Oria River
Encyclopedia
The Oria ˈoɾja is a river in the Basque Country
Basque Country (historical territory)
The Basque Country is the name given to the home of the Basque people in the western Pyrenees that spans the border between France and Spain on the Atlantic coast....

 at the north of the Iberian Peninsula
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...

. It's one of a series of Basque rivers flowing into the Bay of Biscay
Bay of Biscay
The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

 (Atlantic basin) and the main river of the province Gipuzkoa in volume (25.6 m3/s), length (75 km) and basin (882.5 km2), the main feature of these rivers aligned south to north being their shortness. The maximum elevation at the source is 1,260 m, while at its lowest height the tidal influence extends inland up to Usurbil
Usurbil
Usurbil is a town and region located in the province of Gipuzkoa in the Autonomous Community of the Basque Country, in the North of Spain.It lies in an area well known for its sagardotegiak and the area adjacent to the river for its eels....

 (estuary). On this final stretch, many marsh and wetland strips have dotted the banks of the Oria, although some of them have been drained for agricultural and building purposes.

It rises at the south of the municipality of Zegama
Zegama
Zegama is a town and municipality in the Goierri region of the province of Gipuzkoa, in the autonomous community of the Basque Country, northern Spain...

 near the hamlet of Otzaurte and the San Adrian tunnel
San Adrian (tunnel)
The San Adrian tunnel or Lizarrate represents the most outstanding milestone in the historic inland Basque route of the Way of St. James. It consists of a natural cave carved by water erosion in the rock with an opening on either side north and south; it also holds an hermitage inside...

, harvesting the waters of the north-eastern side of the mountain range Aizkorri, so the river results from the merging of several streams. The first town it crosses is the very nucleus of Zegama
Zegama
Zegama is a town and municipality in the Goierri region of the province of Gipuzkoa, in the autonomous community of the Basque Country, northern Spain...

, with other major towns of Gipuzkoa being located on the river, e.g. Beasain
Beasáin
Beasain is a town and municipality located in the Goierri region of the province of Gipuzkoa, in the Autonomous Community of the Basque Country, northern Spain. It has an important industry of railroad vehicles and related equipment that exports its production to all the world.-External links:* *...

, Ordizia
Ordizia
Ordizia is a town and municipality located in the Goierri region of the province of Gipuzkoa, in the autonomous community of the Basque Country, northern Spain.The professional cycle road race Prueba Villafranca de Ordizia is held yearly in Ordizia....

, Tolosa
Tolosa, Spain
Tolosa is a town and municipality to the south of Donostia-San Sebastián in the Basque province of Gipuzkoa, Spain. It is located in a valley of the river Oria and overlooked by Uzturre, a white cross-topped mountain.-Famous people from Tolosa:...

, Andoain
Andoain
Andoain is a town located in the province of Gipuzkoa, in the autonomous community of Basque Country, in the north of Spain. Nowadays it has a population above 13,000 inhabitants, which has been decreasing since 1981....

, Lasarte-Oria
Lasarte-Oria
Lasarte-Oria is a town located in the province of Gipuzkoa, in the Autonomous Community of Basque Country, northern Spain.-External links:* Information available in Spanish and Basque.* Information available in Spanish...

, Usurbil
Usurbil
Usurbil is a town and region located in the province of Gipuzkoa in the Autonomous Community of the Basque Country, in the North of Spain.It lies in an area well known for its sagardotegiak and the area adjacent to the river for its eels....

 and finally Orio
Orio
Orio is a fishing town located in the province of Gipuzkoa in the Basque Autonomous Community, northern Spain, with the town nucleus lying on the river Oria, roughly one mile away from its mouth by the Bay of Biscay....

 at the mouth. From Lasarte-Oria
Lasarte-Oria
Lasarte-Oria is a town located in the province of Gipuzkoa, in the Autonomous Community of Basque Country, northern Spain.-External links:* Information available in Spanish and Basque.* Information available in Spanish...

 to Orio
Orio
Orio is a fishing town located in the province of Gipuzkoa in the Basque Autonomous Community, northern Spain, with the town nucleus lying on the river Oria, roughly one mile away from its mouth by the Bay of Biscay....

 the sinuous and traffic laden coastal road N-634 twists along.

The Oria is a central river and an important axis for the province Gipuzkoa. The major road A-1 (European route E-5 E-80) runs along the Oria most of the time, as well as the Spanish Northern Railway, right from its rise on the slopes of Aizkorri. Its watershed holds a population of 128,000 inhabitants, most of the lowland being heavily inhabited, while the area of its southernmost stretch is sparsely populated.

Environmental condition and fauna

The banks of the river were intensely industrialized starting in the middle of the 19th century and later, so the river grew conspicuously polluted up to the 1980s, with almost all its river fauna becoming extinct. At that point, its environmental situation began to revert, the river showing currently a healthy condition. There exists an instable trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

 population downstream of Andoain, while other fish prevail and remain steady, i.e. Cyprinidae such as barbel
Barbel (fish species)
Barbels are group of small carp-like freshwater fish, almost all of the genus Barbus. They are usually found in gravel and rocky-bottomed slow-flowing waters with high dissolved oxygen content. A typical adult barbel will range from 25 to 100 cm in length and weigh anywhere between 200 g...

 (Barbus graellsi), ezkailu (Phoxinus
Phoxinus
Phoxinus is a genus of freshwater fish in the carp family of order Cypriniformes. The type species is Phoxinus phoxinus, the Common Minnow. The North American members of this genus are known as daces, and the Old World ones as Eurasian minnows. The latter term is also used specifically for P...

 phoxinus
) and ray-finned fish (Chondrostoma toxostoma arrigonis
Chondrostoma arrigonis
Parachondrostoma arrigonis is a species of cyprinid fish endemic to Spain only found in the Júcar River basin. Its natural habitat is rivers.It is threatened by habitat loss.-References:* Crivelli, A.J. 2005. . Downloaded on 19 July 2007....

). A stretch of the estuary by the village Aginaga is known for its baby eels, bred and harvested for human consumption before they grow up, providing for a much appreciated and dearly paid for culinary dish, while they were totally neglected just some decades ago.

Main tributaries

There are several streams and small rivers flowing into the Oria. The main tributaries are Leitzaran
Leitzaran
The Leitzaran is a river and a valley in the Navarre and the Basque Country . It flows into the river Oria from its right.Its source is in the Leitza municipality in Navarre, and it is 42 km long. It enters into Gipuzkoa in a place called Urto...

 in Andoain
Andoain
Andoain is a town located in the province of Gipuzkoa, in the autonomous community of Basque Country, in the north of Spain. Nowadays it has a population above 13,000 inhabitants, which has been decreasing since 1981....

 and Araxes in Tolosa
Tolosa, Spain
Tolosa is a town and municipality to the south of Donostia-San Sebastián in the Basque province of Gipuzkoa, Spain. It is located in a valley of the river Oria and overlooked by Uzturre, a white cross-topped mountain.-Famous people from Tolosa:...

.

See also

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