United States: Shelter From The Storm: Ambitious Resiliency Plans For New York City

Even before Hurricane Sandy mercilessly exposed New York city's susceptibility to rising sea levels and violent storms, planners, architects, engineers, and policy makers have been at work studying the city's vulnerability to natural disasters and devising plans to make the city more resilient. Recently, a number of environmental and professional organizations have released post-Sandy resiliency plans, and earlier this month, Mayor Michael Bloomberg announced an ambitious and comprehensive $20 billion resiliency plan.¹

Before the city's plan was released, the New York Chapter of the American Institute of Architects issued its post-Sandy report in May, "Building Better, Building Smarter: Opportunities for Design and Development," which focused on preparing transportation and infrastructure networks for the next severe weather event, updating local and national regulations related to housing in flood zones, adapting critical buildings (hospitals, data centers, etc.) and commercial buildings to withstand climate effects, and building more resilient city harbors and waterways.²

A week before the city's plan was released, the New York Building Congress released "Risk & Resiliency After Sandy," which recommends upgrading the city's power grid, streamlining emergency planning and response, and improving building codes.³ The following week, the city-commissioned Building Resiliency Taskforce issued its report, which proposes numerous technical, regulatory, and code changes for buildings, infrastructure, planning, and emergency response.⁴

The city's 440-page report, "A Stronger More Resilient New York," details more than 250 strategies and recommendations to adapt the city to weather-related threats, including sea-level rise, storm surges, heat waves, wind, and increased rainfall. The report covers various critical areas, including coastal protection, buildings, economic recovery, insurance, transportation, utilities, and environmental protection and remediation.⁵

The report also proposes the construction of engineered barriers to protect the city's coast, including bulkheads, wetlands, levees and floodwalls, and also covers even more ambitious and controversial ideas, such as "Seaport City," an expansive landfill off of the Lower East Side modeled after Battery Park City.

On Feb. 28, 2013, our article discussed Governor Andrew Cuomo's proposal to purchase property in the floodplain damaged by Sandy.⁶ While the city's plan mentions buyouts as a possible, limited strategy, the focus of the city's plan is to make the highly developed urban area within the floodplain more resilient to rising seas. This article focuses on the revisions to the FEMA floodplain maps that show that more of the city is in harm's way, and the city's proposals to protect new and existing buildings in the floodplain.

Updated Floodplain Maps

In 1983, FEMA produced its first floodplain maps of New York, called Flood Insurance Rate Maps (FIRMs), which identify the land falling within the 100-year and 500-year floodplains—that is, areas that have at least a 1 percent and 0.2 percent chance, respectively, of flooding or wave action each year, and not, as often mistakenly said, an area that will flood once every 100 or 500 years. Put another way, the 100-year floodplain has a 26 percent chance of flooding in a 30-year period (a common length of a mortgage), 43 percent chance in 60 years, and a 63 percent chance of flooding in a 100-year period, all far greater odds than a fire or other potential disasters.⁷ Further loading the dice, FEMA's maps have been developed using historical data and thus have not considered future risks such as rising sea levels.

The FIRMs show the associated Base Flood Elevation (BFE), which is the height that floodwaters could potentially rise in a base (1 percent chance) flood, and also divide the floodplain into two categories of advisory hazard subzones, V and A zones. V zones are subject to high velocity waves, and A zones are just subject to storm surge flooding without dangerous wave action. Under the 1983 maps, 33 square miles in New York City were within the 100-year flood plain. Using 2010 data, roughly 210,000 people lived in those areas, as well as the entirety of the city's wastewater treatment plants, almost half of its power plants, and about 35,500 buildings.⁸

In 2007, well before Sandy, the city had formally requested that FEMA update the outdated flood maps covering New York City, though FEMA's overall mapping revision program suffered from delays. In January 2013, in response to Sandy, FEMA released Advisory Base Flood Elevation (ABFE) maps for coastal areas, based on incomplete surveys. In June 2013, FEMA released Preliminary Work Maps (PWMs), which also are draft products based on the ABFE data and do not include updated riverine data. The PWMs will be replaced by the "Preliminary FIRMs" by the end of 2013 which will show both coastal and riverine flood hazards. Final FIRMs are scheduled to be released in 2015. Whichever update is the most recent for a given area is considered the best-available flood hazard information at that time.⁹

