AFTER: The site of the March 13, 2017 debris slide on Route 503 following completion of its stabilization earlier this year.
BEFORE: The scene on Route 503 following the March 13, 2017 debris slide that closed the road and started a yearlong project to stabilize the hillside.
Route 503 near mile post 38 is now back in full service following a protracted repair and stabilization project to keep a 20-million-pound rock from crashing down.
The project to stabilize the hillside completed in January, with repaving and restriping complete late last month, marking a year of work following a March 13, 2017 debris slide that occurred.
From the outset the slide didn’t appear to be anything out of the ordinary until the first crews got to the scene.
“When our crews who responded initially got out there, they could still hear cracks, rocks cracking, and tree roots, massive tree roots snapping,” Washington Department of Transportation (WSDOT) Spokeswoman Tamara Greenwell said. With signs that the scene was unsafe, the agency had to resort to other techniques such as Light Detection and Ranging (LIDAR) imaging and drone photography to assess the situation.
“For weeks we were not able to get traditional tools up on the hillside to check it out,” Greenwell said.
Prior to blasting to stabilize the slab, Greenwell said workers rappelled down its face with hand tools to remove loose pieces of rock.
About a month after the slide, blasting work to stabilize the slab began, and by May a single lane was opened for transit. In August a second phase of the project began to anchor the rock wall, finally concluding in January.
Ultimately for construction, geotechnical analysis and permitting altogether was nearly $3.85 million, far above initial estimates closer to $1 million. Both Greenwell and WSDOT Project Manager Brad Clark spoke on how unique the slide was in comparison to the more routine dirt, soil and tree debris slides.
When the project was handed to him Clark said it was expected to take 30 days, though by the end of that timeframe it became evident there was much more work to be done. Once workers were able to start removing some loose rock it was determined that the rock was more fragmented than initial estimates, requiring additional anchoring and removal of some more rock.
“Once we start peeling the rock off the face … we don’t always know what we are going to find,” Greenwell said.
While the project was underway Greenwell said WSDOT took multiple avenues of outreach with the local community, addressing the transportation needs of businesses as best they could while also keeping residents in the loop about what the project would entail.
“When we posted that it was done we got a lot of notes of appreciation from folks who were thankful for the outreach work that we did, who understood that this wasn’t your typical slide,” Greenwell remarked.
