São Francisco River

"Sao Francisco" redirects here. For other uses, seeSão Francisco.

TheSão Francisco River(Portuguese:Rio São Francisco,Portuguese pronunciation:[sɐ̃wfɾɐ̃ˈsisku]) is a largeriverinBrazil.With a length of 2,914 kilometres (1,811 mi),it is the longest river that runs entirely in Brazilian territory, and the fourth longest inSouth Americaand overall in Brazil (after theAmazon,theParanáand theMadeira). It used to be known as theOparaby the indigenous people before colonisation, and is today also known as"Velho Chico".

São Francisco River Velho Chico
São Francisco river basin
Native name	Rio São Francisco(Portuguese)
Location
Country	Brazil
States	Minas Gerais,Bahia,Pernambuco,Alagoas,Sergipe
Region	South America
Physical characteristics
Source	Canastra Mountains
• location	São Roque de Minas,Minas Gerais
• coordinates	20°13′49″S46°26′35″W
• elevation	1,450 m (4,760 ft)
Mouth	Atlantic Ocean
• location	nearPiaçabuçu,Alagoas / Sergipe border
• coordinates	10°29′59″S36°23′44″W
• elevation	0 m (0 ft)
Length	2,830 km (1,760 mi)
Basin size	641,000 km2(247,000 sq mi)
Discharge
• average	2,943 m3/s (103,900 cu ft/s)
• minimum	1,480 m3/s (52,000 cu ft/s)
• maximum	11,718 m3/s (413,800 cu ft/s)

The São Francisco originates in theCanastramountain range in the central-western part of the state ofMinas Gerais.It runs generally north in the states of Minas Gerais andBahia,behind the coastal range, draining an area of over 630,000 square kilometres (240,000 sq mi), before turning east to form the border between Bahia on the right bank and the states ofPernambucoandAlagoason the left one. After that, it ends on the boundaries between the states ofAlagoasandSergipeand washes into theAtlantic Ocean.In addition to the five states which the São Francisco directly traverses or borders, itsdrainage basinalso includes tributaries from the state ofGoiásand theFederal District.

It is an important river for Brazil, called "the river of national integration" because it unites diverse climates and regions of the country, in particular the Southeast with the Northeast. It is also significant because it passes through thesemi-arid regionof the country, a region historically characterized by droughts and low access to water. It isnavigablebetween the cities ofPirapora(Minas Gerais) andJuazeiro(Bahia), as well as betweenPiranhas(Alagoas) and the mouth on the ocean, but traditional passenger navigation has almost disappeared in recent years due to changes in the river flow (see below).

Names

The river is named forSaint Francis of Assisi,from its first discovery byEuropeanson hisfeast day(4 October) in 1501. The nickname "Velho Chico" may be translated as "Old Frank":velhomeans old, andchicois adiminutiveof Francisco, itself the Portuguese form of the name Francis.

Indigenous peoplescalled itKaleshíin the now extinctTuxá language,andOpárain the extinctNatú language.

History

See also:Trans–São Francisco languages

Tuxá,Truká,Natú,Kariri languages,easternMaxakalían languages,Jê languages,andvarious unclassified extinct languageswere spoken in the São Francisco River basin.

TheItalianexplorerAmerigo Vespuccifirst saw the river on 4 October 1501. In 1865 theBritishexplorer and diplomatRichard Francis Burtonwas transferred toSantosinBrazil.He explored thecentral highlands,canoeing down the São Francisco river from its source to the falls ofPaulo Afonso.

Sections

River source

São Francisco River south of Paulo Afonso

84 m high bridge over the São Francisco between the states of Bahia and Alagoas

The course of the river, running through five states, may be divided into four sections, as follows:

1. The high part, from its source toPiraporain Minas Gerais
2. The upper middle part, from Pirapora, where the navigable part begins, up toRemanso(Bahia) and theSobradinho Dam
3. The lower middle part, from the Sobradinho dam toPaulo Afonso,also in Bahia (bordering on Alagoas), and ending at theItaparica Dam
4. The low part, from Paulo Afonso to the river's mouth on theAtlantic Ocean

Tributaries

The river obtains water from 168 rivers and streams, of which 90 are on the right bank and 78 on the left bank. The maintributariesare:

• Paraopeba River
• Abaeté River
• Das Velhas River
• Jequitaí River
• Paracatu River
• Urucuia River
• Verde Grande River
• Carinhanha River
• Corrente River
• Grande River

Navigability

A river canyon on the São Francisco river.

The São Francisco is naturally navigable all through the year betweenPirapora(Minas Gerais) and the twin cities ofPetrolina(Pernambuco) andJuazeiro(Bahia), a length of 1,371 kilometres (852 mi). However, there are large variations in depth depending on the rainfall. Because of the diversity of physical characteristics over the course of the navigable stretch, it may be divided into three substretches, as follows:

• From Pirapora toPilão Arcado(Bahia), a length of 1,015 kilometres (631 mi); differences in height up to 6 metres (20 ft) may occur due to rains and drought.
• From Pilão Arcado to theSobradinho Dam;the latter's reservoir is 314 kilometres (195 mi) long, with a surface area of 4,214 square kilometres (1,627 sq mi) and a comfortable depth.
• From the Sobradinho dam toPetrolina/Juazeiro,with a length of 42 kilometres (26 mi) and an average depth of 2 metres (6 ft 7 in), sustained by a flow of 1,500 m³/s (53,000 cu ft/s).

