Sunday, October 02, 2005
On the Levees of New Orleans, Book II
The Apple Eats Cajuns for Breakfast
People return to New Orleans:
...Local officials and residents remain fearful that efforts by the U.S. Army Corps of Engineers to shore up the levees and flood walls that hold back Lake Pontchartrain and the Mississippi River will fall short if another storm hits the city.
In the swampy wetlands of Houma to the west of New Orleans, 2,000 people rallied Thursday evening to demand U.S. government funds to build levees that could withstand the most powerful Category 5 hurricanes...
"Interim is just not good enough," New Orleans city councilman Jacquelyn Clarkson said after engineers briefed city officials on plans to bolster levee defenses this week...
Meanwhile, the corps has quietly been withdrawing its early conclusions about why the levees failed.
Within days of the flooding, federal engineers asserted that the flood-control system was simply never designed for such a powerful storm.
Now, with evidence suggesting Katrina's intensity fell within the range the levees should have handled, corps spokesmen are saying the organization wants to conduct a full-scale analysis of the design and construction of the levees...
One of the fundamental theories is that the sheer power of the storm surges in the channels hammered the levees and shoved over the estimated 60 feet of concrete and steel floodwall partially embedded in each earth levee.
Another theory holds that storm surge water flowed over the floodwall, cascaded down the other side and scoured the base of the levee, causing the wall to fall. The third is that downward pressure forced a column of water through the floor of the canals and the water came up on the other side. The water then loosened base material from the levees and their embedded steel "sheet piles," causing the floodwalls to topple...
Vincent A. Ettari, a licensed P.E. in Westchester County, New York, provides his assessment, reprinted here in its entirety from the NOLA.com forum where he originally posted it yesterday:
I am a Licensed Professional Engineer who has designed waterfront structures and works along the Hudson River. I also designed a dam for Damon Pond. I worked for several years for the New York City Department of Environmental Protection.Due to the fact that the collapses of the levees and walls in New Orleans were occurring after the peak storm event had occurred, I alerted FEMA that, in my opinion, the levees were compromised and that the city should not be reoccupied. I sent an e-mail to this effect to FEMA on September 11th. FEMA responded to me via e-mail on September 15th. However, I did not start seeing any public acknowledgements that the levee system was compromised until September 17th. As a result, people needlessly repopulated the city, only to have to leave it again with the onslaught of Hurricane Rita.
I have examined the data presented in the various articles which have appeared concerning the levees. There is now a wide divergence of opinion between those who are modeling Hurricane Katrina and the Army Corps of Engineers. The modelers claim that the levees were never overtopped while the Army Corps claims that the levees were overtopped and that they could have withstood a Category III Storm.
However, from a structural engineering point of view, the levees and flood walls appear to have been grossly misdesigned for the containment of waters which only reached to the top of the flood walls. Here are several reasons for that assessment.
1) First, the earthen levees are composed of fill. Retainage structures, such as the flood walls which failed, can exert forces at their toes of many, many thousands of pounds per square foot (psf). There is simply no way that fill can be compacted to such an extent that it can support this amount of toe pressure. That retainage systems can exert these types of pressures on the soils beneath their toes has been known for over a hundred years. Therefore, the setting of the flood walls on the earthen levees was a design error.
2) Second, we now know that the flood walls were partially supported by sheetpiling which went through the dirt levees. However, the dirt levees are set on self-compressing soils deposited over thousands upon thousands of years by the river. Piles, even sheetpiles, set in fill and self-compressing river silts and muds are subject to down-drag as the material consolidates and settles. Down-drag on the sheetpiles, with the accompanying downward movement of the sheetpiles and the concrete flood walls which they supported, would cause the walls to differentially move. This, in turn, would cause the concrete of the walls to crack and tear apart. Therefore, the walls suffer from this design error.
