Guadiana
Encyclopedia
The Guadiana or Odiana, is an international river located on the Portuguese–Spanish border, separating Extremadura
and Andalucia (Spain) from Alentejo and Algarve (Portugal). The river's basin extends from the eastern portion of Extremadura
to the southern provinces of the Algarve; the river and its tributaries flow from east to west, then south to the border towns of Vila Real de Santo António
(Portugal) and Ayamonte
(Spain), where it flows into the Gulf of Cádiz
. With a course that covers a distance of 829 km, it is the fourth-longest in the Iberian peninsula
, and its hydrological basin extends into an area of approximately 68,000 km² (the majority of which lies within Spain).
The Romans referred to the river as the Anas, from the Latin "Flumen Anas", which means "of/or pertaining to ducks". During the Moorish occupation and settlement, the name was extended and referred to as Uádi Ana (uadi being the Arab
term for river), later passed on to Portuguese and Spanish settlers as the Ouadiana, and later just Odiana. Since the 16th Century, due to Castilian influences, the name has slowly evolved to taken on the form Guadiana, a cognitive variation that developed from many Moorish-Arab river place-names using the prefix guad (such as the rivers Guadalquivir
, Guadalete, Guadalajara
or Guadarrama
).
There is controversy about the exact source of the river in Castilla-La Mancha (see Lagunas de Ruidera
).
The river flows east to west through Spain, then it flows south through Portugal. It flows into the Gulf of Cádiz
, part of the Atlantic Ocean, between Vila Real de Santo António (Portugal) and Ayamonte
(Spain).
municipal term, Ciudad Real Province, Castile-La Mancha
, about 608 meters in altitude.
A classic theory introduced by Pliny the Elder
, was that the river originated from the Lagunas de Ruidera
and divided into two branches: the Upper Guadiana and the Guadiana, while separated by a subterranean course. This legend developed from a misguided belief that the river appeared and disappeared over time (which persisted until the 19th Century) because of its subterranean tributary. In fact, no subterranean course exists, and the belief that the Lagunas de Ruidera
is the source is also controversial. Toponomically and traditionally the Upper Guadiana, which runs from Viveros
(Albacete
) until Argamasilla de Alba
(Ciudad Real
) had been identified as the main branch of the Guadiana. But even hidro-geological characteristics indicate that the Upper Guadiana may not be the principle river within the system.
Another of the origin theories, postulated that the Ciguela and Záncara Rivers were the sources of the Guadiana. Today, they are considered integral parts of the headwaters of the river and important tributaries, but not necessarily the exact origin. The Ciguela's source is in Altos de Cabreras (Cuenca) and pertains to the Sistema Ibérico
(at 1080 meters in altitude). Its course is 225 km long, receiving contributions from the Rivers Jualón, Torrejón, Riánsares, Amarguillo and Záncara
. The union of the Rivers Ciguela and Záncara
permits the replenishment of the waters in the Tablas de Daimiel National Park
, a humid area that was established by the Spanish government in 1973 (situated in the municipalities of Villarrubia de los Ojos
and Daimiel
, in the province of Ciudad Real
).
, where it begins to track south leading to the Gulf of Cádiz
. The Guadiana marks the border of Spain and Portugal twice as it runs to the ocean: first, between the River Caia and Cuncos ravine, then later from the River Chança until its mouth. The river is not used to completely mark the boundary between the two states; between the Olivenza ravine and the Táliga ravine, the border still remains a disputed section claimed de jure
by both countries and administered de facto
by Spain (as part of the Spanish autonomous community
of Extremadura
).
The ecosystem has Mediterranean hydrological characteristics, including high variation in intra- and inter-annual discharge, large floods and severe droughts. This variability is a consequence of considerable variation in rainwater supply, averaged around an annual mean of 400-600mm. The climate is semiarid with an average annual temperature of 14-16 °C.
