, name_etymology = , image = Zaragoza shel.JPG , image_size = , image_caption = The Ebro River in Zaragoza , map = SpainEbroBasin.png , map_size = , map_caption = The Ebro river basin , pushpin_map = , pushpin_map_size = , pushpin_map_caption= , subdivision_type1 = Country , subdivision_name1 = Spain , subdivision_type2 = Region , subdivision_name2 = Cantabria,

Castile and León Castile and León ( es, Castilla y León ; ast-leo, Castiella y Llión ; gl, Castela e León ) is an autonomous community in northwestern Spain. It was created in 1983, eight years after the end of the Francoist regime, by the merging of the ...

, Basque Country (autonomous community), La Rioja,

Navarre Navarre (; es, Navarra ; eu, Nafarroa ), officially the Chartered Community of Navarre ( es, Comunidad Foral de Navarra, links=no ; eu, Nafarroako Foru Komunitatea, links=no ), is a foral autonomous community and province in northern Spain, ...

Aragon Aragon ( , ; Spanish and an, Aragón ; ca, Aragó ) is an autonomous community in Spain, coextensive with the medieval Kingdom of Aragon. In northeastern Spain, the Aragonese autonomous community comprises three provinces (from north to sou ...

, Catalonia, Valencian Community , subdivision_type3 = , subdivision_name3 = , length = , width_min = , width_avg = , width_max = , depth_min = , depth_avg = , depth_max = , discharge1_location=

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

, discharge1_min = , discharge1_avg = , discharge1_max = , source1 = , source1_location =

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 Latin (, or , ) is a ...

, Cantabria, Spain , source1_coordinates= , source1_elevation = , mouth = , mouth_location = Mediterranean Sea,

Province of Tarragona 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, Lérida and Barcelona and by the Mediterranean Sea. The province's p ...

, Catalonia, Spain , mouth_coordinates = , mouth_elevation = , progression = , river_system = Ebro basin , basin_size = , tributaries_left = Nela, Jerea,

Bayas Bayas () is a commune in the Gironde department in southwestern France. Population See also *Communes of the Gironde department The following is a list of the 535 Communes of France, communes of the Gironde Departments of France, department ...

, Zadorra,

Ega Ega or EGA may refer to: Military * East German Army, the common western name for the National People's Army * Eagle, Globe, and Anchor, the emblem of the United States Marine Corps People * Aega (mayor of the palace), 7th-century noble of Neus ...

, Arga, Aragón, Gállego,

Cinca Neonatal-onset multisystem inflammatory disease is a rare genetic periodic fever syndrome which causes uncontrolled inflammation in multiple parts of the body starting in the newborn period. Symptoms include skin rashes, severe arthritis, and chr ...

Segre Segre may refer to: * Segre (surname) * Sègre (department), a former department of France * Segre River, a river in Catalonia * Segré, a commune in Maine-et-Loire, France * Segré, Burkina Faso * '' Diari Segre'' or ''Segre'', a Spanish- and Ca ...

, tributaries_right =

Oca OCA or Oca may refer to: Places and jurisdictions * The ancient town and bishopric Oca in Asia Minor (present Asia Turkey), now a Latin Catholic titular see * The former Spanish Oca, modern Villafranca Montes de Oca, also see of a medieval bis ...

, Oja, Tirón,

Najerilla The river Najerilla is a tributary of the river Ebro, Spain's most voluminous river. The Najerilla rises in the province of Burgos and then flows through La Rioja. Archaeology The valley has been inhabited since prehistoric times. Two Iron Age h ...

, Iregua, Cidacos, Alhama,

Jalón Xaló (; es, Jalón ), is a municipality in the ''comarca'' of Marina Alta in the Valencian Community, Spain. Geography The town of Jalón is located in the Jalón Valley. The Jalón or Gorgos river crosses the town, which has a length of . ...

