NYC mayor seeks to flood-proof Lower Manhattan, add land

Updated 12:45 p.m. ET

New York City Mayor Bill de Blasio proposed a $10 billion plan to push out the Lower Manhattan coastline as much as 500 feet, or two city blocks, to protect the land from flooding that’s expected to become more frequent as global temperatures rise.

‘Resiliency measures’

“The new land will be higher than the current coast, protecting the neighborhoods from future storms and the higher tides that will threaten its survival in the decades to come,” de Blasio wrote in a piece published in New York Magazine. The mayor plans an announcement about “resiliency measures” later this morning.

South Street Seaport and the Financial District, along the eastern edge of Lower Manhattan, are just 8 feet (2.4 meters) above the water line, de Blasio said. The city can’t build flood protection on the existing land because it’s too crowded with utilities, sewers and subway lines, he said.

Flooded in 2012

The neighborhood was flooded in 2012 by a storm surge brought by Hurricane Sandy, which caused billions of dollars of damage to real estate and infrastructure. Its home to 90,000 residents and 500,000 jobs. The extension will secure lower Manhattan from rising seas through 2100, de Blasio said.

The extension would jut out into the East River north of the Brooklyn Bridge, up the east side to the Bowery. It would be part of an overall resiliency plan for Lower Manhattan that includes a $500 million project to fortify the area with a U-shaped expanse of grassy berms and removable storm-barriers that can be anchored in place as storms approach, de Blasio said.

On Staten Island, which also experienced devastation from the storm, the city has received $615 million in federal funding to create a protective seawall on its eastern shore. Other fortifications have been installed along the southern Queens shoreline in the Rockaways, including a boardwalk that will also act as a barrier to tidal surges.

Marine life worries

Tim Dillingham, executive director of the New Jersey-based American Littoral Society, which advocates for protecting coastal environments, said he worries about the effect of the proposal on marine habitat.

“We very rarely accept the rationale that you can sacrifice the environment for economic development,” Dillingham said by phone on Thursday. “We would want to see alternative ways to do that.”

Ideas to build some sort of seawall around lower Manhattan have circulated for years, including one proposed in 2013 by then Mayor Michael Bloomberg. The former mayor is founder and majority owner of Bloomberg News parent Bloomberg LP.

That plan, dubbed “Seaport City,” included major private sector development, which would take more time to implement, de Blasio said. This project is focused on resiliency, de Blasio said.

‘No other alternative’

Jesse Keenan, a researcher at the Harvard Graduate School of Design who advises governments on climate resilience and adaptation, said the instinct to hold back climate change with walls and other infrastructure projects can sometimes create a false sense of security at great cost and for a limited amount of time. But New York City is an exception.

“I can’t think of anywhere else in America where there would be a stronger impetus to make this kind of investment,” said Keenan, who co-authored a 2014 study on protecting Southern Manhattan’s coast. “Given the elevation and total amount of economic output and productivity from this part of the country, we really have no other alternative.”

That doesn’t mean de Blasio’s proposal will be easy. The main drawback, Keenan said, is the amount of red tape the city must clear.

Complicated coordination

“Once you talk about moving into the water, you’re talking about a level of coordination with the U.S. Army Corps of Engineers, and likely Congress and other environmental stakeholders, that could significantly lengthen and complicate it,” Keenan said. “But maybe that’s inevitable. Maybe we shouldn’t run away from that.”

The process would also include years of local land-use hearings and environmental impact studies that could delay construction until 2025 or later, de Blasio said. The mayor said residents that experienced Sandy’s devastation may want changes while supporting the concept.

“After Sandy you don’t find many climate-change deniers in New York City,” de Blasio said. “This is the existential threat, the core issue that we all must face as soon as possible.”

Related:

• Kerry says climate change may flood Lower Manhattan by 2100
• New York lays out $20B plan to adapt to climate change
• NYC planners: Storm-surge barrier may come too late

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