, 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 , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

, subdivision_type2 = Region , subdivision_name2 =

Cantabria Cantabria (, also , , Cantabrian: ) is an autonomous community in northern Spain with Santander as its capital city. It is called a ''comunidad histórica'', a historic community, in its current Statute of Autonomy. It is bordered on the east ...

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) The Basque Country (; eu, Euskadi ; es, País Vasco ), also called Basque Autonomous Community ( eu, Euskal Autonomia Erkidegoa, links=no, EAE; es, Comunidad Autónoma del País Vasco, links=no, CAPV), is an Autonomous communities of Spain, a ...

La Rioja La Rioja () is an autonomous community and province in Spain, in the north of the Iberian Peninsula. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, and N� ...

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 Catalonia (; ca, Catalunya ; Aranese Occitan: ''Catalonha'' ; es, Cataluña ) is an autonomous community of Spain, designated as a ''nationality'' by its Statute of Autonomy. Most of the territory (except the Val d'Aran) lies on the north ...

Valencian Community The Valencian Community ( ca-valencia, Comunitat Valenciana, es, Comunidad Valenciana) is an autonomous community of Spain. It is the fourth most populous Spanish autonomous community after Andalusia, Catalonia and the Community of Madrid with ...

, 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 ...

, 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 ...

, 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 The Zadorra is a river tributary of the Ebro in the Basque Country at the north of the Iberian Peninsula. The river flows across province Álava all along (with the exception of Burgos' exclave La Puebla de Arganzon) till it pours into the Ebro n ...

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 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 sout ...

, 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 The Cidacos River is a tributary of the Ebro. Its source is Los Campos, in Soria, and it flows for 77 km (48 mi) until its reaches the Ebro at Calahorra (La Rioja). It flows through or past various towns like Villar del Río, Yangua ...

, 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 The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

, in

. It rises in

and flows , almost entirely in an

east-southeast The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each sep ...

direction. It flows into the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

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

. In the Iberian peninsula, it ranks second in length after the

Tagus The Tagus ( ; es, Tajo ; pt, Tejo ; see #Name, below) is the longest river in the Iberian Peninsula. The river rises in the Montes Universales near Teruel, in mid-eastern Spain, flows , generally west with two main south-westward sections ...

and second in discharge volume, and drainage basin, after the

Douro The Douro (, , ; es, Duero ; la, Durius) is the highest-flow river of the Iberian Peninsula. It rises near Duruelo de la Sierra in Soria Province, central Spain, meanders south briefly then flows generally west through the north-west part of ...

. It is the longest river entirely within Spain; the other two mentioned flow into

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

. It is also the second-longest river in the Mediterranean basin, after the

Nile The Nile, , Bohairic , lg, Kiira , Nobiin language, Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered ...

. 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 ...

; Frías and

Miranda de Ebro Miranda de Ebro (Spanish: iˈɾan̪da ðe ˈeβɾo is a city on the Ebro river in the Burgos (province), province of Burgos in the autonomous community of Castile and León, Spain. It is located in the north-eastern part of the province, on th ...

; Haro,

Logroño Logroño () is the capital of the province of La Rioja, situated in northern Spain. Traversed in its northern part by the Ebro River, Logroño has historically been a place of passage, such as the Camino de Santiago. Its borders were disputed b ...

Calahorra Calahorra [] ( an, Calagorra, la, Calagurris) is a municipality in the comarca of Rioja Baja, near the border with Navarre on the right bank of the Ebro. During Ancient Rome, Ancient Roman times, Calahorra was a municipium known as ''Calagurris ...

, and Alfaro in

; Tudela in

; 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 Zaragoza, also known in English as Saragossa,''Encyclopædia Britannica'"Zaragoza (conventional Saragossa)" is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain. It lies by the Ebro river and its tributari ...

; and

Flix Flix () is a town in the ''Comarques of Catalonia, comarca'' of Ribera d'Ebre, Catalonia, Spain. Situated on a promontory by the Ebro river, the town occupied an important strategic position. Situated on the Madrid–Barcelona railway line, ...

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 Xerta is a town and municipality of the ''comarca'' of Baix Ebre. It is established in a sharp bend to the right of the river Ebre, about 12 km upstream from the city of Tortosa in the province of Tarragona, Catalonia, Spain. Geographical c ...

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 Tortosa (; ) is the capital of the ''Catalonia/Comarques, comarca'' of Baix Ebre, in Catalonia, Spain. Tortosa is located at above sea level, by the Ebro river, protected on its northern side by the mountains of the Cardó Massif, of which Buin ...

, and

Amposta Amposta () is the capital of the ''comarca'' of Montsià, in the province of Tarragona, Catalonia, Spain, 190 km south of Barcelona on the Mediterranean Coast. It is located at 8 metres above sea level, on the Ebre river, not far from its mo ...

