State taking an unusual approach to culvert replacement in Woodinville
Jul 21, 2016, 8:13 AM | Updated: 9:22 am
The state just started a new culvert replacement project in Woodinville, and contractors will be building something they’ve never built before: an underground bridge.
Crews will build a culvert for Little Bear Creek, which goes under SR 202, just south of Highway 522. The current culvert is too small and needs to be replaced.
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What makes this spot so unique is that the creek flows 30 feet under the road. Washington State Department of Transportation spokesperson Kris Olsen says it’s too deep for a typical culvert replacement.
“This one is so deep that we knew our usual approach wouldn’t work,” Olsen said. “Because we would probably have to close that road for a month or more.”
There also isn’t enough room to put all the dirt they would have to excavate.
“It’s a very tight space with businesses right in there,” Olsen said. “So it was an unusual location that required an unusual approach.”
The unusual solution was to build a buried bridge. That starts with creating what will be the sides of the new culvert, going in from the surface. That work began this week.
Contractors will have to close the road for one weekend, likely in early 2017, to dig out the roadway and the dirt, exposing the side columns being installed. They will lay girders on top, which will be the top of the culvert.
Once that’s done, workers will dig out the dirt from the creek side, up to those girders, exposing a 25-foot tall and 30-foot wide open area above the creek.
This is just one of the thousand or more culverts that the state must replace under a 2013 federal court ruling on fish passage.
