SFO to San Mateo Bayside flood barrier plan sparking worry

A natural barrier like a retention pond would work better, according to Schneider, who also believed the proposal could limit Bay access and has not received adequate community input.

“I’m one of those people that believe that we’re going to be at sea-level rise much greater than what America wants to deal with, but we still have time to do the job and do it correctly. OneShoreline should go back to the drawing board, they should hold public meetings,” she said.

OneShoreline, the county’s Flood and Sea Level Rise Resiliency District, is overseeing the project. It is currently in the proposal stages and is awaiting an environmental impact report, permitting and feedback from various government entities before construction would begin, CEO Len Materman said.

If approved, the structure would connect from the San Francisco International Airport’s barrier, which is in the construction phase, and span from Millbrae as far south as Coyote Point on the San Mateo and Burlingame border, Materman said during an Oct. 16 Burlingame City Council meeting.

Multiple studies point to the county’s unique vulnerability from sea-level rise over the years, which is projected to rise up to a foot in the next 30 years and up to 6 feet over the next century. It will significantly affect the 53 miles of county shoreline, threatening cities on the Peninsula with low-lying areas home to vital infrastructure and private developments.

Schneider said that Millbrae Bayfront area — which she acknowledged as comparably smaller than other city Bayfronts included in the project — has already been “taken” from the city by San Mateo County and San Francisco, particularly because of SFO, and building a barrier would leave the city with minimal remaining Bay.

Materman said that building offshore, as opposed to other potential options like building floodwalls around creeks, would create the least impact on public access.

“The barrier is open 99% of the time, but closed when big atmospheric rivers and king tides come,” he said. “The offshore structure doesn’t have to be this big, imposing wall.”

Schneider also contends Millbrae was not adequately included in the planning process for the barrier, with only one representative on the OneShoreline board for the entire Burlingame to Brisbane region, and would have liked to see requests for public input. Materman said Millbrae’s input had been included from the beginning of the project.

Schneider, who received her degree in environmental science, said that she also sees climate resiliency as a major issue for Millbrae residents, but that nature-based solutions are the answer.

“Instead of the old Army Corps of Engineering thing, which is ‘build a levee, build a wall, build a dam,’ let’s see how nature can help us resolve some of these environmental problems,” she said.

She proposed retention ponds, which capture water and gradually absorb it into the ground, as one potential solution, and enhancing wetlands so they can fully function as another.

But for OneShoreline, another important objective of the project — and one that might require a barrier — is reducing or removing flood insurance requirements for both Millbrae and other Peninsula residents.

“That’s an important goal, and one that requires structural elements,” Materman said, explaining that the Federal Emergency Management Agency doesn’t certify natural barriers when considering if flood insurance is a requirement for homeowners.

The size of the tidal lagoon and project costs are yet to be determined. Materman hopes construction will be done within the decade.