Westside Seawater Pump Plan Extinguished

By Thomas K. Pendergast

A proposal to install a seawater pump for fighting fires on the City’s west side after a big earthquake was rejected by the San Francisco Public Utilities Commission (SFPUC), although they do support building one on the southeast side. 

A seawater pump on the west side would supplement plans already in the works to use water from the Sunset Reservoir and Lake Merced for an extension of the Emergency Firefighting Water System (EFWS), an auxiliary water system designed to withstand earthquakes similar in power to the one that struck San Francisco in 1906. 

San Francisco in flames after the 1906 earthquake. Much of the City was destroyed because of inadequate firefighting water supplies. Courtesy photo of a painting by W. A. Coulter.

John Scarpulla of the SFPUC told San Francisco supervisors at a recent Government Audit and Oversight Committee meeting that the commission used a scenario of a 7.9 magnitude earthquake on the San Andreas Fault line to model their post-earthquake firefighting needs projections. 

They concluded that approximately 240,000 gallons of water per minute will be required to fight fires citywide, and they will need that amount available for possibly 25 hours at a time without supply interruption. That comes out to 360 million gallons of water.

“We looked at all areas of the City; the east bayfront, the north bayfront, what we call the rocky area north and south on opposite sides of the Golden Gate Bridge, and then the southern dunes,” Scarpulla told the supervisors. “A seawater pump station is not immediately advised for the west side at this time by the city agencies and our consultants. We support additional redundancies for all areas of the EFWS; that’s important. 

“We believe the priority is for the build-out of the system to all neighborhoods for equitable fire protection first. And so that is why we don’t immediately advise for it at the west side at this time,” he said.    

A 2018-2019 Civil Grand Jury report titled “Act Now Before it is Too Late: Aggressively Expand and Enhance Our High-Pressure Emergency Firefighting Water System” raised questions about post-earthquake fire protection after the next major earthquake, and whether firefighters will have enough water pressure to fight the resulting conflagrations. If it happens sooner rather than later, neighborhoods in supervisorial districts 1, 4, 7, 8, 9 and 11 could be engulfed in a firestorm similar to the fire which destroyed much of the City in 1906. 

  A $628 million bond measure was passed in March 2020 to improve fire stations and emergency facilities across the City. More than $154 million of that is slated to expand the EFWS – formerly known as the Auxiliary Water Supply System (AWSS) – into the Richmond and Sunset districts. This system of earthquake-resistant pipelines would cover large swaths of those districts and place a new pump station at Lake Merced to provide extra water for the expanded system.  

The 1906 shaker killed thousands, many incinerated while trapped in rubble due to hundreds of broken water mains and thousands of broken service connections. The system failures eliminated the water pressure needed to fight the ensuing firestorm. In the years immediately following that devastation, the City built the AWSS, a separate high-pressure water system composed of pipelines and seawater pumps designed to withstand a massive earthquake and deliver enough water pressure to fight large fires.     

At the time, 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, however, as the City expanded westward, the AWSS did not follow, leaving more than a dozen neighborhoods in the western and southern areas vulnerable to another devastating firestorm.   

If, however, the demand for post-earthquake firefighting water in the Sunset District is too high or the southern basin of the Sunset Reservoir fails and there is not enough water pressure for the Richmond District, there is no money in the bond set aside for a saltwater pump near Ocean Beach in District 1 as a backup. Funding for that option would have to be provided later. 

Also not included in the 2020 bond is money to expand the high-pressure pipelines into the southernmost areas of the City, leaving the south end of districts 7, 8, 9 and 11 far more vulnerable to fire than anywhere else in San Francisco. 

 “The gallon-permitted need for the west side … is 37,000 gallons per minute out of the total 240,000 gallons per minute. The water sources that will be connected … meet this need. They cover this demand,” Scarpulla explained to the supervisors. “So, Lake Merced with its 1.7 billion gallons worth of water provides more than three weeks-worth of water to fight fires and meet this demand. In all of the modeling scenarios we ran, even the most extreme ones, even the ones where the worst fires were seen, there was not a single fire that lasted even close to three weeks on the west side ….

“Lake Merced is the most efficient and quickest way to provide a virtually unlimited water source, 1.7 billion gallons, to fight fires on the west side and we’re hooking that up first,” he said. “That’s key and the fire department was adamant that the first water source it would hook up to was Lake Merced.”

 The SFPUC estimates that installing a pump station to cover the whole 37,000 gallons per minute needed for the west side would cost $180 million in 2021 dollars.

 They do, however, recommend adding a seawater pump station to the southeast quadrant of the city, claiming it would be a lot easier and less costly to do so.

District 4 Supervisor Gordon Mar, however, responded that the lack of a seawater pump station on the west side still worried him. 

“I appreciate the current plan … to add a new one in southeast San Francisco, but I think for the west side, I share the great concern of the residents out here of the current plan to instead have water from Lake Merced and the Sunset Reservoir … great concerns about what that would mean to the environment of Lake Merced; that’s already been struggling with low water levels. And with the extreme drought that we’re facing, the water level that we’re facing has been a major problem that needs to be addressed.” 

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