Huerva The Huerva River is a river in Aragon, Spain. It is a tributary of the Ebro. Its mean annual discharge is only . Course This long river rises in the Sierra de Cucalón, near Fonfría in the Jiloca Comarca. Flowing northwestwards near Lagueruel ...

, Martín,

Guadalope The Guadalope (Guadalop in Catalan and Aragonese) is a river in Aragon, Spain. It is a tributary of the Ebro (Ebre in Catalan). Course This long river rises in the Sierra de Gúdar, near Villarroya de los Pinares and Miravete de la Sier ...

, Matarranya , custom_label = , custom_data = , extra = The Ebro (Spanish and ; ca, Ebre ) is a river of the north and northeast of the Iberian Peninsula, in Spain. It rises in Cantabria and flows , almost entirely in an east-southeast direction. It flows into the Mediterranean Sea forming a

delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also re ...

in the

, in southern Catalonia. In the Iberian peninsula, it ranks second in length after the Tagus and second in discharge volume, and drainage basin, after the Douro. It is the longest river entirely within Spain; the other two mentioned flow into Portugal. It is also the second-longest river in the Mediterranean basin, after the Nile. The Ebro flows through many cities ( es, ciudades):

Reinosa Reinosa is a municipality in Cantabria, Spain. , it has 10,307 inhabitants. The municipality, one of the smallest by land area in Cantabria, is notable for being one of the nearest towns to the headwaters of the Ebro River. It is surrounded by th ...

in Cantabria; Frías and Miranda de Ebro in

; Haro, Logroño, Calahorra, and Alfaro in La Rioja;

Tudela Tudela may refer to: *Tudela, Navarre, a town and municipality in northern Spain ** Benjamin of Tudela Medieval Jewish traveller ** William of Tudela, Medieval troubadour who wrote the first part of the ''Song of the Albigensian Crusade'' ** Battl ...

; Alagón,

Utebo Utebo ( an, Utevo) is a town located in the province of Zaragoza, Aragon, Spain. At the time of the 2011 census (INE), the municipality had a population of 18,602 inhabitants, being the third most populous town of the province, only surpassed by ...

, and Zaragoza in

; and Flix,

Móra d'Ebre Móra 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 road to Reus and Gandesa, the N-230 road to Lleida. The ...

Benifallet Benifallet 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 kayaker A kayak is a small, narrow watercraf ...

Tivenys Tivenys is a municipality in the ''comarca'' of the Baix Ebre in Tarragona province Catalonia, Spain. It is situated on the left bank of the Ebro river among the mountains of the Cardó-Boix Massif. Notable people * José Alcoverro José Alc ...

, Xerta,

Aldover Aldover 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. This line was dism ...

, Tortosa, and Amposta in the

province of Tarragona 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, Lérida and Barcelona and by the Mediterranean Sea. The province's p ...

( Catalonia).

Geography

Upper part and tributaries

The source of the river Ebro is in the Cantabrian Mountains, in

, Cantabria, from the Latin ''Fontes Iberis'', fount/source of the Ebro. Close by is a large artificial lake, ''Embalse del Ebro'', created by its damming. The upper Ebro rushes through rocky gorges in Burgos Province. Flowing roughly eastwards it passes ''las conchas de Haro'' and begins forming a wider river valley among limestone rocks when it reaches La Rioja and

. Southern tributaries rise on the nearby

watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...

, the Sistema Ibérico, a mountain range among those of Spain's centre. North of the headwaters is the Cantabrian mountain range (south of Bilbao and

Santander Santander may refer to: Places * Santander, Spain, a port city and capital of the autonomous community of Cantabria, Spain * Santander Department, a department of Colombia * Santander State, former state of Colombia * Santander de Quilichao, a m ...

