NEW YORK - Construction of the memorial and underground museum commemorating the Sept. 11 attacks will be finished in 2011, two years later than originally planned, officials said yesterday.

The "Reflecting Absence" memorial will surround two waterfall-filled pools marking the World Trade Center tower footprints with a plaza of sweetgum and oak trees. Officials had said for years that it and a museum below street level would open Sept. 11, 2009.

The construction schedule was revised to reflect a more realistic schedule that became clear after construction began, Port Authority spokeswoman Candace McAdams said.

"We see the reality, and want to operate on responsible timelines," she said. "We'll work as aggressively as possible to complete the project as soon as possible."

The builders of the memorial initially adjusted the timetable last year, saying the above-ground plaza would open in 2009 and the underground museum a year later.

Steve Plate, who oversees the rebuilding of the trade center site for the Port Authority of New York and New Jersey, said yesterday that the schedule would be pushed back another year.

By 2009, the steel for the memorial pools would be built up to street level, he said. By 2010, the cobblestone-filled plaza surrounding the memorial pools would be "nearly complete," he said. The plaza would be open to the public by that time, McAdams said.

The entire memorial, museum and pavilion will be finished by 2011, Plate said.

See more at the 9/11 memorial's Web site via