Iguazu River

The Iguazu River (Portuguese: Rio Iguaçu[2] [ˈʁi.u iɡwaˈsu], Spanish: Río Iguazú [ˈri.o iɣwaˈsu];[3] also called Rio Iguassu[4]) is a river in Brazil and Argentina. It is an important tributary of the Paraná River. The Iguazu River is 1,320 kilometres (820 mi) long, with a drainage basin of 62,000 square kilometres (24,000 sq mi).[5]

Iguaçu, Iguazu rio, Iguassu
The river directly above Iguazu Falls
Map of the Rio de la Plata Basin, showing the Iguazu River joining the Paraná River north of the upper Uruguay River
CountriesBrazil and Argentina
Physical characteristics
SourceSerra do Mar
 • locationNear Curitiba, Paraná, Brazil
 • coordinates25°23′30″S 49°00′11″W / 25.39167°S 49.00306°W / -25.39167; -49.00306
 • elevation1,200 m (3,900 ft)
MouthParaná River
 • location
Foz do Iguaçu, Misiones Province and Paraná, border between Argentina and Brazil
 • coordinates
25°35′33″S 54°35′30″W / 25.59250°S 54.59167°W / -25.59250; -54.59167Coordinates: 25°35′33″S 54°35′30″W / 25.59250°S 54.59167°W / -25.59250; -54.59167[1]
 • elevation
110 m (360 ft)
Length1,320 km (820 mi), East-west
Basin size62,000 km2 (24,000 sq mi)
 • locationIguazu Falls
 • average1,746 m3/s (61,700 cu ft/s)
 • minimum200 m3/s (7,100 cu ft/s)
 • maximum12,799 m3/s (452,000 cu ft/s)
Basin features
River systemParaná River basin
 • leftRio Negro (Iguazu), Rio Xopim
 • rightRio de Areia


The Iguazu originates in the Serra do Mar coastal mountains of the Brazilian state of Paraná and close to Curitiba.[6] For 1,205 kilometres (749 mi), to its confluence with the San Antonio River, the Iguazu flows west through Paraná State, Brazil. Downriver from the confluence the Iguazu River forms the Argentina–Brazil border|boundary between Brazil and Argentina]]'s Misiones Province.[5] Continuing west, the river drops off a plateau, forming Iguazu Falls, which are accessible via the Rainforest Ecological Train. The falls are within national parks in both Brazil, Iguaçu National Park, and Argentina, Iguazú National Park. It empties into the Paraná River at the point where the borders of Argentina, Brazil, and Paraguay join, an area known as the Triple Frontier.


Unlike tropical South American rivers where the annual variations in temperature are relatively limited, the water in the subtropical Iguazu River varies significantly depending on season. At two sites, one located just above and another just below the falls, the water at both varied from about 15.5 to 29 °C (60–84 °F), and average was just below 22 °C (72 °F).[7] The pH is typically near-neutral, ranging from 5.9 to 8.7.[7]

About 100 fish species are native to the Iguazu River and several undescribed species are known.[8][9] Most fish species in the river are catfish, characiforms and cichlids.[9][10] About 70% are endemic, which to a large extent is linked to the falls, serving both as a home for rheophilic species and isolating species above and below.[9][10] This also means that, with the exception of the threatened Steindachneridion melanodermatum in the lower part, large migratory fish known from much of the Paraná River Basin are naturally absent from Iguazu.[8][11] Almost 30 introduced species are found in the river where about one-third originate from other continents (such as carp, largemouth bass, tilapia and African sharptooth catfish) and the remaining from elsewhere in South America (such as dorado, Cichla kelberi, pacu, Brycon hilarii, Prochilodus lineatus and Odontesthes bonariensis).[8][9][12][13]

The unusual Aegla crustacean are locally common in the Iguazu River Basin.[14]

Environmental issuesEdit

In July 2000 more than 4,000,000 litres (1,100,000 US gal) of crude oil spilled into the river from a state-run oil refinery in the municipality of Araucária near Curitiba.[15]

The Iguazu (right) at its confluence with the Paraná (middle)

See alsoEdit


  1. ^ GNS coordinates adjusted using Google Maps and GeoLocator
  2. ^ Rio Iguaçu at GEOnet Names Server
  3. ^ Río Iguazú at GEOnet Names Server
  4. ^ Rio Iguassu at GEOnet Names Server
  5. ^ a b Varis, Olli; Tortajada, Cecilia; Biswas, Asit K. (2008). Management of Transboundary Rivers and Lakes. Springer. p. 271. ISBN 978-3-540-74926-4.
  6. ^ PES Serra da Baitaca (in Portuguese), ISA: Instituto Socioambiental, retrieved 2016-09-20
  7. ^ a b Nardelli, Bueno, Ludwig, and Guimarães (2016). Structure and dynamics of the planktonic diatom community in the Iguassu River, Paraná State, Brazil. Braz. J. Biol. 76(2).
  8. ^ a b c Daga, Debona, Abilhoa, Gubiani & Vitule (2016). Non-native fish invasion of Neotropical ecoregion with high endemism: a review of the Iguaçu River. Aquatic Invasions 11(2): 209-223.
  9. ^ a b c d Baumgartner, Pavanelli, Baumgartner, Bifi, Debona & Frana (2012). Peixes do baixo rio Iguaçu. EDUEM. DOI:10.7476/9788576285861
  10. ^ a b Piálek, Dragová, Casciotta, Almirón & Řičan (2015). Description of two new species of Crenicichla (Teleostei: Cichlidae) from the lower Iguazú River with a taxonomic reappraisal of C. iguassuensis, C. tesay and C. yaha. Historia Natural 5(2): 5-27.
  11. ^ Freshwater Ecoregions of the World (2010): Igussu. Archived 2017-01-16 at the Wayback Machine Retrieved 28 July 2016.
  12. ^ Ferrareze & Nogueira (2015). Impact assessment of the introduction of Cichla kelberi in a large Neotropical reservoir and its lateral lagoons (Upper Paraná River Basin, Brazil). Braz. J. Biol. 75(4).
  13. ^ Gubiani, Frana, Maciel & Baumgartner (2010). Occurrence of the non-native fish Salminus brasiliensis (Cuvier, 1816), in a global biodiversity ecoregion, Iguaçu River, Paraná River basin, Brazil. Aquatic Invasions 5 (2): 223-227.
  14. ^ Cyrino, Bureau & Kapoor, editors (2008). Feeding and Digestive Functions of Fishes. p. 45. Science Publishers. ISBN 978-1-4398-4269-0
  15. ^ "Brazil battles oil spill threat". BBC Online. 18 July 2000. Retrieved 7 June 2012.