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 ]

>>>

*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.

10 Responses to “Don’t Worry, It’s Probably Nothing”

  1. Doug

    One thing that keeps rattling me about this cost overrun issue as a reason for not building the tunnel is that that surface alternative is, by all accounts, also a megaproject, and quid pro quo, equally likely to incur cost overruns. So, the fact there could be cost overruns is a negative of both alternatives, although for now, the tunnel is only one of the two that COS residents are on the hook for.

  2. Wells

    The Surface/Transit alternative, Doug, would start with rebuilding the seawall and a temporary surface boulevard (the wide plaza would come later) to accommodate SR-99 traffic when the AWV is closed permanently.

    A new bridge over the railroad tracks at Broad Street should be in place at that point. The AWV is then removed, streetcar tracks, everything removed, and building from the east side, the new Alaskan Way builds up next to the temporary boulevard. Then the completed Alaskan Way opened, the Seawall plaza and Lower Belltown segment from the waterfront to Western/ Elliott and the Battery Street Tunnel are built.

    The Surface/Transit alternative construction should not incur the kinds of uncertainties and cost overruns predicted with either the Deep-bore or a Cut/cover tunnel. It’s the least expensive option but entails the most difficulty handling traffic during construction.

    The 4-lane Cut/cover has less difficulty handling traffic because the AWV will remain in place up til the last year or two of construction. During those years, SR-99 traffic (from the north) will be diverted over the new bridge at Broad Street onto north Alaskan Way and enter the completed cut/cover portal at Pike.

    It’s likely the current 4-lane Alaskan Way surface boulevard design will be rejected. The 4-lane design cannot handle the predicted amount of vehicle traffic that the Deep-bore will redirect there. There’s no way. It’s likely a 6-lane version will be recommended instead, but it too won’t handle the traffic. There has to be a way to divide thru-traffic from motorists looking to park.

    Pre-Crunican designs incorporated a 2-lane frontage road on the eastside. Those designs should be reconsidered. The frontage road reduces the width of the Wide Plaza, but respected architects say the wide plaza is disproportionate to a working waterfront. The frontage road would line up perfectly with Railroad Ave. The ‘island’ between it and a 4-lane Alaskan Way could reproduce the current streetcar/bicycle/pedestrian corridor, only nicer.

    The Deep-bore south portal will be cut/cover construction for several blocks. The Deep-bore and the 4-lane Cut/cover tunnels have roughly the same south portal design.

  3. wes kirkman

    Doug, read Dan’s post again. He makes a good point about how the project involving tunneling makes it more likely, not equivalently, to have cost overruns. In fact, construction bids are seriously under estimates right now…we could probably save money on a surface option.

    If you want something suspect about the argument, question why most (I’m guessing) of us anti-tunnel-ites (not excluding myself) would be cool with spending that money on more rail transit tunneling.

  4. Mark S Johnson

    All good questions about the cost overrun issue.

    I thought I would just say that the issue of boring through the fill is also a good question, althoudy debris is not much of a problem for those machines. When the Kingdome was built, they had trouble driving piles through rail cars that were part of the fill.

    As it happens, I think that most of the area south of Yesler would be cut and cover- that is the area where the would dig the hole to put the machine into the ground before is starts digging. All pretty academic if you are opposed the expense in the first place, I realize.

  5. Ross

    Personally, I don’t like tunneling in general. I think it is too expensive. I don’t like surface rail either, because I don’t think it goes fast enough. I like elevated rail. It is usually just about as cheap as surface rail, but way faster. It works well for Chicago. I sure wish the rail line from downtown to the U district was above ground (it would have made for a very pretty ride). Of course, this is another reason why I wanted the monorail so much. Suddenly those condos in Ballard become really, really hot property (take the monorail downtown or to West Seattle and enjoy million dollar views along the way).

    So, I guess I don’t like tunneling for cars because I don’t think we should spend the money and I don’t like tunneling for rail because I don’t think we should spend the money and because I think the ascetic experience of the rider is very important.

  6. Monk

    ascetic /əs’etɪk/
    Synonyms:

    * adjective: austere
    * noun: hermit, anchoret

    Yes, the experience you want for the rider does sound very ascetic.

  7. Joshua Daniel Franklin

    The bright interior lights in Link almost gave me a transcendent religious experience on the way back from SeaTac last night. Unfortunately they also ruin the million-dollar view at night. I’d prefer asceticism on the lights.

  8. Ross

    Monk — Thanks for catching my typo. Obviously, the word I meant to type is “aesthetic”. Usually, FireFox catches my typos, but not when it happens to be a different word. Too bad you can’t edit these comments.

  9. Darrin

    Let’s hope they have a good cost control manager in place to mitigate the risks and keep management well informed.

  10. Still Not Digging The Tunnel | citytank

    [...] 01.10.10: Don’t Worry, It’s Probably Nothing [...]

Leave a Reply