When an El Nino-strength storm caused an entire hillside to slump onto San Mateo County’s Polhemus Road in 1997, experts on San Francisco’s water system held their breath.

Just four feet under the road was a pipe that provided water to a million people in San Francisco and San Mateo counties. If that broke, as it appeared it was about to, not only would there be legions of thirsty residents to contend with, but an entire community would be flooded with snowmelt from the Sierras.

More than a decade after that crisis was averted, the Public Utilities Commission has approved an $86 million project to bury that mile of pipeline as deep as 200 feet under Polhemus Road — a depth at which seismic specialists say the new 8-foot concrete pipe will be safe from earthquakes and landslides, said Maureen Barry, a PUC spokeswoman.

The San Francisco Public Utilities Commission manages the water system that carries water from the Hetch Hetchy Reservoir on the western slope of the Sierra Nevada range to the Bay Area. Four pipes carry that water across the Bay, and they all converge at the “critical link” of piping along Polhemus Road, just below Crystal Springs Reservoir in the hills above San Mateo, before it is dispersed to San Francisco and northern Peninsula cities, Barry said.

This story continues below
Advertisement

Though many residents in the unincorporated neighborhood around Polhemus Road conceded that a fix was necessary, many opposed the PUC’s proposed project. Dozens of residents wrote to the PUC asking that other options be considered, options they hoped would mean less noise, traffic and dust in the neighborhood.

Claire Rosenburg, who lives near Polhemus Road, recalls the months her family had to live with the sound of trucks hauling away dirt from the 1997 landslide. She says she loathes the thought of coping with that noise and dust again.

“We’re going to be prisoners in our own homes, because we’re going to have to seal everything up,” she said. “It may be a necessary project, but there’s other ways they could have done it that weren’t so drastic.”

But some neighbors said they are glad the project has been approved. Kay McGough is a board member for the Odyssey School, which sits at the corner of Polhemus and Crystal Springs roads — one end of the mile-long project. Though she wrote a letter to PUC voicing her concerns about traffic congestion and noise pollution, she ultimately decided to support the project.

“All the noise and the dirt and the traffic are going to be a pain in the butt, but so is everything that means progress,” she said. “As a general rule, infrastructure in California and the Bay Area has been sadly neglected. We can’t just ignore it forever.”

kworth@sfexaminer.com