Bay Tunnel, The First Tunnel Under San Francisco Bay, Begins Delivering Hetch Hetchy Drinking Water

The seismically-resistant backbone of the Hetch Hetchy Regional Water System comes into service the week of the 25th Anniversary of Loma Prieta Earthquake

Recently, the San Francisco Public Utilities Commission (SFPUC) joined with Dave Pine, President of the San Mateo County Board of Supervisors, to celebrate the completion of the first tunnel under San Francisco Bay at the location where the first Hetch Hetchy Water through the tunnel enters Crystal Springs Reservoir. Eighty years ago this month, a similar celebration occurred in this exact spot when Hetch Hetchy water was first delivered to the San Mateo-Peninsula region through Bay Division Pipeline 1. That original lifeline, and the entire Hetch Hetchy System, was built in response to the 1906 earthquake and the devastating fires that ensued in its aftermath. 

History repeats itself. The multi-billion dollar Water System Improvement Program (WSIP) is a response to the 1989 Loma Prieta Earthquake and the likely seismic event that will occur in the Bay Area in the next 30 years. As one of the last WSIP projects, the Bay Tunnel replaces two aging pipelines (Bay Division 1 & 2) that sit on the Bay floor. The new Bay Tunnel acts as a seismically-reliable lifeline connecting our Hetch Hetchy and East Bay water supplies with customers on the Peninsula and in San Francisco. 

“Protecting our water supply also protects our entire regional economy,” said San Francisco Mayor Ed Lee. “The new Bay Tunnel is part of San Francisco’s multi-decade effort to upgrade the seismic reliability of our Hetch Hetchy Regional Water System and strengthen our water and sewer infrastructure to prepare for the next big earthquake.” 

While the occasion is historic, equally praiseworthy is the engineering prowess demonstrated by the hard working women and men that designed and built the Bay Tunnel. Construction on the Bay Tunnel began in April 2010, and the tunnel was just put into service after weeks of testing and disinfection. At $288 million, the project was delivered on-time and below the original budget estimate of $313 million.

“Ratepayers are investing in critical infrastructure upgrades to ensure that precious Hetch Hetchy Water will continue to be delivered after a major seismic event,” said Nicole Sandkulla, CEO of the Bay Area Water Supply and Conservation Agency. “The decision to invest 100 percent of rate payer money now, rather than later, will prepare us for the future major seismic event that we know will occur in our region.”

The Bay Tunnel is one of the last projects in the SFPUC’s WSIP – one of the largest water infrastructure improvement programs in the country. Like water utilities in many parts of the country and world, the SFPUC is in a race against time to buttress its aging infrastructure. Since 2002, the nearly $4.8 billion WSIP has strengthened the water lifelines that cross over the major earthquake faults in the Bay Area to deliver high-quality Hetch Hetchy Water to our customers. Comprised of 83 projects, WSIP is more than 80 percent complete and has seismically strengthened vulnerable pipelines and reservoirs, constructed redundant facilities and completed major projects like this one as well as the seismic slip-joint upgrade project at the Hayward Fault. 

WSIP was also an important economic engine helping to sustain our Bay Area economy after the 2008 Recession. Since 2002, WSIP investments have created 11,000 jobs, generated nearly 7,000,000 craft hours for workers and have trained new workforces in skilled trades, all while stimulating our local economy. 

“The new Bay Tunnel will ensure that we have reliable access to Hetch Hetchy water at all times, particularly within twenty-four hours of a major earthquake,” said SFPUC General Manager Harlan L. Kelly, Jr.  “The Water System Improvement Program has been an ambitious and successful undertaking.  We are nearing completion of the program, with just a few construction projects remaining such as the Calaveras Dam rebuild, which will replace the original dam built in 1925.” 

The 1989 Loma Prieta earthquake was a wake-up call for the Bay Area, serving as the catalyst for WSIP, the Bay Tunnel and many other infrastructure projects. The timing could not be more prescient. The US Geologic Service predicts a major earthquake will occur within the next 30 years in the Bay Area.