The rushing water tore 4 to 6 feet into the embankment, then cascaded the remaining 10 to 15 feet to the street, said Jeffrey Jensen, flood control program manager for the corps at its Washington headquarters.
Engineers hope the water gushing through the levee will slow or stop once the water in Lake Pontchartrain recedes to pre-storm levels and below the level of the breach.
"It's not subsiding as much as we'd hoped," Jensen said.
The Corps' plan to dump rocks or containers of sand into the gap from the air is a variation on what Stockton described as the standard procedure for mending a levee.
"You typically go in and start dumping large rocks or boulders to slow the flow of water down, which will slow the amount of erosion taking place," he said.
Smaller rocks, gravel and sand can then be poured in to seal the break. Sometimes a temporary ring levee is built outside the breach, often on higher ground where access is easier and the water flow slower.
Access to a levee break can be a problem. Some levees are designed to support truck traffic, but not this one. Barges are better if they can be moved close enough without being drawn into the gap.
"We're working on whether we can get a barge up there," Hecker said. "That's difficult due to the relatively narrow width of the canal."
Once the leak is plugged, the corps will turn to pumping.
The city's 22 drainage pumps can't do it fast enough on their own, so the Corps is prepared to bring in high-volume portable pumps to assist if the Federal Emergency Management Agency calls for them.
It would take "days or weeks" to drain the floodwater to a point where the city's pumping stations could operate again, Stockton said. Some pockets of water could remain for months.
In the meantime, tens of thousands of homes and businesses are steeping in seawater, sewage and other waste. ...............***
A couple of quotes I found on other posts sum it up well:
"The 'Big Easy' is now the 'Big Nasty.' "
... It's like The Day After Tomorrow, Dawn of the Dead, and Escape From L.A. all rolled into one...