In Manhattan, however, they would stick up prominently between a busy street and the promenade. After being set up, they would eventually be decorated by artists in a process city officials call “beautification.”

Not everyone who has beheld them agrees.

“I saw the barriers in Red Hook, and they are not attractive,” said Catherine McVay Hughes, a former chairwoman of Community Board 1, which encompasses the financial district and the seaport. “They’re not contextual with the South Street Seaport.”

The barriers would be “atrocities,” said Alice Blank, a TriBeCa resident who heard city officials present their plans to the community board at a recent meeting. “I guess what they were saying is, we’re going to put down these unsightly blocks and we’re going to paint them in the fall.”

City officials said the barriers can last up to five years and are worthy stopgap measures. “Our goal is to bridge the gap between the current hazard and permanent mitigation,” said Benjamin Krakauer, an assistant commissioner at the Office of Emergency Management.

While they seem like a makeshift solution to protecting urban centers, New York is not the only city to deploy them — other cities, including New Orleans and Los Angeles, have also used the barriers as temporary fortifications.

They filled gaps in levees in New Orleans as Hurricane Katrina approached in 2005. In Los Angeles, the United States Army Corps of Engineers installed a three-mile line of them on a bank of the Los Angeles River out of concern about flooding from El Niño storms in 2016.

But after complaints from cyclists and equestrians about the barriers blocking access to a bike path and horse-riding trails, the Corps removed many of them after the El Niño threat had passed.