Landrieu made the announcement Tuesday at a news conference near the 17th Street Canal levee in New Orleans that was breached after Hurricane Katrina.
"We cannot protect our communities without effective leadership and competent management," Landrieu said.
While she did not question Van Antwerp's qualifications, Landrieu said she wanted assurances of reform at the Army Corps before she will support his nomination. "I want to make sure that he understands the need for integrated engineering and essential levee funding," she said.
President Bush nominated Van Antwerp in February to replace Lt. Gen. Carl Strock, who resigned in August.