Less than 8 inches of waterThat much water would just cover your ankles. That much water would barely be enough to float a flatboat.
And that's how much water the MRGO contributes to hurricane storm surge.
I know it's incredibly popular to say that St. Bernard and the Lower Ninth Ward flooded because of the evil Mississippi River Gulf Outlet. I know that the press, politicians and people from all over blame the MRGO for the catastrophic flooding that occurred there, but the science of the situation says otherwise.
Everything I write now is detailed in a paper titled, "Note on the Influence of the Mississippi River Gulf Outlet on Hurricane Induced Storm Surge in New Orleans and Vicinity." You can read if for yourself here.
Both before and after Katrina, engineers and scientists investigated the impacts of the MRGO on hurricane protection. Using the latest computer modeling and laser surveying techniques, they ran a variety of hurricanes through a digital rendering of southeast Louisiana. They ran the existing conditions, and then they ran the model with the MRGO completely filled to marsh elevation. They also ran it with a gate closure at the southern end of the MRGO. They ran hurricane models that mimicked Betsy, Katrina and other historical and synthetic storms.
And here is the result: the difference in storm surge with the MRGO was, at most, less than 8 inches. In most places, the difference was less than 4 inches.
Hardly a smoking gun, is it?
The primary author of the paper I refer to is Dr. Joannes Westerink of Notre Dame, a worldwide authority in hydraulic modeling. It is part of the government's official IPET investigation of what went wrong in hurricanes Katrina and Rita.
I expect critics of the Corps and the IPET investigation will want to dismiss this report as a whitewash of the effects of the MRGO. But they should know that the Louisiana Department of Natural Resources, often at odds with the Corps of Engineers, conducted their own model runs and came up with almost identical results.
How can this be? How can The Times-Picayune and public perception be so far off from the reality?
Well, part of the problem is simply a lack of understanding of hurricanes and hydraulics among the public. And it certainly doesn't help when newspapers and politicians jump on the bandwagon to ride public opinion for profit and populism. We all need to learn more before we form opinions on important matters.
Part of the blame falls on the Corps of Engineers, too. The Corps has not done a good job of educating their customers, the American public, about what they do and why they do it. The paper I cite is an example of this lack of communication and engagement with the public. Why haven't these findings been more prominently announced?
I think the average person can grasp why the MRGO contributes less than 8 inches to large storm surges. The simple explanation is that for events like Katrina, the storm surge is so high that water is flowing outside of the channel. When there's 18 feet of water moving toward St. Bernard and New Orleans, it just doesn't matter that there's a shipping channel down at elevation 1 or 2. The water is spread out miles wide in front of an advancing hurricane, so even the 1,000 feet wide MRGO gets lost in the massive storm surge.
Now, I'm not defending the MRGO or saying it should remain. There may well be other problems related to this channel that should be addressed.
What I am saying is that the magnitude of flooding, death and destruction was brought by Hurricane Katrina without the help of or need of assistance from the MRGO.
I think we should be talking about what to do with the MRGO. But let's stick to the facts and listen to the science.