The June PWMs reveal stark changes in the physical terrain and population density since 1983. Although more precise data resulted in less area within the wave danger V-Zone, the revised 100-year floodplain now covers almost 50 square miles (an increase of 45 percent), with expanded zones in all five boroughs. Most troubling is that about 67,700 buildings are in the new floodplain (an increase of 90 percent), about 196,700 residential units (increased over 60 percent), and almost 400,000 people live in the 100-year floodplain (up 83 percent).¹⁰ Although its percentage of the population living in the floodplain is only 5 percent, New York City has more people living in the floodplain than any other city in the country, and the greatest floodplain population density.

Building Code Proposals

Given that the new maps demonstrate that thousands of structures are in harm's way, a principal goal of the city's plan is resiliency at the building level. As set forth in the city's report, damage to buildings varied greatly based on a building's height, construction type, location, and age.

The city's construction codes have incorporated flood resiliency since the 1983 FIRMs. State law also requires that the city's codes at least meet the standards defined by the State's Building Code. In 2010, the state, and therefore the city, began requiring a higher-elevation building standard than the one set at the federal level by the National Flood Insurance Program. These requirements are incorporated into Appendix G of the city's Building Code, which requires new and substantially improved buildings¹¹ in the 100-year floodplain to meet an incremental height above the BFE known as a "freeboard."

BFE plus freeboard is called the Design Flood Elevation (DFE). For instance, one and two-family homes must add two feet of freeboard to the BFE and non-residential buildings must add one foot of freeboard. For new or reconstructed residential buildings in the 100-year floodplain, Appendix G prohibits (among other things) living areas below the BFE; whereas, for new or reconstructed commercial buildings in the floodplain, it either prohibits floors below the BFE or requires them to be made watertight. Requirements differ based on whether the building is in an A or V flood zone.¹²

Sandy flooded an area that included nearly 90,000 buildings—9 percent of the city's building stock—but the damage was not uniform. According to the city's research, a comparatively small number of buildings had significant structural damage or were destroyed, and the vast majority of those with structural damage occurred in areas subject to wave force. Most damage from Sandy was from stillwater flooding of building systems, often located in basements, and building contents. Although not structurally destroyed, those buildings were nevertheless rendered uninhabitable without major repairs.

Building age, height, and construction type were also predictors of damage. Structures built before the 1961 zoning resolution and the 1983 FIRM maps were more heavily damaged than newer buildings. Taller buildings fared much better than low-rise houses, and "combustible" buildings (made of wood studs and similar materials) were more heavily damaged than "non-combustible" buildings made of steel and concrete. In sum, the most vulnerable buildings were one-story combustible buildings built before 1961.¹³

The recommendations in the city's report are divided between: (1) Requiring new and rebuilt structures to meet the highest resiliency standards; and (2) Encouraging the retrofitting of existing buildings.¹⁴

New and Rebuilt Structures

A principal goal is to amend the Zoning Resolution and Construction Codes to allow for buildings to be built to withstand flooding and other disasters. For instance, the Zoning Resolution would be amended to allow buildings to be elevated without penalization for exceeding zoning height limitations, and the Building Code would be amended to require sewer backflow prevention connections, to require the sealing of points of water entry, and to permit cables carrying telecommunications services to reach elevations above the DFE.

Second, the city proposes various citywide and neighborhood land use studies and zoning amendments to voluntarily promote more resilient construction, such as more flexible height measurements to allow underneath parking; enabling modern construction on smaller lots; allowing additional top floors on buildings; and permitting greater flexibility for accessibility features. Because certain flood resistant construction techniques may negatively affect urban design, DCP is currently working on design principles, to be released later this year.¹⁵

Retrofitting Existing Buildings

Altering existing buildings, especially in a dense, urban environment, is more of a challenge than building new, resilient structures. The city's plan includes mainly policies to encourage building owners to adopt "Core Flood Resiliency Measures"—such as elevating or protecting critical building equipment such as fire protection, heating, ventilation, and electrical systems—through loans, grants, and other funding incentives. Larger buildings over seven stories would be required to complete Core Flood Resiliency Measures by 2030. Public housing, hospitals, and nursing homes would be subject to different requirements.

