The Agencia Vasca del Agua (URA) put out to tender the works to restore the Armaola fish pass on the river Oria at Segura (Gipuzkoa) on 2 October 2026. The reason is the partial failure of the pass, built in 2011, which was originally around 70 metres long and overcame a drop of 4.15 metres. Parts of the structure were damaged by flood forces. The estimated construction budget is €78,566 excluding VAT, with a planned construction period of five weeks.
The core of the project is to rebuild the lower section over 23 metres, which is intended to connect the surviving upper sections with the current riverbed. The design provides for a maximum gradient of 6% to allow different fish species to migrate. The technical plan is to install loose-laid stones with open joints: gaps between the blocks will provide habitat for flora and fauna and promote more natural water flow. The fish pass is about 1.4 kilometres south of the centre of Segura, on the upper Oria.
According to the authorities, in the years after it opened the structure proved effective in enabling trout populations found in this stretch to move upstream. The planned repairs are intended to restore full functionality. URA stresses that improved longitudinal connectivity should make it easier for migratory species to move between areas and thereby contribute to the river’s ecological status.
The construction site lies within the Special Area of Conservation ZEC ES2120005 Oria Garaia/Alto Oria, part of the European Natura 2000 network. Project documents list species found in this stretch, including the Piscardo (Phoxinus bigerri), the Locha (Barbatula barbatula), the brown trout (Salmo trutta fario) and the European eel (Anguilla anguilla). Measures to prevent adverse impacts include carrying out work outside particularly sensitive breeding and migration periods, creating dry work areas with dams, and using sediment barriers to prevent material entering downstream stretches of the river. Access will use existing construction tracks to protect riverside trees and valuable habitats.
The tender is part of wider restoration efforts under the European project LIFE KANTAURIBAI, in which URA is a partner. The aim is to improve the conservation status of river habitats in several Natura 2000 sites in the catchment area on the Bay of Biscay coast. Structures across rivers, such as weirs and sills, are considered major barriers to fish passage; removing them or making them passable is a key focus of river restoration in the upper Oria.
Editor: Mira Cadena (Article created with AI assistance).