Draining the billions of gallons of water that have inundated New Orleans could take three to six months, substantially longer than some experts have expected, the Army Corps of Engineers said late Wednesday.
Col. Richard Wagenaar, the corps' senior official in New Orleans, said that the estimate was based on planning done as Hurricane Katrina approached and that it remained the corps' best estimate. He is directing the agency's recovery efforts.
The estimate depends on favorable weather. Additional rain or other problems could cause more delays, Wagenaar warned.
"There is a lot of water here," he said. "The news cameras do not do it justice. And I'm worried the worst is yet to come."
Public officials, meanwhile, were furious over the corps' delays. Mayor C. Ray Nagin blistered officials on television for what he called their inaction. Gov. Kathleen Babineaux Blanco scowled in irritation, saying, "I'm extremely upset about it."
Walter Baumy, a chief engineer, said that the corps was confronted by riverbeds clogged with loose barges and debris and that it could not find contractors able to maneuver heavy equipment into the flood zone. Blanco acknowledged that officials were also struggling with faulty communication. After a disheartening aerial tour of the flooded city, Blanco said she was able to reach White House officials on a satellite phone but could not connect with Army and other officials in nearby Baton Rouge.
"Part of our problem is we're not getting information delivered quickly enough," she said.
Wagenaar said the evaluations Wednesday were sobering, leading him to believe that city officials' horrific death estimates given could be accurate.
The water is 30 feet deep or more in some parts of the city, covering homes. In the city's 9th Ward, homes have shifted and floated away, leaving nothing that resembled the city grid before the storm, Wagenaar said after a helicopter tour.
New Orleans' lakes and rivers are bordered by a system of earthen levees, concrete seawalls and steel doors that are supposed to protect homes and businesses during heavy rains or hurricanes.
The city's 22 pumping stations are not operating, and most are underwater. Not until the city naturally drains a little can the corps begin restoring pumping capacity, Wagenaar said.
He said the corps planned to punch holes in levees around the city to hasten the drainage now occurring through the main breach that swamped the city after the hurricane. Levees on the Mississippi River, Lake Pontchartrain and an inner coastal waterway are to be broken open in coming days, though "we haven't decided yet how."
The pumps, which the corps will repair when it can, are a key part of the sophisticated drainage system that is supposed to keep the city dry. But they run on electricity, which is out in the city, and the pump stations' emergency power supplies may also need repair.
The first task, though, is fixing the main breach, on the 17th Street Canal, which leads from the city center to Lake Pontchartrain. The corps started to drop massive sandbags from military helicopters Wednesday.
The corps is also trying to build a road above the water to the breach, which is estimated to be 200 to 300 feet wide, and it is shutting off the 17th Street Canal to prevent any further water from flowing into the city, Wagenaar added. A contractor will use sheet piling to shut off the canal.
Corps officials think water rose over the top of the canal wall and cascaded down to its base, scouring a hole that undermined the foundation, said Al Naomi, the corps' senior project engineer in New Orleans.
"It exceeded the design surge," he said. "It just blew out the wall."
The dirt levees and reinforced concrete flood walls are designed to hold back an 11 1/2 -foot storm surge, not including waves spilling over the top. The Katrina surge is believed to have been significantly higher than that.
The flood walls and levees are 13 to 19 feet above sea level, depending on how vulnerable the area is.
The 17th Street Canal pumping station is the largest single drainage pump in the world, able to move 10,000 cubic feet of water per second. That's roughly how fast the Colorado River flows below Hoover Dam.
Although the Army Corps of Engineers builds and maintains the area's levees and flood walls, parishes and cities control the pumping stations.
The water level in Lake Pontchartrain, which was unusually high after the storm, dropped 2 feet in a 24-hour period Tuesday, said Dana Newsome of the state Department of Transportation and Development. "Obviously that means the water did go somewhere."
The corps began preparing Wednesday to fix the walls by dropping massive sandbags from Chinook helicopters, but nobody is sure the unprecedented plan to drop 500 bags will work.