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| Oria | |
|---|---|
 The Oria river on its way throughLasarte-Oria with mountBuruntza in the background | |
.png) | |
| Location | |
| Country | Spain |
| Physical characteristics | |
| Source | |
| • location | Basque Mountains |
| Mouth | |
• location | Cantabrian Sea (Bay of Biscay) |
| Length | 75 km (47 mi) |
| Basin size | 882.5 km2 (340.7 sq mi) |
| Discharge | |
| • average | 25.6 m3/s (900 cu ft/s) |
TheOria[ˈoɾja] is a river in theBasque Country at the north of theIberian Peninsula. It's one of a series of Basque rivers flowing into theBay of Biscay (Atlantic basin) and the main river of the provinceGipuzkoa 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 toUsurbil (estuary). On this final stretch, many marsh and wetland strips dotted the banks of the Oria, although some of them have been drained for agricultural and building purposes.[1]
The river rises at the south of the municipality ofZegama near the hamlet ofOtzaurte and theSan Adrian tunnel, harvesting the waters of the north-eastern side of the mountain rangeAizkorri, so the river results from the merging of several streams. The first town it crosses is the very nucleus ofZegama, with other major towns ofGipuzkoa being located on the river, e.g.Beasain,Ordizia,Tolosa,Andoain,Lasarte-Oria,Usurbil and finallyOrio at the mouth. FromLasarte-Oria toOrio, the sinuous and traffic laden coastal road N-634 winds along.
The Oria is a central river and an important axis for the province ofGipuzkoa. 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 ofAizkorri. 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.
The banks of the river were intensely industrialized starting in the middle of the 19th century and later; 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 unstabletrout population downstream of Andoain, while other fish prevail and remain steady, i.e.Cyprinidae such asbarbel (Barbus graellsi),ezkailu (Phoxinus phoxinus) and ray-finned fish (Chondrostoma toxostoma arrigonis). A stretch of the estuary by the villageAginaga is known for its baby eels, bred and harvested for human consumption before they grow up, providing for a much appreciated and dearly paid delicacy, while they were totally neglected just some decades ago.
There are several streams and small rivers flowing into the Oria. The main tributaries areLeitzaran inAndoain andAraxes inTolosa.
43°17′25″N2°07′55″W / 43.29028°N 2.13194°W /43.29028; -2.13194