NEW ORLEANS—Every five minutes or so, an Army Blackhawk helicopter hovered 50 feet above the collapsed 17th Street Canal levee Friday and dropped a 3,000-pound bag of sand. Each one vanished into the water, showing no apparent results.
But after several false starts, the Army Corps of Engineers said their levee repair efforts are slowly taking hold.
If there is no more rain, the breaches in New Orleans' all-important levees could be closed by Sunday, said engineer Don Basham, chief of the engineering division, from headquarters in Washington.
Pumping the water out of the city is another matter.
The Corps predicts it will take days before workers can turn on the pumping system that moves overflow water through the city's canals back and forth to Lake Pontchartrain and the Mississippi River.
New Orleans' complex canal system failed in the wake of Category 4 Hurricane Katrina, when rising waters in the lake ripped holes in vital retaining walls. Lake water swamped the city, which is below sea level, and swallowed homes up to their rooftops.
While it will likely be months before the city is dry again, Army Corps officials said the sand-bag drops at the 17th Street Canal are one of several innovative steps being taken by soldiers, contractors and volunteers to fix the problem.
On one end of the canal, adjacent to the lake, workers are using a pile driver to erect a wall more than 100 feet long to stem the flow of water. The sandbag drop is shoring up the damaged levee, a sloping piece of land built from dirt, concrete and steel that's now drowning in lake water. And still other areas are being filled with sand and gravel.
"We're using a variety of materials, adapting the engineering to what we can find," said Walter Baumy, Army Corps chief of engineering for the New Orleans District.
They've trucked in gravel, sand and even ground-up road pavement from the storm's debris. "We're not sticking cars and motors and all that stuff in there," said Basham. "But normally we'd be pretty picky about the sand and gravel gradation."
But this is an emergency, he said.
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At the London Avenue Canal, the other major breach in the city's water control system, the Corps is walling off the lake with steel piling and filling in the nearby breach with gravel and sand.
Corps officials said they are planning to close both major breaches by Sunday.
Once the holes in the levees are repaired, the city's repaired pump system, plus additional portable pumps, must drain the city.
That process will likely take weeks.
Meanwhile, sandbag-heaving helicopters are the most visible portion of the levee repair effort—an innovation begun when heavy equipment couldn't reach the breaches before the Corps built roads to truck in gravel and other material.
The original idea was even grander—to drop 5-ton bags from heavy Chinook transport helicopters. But emergency coordinators commandeered those choppers for search and rescue missions.
So, instead, they are dropping 3,000-pound bags from lighter weight Blackhawk helicopters.
Between those efforts and the natural drop in the lake's level, Baumy offered a guarded analysis in a daily briefing Friday with the caution and understatement of a project manager sobered by seeing sections of his system implode under Katrina's fury just five days earlier.
"The lake has receded to within a foot of normal levels. We're still working to get the water out of the city."
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(Adams reported from New Orleans. Rosenberg wrote the story from Miami.)
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(c) 2005, Knight Ridder/Tribune Information Services.
GRAPHICS (from KRT Graphics, 202-383-6064): 20050831 KATRINA levee, 20050902 KATRINA pumps
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