The river empties into the Gulf of Cadiz
between Ayamonte
and Vila Real de Santo António between the highly touristed regions of the Algarve and sea-side of Andalusia
, forming a saltmarsh estuary
and swamp
. The estuary has a maximum width of 550 metres and its depth ranging from 5 to 17 metres. Tides are semi-diurnal, ranging from 0.8 to 3.5m; their propagation is limited by falls situated 76 km from the mouth at Moinho dos Canais. In the lower estuary there are nature reserves covering a total of 2089ha; in Spain, the Marismas de Isla Cristina and, in Portugal, the Reserva Natural do Sapal de Castro Marim e Vila Real de Santo António (English: Natural Reserve of Castro Marim and Vila Real de Santo António) gives a high nature conservation value to the region.
and Andalusia
) (comprising the provinces of Ciudad Real
, Badajoz
, Huelva
and to a small extent Albacete
) are crossed by the Guadiana. Meanwhile in Portugal the river crosses the regions of Alentejo and Algarve, and the districts of Portalegre, Évora
, Beja
and Faro
.
For the most part, the Guadiana is navigable until Mértola
(a distance of 68 km). There are over thirty dams on the river basin, the largest of which is the Alqueva Dam
, near Moura, in the Beja District, responsible for the largest reservoir in Europe. The Alqueva reservoir, occupies an area of 250 km², with a capacity for 4150 hm³.
Extremadura
Extremadura is an autonomous community of western Spain whose capital city is Mérida. Its component provinces are Cáceres and Badajoz. It is bordered by Portugal to the west...
and Andalucia (Spain) from Alentejo and Algarve (Portugal). The river's basin extends from the eastern portion of Extremadura
Extremadura
Extremadura is an autonomous community of western Spain whose capital city is Mérida. Its component provinces are Cáceres and Badajoz. It is bordered by Portugal to the west...
to the southern provinces of the Algarve; the river and its tributaries flow from east to west, then south to the border towns of Vila Real de Santo António
Vila Real de Santo António (parish)
Vila Real de Santo António is the parish of Vila Real de Santo António Municipality that contains the city of Vila Real de Santo António.It's located in Algarve Region, having a population of nearly 10 000 people, with a density of 1 177,9 hab/km²...
(Portugal) and Ayamonte
Ayamonte
Ayamonte is a town and municipality located in the province of Huelva, Spain. According to the 2005 census, the city has a population of 18,001 inhabitants.-Location and history:...
(Spain), where it flows into the Gulf of Cádiz
Gulf of Cadiz
The Gulf of Cádiz is the arm of the Atlantic Ocean between Cape St. Vincent in Portugal and Cape Trafalgar at the western end of the Strait of Gibraltar...
. With a course that covers a distance of 829 km, it is the fourth-longest in the Iberian peninsula
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...
, and its hydrological basin extends into an area of approximately 68,000 km² (the majority of which lies within Spain).
Etymology
Arab
Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...
term for river), later passed on to Portuguese and Spanish settlers as the Ouadiana, and later just Odiana. Since the 16th Century, due to Castilian influences, the name has slowly evolved to taken on the form Guadiana, a cognitive variation that developed from many Moorish-Arab river place-names using the prefix guad (such as the rivers Guadalquivir
Guadalquivir
The Guadalquivir is the fifth longest river in the Iberian peninsula and the second longest river to be its whole length in Spain. The Guadalquivir is 657 kilometers long and drains an area of about 58,000 square kilometers...
, Guadalete, Guadalajara
Guadalajara
Guadalajara may refer to:In Mexico:*Guadalajara, Jalisco, the capital of the state of Jalisco and second largest city in Mexico**Guadalajara Metropolitan Area*University of Guadalajara, a public university in Guadalajara, Jalisco...
or Guadarrama
Guadarrama
Guadarrama is a town in the Community of Madrid in Spain.Pop: 13032 , approx. 60000 .Co-ordinates . not true...
).
There is controversy about the exact source of the river in Castilla-La Mancha (see Lagunas de Ruidera
Lagunas de Ruidera
The Lagunas de Ruidera are a group of small lakes in the Campo de Montiel, between Albacete Province, and Ciudad Real Province, Spain. Most of the lakes are interconnected and their total water amount may reach 23,06 Hm³, which is considerable by the standards of other lakes in the Iberian...
).
The river flows east to west through Spain, then it flows south through Portugal. It flows into the Gulf of Cádiz
Gulf of Cadiz
The Gulf of Cádiz is the arm of the Atlantic Ocean between Cape St. Vincent in Portugal and Cape Trafalgar at the western end of the Strait of Gibraltar...
