In this study, we aimed to explore how coastal flood risk has changed across time and space, as well as the EJ implications linked to the (re) distribution of flood risk across six different New York City communities. Below, we discuss three key aspects of our study results and implications for policy and future work on flood risk: interactions between drivers, the uneven distribution of vulnerability, and the need for analytical frameworks and policies that address intersectional risk.
Interactions between drivers of flood risk
Based on the so-called “risk triangle”, our study relied on an understanding of risk as the interaction between hazard, exposure and vulnerability. We consider two key processes as the main drivers of coastal flood risk. First, the process of urban change (shifts in the built environment and demographics) drives changes in exposure and vulnerability. Second, the redrawing of the 100-year floodplain within FEMA’s NFIP affects the hazard component of the triangle by updating the magnitude of the event’s impact in terms of extent. It is important to consider that the socio-economic metrics used in this study were developed during the period that followed the 2008 financial crisis, making it a potential driver of change. However, while the socioeconomic consequences of the crash were most acute in its first two years, our study shows that social vulnerability increased during the period of recovery that followed (McMahon 2018). Future iterations of this may focus on answering the differential effect of the financial crisis inside and outside of the floodplains.
We find that together these processes continue to increase coastal flood risk in NYC. Here we discuss the major policies affecting ongoing floodplain development, namely, zoning, flood resilience planning, and the existing national flood insurance program (NFIP). These social drivers are closely intertwined with updates to the SFHA and its relationship with observations of sea level rise and increased frequency of extreme weather events.
Policies affecting ongoing floodplain development
Our analysis shows that coastal flood risk significantly increases due to ongoing development across the studied CDs within the effective floodplain. Population, assets and land use acreages continued to increase in the effective floodplain during the period studied, linking shifts in flood risk to exposure changes. In some of these communities, social vulnerability has increased in addition to development-borne exposure. For example, during the period studied, the Bloomberg administration boosted urban renewal within NYC’s waterfront with PlaNYC: A Greener, Greater New York (City of New York 2007). Many other subsequent plans, visions and regulations (NYC Planning 2011a, 2013; NYC City Planning Commission 2013; New York City 2019) have provided the city with a framework to carry out intensive waterfront development, especially in Manhattan and Brooklyn, increasing human and infrastructure exposure.
These plans are linked to changes in land use, built densities, and other aspects of urban form that are regulated through zoning. Zoning in NYC incorporates updated base elevation requirements for buildings based on the preliminary floodplain (Berry and BenDor 2015). However, these types of changes aim to ensure resilient development within the floodplain, without restricting it. As the “safe development paradox” states, there is a danger that a false sense of security can trigger development in areas where risk mitigation measures are only designed to handle events of a certain magnitude and scale (Burby 2006; Stevens et al. 2010). In contrast, the introduction of policy measures such as the Special Coastal Risk Districts and the Resilient Neighborhoods Initiative limited the density of new development in the rezoning of neighborhoods such as Broad Channel and Hamilton Beach in Queens. New residential development was limited to single-family detached homes only and community facilities with sleeping accommodations were prohibited (NYC Planning 2017a). In East shore, in Staten Island, this limitation was combined with the requirement to receive an authorization from the City Planning Commission for any new development and horizontal enlargement (NYC Planning 2017b).
However, not every recent rezoning in NYC has incorporated flood risk mitigation. In East Harlem, a 2017 rezoning project shows commitment to invest in the development of affordable housing in lots that might be highly exposed to flooding (Mayor’s Office of Operations 2019). Higher levels of limiting development on the floodplain would require total prohibition of new development. As Stevens et al. (2010) claim, the feared economic consequences of such a decision (e.g.loss of tax revenue, compensations to landowners and developers) should not mask the increasing economic losses caused by flood hazards when they hit communities like the ones studied here. However, current federal policy, embodied in the NFIP, subsidizes ongoing floodplain development. This contradiction emerges from FEMA’s mandate to safeguard coastal resilience while maintaining coastal property markets, which was key to secure property holders and regulators buy-in to pass the NFIP through Congress. Presently, rate-payers do not provide enough insurance capital to cover potential losses (Horn and Brown 2018), and are likely underestimating the outstanding liabilities due to future flooding (Shively 2017). Taxpayers subsidize the NFIP, thus public money is effectively used to cover private developers’ risks. At a more granular level, the flood insurance rates set by the FIRM fundamentally depend upon the representation of flood likelihoods and severity represented by the SFHA, which we address in the following section.