). Much of the total water volume of the Ebro comes from its northern tributaries, which drain about of the southern slopes of the Pyrenees mountains, which run along the border with France. All of Andorra's drainage basin is in the Ebro, through the

Climate

Downstream from Cantabria the climate in the Ebro basin – the valley being isolated from sea air masses by surrounding mountains – becomes Mediterrean/Atlantic influenced and continental. This implies summer/winter seasonal contrast and a rather dry climate. Summers of the Ebro Valley most often mirror those of a semiarid climate; some of them see more breaks of storms or showers, yet others are more arid bringing drought save where advanced irrigation is used. The valley

flood plain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

s have rainfall between , with maxima in fall and spring. It is often covered with

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...

vegetation. Summers are hot and winters are cold. The dry summer season has temperatures of more than , occasionally reaching over . In winter, the temperatures often drop below . In some areas the vegetation depends heavily on moisture produced by condensation

fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influ ...

. It is a continental Mediterranean climate with extreme temperatures. There are many ground frosts on clear nights, and sporadic snowfalls.

Soil and geology

The natural topsoils across the plains are, outside of historically well-forested zones, thin. The subsoil being close to the surface is organically poor and quick-draining: calcareous, pebbly, stony layers. These are in places salt-rich, seeing some saltwater endorheic lagoons.

Karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

geological processes shaped the landscape of layers of soluble carbonate rock of extensive limestone

bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater ...

formed in an ancient seabed.

Flow volume

The valley expands and the Ebro's flow then becomes slower as its water volume increases, flowing across Aragon. There, larger 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.

Ecosystems

The biomes are diverse in these Mediterranean climate zones:

Mediterranean forests, woodlands, and scrub Mediterranean forests, woodlands, and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in ...

. Hinterlands are particularly distinctive on account of extensive sclerophyll shrublands known as

maquis Maquis may refer to: Resistance groups * Maquis (World War II), predominantly rural guerrilla bands of the French Resistance * Spanish Maquis, guerrillas who fought against Francoist Spain in the aftermath of the Spanish Civil War * The network ...

, or garrigues. The dominant species are ''

Quercus coccifera ''Quercus coccifera'', the kermes oak, is an oak bush in the ''Ilex'' section of the genus. It is native to the Mediterranean region and Northern African Maghreb, south to north from Morocco to France and west to east from Portugal to Cyprus an ...

'' (in drier areas) and ''

Quercus ilex ''Quercus ilex'', the evergreen oak, holly oak or holm oak is a large evergreen oak native to the Mediterranean region. It is a member of the ''Ilex'' section of the genus, with acorns that mature in a single summer. Description An evergreen tr ...

''. These trees form monospecific communities or communities integrated with '' Pinus'', Mediterranean

buckthorn ''Rhamnus'' is a genus of about 110 accepted species of shrubs or small trees, commonly known as buckthorns, in the family Rhamnaceae. Its species range from tall (rarely to ) and are native mainly in east Asia and North America, but found thr ...

s, ''

Myrtus ''Myrtus'' (commonly called myrtle) is a genus of flowering plants in the family Myrtaceae. It was first described by Swedish botanist Linnaeus in 1753. Over 600 names have been proposed in the genus, but nearly all have either been moved ...

'', ''

Chamaerops humilis ''Chamaerops'' is a genus of flowering plants in the family Arecaceae. The only currently fully accepted species is ''Chamaerops humilis'', variously called European fan palm or the Mediterranean dwarf palm. It is one of the most hardy palms, ...

'',

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' () of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arcti ...

s, '' Pistacia'', '' Rosmarinus'', '' Thymus'', and so on. The hinterland climate becomes progressively more continental and drier, and therefore there is an end from extreme temperatures accompanied by slow-growing dwarf juniper species to unvegetated desert steppes as in "llanos de Belchite" or "Calanda desert". The mountain vegetation is mostly coniferous forests that are drought-adapted, and hardier trees in the oak genus ('' Quercus''), typically less tolerant, in the wetter highlands.

