Priorities

San Mateo County is already experiencing the water-related impacts of climate change, including extreme storms, drought, coastal erosion, and flooding. Studies by other agencies and universities show that sea level rise threatens more people and property here than in any other county in California. Accordingly, OneShoreline was established by State legislation in 2019 as the first independent government agency in California to work across jurisdictional boundaries to plan for, and build regional resilience to, climate change. OneShoreline is currently focused on four priorities:

 

Plan land use, private development, and public infrastructure for future climate conditions in coordination with regional resilience projects

Regional resilience rests on jurisdictions evaluating and approving new developments and infrastructure projects with future—rather than historical—climate conditions in mind. OneShoreline's Planning Policy Guidance (2023) contains template text for general plans and zoning ordinances, as well as information on development agreements and project reviews, to help jurisdictions ensure that private and public assets can function for their intended lifespans and contribute to community resilience without the need for costly retrofits later. In 2026, we are developing a new guidance focused on future-conditions planning for key public infrastructure assets (stormwater and wastewater/water recycling systems, roads, parks, marinas, and utilities).

 

Advance projects that align long-term resilience for developed, natural, and recreational areas across jurisdictions; and economic resilience for property owners and renters

OneShoreline is advancing a number of projects on the Bayside of San Mateo County to build long-term resilience in our region,  including the Millbrae and Burlingame Shoreline Resilience Project, San Bruno Creek Resilience Project, and two projects in the Colma Creek Flood Zone. We are also developing shoreline resilience plans for Brisbane as well as five southern Bayside cities (East Palo Alto, Menlo Park, Redwood City, San Carlos, and Belmont) to help these cities meet State requirements for shoreline adaptation planning. 

On the Pacific Coastside, OneShoreline is supporting a project to build resilience for a flood-prone wastewater treatment plant serving Half Moon Bay and nearby unincorporated communities. In addition, a rapidly growing climate change impact in much of the nation, including San Mateo County, is the increasing cost and decreasing availability of home insurance products. OneShoreline is working with the nonprofit Insurance for Good to develop pilot programs to address insurance challenges. 

 

Provide early warning of, and reduce the impact of, today’s extreme storms made worse by rising tides

OneShoreline continues to operate, maintain, and expand the countywide Flood Early Warning System—an integrated network of stream, precipitation, and tide gauges for monitoring flood risk in real time. This system serves as an alert system and collects data for developing flood protection solutions. The flood monitoring webpage is accessible to both emergency responders and the general public. Improvements and expansion of the Flood Early Warning System are an ongoing effort.

 

Develop ongoing funding streams to build our collective resilience

The above three priorities reflect the need to address some of the most pressing challenges associated with climate change in our county. As this need is only going to grow, we are obliged to secure stable funding to continue this work and leverage outside project financing. 

 

 

 

 

Accomplishments to date

Completed construction of the Bayfront Canal and Atherton Channel Flood Protection and Ecosystem Restoration Project

This project protects five mobile home parks and other housing and businesses near Bayfront Canal and Atherton Channel from frequent and damaging flooding. Local agencies began planning this project in 2009, with OneShoreline assuming the role of lead agency in January 2020. Over the next 15 months, OneShoreline completed environmental review documents and secured permits, funding, and land access. Construction of this $9.5 million project began in May 2021 and was completed in 2022—on schedule and within budget. By diverting flows from Bayfront Canal to ponds managed by the U.S. Fish and Wildlife Service during major storm events, the new underground culvert system has demonstrated its ability to reduce flood risks in vulnerable areas along the Bay.

Hired staff and establish independent financial systems, policies, and procedures for a new government agency

A well-run government agency requires supportive and collaborative elected leadership and dedicated, competent staff.  Within OneShoreline’s first six months of operation, the Board of Directors hired its first CEO, who in turn hired project and finance staff who established financial independence and new financial systems for long-term efficiency and growth. Evidence of sound financial stewardship is the fact that OneShoreline has been able to extend the three years of start-up funding from all jurisdictions in the county to nine years of operations, and it has provided millions of dollars to local projects to reduce flooding and enhance the environment.

Advanced multi-jurisdictional projects to align long-term resilience for developed, natural, and recreational areas across jurisdictions

OneShoreline focuses on projects that have long-term meaningful objectives and achievable outcomes for multiple jurisdictions where there is local support and where OneShoreline has a clear role that adds value. Objectives for our work include protecting against extreme storms and a substantially higher sea level, restoring marshes and other natural features for their flood protection and environmental benefits, and incorporating trails for their recreational and connectivity benefits.

Over the past several years, OneShoreline has made substantial progress on the Millbrae and Burlingame Shoreline Resilience Project, which aims to (1) protect Millbrae and Burlingame from coastal and inland flooding and (2) improve shoreline trails and ecosystems. The Draft Environmental Impact Report (EIR) is planned for release in Fall 2026. OneShoreline has also advanced projects along San Bruno Creek and Colma Creek, and we have secured funding for shoreline resilience planning in Brisbane and five southern Bayside cities (East Palo Alto, Menlo Park, Redwood City, San Carlos, and Belmont) to meet State requirements.  

Expanded and maintained Flood Early Warning System

OneShoreline's countywide Flood Early Warning System is an integrated network of stream, precipitation, and tide gauges for monitoring flood risk in real time. This system serves as an alert system and collects data for developing stormwater management solutions. The flood monitoring webpage is accessible to both emergency responders and the general public. Four dashboards have been created for Atherton Channel, Belmont Creek, San Bruno Creek, and Colma Creek to provide watershed-specific information. System expansion was completed through installation of new monitoring stations at flood-prone locations, and we continue to maintain the system to ensure reliable operations.   

Secured multi-year permits for debris removal from flood-prone Bayside creeks

Major storms caused significant flooding along several Bayside creeks in San Mateo County in December 2022 and January 2023, mainly due to sediment and vegetation buildup reducing water flow capacity. In June 2023, OneShoreline led the process to secure 5-year permits to enable us and other jurisdictions to remove debris in the most flood-prone locations of four creeks. In Fall 2025, OneShoreline secured the required permits to complete targeted sediment removal at locations on San Bruno Creek, Cordilleras Creek, and Atherton Channel. In October 2025, OneShoreline completed debris removal on San Bruno Creek under these permits. Other jurisdictions can perform debris removal on the other creeks beginning in June 2026. 

Developed Planning Policy Guidance 

In June 2023, OneShoreline’s Board adopted a first-of-its-kind Planning Policy Guidance to help jurisdictions plan land use and private development for future climate conditions and in coordination with regional resilience projects. As of early 2025, five cities have incorporated aspects of the Guidance, and several other cities are slated to do so as part of the updates to their General Plan Safety Element.