bear – ing n 1 the manner in which one comports oneself; 2 the act, power, or time of bringing forth offspring or fruit; 3 a machine part in which another part turns [a journal ~]; 4 pl comprehension of one’s position, environment, or situation; 5 the act of moving while supporting the weight of something [the ~ of the cross].
Northern Ireland blogger Slugger O’Toole says,
Newton Emerson is on great form in the Irish Times today. Since it deserves a much wider play on the Internet. I have permission from him to republish it on the net. It’s a rhetorical gem.
That it is. Regardless of what you think of the political predictions — personally, I think he’s right on — it’s a well-crafted piece of writing. Check it out, via the link above.
(h/t Instapundit, of course)
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Here’s an interesting mortality calculator. Not only does it tell you how long you’re slated to live, it tells you how much you could increase that by changing certain habits.
I’m supposed to last until mid-2063, when I’m nearly 89 years old. This is a bit less than the median (the median survival age of the general population, or of those taking the test?) I blame my parents.
Apparently I could live about eight months longer if I stopped driving, avoided all major stress (at least in the last year of my life), became a conditioning exerciser instead of just an "occasional" exerciser, and stopped having sex. Six of those months come from exercising. Apparently avoiding driving is only good for about ten days, and stress for three weeks. Sex is costing me two whole weeks of my life!
For some odd reason, the model also cheerfully informs me that if I don’t mind cutting my life short by 0.34 years, I can increase my alcohol consumption to 2-3 drinks per day. Is that good news?
h/t Clinical Cases and Images blog, via Grand Rounds.
This whole post at Instapundit is interesting: check out the many updates taken from reader e-mail.
The update from "Reader Jeff Cook" (several pages of scrolldown) is the one that prompted me to make the post, but it’s all good.
Also from the SciAm article linked in the previous post:
When Allison, the first tropical storm of the 2001 hurricane season, dumped five inches of rain a day on New Orleans for a week in June, it nearly maxed out the pumping system. [Walter] Maestri [a local emergency management director], spent his nights in a flood-proof command bunker built underground to evade storm winds; from there he dispatched police, EMTs, firefighters and National Guardsmen.
Is Mr. Maestri still around? Yep—he’s the Director of Emergency Management, and it looks like he’s been speaking to the press about the possibility of a New Orleans hurricane for several years.
Wonder if that bunker survived.
PBS interviewed John Rennie, the editor of Scientific American magazine, and got a somewhat better answer, if an obvious one.
In this case, unfortunately, what happened was that the surge of water associated with Hurricane Katrina moved through the lake, struck the levees and opened up these holes in a few places allowing the waters from the lake to then start to flow down into the city…
New Orleans has been hit by a lot of hurricanes over the years and the levees really are constructed so that they can withstand a lot of the sorts of pressures and strains associated with typical hurricanes.
The fact is that even if Katrina had really hit New Orleans dead on and if we’d seen the kind of 25-foot surge that was associated with other parts in the worst part of the storm, if that had hit New Orleans, even if the levees had held up, an enormous amount of water would have still spilled over them and flooded the city.
So really nothing is built to withstand something the strength of Katrina. But the fact is that in practice, New Orleans didn’t have to experience that extraordinary level of force. It was still enough though to break open these areas of the levees.
The interview pointed me to this article detailing how New Orleans got into this mess, and how a $14 billion marsh-restoration project might have started getting it out:
Restoring coastal Louisiana would protect the country’s seafood and shipping industries and its oil and natural-gas supply. It would also save America’s largest wetlands, a bold environmental stroke. And without action, the million people outside New Orleans would have to relocate. The other million inside the bowl would live at the bottom of a sinking crater, surrounded by ever higher walls, trapped in a terminally ill city dependent on nonstop pumping to keep it alive.
"Terminally ill" sounds about right.
This report indicates that the storm surge that hit New Orleans was larger than its classification (by wind speed) as a Category 4 storm would indicate:
Katrina weakened slightly to a Category 4 hurricane with maximum sustained winds estimated at 145 mph as it made landfall early Monday, but it maintained a storm surge that is only generally found in category 5 storms.
It’s the storm surge, not the wind, that is most relevant to the levee breaks. So the levees, which were meant to withstand a Category 3 storm, really got a Category-5-type beating.
Some numbers begin to appear:
The lake, which normally is 1 foot above sea level, peaked at 8.6 feet above sea level, said English.
How tall are the levees?
Want to be a finger-pointing talking head?
Rick Moran has assembled the definitive, authoritative Katrina timeline. It’s a prerequisite.
For extra points, read it in conjunction with Brendan Loy’s real-time weatherblogging.
"Levees fail. People need to realize when they make a decision to live
behind levees that there’s a risk that comes with that,” said Jason Fanselau
of the U.S. Army Corps of Engineers’ Sacramento office. "They can fail on warm
sunny days like we saw last year with Jones Tract (San Joaquin County), and
they can fail with huge wet storms like this week” along the Gulf of Mexico.