Halophile The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ...

s ( extremophiles as to salt) abound in zones of endorheic lagoons and their feeder creeks. Tamarix-covered, these include endemic species of bryophytes, chenopodiaceas, plumbaginaceae, ruppiaceaes, '' Carex'', lythraceaes, asteraceaes, and others. Their presence is related to the marine origin of the valley and the extensive marine deposits. Just as it enters Catalonia, the valley narrows, and the river becomes constrained by mountain ranges, making wide bends. 3 massive dams have been built in this area:

Mequinenza dam Mequinenza Dam ( es, Presa de Mequinenza, links=no) is a concrete gravity dam in the province of Zaragoza, Spain. It impounds the Ebro creating a large reservoir, which is called ''Mar de Aragón''. About 35 km downstream of Mequinenza dam is ...

(

Province of Zaragoza Zaragoza (), also called Saragossa in English,''Encyclopædia Britannica''Zaragoza (conventional Saragossa)/ref> is a province of northern Spain, in the central part of the autonomous community of Aragon. Its capital is Zaragoza, which is also th ...

, 1955),

Riba-roja 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. The whole area is mountainous. See also *Puntal dels Escambrons ...

dam (1955), and Flix dam (1948), the latter two in the

. In the final section of its course the river bends southwards and flows through spectacular gorges. The calcareous cliffs and high, rocky hills of the

Serra de Cardó Serra (Latin for "saw") may refer to: People * Serra (footballer) (born 1961), Portuguese footballer * Serra (surname) * Serra (given name) Cities, towns, municipalities Brazil *Serra, Espírito Santo, a city in the Greater Vitória area *Ampar ...

almost abut the river separating the Mediterranean coastal strip. After passing the gorges, the Ebro bends again eastwards near Tortosa before discharging in a

on the Mediterranean Sea close to Amposta in the province of Tarragona.

The delta

The

Ebro Delta The Ebro Delta ( ca, Delta de l'Ebre, ; es, Delta del Ebro, ) is the delta region of the Ebro River ( ca, Ebre, links=no, es, Ebro, links=no) in the southwest of the Province of Tarragona in the region of Catalonia in Spain. It is located on ...

( ca, Delta de l'Ebre, links=no), in the

, Catalonia, is at , or 20km² less, one of the largest wetlands of the western Mediterranean. Designated a

Ramsar site A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention,8 ha (O) *** Permanent 8 ha (P) *** Seasonal Intermittent < 8 ha(Ts) **

Amposta. Recorded and thus confirmed as a seaport in the

Roman Warm Period The Roman Warm Period, or Roman Climatic Optimum, was a period of unusually-warm weather in Europe and the North Atlantic that ran from approximately 250 BC to AD 400. Theophrastus (371 – c. 287 BC) wrote that date trees could grow in Greece ...

in the 4th century, it is now well inland from the mouths. The rounded form of the delta attests to the subsequent balance between sediment deposition by the Ebro and removal of this material by wave erosion. The modern delta is in intensive

agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...

use for rice, fruit (in particular citrus), and vegetables. The Ebro delta also has numerous beaches, marshes, and salt pans that provide habitat for over 300 species of birds. The Ebro delta was classified as a wetland area of international interest by Spain's Bureau Mar in 1962. Since a phased-introduction law (1983 to 1986) Spain has designated as the Ebro Delta Natural Park ( ca, Parc Natural del Delta de l'Ebre, links=no) to protect its natural resources.Ebro Delta Natural Park
A network of canals and irrigation ditches dug by agricultural and conservation groups help to maintain the ecologic and economic resources of the delta.

