One Shoreline outlines multimodal plan to protect Millbrae and Burlingame shoreline from sea-level rise

One Shoreline, the countywide flood-and-sea-level-rise resiliency district, gave Millbrae City Council an update March 24 on a three-mile shoreline project that would extend from the airport's planned seawall at Highline Canal through Millbrae's Bayfront Park into Burlingame.

The presentation, delivered by Chief Executive Len Matterman and Project Director Summer Bundy, described existing conditions that leave the shoreline vulnerable to higher tides and storm surge: shoreline elevations as low as 8 feet NAVD, tidally connected creeks that back up into city storm systems, and fragmented, nonengineered protections in front of hotels and commercial properties. The agency said the corridor includes critical infrastructure and transportation corridors at risk and estimated “over $2 billion of infrastructure” and roughly $370 million of buildings exposed under future sea-level scenarios.

The draft project concepts reviewed by the council include a three-tier siting approach: where possible place protection onshore tied to redevelopment parcels; in constrained locations build nearshore levees or seawalls; and in intermediate locations use a hybrid approach that combines onshore elements and limited bay encroachment. Specific proposed features include raising sections of Bayfront Park, levees with ecological riprap to create intertidal habitat, groins to trap sediment, replacement tide gates on key creeks, and a continuous, widened (18-foot) Bay Trail with overlooks and low-tide access.

One Shoreline staff said they are preparing a public draft environmental impact report targeted for late summer (the administrative draft is currently under city review) and emphasized that design, permitting and construction would be phased. The agency noted it has used an $8 million Coastal Conservancy grant (about $4 million for agency operations and $4 million toward this project) and two federal grants that fund early work, but said it lacks a stable, long-term countywide funding source for widespread construction and maintenance. Staff called for collaborative phasing and a financing plan with the cities and property owners.

In public comment, resident Ann Schneider pressed One Shoreline and councilmembers to ensure mitigation money tied to San Francisco International Airport (SFO) projects that affects Millbrae is spent locally rather than redirected elsewhere. One Shoreline responded that Bayfront Park (SFO-owned) is included in their EIR analysis and that agency staff are in ongoing discussions with SFO about construction logistics, land rights and implementation roles; who ultimately constructs and maintains individual components remains to be negotiated.

Councilmembers asked about responsibility for pre- and post-project damages, SFO coordination, and project cost estimates. One Shoreline reiterated that responsibility and long-term maintenance arrangements are unresolved in the implementation-planning phase, that much of the corridor is in Burlingame (which provides redevelopment opportunities to leverage funding), and that definitive construction estimates will be developed during design and phasing. The agency said no comprehensive construction cost estimate was available at the presentation stage.

Next steps: One Shoreline plans to publish a public draft EIR in the late summer, continue targeted stakeholder and regulatory outreach and work with Millbrae and Burlingame on phasing and finance options. Councilmembers and One Shoreline agreed to continue technical and subcommittee-level discussions ahead of the public release.