A $2-billion deep-bore tunnel along Seattle’s downtown waterfront appears to have overcome what may be its final obstacle to construction, garnering the approval of nearly 60% of voters in a referendum on whether the city should give the notice to proceed with the project.
The tunnel, scheduled for completion in 2015, is the centerpiece of a $3.1-billion Washington State Dept. of Transportation program to replace the seismically suspect double-decked Alaskan Way Viaduct. That thoroughfare carries approximately 110,000 vehicles each day along one of Seattle’s primary north-south arteries. Damage from the 2001 Nisqually Earthquake sparked a decade-long, often-controversial effort by WSDOT to find a suitable strategy for replacing the Viaduct and the aging seawall that supports its backfilled foundation soil.