(BCN) — Marin County could see its entire shoreline flooded during an extreme storm before the end of the century unless coordinated measures are taken to address sea level rise in the Bay Area.

As part of a state-mandated effort to create a shoreline resiliency plan, the county Board of Supervisors got a glimpse Tuesday of what the consequences of inaction could be if efforts are not made to protect the shoreline from rising sea levels.

The board received a report from the San Francisco Bay Conservation and Development Commission, known as BCDC, a regional state regulatory body that has created a regional strategy dubbed “Bay Adapt” to coordinate the mitigation efforts.

Two websites were introduced at the meeting that can keep the public informed about the planning process, bayadapt.org and adaptingtorisingtides.org.

Sea levels along the United States coastline are projected to rise by between 10-12 inches by 2050, matching the amount of sea level rise from 1920-2020, and rise by as much as 2 feet by 2100, according to the National Oceanic and Atmospheric Administration.

Flooding in Marin County could impact 28,000 residents, 104,000 existing jobs, and 85,000 planned jobs, according to projections from the commission.

Additionally, 13,000 existing housing units and 70,000 planned units could be compromised or destroyed during a significant storm in the next 40 to 100 years.

“So, it doesn’t matter if you don’t personally live near the shoreline, this is an issue that will impact everyone in the Bay,” said Dana Brechwald, assistant planning director for climate adaptation at BCDC.

Rail and highway transportation could also be impacted, with significant flooding forecast for state Highway 37.

Novato, Mill Valley, Corte Madera and San Rafel will experience some of the earliest flooding in the Bay Area if sea levels rise by 12 inches. During a significant storm, water levels could surge by as much 96 inches by the year 2100, which would completely flood Novato.

The projections are fueling a proposal to invest about $110 billion in shoreline resiliency around the Bay Area. The cost of inaction could cost double that amount, according to Brechwald. Marin County’s costs are estimated to be $17 billion, second-highest in the region behind only Alameda County.

California Gov. Gavin Newsom signed Senate Bill 272 into law earlier this month. The law, authored by state Sen. John Laird, D-Santa Cruz, requires coastal governments to create a sea rise or shoreline resiliency plan in order to receive funding from the state to implement the plan.
The plan will be created by the county with guidance from BCDC and must be approved by the commission by 2034.

The commission is trying to coordinate governments in the Bay Area because affecting the shoreline in one place impacts the entire Bay, Brechwald said.

A virtual community meeting is planned for Thursday from 1-4 p.m. to get feedback on the plan, which includes several potential projects around the county, including resiliency work on Highway 37, restoration of multiple marshes and wetlands, and additional climate assessments. Register at bayadapt.org by clicking on the participate tab and registration link.

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