The Port of San Francisco (which runs 7.5 miles of the city’s waterfront, including the three miles reinforced by the seawall) had assumed that the wall was in need of improvement, but was unsure of how much until 2016, when the authorities issued a preliminary study seismic vulnerabilities. Unlike some dikes, those in San Francisco provide structural support as well as flood protection. The following Report 2020 detailed its weak points on both fronts. As climate change raises ocean levels, the seawall will increasingly have to operate in a context for which it was not designed. Since an earthquake can strike any day, the immediate priority of the port is ensure the integrity of the dike in such an event. But to do this, we must also take into account the rise in sea level and its uncertainties as to its speed and height. Risk mitigation decisions made now must take into account the unknowable.
Patrick King, who heads port and maritime works at Jacobs, the engineering firm managing the port resilience program, articulates the urgent challenge of designing a future waterfront. “This infrastructure was built for a certain environment that does not exist. ‘doesn’t exist anymore and is changing rapidly,’ he said. And now, to the best of their ability, “We have to predict what this environment will look like. “
“Wall” is a generous word for the pile of rocks sitting on the mud along the northeastern San Francisco waterfront. During the feverish early days of the Gold Rush, the San Franciscans built the sea wall in a botched effort to establish level ground at the edge of the hilly town. Horses struggled to carry wagons filled with gold up the hills, and the San Franciscans needed warehouses and counting houses on level ground. Eager for steam shovels to arrive from across the country, residents began to jump into the marshes of Yerba Buena Creek whatever was on hand: loose sand, city construction debris, junk goods, garbage, the remains of abandoned ships. After a year, San Francisco had grown three blocks into the bay.
To curb the construction chaos, the California legislature created a council of state ports commissioners to create a development plan for the port. Construction of their first breakwater – essentially a mission to rescue the destroyed port – began in 1867. A better-funded effort took off in 1878, and construction continued in stages over the next four decades.
While longevity hasn’t been at the forefront of the business, the wall is still standing, long exceeding what anyone might have expected. And for some experts, it is worrying.
“I would say San Francisco has a triple threat,” King said: earthquakes, rising sea levels and aging infrastructure.
So far, the wall has mostly worked, but barely. In the 1906 earthquake, the sea wall moved across the bay, crumpling streetcar tracks, breaking pipes and destroying homes. Entire sections of the street slid sideways; other portions have dropped a few feet. In today’s city, a similar disaster would be even worse.