A tunnel at Devil's Slide on Highway 1 could be built for roughly the same amount as an inland bypass, according to the long-awaited results of the tunnel study released Monday.
The average cost of building a 4,000-foot-long tunnel through San Pedro Mountain ranges from $131 million and $148 million, according to Woodward-Clyde, the engineering firm that performed the study. However, a modified version could be built for less, as low as $113 million, according to the study.
By comparison, an updated cost estimate for the Martini Creek Bypass, performed by the California Department of Transportation and released Monday, put the cost of the 4.5-mile inland bypass at $117 million.
Meanwhile, in a late development Tuesday afternoon, there were indications that the bypass cost estimate is likely to creep higher than the $117 million and that the tunnel estimate could still fall to $100 million.
Woodward-Clyde, CalTrans, the Technical Advisory Committee and the representatives of the Citizens' Advisory Committee met all day Tuesday in Oakland to go over the study with a fine-toothed comb. During the review, it was revealed that the tunnel cost estimates are "upper boundary" and could be expected to decrease as much as 10 to 15 percent as designs were fleshed out and estimates refined, said Tim Manzagol, a member of the Citizens' Advisory Committee who attended the Tuesday meetings.
"The bottom line is when you begin to look realistically at what the alternative is . . . you're looking at costs of $100 million or less."
Meanwhile, Manzagol said that the Technical Advisory Committee also had "a real question as to how real the $117 million is" for the bypass. Elements such as railings along the 4.5-mile bypass may have been omitted, which would increase the price tag.
At a well-attended public meeting Monday night in Pacifica, Ralph Trapani, a member of the Technical Advisory Committee, said a quick look at the study, which he had only received that afternoon, proved to him that a tunnel is feasible, both from engineering and cost standpoints.
"I think what we have here is a demonstration that the tunnel is feasible and prudent and should be continued to be looked at," Trapani said to an eruption of loud applause from the almost unanimously pro-tunnel crowd of about 200.
The statement capped a momentous day in the decades-old Devil's Slide debate. The closeness in cost between the tunnel and the bypass sets up a showdown on election day between the tunnel, represented on the ballot by Measure T, and bypass, which was approved a decade ago but has since been delayed by lawsuits.
On Monday afternoon, CalTrans held a hastily scheduled press conference in Foster City in an attempted end-around of "raucus" interruptions from tunnel supporters. There, the agency released the independent study and its own updated bypass cost estimates.
Everyone close to the tunnel study agrees that its findings are independent and trustworthy. Tony Caserta, the Federal Highway Administration's Washington, D.C. tunnel expert, described the study as credible, "thorough and professional" and "completely independent and unbiased."
Despite Monday's release, the complete tunnel study, which is more than 10 volumes, will not be available for about one week. But parts of it were presented Monday night.
Gordon Marsh, project manager for Woodward-Clyde, told Monday's audience in Pacifica that there is no question a tunnel can be constructed through San Pedro Mountain. However, poorer rock quality than was anticipated caused construction estimates to soar well beyond environmentalists' original estimates.
Seven different tunnel alternatives of varying widths were studied. Of those, option A, a double-bore tunnel with each bore measuring 29 feet from wall to wall and jet fans for ventilation, was shown to be the least expensive.
According to the study, a stripped-down version of that tunnel that would still meet federal tunnel construction standards could be built for as low as $112 to $144 million, depending on how bids come in. Of those, construction costs alone amount to $81.8 million and $108.5 million, respectively.
Another version of option A that included a full range of amenities, such as an extra sidewalk and different ventilation, would cost $117 million to $148 million.
The tunnel estimates include operation and maintenance costs for 35 years. Those are estimated at between $16 million and $20 million, much higher than CalTrans' estimates of operations and maintenance for the bypass. Among the costs for the tunnel is a one-time cost of $25 million to purchase a tunnel-boring machine.
On the plus side, Marsh reported, there would be "a nearly perfect balance" between the rock that would be dug out of the mountain and the amount needed to fill in a valley on Shamrock Ranch between the north portal and the existing Highway 1 alignment. Filling in the area, however, would destroy habitat for the endangered red-legged frog, requiring new wetland habitat to be created for the animal nearby.
Trapani believes option A could be even less expensive by removing a three-foot-wide sidewalk that may be superfluous. That would narrow each tunnel bore to 26 feet, reducing drilling costs.
