San Mateo has launched a plan to protect its shoreline from sea-level rise and coastal flooding, with public comment now open on the first phase of the work.

The city's Subregional Shoreline Adaptation Plan, or SSAP, will map out how San Mateo defends homes, roads and infrastructure against rising water. The San Francisco Bay Conservation and Development Commission (BCDC) has issued an Initiation Notice recognizing the effort, according to the city's project page.

San Mateo is among the first agencies in the region to formally begin this process.

The plan is required under Senate Bill 272, signed into law Oct. 7, 2023, which directs all local governments along the Bay shoreline to complete adaptation plans by Jan. 1, 2034. BCDC adopted its Regional Shoreline Adaptation Plan on Dec. 5, 2024, setting the framework local agencies must follow.

The city secured a Caltrans Sustainable Transportation Planning Grant in 2024 to fund the work. The grant amount has not been disclosed.

The Bay shoreline accounts for one-third of California's coastline but is expected to bear two-thirds of the state's total economic damage from sea-level rise, according to BCDC's regional plan. A 2023 study cited in that plan estimated that defending the entire Bay shoreline from worst-case flooding by 2050 would cost at least $110 billion.

The project team has already completed an Existing Conditions report documenting current shoreline conditions, habitat and infrastructure that could be vulnerable. An interactive version is open for public comment on the city's Konveio platform.

The plan document itself will be organized into seven elements, from existing conditions to a final project list. The work began with existing-conditions research in September 2025.

A vulnerability assessment and adaptation strategies phase runs from May 2026 through April 2028.

The first public meeting on existing conditions and vulnerability is set for Tuesday, Oct. 6, from 6 to 7:30 p.m., at the Main Library's Oak Room. A second meeting on adaptation strategy is set for July 2027, and a draft plan presentation is planned for February 2028.

City Council review and approval is targeted for June 2028. If approved by regulatory agencies, the completed plan would position San Mateo to pursue funding for shoreline protection projects, according to the city's Strive San Mateo planning site.

Andrea Chow, the city's sustainability analyst, is the project contact and can be reached at [email protected] or (650) 522-7007.