, part of the Atlantic Ocean, between Vila Real de Santo António (Portugal) and Ayamonte
Ayamonte
Ayamonte is a town and municipality located in the province of Huelva, Spain. According to the 2005 census, the city has a population of 18,001 inhabitants.-Location and history:...
(Spain).
River Basin
The Guadiana covers a length of 76 kilometres, 818 kilometres of travel distance, of which 578 kilometres are within Spanish territory, 140 kilometres within Portugal, while 100 kilometres are shared between the two nations; 81.9% of its basin is in Spain (55,513 km²) and 17.1% is in Portugal (11,620 km²).Sources
There is some controversy about the exact source of the river in Castilla-La Mancha, but it is generally believed to spring in the Ojos del Guadiana, Villarrubia de los OjosVillarrubia de los Ojos
Villarrubia de los Ojos is a municipality in Ciudad Real, Castile-La Mancha, Spain. According to the 2010 census the municipality has a population of 11,119 inhabitants....
municipal term, Ciudad Real Province, Castile-La Mancha
Castile-La Mancha
Castile-La Mancha is an autonomous community of Spain. Castile-La Mancha is bordered by Castile and León, Madrid, Aragon, Valencia, Murcia, Andalusia, and Extremadura. It is one of the most sparsely populated of Spain's autonomous communities...
, about 608 meters in altitude.
A classic theory introduced by Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
, was that the river originated from the Lagunas de Ruidera
Lagunas de Ruidera
The Lagunas de Ruidera are a group of small lakes in the Campo de Montiel, between Albacete Province, and Ciudad Real Province, Spain. Most of the lakes are interconnected and their total water amount may reach 23,06 Hm³, which is considerable by the standards of other lakes in the Iberian...
and divided into two branches: the Upper Guadiana and the Guadiana, while separated by a subterranean course. This legend developed from a misguided belief that the river appeared and disappeared over time (which persisted until the 19th Century) because of its subterranean tributary. In fact, no subterranean course exists, and the belief that the Lagunas de Ruidera
Lagunas de Ruidera
The Lagunas de Ruidera are a group of small lakes in the Campo de Montiel, between Albacete Province, and Ciudad Real Province, Spain. Most of the lakes are interconnected and their total water amount may reach 23,06 Hm³, which is considerable by the standards of other lakes in the Iberian...
is the source is also controversial. Toponomically and traditionally the Upper Guadiana, which runs from Viveros
Viveros
Viveros is a municipality in Albacete, Castile-La Mancha, Spain. It has a population of 512....
(Albacete
Albacete
Albacete is a city and municipality in southeastern Spain, 258 km southeast of Madrid, the capital of the province of Albacete in the autonomous community of Castile-La Mancha. The municipality had a population of c. 169,700 in 2009....
) until Argamasilla de Alba
Argamasilla de Alba
Argamasilla de Alba is a municipality in Ciudad Real , Castile-La Mancha, Spain. It has a population of 6,791.Cervantes was held prisoner here and refers to the place in the prologue to Don Quixote....
(Ciudad Real
Ciudad Real
Ciudad Real is a city in Castile-La Mancha, Spain, with a population of c. 74,000. It is the capital of the province of Ciudad Real. It has a stop on the AVE high-speed rail line and has begun to grow as a long-distance commuter suburb of Madrid, located 115 miles to the north. A high capacity...
) had been identified as the main branch of the Guadiana. But even hidro-geological characteristics indicate that the Upper Guadiana may not be the principle river within the system.
Another of the origin theories, postulated that the Ciguela and Záncara Rivers were the sources of the Guadiana. Today, they are considered integral parts of the headwaters of the river and important tributaries, but not necessarily the exact origin. The Ciguela's source is in Altos de Cabreras (Cuenca) and pertains to the Sistema Ibérico
Sistema Ibérico
The Sistema Ibérico or Iberian System is one of the main systems of mountain ranges in Spain.It is a vast and complex system of mountain chains and massifs located in the central regions of the Iberian Peninsula, but reaching almost the Mediterranean coast in the Land of Valencia in the east.From...
(at 1080 meters in altitude). Its course is 225 km long, receiving contributions from the Rivers Jualón, Torrejón, Riánsares, Amarguillo and Záncara
Záncara
The Záncara is a 168 km long river in Castile-La Mancha, Spain. It is a tributary to the Cigüela, a tributary of the Guadiana. Its source is near the village Abia de la Obispalía, west of Cuenca, in the Iberian System. The Záncara flows southwest, along the town of Socuéllamos...
