By Thomas K. Pendergast

Someday another earthquake of the magnitude that hit San Francisco in 1906 is expected to strike again. A bond proposal to expand an emergency water system for fighting fires that will likely follow a massive quake was passed by the San Francisco Board of Supervisors. 

The San Francisco Public Utilities Commission (SFPUC) will put a $628.5 million bond measure before the voters in a special election to be held on March 3, 2020. It would fund seismic upgrades for police and fire stations, with $140 million of that money slated to expand the Emergency Firefighting Water System (EFWS), formerly known as the Auxiliary Water Supply System (AWSS), and put a new pump station at Lake Merced to feed it should that water be needed.

“This bond will deliver $140 million in crucial investments for protecting the west side of the city in the event of future disasters, including earthquakes and fires, and will allow us to expand the Emergency Firefighting Water System in the Sunset District and the Richmond,” District 4 Supervisor Gordon Mar told the board. “It is not a question of ‘if’ the next big earthquake is coming but when, and I’m proud to sponsor this important step for insuring that the Sunset and other westside neighborhoods are prepared to respond to emergencies.”

Mar also mentioned that the SFPUC has committed to add another $55 million to the project. 

“Our action today will protect the lives and property of westside residents and secure our future generations from disaster,” he said. 

The SF Budget Analyst’s Office estimates that if the bond passes, a single-family residence with an assessed value of $500,000 would pay an average additional property tax of $73.18 per year to cover the debt, and landlords can pass 50 percent of the tax on to tenants. The bond needs at least two-thirds majority of the vote to pass.    

The EFWS is a more robust pipeline network designed to withstand strong earthquakes and supply water at high-pressure to fight the conflagrations that might occur after a 7.8 earthquake, which is roughly the estimated strength of the 1906 temblor.

About 3,000 people died then, many of them possibly incinerated while trapped in rubble because of 300 broken water mains and 23,000 breaks on service connections in the City’s water supply, eliminating the water pressure needed to fight the ensuing conflagration.

In response to this disaster, the City built the AWSS, an independent high-pressure water system of pipelines and seawater pumps designed to withstand a massive earthquake and deliver enough water pressure to fight many large fires at once.

When it was finished in 1913, most of the City’s residents lived on the east side, so the original system was only built out, with some later expansions, as far west as 12th Avenue in the Richmond District and eventually 19th Avenue in the Sunset District. 

In the decades that followed, City neighborhoods expanded both westward and southward but the AWSS system did not follow, leaving about 15 neighborhoods in the western and southern areas vulnerable to the next firestorm.

After responsibility for the AWSS was transferred from the SF Fire Department to the SFPUC by former SF Mayor Gavin Newsom in 2010 to address a citywide budget deficit, the SFPUC did explore the idea of fully expanding the AWSS to completely cover the western and southern areas of the City, but balked at its estimated $600 million cost.

Voters have passed two bonds already, one in 2010 for $412.3 million and another in 2014 for $400 million, to modernize the city’s water distribution system, but a great deal of that money went to refurbishing and strengthening the transmission pipelines coming from the Hetch Hetchy Reservoir, which cross three major earthquake faults and run alongside the San Andreas Fault. 

Exploring AWSS expansion revealed that the current water sources for the system were not enough to supply adequate water pressure for an expanded system to cover the entire City. So, last year the SFPUC proposed constructing a “co-benefits” pipeline to carry water from the Sunset Reservoir and connect to both the domestic water pipelines and proposed high-pressure earthquake-resistant pipelines for use to fight fires after a disaster. This plan depends on a series of automated, mechanized valves to cut the pipelines off from domestic water pipelines, which will likely be broken and, like in 1906, be unable to deliver an adequate supply for firefighting.

An expert on emergency water systems, Professor Charles Scawthorn, of UC Berkeley, who was hired for consulting services by the SFPUC, said  that if the Sunset Reservoir holds (which has been re-enforced for earthquakes on the northern basin but not the southern basin) then it should have an adequate supply. If it does not, then a redundant supply from a pump station at Lake Merced and a seawater pump drawing from Ocean Beach would make the system more reliable. He also explained that the AWSS system now in place was designed with multiple sources and multiple layers to back-up the main water tanks and reservoirs.

Although there is already a pump station at Lake Merced, John Scarpulla of the SFPUC said it is not designed for the water pressure required by the EFWS, so they need to build another one, which will be funded by the bond. This will need to handle 30,000 gallons per minute of high-pressure water. He said the estimate for how much the new pump station at Lake Merced will cost to build is about $40 million. 

Not included in the bond, however, is funding for a seawater pump drawing from Ocean Beach. 

“We still plan to study it; we have not completed that study yet,” Scarpulla said. “None of the bond funding is earmarked at this time, to my knowledge, for completing the study but there are other funding sources to complete that study and we do plan to complete that study.” 

The water from Lake Merced is non-potable, but Scarpulla said they will design the pump station to deal with that, because the co-benefits line will be connected to the potable drinking water system. 

He explained that there will be two inlets to the pump station but only one outlet. The first inlet will bring potable water from a Hetch Hetchy-supplied water main, while the second would be coming directly from Lake Merced. 

“We will be designing our system to ensure that they meet all California standards for cross-contamination,” Scarpulla said. “If there is a situation where we do need to use Lake Merced water, the first thing that would happen is all of the valves to the domestic water system would be closed so that there would be no cross-connections.

“After the Lake Merced water was used the system can be completely flushed. It’s a pretty normal routine thing for us. Then it would be tested.” 

The original estimate of more than $600 million just to expand the AWSS system included the City’s southern neighborhoods like Crocker Amazon, Excelsior, Ingleside, Little Hollywood, Mission Terrace, Oceanview, Outer Mission and Sunnyside. This bond, however, will not provide funding to expand the system into those neighborhoods, which Scarpulla said is why the new price tag for the EFWS expansion is so much lower at $140 million.

“The SFPUC has also pledged $45 million on top of that,” Scarpulla said. “The SFPUC said yes to $45 million already and in the future they’re looking to add another $10 million to make it $55 million.”

The final price for the project has not yet been determined.