Community choices for building resilience and mitigating risks: Retreat versus retrofit

Hazard mitigation encompasses a wide range of strategies, including building protective structures, retrofitting existing buildings, regulating land use, and relocating from high-risk areas. Among these, relocation or retreat stands out as markedly different from the other mitigation measures. In this paper, we present a comparative analysis of retreat and retrofit as two distinct mitigation options, using a longitudinal dataset of mitigation projects funded by two federal programs, the Hazard Mitigation Grant Program (HMGP) and Flood Mitigation Assistance (FMA) between 2000 and 2019. We find that most communities receiving federal grants choose either buyouts (a form of retreat) or retrofits, with very few pursuing both. Our analysis explores the factors influencing a community's implementation of general mitigation, retreat or retrofit projects at the zip code level. We show that disaster damage generally increases HMGP-funded mitigation projects, with more severely affected localities performing more buyouts than retrofits. For both programs, we find that localities with less levee protection tend to implement more buyouts, and buyouts are more common in localities with lower housing prices, while more retrofits occur in higher-priced areas. Notably, our results indicate that communities with more Black or Hispanic populations undertake fewer projects under both programs, suggesting a potentially inequitable distribution of mitigation resources across U.S. communities.