Mapping under uncertainity : spatial politics, urban development, and the future of coastal flood risk

Abstract

Flooding is the most common and single largest source of disaster-caused property damage in the United States. The past year, 2017, was the costliest for weather and climate disasters in US history. To mitigate these losses, the Federal Emergency Management Agency and National Flood Insurance Program produce Flood Insurance Rate Maps (FIRMs) that often provide the most comprehensive and authoritative flood hazard information for a community. Despite reform efforts for greater map accuracy, spatial politics may render the computationally efficient 100- year floodplain delineation of questionable effectiveness, equity, and legitimacy for long-term land use planning. Given changing coastal flooding and sea level rise, how can risk mapping inform and improve future urban development? The dissertation: (1) positions flood mapping in the larger context of urban risk computation; (2) chronicles and statistically analyzes the nationwide map adoption process; (3) uses spatial analysis, document review, semi-structured interviews, and grounded theory to identify how these updates are proxies for nonstationary flood risk in Plymouth County, MA and New York City, NY; (4) compiles a novel survey of recent large-scale development decisionmaking in Boston, and (5) pilots a probabilistic indicator that models project-level flood risk information. I observe that the differences in location, wealth, and race between counties are associated with varying FIRM adoption process durations as well as whether a county may appeal and receive revised maps. I argue that coastal communities with sociopolitical clout can bend the process of computational risk assessment, through either contestation or collaboration over risk classification. I find the planning information shock of updated maps, however, is a largely insufficient signal to change developer behavior. Therefore, I pioneer the Future Flood Resilience Indicator (FFRI) as a decision support tool for developers to understand the long-term flood risk of their proposed development projects and planners to ascertain the impact of their policies. In conclusion, the dissertation provides policy makers with: (1) new data on how map adoption is not a purely scientific and technical process, (2) further evidence that the current 100- year flood standard is inadequate, and (3) resilience-building tools for land use planning.