Ebro
Encyclopedia
The Ebro (ˈeβɾo) or Ebre (ˈeβɾəˈeβɾe) is one of the most important rivers in the Iberian Peninsula
. It is the biggest river by discharge volume in Spain.
The Ebro flows through the following cities:
Its source is in Fontibre
(Cantabria
), from the Latin words Fontes Iberis, source of the Ebro. The upper Ebro rushes through rocky gorges in Burgos Province. Flowing roughly eastwards it begins forming a wider river valley when it reaches Navarre
and La Rioja thanks to many tributaries flowing down from the Iberian System
on one side, and the Navarre mountains and the western Pyrenees
, on the other.
The valley expands and the Ebro's flow then becomes slower as its water volume increases flowing across Aragon
. There, massive tributaries flowing from the Central Pyrenees and the Iberian System discharge large amounts of water, especially in spring during the thawing season of the mountain snow. As it flows through Zaragoza
the Ebro, emblematic river of Aragon, is already a sizeable river. The Basilica of Our Lady of the Pillar
stands next to the Ebro.
After reaching Catalonia the Ebro Valley narrows and the river becomes constrained by mountain ranges, making wide bends. Massive dams have been built in this area, like the dams at Mequinensa, Riba-roja
, Flix
. In the final section of its course it bends southwards and flows through spectacular gorges. The massive calcareous cliffs of the Serra de Cardó range constrain the river during this last stretch, separating the Ebro Valley from the Mediterranean coastal area. After passing the gorges, the Ebro bends again eastwards near Tortosa
before discharging in a delta
on the Mediterranean close to Amposta
in the province of Tarragona
.
The Ebro Delta
(in Catalan: Delta de l'Ebre), in the Province of Tarragona, Catalonia
, is one of the largest wetland
areas (320 km²) in the western Mediterranean region. The Ebro delta has expanded rapidly on soils washed downriver—the historical rate of growth of the delta is demonstrated by the town of Amposta
. A seaport
in the 4th century, it 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
(in particular citrus), and vegetable
s. The Ebro delta also has numerous beach
es, marsh
es, and salt pan
s that provide habitat for over 300 species of birds. In 1983 Spain designated a large part of the delta as Ebro Delta Natural Park (Parc Natural del Delta de l'Ebre) to protect the natural resources. 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.
named this river Iber (Iberus Flumen), hence its current name. Arguably the whole peninsula
and some of the peoples living there
were named after the river.
, the Ebro was used as the dividing line between Roman
(north) and Carthaginian
(south) expansions after the First Punic War
(264-241 BC). 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 the 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 Señora de Rueda
(Royal Monastery of Our Lady of the Wheel), is located on the banks of the Ebro in Aragon
. Established in AD 1202, the edifice survives intact. The monastery is strongly connected to the Ebro, since it used one of the first large waterwheels built for the production of power in Spain. The monastery also diverted flow from the Ebro to create a circulating, hydrological central heating system for its buildings.
The river Ebro in 1938 was the starting ground of one of the most famous Republican
offensives of the Spanish Civil War
. Known as the Battle of the Ebro
, the offensive ended in defeat for the Republican forces, although they enjoyed success in its first stages. They were not able to reach their objective of Gandesa
.
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.
The decrease in river discharge has meant introduction of the salt wedge further into the river. 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 which are retained behind the dams.
River flow in Zaragoza
from the end of the nineteenth century:
The Ebro poured 1,874 hm³ in the river delta
from 2007-03-27 to 04-11, with an average of 117 hm³/day .
birds. The Ebro delta has the world's largest colony of Audouin's Gull
s. In 2006 it held a record number of more than 15,000 pairs.
