by Thomas K. Pendergast
A new plan to expand the emergency water system for firefighting after a major
earthquake seems to be gaining support among San Francisco city officials,
but questions remain about options yet to be explored.
After the 1906 earthquake and subsequent fire – which killed an estimated 3,000 people,
many of them probably incinerated because of 300 broken water mains and 23,000 \
breaks on service connections in the domestic water supply which shut off water for the
ensuing conflagration – the City built the Auxiliary Water Supply System (AWSS),
a separate high-pressure water system composed of pipelines and pumps designed to
withstand a major temblor.
At the time, most of the City was on the east side of the peninsula, so the original system
was only built out as far west as 12th Avenue in the Richmond District, and eventually it
was built out to 19th Avenue in the Sunset District.
In the decades that followed, the City expanded westward but the AWSS system did not
follow, leaving about 15 neighborhoods vulnerable to a devastating firestorm, including
the Outer Richmond and Sunset districts, along with Bayview Heights, Crocker Amazon,
Excelsior, Ingleside, Little Hollywood, Mission Terrace, Outer Mission, Sea Cliff,
Stonestown and Sunnyside neighborhoods.
After responsibility for the AWSS was transferred from the SF Fire Department to the
SF Public Utilities Commission (SFPUC) by Mayor Gavin Newsom in 2010 to address a
citywide budget deficit, the commission came up with a “flexible hose” system consisting
of 12” hoses being dumped from flatbed trucks and manned by Neighborhood
Emergency Response Team (NERT) volunteers, a plan which the fire department
eventually deemed unworkable.
The commission 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
In January, the SFPUC announced its latest proposal, consisting of 12 “options” for
expanding the emergency water system to the west side, and to complement
the 30 new water cisterns that have been installed throughout the western and
southern parts of the City.
Of those, seven options propose a limited expansion of the AWSS using its current
supply sources of water tanks located at Twin Peaks, Jones Street and Ashbury
Heights. Experts, however, determined that a full expansion of the AWSS based
on only those sources would not supply the gravity-fed system with enough water
at high pressure to be reliable in the western avenues, so another source, the
Sunset Reservoir, was proposed to provide a supply of fire-fighting water.
Should the fresh water supply run out for any reason, the AWSS system already
has two seawater pump stations available to use the Pacific Ocean as a source, but
both of those are located on the east side of the city, and thus are limited in the water
pressure they can supply for the western and southern neighborhoods.
The remaining options now proposed include a “co-benefits” pipeline that uses
a main transmission line that carries fresh water from the Sunset Reservoir, which
can be used to supplement the City’s lower-pressure domestic water supply, and
stronger, more earthquake-resistant pipes. This plan depends on a series of automated,
mechanized valves working flawlessly to cut the pipeline off from the domestic water
supply immediately after a major earthquake because regular water pipes will likely be
broken and unable to deliver an adequate supply for firefighting.
A pump station at Lake Merced is also under consideration as a second source of
water for the co-benefits plan.
Conspicuously absent from any options, however, is an expanded AWSS system of
pipelines coming from the Sunset Reservoir, but without the “co-benefits” pipeline
involved at all. Such and AWSS line would not depend on the motorized valves serving
the potable “co-benefits” water pipeline, and thus would be completely independent of
the domestic water supply, but would boost the water pressure for firefighting on the
Also missing are any plans for a seawater pump on the west side drawing water from the
With an estimated cost of $109 million, the favored plan, Option 12, is more expensive
than the other 11 options, yet much cheaper than constructing a fully expanded
At a Board of Supervisors’ Government Audit and Oversight Committee meeting on
Feb. 7, District 1 Supervisor Sandra Lee Fewer outlined the issue during a hearing about
the new options.
“In the Richmond District there are thousands of homes, wooden and built very close
together, that would be vulnerable to a fire in the case of a major earthquake or other
disaster,” Fewer said.
“Between the Richmond and the Sunset, we’re talking about 42,000 structures that
are not currently covered by a high-pressure emergency water system.”
District 4 Supervisor Katy Tang said she supports the SFPUC’s Option 12, with its co-
benefit potable pipeline, regardless of the expense.
“I’m really happy with what I see here in terms of Option 12 being the best option,”
Tang said. “Yes, it is the most expensive one but we have heard from the community that
they don’t care about costs, they care about safety.”
London Breed, president of the Board of Supervisors, mentioned the importance
of getting it right this time.
“As we move forward, the kinds of decisions that we make will impact our
neighborhoods for generations to come so we have to do the right thing now and focus
on quality, especially when we talk about infrastructure,” Breed said.
Professor Charles Scawthorn of UC Berkeley is an expert on emergency water
systems. He was brought into the planning process last year as a consultant to
the SFPUC to help formulate the new plan. Fewer asked him if hooking up just
the Sunset Reservoir would give the Richmond District an adequate water supply
after an earthquake. Scawthorn said the answer was a matter of both quantity and
reliability. If the Sunset Reservoir survives the earthquake without bursting, then, in his
opinion it would provide enough water supply for the Richmond.
But, reliability is a different matter because the reservoir is only a single source of water
for the west side. He referred to how the original AWSS system was designed.
“They built in multiple sources of supply in multiple layers,” Scawthorn said.
“Ideally, you would want to have multiple sources of supply in the western part of
the city. Therefore, beyond the Sunset Reservoir, in the long run, a second source of
supply, whether from Lake Merced or from the Pacific Ocean, is highly desirable. As San
Francisco is built out you want to have sources of supply at all four quadrants
of the City.”
Fewer asked him if a pump at Lake Merced was good enough to ensure an adequate
supply or if a seawater pump on the west side would be better.
“Ultimately, I would like to see, and I’m not paying for it, but I would like to see both
sources,” Scawthorn responded.
During the public comments period of the meeting Eileen Boken read a letter to
the committee that she said was written by Nancy Wuerfel, who couldn’t be there
that day. In the letter, Wuerfel suggested there was another reason the potable water
pipe of Option 12 was actually being pushed.
“I believe that they support Option 12 because water rate funds could be used to
offset the cost,” Boken said. “I do not agree that the city’s water rate should be
the underwriter of the city’s AWSS construction or maintenance.”