Massive floodgates designed to better protect the heart of New Orleans from the type of storm surges that breached levees during Hurricane Katrina may not be installed until July, more than a month after hurricane season starts, a top Army official said Friday.

But large storms are rare before August, and the Army Corps of Engineers said it has a plan to reinforce the levees if another major storm threatens any earlier than that.

"We're trying to communicate this to the public because we understand they need to know where we are, but we also need to reassure everyone that we can provide the level of protection we promised," said Col. Lewis Setliff III, who is overseeing repairs to the city's entire levee system.

The Corps is installing the floodgates to protect weakened levees along three major drainage canals that channel rainfall from city streets into Lake Pontchartrain.

During Hurricane Katrina, the storm surge caused the lake to rise by more than 7 feet (2 meters) and exerted pressure on the levees, which eventually gave way, inundating large parts of the city.

When closed, the floodgates will block storm surges from entering the canals, but they also will be equipped with pumps that would at the same time allow some rain water to be drained into the lake.

Some Louisiana politicians harshly criticized the delays.

U.S. Sen. David Vitter, a Louisiana Republican, called the announcement "a huge disappointment" and said the Corps' leadership had "completely failed."

"I have been told for months that our system would be considerably stronger this season than the day before Katrina ... I no longer have confidence in that being the case," Vitter said.

If another major storm threatens before the work is done, the Corps plans to install braced walls of steel sheet pilings at the site where the gates are to be built.

Such a system was used effectively along two canals during Hurricane Rita, although Rita hit far to the west, near the Texas border, meaning sea levels rose far less than during Katrina.

In all, Setliff estimated that the Corps had finished 81 percent of the repair work on 170 miles of eroded or broken levees.