/s (777,000 cu ft/s) |
Map of the La Plata Basin, showing the Río de la Plata at the mouths of the Paraná and Uruguay rivers, near Buenos Aires.
The Río de la Plata (Spanish pronunciation: [ˈri.o ðe la ˈplata], River of Silver) — usually rendered River Plate in British English and the Commonwealth, and occasionally rendered [La] Plata River in other English-speaking countries — is the estuary formed by the confluence of the Uruguay River and the Paraná River on the border between Argentina and Uruguay. It is a funnel-shaped indentation on the southeastern coastline of South America, about 290 kilometres (180 mi) long.
The Río de la Plata widens from about 2 kilometres (1.2 mi) at the inner part to about 220 kilometres (140 mi) at its mouth. It forms part of the border between Argentina and Uruguay, with the major ports and capital cities of Buenos Aires and Montevideo on its western and northern shores, respectively. The coasts of the Río de la Plata are the most densely populated areas of Argentina and Uruguay.
Some geographers consider the Río de la Plata a gulf or marginal sea of the Atlantic Ocean, while others consider it a river. For those who regard it to be 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).
The Río de la Plata behaves as an estuary in which freshwater and seawater mix. Its freshwater comes from the Paraná River, one of the world's longest, and its main tributary, the Paraguay River, as well as the Uruguay River and other smaller streams. Currents in the Río de la Plata are controlled by tides reaching to its source and beyond, into the Uruguay and Paraná rivers. Both rivers are tidally influenced for about 190 kilometres (120 mi). The tidal ranges in the Río de la Plata are small, but its large width allows for a tidal prism important enough to dominate the flow regime despite the huge discharge received by the tributary rivers. The rivers' discharge is strong enough to prevent salt water from penetrating the inner Río de la Plata.
A submerged shoal, the Barra del Indio, acts as a barrier, dividing the Río de la Plata into an inner freshwater riverine area and an outer brackish estuarine area. The shoal is located approximately between Montevideo and Punta Piedras (the northwest end of Samborombón Bay). It is the freshwater of the inner area that causes many to describe the Río de la Plata as a river. The depth of the inner fluvial zone is between about 1 to 5 metres (3.3 to 16 ft). It is about 180 kilometres (110 mi) long and up to 80 kilometres (50 mi) wide. The depth of the outer estuary zone increases from 5 to 25 metres (16 to 82 ft).
The Río de la Plata is a salt wedge estuary. Saltwater, being denser than freshwater, penetrates into the estuary in a layer below the freshwater, which floats on the surface. Salinity fronts, or haloclines, form at the bottom and on the surface, where fresh and brackish waters meet. The salinity fronts are also pycnoclines due to the water density discontinuities. They play an important role in the reproductive processes of fish species.
Drainage basin 
The Río de la Plata basin is the second largest drainage basin in South America. At a size of about 4,144,000 square kilometres (1,600,000 sq mi), the basin is about one fourth of the continent's surface. It includes areas of southeastern Bolivia, southern and central Brazil, the entire nation of Paraguay, most of Uruguay, and northern Argentina. The main rivers of the La Plata basin are the Paraná, one of the longest in the world, and its main tributary, the Paraguay River, and the Uruguay River.
The Paraná River's main tributaries include the Paranaíba River, Grande River, Corumbá River, Tietê River, Paranapanema river, Iguazu River, Negro River, Carcarañá River, Gualeguay River, and the Salado River. The Paraná River ends in the large Paraná Delta.
The Paraguay's main tributaries include the Jauru River, Cuiabá River, Taquari River, Nabileque River, Curiche Grande River, Apa River, Pilcomayo River, and the Bermejo River. The Paraguay River flows through the Pantanal wetland.
The rivers of the La Plata Basin carry an estimated 57,000,000 cubic metres (2.0×109 cu ft) of silt into the Río de la Plata each year, where the muddy waters are stirred up by winds and tides. The shipping route from the Atlantic to Buenos Aires is kept open by constant dredging.
The Río de la Plata was first explored by the Portuguese in 1513. The Spanish first explored it in 1516, when the Spanish navigator Juan Díaz de Solís traversed it during his search for a passage between the Atlantic and the Pacific Oceans. Juan Díaz de Solís named it the Mar Dulce, or fresh water sea. The Portuguese navigator Ferdinand Magellan briefly explored the estuary in 1520 before his expedition continued its circumnavigation.
Sebastian Cabot made a detailed study of the area and renamed it Río de la Plata. He explored the Paraná and Uruguay rivers between 1526 and 1529. He ascended the Paraná as far as the present-day city of Asunción, and also explored up the Paraguay River. Trading with the Guaraní near today's Asunción, Cabot acquired silver trinkets, and these objects gave rise to the name Río de la Plata, "river of silver".