There are concerns about the ecological impact of introduction of foreign species
that is almost always a burden, affecting much of the original ecosystem
introduced species rapidly caused the extinction
of numerous indigenous species. The introduction of American crayfish Procambarus clarkii
has resulted in economic losses, introduced elsewhere for cultivation, its success is attributable to its ability to colonise disturbed habitats that would be unsuitable for the edible iberian crayfish
. The semiacuatic rodent Myocastor coypus or nutria is presuming to expand in some northwest tributaries of the head damaging crops and protected national parks in Basque Country
.
The zebra mussel
, an invasive species
, is expanding upstream in Ebro waters. Due to its rapid rate of reproduction, the species adversely affects the port underwater machinery as well as that of dams and hydroelectric plants, in addition to competing with native species. Following the introduction of Wels catfish
are fishes whose number is in clear and rapid decline. Since its introduction in the reservoir Mequinenza in 1974 - has spread to other parts of the Ebro basin over Ebro and its tributaries, especially river Segre. Some endemics species of iberian barbels, genus Barbus
in the Cyprinidae, having once been abundant especially in the Ebro river. Competition and predation by Wels catfish
has caused its complete disappearance in the middle channel Ebro around 1990. The ecology of the river also, has now a major development in the amount of aquatic vegetation, seaweed and algae. Barbel species from mountain stream tributary of the Ebro that Wels catfish
has not colonized, were not affected.
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...
. It is the biggest river by discharge volume in Spain.
The Ebro flows through the following cities:
- ReinosaReinosaReinosa is a municipality in Cantabria, Spain. , it has 10,307 inhabitants.-External links:* * - Cantabria 102 Municipios...
in CantabriaCantabriaCantabria is a Spanish historical region and autonomous community with Santander as its capital city. It is bordered on the east by the Basque Autonomous Community , on the south by Castile and León , on the west by the Principality of Asturias, and on the north by the Cantabrian Sea.Cantabria...
. - Miranda de EbroMiranda de EbroMiranda de Ebro is a city on the Ebro river in the province of Burgos in the autonomous community of Castile and León, Spain. It is located in the north-eastern part of the province, on the border with the province of Álava and the autonomous community of La Rioja...
in Castile and LeónCastile and LeónCastile and León is an autonomous community in north-western Spain. It was so constituted in 1983 and it comprises the historical regions of León and Old Castile...
. - HaroHaro, La RiojaHaro is a town and municipality in the northwest of La Rioja province in northern Spain. It is known for its fine red wine and every year the Haro Wine Festival is held where locals hold a wine battle....
, LogroñoLogroñoLogroño is a city in northern Spain, on the Ebro River. It is the capital of the autonomous community of La Rioja, formerly known as La Rioja Province.The population of Logroño in 2008 was 153,736 and a metropolitan population of nearly 197,000 inhabitants...
, CalahorraCalahorraCalahorra, , La Rioja, Spain is a municipality in the comarca of Rioja Baja, near the border with Navarre on the right bank of the Ebro. During ancient Roman times, Calahorra was a municipium known as Calagurris.-Location:...
and AlfaroAlfaro, La RiojaAlfaro is a town and municipality in La Rioja, northern Spain. Its population at January 2009 was of 9,883 inhabitants and has 194.23 km² extension...
in La RiojaLa Rioja (Spain)La Rioja is an autonomous community and a province of northern Spain. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, and Nájera.-History:...
. - TudelaTudela, NavarreTudela is a municipality in Spain, the second city of the autonomous community of Navarre. Its population is around 35,000. Tudela is sited in the Ebro valley. Fast trains running on two-track electrified railways serve the city and two freeways join close to it...
in NavarreNavarreNavarre , officially the Chartered Community of Navarre is an autonomous community in northern Spain, bordering the Basque Country, La Rioja, and Aragon in Spain and Aquitaine in France... - AlagónAlagón, ZaragozaAlagón is a municipality located in the province of Zaragoza, Aragon, Spain. According to the 2009 census , the municipality has a population of 7195 inhabitants.-See also:*List of municipalities in Zaragoza...
, UteboUteboUtebo is a municipality located in the province of Zaragoza, Aragon, Spain. According to the 2010 census , the municipality has a population of 17,999 inhabitants....
