The Rio de la Plata (Spanish pronunciation: ['ri.o de la 'plata], River of Silver) -- rendered River Plate in British English and the Commonwealth and La Plata River (occasionally Plata River) in other English-speaking countries -- is the estuary formed by the confluence of the Uruguay and the Parana rivers. It forms a funnel-shaped indentation on the southeastern coastline of South America, about 290 kilometres (180 mi) long.
The Rio 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 Rio de la Plata are the most densely populated areas of Argentina and Uruguay.In its waters took place the first naval battle in the Second World War and the first one of Battle of the Atlantic, the Battle of the River Plate.


== GeographyEdit ==

Some geographers consider the Rio 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 Rio de la Plata behaves as an estuary in which freshwater and seawater mix. Its freshwater comes from the Parana River, one of the world's longest and the Rio's main tributary, as well as from the Uruguay River and other smaller streams. Currents in the Rio de la Plata are controlled by tides reaching to its source and beyond, into the Uruguay and Parana rivers. Both rivers are tidally influenced for about 190 kilometres (120 mi). The tidal ranges in the Rio 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 Rio de la Plata.
A submerged shoal, the Barra del Indio, acts as a barrier, dividing the Rio 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 Samborombon Bay). It is the freshwater of the inner area that causes many to describe the Rio de la Plata as a river. The depth of the inner fluvial zone is between about 1 to 5 metres (3.3 to 16.4 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 Rio 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.


=== ExtentEdit ===
The International Hydrographic Organization defines the eastern extent of the Rio de la Plata as "A line joining Punta del Este, Uruguay (34deg58.5'S 54deg57.5'W) and Cabo San Antonio, Argentina (36deg18'S 56deg46'W)".
The western limit is on the confluence of the Uruguay River at Punta Gorda, Colonia.


== Drainage basinEdit ==

The Rio de la Plata basin is the second largest drainage basin in South America. At a size of about 3,170,000 square kilometres (1,220,000 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 Parana, one of the longest in the world, and its main tributary, the Paraguay River, and the Uruguay River.
The Parana River's main tributaries include the Paranaiba River, Grande River, Corumba River, Tiete River, Paranapanema River, Iguazu River, Negro River, Carcarana River, Gualeguay River, and the Salado River. The Parana River ends in the large Parana Delta.
The Paraguay's main tributaries include the Jauru River, Cuiaba 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 Uruguay's main tributaries include the Pelotas River, Canoas River, Peperiguacu River, Ibicui River, Quarai River, and the Rio Negro.
The rivers of the La Plata Basin carry an estimated 57,000,000 cubic metres (2.0x109 cu ft) of silt into the Rio 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.


== HistoryEdit ==

The Rio de la Plata was first explored by the Portuguese in 1512-1513. The Spanish first explored it in 1516, when the navigator Juan Diaz de Solis traversed it during his search for a passage between the Atlantic and the Pacific Oceans, naming 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, and in 1521 Cristovao Jacques also explored the Plate River estuary and ascended for the first time the Parana River, entering it for about 23 leagues (around 140 km), to near the present city of Rosario.
Sebastian Cabot made a detailed study of the area and renamed it Rio de la Plata. He explored the Parana and Uruguay rivers between 1526 and 1529. He ascended the Parana as far as the present-day city of Asuncion, and also explored up the Paraguay River. Trading with the Guarani near today's Asuncion, Cabot acquired silver trinkets, and these objects gave rise to the name Rio de la Plata, "river of silver".
The area was visited by Francis Drake's fleet in early 1578, in the early stages of his circumnavigation.
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 Asuncion in 1537.
During the colonial era the Rio 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 Rio 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 in 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 1838-1840 and 1845-1850.


== Battle of the River PlateEdit ==

In the first naval battle of 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.


== EtymologyEdit ==
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 Rio 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.
The English version of the name served as an inspiration for one of Argentina's most important football clubs, Club Atletico River Plate.


== FaunaEdit ==
The Rio de la Plata is a habitat for the Loggerhead Sea Turtle, Green Sea Turtle, Leatherback Sea Turtle, the rare La Plata Dolphin, and many species of fish.


== See alsoEdit ==
Argentina-Uruguay relations
Geography of Uruguay#Topography and hydrography
The Fontana dei Quattro Fiumi, in Rome's Piazza Navona, contains a figure representing the River Plate.
Governorate of the Rio de la Plata
Martin Garcia canal dispute
Rioplatense Spanish
Rio de la Plata Earthquake 1888
Tributaries of the Rio de la Plata


== ReferencesEdit ==


== BibliographyEdit ==