Name

The Greeks called the river (''Ibēr''),(''abir''), ''ah'ir'' and the Romans called it the ''Hibēr'', ''Ibēr'', or ''Ibērus flūmen'', leading to its current name. The Iberian peninsula and the ''Hibērī'' or ''Ibērī'' (the people of the area) were named after the river.Westrem, Scott D. ''The Hereford Map: A Transcription and Translation of the Legends With Commentary'', page 328. Brepols, 2001. It is not known with any certainty whether the Greeks used a local native name for the river. Nor is it known what the word "''Ibēr''" or "''Hibēr''" might mean. In modern Basque the word ''ibar'' means 'valley' or 'watered meadow', while ''ibai'' means 'river', but there is no proof relating the etymology of the Ebro River with these Basque words. There are rivers in the Balkans called

Ibar Ibar may refer to: People * Ibar of Beggerin (died 500), Irish saint * Íbar of Killibar Beg, Irish saint * Hilmi Ibar (born 1947), Kosovar academic * José Ibar (born 1969), Cuban baseball player Places * Ibar District, a division of the Serbia ...

(Montenegro and Serbia) and Evros (Bulgaria and Greece).

History

antiquity Antiquity or Antiquities may refer to: Historical objects or periods Artifacts *Antiquities, objects or artifacts surviving from ancient cultures Eras Any period before the European Middle Ages (5th to 15th centuries) but still within the histo ...

, the Ebro was used as the dividing line between Roman (north) and

Carthaginian The term Carthaginian ( la, Carthaginiensis ) usually refers to a citizen of Ancient Carthage. It can also refer to: * Carthaginian (ship), a three-masted schooner built in 1921 * Insurgent privateers; nineteenth-century South American privateers, ...

(south) expansions after the

First Punic War The First Punic War (264–241 BC) was the first of three wars fought between Rome and Carthage, the two main powers of the western Mediterranean in the early 3rd century BC. For 23 years, in the longest continuous conflict and grea ...

(264–241 BC). When the Roman Republic, fearful of

Hannibal Hannibal (; xpu, 𐤇𐤍𐤁𐤏𐤋, ''Ḥannibaʿl''; 247 – between 183 and 181 BC) was a Carthaginian general and statesman who commanded the forces of Carthage in their battle against the Roman Republic during the Second Puni ...

'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 violation as an aggressive action by Rome and used the event as the catalyst to the

Second Punic War The Second Punic War (218 to 201 BC) was the second of three wars fought between Carthage and Rome, the two main powers of the western Mediterranean in the 3rd century BC. For 17 years the two states struggled for supremacy, primarily in Ital ...

. One of the earliest

Cistercian The Cistercians, () officially the Order of Cistercians ( la, (Sacer) Ordo Cisterciensis, abbreviated as OCist or SOCist), are a Catholic religious order of monks and nuns that branched off from the Benedictines and follow the Rule of Saint ...

monasteries in Spain,

Real Monasterio de Nuestra Señora de Rueda Rueda Abbey or Rueda de Ebro Abbey ( es, Real Monasterio de Nuestra Señora de Rueda, or the "Royal Monastery of Our Lady of the Wheel") is a former Cistercian monastery in Sástago in the Ribera Baja del Ebro comarca, province of Zaragoza, Aragon, ...

( Monastery of Our Lady of the Wheel), is located on the banks of the Ebro in

. Established in 1202, the edifice survives intact. The monastery is strongly connected to the Ebro, since it used one of the first large

waterwheel A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or metal), with a number of blades or buckets ...

s 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 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 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 l ...

Flow and floods

The Ebro is the most important river in Spain in terms of length, , and area of drainage basin, . However, the mean annual flow decreased by approximately 29 percent 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. The decrease in river discharge has meant introduction of the

salt wedge An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

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 , the salt wedge can occupy the last of the estuary, but when the discharge is between , the salt wedge can advance up to from the mouth. For less than , the salt wedge quickly advances to its maximum extent, reaching 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 percent during the last century. The drastic reduction in

sediment transport Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural system ...

implies a sediment deficit in the delta, which is causing the erosion of the coastline and lack of sediment replenishment. The unstable surface is due to weather changes and

tidal surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...

s. The river floods from time to time, although advance warning can now be given as a result of monitoring within the catchment area. The river flow in Zaragoza during floods, from the end of the 19th century is as follows: *March 1888: *January 1891: *February 1892: *January 1895: *March 1930: *December 1930: *October 1937: *January 1941: *February 1952: *January 1961: *November 1966: *January 1981: *February 2003: *March 2003: *April 2007: The Ebro poured into the delta from 27 March 2007 to 11 April 2007, with an average of per day.

