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WSDOT To Brief Seattle City Council On Emergency Viaduct Closure Plan

Elaine Thompson
AP Photo
In this photo taken Wednesday, Dec. 10, 2014, the Space Needle is seen beyond the Alaskan Way Viaduct as stands along the waterfront in Seattle.

The safety of the Alaskan Way viaduct will be back on the table Monday when the Seattle City Council will hear from the Washington State Department of Transportation about planning fora short- or long-term closure of the busy highway that runs along Seattle's waterfront. 

The questions come as the agency investigates recent sinking of the viaduct and nearby buildings and whether that settlement could be connected to the stalled Highway 99 tunneling project. The sinking coincides roughly with groundwater pumping for the access pit to the stalled boring machine known as Bertha. 

There is a plan detailing how to reroute the 85,000 vehicles that use the viaduct every day if it has to be closed. It includes sending traffic onto downtown surface streets and working with Metro to get more bus service in place.

The plan isn’t actually new. It’s been known for some time that when the tunneling machine passes beneath the viaduct, closure up to a month long will be necessary. But what if something unexpected happens and the viaduct is no longer safe? City council member Mike O’Brien says he’s been waiting for answers.

“And specifically when we talk about the viaduct, how safe is safe enough for them, and who makes the call when it’s no longer safe enough?” he said.

WSDOT says right now, the viaduct is safe. Although the roadway settled by more than an inch in November, engineers who have been taking daily measurements say it hasn't moved much since.

City council members also want to know who will be on the hook for the cost of measures such as extra transit if a sudden or lengthy viaduct closure becomes necessary.

Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to