3) While it is true that retainage structures can be supported by piles if those piles extend down to bedrock, a special type of pile called a "Batter Pile" must be used to convey the toe pressures down to the deeper, stronger rock layers. The use of sheetpiles as a support for a retainage structure does not conform to standard engineering practice for the design of retainage walls.
4) We now also know that the vertical slabs of the concrete walls were not "interlocked". Actually, we now know that the separate pours of the flood walls were separated by rubber gaskets. Such expansion joints are never used in structures which serve as dams. They allow differential movements between the vertical slabs of the walls which ultimately tear the rubber gaskets and compromise the retainage system. Since the walls would, by design, serve as temporary dams during storm conditions, they should have been designed to act like dams (and not like foundation walls). Therefore, the walls suffer from this fourth design error.
5) Based on the photographs I have observed, the walls look to be about 12 inches thick and have little to no batter. Depending on the placement of the steel, the compression on the Compressive Stress Block would be as high as 7600 psi (1 Inch Thick Stress Block assumed in the absence of detailed plans for the placement of the steel re-bars) for a seven foot high wall of water and as high as 29,530 psi for an eleven foot high wall (once again: 1 Inch Thick Stress Block Assumed in the absence of more data), using the 1.6 Factor of Safety prescribed by ACI and no strength reduction factors (1.7 was prescribed at the time the walls were constructed). While 5,000 and 10,000 psi concrete is normally used in the construction of a dam, it is likely that standard 3000 psi concrete was used in the construction of these walls. Either way, these compressive forces are greater than the allowable forces for even 10,000 psi concrete. Therefore, the stems of the walls appear to be too narrow (these calculations are subject to more detailed analysis once the placement positions of the vertical bars are known).
These design errors are obvious errors which should never have been made.
Among his other qualifications, Mr. Ettari has four years work experience at the New York City Bureau of Water Supply. The story of this institution is legendary:
In the mid-nineteenth century, New York City was the most important city in the United States, yet it lacked a clean, reliable, and disease-free water supply. New York's solution was to create a water supply board with the mission of delivering clean water directly into Manhattan. This organization was staffed by professional engineers, not political hacks, yet it was endowed with absolute power: throughout the City the Board could seize private property as needed and Upstate it could control the plantings of farmers near every stream that fed into the Hudson River watershed.
These engineers used their power responsibly. The results of their labors include Central Park, its reservoir, and the finest big-city water supply on the planet, one so clean that it doesn't need chlorination and regularly wins awards for its fine taste. The Bureau of Water Supply still has a reputation for strict engineering and is supervised by the New York Public Service Commission, one of the finest regulators I know of: a telephone call late on a Friday afternoon regarding water supply problems can trigger an avalanche of overtime activity and a permanent fix by Sunday morning. (A more conventional history of the NYC water supply is provided here.)
The contrast between the New York City Bureau of Water Supply and the Orleans Levee Board could not be greater.
Outrage, Analysis, and Nail-Biting Anticipation
A sense of outrage and disbelief is growing among Jefferson Parish residents at the decision by Parish President Aaron Broussard’s administration to evacuate drainage pump operators...
“This wasn’t an act of God. It was an act of stupidity..."
Administration officials say they are still analyzing data on the hurricane and its effects, and that the full implications of the decision to evacuate pump operators won’t be known for some time.
As discussed previously, maybe evacuating the pump operators was the right thing to do.
On September 29th, G.B. emailed me his in-depth engineering analysis of pumping effects upon levels of the 17th Street Canal:
You have essentially two equations with two unknowns, water depth and velocity (Reference: LMNO Engineering):
Continuity Equation, V = Q/A
Manning Equation, V = (1.49/n) * (R^(2/3)) * (s^(1/2)), where:
Discharge, Q = 9380 ft3 / sec
Water Depth, y = variable
Canal Width, b = 200 ft
Area, A = y * b
Wetted Perimeter, P = 2 * y + b
Hydraulic Radius, R = A/P
Mannning Value, n = 0.030
Slope = 0.00014
(Using the Corps levee map which shows the floodwall heights above NGVD increase from 13.5 ft at the outlet to 15 ft at the pump station and a canal length of ~ 2 miles and assuming the relative floodwall height remains constant would give a canal slope of approximately 0.75 ft / mile = 0.00014)
Using Excel, I calculated the velocity using both equations for various water depths, y, and made a plot of Velocity vs. Water Depth. The point at which the two lines cross [the solution of Q/A = (1.49/n) * (R^(2/3)) * (S^0.5)] is the steady state flow water depth.
