Building into the East River: Elusive Fix for Seaport and FiDi Flood Protection

Detail from a draft sketch of one option for extending land into the East River, which envisions replacing the FDR Drive with an at-grade roadway. Credit: Mayor's Office of Coastal Resiliency/NYCEDC

Fifty years ago, long before climate change was on the radar of City Hall and most everyone else, the city under Mayor John Lindsay had plans to extend Lower Manhattan into the East River, a kind of Battery Park City east called Manhattan Landing [1]. Though officially approved, the plan went nowhere. Or so it might have seemed. 

Fast forward to the devastating impact of Hurricane Sandy in 2012. Mayor Michael Bloomberg revived the idea with Seaport City [2], a proposed 1.3-mile levee on the East River meant to protect Lower Manhattan’s east side from future flooding, and be financially self-supported by real estate development. 

That proposal, too, was scrapped, but the concept of building parts of the Seaport and Financial District into the river has lived on in yet another detailed study. This one, announced in early 2019, is the de Blasio administration’s Lower Manhattan Coastal Resiliency Project [3], which views land mass extensions as the only guard against the catastrophic consequences of climate change to those neighborhoods.

That complex and costly solution is necessary, project officials say, because space along the waterfront in those areas is too narrow for conventional protection measures, as well as the drainage infrastructure that goes with it. 

“We’ve looked at this in a good amount of detail and an entirely inland project that provides the daily tidal flooding, the access, the maritime use, and the coastal defense is just not there,” Jordan Salinger, an advisor with the Mayor’s Office of Climate Resiliency [4], told Community Board 1’s Environmental Protection Committee last month.

Such a massive undertaking, officials say, could take two decades to complete, at a cost well beyond what the city alone can fund. Then there are the environmental and regulatory hurdles that lie ahead for any plan that calls for filling in part of the river. As a result, resiliency measures for the Seaport and FiDi lag far behind those moving forward for the Battery and Battery Park City, as well as a section to the north, from the Brooklyn Bridge to Montgomery Street.

Federal and state environmental regulators have already nixed the 500-foot land extension (about two city blocks), earlier envisioned by the city, officials say. “We are currently exploring more modest widths approximately half that 500 feet or less,” a city Economic Development Corp. spokesman said in an email to the Trib.

According to the city’s estimates, average daily high tides in the 2050s will reach 2.5 feet above today’s levels, and by the 2080s, those tides will be flooding the area almost daily. Looking ahead to 2100, they are aiming to protect the Seaport and Financial District from flooding that they say could reach as high as 20 to 25 feet. 

“If we do nothing, climate change threatens the existence of Lower Manhattan, with impacts extending throughout the entire city and region,” the Mayor’s Office of Climate Resiliency said in a report.

The de Blasio administration has committed $500,000 to the project, roughly estimated to cost from $5 billion to $7 billion, excluding whatever is actually built on the landfill. The city hopes much of the remaining funding will come from the federal government (the American Jobs Act, in particular) and a state bond act, yet to go before voters. Other revenue, city officials say, might come from developers, and new buildings up to 5- and 6-stories tall at the Seaport and up to 1,000 feet high near Wall Street. 

Last month, the city convened a remote “open house” to get public feedback on, among other things, desired uses for new waterfront acreage as well as public space beneath the FDR Drive. (The future of the overpass itself is in question and taking it down as part of a future flood protection program is under review.)

But other critical unknowns remain, says Alice Blank, chair of CB1’s Environmental Protection Committee. In a phone interview, she questioned how currently contemplated plans dovetail with those already underway on either end of the contemplated project. And she said a better case needs to be made for designing defenses against such extreme flood heights. “We’re always shown this segment [of the protection plan] but we never get a global understanding of what the approach is. And do we need to go up to 23 feet for a 100-year flood? Is it consistent with what will be built just to the north?”

Then there is the question of what will protect those neighborhoods in the decades before a levee is built.

Two years ago the city devised measures [5] against “low-level, high-occurrence coastal floodings” up to four feet high—below the flood levels of Hurricane Sandy. They include sand-filled wire mesh bags called HESCO barriers, now in place, and water-filled Tiger Dams that are deployed in gaps between those barriers, days before a storm is projected to strike. Those protections were said to be good for five years.

“Nothing additional is planned at this time, and we will try to make the current installation last as long as possible,” Christina Farrell, spokeswoman for the city’s Office of Emergency Management, told the Trib in an email.

Comments? Write to editor@tribecatrib.com