Sea Level Rise Vulnerability Assessment

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

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Assess Vulnerability

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Provide Actionable Results

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Build Awareness

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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.

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orange color blockFuture Erosion*
light teal color blockMid Level Scenario**
electric substation iconElectric Substation
wastewater treatment plant iconWastewater Treatment Plant
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* 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.

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.

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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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Near Term
  • Assess risks to critical buildings and sites
  • Elevate or adapt structures for continued operation
  • Develop emergency response plans, flood monitoring and alert systems
  • Adopt new development standards and ordinances for at risk areas
  • Update building design standards and codes d to incorporate flood risk best practices
  • Work with neighboring cities to develop a menu of strategies to protect our infrastructure and people from future flooding and sea level rise risks
Mid to Long Term
  • Build new buildings above flood levels and use flood-proof materials and practices
  • Reduce flooding through nature-based solutions, including vegetated, permeable, and tree-covered surfaces, water detention systems and habitat restoration
  • Relocate assets inland and convert vulnerable land uses
  • Implement large scale wetland or regional shoreline protection projects

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.

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  • Attend future Sea Change SMC events like ‘Shrinking Shores’ or ‘King Tides’. Visit our Get Involved page for more information
  • Share information about sea level rise preparedness with your neighbors
  • Participate in your city’s community emergency response team. To sign up visit:
  • Organize as a neighborhood to prepare for storm emergencies
  • Visit your city website to learn about and participate in planning and adaptation efforts in your community
  • Take public transit or ride a bike at least once a week
  • Opt up to 100% renewable electricity with Peninsula Clean Energy’s Eco100
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Non-profits and Businesses
  • Evaluate and prepare for risks for your business by conducting a vulnerability assessment and developing a preparedness strategy
  • Develop a Climate Action Strategy to reduce greenhouse gas emissions emitted through your business operations
  • Offer incentives to employees to take transit or bike to work
  • Join the Sea Change SMC efforts to learn more about adaptation strategies and support local efforts to protect your businesses
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County and City Government/Special Districts
  • Integrate adaptation strategies into policies, plans, building codes and operations
  • Complete local vulnerability assessments and develop plans to adapt key facilities and protect the shoreline
  • Work with other jurisdictions to identify and prioritize city-scale and regional shoreline protection measures
  • Develop targeted neighborhood plans to build safe and stronger communities
  • Develop a targeted public outreach campaign to increase awareness of climate change impacts and sea level rise
  • Locate businesses and homes close to transit
  • Invest in public transit and improve network of bike lanes and pedestrian safety
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Elected Officials
  • Be a champion for sea level rise and allocate resources for staff to undertake efforts to plan and prepare for sea level rise and flooding impacts
  • Be an advocate for vulnerable populations and prioritize efforts such as energy efficiency and building retrofits, and flood preparedness resources for those with less capacity to respond to sea level rise

Our Plan

Next Steps


Phase I: Continue to Assess Vulnerability
  • Complete risk and impact assessment for the South Coast and unincorporated areas of San Mateo County
  • Evaluate vulnerability of key County facilities, including health facilities and parks, and countywide infrastructure, such wastewater treatment plans and pump stations
  • Support partners with evaluating sea level rise risks and impacts at the city level and by sector
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Phase II: Develop Adaptation Plan Framework and Strategy
  • Establish guidelines to help cities address sea level rise in existing plans, policies and operations
  • Identify priority areas for sea level rise adaptation and develop a strategic action plan
  • Develop a menu of adaptation strategies to initiate planning efforts in identified priority areas
  • Establish outreach and educational program to engage youth and County residents
  • Create sea level rise policy guidance and framework for cities and County to adopt
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Phase III: Implementation and Monitoring
  • Update plans and policies to address and plan for sea level rise
  • Select adaptation strategies and develop project concepts for flood, erosion, and sea level rise preparedness
  • Conduct a cost and benefit analysis on a range of project concepts to conceptualize economic and development feasibility
  • Develop a menu of Funding Strategies to pay for planning, building and maintenance of future projects
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