. The union of the Rivers Ciguela and Záncara
Záncara
The Záncara is a 168 km long river in Castile-La Mancha, Spain. It is a tributary to the Cigüela, a tributary of the Guadiana. Its source is near the village Abia de la Obispalía, west of Cuenca, in the Iberian System. The Záncara flows southwest, along the town of Socuéllamos...
permits the replenishment of the waters in the Tablas de Daimiel National Park
Tablas de Daimiel National Park
Tablas de Daimiel National Park is a nature reserve in south-central Spain on La Mancha plain in the province of Ciudad Real. It is a wetland in an arid part of Spain. Tablas de Daimiel is the smallest of Spain's fourteen national parks...
, a humid area that was established by the Spanish government in 1973 (situated in the municipalities of Villarrubia de los Ojos
Villarrubia de los Ojos
Villarrubia de los Ojos is a municipality in Ciudad Real, Castile-La Mancha, Spain. According to the 2010 census the municipality has a population of 11,119 inhabitants....
and Daimiel
Daimiel
Daimiel is a municipality in Ciudad Real, Castile-La Mancha, Spain. It has a population of 17,342. The Tablas de Daimiel National Park, a well-known natural reserve, lies partly within the boundaries of the town.-Spanish Civil War:...
, in the province of Ciudad Real
Ciudad Real
Ciudad Real is a city in Castile-La Mancha, Spain, with a population of c. 74,000. It is the capital of the province of Ciudad Real. It has a stop on the AVE high-speed rail line and has begun to grow as a long-distance commuter suburb of Madrid, located 115 miles to the north. A high capacity...
).
Course
From its origin/spring runs from the southern Iberian plain in a direction east to west, to near the town of BadajozBadajoz
Badajoz is the capital of the Province of Badajoz in the autonomous community of Extremadura, Spain, situated close to the Portuguese border, on the left bank of the river Guadiana, and the Madrid–Lisbon railway. The population in 2007 was 145,257....
, where it begins to track south leading to the Gulf of Cádiz
Gulf of Cadiz
The Gulf of Cádiz is the arm of the Atlantic Ocean between Cape St. Vincent in Portugal and Cape Trafalgar at the western end of the Strait of Gibraltar...
. The Guadiana marks the border of Spain and Portugal twice as it runs to the ocean: first, between the River Caia and Cuncos ravine, then later from the River Chança until its mouth. The river is not used to completely mark the boundary between the two states; between the Olivenza ravine and the Táliga ravine, the border still remains a disputed section claimed de jure
De jure
De jure is an expression that means "concerning law", as contrasted with de facto, which means "concerning fact".De jure = 'Legally', De facto = 'In fact'....
by both countries and administered de facto
De facto
De facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...
by Spain (as part of the Spanish autonomous community
Autonomous communities of Spain
An autonomous community In other languages of Spain:*Catalan/Valencian .*Galician .*Basque . The second article of the constitution recognizes the rights of "nationalities and regions" to self-government and declares the "indissoluble unity of the Spanish nation".Political power in Spain is...
of Extremadura
Extremadura
Extremadura is an autonomous community of western Spain whose capital city is Mérida. Its component provinces are Cáceres and Badajoz. It is bordered by Portugal to the west...
).
The ecosystem has Mediterranean hydrological characteristics, including high variation in intra- and inter-annual discharge, large floods and severe droughts. This variability is a consequence of considerable variation in rainwater supply, averaged around an annual mean of 400-600mm. The climate is semiarid with an average annual temperature of 14-16 °C.
The river empties into the Gulf of Cadiz
Gulf of Cadiz
The Gulf of Cádiz is the arm of the Atlantic Ocean between Cape St. Vincent in Portugal and Cape Trafalgar at the western end of the Strait of Gibraltar...
between Ayamonte
Ayamonte
Ayamonte is a town and municipality located in the province of Huelva, Spain. According to the 2005 census, the city has a population of 18,001 inhabitants.-Location and history:...
and Vila Real de Santo António between the highly touristed regions of the Algarve and sea-side of Andalusia
Andalusia
Andalusia is the most populous and the second largest in area of the autonomous communities of Spain. The Andalusian autonomous community is officially recognised as a nationality of Spain. The territory is divided into eight provinces: Huelva, Seville, Cádiz, Córdoba, Málaga, Jaén, Granada and...