Using the Solver function gives a water depth of 14.6 ft. for the above inputs (essentially the original input value you gave The Ruminator for his initial calculations). Note that this is the uniform water depth along the entire length of the canal. Using the width to depth ratio of 25:1, during a calm sunny day (lake and canal in equilibrium) the water depth in the canal would be about 8 feet (~ 1 ft NGVD since the lake level is about 1 ft above sea level). At pumping station capacity the water depth in the canal would have to be 14.6 ft (~7.6 ft NGVD) to achieve steady state flow. If you were to read this on a gage taped to the floodwall the water level would come to about 6 feet from the top of the wall. [One thing I forgot to note in my original e-mail is that according to the Corps levee maps, the floodwall on the Jefferson Parish side of the 17th Street Canal is about 6 inches higher than on the New Orleans side. Interesting, huh?]
At the bridge what I conceptualized was based more on years of experience flood irrigating hay fields than any structured engineering analysis, in which the analogy goes something like this: Open the headgate to start a specified amount of water flowing down the ditch. The water reaches an obstruction or restriction such as a sluice gate or tarp dam. The water begins to back up in the ditch until it reaches the level of the cut in the ditch wall closest to the dam. The water continues to backup until the dam overflows or the amount of water flowing out of the cuts in the ditch equals the flow from the headgate, allowing a controlled amount of water to flood the desired amount of acreage. One thing that can often happen though if you’re in a hurry and open the headgate a little too much is that as the flowing water hits the dam or sluice gate it “sloshes” back, overflows the side of the ditch near the dam, finds a weakness such as a loose dirt clod or hoof print and you get a blowout, ala floodwall failure. In this example all it takes is for one floodwall section to be an inch or two lower than the adjacent section for overtopping to occur. Note the step height change in this photo. I don’t know if there was similar step changes in the vicinity of the breach, but in the bridge photo, you can definitely see a support column on the north end of the breach.
In short, pumping may have caused water to "pile up" upstream of the bridge until the Canal overtopped. G.B. continues:
I don’t think the extent of the breach is due to something being wrong with the levee’s design or construction per se. Any expanse of concrete like this is going to require gaps to account for thermal and moisture expansion and contraction. Otherwise, it’s likely to experience fractures in undesired locations. The shear strength rests entirely in the sheet piling and rigidity of the concrete wall. The shear stress/separation failure could have been mitigated by using sheet piling with the interlocking design pictured with the hot-rolled Z-section piling in the Corps manual (I’m sure at a significant cost increase) or by anchoring the top of concrete wall sections together to prevent shear separation.
On the other hand, I don’t think the Corps design took into account the possibility of overtopping occurring on a limited length of floodwall as in the “streamflow model”, in which interlocking wall sections could reinforce each other and possibly prevent the separation and failure of just one or two sections. Since the levees serve as hurricane protection, it’s entirely reasonable to use the storm surge model of extensive overtopping in the floodwalls’ design considerations. In this more likely event, anchoring wall sections together could result in a truly catastrophic levee failure in which the loss of sufficient lee side soil strength at one section causes that section to fail which pulls down an adjacent weakened section, which pulls the next section, which pulls the next section...resulting in a breach of several hundred yards not just feet.
So linking the concrete floodwalls may just have made matters even worse!
