under the streets part II

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The underworld is traditionally a place of mystery, the abode of the dead and the faery folk. Aside from the supernatural, we don't really know what lies deep under Seattle. That's why this geotech firm was taking borings before the start of designing the deep bore tunnel that was approved to replace the Viaduct. In loose terms, Seattle sits over a bowl of glacial fill, unstable in earthquakes, but more specific information is needed for tunnel placement.



I don't like big expenditures for auto infrastructure but don't really mind this new tunnel, even though the cost projections are hugely expensive and there are likely to be huge overruns (on an encouraging aside, Link light rail is 138 million under budget). The tunnel will route freight and auto through traffic off of our waterfront and downtown surface streets. My hope is that the tunnels two decks will be constructed so that one day rail traffic could be carried through it. Or perhaps it could be abandoned altogether (an expensive abandonment) once it has served its purpose. This Battery Street tunnel will be closed when the new tunnel is in place and the Viaduct torn down. They say this cut-and-cover tunnel will be filled in, but I'm not sure how that would be done. Maybe it will just be blocked off, like the ghost stations of the London Underground.



The Great Northern (now BNSF) rail tunnel was dug by hand in 1904 and still routes freight and passenger rail under the city. It was hugely expensive for it's time with costs of $1.5 million. The two railroads that originally used it paid for it's construction, at the city's request, for the purpose of clearing and beautifying the streets of an ambitious city with great aspirations.



The Metro Bus Tunnel, or more correctly, Transit Tunnel, is a double-bore tunnel 60 feet below downtown Seattle. Completed in 1989, it came in at about $455 million in cost. The bores were large enough to someday accommodate rail. In fact rails were laid when the tunnel was constructed, but had to be replaced during the 2005 to 2007 retrofit for Link light rail, which will open this July 18th. Both rail and bus will operate in the tunnel; after observing a southbound stoppage on Friday when an ST bus broke down, I am wondering just how well that will work. The point is, though, that it was forward-thinking all along.



The "Seattle Process" is often blamed for blocking progress, but I don't think this was always the case. After Seattle burned in 1889, city leaders made plans to rebuild the city for better infrastructure function, i.e. plumbing and transportation, leading to the regrading of the street levels. Business owners couldn't wait, and rebuilt at the existing street levels while the new street construction was taking place, with results that you can see and hear about on the Underground Tour. You can't stop progress, but you can progressively adapt to it when the stages don't quite mesh. That's why I'm not too concerned about our expensive new tunnel.




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