Understanding how sea level rise will affect San Mateo County residents, businesses, and the community services and infrastructure we all rely on is the first and most crucial step in building prepared, healthy and safe communities. The San Mateo County Sea Level Rise Vulnerability Assessment aims to do just that.
Assessment Goals
Map Assets and Future Risk Scenarios
Assess Vulnerability
Provide Actionable Results
Build Awareness
Facilitate Collaboration
Places at Risk
Places at Risk
Our networked infrastructure, which contains roads and highways, electric substations, and wastewater treatment plants that are essential to day-to-day community and economic functions and complex grid of services mean that sea level rise could affect us all. For example, a flooded highway, wastewater treatment plant or electrical substation could temporarily shut-down businesses, close roads and lead to many community wide disruptions. By working together, we can protect our community’s many assets, including neighborhoods, businesses, parks and beaches – places we all love.
Explore this section to better understand the risks across the entire Bayshore and the Coastside from Daly City through Half Moon Bay (not including south of Half Moon Bay) from a 1% annual chance storm plus 3.3 feet of additional sea level rise.
Legend
![]() | Future Erosion* |
![]() | Mid Level Scenario** |
![]() | Electric Substation |
![]() | Wastewater Treatment Plant |
![]() | Beach |
* Erosion impacts are estimated with 4.6 feet of sea level rise, but modeling does not consider shoreline armoring
** Estimated impacts are based on 1% annual chance storm or 1 in 100 chance of a storm occurring in any given year, plus additional 3.3 feet of sea level rise.
Sectors
Read more about how sea level rise could affect our different sectors and networked infrastructure in the County. Estimated impacts are based on a 1% annual chance storm, plus additional 3.3 feet of sea level rise (mid-level scenario).
27% of electric substations, 32% of transmission towers, and 67% of power plants could be exposed to flooding leading to community-wide disruption.
6% of rail stations (BART and Caltrain stations), 20% of County highways (Highway 101, State Route 92, State Route 1) and local roadways, and the SFO and San Carlos airports and Port of Redwood City could be at risk from flood damage.
Read more about the potential impacts and solutions for Transportation infrastructure and facilities in San Mateo County:
66% of parks, 85% of wetlands, and all our beaches could be lost to temporary or permanent flooding.
Read more about the potential impacts and solutions for Recreational and Natural places in San Mateo County:
80% of existing levees, berms, and other shoreline features could be exposed.
Read more about the potential impacts and solutions for Flood Protection Infrastructure in San Mateo County:
54% of wastewater pump stations and 63% of wastewater treatment plants could be exposed.
Read more about the potential impacts and solutions for Wastewater Systems in San Mateo County:
22% of storm drains, 63% of stormwater pump stations, and 49% of outfalls could be exposed to flooding.
13% of schools, 13% of emergency health care facilities, 12% emergency shelter sites, and 18% of police stations could be exposed to flooding.
Read more about the potential impacts and solutions for Community Services and Critical Facilities in San Mateo County:
13% of closed landfills and solid waste facilities could be exposed to flooding.
Read more about the potential impacts and solutions for Closed Landfills and Solid Waste Facilities /in San Mateo County:
People at Risk
People at Risk
Our built environment, which offers housing, transportation, and community services, and the biodiversity of our natural and recreational spaces, wetlands, beaches and forests contribute richly to our quality of life. They enhance our physical and mental wellbeing, and are a central part of what makes San Mateo County such a wonderful place to live, work, and learn. Our community needs to work together to ensure that we continue to be mentally and physically healthy.
We support mental health and prevent social and economic disruption by protecting our homes, infrastructure, businesses and community services. These enable us to work, access support systems, and meaningfully engage with our neighbors and communities. Avoiding disruption and displacement also reduces risks of stress, depression, suicide, and chronic illness.
We promote physical health and wellness by ensuring access to medical services and recreational areas, and by staving off post-flood related health hazards. Planning ahead can limit instances of trauma, drowning, carbon monoxide poisoning, mold-induced respiratory problems, water-borne diseases, and food-borne illnesses caused by food contamination and spoiled perishables.
Acting now will protect the livelihoods, health and wellness of over 100,000 people. We can make a difference by handling problems before they get worse, especially for those who have limited resources to prepare and recover including our children, elderly, lower income residents, and those who face unstable housing conditions and with limited access to vehicles. Taking action now is essential to the quality of life our entire community and in the best interest of our future generations.
What’s Being Done
Potential Strategies
Now is the time to prepare for sea level rise. San Mateo County is working collaboratively with our cities and key stakeholders to protect our communities, services, and infrastructure from sea level rise impacts. Developing and implementing a preparedness plan for San Mateo County requires careful evaluation of multiple potential actions, and then coordinated efforts to put our plans into action.
Actions are generally needed at building or site specific, neighborhood, city and regional scales across three areas (1) emergency preparedness efforts, (2) shoreline and site-specific strategies, and (3) policies, plans and procedure updates to address sea level rise.
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Mid to Long Term |
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Projects Underway
Navigate through the map to see projects and plans underway in San Mateo County to protect our communities and the environment.
What You Can Do
What You Can Do
While we adapt to changes, we must also work together to meet the challenge where it starts by working together to reduce greenhouse gas emissions and engaging in planning efforts. It’s time to get involved. Here’s how.
![]() | Everyone
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![]() | Residents
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![]() | Non-profits and Businesses
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![]() | County and City Government/Special Districts
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![]() | Elected Officials
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Our Plan
Next Steps
2018 | Phase I: Continue to Assess Vulnerability
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2019 | Phase II: Develop Adaptation Plan Framework and Strategy
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2020 | Phase III: Implementation and Monitoring
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Learn More

Appendices (350 MB)