, forming a saltmarsh estuary
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
and swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
. The estuary has a maximum width of 550 metres and its depth ranging from 5 to 17 metres. Tides are semi-diurnal, ranging from 0.8 to 3.5m; their propagation is limited by falls situated 76 km from the mouth at Moinho dos Canais. In the lower estuary there are nature reserves covering a total of 2089ha; in Spain, the Marismas de Isla Cristina and, in Portugal, the Reserva Natural do Sapal de Castro Marim e Vila Real de Santo António (English: Natural Reserve of Castro Marim and Vila Real de Santo António) gives a high nature conservation value to the region.
Human impacts
In Spain three autonomous communities, Castilla-La Mancha, ExtremaduraExtremadura
Extremadura is an autonomous community of western Spain whose capital city is Mérida. Its component provinces are Cáceres and Badajoz. It is bordered by Portugal to the west...
and Andalusia
Andalusia
Andalusia is the most populous and the second largest in area of the autonomous communities of Spain. The Andalusian autonomous community is officially recognised as a nationality of Spain. The territory is divided into eight provinces: Huelva, Seville, Cádiz, Córdoba, Málaga, Jaén, Granada and...
) (comprising the provinces of Ciudad Real
Ciudad Real
Ciudad Real is a city in Castile-La Mancha, Spain, with a population of c. 74,000. It is the capital of the province of Ciudad Real. It has a stop on the AVE high-speed rail line and has begun to grow as a long-distance commuter suburb of Madrid, located 115 miles to the north. A high capacity...
, Badajoz
Badajoz
Badajoz is the capital of the Province of Badajoz in the autonomous community of Extremadura, Spain, situated close to the Portuguese border, on the left bank of the river Guadiana, and the Madrid–Lisbon railway. The population in 2007 was 145,257....
, Huelva
Huelva
Huelva is a city in southwestern Spain, the capital of the province of Huelva in the autonomous region of Andalusia. It is located along the Gulf of Cadiz coast, at the confluence of the Odiel and Tinto rivers. According to the 2010 census, the city has a population of 149,410 inhabitants. The...
and to a small extent Albacete
Albacete
Albacete is a city and municipality in southeastern Spain, 258 km southeast of Madrid, the capital of the province of Albacete in the autonomous community of Castile-La Mancha. The municipality had a population of c. 169,700 in 2009....
) are crossed by the Guadiana. Meanwhile in Portugal the river crosses the regions of Alentejo and Algarve, and the districts of Portalegre, Évora
Évora
Évora is a municipality in Portugal. It has total area of with a population of 55,619 inhabitants. It is the seat of the Évora District and capital of the Alentejo region. The municipality is composed of 19 civil parishes, and is located in Évora District....
, Beja
Beja Municipality
Beja Municipality is located Beja District. The city of Beja is located in the municipality.-Parishes:* Albernoa* Baleizão* Salvador* Santa Maria da Feira* Beja Santiago Maio* São João Baptista* Beringel* Cabeça Gorda* Mombeja...
and Faro
Faro, Portugal
Faro is the southernmost city in Portugal. It is located in the Faro Municipality in southern Portugal. The city proper has 41,934 inhabitants and the entire municipality has 58,305. It is the seat of the Faro District and capital of the Algarve region...
.
For the most part, the Guadiana is navigable until Mértola
Mértola
Mértola is a municipality in southeastern Portugal next to the Spanish border. It has a total area of 1,292.87 km² and a total population of 8,712 inhabitants . In terms of land area, it is the sixth-largest municipality in Portugal. The resultant population density of 6.74 persons/km² is the...
(a distance of 68 km). There are over thirty dams on the river basin, the largest of which is the Alqueva Dam
Alqueva dam
The Alqueva dam is a dam located on the Guadiana River in the Alentejo region. The reservoir is the largest in Portugal and Western Europe.The complex project was made to produce hydroelectric power, irrigation for farms in the surrounding area, as well as a large reservoir where several tourist...
, near Moura, in the Beja District, responsible for the largest reservoir in Europe. The Alqueva reservoir, occupies an area of 250 km², with a capacity for 4150 hm³.