Tuesday, September 29, 2009

Planning for the worst

The Dutch are the recognized experts in “living with water.” As a nation, the people of the Netherlands have struggled to hold back the sea for hundreds of years. Much like the people of New Orleans, they’ve suffered and prospered thanks to their proximity and intimacy with the sea.

And after multiple setbacks, New Orleans and the Netherlands both insist that humans can and should and shall continue to live and work in the low-lying coastal areas of their choosing.

But here is where we diverge: the Dutch take a holistic approach to “living with water.” Yes, they have gates and walls and levees to keep the water out of their homes, farms and cities.

But they don’t stop there.

The people of the Netherlands understand the need to plan for the worst: sea level rise, more powerful storms in the future, and protection system failures.

You get a hint of this in this recent article on the advice Dutch experts are giving to coastal California communities.

“People realize we can't just raise levees forever. If something goes wrong, you have an entire city that will be flooded in an instant. Water is a fact — we need to do something about it,” said David Van Raalten, project manager for the pilot project between the Netherlands and California and a principal in ARCADIS, an international engineering and consultancy firm.

The article notes that the Dutch have been elevating houses and setting aside land for floodplains. They’ve adopted a multi-tiered strategy that effectively multiplies their safety from flooding.

It is sad to note that New Orleans, the state of Louisiana, not even the Federal government have adopted such strategies. Quite the opposite in fact.

In New Orleans, residents defiantly demanded the “right to rebuild” in even the most flood-prone areas of the city. Local zoning and permitting rules made it all too easy to obtain a building permit to repair severely damaged houses. And the Road Home Program actually penalized homeowners who elected to move to higher ground—especially if they left the state of Louisiana.

We say we admire the Dutch. We say we want to follow their example.

But it’s obvious we don’t really mean it.


Kelly said...

Have about you run for mayor? :)

Anonymous said...

You cannot deny that many who have rebuilt in N.O. flooded areas have elevated their homes above the flood line from when the levees failed. Raised basement homes are nothing new in New Orleans.

The real problems are 1) that the Corps claims to be reliable, but repeatedly demonstrate that their designs are not sound and 2) Too many New Orleanians don't know any better than to trust the Corps claim of competency and 3) the government performed like retards with rebuilding grants holding back elevation funding until after people rebuilt as best they could afford.


Clay said...

You make some good points. As much as we'd like the levees and wetlands to be our total defense, we're always going to need backups.

I've been reading Bienville's Dilemma and I think it would be right up your alley.

Some of the points:
* Floods are acts of god; flood losses are acts of man.
* The "Levee Effect": protection leads to development right behind protection in areas that normally would have been left to nature.

The decision to allow so many slab-on-grade houses in the first place was a big mistake. Allowing so many to rebuild slab-on-grade was another big one.

In the immediate aftermath, a lot of good changes were made, like requiring IBC-level [I think that's the acronym; Tim, help me out] construction in all of Louisiana (despite howls of protest).

Anyway, I'll leave it off at that. I'll again recommend Bienville's Dilemma for you to read, though.

mominem said...

The IBC is an Insurance Company Wookie.

It does not in itself require elevation. It allows existing structures to be modified and permits "flood proof" structures. It increases the cost of new construction to levels that only rich people can afford it.

All of that in perspective, the analysis of flood elevations does not generally take into account potential failure of flood control measures.

Tim said...


I would love to be mayor. Unfortunately I don't think I could ever be elected because of this and other "radical" ideas I have. But thanks for the vote of confidence!



Tim said...


Many, as you say, are building new homes off the ground. But far many more are just fixing up their slab-on-grade houses. I don't think any permits office has done anything to truly educate the public on what that elevation certificate means and especially what it does not mean.

On your other points: (1) I do not know what makes you say the Corps "repeatedly demonstrates" poor design. Yes, wall failures in 2005 were catastrophic. Since then there has been constant improvement. (2) I agree that most people don't know enough about science and engineering to even begin to make an informed decision about whether the Corps is doing good work or not. I don't know the answer to that. The public trust was violated and it will be a long time before it can be restored. (3) I agree the rebuilding programs were poorly conceived and run. My opinion is that programs were not designed to rebuild stronger and smarter, but were intended to get as many people back to Louisiana ASAP. There was no consideration given to short-term or long-term safety or sustainability. And that's the second tragedy of Katrina.

Thanks and peace,


Tim said...

Hi Clay,

Yes, I have that book on my nightstand and I hope to read it soon.

The ICC (International Code Council) Residency Code was adopted by the City of New Orleans a few years before Katrina and is now required by state law in all coastal parishes. Codes are adapted for local use and in the case of New Orleans the requirements for impact-resistant windows and storm shutters was removed. I guess those were thought to be too expensive, although I doubt anyone has seriously considered the alternative costs. Of course as Mominem points out, the Residency Code really doesn't have much to say about flooding--it is focused on structural, mechanical and electrical safety, so when you drop the provisions to defend from wind-borne debris, you're defeating the major point of the code.



Tim said...


You note, "the analysis of flood elevations does not generally take into account potential failure of flood control measures." True, and you open a large can of worms here. We can quantify the risk of failure of a single component of protection fairly easily. But there are hundreds of components that have to work together as a system in order for the flood protection system to work. And the probability calculations required to figure that out are frankly enormous. I've seen presentations from the Dutch on the topic and they are working on the problem, too. For now I can tell you that engineers routinely design for the specified storm surge event and then step back and ask, "What happens when something larger hits us?" and "In the worst case scenario, how would this structure fail?" They then consider ways to prevent or minimize the results.

I like the ICC Residency Code and I think we have a choice to make here: cheap housing or safe housing. Safe housing costs more, but what is the alternative? Katrina was not a huge wind event for New Orleans and Jefferson Parish, but still there were tens of thousands of roof failures. Has anyone figured out the cost of that on homeowners versus the cost for better roofing? That would be just one example of how stronger codes help us in the long run.