How New York City is Boosting its Flood Resilience after Sandy

October 30, 2017

Five years ago Hurricane Sandy made a sharp left turn and slammed into the coast of New Jersey. As a Category 2 storm shortly before landfall, it was the largest Atlantic hurricane on record by diameter; it impacted the East Coast of the United States from Florida to Maine and inland as far west as Michigan and Wisconsin. While a total of 24 states were affected, Hurricane Sandy will be remembered not for wind damage, but flooding.

In New Jersey, 50 feet of the Atlantic City Boardwalk vanished and half of Hoboken was inundated. Battery Park in Lower Manhattan experienced a storm surge 2.8 meters above the mean tidal level; parts of Lower Manhattan flooded and seven subway tunnels under the East River were submerged. AIR damage survey teams recorded considerable devastation in low-lying coastal areas of the outer boroughs of Queens, Brooklyn, and Staten Island. Sections of these boroughs have always been flood-prone, but they can expect flooding to become more frequent and more severe as sea levels continue to rise.

A recently published study found that sea levels in the vicinity are expected to rise 5 to 11 inches between 2000 and 2030. The city’s huge 100-year floodplain is home to about 400,000 residents—and by the 2050s it is estimated that this number could more than double. The 100-year floodplain also currently contains 71,500 buildings, representing a significant amount of exposure at risk. The city has met this challenge with a series of initiatives intended to improve its resilience, among them:

  • Flood Resilience Zoning created by City Planning following Sandy, which is also working with communities throughout the floodplain to identify zoning and land use strategies to reduce flood risks
  • A comprehensive Climate Change Program developed by the New York Department of Environmental Protection and the City Mayor’s Office that requires planning and development to take into account and respond to climate change–related risks
  • An online Flood Hazard Mapper  developed by the New York City Department of City Planning to provide a comprehensive overview of the coastal flood hazards threatening the city today and indicate how they are likely to increase with climate change
  • A residential flood insurance affordability study initiated by the Mayor’s Office of Recovery and Resiliency to better understand how property owners and renters and flood insurance rates may be impacted by new flood maps being prepared by the Federal Emergency Management Agency (FEMA) and by recent legislation passed by Congress

Significantly, in a timely response to the disaster, President Obama’s Hurricane Sandy Rebuilding Task Force launched an innovative design competition to develop implementable solutions in and around the metropolis. Rebuild by Design harnessed innovation, global expertise, and community insight, and its success has inspired other efforts including the Global Partnership for Resilience. It also led to the formation of the Rebuild by Design organization, which helps cities and communities around the world become more resilient through collaborative research and design.

AIR contributed to Blue Dunes, one of the ten finalist projects in the original Rebuild by Design competition. Of these finalists, seven projects were selected for funding and are now early in the process of being implemented. The Hudson River Project and New Meadowlands are New Jersey–focused, Resilient Bridgeport  will benefit Connecticut, Living Breakwaters and Living with the Bay support Staten Island and Nassau County, and The Big U and Hunts Point Lifelines aim to protect New York City.

Between them, these projects demonstrate a wide range of bold and innovative measures, from a necklace of offshore breakwaters to various hard infrastructure and soft landscape solutions. The most ambitious is The Big U—a 10-mile protective system for Lower Manhattan running from West 57th Street to The Battery, and back up to East 42nd Street. This is not to be a massive (and ugly) defensive structure, but rather a landscaped network of berms and deployable walls protecting a series of physically independent flood protection zones offering waterfront access.

The city has been aware of its growing flood risk for decades, but major initiatives—such as the storm surge barriers for the harbor entrance first mooted following Hurricane Debbie in 1960—were never actually implemented. Hurricane Sandy was another wake-up call. This time city authorities responded and projects large and small are planned, but five years after Sandy, few have actually begun construction and fewer still have been completed. Funding and planning issues have slowed momentum and memories and the imperative to act appear to be fading.

The ideas behind the Rebuild by Design projects are brilliant in theory, and it is great that the city is pursuing such a wide variety of solutions rather than relying on a single strategy. But these projects will do nothing to improve New York’s resilience if they cannot actually be carried through to completion. Opportunity is slipping away, and while we all hope that these measures will not be put to the test for many years, the next major flooding event could occur at any time.


Read “Insights into Damage and Vulnerability from AIR’s Sandy Survey Teams“ for discussion of survey findings

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