Mayor Michael Bloomberg, right, and artist Olafur Eliasson, tour one of Eliasson's waterfall projects, centre, at the Brooklyn Bridge in June. (Bebeto Matthews/Associated Press)

The New York City Waterfalls was apparently a windfall.

Mayor Michael Bloomberg said the public artwork by Olafur Eliasson that put four waterfalls in the East River and New York Harbor brought in an estimated $69 million US for New York City, exceeding initial expectations of $55 million. The work drew 1.4 million visitors from June 26 to Oct. 13 to view the installation off Manhattan's East Side.

"People didn't buy tickets or pass through a turnstile to experience the Waterfalls, but this exhibition brought people to areas of the city they might not otherwise ever have visited," the mayor said Tuesday in a statement.

"We've always understood that we have to encourage big, bold projects that set our city apart, and this will be increasingly important while areas of our economy are struggling from the turmoil on Wall Street."

The project was not without its problems. It generated complaints from some neighbourhood groups and businesses that said salty mist from the manmade cataracts was damaging waterfront plantings along Brooklyn Heights' popular promenade. In response, the Public Art Fund in September cut the exhibit's weekly hours in half.

Ranging from 27 to 36 metres tall, the waterfalls together spurted about 130,000 litres of water per minute.

The project was the city's largest public art endeavour since 2005, when artist Christo and his wife, Jeanne-Claude, festooned Central Park's footpaths with thousands of saffron drapes hung from specially designed frames.

More than five million people saw The Gates, including about 1.5 million out-of-town visitors. That installation was credited with injecting about $254 million into the local economy.