UC Berkeley researching Peninsula's sinking shoreline

A new research report from a University of California Berkeley geophysicist is raising alarms about the fate of patches of Bay front land built on fill.

It shows the ground is sinking, which is made worse by rising sea levels. Researchers say the problem of sinking started as soon as progress dictated portions of the bay front in Foster City, Union City, Treasure Island, and SFO were filled in for development.

“We knew this was happening but we didn’t really have observations showing where the sinking is happening and how fast,” said UC Berkeley geophysicist Roland Burgmann from his office via a Skype interview.

Burgmann says he’s spent the better part of a decade using satellite images and hands-on measurements to map the problem. In blue, local land subsidence, or sinking, is at a rate of the thickness of nickel annually. Yellow shows projected incursions from Sea Level Rise at a tenth of an inch per year. Combine the two, and by the end of this century, It’s a red alert for large areas inundated with water.

“By 2100, large areas in these places will be flooded. And we’re only looking at average sea levels,” said Burgmann.

Many residents living at or close to the Bay say they’ve known fill areas were gradually sinking. But they’re alarmed to learn adding in rising sea levels could put their properties underwater – with a few generations..

“I don’t see any infrastructure to support a move away from that. I think there would be a lot of chaos to respond to that,” said Kelly Kelso. Pat Doolittle said, “We need to be thinking a lot about solutions. We can’t just keep doing things the way we’ve been doing them.”

Doctor Burgmann has been talking to the U.S. Geological Survey and city leaders about incorporating this new data into future urban planning. In the short-term, he suggests building sea walls, levees or berms and marsh lands to help preserve existing communities..

“This is something that affects all of us. So if Fremont sinks first, ok but eventually this will catch up to everybody around the world,” said Kelso.

And to that point, Doctor Burgmann says our problem is shared with coast cities built on fill around the country and world – from Florida to New Orleans to The Big Apple. They too will have to decide how to save areas that are both sinking and seeing rising sea levels.