Paraná

Paraná, river, eastern South America, formed in south central Brazil by the confluence of the Rio Grande and the Paranaíba River. It flows south-west across the eastern edge of the Mato Grosso and then forms the boundary between Brazil and Paraguay. The river sweeps west, forming part of the border between Paraguay and Argentina, to its confluence with the Paraguay River. The Paraná then runs south and east through Argentina until it unites with the Uruguay River to form the River Plate estuary on the Atlantic Ocean. The river is about 3,940 km (2,450 mi) long, of which about 1,610 km (1,000 mi) are navigable by large ships. The Paraná, with its confluent rivers, forms one of the largest drainage systems in South America, with an area of 3.1 million sq km (1.2 million sq mi), second only to that of the Amazon River. The average discharge at its mouth is 17.3 million litres (3.8 million gallons) per second. In its upper reaches the huge Itaipú dam has been built, with a capacity of 12,600 megawatts of hydroelectricity.