East river swimming could become a reality. The city’s rivers, harbors, and bays are cleaner than they’ve been since the Civil War.

“Why couldn’t we envision this kind of waterfront, not as an amenity in exchange for building, but for its own sake?” she asks. “This is the kind of waterfront we should have a lot more of, whether or not it’s residential.” 2 Trees representatives say the River Street plan addresses both of those concerns: It would help bring more life back to the waterfront by creating marshes, oyster beds, and feeding and nesting places for species such as Atlantic blue crab, blue fish, and mussels. And from a resiliency standpoint, the design of the public park would help stem flooding in the towers because its expanded soft shoreline and pier will break wave action and absorb flood waters, while the towers will keep sensitive electrical and mechanical equipment above the floodplain. The plan also could also help unlock new uses for the city’s waterfront, which advocates and city officials have called the “6th borough” because of its untapped potential. Even politicians gotten in on it: In 2011, then-Mayor Michael Bloomberg launched a plan for new waterfront parks and a ferry service, saying, “Our waterfront and waterways—what we are calling New York City’s ‘Sixth Borough’—are invaluable assets. And when our work is complete, New York City will again be known as one of the world’s premier waterfront cities.”