Officials lauded the project as a major improvement for the South Bay's water supply and a significant job creator.
The Bay tunnel groundbreaking event was held at the bayside site at 5000 University Ave. in Menlo Park, near the approach to the Dumbarton Bridge, where the project will begin with the digging of a shaft 141-feet deep and 58 feet in diameter.
Dozens of hard-hat-wearing project managers, agency leaders and city officials attended the groundbreaking to express their support.
The Bay tunnel is part of a $4.6 billion rebuilding of the Hetch Hetchy water distribution system for the Peninsula, South Bay and San Francisco, designed to make water delivery more secure in the event of a major disaster, such as an earthquake. The system is run by the San Francisco Public Utilities Commission.
The tunnel will have 3-foot-thick watertight walls and a 12-foot-thick concrete floor slab.
"It means life and death on the Peninsula," Menlo Park City Council Member Kelly Fergusson said of the water project.
The 5-mile-long, 15-foot diameter tunnel will secure water delivery to the Peninsula by replacing the current water pipelines that cross the Bay. The old pipelines were built as early as the 1920s and 1930s and have been identified as seismically vulnerable by the Public Utilities Commission.
Art Jensen, CEO and general manager of Bay Area Water Supply and Conservation Agency, said the project is "replacing an aging but vital lifeline."
Ed Harrington, general manager of the SFPUC, said, "We are very proud that this project is creating jobs."
Other speakers at the event were Julie Labonte, director of the commission's Hetch Hetchy Water System Improvement Program; Bill Nack, business manager of San Mateo Building Trades and Construction Council; and Sharon Williams, executive director of JobTrain in Menlo Park.
Mr. Nack said the event was a celebration of the employment of hundreds of men and women who are out of work. The project will require 575,000 building hours.
"When a community is given a chance to let local residents benefit, it's wonderful," Ms. Williams said.
Bob Mues, the project's construction manager, said the SFPUC is trying to organize a local job-training program for union members, so they can work on the project. He said there will be some surface jobs for job trainees but that most of the underground work requires skilled workers.
After the remarks, attendees were bused 300 yards to the groundbreaking site, where three muddy workers were waiting with an 80-foot tall digging crane.
They lowered a large "clam bucket" on the end of the crane into a water-filled crevice. It took minutes to reach the bottom and be brought back to the surface. But then the clam bucket surfaced, spewed muddy water and dumped its contents.
"One bucket at a time," East Palo Alto City Councilman Rubin Abrica said, laughing.
A 300-foot-long tunnel boring machine, to be manned by 12 to 15 workers, is being custom-made in Japan for this project. The $15 million machine will arrive on the site in summer of 2011.
Mr. Mues said while there will be a shaft on the other end of the tunnel in Newark, the shaft in Menlo Park will be the entrance for the boring machine, workers and all supplies.
When the tunnel is near completion, workers will still be entering through the shaft in Menlo Park. Workers will then have to make a 4-mile underground commute to the other side of the tunnel on small trains called "locis."
The project is expected to be completed in 2015.
Go to sfwater.org/baytunnel for more information on the project.