Ecology

Academics and local government have criticised ecological impacts of: *dams *pollution from populations *factories *agricultural dumping. *

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

affecting the original ecosystem; the introduced species have rapidly caused the extinction of numerous indigenous species. In past times numerous lagoons, endorheic saltwater ponds, and freshwater

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s and marshes were drained, dried or filled. Almost entire riparian forests were cleared for crops or for

pulpwood Pulpwood is timber with the principal use of making wood pulp for paper production. Applications * Trees raised specifically for pulp production account for 15% of world pulp production, old growth forests 9% and second- and third- and more gener ...

forest plantations. Due to these changes numerous plant and animal species have disappeared. Due to dams and hydraulic canalization, the dynamics of the river have been altered and new scroll-bars, new

oxbow lake An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water. In South Texas, oxbows left by the Rio Grande are called '' resacas''. In Australia, oxbow lakes are call ...

s, and new abandoned meanders will not now be created. Over a period of time, many of these phenomena tend to dry out or fill in with sediments. Some small representatives of these river dynamics and wetlands are protected. The Ebro Delta Natural Park, covering , was finalised 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 migratory birds. The Ebro delta has the world's largest colony of Audouin's gulls. In 2006 it held a record number of more than 15,000 pairs, its highest to date. 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 deter the edible iberian crayfish. The semiaquatic rodent ''

Myocastor coypus The nutria (''Myocastor coypus''), also known as the coypu, is a large, herbivorous, semiaquatic rodent. Classified for a long time as the only member of the family Myocastoridae, ''Myocastor'' is now included within Echimyidae, the family of t ...

'' is beginning to expand in some northwest tributaries of the head damaging crops and protected national parks in the

Basque Country Basque Country may refer to: * Basque Country (autonomous community), as used in Spain ( es, País Vasco, link=no), also called , an Autonomous communities of Spain, autonomous community of Spain (shown in pink on the map) * French Basque Country o ...

. Fish caught in all lower reaches of the Ebro are high in

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

and the European Union prohibits their sale, notably the huge Wels catfish. The zebra mussel, an

, is expanding upstream in the Ebro's waters. Due to its rapid rate of reproduction, the species adversely affects the port's underwater machinery as well as that of dams and hydroelectric plants, in addition to competing with native species. Following the introduction of Wels catfish, many fish species' numbers are in clear and rapid decline. Since the Wels catfish's introduction in the

Mequinenza reservoir Mequinenza Dam ( es, Presa de Mequinenza, links=no) is a concrete gravity dam in the province of Zaragoza, Spain. It impounds the Ebro creating a large reservoir, which is called ''Mar de Aragón''. About 35 km downstream of Mequinenza dam is ...

in 1974, it has spread to other parts of the Ebro and its tributaries, especially the

. Some endemics species of iberian barbels, genus '' Barbus'' in the

Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest verte ...

, have declined drastically, having once been abundant, especially in the Ebro. Competition and predation by Wels catfish caused its complete disappearance in the middle channel Ebro around 1990. Barbel species from mountain stream tributaries of the Ebro that Wels catfish have not colonized were not affected. The ecology of the river also now has the problem of a major increase in aquatic vegetation, seaweed and algae.

Notes and citations

;Footnotes ;Citations

External links

*
The River Ebro and DeltaThe Ebro Delta at Google Maps
* ttp://www.flordeldelta.com/data_en/sal-gourmet.php The Trinidad Salt Pans within the Ebro River Delta Nature Reserve
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