Don’t Worry, It’s Probably Nothing
[ Excavation at 505 1st Ave; photo: Scott Durham ]
What fun it must have been excavating the 4-story underground parking garage for the new Starbucks building at 505 1st Ave S, as shown in the photos (thank you Scott at CD News). The spectacular mess they encountered—reportedly extending down as far as 40 to 50 feet—is typical of the fill that is found along the south waterfront, west of 1st Ave. It consists of leftover debris from the historic sawmills, along with the remains of the piles that once supported the piers and overwater railroad tracks that were built when the area was still a tidal flat.
The latest plan for the deep-bore tunnel moves the alignment from 1st Ave to Alaskan Way for the section south of Yesler Way. Which means the tunnel now has to traverse a massive underground heap of that unruly fill for about five city blocks.
Worth worrying about? Dunno. Perhaps deep-bore tunnel machines eat that kind of fill for breakfast. Perhaps the tunnel will be deep enough to go under it, and perhaps chewing a 54-foot diameter hole can be done without disturbing unstable fill above. Any experts out there care to weigh in?
If nothing else this a good example of the unanticipated complexities that inevitably arise when a mega-project starts to get real. For a good reality check on the potential challenges facing the deep-bore tunnel project, see Cary Moon’s recent Crosscut piece.* And this is why megaprojects so often go over budget. And this is why being on the hook for cost overruns matters.
But the bigger question this all circles back to is this: Why are we taking on the huge risk and expense of a piece of mega-infrastructure we don’t need?
[ Excavation at 505 1st Ave; photo: Scott Durham ]
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*Annoyingly, though alas, not surprisingly, the Crosscut editors headlined Moon’s piece “Tunnel Worries,” thereby framing it as the emotional ramblings of an amateur rather than what it actually is—that being serious analysis by one the City’s most knowledgable experts on the viaduct replacement issue.