Changes in floodplain extent driving the production of flood risk
We find that the SFHA in the CDs studied grows in extent by 45.7% due to the preliminary redrawing. The CDs of Coney Island and the Rockaways show a dramatic increase in the impact that a 100-year event has on them. These results are based on the preliminary floodplain, which is subject to change in the coming years due to its revision. Additionally, in this study we limited the analysis to changes in the extent of the floodplain, future iterations should consider changes in the base flood elevation too as a way of incorporating gradients of risk. Nevertheless, these CDs were severely impacted by Superstorm Sandy, which flooded vast areas outside of their effective floodplain and had a return period of 103 years for its peak water level (Lopeman et al. 2015). Hence, we consider that, at least in the case of Coney Island and Rockaway, the preliminary floodplain does not likely overestimate risk. Other CDs experienced slight reductions in their floodplain extents, such as the 4% decrease in City Island/Co-op City (210). This seemingly small reduction excludes the 10,000-unit development of Co-op City from the SFHA, waiving the obligation to purchase flood insurance (FEMA 2011). The preliminary SFHA boundary remains 50 m from buildings within the development, raising important questions about how bounding flood exposure based on a single return period may inappropriately define risk (Ward et al. 2011; Koerth 2017; Kousky 2018). After decades of reliance on the 100-yr floodplain designation, the NFIP is expected to experience a deep transformation in October 2021 with the expected adoption of Risk Rating 2.0. This transformation aims to make it easier and fairer to assess flood risk at the property level by incorporating technological advances and updated understandings of flood risk (FEMA 2019). Still, the details of how risk will be assessed is unclear. Furthermore, changes in flood risk assessment methods may be limited if future risk due to climate change remains unassessed, limiting the consideration of non-stationary risks in current urban planning processes (Pralle 2019).
The change in hazard probability as represented by the SFHAs’ redrawing of the 100-year floodplain is just one framing of flood risk defined by a largely technical knowledge system process. The outcome of the decisions made at each step of this process reshape life on USA’s waterfronts by determining the enforcement of the NFIP, and are often sharply contested by local communities and developers (Pralle 2019). These contestations often center on the financial impacts of mandatory flood insurance on low income households, as well as the ability of developers to sell floodplain real estate. In NYC, the ongoing contestation of the SFHA leaves significant numbers of residents, which in our study represented a ~ 10% increase in the flood exposed population, uncertain as to whether they should purchase flood insurance. Due to this lack of a clear understanding of their risk, some homeowners have given up the policies they voluntarily purchased after their homes were damaged by Sandy (Choi et al. 2019).
While these social contestations are ongoing, climate change and sea level rise will likely continue to increase coastal flooding frequency and severity within the region (Sallenger et al. 2012; Orton et al. 2016). The NPCC’s (New York City Panel on Climate Change) projected 100-year floodplain for 2050 has a very similar area to the current 500-year floodplain, roughly corresponding to Superstorm Sandy’s highwater line. Thus, recent extreme weather events may be the new normal under climatic conditions anticipated by the NPCC, and as our discussion of the NFIP, zoning, and resilience planning emphasizes, current programs of flood response and waterfront development continue to exacerbate the underlying drivers of risk with uneven social consequences.
Uneven distributions of vulnerability to flood risk
Overall, we find that flood risk is distributed unevenly in the community districts studied. The current distribution of unevenly vulnerable communities across NYC is the result of complex histories of urban development on New York City’s coastline, where land was cheaper, and many of the city’s public housing projects were erected from the 1940s to the 1960s. A major reason why land was cheap was due to practices of redlining which deeply intertwined racist geographies of real estate investment (Aalbers 2014) with the delineation of the floodplain through the 1930s (Nelson et al. n.d.) Low prices of land in turn as well as access to infrastructure, facilitated the development of coastline industries and associated environmental contamination. Thus, race and class remain embedded within three major dimensions of EJ affecting the distribution of vulnerability to flood risk, namely the patterns of renting and home ownership, public housing, and the distribution of environmental hazards.
Housing markets, home ownership and locational benefits
NYC’s historical legacy of segregation has affected homeownership rates of people of color by denying access to mortgages and financial capital. Today, in boroughs like Queens and Brooklyn, low homeownership rates among people of color persist, as do higher rates of foreclosures and barriers to refinancing, reflected by higher rates of needed home repairs (Baker et al. 2018). These racial and income differences are rooted in historical zoning laws and redlining, policies creating decades of systematic under-investment in areas where largely immigrants and people of color lived, as well as flood zones. Various degrees of redlining happened in all the PEJAs we studied (Nelson et al. n.d.). Even when people of color own homes, they may face continued vulnerability due to structural inequities in labor markets and incomes. Combined with increasing prices of flood insurance premiums and prohibitively expensive flood-resilient retrofits, some homeowners of color are presently at higher risk of displacement from floodplain areas, further worsening the homeownership and racial wealth gaps that exist in the city (Paganini 2019). Additionally, redlining may have also led to higher levels of rentership among people of color by limiting intergenerational wealth transfer among discriminated groups (Jones 2017). Development and gentrification patterns, especially in the Lower East Side and East Harlem, complicate this picture as economic upscaling and neighborhood deterioration thrive side by side (Goldstein 2017). Historical and current factors depressing housing value and reducing housing access must therefore be considered alongside patterns of specifying zones of increased real estate values, often driven by perceived or real amenity value.