, ZaragozaZaragozaZaragoza , also called Saragossa in English, is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain...
and CaspeCaspeCaspe or Casp is a historic town and municipality in the province of Zaragoza, in the autonomous community of Aragon, Spain. It is situated some 100 km to the east of the provincial capital, Zaragoza.-History:...
in AragonAragonAragon is a modern autonomous community in Spain, coextensive with the medieval Kingdom of Aragon. Located in northeastern Spain, the Aragonese autonomous community comprises three provinces : Huesca, Zaragoza, and Teruel. Its capital is Zaragoza... - FlixFlixFlix is a town in the comarca of Ribera d'Ebre, Catalonia. Situated on a promontory by the Ebre river, the town occupied an important strategic position...
, Móra d'EbreMóra d'EbreMóra d'Ebre is the capital of the comarca of the Ribera d'Ebre in Catalonia,Spain. It is situated on the right bank of the Ebre river in the Móra Hollow, and is served by the N-420 roadto Reus and Gandesa, the N-230 road to Lleida...
, BenifalletBenifalletBenifallet is a municipality in the comarca of Baix Ebre, in the province of Tarragona, in Catalonia, Spain.This town is located by the Ebro River, below the Cardó Massif. It is popular among kayakers who make trips down the final Ebro Gorges....
, TivenysTivenysTivenys is a municipality in the comarca of the Baix Ebre in Catalonia. It's situated on the left bank of the Ebre river.-External links :* * *...
, XertaXertaXerta is a town and municipality of the comarca of Baix Ebre. Is established in a sharp bend to the right of the river Ebre, about 12 km upstream from the city of Tortosa in province of Tarragona, Catalonia, Spain.- Geographical context :...
, AldoverAldoverAldover is a municipality in the comarca of Baix Ebre, in the province of Tarragona, in Catalonia, Spain.There was a RENFE railway line from Tortosa to Alcañiz and Zaragoza that used to pass through this town until 1973...
, TortosaTortosa-External links:* *** * * *...
, and AmpostaAmpostaAmposta is the capital of the comarca of Montsià, in the province of Tarragona, Catalonia, Spain.It is located at 8 metres above the sea, by the Ebre river, not far from its end. Population 18,841 ....
in Catalonia.
Geography
Fontibre
Fontibre is a locality of the municipality Hermandad de Campoo de Suso, in Cantabria. It is located 3 km from Reinosa.The source of the Ebro River is located in Fontibre. In fact, this name derives from the Latin words Fontes Iberis, source of the Ebro....
(Cantabria
Cantabria
Cantabria is a Spanish historical region and autonomous community with Santander as its capital city. It is bordered on the east by the Basque Autonomous Community , on the south by Castile and León , on the west by the Principality of Asturias, and on the north by the Cantabrian Sea.Cantabria...
), from the Latin words Fontes Iberis, source of the Ebro. The upper Ebro rushes through rocky gorges in Burgos Province. Flowing roughly eastwards it begins forming a wider river valley when it reaches Navarre
Navarre
Navarre , officially the Chartered Community of Navarre is an autonomous community in northern Spain, bordering the Basque Country, La Rioja, and Aragon in Spain and Aquitaine in France...
and La Rioja thanks to many tributaries flowing down from the Iberian System
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...
on one side, and the Navarre mountains and the western Pyrenees
Pyrenees
The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain...
, on the other.
Aragon
Aragon is a modern autonomous community in Spain, coextensive with the medieval Kingdom of Aragon. Located in northeastern Spain, the Aragonese autonomous community comprises three provinces : Huesca, Zaragoza, and Teruel. Its capital is Zaragoza...
