…by e-mail:

–The Wall Street Journal had an excellent article on the levees a day or two ago. Posted in the Corner.
Also look at this.
The added trouble with the levees (or flood walls) is that the high water creates hydrostatic pressures that forces water into the soils that support the levees. With the soils saturated with water, the support for the structure of the levees is compromised.
The engineers there, not only have to stop up the gaps but keep water from percolating through the surround soils.
One way to do that is by dewatering the surrounding soils by drilling many well points and pumping the water out of the saturated ground. Another is creating coffer dams that isolate the area. Or combinations of these.
Any solution will require a lot of heavy equipment, access to the area and time.
Sure they’ll get it done, but it will be difficult and longer than politically expedient.
–Bottom line; it depends. The key is the water flow rate in the breach, and that’s kind of tough to judge, even now. Having said that, the fact that ACE can only reach the area by helicopter is not encouraging. Reason? You simply cannot “airlift” enough “fill” fast enough for that wide, that deep. A.) the flow has to be stopped, (or darned near stopped) and B.) you have to get dump trucks in there.
Once he flow stops, you can in theory get the job done by chopper, but based on how those “supersacs” are sinking down into the abyss when the choppers are dropping them, it’s going to take one hecuva lot of trips to do the job. 10,000? 50,000? Who really knows. Based solely on what I see, it’s going to take several days at least until the hole is plugged and you can turn the pumps in the city on. THEN, you’re looking @ two more weeks until the H20’s gone.