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Ebro
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The Ebro (or Ebre in Catalan. Spanish Ebro pron , Catalan: Ebre, pron or ) is Spain's most voluminous river. Its source is in Fontibre (Cantabria). It flows through cities such as Miranda de Ebro, Logroño, Zaragoza, Flix, Tortosa, and Amposta before discharging in a delta on the Mediterranean Sea in the province of Tarragona.
Romans named this river Iber (Iberus Flumen), hence its current name but probably derives from the greek Hèvros, ?ß???.
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Encyclopedia
The Ebro (or Ebre in Catalan. Spanish Ebro pron , Catalan: Ebre, pron or ) is Spain's most voluminous river. Its source is in Fontibre (Cantabria). It flows through cities such as Miranda de Ebro, Logroño, Zaragoza, Flix, Tortosa, and Amposta before discharging in a delta on the Mediterranean Sea in the province of Tarragona.
Name
The Romans named this river Iber (Iberus Flumen), hence its current name but probably derives from the greek Hèvros, ?ß???. Arguably the whole peninsula and some of the peoples living there were named after the river.
History
In antiquity, The Ebro was used as the dividing line between Roman (north) and Carthaginian (south) expansions after the First Punic War. When Rome, fearful of Hannibal's growing influence in the Iberian Peninsula, made the city of Saguntum (considerably south of the Ebro) a protectorate of Rome, Hannibal viewed this treaty as an aggressive action by Rome and used the event as the catalyst to the Second Punic War.
One of the earliest Cistercian monasteries in Spain, Real Monasterio de Nuestra Senora de Rueda (Royal Monastery of Our Lady of the Wheel), is located on the banks of the Ebro in Aragon. This edifice survives to the present intact, having been established in the year 1202. The monastery is strongly connected to the Ebro, since it used one of the first large waterwheels established in Spain for the production of power. The monastery also diverted flow from the Ebro to create a circulating hydrological central heating system for its buildings.
The river Ebro was the initial starting ground of one of the most famous Republican offensives during the Spanish Civil War, in 1938. The offensive itself, known as the Battle of the Ebro, ended in defeat for the Republican forces, even though they enjoyed initial success in its first stages. However, they were not able to reach the desired objective of Gandesa.
Delta geography
The Ebro delta is one of the largest wetland areas (320 km²) in the western Mediterranean region. The Ebro delta has grown rapidly—the historical rate of growth of the delta is demonstrated by the town of Amposta. This town was a seaport in the 4th Century, and is now located well inland from the current Ebro river mouth. The rounded form of the delta attests to the balance between sediment deposition by the Ebro and removal of this material by wave erosion.
The modern delta is in intensive agricultural use for rice, fruit, and vegetables. The Ebro delta also hosts numerous beaches, marshes, and salt pans that provide habitat for over 300 species of birds. A large part of the delta was designated as in 1983. A network of canals and irrigation ditches constructed by both agricultural and conservation groups are helping to maintain the ecologic and economic resources of the Ebro Delta.
Flow and floods
The Ebro river is the most important river in Spain, 928 km in length and with a drainage basin of 85,550 km². However, the mean annual flow decreased by approximately 29% during the 20th Century due to many causes: the construction of dams, the increasing demands for irrigation and the evaporation (higher than the rainfall, due to low rainfall, high sunshine and strong and dry winds) from reservoirs in the river basins. This situation has a direct impact on the deltaic system at the mouth of the river because its hydrological dynamics are mainly controlled by the river discharge, and the introduction of the salt wedge is favoured by the low tidal range (20 cm) and the diminution on the river discharge. The mean annual river flow is approximately the critical flow which determines the formation and the break-up of the salt wedge. Thus, when the river discharge is between 300 and 400 m³, the salt wedge can occupy the last 5 km of the estuary, but when the discharge is between 100 and 300 m³, the salt wedge can advance up to 18 km from the mouth. For less than 100 m³, the salt wedge quickly advances to its maximum extent, reaching 32 km from the mouth. In addition to decreased mean annual flow, the increased river regulation in the Ebro basin has produced daily and seasonal changes in the flow pattern.
With regards to the sediment load, several authors conclude that the sediment load was reduced by more than 99% during the last century. The drastic reduction in sediment transport implies a sediment deficit in the Delta, which is causing the erosion of the coastline. This erosion together with the sinking of the Delta produced by soil compaction and tectonic subsidence cannot be balanced by the deposition of fluvial sediments, nearly all of them retained in the dams.
River flow in Zaragoza from the end of the nineteenth century:
- March 1888: 3,760 m3/s
- January 1891: 3,250 m³/s
- February 1892: 3,790 m³/s
- January 1895: 3,118 m³/s
- March 1930: 3,600 m³/s
- December 1930: 3,000 m³/s
- October 1937: 3,000 m³/s
- January 1941: 4,000 m³/s
- February 1952: 3,260 m³/s
- January 1961: 4,130 m³/s
- November 1966: 3,154 m³/s
- January 1981: 2,940 m³/s
- February 2003: 2,988 m³/s
- March 2003: 2,220 m³/s
- April 2007: 2,282 m³/s.
The Ebro poured 1,874 hm³ in the river delta from 2007-03-27 to 04-11, with an average of 117 hm³/day .
Ecology
The Ebro Delta Natural Park, with a total surface area of 7,802 ha, was established in 1986 and is of international importance for 8 of its plant species and 69 of its vertebrate fauna. Birdwise it boasts some 95 breeding species, is also very important for a wide range of overwintering species, and in addition serves as an essential stopover point for large numbers of migratory birds. The Ebro delta has the world's largest colony of Audouin's Gulls, which held a record number of more than 15,000 pairs in 2006.
The zebra mussel is an invasive species that is extending upstream in Ebro waters.
See also
External links
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