SFO’s seawall is crumbling, needs $1.5 million to stop failure

San Francisco lawmakers will vote tomorrow on whether or not to declare an emergency at San Francisco International Airport, where a crucial seawall has been crumbling since the summer, raising the specter of runway flooding.

In a September letter to SFO Commissioner Larry Mazzola, airport director Ivar Satero cited “unforeseeable and unexpected” damage to a runway seawall designed to shield low-lying airport zones against high tides.

Anton_Ivanov / Shutterstock.com

Anton_Ivanov / Shutterstock.com

Geologists spotted “seepage problems” and a “potential sinkhole” at the end of two runways back in July.

So far there ois no indication of what exactly is causing the damage, which Satero characterizes as erosion gradually eating away at the wall.

But he warned that without repairs “the seawall may fail and flooding is likely,” in an “imminent threat” to airport operations.

In fact, Satero wanted repairs done before November 30, and the airport declared the seawall problem a state of emergency in September and skipped the bidding process for contractors.

But the city has not yet approved the $1.5 million necessary to fix up the hole in the dike. Two-thirds of the cost go toward riprap: deposits of big, irregular stones poured into vulnerable areas to provide a bulwark against erosion.

San Francisco has already seen a notably wet and rainy autumn, with more storms forecast for this week.

With an eye toward the future, the airport is also angling for a massive shoreline project that will guard against monster “100-year storms.” Which, as the name suggests, happen roughly once every century, and for which we’re a bit overdue, statistically speaking.

The projected cost for that: $60 million.

• September letter [SFO]
• Emergency Declaration [Board of Supevisors]
• Riprap [State of Massachusetts]
• SFO Shoreline Protection [Bay Area Water Management Plan]
• City Preps For Constant Flooding [Curbed SF]