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 ...

(

Geography

Upper part and tributaries

The source of the river Ebro is in the

Cantabrian Mountains , etymology=Named after the Cantabri , photo=Cordillera Cantábrica vista desde el Castro Valnera.jpg , photo_caption=Cantabrian Mountains parallel to the Cantabrian Sea seen from Castro Valnera in an east-west direction. In the background, th ...

, in

, from the Latin ''Fontes Iberis'', fount/source of the Ebro. Close by is a large

artificial lake A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

, ''Embalse del Ebro'', created by its damming. The upper Ebro rushes through rocky gorges in

Burgos Province The Province of Burgos is a province of northern Spain, in the northeastern part of the autonomous community of Castile and León. It is bordered by the provinces of Palencia, Cantabria, Vizcaya, Álava, La Rioja, Soria, Segovia, and Valladolid. ...

. Flowing roughly eastwards it passes ''las conchas de Haro'' and begins forming a wider river valley among

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

rocks when it reaches

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 The Iberian System ( es, Sistema Ibérico, ) is one of the major systems of mountain ranges in Spain. It consists of a vast and complex area of mostly relatively high and rugged mountain chains and massifs located in the central region of th ...

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

Bilbao ) , motto = , image_map = , mapsize = 275 px , map_caption = Interactive map outlining Bilbao , pushpin_map = Spain Basque Country#Spain#Europe , pushpin_map_caption ...

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 The Pyrenees (; es, Pirineos ; french: Pyrénées ; ca, Pirineu ; eu, Pirinioak ; oc, Pirenèus ; an, Pirineus) is a mountain range straddling the border of France and Spain. It extends nearly from its union with the Cantabrian Mountains to C ...

mountains, which run along the border with

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. 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 Continental may refer to: Places * Continent, the major landmasses of Earth * Continental, Arizona, a small community in Pima County, Arizona, US * Continental, Ohio, a small town in Putnam County, US Arts and entertainment * ''Continental'' (al ...

. This implies summer/winter seasonal contrast and a rather dry climate. Summers of the Ebro Valley most often mirror those of a

semiarid climate A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...

; some of them see more breaks of storms or showers, yet others are more

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ar ...

bringing

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

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 Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

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 A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers and freezing ...

with extreme temperatures. There are many

ground frost Ground frost refers to the various coverings of ice produced by the direct deposition of water vapor on objects and trees, whose surfaces have a temperature below the freezing point of water (0 °C, 32 °F). Types The three main typ ...

s on clear nights, and sporadic

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

falls.

Soil and geology

The natural

topsoil Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Description Topsoil is composed of mineral particles and organic matt ...

s 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 An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...

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 Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolosto ...

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

biome A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...

s 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 Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaf, leaves, short Internode (botany), internodes (the distance between leaves along the stem) and leaf orientation which is paral ...

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 A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

'', 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 ''Pistacia'' is a genus of flowering plants in the cashew family, Anacardiaceae. It contains 10 to 20 species that are native to Africa and Eurasia from the Canary Islands, all of Africa, and southern Europe, warm and semidesert areas across Asi ...

'', ''

Rosmarinus Rosmarinus ( ) is a small taxonomic clade of woody, perennial herbs with fragrant evergreen needle-like leaves in the family Lamiaceae, native to the Mediterranean Basin. In 2017 the species in the genus ''Rosmarinus'' were moved into the large ...

'', ''

Thymus The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...

'', 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 An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...

''), 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 (

extremophile An extremophile (from Latin ' meaning "extreme" and Greek ' () meaning "love") is an organism that is able to live (or in some cases thrive) in extreme environments, i.e. environments that make survival challenging such as due to extreme temper ...

s as to salt) abound in zones of endorheic lagoons and their feeder creeks.

Tamarix The genus ''Tamarix'' (tamarisk, salt cedar, taray) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may refer to the Tam ...

-covered, these include endemic species of

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited in ...

s, chenopodiaceas,

plumbaginaceae Plumbaginaceae is a family of flowering plants, with a cosmopolitan distribution. The family is sometimes referred to as the leadwort family or the plumbago family. Most species in this family are perennial herbaceous plants, but a few grow as ...

, ruppiaceaes, ''

Carex ''Carex'' is a vast genus of more than 2,000 species of grass-like plants in the family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of genus ''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 dam (1955), and

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

before discharging in a

on the Mediterranean Sea close to

in the province of

Tarragona Tarragona (, ; Phoenician: ''Tarqon''; la, Tarraco) is a port city located in northeast Spain on the Costa Daurada by the Mediterranean Sea. Founded before the fifth century BC, it is the capital of the Province of Tarragona, and part of Tar ...

