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December 23, 2005

What's a Coypu and what does it have to do with Katrina and Rita?

I know this isn't going to fit very well into peoples desire to shift blame for what happened in New Orleans from the local government to the federal government, but I still have to point it out.

For decades upon decades a fuzzy little rodent named the Coypu has been burrowing into the levees of New Orleans. The levees offer ideal habitat for these little creature's dens and because they undermine levee systems, damage wetlands and eat crops, the state of Louisiana and her neighbors have classified the Coypu as "vermin". Locally, these rodents are referred to as nutria, and they are as common as sight in New Orleans as a squirrel is in hardwood forests. The nutria of New Orleans couldn't ask for a better habitat in which to thrive than the soft soil banks of the canal and levee system. The canals offer them room to swim and provide protection from land based predators as well as food, while the levee banks provide den space and the concrete walls atop the interior levee system ensure that human molestation is kept to a minimum.

As a youngster, I played often along the canal and levee system of New Orleans, the levees and canals defined my cohorts "territory" and I can't say how many times that rather than go to the park, I'd be down at the canals throwing rocks across the canal or running up and down the levee banks. I also can't say how many times I stuck sticks down "nutria holes" in the levee bank and scattered the little critters lounging on the canal banks into to the water as I approached.

An individual nutria will burrow a four foot diameter hole underneath the levee to make its den, they'll tunnel from 4 to 150 feet in before they carve it out. Multiply this by the thousands upon thousands of nutria living within the canal and levee system and you're left with levees that resemble swiss cheese more than they do the earthen dams they are intended to be. As I watch the investigations go forward into the levee breaches in New Orleans, I can't help but think that no one is really mentioning or considering the nutria and the damage they continually cause to the levee system. It's not like it's a secret that the nutria damage levees, the parishes and levee boards have been battling the critters for decades, but now they are mainly silent about them. I can only assume that the powers that be (mainly the media) is looking for anything they can find to blame the federal government (or man in general) and deflect attention from anything that may be considered natural causes or deficient local administration, management and animal control. I also think that because there's no direct evidence at the 17th St. and London Ave. canal breaches (hint hint: The burrows were washed away) that a policy of groupthink is setting in and people aren't seeing the forest for the trees.

I think that honest historical analysis will account for nutria undermining of the levees even if the investigations now don't consider it. I also think that building the new proposed levee system incorporating more rock and concrete, rather than just the soft dirt so loved by the nutria, will mitigate the problem of nutria undermining levees. I still don't agree with the current path the government is taking in the rebuilding of the levee system and New Orleans (I'll get to that another day), but I think that by reducing the amount of prime nutria habit along the levee banks by incorporating more concrete and rock is a good first step, just don't forget that these little critters can dig underwater folks, and given the opportunity, they will. So I hope this is taken into account.

Now I know that people will disagree with me, and that's fine, but anyone who's lived along the canals and levees of New Orleans know what the nutria do and they know how many there are. I always looked at the nutria as cute and fuzzy little buggers, but in the context of Katrina, they're evil little bastards that definately had a hand in weakening the levees and if you do the math, the nutria have removed a significant amount of soil from the interior of the levees. Hollow spaces within a levee seriously weaken the structure not to mention the erosion activity when these dens fill and drain from rainfall and pumping, storm surge and pumping, etc etc.

I'm not saying that nutria are the ONLY factor in the levee breaches, because that would be a foolish assertion, but I will suggest, and local levee boards and parrish commissions agreed with me (before the storm) that they are a significant contributing factor to levee failure and breaching. I'll also point out that the nutria (which is not a native species) are frequently cited as a MAJOR FACTOR in wetland destruction, and we all know that the South Louisiana wetlands and marshes are instrumental in sucking energy out of a storm (but we also know that blaming man for wetland destruction is much more fun than blaming an invasive little rodent eating everything in sight and digging holes in levees).

For reference I'll leave you with a few links so you can investigate and make descisions for yourself. I may return to this topic in the future, but for now, I'll just end here.

The Louisiana Department of Wildlife and Fisheries Nutria website
Wetlands Damage (from the above site)
Survey of Nutria Herbivory Damage in Louisiana
Jefferson Parrish looks at Nutria Damage to Levees mitigation
Times-Picayune article cites undiscovered "nutria holes" a factor in levee failure.

--Jason

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Posted by JasonColeman at December 23, 2005 1:00 PM