At Crosscut, Doug McDonald has a fact-dense piece on the travails of the Brightwater sewage system bored tunnels. The upshot is that things appear to be getting more difficult—and even more costly—than everyone had hoped:

Metro King County’s Brightwater sewage treatment plant tunnel is a project in a very awkward fix. There is a big problem with a contractor and its crippled tunnel boring machine on one of its essential tunnel contracts. All this carries lessons and warnings for the future waterfront tunnel to replace the Alaskan Way Viaduct…

It’s an understatement to say that Doug is extremely knowledgeable about tunneling projects, so his perspective is a very valuable one. (Doug is also a Sightline Fellow, though he did not write the Crosscut article under Sightline’s auspices.) Go read it.

To me, the Brightwater experience is an important cautionary tale from right next door. Bored tunnels are a tough business where you should expect the unexpected. So the difficulties are a glaring reminder that Seattle’s deep bore tunnel should have a clear agreed-upon plan for cost overruns — just in case things don’t go as intended.


4/15/10—Fun Update! There’s a new lower-than-expected bid for an above-ground interchange south of the downtown tunnel. Going unreported so far is that the lowest bid, and therefore the winner, is Skanska USA, which is actually a joint venture that includes none other the Vinci Construction, the contractor responsible for the stalled Brightwater project.