Five years after Sandy, New York is updating its flood resilience zoning

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Five years after Sandy, New York is updating its flood resilience zoning

Five years after Sandy, New York is updating its flood resilience zoning. Pictured here: A worker in the Mayor's Office of Housing Recovery's Build it Back program lifts a Staten Island home above the floodline. (Courtesy NYC DDC/Flickr)

It’s been almost five years since Hurricane Sandy pummeled New York, and the city has been steeling itself for the next storm ever since. In that spirit, the New York City Department of City Planning (DCP) is working with residents and property owners to update the emergency flood zoning it chartered right after Sandy.

The proposed Flood Resilience Zoning Update comes after the agency released its climate change design guidelines in June. In revisiting its 2013 post-Sandy rules, DCPs’ ultimate goal is to create a zoning text amendment that will help flood-proof the whole city for 2018 and beyond. Both the zoning initiative and the design guidelines are being carried out under OneNYC, the mayor’s sustainability plan.

The Federal Emergency Management Agency (FEMA) sets building standards in vulnerable areas based on the flood risk maps it produces. Cities are required to design standards around those maps. The code requires residential living spaces to be about the flood elevation, and ground-floor commercial buildings to be waterproof.D

DCP released a video, linked below, to explain the thinking behind the proposed zoning. To the city, resilience planning includes creating offshore landforms and wetlands that diffuse powerful waves, installing bulkheads and seawalls, embedding utilities in waterproof casings, and promoting flood-resistant new construction.

Flood-resilient zoning can lower the risk of floods that occur regularly in some areas and help communities plan to adapt to rising sea levels, but retrofitting is a challenge. Raising homes out of the floodplain can be expensive and foiled by existing zoning the city is working to change. The video cautions owners that this is especially true for larger buildings or attached structures: By moving their ground floor living spaces up, owners might lose a part of their house or whole apartments in multi-unit dwellings. The loss, though, is meant to mitigate future risk.

Today, the city estimates that there are 71,500 buildings and 400,000 residents in the one-percent-annual-chance floodplain, areas that could be totally devastated by a 100-year flood. By the 2050s, there could be over 800,000 people in the floodplain (the city maintains online flood risk maps that help residents determine if they live in a flood-prone area.) The DCP is holding community outreach events in vulnerable communities through the end of 2017 and 2018; information on upcoming meetings can be found here.