The amenity value of floodplains is derived from the perceived locational benefits driving coastal development, reflected in higher than average real estate values in floodplains that have other desirable attributes. For instance, sales inventories and recorded sales have dramatically increased in areas hit by Hurricane Sandy (Quintana 2017; Erdos 2018) also fueled by newly developed ferry routes. New high-end developments have increased home values in wealthy beachfront properties, as well as in lower income areas like Far Rockaway, triggering concerns over housing affordability and displacement.
An analysis of amenity value will be necessary to understand counter-intuitive patterns of social vulnerability within the CDs studied. In the case of City Island/Co-op City (210) and, to a lower degree, Rockaway (414), more affluent floodplain residents have lower socio-economic vulnerability than non-floodplain residents. Moreover, although the Bronx is the poorest in the nations’ 435 congressional districts (DiNapoli and Bleiwas 2018a), some of its coastal areas are also home to some affluent and middle-class communities, including Pelham Bay, City Island and Co-op City. These areas also count with a higher concentration of amenities such as shopping, recreational districts, and parks. This situation mirrors what Collins et al. (2018:319) observed in the case of Miami and Houston, in that there exist counterintuitive patterns in social exposure to flood risk driven by the “...indivisibility of amenity values from high risk landscapes”.
Recognizing the importance of amenity value also highlights the relationship between resilience planning and real estate value. For example, the North shore is Staten Island’s poorest neighborhood, where development was restricted in 2004 (NYC Planning 2004), and yet has recently seen large increases in property rents and value. In 2011, the City proposed several waterfront redevelopment projects as part of North Shore 2030 (NYC Planning 2011b). Such projects are designed to improve landscaping for stormwater reduction, bulkheads and shoreline, as well as abiding to building code limitations. However, these efforts could jeopardize housing affordability in the long run (DuPuis and Greenberg 2019) in an area where a third of the families face severe rent burden, devoting 50% of their income on rent (DiNapoli and Bleiwas 2018b).
Public housing
The share of public housing in each community district is also an important driver of vulnerability. We found higher vulnerability of populations exposed to the floodplain in Lower East Side, Stapleton and East Harlem, districts with high concentrations of public housing in the floodplain. For instance, Lower East Side has 26 public housing developments with more than 30,000 residents, nine owned by the NYC Housing Authority (NYCHA), exposing ~ 21,000 low income and predominantly people of color to the floodplain (NYU Furman Center 2019). The Lower East Side has similar racial and economic characteristics as Rockaway, and has also been characterized by a process of gentrification with decreasing home ownership and growing rents (NYU Furman Center 2018). Earlier events further demonstrate increased vulnerability of public housing residents as prior work found that six NYCHA owned public housing properties had no running water, heat, or repair work done on their houses long after Hurricane Sandy (Graham et al. 2016). Seven years after the hurricane, repair work funded by FEMA had only been completed in 2 of the 200 damaged NYCHA buildings (Aponte and Smith 2019). FEMA only agreed to finance repair work for flood related damage, leaving out critical renovations on long-standing leaks and mold issues across NYCHA developments (Kasakove and Williams 2019) that may have an effect on the overall resilience of its residents.
Environmental hazards
Besides public housing and homeownership, environmental pollution makes up a more complex understanding of vulnerability in coastal areas. The PEJAs in our study contain contaminated sites and toxic facilities, exposing the linkages between land use and zoning and the disproportionate environmental burdens in low-income or communities of color. For instance, in East Harlem, there are 25 records of Open Spills, 171 registrations of Petroleum Bulk Storage (PBS) and 96 sites where the presence of hazardous pollutants requires an environmental impact assessment (Planning 2016). Stapleton’s north shore hosts a Significant Maritime and Industrial Area (SMIA), including 5.2 mile2 declared as contaminated by the U.S. Environmental Protection Agency. All of the SMIA’s polluted sites are located within 70 ft from homes (Checker 2009). Might the defensive infrastructure fail during a flooding event, the impact of the flooding would escalate due to the combination of water with hazardous pollutants.
Although the NYC Mayor’s Special Initiative for Rebuilding and Resilience (SIRR) and the Hurricane Sandy Rebuilding Task Force did not adequately address the EJ consequences of SMIAs (Sandy Regional Assembly 2013), the 2019 Climate Leadership and Community Protection Act (CLCPA) contains several EJ provisions (Morris and Farmer 2019). The result of efforts by 180 environmental, community and labor organizations, the CLCPA includes a target for disadvantaged communities to receive 35% of the benefits from the state’s climate programs, the creation of a Climate Justice Working Group, a community Air Monitoring Program and a requirement for the state to prioritize projects that both reduce GHG emissions and eliminate criteria pollutants in historically disadvantaged communities.
