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Abstract Actions to reduce flood risk often appear to run counter to other societal goals, and resolving these conflicts is important as flood adaptations increasingly transform settlements and societies. Here, we evaluate the tensions between flood risk reduction and other priorities in the context of voluntary buyouts of flood-prone properties in the United States—a controversial flood response to restore land to open space, but with trade-offs. We apply a nation-wide systematic review (133 literature references, 1983–2023) to assess goals stated for buyouts and combine it with a comprehensive media analysis (281 media articles, 1993–2023) to compare those goals to the experiences and results perceived by buyout implementers, residents, and other practitioner groups. Across the systematic-review literature, flood risk reduction dominates goals expressed for buyouts (62.6% of documented goals), and local government predominates in this goal setting (61.7% of documented goals). However, involved and affected actors—especially residents—perceive outcomes beyond flood risk reduction, most notably in the experiences of buyout implementation itself (35.5% of documented resident perceptions) and in results impacting social and economic priorities (49.5%). Despite the difficulties of buyouts, the systematic-review literature largely reflects positive perceived outcomes (79.4% of outcome sentiments, weighing each buyout location equally), but nonprofit organizations and residents perceive largely negative outcomes. Media coverage related to buyouts is more negative than positive but with improved sentiments through time. Our findings point to the importance of designing, implementing, and evaluating flood adaptations not just as flood control measures given their consequences for other societal objectives. The uneven documentation on buyouts also implies opportunities to learn from contexts where buyouts have been integrated into everyday life with little fanfare, through mechanisms either novel or perhaps routine, yielding insights into making ambitious climate adaptations a common, more ordinary, and increasingly imperative occurrence. 

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. 

Inundation of coastal stormwater networks by tides is widespread due to sea-level rise (SLR). The water quality risks posed by tidal water rising up through stormwater infrastructure (pipes and catch basins), out onto roadways, and back out to receiving water bodies are poorly understood but may be substantial given that stormwater networks are a known source of fecal contamination. In this study, we (1) documented temporal variation in concentrations of Enterococcus spp. (ENT), the fecal indicator bacteria standard for marine waters, in a coastal waterway over a two-month period and more intensively during two perigean spring tide periods, (2) measured ENT concentrations in roadway floodwaters during tidal floods, and (3) explained variation in ENT concentrations as a function of tidal inundation, antecedent rainfall, and stormwater infrastructure using a pipe network inundation model and robust linear mixed effect models. We find that ENT concentrations in the receiving water body vary as a function of tidal stage and antecedent rainfall, but also site-specific characteristics of the stormwater network that drains to the waterbody. Tidal variables significantly explain measured ENT variance in the waterway, however, runoff drove higher ENT concentrations in the receiving waterway. Samples of floodwaters on roadways during both perigean spring tide events were limited, but all samples exceed thresholds for safe public use of recreational water. These results indicate that inundation of stormwater networks by tides could pose public health hazards in receiving water bodies and on roadways, which will likely be exacerbated in the future due to continued SLR. 

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.