The Rio Paraná along with its tributaries creates a massive watershed that spreads throughout much of the south central part of the continent, essentially encompassing all of Paraguay, much of southern Brazil, northern Argentina, and even reaching into Bolivia. If the Uruguay River is counted as a tributary to the Paraná, this watershed extends to cover much of Uruguay as well. The volume of water flowing into the Atlantic Ocean through the Río de la Plata is roughly equal to the volume at the Mississippi River delta. This watershed services a number of large cities, including São Paulo, Buenos Aires, Asunción and Brasília.
The Paraná and its tributaries are a source of income and even daily sustenance for a number of fishermen who live along its banks; some fish species (such as the surubí and the sábalo) are commercially important and exploited for massive internal consumption or for export.
Much of the length of the Paraná is navigable and is used as an important waterway linking inland cities in Argentina and Paraguay to the ocean, providing deep water ports in many of these cities. The construction of massive hydroelectric dams along the river's length has blocked its use as a shipping corridor to cities further upstream, but the economic impact of those dams is considered to offset this. The Yacyretá and Itaipu dams on the Paraguay border have made the small, largely undeveloped nation the world's largest exporter of hydroelectric power.
Read more about this topic: Paraná River