Until recent years, the São Francisco was regularly navigated by a type of passenger boat calledgaiola(Portuguese for "cage" ). These were paddle-wheel steamboats, some of them having beenMississippiriverboatsand dating from the time of theAmerican Civil War.After the Sobradinho dam was built in Bahia, the conditions of navigability were altered considerably, since the reservoir's large size allowed for the formation of short waves of considerable height. Although the dam has a navigationlock,the waves and currents made traversing the lake difficult for thegaiolas.At the same time, deforestation and excessive agricultural use of the upper-course waters of the São Francisco and its tributaries greatly reduced the water flow in the middle course, creating sand banks and islands that hindered navigation.

In a short time, conditions were such that navigation became impossible for the largegaiolas,although still possible for smaller boats. The shells of those old riverboats can still be seen on the river at Pirapora. As of 2009, a single boat, theBenjamim Guimarães,remains in activity, making short-distance tourist cruises from Pirapora toSão Romãoand back.

Fish

Two of the fish that areendemicto the river basin:Lophiosilurus alexandriandHypsolebias magnificus

More than 200 fish species are known from the São Francisco River basin and it is expected that several additional species will be discovered in the future, especially from the relatively poorly known upper parts of the river.About 10% of the fish species known from the river basin arethreatenedand about 13% are important in fisheries.About 64% of the fish species known from the basin areendemic,includingConorhynchos conirostris(a catfish of uncertaintaxonomicaffinities),Lophiosilurus alexandri(a flattened catfish),Franciscodoras marmoratus(an armoured catfish),Pygocentrus piraya(the largest species of piranha),Orthospinus franciscensis(a characin and the only member of its genus),Hasemania nana(a small tetra that often is kept in aquariums),andSalminus franciscanus(a relative of thegolden dorado).More than 40 annualkillifishspecies are found in the São Francisco River basin, especially from the generaCynolebiasandHypsolebias.Dams (preventingfish migrationson the river) and pollution do present a problem to the species in the river, and fish mass deaths have been recorded.

Towns and population

São Francisco River, inIbotirama,BA, Brazil

Mouth of the São Francisco river

The area crossed by the river is vast and sparsely populated, but several towns lie on the river. Beginning in Minas Gerais, the river passes byPirapora,São Francisco,Januária,Bom Jesus da Lapa,the twin cities ofPetrolinaandJuazeiro,andPaulo Afonso.The hinterland is arid and underpopulated, so most of the towns are small and isolated. Only Petrolina and Juazeiro have grown into medium-sized cities and have become prosperous because of fruit production based on irrigation.

Hydroelectric dams

The river's hydroelectric potential started being harnessed in 1955, when thePaulo Afonso damwas built between Bahia and Alagoas. The Paulo Afonso plant now provides electric power for the whole of Northeastern Brazil. Four other large hydroelectric plants were later built:Três Mariasin Minas Gerais, built in 1961,Sobradinhoin Bahia, built in 1977,Luiz Gonzaga (Itaparica),between Bahia and Pernambuco, in 1988 and theXingónearPiranhasin 1994. The Sobradinho reservoir is one of the largest artificial lakes in the world, with an area of 4,214 square kilometres (1,627 sq mi).

The section of dramatic canyons between the Paulo Afonso and Xingó dams, including part of the Xingó reservoir, is protected by the 26,736 hectares (66,070 acres)Rio São Francisco Natural Monument.

Cultural significance

The São Francisco has great importance in history and particularly in folklore. That history is celebrated in song, legend and souvenirs based on thecarrancas,a kind ofgargoyleplaced on the prow of thegaiolaboats and intended to scare away river demons from the boat. Tourist shops far from the river have modernized replicas and miniatures of the vanishing originals. The stories of river demons and monsters persist today.

From Paulo Afonso to the historic town ofPenedo(Alagoas), the river lies at the bottom of a gorge or steep sided valley.Piranhas,a nearby town, was once the terminus of a railroad. The town has a number of abandoned historical buildings from that period. They have been restored and are emerging as a tourist attraction.

Controversial diversion project (under construction)

In 2005, the Brazilian government proposed a controversial water diversion project that will bring water from the river to semiarid areas of four Brazilian states (Ceará, Pernambuco, Paraíba and Rio Grande do Norte). Environmentalists argue that the project will do more harm than good, benefitting only large landowners and a very small population, while bringing considerable ecological impact. The government insists that the project will give the people in the four states a much-needed water supply.

The diversion project intake point is located atCabrobó.

External links

• Main Brazilian Hydrographic Basins Map and brief description
• Organization of American States' document on the river
• Course of the São Francisco River and the Navigation Along It from São Paulo to the Pitangui Minesis a map from 1700(in French and English)