And their retirements are prompting critics once again to question whether the corps can be relied upon to protect this city from future disasters.

The latest retirements include two top civilians and the New Orleans district engineer. They follow the retirement of Lt. Gen. Carl A. Strock, the agency chief. In August, Strock said he was leaving his post for “family and personal reasons.”

The departing corps officials dismissed suggestions they are leaving because of criticism of the agency after Katrina. Forensics investigations into what caused flood walls to collapse showed that flawed, past work largely caused the flooding of the central parts of New Orleans.

The officials also said they are not being pushed out by the agency’s top officials.

“If those individuals made the decision to continue to do what they were doing, we would have been perfectly happy to allow them to do that,” said Gene Pawlik, a corps spokesman in Washington.

The retirements have given critics more reasons to question the agency entrusted with rebuilding the region’s levees and flood walls and leading the effort to restore Louisiana’s badly eroded coast; the coast acts as a buffer against hurricanes.

“We’re seeing significant turnover at a time when we need consistency and experience in the leadership positions,” said Mark Davis, executive director of the Coalition to Restore Coastal Louisiana, an influential coastal lobbying group.

Ivor van Heerden, a levee expert with Louisiana State University who has fought with the corps over what caused the engineering failures after Katrina, said the perception is that the officials may be stepping down because of missteps they made.

“The appearance is — and it is only an appearance — that this is more corps of engineers (officials) falling on their swords,” van Heerden said.

The corps faces numerous lawsuits alleging its designs caused the flooding of New Orleans. Also, the agency has missed deadlines in its reconstruction work and has appeared, at times, unwilling to accept fault.

Last month, Col. Richard Wagenaar, the New Orleans district’s engineer chief who was assigned his post one month before Katrina hit on Aug. 29, 2005, asked the Army to let him retire next summer.

He cited the “mental challenges and physical challenges” of handling the district since Katrina for his decision. He was unavailable for comment last week.

Dan Hitchings, a civilian who oversaw the agency’s reconstruction mission after Katrina, said he is retiring at the end of January. He said he doesn’t see the change in leadership affecting the agency’s ability to get the job done.

“It’s not just the leaders who have the history, mostly it’s the people who work for us, and they’re not changing,” Hitchings said. “We’re going to have an orderly transition in leadership.”

The third top engineer to retire is Greg Breerwood, the senior civilian in the New Orleans district with 37 years of experience.

He said the corps is about to start “the next phase” of long-term flood and hurricane protection for Louisiana. So, he added, “It’s best that someone come in to take that next phase all the way to completion.”

Breerwood’s last day is set to be Jan. 3.

Van Heerden called Breerwood “possibly the most powerful person in the New Orleans district” — the direct contact between staff and the district engineer.

Davis, who is with the coastal lobbying group, said he doesn’t believe the changes are due just to “Katrina fatigue, and I don’t think it’s the corps clearing the decks for action.

“Some of it is personal, some dealing with the complexity of running the corps’ business,” he said, “but the real thing is that it demonstrates just how poorly the corps is set up to handle the public’s business at times like this.”