ASSESSING FLOOD RISK FOR STATE OF CALIFORNIA PROPERTIES

This study assessed flood risk to state-owned properties throughout California, including critical infrastructure (hospitals, armories, chemical storage), congregate housing, government buildings, and public service sites. Previous work, including our own, has assessed flood hazard to the general population; here we focus on the nature and magnitude of flood exposure specific to government facilities, using California as a broad case study. We analyzed state-owned properties’ hazard exposure, utilizing: 1) The Federal Emergency Management Agency (FEMA)’s designated Special Flood Hazard Area (SFHA, known as the 100-year-floodplain, or the area mapped with a 1% annual chance of flooding); 2) dam inundation maps; and 3) a commercial flood-risk model (Fathom Global) that estimates climate-influenced flood risk for 2020 and 2050. We found that 1,787 California state-owned structures (comprising over 7.35 million square feet of interior space) are located in FEMA’s SFHA. Flood exposure is spread broadly across the State of California agencies, with the highest proportions of at-risk facility space operated by District Agricultural Associations (DAA), the Department of Rehabilitation and Corrections (DCR), and the Department of Housing and Community Development (HCD). These results impact strategies for disaster planning, management, and mitigation in several ways: 1) DAA sites often serve as evacuation assembly points and disaster response areas; (2) DCR facilities house large incarcerated populations in group quarters, which are difficult to relocate; and 3) HCD facilities house many of California’s migrant farmworkers. Over half of DCR’s properties are considered high priorities as designated by the American Society of Civil Engineers (ASCE), indicating a disproportionate exposure to vulnerable populations. These facilities should be considered as high priorities for mitigation investment. Our recommendations for managing this class of state-owned flood exposure include improved planning and oversight of new facilities, mitigation of existing sites, and new forward-looking policies such as community-based insurance. State-owned properties could “anchor” new insurance initiatives, significantly leveraging, motivating, and providing economies of scale to flood-prone communities across California.