The option A estimate also includes $3.4 million for a 31,000-foot-long upgrade of San Pedro Mountain Road to accommodate bicyclists and pedestrians traveling between Pacifica and Montara. That provision is unwanted by tunnel supporters and many bicycle enthusiasts, who instead want to see the existing Highway 1 roadway converted to a hiking and biking path if the tunnel is built.
CalTrans Project Manager Dennis Bosler said that is not possible because the road is continually sinking toward the ocean. "Nature wants that piece of rock bad," Bosler said, "and it's going to get it, sooner or later."
Tunnel supporters reject that, however, pointing to a study that suggests that the existing road would benefit indirectly from construction of the tunnel because some de-watering of the mountain would be installed to protect the tunnel.
According to both Marsh and Caserta, a tunnel could be expected to perform well, if not better, than outside roads in a major earthquake, a concern of some since the San Andreas fault would be four miles from the tunnel. Caserta, who has worked on tunnels for 40 years and is considered perhaps the nation's top tunnel expert, said "Experience has shown, tunnels - especially straight runs from portal to portal (as proposed for Devil's Slide) - hold up fairly well."
The completed tunnel study gives CalTrans 30 percent of a fully designed tunnel, thoroughness unmatched in a feasibility study. Caserta noted that most studies stop at 10 or 15 percent of a project's design. The 30 percent level would translate to saving as much as eight months in design time down the road if a tunnel is built, he said.
While the results of the tunnel study were universally welcomed, CalTrans' updated estimate for the bypass was greeted with skepticism, although tunnel supporters were clearly encouraged by the $117 million price tag.
Last year the bypass cost was estimated at $70 million. That did not reflect new environmental and seismic costs, such as lengthening bridges over newly discovered wetlands, that have now been incorporated into the bypass design, or a 35-year estimate for operation and maintenance to make it comparable with the tunnel.
Construction costs alone for the bypass are estimated by CalTrans at $86 million, and by an independent consultant checking the cost update at between $80 million and $92 million. Specifics of the bypass update were unavailable Tuesday, but will be available next week, said CalTrans' Bosler.
While tunnel supporters were upset with CalTrans' Monday afternoon press conference, they were jovial and effusive in their gratitude for Bosler's presence - as well as that of Marsh, Caserta and another FHWA representative, John Schultz - at Monday night's meeting in Pacifica. In July, CalTrans refused to attend a public forum, igniting a storm of criticism.
"This has gone a long way to establish trust in the community," said Zoe Kersteen-Tucker, spokeswoman for the coalition of environmental groups supporting Measure T. Some observers at Monday's meeting even praised Bosler, saying it appeared he was trying to answer questions from the audience in a helpful and courteous manner.
One of only a handful of Measure T opponents at the meeting questioned supporters' assertions that a tunnel can be built "Sooner. Safer. Cheaper," which is Measure T's campaign slogan. Bosler said that he sees "no clear advantage" to either the tunnel or bypass in terms of the time it would take to construct.
No new ground was broken on the continuing question of tunnel funding. The FHWA's Schultz said Congress would have to appropriate funds.
According to Caserta, the next step for the tunnel study is for the staffs and administrators at CalTrans and the FHWA to study it. That will lead to a determination that the tunnel is or is not a feasible and reasonable alternative. If it is determined to be a reasonable alternative, then a supplemental environmental impact report would be prepared for the tunnel. That will not happen before the election, however, Caserta said.
CalTrans projects the conclusion of the supplemental environmental impact studies for the bypass and, if it is included, the tunnel, in March. At that time, federal regulations surrounding the Clean Water Act and Endangered Species Act will require that the "least environmentally damaging practicable alternative" be built.
In an interview Monday, Caserta said "tunnels compare favorably" against open roads in terms of environmental impacts.
Executive summaries of the tunnel study and CalTrans' bypass cost estimate will be available to the public without charge. The complete tunnel study will be available for review at libraries. Because of its size, it will also be sold by Woodward-Clyde for an as-yet undetermined price. To receive a copy, contact Colin Jones at (510) 286-5776.
Monday night's meeting, which lasted four hours, will be broadcast tonight, Oct. 9, on Mid-Coast Television, Channel 6, beginning at 7 p.m.