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Abstract Avoiding floodplain development is critical for limiting flood damage, yet there is little empirical evidence of how local governments effectively avoid floodplain development. We conduct a mixed-methods study to explain how local floodplain management influences floodplain development in New Jersey, a state with high development pressure and flood risk. We find that 85% of towns developed relatively little in the floodplain from 2001 to 2019, and they achieved this with commonplace land use management tools and modest levels of local government capacity. One hundred twenty-six New Jersey towns put none of their new housing in the floodplain 2001–2019. Our findings run counter to common reports of rampant floodplain development requiring legal innovation and capacity-building campaigns and suggest alternative approaches for promoting floodplain avoidance. We find multiple paths to floodplain avoidance, weak support for previously identified drivers, and strong evidence that the keys to avoidance include having a few high-quality tools that are well-implemented, requiring consistency, coordination, and commitment of local officials. The multiple paths and importance of maximum, rather than average, quality might explain the mixed evidence in prior research connecting floodplain management actions and development outcomes. A lack of attention to towns that limit floodplain development impedes our ability to learn from and disseminate their successes. Contrary to our expectations, we show that floodplain avoidance can be and is achieved through routine municipal practices. Our findings underscore the importance of sustained commitment to development management as a core tool for limiting flood risk. 

Abstract Moving away from hazardous areas may be an important adaptive response under intensifying climate change, but to date such movement has been controversial and conducted with limited government or private-sector support. Research has emphasized resident perspectives on mobility, but understanding how professionals view it may open new avenues to shape future outcomes. Based on 76 interviews with professionals involved in climate responses in South Florida, we evaluate perceptions of adaptation goals, the potential role of climate mobilities in pathways supporting those goals, and associated constraints and enablers. The practitioners interviewed anticipate multiple types of climate mobilities will occur in the region, at increasing scales. Interviewees perceive climate mobilities at present, especially migration and gentrification where climate plays some role, as causing distributional inequities and financial and sociocultural disruptions, and they view existing adaptive strategies as best serving those who already have adequate resources, despite practitioners’ personal commitments to social justice goals. Although many practitioners feel prepared for their own, limited roles related to climate mobilities, they judge the region as a whole as being unprepared to support the retreat they see as inevitable, with a need for a more ambitious long-term transition plan. Achieving this need will be difficult, as practitioners indicate that climate mobilities remain hard to talk about politically. Nevertheless, interviewees believe some households are already considering moving in response to climate risks. Discussions of climate mobilities, through interviews and far beyond, may encourage more mindful choices about and engagement in climate-driven transformations. 

Historical adaptation pathways (HAP) analyses identify sequences of multi-causal factors that shape climate change adaptation actions. Such analyses can be valuable for understanding why systems respond differently to climate risks, assessing important adaptation drivers and constraints, and identifying potential path dependencies. This paper synthesizes existing (and still emerging) HAP methods in order to present a more standardized and generalized approach to studying historic adaptations. The proposed method combines inductive and deductive approaches and draws on established practices from grounded theory to increase validity, including process tracing, memoing, construct definition, and member checking. This approach is designed to provide historical and contextual information that can be incorporated into a decision model or be shared with stakeholders and community members. In addition, future comparative studies based on this replicable approach could allow for theorization as to the casual mechanisms that engender successful adaptation. The approach is illustrated using a coastal adaptation case study in South Carolina, USA, with one of the main insights being that the island would not exist in its current form without the actions taken by concerned citizens, whose efforts ultimately helped combat the erosion caused (in part) by local jetties. Several areas for methodological improvement and theoretical development are also noted, as the aim of this work is both to enable cross-study comparisons of future HAP research – which can inform adaptation practice – and to provide a method that can be improved upon in future iterations. 

Development patterns and climate change are contributing to increasing flood risk across the United States. Limiting development in floodplains mitigates risk by reducing the assets and population exposed to flooding. Here, we develop two indexes measuring floodplain development for 18,548 communities across the continental United States. We combine land use, impervious surface, and housing data with regulatory flood maps to determine what proportion of new development has taken place in the floodplain. Nationwide from 2001 to 2019, 2.1 million acres of floodplain land were developed, and 844,000 residential properties were built in the floodplain. However, contrary to conventional perceptions of rampant floodplain development, just 26% of communities nationwide have developed in floodplains more than would be expected given the hazard they face. The indexes and the analyses they enable can help guide targeted interventions to improve flood risk management, to explore underlying drivers of flood exposure, and to inform how local‐to‐federal policy choices can be leveraged to limit hazardous development. 

Flood damage has severe and long-term repercussions for households and communities, and continued housing development in floodplains escalates damages over time. Policies and interventions to reduce damage depend on assumptions about housing stock and residents, but assessments of flood exposure to date largely focus on community-scale characteristics at a single point in time, masking potential within-community differences and their evolution through time. We measure residential development in the floodplain nationwide over time to characterize the type and value of U.S. floodplain housing stock and to assess how new development contributes to flood exposure. Over 4M U.S. residences built from 1700 to 2019 (4.8% of all residences built during that time) are located within current regulatory floodplains. These residences are concentrated at the affordable and expensive extremes of the housing value spectrum, reflecting deep differences in the social vulnerability of floodplain residents. Floodplain housing stock often differs substantially from the local market, with coastal floodplains containing relatively expensive housing and inland floodplains containing relatively affordable housing. New housing development has not occurred equally across these contexts. In the past two decades, more floodplain development has occurred in communities with relatively expensive floodplain housing, and mobile home construction in floodplains has slowed. The bifurcated patterns in floodplain housing, across values and geographies, demonstrate the importance of considering the specific population at risk and how it may differ from the broader community when tailoring flood risk management approaches.