San Mateo County's Sea Level Rise Vulnerability Assessment: An Overview and What's Next

Climate change impacts are already being felt across the globe, and the case for planned approaches to climate change adaptation is clear. Sea level rise is one of the primary and most devastating impacts from climate change, and it is of critical importance in the San Francisco Bay Area, particularly for San Mateo County, which is bounded by the Pacific Ocean to the west and the San Francisco Bay to the east. The County is highly vulnerable to the effects of rising sea levels. If left unmanaged, future flooding and coastal erosion could pose considerable risks to life, safety, critical infrastructure, the County’s natural and recreational assets, and the economy. The assessed value of parcels in the project area exposed to near-term (present-day) flooding exceeds $1 billion, and the assessed value of parcels exposed to erosion and flooding in the long term (50-100 years) totals roughly $39.1 billion. More than 30,000 residential parcels and 3,000 commercial parcels may also be vulnerable in the long term. Vulnerable assets are located along both the Pacific Coast and the San Francisco Bay; they include critical infrastructure (police stations, hospitals, wastewater treatment plants, and schools); essential regional transportation networks and infrastructure (Bay Area Rapid Transit [BART], Caltrain, Highway 101, State Route 1); and important regional natural and recreational assets (Pacifica State Beach, the California Coastal Trail, and the Ravenswood Pond Complex). In spring of 2018, the County of San Mateo, through the Sea Change SMC Program, completed a Vulnerability Assessment to further understand the risks of sea level rise. A variety of social vulnerability factors were considered including language barriers, rent vs. owned housing, transportation cost burden, the elderly, young, etc. The report serves as the first step of the Sea Change SMC Initiative, whose purpose is to increase the resilience of the County’s economy, environment, and communities through collaborative planning and projects.