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San Francisco Chronicle
South of Pacifica, the infamous precipice known as Devil's Slide perpetually mocks all efforts to tame it. But engineers are finally poised to master the troublesome stretch of Highway 1: A streamlined solution known
as The Tunnel appears to be forcing its way into reality. There aren't many places in the Bay Area where geography is such a constant source of anxiety as it is on San Mateo County's Coastside. When the winter rains
arrive, residents hunker down. The worry is that the two-lane highway will wash out once again. If that happens, Coastsiders might start feeling like they're living on the Farallones -- because the only way out will be
Highway 92, itself a delicate mountain road already vulnerable to long traffic jams. Now, however, the planners and environmentalists who have wrestled with the tunnel idea for more than a decade say that the money is
available and the right-of-way precisely identified. And last month, an engineering firm was selected to put together a final design of the nearly mile-long tunnel. Engineers are calling it one of the "largest and
most technologically challenging projects" in the Bay Area in decades. "It's really moving along now," said Skip Sowko, Caltrans project manager for the tunnel. "The environmental documents are basically
complete and we expect federal approval in a couple months or so. Then it's off to the races." The timetable for the $165 million project calls for two years of design work and three years of construction, meaning
that Coastsiders will have to endure at least five more winters of discontent before they can stop worrying about falling into the ocean. But for many Coastsiders, that's a blink in time, particularly when they think of
the more than 60 years they -- and their ancestors -- have had to put up with Devil's Slide's bad moods. "People are relieved to finally see some real progress after all these years," said Zoe Kersteen-Tucker, a Moss
Beach resident and president of the Committee for Green Foothills, one of the leading organizations that fought for the tunnel. "Still, when the tunnel is finally completed, I think many of us will be astonished when they see
the size of the project and the magnitude of what we have done. After 10 years, people will look back and see this as a huge environmental victory." Caltrans has long been aware that Highway 1 at Devil's Slide is
geologically unstable. Since the highway was built in 1937, Caltrans has tried several "permanent solutions," including drainage schemes, pavement reinforcement and rock anchors. Nothing worked for long. Between 1973 and
1983 the road was closed 22 times. In 1980 the road was closed a total of 238 days. In 1982-83, winter storms closed the road for three months. In the early 1970s, the Sierra Club and several other organizations filed a
lawsuit over Caltrans' proposal to build a 4.5-mile bypass right through the McNee Ranch area of Montara State Beach. A U.S. District Court halted construction pending more environmental reviews. A lot more. But the worst
was still to come. In 1995 winter storms again eroded the roadbed, forcing its closure for six months. Businesses collapsed, the tourism industry dried up, families and public officials squabbled over long commute times.
Tunnel advocates hit the streets and rural roads, collecting more than 34, 000 signatures to place Measure T on the county ballot. It was approved overwhelmingly in November 1996 as an alternative to the bypass highway plan
that had been bitterly opposed by environmentalists for years. Last month, Caltrans selected HNTB Companies, a firm in Irvine, that specializes in tunnel, bridge and seismic retrofit projects to design the tunnel. Although
the rough outlines of the tunnel project have already been hammered out, HNTB expects to begin the detailed design work in February or March, after all environmental studies have been completed and the Federal Highway
Administration gives the final go-ahead. The project includes the tunnel -- actually two tunnels, one lane in each direction -- and two approach bridges at the north portal over Shamrock Ranch, located about one mile south of Linda
Mar Boulevard in Pacifica. The approach bridges, required as part of mitigation to protect endangered red-legged frogs in ponds below, will be 1,000 feet long and about 120 feet off the valley floor of Shamrock Ranch. To
Dana Denman, whose family has owned the Shamrock Ranch since the late 1930s, the specter of a tunnel and bridges going right through her property -- 14 acres of her 286-acre ranch -- is something she has anticipated with mixed
emotions for years. "No matter what they do, it will affect us," said Denman, 52, who boards horses, cats and dogs, and also trains dogs in the ranch's sylvan setting. "I am a little concerned about noise, and
also the fumes from the cars. It's going to be different, but this is so much better than the original bypass project they had in mind. That thing was so huge it would have taken a third of my ranch, with cuts in the mountains so
deep you could have fit the Queen Mary or San Francisco City Hall in them." The twin 30-foot-wide tunnels will be cut through San Pedro Mountain and will be absolutely straight, sloping from the north slightly
downward toward the southwest where it will rejoin the original Highway 1, well south of Devil's Slide. There will be no designated bicycle lanes in the tunnel, although each bore will have two 4-foot-wide shoulder lanes
on either side that bicyclists can use if they insist. For safety reasons, Caltrans prefers that bicyclists use the existing right of way on Highway 1, which will be used only for hiking and biking when the tunnel opens.
Inside both tunnels, cross passages connecting the two bores will be constructed at 500-foot intervals, in case of vehicle accidents. About 30 jet fans, each three feet in diameter, will be installed, operated remotely by
computer systems to control air quality. Originally, some Caltrans engineers were discussing the possibility of using a custom-made tunnel boring machine that would carve out a 30-foot diameter section of each tunnel. But
more recent studies indicate that cutting through San Pedro Mountain the old-fashioned way -- using dynamite and other explosives -- is the best way to go. Most of the 674,000 cubic meters of excavated material, a mix of granite
and shale and other sedimentary rock, will be dumped at a disposal site near the south portal. Other dump sites are being considered near Highway 92 or in Pacifica. Caltrans insists that dumping activities will affect traffic
minimally, if at all, because it will be done in off-peak hours. "This is certainly one of the largest and most technologically challenging projects in the Bay Area, that's for sure," Marsh said. "The only thing
comparable is the Bay Bridge retrofit project. And for this we need to drill and blast." The California Coastal Commission recently gave its nod of approval to the project, concluding that it is consistent with the
Coastal Act. "The tunnel is going to be an incredible project," said Mark Delaplaine, federal consistency supervisor at the California Coastal Commission. "By going under McNee Ranch, it saves the park. It's kind
of a miraculous fantasy coming true." There are still environmental concerns, however. Biologists at the federal Fish and Wildlife Service have been working with Caltrans for more than two years studying how the
tunnel might affect the red-legged frog, said Ken Sanchez, a senior biologist in the endangered species division. "We believe Caltrans is avoiding and mitigating the impacts on the red- legged frog to such an extent that we
don't have a problem with the alignment, " Sanchez said. "We expect in the next two or three weeks we will issue a biological opinion. . . . They have really been going the extra yards to protect the frog."
Still, not everyone loves the tunnel. Oscar Braun, a Half Moon Bay area resident, has been battling the project in the courts off and on almost from the day the idea was conceived. "In north portal area, the initial
plan for the tunnel was that there was not to be any fill of the wetlands or any bridges," said Braun, executive director of Save Our Bay Foundation, a nonprofit organization that does marine and watershed conservation work.
"The bridges in the plan now actually create just as much damage because they will put the frog ponds in shadows all day, lowering the temperatures and have an impact on egg laying." But the best part of the
tunnel project for some is what it replaces: Highway 1 at Devil's Slide. The mile-long stretch of treacherous highway will become one of Northern California's most spectacular trails for hikers and bicyclists, and a link to other
Coastside trails. "It will be a great example of experiencing the benefits of slowing down and observing nature from a spectacular perch known as Devil's Slide," said Barbara Vanderwerf, author of several books on the
history of San Mateo County and the Coastside. "It is a gift to the people of the United States, that mile, and I plan to walk it to count every bird, observe every plant, see every piece of rock and shale.
Page last updated November 4, 2001. |
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