The first European colony was the city of Buenos Aires, founded by Pedro de Mendoza on 2 February 1536. However, it was quickly abandoned. It was refounded by Juan de Garay on 11 June 1580. The failure to establish a settlement on the estuary led to explorations upriver and the founding of Asunción in 1537.
During the colonial era the Río de la Plata was largely neglected by the Spanish Empire until the 1760s, when Portugal and Britain threatened to expand into the estuary. The Spanish Viceroyalty of the Río de la Plata was created in 1776. In 1806 and 1807 the river was the scene of an important British invasion that aimed to occupy the area.
Conflict in the region intensified after the independence of the former Spanish and Portuguese colonies in the first quarter of the 19th century. Interests on the territories and the navigation rights over the Platine region played a major role in many armed conflicts throughout the century, including the Argentine civil wars, the Cisplatine and Platine wars, and the Paraguayan War. The river was blockaded by extra-regional powers on 1838–1840 and 1845–1850.
Battle of the River Plate 
In the first naval battle in the Second World War the German pocket battleship Admiral Graf Spee was engaged by the Royal Navy (RN) cruisers, HMS Exeter, Ajax and Achilles off the estuary of the River Plate. The German ship retired up the estuary with a crippled fuel system and put into port at Montevideo. A few days later, rather than fight outgunned, she was scuttled in the estuary.
The English name "River Plate" is not, as sometimes thought, a mistranslation, as "plate" was used extensively as a noun for "silver" or "gold" from the 12th century onwards, especially in Early Modern English and the estuary has been known as the River Plate or Plate River in English since at least the time of Francis Drake. A modern translation of the Spanish Río de la Plata is "Silver River", referring not to color but to the riches of the fabled Sierra de la Plata thought to lie upstream.
See also 
- Governorate of the Río de la Plata
- Rioplatense Spanish
- Rio de la Plata Earthquake 1888
- Geography of Uruguay#Topography and hydrography
- The Fontana dei Quattro Fiumi, in Rome's Piazza Navona, contains a figure representing the River Plate.
- Tributaries of the Río de la Plata
- Río Paraná Guazú at GEOnet Names Server (main distributary of the Río Paraná)
- "Limits of Oceans and Seas, 3rd edition". International Hydrographic Organization. 1953. Retrieved 7 February 2010.
- "Río de la Plata". Encyclopædia Britannica. Retrieved 11 August 2010.
- Fossati, Monica; Ismael Piedra-Cueva. "Salinity Simulations of the Rio de la Plata". International Conference on Estuaries and Coasts. Retrieved 11 August 2010.
- Cabreira, A.G.; Madirolas, A.; Alvarez Colombo, G.; Acha, E.M.; Mianzan, H.W. (2006). "Acoustic study of the Río de la Plata estuarine front". ICES Journal of Marine Science 63 (9): 1718–1725. doi:10.1016/j.icesjms.2006.04.026. ISSN 1095-9289. Retrieved 11 August 2010.
- Seeliger, Ulrich; Kjerfve, Björn (2001). Coastal Marine Ecosystems of Latin America. Springer. pp. 185–204. ISBN 978-3-540-67228-9.
- Viana 1994, p. 254.
- Bethell 1987, p. 64.
- Kelsey, Harry (2000). Sir Francis Drake: The Queen's Pirate. Yale University Press. pp. 100–102. ISBN 978-0-300-08463-4.
- (The Achilles was part of the New Zealand Division
- Oxford English Dictionary, 2nd edition, online version.
- Sir Francis Drake’s Famous Voyage Round the World; A Narrative by Francis Pretty, one of Drake's Gentlemen at Arms
- Piola, A. R., R. P. Matano, E. D. Palma, and E. D. Campos (2005): "The influence of the Plata River discharge on the western South Atlantic shelf". Geophysical Research Letters, vol. 32, L01603, doi:10.1029/2004GL021638.
- Real, Walter. España en el Río de la Plata: Descubrimiento y Poblamientos (1516–1588). Montevideo: Club Español. 2001. ISBN 9974-39-317-5.
- Simionato, Claudia G., Vera, Carolina S., Siegismund, Frank (2005). "Surface Wind Variability on Seasonal and Interannual Scales Over Río de la Plata Area" Journal of Coastal Research. 21 (4): 770-783. Abstract online
|Wikimedia Commons has media related to: Río de la Plata|
- Treaty between Uruguay and Argentina concerning the Rio de la Plata and the Corresponding Maritime Boundary (19 November 1973)
- Paraguay, or the Province of the Rio de la Plata, with the Adjacent Regions Tucamen and Santa Cruz de la Sierra is a map from 1616 depicting the area
- "An Account of a Voyage up the River de la Plata, and Thence over Land to Peru: With Observations on the Inhabitants, as Well as Indians and Spaniards, the Cities, Commerce, Fertility, and Riches of That Part of America" from 1698