Hazards on the Embarcadero

The “multi-hazard risk assessment” for the northern waterfront prepared for the Port of San Francisco goes into extensive detail on what could occur along the Embarcadero without seismic upgrades and an adaptive approach to sea level rise. Among the study’s findings:

1 A major earthquake “will cause significant settlement and lateral spreading” along the seawall, the study found. The filled soil on the inland side of the seawall could abruptly plunge as much as a foot, causing severe damage to adjacent buildings and underground utilities and Muni transit lines.

1 Public agencies see ferry service as essential to evacuate people after a major earthquake. But first, people have to reach the water — and crossing a ravaged Embarcadero could be “the weak link in an earthquake,” the report warns. “Without access, otherwise functioning maritime assets and operations cannot function.”

1 An earthquake on the scale of the 1906 temblor would cause such extensive damage to the Embarcadero’s historic finger piers and bulkhead buildings that “reconstruction or repair might not be appropriate or feasible.”

1 Without significant proactive action, the study estimates the port could suffer $1.5 billion in damages related to earthquakes by 2100. The long-term impact of rising tides could be much more costly — “between $4.5 billion and $29 billion,” by 2100, depending on the pace of change.

1 If sea levels rise 2.2 feet and there’s an extremely high tide, city pipes could sustain longlasting damage: “significant floodwater (could) enter through catch basins and manholes ... the increased salinity in the wastewater system may impact treatment plant operations and increase corrosion rates of wastewater infrastructure.”

1 “Underground transit systems, like BART and much of Muni’s light rail, are highly vulnerable to flooding,” the report warns. More than 1 foot of sea level rise could inundate the Market Street subway, shutting down transit access far beyond the Embarcadero. “The cascading effects of severe and frequent mobility disruption, particularly to transbay trips, may ... threaten regional economic activity.” The full report will be available at www.sfportresilience.com.