. There, massive tributaries flowing from the Central Pyrenees and the Iberian System discharge large amounts of water, especially in spring during the thawing season of the mountain snow. As it flows through Zaragoza
Zaragoza
Zaragoza , also called Saragossa in English, is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain...
the Ebro, emblematic river of Aragon, is already a sizeable river. The Basilica of Our Lady of the Pillar
Basilica of Our Lady of the Pillar
The Basilica-Cathedral of Our Lady of the Pillar is a Roman Catholic church in the city of Zaragoza, Aragon, Spain. The Basilica venerates Blessed Virgin Mary, under her title Our Lady of the Pillar praised as Mother of the Hispanic Peoples by Pope John Paul II...
stands next to the Ebro.
After reaching Catalonia the Ebro Valley narrows and the river becomes constrained by mountain ranges, making wide bends. Massive dams have been built in this area, like the dams at Mequinensa, Riba-roja
Riba-roja d'Ebre
Riba-roja d'Ebre is a municipality in the comarca of the Ribera d'Ebre in southern Catalonia, Spain. It is the site of a large hydroelectric power station, on the Ebro river...
, Flix
Flix
Flix is a town in the comarca of Ribera d'Ebre, Catalonia. Situated on a promontory by the Ebre river, the town occupied an important strategic position...
. In the final section of its course it bends southwards and flows through spectacular gorges. The massive calcareous cliffs of the Serra de Cardó range constrain the river during this last stretch, separating the Ebro Valley from the Mediterranean coastal area. After passing the gorges, the Ebro bends again eastwards near Tortosa
Tortosa
-External links:* *** * * *...
before discharging in a delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
on the Mediterranean close to Amposta
Amposta
Amposta is the capital of the comarca of Montsià, in the province of Tarragona, Catalonia, Spain.It is located at 8 metres above the sea, by the Ebre river, not far from its end. Population 18,841 ....
in the province of Tarragona
Tarragona (province)
Tarragona is a province of eastern Spain, in the southern part of the autonomous community of Catalonia. It is bordered by the provinces of Castellón, Teruel, Zaragoza, Lleida, Barcelona, and the Mediterranean Sea....
.
Delta geography
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
(in Catalan: Delta de l'Ebre), in the Province of Tarragona, Catalonia
Catalonia
Catalonia is an autonomous community in northeastern Spain, with the official status of a "nationality" of Spain. Catalonia comprises four provinces: Barcelona, Girona, Lleida, and Tarragona. Its capital and largest city is Barcelona. Catalonia covers an area of 32,114 km² and has an...
, is one of the largest wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
areas (320 km²) in the western Mediterranean region. The Ebro delta has expanded rapidly on soils washed downriver—the historical rate of growth of the delta is demonstrated by the town of Amposta
Amposta
Amposta is the capital of the comarca of Montsià, in the province of Tarragona, Catalonia, Spain.It is located at 8 metres above the sea, by the Ebre river, not far from its end. Population 18,841 ....
. A seaport
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
in the 4th century, it is now located well inland from the current Ebro river mouth. The rounded form of the delta attests to the balance between sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
deposition by the Ebro and removal of this material by wave erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.
The modern delta is in intensive agricultural
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
use for rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
, fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
(in particular citrus), and vegetable
Vegetable
The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....
s. The Ebro delta also has numerous beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es, marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
es, and salt pan
Dry lake
Dry lakes are ephemeral lakebeds, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts. Dry lakes are also referred to as alkali flats, sabkhas, playas or mud flats...
s that provide habitat for over 300 species of birds. In 1983 Spain designated a large part of the delta as Ebro Delta Natural Park (Parc Natural del Delta de l'Ebre) to protect the natural resources. 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.
Name
The RomansAncient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
named this river Iber (Iberus Flumen), hence its current name. Arguably the whole 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 some of the peoples living there
Iberians
The Iberians were a set of peoples that Greek and Roman sources identified with that name in the eastern and southern coasts of the Iberian peninsula at least from the 6th century BC...
were named after the river.
History
In antiquityClassical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...
, the Ebro was used as the dividing line between Roman
Roman Republic
The Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...