EJ consequences are also tied to New York City’s infrastructure system in the floodplain. For instance, in West Rockaway sewage overflow from the Rockaway Wastewater Treatment Plant in Rockaway West and the two pumping stations in Rockaway East mixed with Hurricane Sandy flood waters and seeped into homes, creating a polluted mix that lingered for weeks (Rockaway West Planning Committee 2013). FEMA approved investments to repair the plant, but in 2018 it was still relying on generators for power. The cascading effects of power infrastructure failures are well known (Serre and Heinzlef 2018) and may exacerbate existing inequalities in the ability of people to pay for their home remediation if action is not taken at multiple-scales.
The social vulnerability patterns of flood risk in New York City’s floodplains are inextricably linked with long standing racialized geographies in waterfront communities. Existing patterns of home ownership and rentals, the distribution of public housing and environmental pollution in the floodplain will likely continue to be exacerbated by future storm events. Environmental governance and climate resilience programs by the state and local government need to embed explicit provisions addressing such disparities.
Towards analysis and policies addressing contextual flood risk
Our analysis indicates coastal flood vulnerability in NYC is highly uneven, with some vulnerable communities increasing in flood exposure, while other areas experiencing increasing development despite increasing flood risks. These results highlight complex interdependencies between the social processes of representing flood risks, the uneven consequences of being flooded, and the palette of responses available to manage flooding. Future work on coastal flooding should utilize a concept of risk that includes vulnerability, pays attention to the procedures shaping the distributions of flood risk and vulnerability, and guides more just processes for reducing flood risks.
Social, ecological, technological systems (SETS) frameworks clarify connections across social, environmental, and technical dimensions, including the relationships between representations of complex urban systems and the social processes that seek to transform them (McPhearson et al. 2016; Grabowski et al. 2017; Markolf et al. 2018). These urban systems conceptual framework focuses on interdependencies across social, ecological, and technological domains of cities and can help to emphasize urban transformation and processes of knowledge generation, allowing us to consider how the distribution of flood risk is inseparable from the flood knowledge system. Within such a framework, we can tie improved biophysical knowledge about current and future flood risks and technical processes for deciding on flood adaptation pathways, with a more nuanced understanding of social vulnerability. While our analysis has emphasized the potential uneven consequences of flood risks, our discussion emphasizes the social processes shaping outcome vulnerability, a form of ‘contextual vulnerability.’ Contextual vulnerability approaches emphasize that vulnerability is not just determined by sensitivity to outcomes of undesirable events, such as climate related coastal flooding, but is a product of the processes defining, managing, and producing vulnerability (O’Brien et al. 2007). A contextual lens reinforces the idea that the social and spatial distribution of flood risk cannot be separated from longer running EJ concerns over procedural equity, in particular within the institutional processes shaping how flood related infrastructure investments are prioritized. Presently, embedded inequalities in infrastructure decision-making may lead to more socially powerful actors receiving a disproportionate share of flood mitigation resources or benefitting from increasing property values. Within the CDs studied, this appears to be the case in Far Rockaway, where procedural inequity overlaps with distributional inequities in post-hurricane infrastructure efforts. For example, the $341 million boardwalk funded by FEMA, opened in 2017, benefitted property values of largely white homeowners, while predominantly black renters lacked the economic means to meet FEMA’s criteria for assistance (Erdos 2018).
More just policy responses should address zones of double jeopardy, defined by areas of low housing value that concentrates lower income residents in flood prone areas. Current policy mechanisms focusing on building codes and flood proofing not only can lead to housing displacement, but also increase asset exposure in the long term. Addressing floodplain gentrification and double jeopardy in the flood zone thus must be addressed by changes elsewhere in the urban system, namely through building accessible and public housing outside of the floodplain. The fact that the NFIP relies upon public funds from the U.S. Treasury to cover the losses of private individuals, and coastal flood protection at large increasingly demands public investments in infrastructure, makes clear that flood adaptation is a matter of public policy requiring greater procedural openness and transparency for more equitable outcomes.
Ultimately flood risks go beyond the flood zone by affecting networked critical infrastructure systems and shifting the overall demand for different land uses. While we, like many others, focus on exposure within probabilistic flood boundaries, future work must examine how the interdependent risks of critical infrastructure failures due to flooding can be addressed simultaneously with improved policies around housing affordability, managed retreat, and supporting equitable wealth generation through improved public infrastructures. Going forward, communities, policymakers, planners, and developers need to think more expansively about multiple social, environmental, and infrastructural drivers of flood risks at the scale of the whole city and the region. Future work should examine the equity of current flood adaptation and mitigation pathways and identify best practices for cooperative risk reduction that addresses the concerns of all impacted communities.