The Alaskan Way Viaduct would be replaced by a tunnel under an agreement reached between the state, King County and the city of Seattle.

Share story

OLYMPIA — The state and local governments have agreed to replace the Alaskan Way Viaduct with a tunnel under downtown Seattle, Mayor Greg Nickels and Metropolitan King County Councilmember Dow Constantine confirmed today.

The agreement between the state, King County, the city of Seattle, and the Port of Seattle is expected to be formally announced Tuesday.

The state would cover the cost of the two-mile tunnel, with the city and county picking up the tab for surface-street and transit improvements. The port would be involved as well, but details are still sketchy.

The total cost is expected to be around $4.25 billion, with the state’s share totaling $2.8 billion, according to a source close to Gov. Chris Gregoire. The city’s part of the deal would be just less than $1 billion, Nickels said. It would cover repairs to the sea wall, street improvements and possibly a streetcar line, he said.

“The burden is going to be on the city and county to provide some of the other surface and transit improvements needed to make local transportation work,” said Constantine, D-West Seattle. “The big questions will be, how quickly can the tunnel get built, how long can the viaduct reasonably last and is there a gap between those two dates?”

The tunnel would be bored beneath the western edge of downtown, under First Avenue, which might allow the current viaduct to remain in use during tunnel construction.

Nickels said the city’s share of the money would come from a variety of sources, including a local taxing district. He also said he hopes the federal stimulus package expected from Congress would include some money for the project.

Constantine said counties also have a local car-tab tax at their disposal.

The county was already searching for new money to replace stagnant sales taxes that threaten to cripple King County Metro Transit. He said he hopes state and local governments can figure out how to take care of that revenue shortfall and the viaduct replacement at the same time.

Nickels has supported a tunnel for some time.

“My goal has been to open up the waterfront,” he said, “and this will do that.”

The agreement reached between the state and local governments calls for a four-lane tunnel that would start at Royal Brougham on the south end, travel under First Avenue and emerge near Thomas north of the Battery Street tunnel.

In December, the state, city and county came up with two finalists for viaduct replacement: another elevated highway like the existing viaduct and a surface “couplet” in which southbound traffic would run on Alaskan Way and northbound traffic on Western Avenue.

But since then, several of the viaduct “stakeholders,” a group of residents, business people and environmentalists brought on board to advise the city, county and state, said the tunnel should remain on the table.

There were strong indications last week that that’s the direction Gregoire was headed.

One advantage of the tunnel is that the viaduct likely would remain in place while the tunnel is being built.

Mike O’Brien chairman of the local Sierra Club chapter, said he opposes the tunnel because it is too expensive and would do nothing to reduce greenhouse gas emissions. He’s supported surface street improvements and additional transit to replace the viaduct.

“Sierra Club’s objective is to make changes in investments in transportation superstructure. To spend a couple billion to build an underground highway along the waterfront only used for automobiles is the wrong type of investment to make right now,” O’Brien said.

“The governor, mayor and executive turned their backs on global warming.”

The decision over replacing the 55-year-old viaduct, damaged in the 2001 Nisqually earthquake, has been through years of controversy. Two years ago, city voters rejected both a tunnel and an elevated highway as replacements for the viaduct.

The state and city then decided to replace the noncontroversial south end of the viaduct, and put off a decision on the central waterfront portion.

That work is peeling off more than $1 billion of the $2.8 billion set aside by the Washington Legislature, leaving some people to question whether the remaining money is enough to build tunnel. However, the governor’s office says it expects the tunnel can be dug for $1.6 to $1.8 billion.

King County Executive Ron Sims has advocated using surface streets and increased transit to replace the viaduct.

His office had no comment this morning, and said he would wait for the governor’s announcement Tuesday.

Staff reporter Susan Gilmore contributed to this story.