(north) and Carthaginian
Carthaginian Republic
Ancient Carthage was a civilization centered on the Phoenician city-state of Carthage, located in North Africa on the Gulf of Tunis, outside what is now Tunis, Tunisia. It was founded in 814 BC...
(south) expansions after the First Punic War
First Punic War
The First Punic War was the first of three wars fought between Ancient Carthage and the Roman Republic. For 23 years, the two powers struggled for supremacy in the western Mediterranean Sea, primarily on the Mediterranean island of Sicily and its surrounding waters but also to a lesser extent in...
(264-241 BC). When Rome
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
, 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 the treaty as an aggressive action by Rome and used the event as the catalyst to the Second Punic War
Second Punic War
The Second Punic War, also referred to as The Hannibalic War and The War Against Hannibal, lasted from 218 to 201 BC and involved combatants in the western and eastern Mediterranean. This was the second major war between Carthage and the Roman Republic, with the participation of the Berbers on...
.
One of the earliest Cistercian monasteries
Monastery
Monastery denotes the building, or complex of buildings, that houses a room reserved for prayer as well as the domestic quarters and workplace of monastics, whether monks or nuns, and whether living in community or alone .Monasteries may vary greatly in size – a small dwelling accommodating only...
in Spain, Real Monasterio de Nuestra Señora de Rueda
Real Monasterio de Nuestra Senora de Rueda
Rueda Abbey or Rueda de Ebro Abbey is a former Cistercian monastery in Sástago in the Ribera Baja del Ebro comarca, province of Zaragoza, Aragon, Spain, 74 kilometres to the south-east of Zaragoza on the left bank of the Ebro...
(Royal Monastery of Our Lady of the Wheel), is located on the banks of the Ebro in Aragon
Aragon
Aragon is a modern autonomous community in Spain, coextensive with the medieval Kingdom of Aragon. Located in northeastern Spain, the Aragonese autonomous community comprises three provinces : Huesca, Zaragoza, and Teruel. Its capital is Zaragoza...
. Established in AD 1202, the edifice survives intact. The monastery is strongly connected to the Ebro, since it used one of the first large waterwheels built for the production of power in Spain. The monastery also diverted flow from the Ebro to create a circulating, hydrological central heating system for its buildings.
The river Ebro in 1938 was the starting ground of one of the most famous Republican
Second Spanish Republic
The Second Spanish Republic was the government of Spain between April 14 1931, and its destruction by a military rebellion, led by General Francisco Franco....
offensives of the Spanish Civil War
Spanish Civil War
The Spanish Civil WarAlso known as The Crusade among Nationalists, the Fourth Carlist War among Carlists, and The Rebellion or Uprising among Republicans. was a major conflict fought in Spain from 17 July 1936 to 1 April 1939...
. Known as the Battle of the Ebro
Battle of the Ebro
The Battle of the Ebro was the longest and bloodiest battle of the Spanish Civil War...
, the offensive ended in defeat for the Republican forces, although they enjoyed success in its first stages. They were not able to reach their objective of Gandesa
Gandesa
Gandesa is the capital of the comarca of Terra Alta, in the province of Tarragona, Catalonia, Spain.-History:In the place known as Coll del Moro there is an ancient Iberian archaeological site belonging to the Ilercavones tribe that lived in this area before Roman times.Gandesa has a church with...
.
Flow and floods
The Ebro 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 irrigationIrrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
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.
The decrease in river discharge has meant introduction of the salt wedge further into the river. 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
Sediment transport
Sediment transport is the movement of solid particles , typically due to a combination of the force of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained...
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 which are retained behind the dams.
River flow in Zaragoza
Zaragoza
Zaragoza , also called Saragossa in English, is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain...
