After arguing that that levee budget cuts were not the direct cause of the specific breach on the 17th street canal that caused the flooding of New Orleans, I decided to look back and find my original source to support my contentions. After Googling for a while, the obvious occurred to me - go to the Army Corps of Engineers website (
link here) and see what they say. I've worked with many of engineers in my life, and most are well-educated techhies who take pride in their work and can be technical and detailed to a point that would bore most outsiders to tears. I honestly believe that the Katrina reports on the ACE website are simply engineering facts, details, plans and objective reports. If anyone disagrees, I'd be interest in your reasons in detail. But for now, I trust these folks like I did the weather forecasters who made us aware of the threat of Katrina.
I reviewed some of the Corps of Engineers updates and reports and learned that a "floodwall" failed, not a levee. The 17th Street Canal floodwall, which was designed to contain a surge from a Category 3 hurricane was overtopped, water poured over and undermined the dirt on the other side, and a breach occurred, Below is the status of the unwatering project with a timetable. I've copied below the contents of a Word document that is not directly linkable, but can be downloaded from the ACE home page.
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Q&As on unwatering New Orleans
Q. How long will it take to get the water out of New Orleans?
A. We are unsure. A number of factors play into this. First, Lake Pontchartrain is at roughly 4.5 feet above sea level and falling. The city is at a lower elevation so water will continue to flow into it until it equalizes.
Once the breach on the 7th Street Canal is closed, Pump Station 6 can pump 10,000 cubic feet per second.
Once the breaches are closed and all of the pumps are running, the pumps can lower the water level ½ inch per hour or about a foot per day. We can get the water level to sea level in four and a half days. The ½ inch rate assumes the lake is at normal levels. That would create pumping inefficiency, as could trash in drains and canals that feed into the pump stations.
That's a "Best Case" scenario. We don't know the conditions of all of the pumps. Fortunately most of the pump motors and controllers are at an elevation greater than 5 feet and we hope they weren't submerged. There could be other unforeseen problems.
We assume the pumps have not been submerged since most pumps are at an elevation greater than five feet above sea level.
Pumps are operated and maintained by the local sewage and drainage districts.
Q. Why did the levees fail?
A. What failed were actually floodwalls, not levees. This was caused by overtopping which caused scouring, or an eating away of the earthen support, which then basically undermined the wall.
These walls and levees were designed to withstand a fast moving category 3 hurricane. Katrina was a strong 4 at landfall, and conditions exceeded the design.
Q. How many other areas do you need to get water out of?
A. There are at least five ringed levees (areas surrounded by levees) that need to be emptied. New Orleans and Jefferson; New Orleans to Venice (Hurricane Protection project - Port Sulfur to Venice, LA); Chalmette Loop (lower 9th ward of Orleans Parish and Urbanized part of St. Bernard Parrish ); and, Plaquemines Parish non-federal levees have also been overtopped.
Q. What will be done to unwater these areas?
A. The unwatering plan will be used in these areas as well. Crews and equipment will be mobilized to breach the levees at predetermined locations and allow for gravity drainage into Lake Bourgne or other surrounding water bodies.
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I recommend that anyone who wants the real facts on the technical details of the flooding and unwatering of New Orleans and nearby parishes areas go directly to this authorative source, and stop believing rumours. Several floodwalls and levees were overtopped. Some levees sink over time, and need to be raised. To handle a direct hit by the surge of a Category 5 hurricane, all floodwalls and levees would have to be raised. The details and heights would be determined by the proposed study whose funding was cut by the Bush administration. While we agonize over the administration's failure to organize the help for the human victims, the Corps of Engineers is accomplishing amazing things already. Perhaps the Bushies could learn from them how to quickly react to disaster. No politics - just get it done!