Seattle’s planned deep-bore tunnel could get even more contentious soon. As state engineers flesh out their early cost estimates, a comparable tunneling project has hit another snag. The Seattle Times reports:
The Brightwater sewage-treatment project, which is costing local ratepayers $1.8 billion, is delayed yet again because fixing a damaged tunnel-boring machine stuck deep underground will take months longer than originally thought.
This should be eye-catching because Brightwater’s sewage tunnel construction uses a smaller-scale but very similar tunneling technology to what is planned for the tunnel under downtown Seattle. And the Brightwater tunneling project has encountered numerous problems.
Earlier this year, both machines working on the two “Central Tunnels” were damaged and await repairs underground. The one that was due to be operational by November is, apparently, in worse condition than originally believed. The other is not due to be fixed until December or early 2010.
So the project will be delayed further and the costs will continue to mount:
The delay likely will push completion of the project—originally scheduled for 2010—into 2012, project manager Gunars Sreibers said Tuesday.
It isn’t yet known how much repairs will cost and how much of the cost might be paid by the county, the contractor or the manufacturer of the damaged machines, but, Sreibers said, “We’re in the tens of millions of dollars of money at issue.”
If Seattle’s deep-bore tunnel were to encounter similar problems, it could pose a serious risk for Seattle property taxpayers, who are designated by state legislation to pick up the tab for any cost overruns. The legality of that legislation has been much disputed, but at least one influential legislator has vowed to enforce the provision. (At best, the current funding legislation does not adequately clarify who pays for cost overruns, a potentially serious problem.)
Amplifying the worrisome lessons from Brightwater, the deep-bore tunnel project’s costs were first estimated when the project’s design was considered only 1 percent complete. (Today, the project is considered to be 5 percent designed, but the state has declined to release updated cost estimates until it is 15 percent designed.) None of this is good news, but the Brightwater experience is, unfortunately, consistent with the majority of major tunneling projects undertaken in the area, a topic I covered in a recent report for Sightline, “Cost Overruns For Seattle-area Tunneling Projects.”
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But I also have at least a partial defense of the Brightwater project. In the course of writing the report, I looked into the cost estimates for Brightwater in some detail and I concluded that the media has not been entirely fair. For example:
The existing $1.8 billion tab for the project is roughly double what the Metropolitan King County Council was told when it first approved the project.
That implied 100 percent cost overrun is technically true, but it’s also misleading. Here’s a fuller description that I included in the report:
According to newspaper accounts, the projected cost of the total Brightwater project—including a conveyance system for transporting sewage underground, a marine outfall system, and a new wastewater treatment facility—has already exceeded its initial estimates by more than 100 percent. However, this figure is based on an early cost estimate from 1999 of approximately $880 million, which in turn was based on a conceptual design of a wastewater system, without taking into account the actual length and route of the tunnels, the actual cost, or inflation. Cost estimates released in 2004, when the project design was 30 percent complete, established a higher budget baseline that accounted for actual design and siting choices, as well as inflation for materials and labor. Using these updated figures, the total Brightwater project is, at most, 24 percent over budget. [Update 11/20/09: More precisely, I mean that the project’s current projected expenditures are, at most, 24 percent higher than the budget approved as the official baseline in 2004.]
And the County Council has approved the higher expenditures for the project.
Additionally, the Brightwater project managers deserve credit for being forthright in a way that some other public agencies are not. The public gets to see annual reports and monthly project updates plus annual quarterly audits. Their community relations officers are informative, engaged, and committed to keeping the public apprised. It’s only because of their diligence and accountability that the media has any realistic view of the project’s difficulties.
Unfortunately, my experience to date leads me to believe that we should not expect a similar level of openness from officials working on Seattle’s deep-bore tunnel.
Eric – I think the Beacon Hill Light Rail tunnel used a similar tunnel boring machine. Except for an unexpected encounter with sand, I think that machine performed pretty well.Tunneling is a crapshoot any way you look at it, though.
Eric de Place
You’re right, Ryan. The Beacon Hill tunnel boring machine was also similar to what’s proposed for underneath downtown and it didn’t encounter any major problems. But even so, that tunnel still ran at least 30% over budget. More here: http://www.sightline.org/research/sprawl/res_pubs/cost-overruns-for-seattle-area-tunnel-projects/tunnel_report.pdf
The most structurally stable Seattle seawall and waterfront plaza and boulevard are only possible with the option of a cut/cover box which coincidentally handles traffic much better than the Deep-bore. Why can’t Sightline columnists admit to these more severe shortcomings of the Deep-bore? The some 40,000 vehicles that the Deep-bore will displace onto the new Alaskan Way boulevard will produce gridlock there and along the thru-corridor Mercer West project, additional traffic (including freight) will significantly degrade air quality there. Fire Grace Crunican and don’t let her work in any department of transportation anywhere ever again.
One possible reason for the better PR: Costs associated with Brightwater are *much* more visible to anyone who has to pay a sewer bill in King County. My bill, for a household of 2, is $75 and we’re on the low end of the consumption spectrum. In the city of Bellevue, the bills are sure to inform the customer that most of that money goes to King County for sewage treatment.If only the costs for driving and truck delivered goods were as visible to the consumer….
There have been tunnel troubles in bored twin tubes for moving water between a reservoir and a filtration plant in North Vancouver, BC.The first contractor fired; a replacement contractor on the verge of being hired. $220 million more added to $600 million … a 37% bump up.Why twin tubes you ask? Answer, the water has to make a round trip—unfiltered water in one direction, and clean filtered water coming back.More than you want to know at:http://www2.canada.com/northshorenews/news/story.html?id=bb6394ea-da0a-4775-80df-f314cf091571andhttp://www.joconl.com/article/id31418
1. The Central Tunnel TBMs use pressurized slurry to hold back the groundwater, which will reach over 6 atmospheres of pressure. I think this is the type of TBM being proposed for the Alaksan Way tuunel.2. The Beacon Hill project faced much lower water pressures. As a result, its TBM used a different ground support system called Earth Pressure Balance. The technical issues with EPB machines are fewer in number and much less complex than with slurry machines, especially slurry machines at high pressures.3. The project mentioned by John Niles is the Seymour-Capilano job. That drive is going through solid rock so it uses a machine of an altogether different type than either slurry or EPB. One major difference is that in solid rock, there may be water flows but the machine does not have to hold up the earth itself that is pressurixed by groundwater as is the case in the soft ground conditions through glacial till that we have in Seattle.The key takeway here is that in fact there is no valid comparison among the three jobs and three different machine types. The critical metric is groundwater pressure in conditions of soil rather than solid rock. By extension, the critical objection to the Alaskan Way tunnel at this time should be: what is the relation between ground type (clay, sand, cobbles, mixtures of the three?) and groundwater pressure? Until a thorough geologic study of ground conditions is done, the project must be opposed. It was idiocy to approve the job and fund it without knowing having this study done and circulated.