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
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
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. It has some 95 breeding species of birds, is also very important for a wide range of overwintering species, and serves as an essential stopover point for large numbers of migratoryBird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
birds. The Ebro delta has the world's largest colony of Audouin's Gull
Audouin's Gull
The Audouin's Gull is a large gull restricted to the Mediterranean and the western coast of Saharan Africa. It breeds on small islands colonially or alone, laying 2-3 eggs on a ground nest...
s. In 2006 it held a record number of more than 15,000 pairs.
There are concerns about the ecological impact of introduction of foreign species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
that is almost always a burden, affecting much of the original ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
introduced species rapidly caused the extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
of numerous indigenous species. The introduction of American crayfish Procambarus clarkii
Procambarus clarkii
Procambarus clarkii is a freshwater crayfish species, native to the Southeastern United States, but found also on other continents, where it is often an invasive pest. It is known variously as the red swamp crawfish, red swamp crayfish, Louisiana crawfish, Louisiana crayfish or mudbug.-Range and...
has resulted in economic losses, introduced elsewhere for cultivation, its success is attributable to its ability to colonise disturbed habitats that would be unsuitable for the edible iberian crayfish
Astacus astacus
Astacus astacus, the European crayfish, noble crayfish or broad-fingered crayfish, is the most common species of crayfish in Europe, and a traditional foodstuff. Like other crayfish, Astacus astacus is restricted to fresh water, living only in unpolluted streams, rivers and lakes...
. The semiacuatic rodent Myocastor coypus or nutria is presuming to expand in some northwest tributaries of the head damaging crops and protected national parks in Basque Country
Basque Country (autonomous community)
The Basque Country is an autonomous community of northern Spain. It includes the Basque provinces of Álava, Biscay and Gipuzkoa, also called Historical Territories....
.
The zebra mussel
Zebra mussel
The zebra mussel, Dreissena polymorpha, is a small freshwater mussel. This species was originally native to the lakes of southeast Russia being first described in 1769 by a German zoologist Peter Simon Pallas in the Ural, Volga and Dnieper rivers. They are still found nearby, as Pontic and Caspian...
, an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
, is expanding upstream in Ebro waters. Due to its rapid rate of reproduction, the species adversely affects the port underwater machinery as well as that of dams and hydroelectric plants, in addition to competing with native species. Following the introduction of Wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...
are fishes whose number is in clear and rapid decline. Since its introduction in the reservoir Mequinenza in 1974 - has spread to other parts of the Ebro basin over Ebro and its tributaries, especially river Segre. Some endemics species of iberian barbels, genus Barbus
Barbus
Barbus is a ray-finned fish genus in the family Cyprinidae. The type species of Barbus is the Common Barbel, first described as Cyprinus barbus and now named Barbus barbus...
in the Cyprinidae, having once been abundant especially in the Ebro river. Competition and predation by Wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...
has caused its complete disappearance in the middle channel Ebro around 1990. The ecology of the river also, has now a major development in the amount of aquatic vegetation, seaweed and algae. Barbel species from mountain stream tributary of the Ebro that Wels catfish
Wels catfish
The wels catfish , also called sheatfish, is a large catfish found in wide areas of central, southern, and eastern Europe, and near the Baltic and Caspian Seas. It is a scaleless fresh and brackish water fish recognizable by its broad, flat head and wide mouth...
has not colonized, were not affected.
See also
- Imperial Channel of Aragon (Canal Imperial de Aragón)
- List of rivers of Spain
- Hydrological transport modelHydrological transport modelAn hydrological transport model is a mathematical model used to simulate river or stream flow and calculate water quality parameters. These models generally came into use in the 1960s and 1970s when demand for numerical forecasting of water quality was driven by environmental legislation, and at...
External links
- The River Ebro and Delta
- The Ebro Delta from Space
- The Ebro Delta at Google Maps
- Photo gallery of the Ebro Delta and surrounding area: birds, landscapes and people
- The Trinidad Salt Pans within the Ebro River Delta Nature Reserve
- Awarded "EDEN - European Destinations of Excellence" non traditional tourist destination 2009