Influence of the Construction of the Urdinbide Road Tunnel on the Autzagane Aquifer in Biscay (Spain)

The Urdinbide road tunnel goes through the Autzagane aquifer. This important aquifer is located within hydrogeological area of Urdaibai Biosphere Reserve, one most biosphere reserves in Iberian Peninsula, and it also used as a source drinking water for some urban areas municipality Amorebieta-Etxano. construction could pose potential risk to normal functioning aquifer, so its design included special procedure injecting cement microcement waterproof surrounding drilling, preventing from drain project initially an intensive characterization rock massif, well monitoring phase during works, which allowed real-time verification influence on restoration once works were completed. work carried out has shown that not caused significant impact