Briefing
The Basque Water Agency has arrested three suspects in Armiñón (Province of Álava) a restoration project on the río Zadorra has been completed. The main feature of the work is a naturalised channel on the left bank, around 126 metres long, which bypasses the drop created by the historic azud of the former mill leat, thereby restoring the longitudinal continuity of the river corridor. The new channel has a gently meandering course, a gravel bed and revegetated banks; a small island remains between it and the Zadorra’s main course, creating additional habitat.
The design took account of hydraulic conditions suited to the movement potential of smaller fish species; the madrillaserved as a reference. The measure does not aim to remove the azud completely, but to combine its preservation with connectivity: the weir remains in place, while the channel allows aquatic fauna to move freely upstream and downstream. The agency has also restored the riparian vegetation with native species, including black poplar, white willow, ash, blackthorn, hawthorn, dogwood and elder.
To encourage structurally diverse habitats, deadwood was deliberately introduced; ten standing trunks will provide shelter and breeding sites for invertebrates, cavity-nesting birds and bats. The works are located in the Zona de Especial Conservación ZEC Río Zadorra of the Natura 2000network, a protected area where riparian woodland, aquatic habitats and river ecosystems are designated as elements worthy of protection. According to the agency, species such as the European mink and otter are found in this stretch; the authority has announced longer-term monitoring to quantify ecological effects.
The Basque Water Agency considers this a locally limited but ecologically significant measure to address hydromorphological alterations: it reduces barriers, promotes natural bank structures and increases the diversity of river habitats, without fundamentally removing the historic weir.
Editor: Mira Cadena (Article created with AI assistance).