What is sea level rise and what does it mean for San Mateo County?

Sea level rise is a result of our changing climate. Higher temperatures cause ocean waters to warm and expand, and land-based ice to melt. These two factors result in higher sea levels. San Mateo County is one of the most vulnerable counties in California to sea level rise. In 2009, the Pacific Institute estimated that San Mateo County has $24 billion in assets at risk, including 11 square miles of wetlands and 115,000 homes in low-lying areas. According to projections for California, sea levels could increase by up to 2 feet in the next 35 years, and by up to 5 1/2 feet by the end of the century.

Rising TidesTo address the challenge of sea level rise, the County has initiated SeaChange SMC. SeaChange SMC is led by the County’s Office of Sustainability and Supervisors Dave Pine and Don Horsley, in partnership with the California State Coastal Conservancy, U.S. Congresswoman Speier, and representatives from San Mateo County’s twenty cities. We are working closely with a technical working group, policy advisory committee, and a community task force.

Vulnerability Assessment: The first step in addressing sea level rise is to understand what is at risk. SeaChange SMC is working on a vulnerability assessment for the bay and coastal shorelines to identify key assets at risk from different scenarios of sea level rise and storm events. The assessment includes a focus on nature-based solutions and reducing impacts to underserved communities, and involves San Mateo County cities, businesses, and community groups.

Preparing for floodingData Challenges: One of our goals is to gather data and information on existing assets and flood control structures in a centralized Geographic Information System (GIS) using the County’s Open Data Portal. Although there is a lot of information already available, it is not comprehensive or it is scattered across different agencies and organizations online collaboration tools. Given that flood waters do not know jurisdictional boundaries, the challenge of climate change and rising tides is a regional issue. Collaboration between all the affected stakeholders is critical to implementing effective solutions.

First Community Workshop! On January 30, 2016, SeaChange SMC hosted a free Sea Level Rise Open House to discuss sea level rise, present updates on the assessment, and gather community feedback. Over 180 community members learned about sea level rise and the vulnerability assessment through presentations, displays, and hands-on activities. Members of our Community Task Force developed a “What Do You Value” station, where attendees listed things important to them that could be impacted by sea level rise. In addition, the Association of Bay Area Governments (ABAG) had an activity for attendees to share how they are prepared for flooding.


Stay Involved: There are many ways to stay involved: attend one of our community events, read our blog for regular updates, and join our SeaChange SMC Facebook Group to participate in the ongoing dialogue. This blog will be used to share more information about our Vulnerability Assessment, high tide events like King Tides, and any sea level rise related articles and photos.

Now is the time to prepare for this slow moving emergency.