This part doesn’t sound right:
The Category 4 Hurricane Katrina caused two levee collapses — a
300-foot breach in the 17th Street Canal flood wall and a smaller break in the
Industrial Canal flood wall — when water overtopped the floodwalls.
I don’t see how water overtopping the floodwalls necessarily causes the collapse—that would have been an entirely different problem. Or is the top of the "floodwall" not synonymous with the top of the levee?
Here’s someone at Daily Kos who blames vortices that erode the levee from the bottom:
<>
Water always moves. When it comes up against an earthen barrier its
movement shifts from straight on or alongside the levee and is
transformed into a swirling motion. Any variation in the levee — a
dip, a swerve, a slight indentation — catches the swirling currents
far below the top of the levee itself. The water swirls down there like
a giant very efficient drill, weakening the levee from within. When it
goes, it can do so quite suddenly; it "blows" a hole in itself and thus
the name "blew holes," sometimes called "scour holes."
<>
Water only moves—the term he really wants is "flows" — when it’s not at mechanical equilibrium. And the direction it’s flowing matters. Did the water alongside each levee, in fact, have a net velocity that created—not just vortices—but vortices that were unanticipated by the designers digging away at the base of the levee?
Erosion could be one cause. What others are there?
A brief search for levee failure in the Science Citation Index turned up a number of references to levee failure. Most of the ones I saw had to do with two mechanisms of failure (not counting overtopped levees—only broken ones.)
The first is percolation of water through porous layers of material in the levee, apparently referred to by some geotechnical engineers and others as "piping:"
A phenomenon called "piping" sometimes occurs under levees and may be accompanied by the formation of sand boils at locations where seepage surfaces. Starting from the point of sand boil formation, a pipelike opening develops below the levee base … and proceeds toward the stream. If this process continues, the failure of the levee becomes inevitable. Permeability is a key component of piping models in defining the critical head limits needed for the safety of levees. (C. S. P. Ojha et al., "Influence of Porosity on Piping Models of Levee Failure," J. Geotech. and Geoenvir. Engrg., Volume 127, Issue 12, pp. 1071-1074, December 2001, not available online to the general public.)
"Head limits" are pressure limits. A direct proxy for pressure is the water level above the base of the levee. A levee can fail to do its job "because the water got too high" for two reasons: (1) the water spilled over the top of the levee, or (2) the water pressure difference across the base of the levee grew to exceed the threshold at which water can percolate through the levee material.
A combination of erosion and seepage seems to have been the main mechanism of structural failure during the Mississippi River flood of 1993:
Levee failures within the study reach occurred primarily as a result of overtopping linked with wave-induced surface erosion rather than structural failure, but a number of saturation-induced mass failures were precipitated by the high flood stages… In particular, side-slope seepage and underseepage were recurrent problems along the Sny Island levees, and were probably responsible for its eventual failure. (Gomez et al., "Floodplain sedimentation and sensitivity," Earth Surface Processes and Landforms, 22 (923-936), 1997, not generally available online.)
Scouring is mentioned, too.
The other mechanism of failure that seems to be mentioned, but mostly by mathematicians, is hydraulic shock waves. Is that even plausible?
The follow-up story that I am most interested in seeing, even though I doubt it will get much national media, is the engineering analysis of the New Orleans levee failure:
That’s just a start, from someone whose training is in chemical engineering, not civil or mechanical engineering. Somewhere, someone who knows how to answer these questions is asking them, I hope, and asking others that I don’t know enough to ask.
There will be plenty of highly visible people, in the next days, weeks, and months, asking the question Why did the levees fail? But the vast majority will be seeking political answers. Their question is really why didn’t somebody spend more money on the levees? As if wads of cash, dropped from helicopters, could plug up the hole; as if stacks of coins could resist pressure fluctuations that earthen berms could not.
Here’s an example from August 31, in Editor and Publisher:
…[W]ith the 2004 hurricane season starting, the Corps’ project manager Al Naomi went before a local agency, the East Jefferson Levee Authority, and essentially begged for $2 million for urgent work that Washington was now unable to pay for. From the June 18, 2004 Times-Picayune:
"The system is in great shape, but the levees are sinking. Everything is sinking, and if we don’t get the money fast enough to raise them, then we can’t stay ahead of the settlement," he said. "The problem that we have isn’t that the levee is low, but that the federal funds have dried up so that we can’t raise them."
Obviously, fixing stuff costs money. But to say that the problem you have isn’t the physical problem is to live in an abstract political world where the solution to every problem is to throw money at it and hope it sticks. Projects can be lavishly funded and yet poorly engineered.
Contrast that article with this one, after a levee break in 1997, which details the kind of thinking I am looking forward to seeing:
Meehan said the doomed levee [in the 1997 failure—E.] was "generally similar" to two nearby levees that failed in previous disasters – the Christmas Eve 1955 levee break on Shanghai Bend south of Yuba City that killed 38 people, and a break near the Yuba County town of Linda in 1986 that produced $500 million in damage claims.
