A new barge-mounted pool will serve more than one New York borough.

There's a big difference - namely sanitation - between swimming in the lower portion of New York's East River and swimming on it. The latter, a novel concept, has been made possible with the opening of a "floating pool," which recently docked off the Brooklyn shore.

The Floating Pool Lady is a decommissioned cargo barge with a 25-meter, 4-foot-deep swimming pool nestled into its decks. The pool/barge, with a capacity for 175 swimmers, opened on July 4, moored between industrial Piers 4 and 5 off the shore of New York's most populous borough. Complete with a spray pad, recreational deck space, on-board changing and locker rooms, a snack bar and a stunning view of lower Manhattan, the floating pool has been a decades-long dream of Ann Buttenwieser, a former city waterfront planner.

"My hopes are to serve the communities that don't have swimming facilities and to have New Yorkers finally realize they live on an island," says Buttenwieser, who has overseen the private fund-raising of nearly $6 million to float the pool project. "People are coming to this shore for the first time in 100 years. Until six months ago, this was totally industrial waterfront."

The city is providing transportation for Brooklyn residents to and from the floating pool - which attracted more than 1,000 visitors to its Independence Day opening - and Buttenwieser's nonprofit group, the Neptune Foundation, has an agreement with the Brooklyn Bridge Park Conservancy to have the barge stationed on the shores of the fledgling park. Park planners envision transforming 83 acres of blighted industrial property, including 1.3 miles of waterfront, into city parkland. "The floating pool was one way they can have an interim use here," says Buttenwieser. "Now they can say to people, 'Hey, this park is really going to happen.' " But the barge may not be in Brooklyn long, as Buttenwieser would like to see it used by other underserved neighborhoods. "The objective is to move it someplace else next summer. We're looking at the Bronx right now," she says.

Buttenwieser first devised the floating pool concept 27 years ago while stumbling across some old records of New York's "floating baths," a series of quartered-off, seasonably movable pools along the East and Hudson Rivers. The baths were used for sanitation (bathing) and recreation (swimming), both of which were hard to come by around New York's tenement districts in the late 19th and early 20th centuries. The floating baths lost popularity after threats of contamination and as the city began building filtered pools inland.

Though the floating pool concept isn't new, Floating Pool Lady architect Jonathan Kirschenfeld says, the idea of marrying pools and barges for community use is.

"We put together a heavy cross-discipline kind of team," which included a structural engineer, a naval engineer and a pool consultant, he says. "Basically it was a boat from the deck down and a building from the deck up. One guy would know about barges, and another guy would know about pools, but nobody knew about pools and barges." As a general rule, Kirschenfeld says, everything below deck, including all the boat and pool equipment, was built to meet U.S. Coast Guard standards, while everything above deck was built to satisfy public assembly standards. "As you can imagine, it was a regulatory nightmare," Kirschenfeld says.

For Kirschenfeld, the reward of seeing New Yorkers flock to the community pool is well worth the effort of seven years fraught with countless delays, some even caused by Hurricane Katrina after the barge was purchased in New Orleans. "It was one of the most satisfying moments of my career watching people who waited since 5:30 in the morning to be first on the barge," he says. "I was standing up on what we call the porch, facing the land, watching people stream up these 90-foot-long gangways with big grins on their faces. It was spectacular."