Transportation security officials initially were skeptical that a fabric device would hold back floodwaters, said DHS project manager Fortune. But that skepticism is fading, he said.

Developers said this week's disaster in New York will likely increase interest in the Resilient Tunnel Project.

"While we don't want to ride the back of a disaster, it's certainly our hope that people will look at this technology," Holter said. "This may be the worst storm ever recorded in the last 100 years, but that's no reason that we won't have another storm that will cause as much damage."

Should DHS have expedited development of the plug?

That's a hard question to answer, said terrorism expert Brian Jenkins, director of the National Transportation Security Center at the Mineta Transportation Institute in San Jose, California.

While officials can envision a wild spectrum of vulnerabilities, they have finite resources to address them, he said.

"There are lots of solutions that become obvious following a disaster of some type," Jenkins said.

"To a certain extent, security is almost always reactive, because it's hard to justify the costs of deploying technology for things that have not occurred. And once they do occur, it's almost impossible to resist spending the money on the technology to prevent a reoccurrence.

"That's the axiom. It's a sad one, but that's the reality."