Bay Area prepares for sea level rise

ByTimothy Didion KGO logo
Tuesday, September 24, 2019
Bay Area prepares for sea level rise
If the battle against climate change has a front line, the shore of San Francisco Bay might be it.

SAN FRANCISCO (KGO) -- If the battle against climate change has a front line, the shore of San Francisco Bay might be it. At the County Parks Marina in Alviso, trucks rolled in like an armored column, delivering tons of dirt that will eventually be used to build a 4-mile-long sea wall.

"And the shoreline levee will follow this pond, which is dried out," says Rechelle Blank, an engineering supervisor with Valley Water.

Blank gave ABC7 a look at the project area from a raised platform in the Marina, a perch roughly 15 feet above the marsh and salt ponds that cap the southern tip of the Bay. It's approximately the same height as the planned levee.

"Which will be FEMA-certified to protect the community from coastal flood advances, as well as by 2067 rising seas," says Blank.

The project is just part of a climate change push that virtually circles the Bay. Both the Oakland and San Francisco airports are confronting projected threats from sea-level rise, while flooding in the North Bay has sparked proposals to possibly raise Highway 37.

On the southern waterfront of San Francisco, crews are hard at work on one of the most complex sea-level rise projects in recent memory -- raising the historic industrial complex at Pier 70 by 5 to 10 feet to ensure the buildings and surrounding shoreline area remain high and dry, as it's converted into a mixed use development.

"So along our shoreline, it's very diverse," says Elaine Forbes, executive director of the Port of San Francisco, which is in a public-private partnership on the Pier 70 project.

The work may eventually pale in scale to potential upgrades under consideration for the city's century-old seawall, which protects areas including downtown San Francisco. Forbes says the $425 million sea wall bond recently approved by voters could be just the beginning of what's needed.

"It's really a down payment for the larger project, which is going to cost us about $5 billion to take our whole Embarcadero sea wall stretch, three miles long, and improve it for seismic stability and for sea level rise. And we're also looking at the entire stretch of the San Francisco waterfront with the Army Corps of Engineers," says Forbes.

While holding rising tides back is necessary in some areas, David Lewis of Save the Bay says in others, it makes more sense to give the water a place to go by breaking down levees and restoring natural wetlands, which has been down other parts of the bay, including former salt ponds once operated by the Cargill Corporation.

"And what we've learned over the last decade is when you do that, the land recovers and returns to marsh very quickly," says Lewis.

Back in Alviso, engineers have already integrated wetland restoration into the final levee plan, with the goal of turning drying salt ponds into lush tidal marsh.

"We're hoping to reestablish that whole pond to look like Marina does today. And restore that lost tidal marsh," says Blank.

See more stories and videos about Building a Better Bay Area here.