Another initiative proposes requirements to amend the Construction Codes to protect against utility service disruptions, such as requiring by next year that high-rise multifamily buildings have common access to potable water during emergency situations, and by the end of this year, requiring exit lighting to continue functioning during an extended blackout. The codes will further be amended to allow buildings to comply with new practices regarding voluntary backup power generators and the creation of "building emergency plans," as well as encouraging large commercial buildings to pre-negotiate with service providers about disaster recovery agreements.

Conclusion

The city's resiliency report is a thorough effort to prioritize and facilitate the implementation of necessary measures to maintain New York's stature in the face of a hostile climate, and all but rejects the concept of retreating from coastal areas, except in narrow circumstances. Although a comprehensive resiliency effort was long due, recent catastrophes like Hurricanes Sandy, Irene, and other lesser yet still destructive storms have made the concept of adapting to our changing climate and rising sea levels a priority of policy makers and the public alike.

While many of the legal and policy measures will require environmental review and legislative action by the City Council, the policy and code revisions are largely sensible and cost effective in the long-term, and should be implemented relatively quickly. If anything, many will debate whether the measures look far enough into the future and consider the worst long-term climate change scenarios. Whether FEMA's BFEs sufficiently account for future risk and rising seas should also be carefully analyzed by scientists and policy makers to make sure the requirements are sufficiently protective. More ambitious engineering measures, such as the proposed flood gates, levees, and landfills, will require a longer time frame to debate and plan, significant capital expense, and lengthy and complex environmental permitting. 

Footnotes

1 Mayor Michael R. Bloomberg, The City's Long-Term Plan to Further Prepare for the Impacts of a Changing Climate (June 11, 2013), available at http://www.nyc.gov/portal/site/nycgov/menuitem.c0935b9a57bb4ef3daf2f1c701c789a0/index.jsp?pageID=mayor_press_release&catID=1194&doc_name=http%3A%2F%2Fwww.nyc.gov%2Fhtml%2Fom%2Fhtml%2F2013a%2Fpr200-13.html&cc=unused1978&rc=1194&ndi=1.

2 American Institute of Architects New York Chapter, "Building Better, Building Smarter: Opportunities for Design and Development" (May 2013) available at http://postsandyinitiative.org/wp-content/uploads/2013/05/Post-Sandy-Report_Full.pdf.

3 New York Building Congress, "Risk & Resiliency After Sandy" (June 2013) available at http://www.buildingcongress.com/research/sandy/01.html.

4 Urban Green Council, New York Chapter of the U.S. Green Building Council, "Building Resiliency Task Force, Report to Mayor Michael R. Bloomberg & Speaker Christine C. Quinn" (June 2013) available at http://www.urbangreencouncil.org/buildingresiliency.

5 PlaNYC, "A Stronger, More Resilient New York," (June 2013) available at http://www.nyc.gov/html/sirr/html/report/report.shtml.

6 Christine Fazio and Ethan Strell, "Government Property Acquisition in Floodplains After Hurricane Sandy," NYLJ, Feb. 28, 2013, available at http://www.newyorklawjournal.com/PubArticleNY.jsp?id=1202590055801&thepage=1.

7 A Stronger, More Resilient New York" at 24; Presentation, New York State Dept. of Envir. Conservation, Floodplain Management Section, Bureau of Flood Protection and Dam Safety, available at http://www.dec.ny.gov/docs/administration_pdf/crsintro.pdf.

8 "A Stronger, More Resilient New York" at 23.

9 Federal Emergency Management Agency Reg. II, Coastal Analysis and Mapping, available at http://www.region2coastal.com/understanding_the_data.

10 "A Stronger, More Resilient New York" at 25.

11 A substantially improved building is one in which the cost of alteration is greater than 50 percent of the previous value.

12 "A Stronger, More Resilient New York" at 72–73.

13Id. at 24.

14 Id. at 69–70.

15 Id. at 81.

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