Both of those levees failed, Meehan contended, because flood water had saturated a subsurface layer of gravel, then flowed underground far to the landward side of the levees and erupted, geyser-like, undermining the structures and causing their collapse.
The engineer quoted in that article doesn’t say a word about funding. Instead he testifies about pressure relief wells, underground migration of flood water, subsurface gravel layers, and premonitory sand boils.
Let’s hear some more talk like that.
In one very real sense, funding is no more than another engineering constraint. The pylons can be no wider than this, or the largest barge cannot pass under the bridge. The floating roof of the storage tank can be allowed to fluctuate no more than this, or the emissions will exceed federal standards. The materials can cost no more than this, or the project will run out of money.
The only engineering difference between the properties of money and the properties of stuff like, oh, I don’t know, the shear strength of concrete, or the percolation rate of water through gravel, is the persistent, mesmerizing illusion that the supply of money is theoretically infinite. Running out? You can always get more from somewhere. Raise taxes! Divert it from somebody else’s project! Full speed ahead!
It may very well be true that lack of funds was a prime cause, if a remote cause, of the New Orleans levee failure. If so, then it will be legitimate to ask whose decisions failed to provide the necessary funds.
But neither question can be answered until we understand the proximate cause for the breach in the levees. Not just one, but three levees, simultaneously. By "the proximate cause" I mean "the cause of pieces falling off of them in this particular spot at this particular moment."
"Lack of funding" doesn’t explain why the levees failed here instead of there, as if someone laid the cash on with a trowel and missed a spot at 17th street.
"Lack of funding" doesn’t explain why the levees failed on Tuesday instead of Saturday.
"Lack of funding" doesn’t even explain why the drearily predictable scenario, New Orleans underwater, occurred after a levee failure instead of after a levee flood, in some other, stronger hurricane, some other day in the future.
But if we figure out why the levees failed here instead of there, if we figure out why the levee failed sooner instead of later, if we figure out why the levees failed in this storm instead of holding in this storm, then we can begin to understand the degree to which more money could have made a difference; then we can begin to understand the degree to which competent foresight could have predicted that need; then we can begin to understand the degree to which the political climate enabled decisionmakers to advocate for that need in the timespans of their offices.
We might even be able to answer the question of whether the levees were competently designed and competently built at all—that is, whether the levees were up to the standards you should expect even given the particular funding constraint. In other words, did we get our money’s worth?
Henry Petroski, where are you?
If you haven’t read Brendan Loy’s archives, you should, moving upward from this starting point, posted at quarter to 2 pm on Tuesday, August 23:
T.D. 12
Just a few hours after Tropical Depression Jose was declared dead over Mexico, Tropical Depression 12 formed over the southwestern Bahamas. It could become Tropical Storm Katrina.
UPDATE: Hurricane Katrina? It could happen…
Brendan Loy is a 2L law student at the University of Notre Dame. Most of his posts are about school, about his fiancee, about politics. He is also a weather enthusiast.
Starting at the post linked above and scrolling upwards, you watch as his other interests fall away and he begins full-time Katrina-blogging, linking all the while to radar maps, official forecasts, and articles from past years that gloomily predict the New Orleans doomsday scenario that has now come to pass.
Eventually he begins to plead with residents to get out of town.
Just before 7 pm on Saturday, August 27:
Hurricane watches, as expected, have been extended eastward to the Alabama/Florida border, but that doesn’t indicate a rightward lurch in the track; the NHC simply put the Louisiana warnings up early, to give New Orleans and vicinity more time to prepare. The track has actually edged ever-so-slightly to the left, but the below-sea-level city of New Orleans is still directly in the crosshairs.
For some reason that I can’t even begin to comprehend, the evacuation order for New Orleans is only "voluntary" at this time. The mayor says he might issue mandatory evacuations tomorrow morning, depending on what the forecast says. What is he waiting for??? The forecast calls for a DIRECT HIT! This is the story we’ve been fearing for decades! And if he waits until 24 hours before landfall to order people to leave, it may very well be too late!
In the next post, entitled "The mayor of New Orleans is an idiot," Brendan writes,
I can’t emphasize enough what a bad decision I think it is for New Orleans Mayor Ray Nagin to delay the mandatory evacuation order until tomorrow morning. According to the Weather Channel, lots of tourists in the French Quarter are happy the evacuation is only "voluntary," and are planning to stay in town until it becomes mandatory…
Will Ray Nagin go down in history as the mayor who fiddled while New Orleans drowned? Could be.
Read it.
Do you have a family disaster plan, one that is appropriate to the kinds of disasters most likely to befall your area?
We don’t—yet. But we will, before winter falls on Minnesota this year.
And one thing is certain: No part of it will depend on actions, or even on suggestions, by local, state, and federal government.
There will be no algorithm that says, "Do such and such if the mayor orders an evacuation," or "Do this and that if the governor orders a state of emergency."
There will be no part of it that assumes that anyone, anyone at all, will come to our rescue.
We rely on the government (any level of government) to save us only at our own peril.
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