Sidewalks are sinking in San Francisco’s Mission Bay neighborhood
San Francisco has a history of building sinking, and while the five-year saga of the Millennium Tower sliding into the mud of the bay may finally come to an end, sidewalk submersion in another neighborhood is now a cause for concern among residents.
There are larger gaps between the sidewalks and the buildings of many blocks in Mission Bay from year to year.
Last year, dramatic new photos of the sidewalk on 4th Street south of Mission Creek exposed the issue that sparked concerns about earthquake safety and the daily hazard to pedestrians.
The buildings themselves are safe because they’re built in bedrock and built earthquake-proof, but the streets and sidewalks aren’t, and are separating from the buildings at a rate of about a quarter of an inch a year, reports KPIX.
According to an expert, the ground in San Francisco’s Mission Bay is sinking faster than originally predicted and is getting worse with the paving. https://t.co/YfqIzaITj6
– KPIX 5 (@KPIXtv) November 24, 2020
The neighborhood on the east side of San Francisco where Mission Creek meets the bay has historically been an industrial area, but has undergone extensive development in recent years with the construction of the Chase Center and UCSF Mission Bay campus.
The area was established in a liquefaction zone on a landfill of an old freight yard and is still the largest drain in the bay for water from San Francisco’s underground streams. Soil in liquefaction zones behaves like a liquid under extreme loads such as an earthquake.
The sinking sidewalk problem creates a puzzling problem as any surface fixings are only there to add weight to the sidewalk and speed up its descent into the landfill.
Jennifer Smith Dolin, vice president of operations at Mercy Housing, a nonprofit nonprofit that promotes affordable housing in the neighborhood, told KPIX that the nonprofit cannot afford to pay for repairs in the long term.
“The solution and the amount we have available will probably not work out. If we can find a longer term solution, we need to raise funds to help, ”she said.
City records obtained from KPIX show that repair requests have increased in recent years – last year the city identified 59 locations in need of repair in the neighborhood, compared to about 10 calls per year 10 years ago. Most were not resolved.
