Paraguay River

The Paraguay River is South America's fifth-largest river, running through Brazil, Paraguay and Argentina. It serves as part of the Paraguayan border with Argentina as well as with Brazil.

The river's total length is approximately 2,600 km (1,600 mi), from its headwaters south of Diamantino in the Brazilian state of Mato Grasso to its confluence with the Paraná River in Argentina, of which it is the main tributary.

The river flows essentially north to south and divides the country of Paraguay into two distinct halves: the largely uninhabited semi-arid Gran Chaco region to the west and the eastern forested departments where more than 95% of the country's population lives. As such, the river could be considered the key geographical feature of the country with which it shares its name.

_{Paraguay River location map}

Paraguay River Basin

The Paraguay River's drainage basin covers a vast area (over 1,000,000 sq km or 386,000 sq mi) and includes major portions of Paraguay and Argentina, southern Brazil and parts of Bolivia. It is the second major river of the Rio de la Plata Basin, after the Paraná.

Throughout the basin, which covers approximately 1,000,000 sq km (386,000 sq mi), elevations rarely exceed 200 m (650 ft) asl.

The Pantanal, one of the most pristine and biologically rich environments on the planet, is contained within the Upper Paraguay River Basin. It is a huge, gently-sloped basin that receives runoff from the upland areas (the Brazilian Highlands) and slowly releases the water through the Paraguay River and its tributaries.

Each year torrential rains fill the Pantanal's giant basin, creating a vast flooded landscape. When the downpour subsides, water slowly drains into the Paraguay River, leaving behind fish- and snail-filled pools that attract huge flocks of egrets, storks, and spoonbills.

_{Map of the Río de la Plata Basin, showing the Paraguay River joining the Paraná River}