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

, is at , or 20km² less, one of the largest

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

s 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) **

. Recorded and thus confirmed as a

seaport A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

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 Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

deposition by the Ebro and removal of this material by wave

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

. 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 , name_etymology = , image = Zaragoza shel.JPG , image_size = , image_caption = The Ebro River in Zaragoza , map = SpainEbroBasin.png , map_size = , map_caption = The Ebro ...

( 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 Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a letter ...

called it the ''Hibēr'', ''Ibēr'', or ''Ibērus flūmen'', leading to its current name. The

Iberian peninsula The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

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 Basque may refer to: * Basques, an ethnic group of Spain and France * Basque language, their language Places * Basque Country (greater region), the homeland of the Basque people with parts in both Spain and France * Basque Country (autonomous co ...

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 Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a letter ...

(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 The Roman Republic ( la, Res publica Romana ) was a form of government of Rome and the era of the classical Roman civilization when it was run through public representation of the Roman people. Beginning with the overthrow of the Roman Kin ...

, 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 Sagunto ( ca-valencia, Sagunt) is a municipality of Spain, located in the province of Valencia, Valencian Community. It belongs to the modern fertile ''comarca'' of Camp de Morvedre. It is located c. 30 km north of the city of Valencia, cl ...

(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 A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of monastics, monks or nuns, whether living in communities or alone (hermits). A monastery generally includes a place reserved for prayer which ...

in Spain, Real Monasterio de Nuestra Señora de Rueda ( 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 Republican can refer to: Political ideology * An advocate of a republic, a type of government that is not a monarchy or dictatorship, and is usually associated with the rule of law. ** Republicanism, the ideology in support of republics or agains ...

offensives of the

Spanish Civil War The Spanish Civil War ( es, Guerra Civil Española)) or The Revolution ( es, La Revolución, link=no) among Nationalists, the Fourth Carlist War ( es, Cuarta Guerra Carlista, link=no) among Carlists, and The Rebellion ( es, La Rebelión, lin ...

. Known as the

Battle of the Ebro The Battle of the Ebro ( es, Batalla del Ebro, ca, Batalla de l'Ebre) was the longest and largest battle of the Spanish Civil War and the greatest, in terms of manpower, logistics and material ever fought on Spanish soil. It took place between Ju ...

, 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 Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

and the evaporation (higher than the rainfall, due to low rainfall, high sunshine and strong and dry winds) from

reservoirs A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...

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

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 An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

; the introduced species have rapidly caused the

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually 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 ...

of numerous indigenous species. In past times numerous

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...

s, endorheic

saltwater Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, ...

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...

s, 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

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es were drained, dried or filled. Almost entire

riparian forest A riparian forest or riparian woodland is a forested or wooded area of land adjacent to a body of water such as a river, stream, pond, lake, marshland, estuary, canal, sink or reservoir. Etymology The term riparian comes from the Latin word '' ...

s 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

meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank ...

s 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

s 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 gull Audouin's gull (''Ichthyaetus audouinii'') is a large gull restricted to the Mediterranean and the western coast of Saharan Africa and the Iberian Peninsula. The genus name is from Ancient Greek ''ikhthus'', "fish", and ''aetos'', "eagle", and t ...

s. In 2006 it held a record number of more than 15,000 pairs, its highest to date. The introduction of American crayfish ''

Procambarus clarkii ''Procambarus clarkii'', known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduc ...

'' 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 The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

prohibits their sale, notably the huge

Wels catfish The wels catfish ( or ; ''Silurus glanis''), also called sheatfish or just wels, is a large species of catfish native to wide areas of central, southern, and eastern Europe, in the basins of the Baltic, Black and Caspian Seas. It has been introd ...

. The

zebra mussel The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in ma ...

, 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 In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some ...

, genus ''

Barbus ''Barbus'' is a genus of ray-finned fish in the family Cyprinidae. The type species of ''Barbus'' is the common barbel, first described as ''Cyprinus barbus'' and now named ''Barbus barbus''. ''Barbus'' is the namesake genus of the subfamily B ...

'' 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
Awarded "EDEN - European Destinations of Excellence" non traditional tourist destination 2009
in the ''

Columbia Encyclopedia The ''Columbia Encyclopedia'' is a one-volume encyclopedia produced by Columbia University Press and, in the last edition, sold by the Gale Group. First published in 1935, and continuing its relationship with Columbia University, the encyclopedi ...

'' {{Authority control Rivers of Spain Rivers of Cantabria Rivers of Castile and León Rivers of La Rioja (Spain) Rivers of Navarre Rivers of Aragon Rivers of Catalonia * Rivers of Burgos European drainage basins of the Mediterranean Sea