Santa Clara Valley Water District (Valley Water) has announced the completion of the construction of the last stretch of a 1,736-foot tunnel adjacent to the Anderson Dam in Santa Clara County, California. By using a specialised micro-tunnel boring machine (TBM), construction crews drilled the final 347ft, reaching depths of 30ft below the water’s surface. Last month, divers and crane operators removed the TBM, lifting sections of the machine using a large crane. Although the tunnelling work is complete, additional tasks remain before dam construction can commence, said the California public agency responsible for managing the water resources in Santa Clara County. Valley Water is preparing the downstream creek channel to accommodate increased water flow from the new outlet tunnel and is installing a structural lining inside the tunnel to ensure added support. The Anderson Dam tunnel project is part of the larger $2.3bn Anderson Dam seismic retrofit project. Upon its completion, the new, larger tunnel will increase Valley Water’s capacity to release water from the reservoir in emergencies, enhancing the dam’s safety measures.