About 25 years ago, Gus Cantrell built a small plywood clubhouse...abutting the London Avenue drainage canal...when Cantrell returned last week he found everything -- except the clubhouse -- massively damaged...[it]stood exactly where it did before the storm, with one change. The ground on which it sat, still green and grassy, was thrust about 8 feet straight up in the air...
Cantrell, an engineer who worked at the University of New Orleans until his retirement, believes the anomaly reflects a design flaw -- a slope stability failure in the soil holding the flood walls along the canal bank, that collapsed and heaved up the earth under the clubhouse -- and not, as the Army Corps of Engineers has argued, water coming over the top of the floodwalls.
And that conclusion gives him pause about the Corps' central role in rebuilding the failed system it designed to protect New Orleans.
"I'm afraid the Corps is going to try to build that levee back to the same configuration it was, and that would be a terrible mistake," Cantrell said last week. "There should be an honest investigation."
Corps engineers and separate teams from the American Society of Civil Engineers, the University of California, Berkeley, and Louisiana State University spent several days gathering data at the sites of failures in the London Avenue and 17th Street drainage canals and the Industrial Canal navigation channel that conspired to destroy most of the city. They are scheduled to provide the first status report on their work today.
The Corps insists that despite its early insistence that the Category 4 storm surge from Katrina drove waters over the top of levees designed only for Category 3 storms, it is approaching the rebuilding task with an open mind, and parallel analysis from outside groups will help ensure a right answer...
I'm chewing my nails right now! We'll look at their report in the next Update.
Update 2: 10/9/05
Floodwall Overtopping May Not Be to Blame
The teams investigating the floodwall failures say that a thin band of soft, peatlike soil lay more than 20 feet below the walls at both the 17th Street and London Avenue canals. But because the layer was deep and narrow, the crews that initially built the walls did not discover it, the engineers said.
Then why didn't the Orleans Canal fail as well?
Engineers Offer a New Explanation of How Levees Broke
Professor Bea suggested that the Corps might well have missed soil problems in its core samples, since the soil appeared to vary in quality. "You can't take borings every inch," he said.
If the Corps had determined that the soil was weak, it could have driven the sheet pilings that form the spine of each levee farther into the ground than the standard 30 feet in order to prevent shifting, Professor Bea said. "That would be No. 1 on the list," he said.
As the last Update implied, the ASCE Team Statement blamed soil failure, a subject Solomon2 knows very little about. I note, however, that of the members of the ASCE investigating team one fellow who caught my eye was Francesco Silva-Tulla, who literally wrote the book on earth slope stability analysis. This aspect of the investigation thus appears to be in good hands.
There is a lesson here: to a hammer every problem looks like a nail. My engineering and science background did not include soil mechanics, so I speculated that the floodwall failures had other causes. These may still apply, but they may make as much difference to the floodwall failures as a six-knot wind does to a motoring yacht: very little.
Therefore, the integrity of the investigation is what I plan to concentrate on in future posts, though I may continue to include material offerred to me by other engineers.
Update 3: 10/16/05
Think, and Full Steam Ahead!
Engineers Examine Levee Failures:
The central issue they grappled with: Did Katrina overwhelm the city's flood defenses with a torrent they weren't designed to contain? Or did faulty construction or maintenance cause them to burst open at water levels well within their capacity?
Maybe the Army should call in the Dutch? Consider:
"At this time, we haven't fully understood the failure mechanisms at all of these locations," said Walter Baumy, chief of the engineering division of the corps' New Orleans district.
If investigators find that design flaws caused the failures of New Orleans canal floodwalls during Hurricane Katrina, fixing the problem could delay the restoration of the levee system to its pre-storm strength, pushing work into the next hurricane season, Army Corps of Engineers chief Carl Strock said Thursday.
They'll be hard at work quite soon:
Within weeks, the Army hopes to have dozens of contracts issued for the work, mobilizing teams of local and national contractors. The job will require moving 3 million cubic yards of dirt, enough to build a mound 1,575 feet high covering an entire football field.
If successful, the crash program will restore a measure of hurricane protection to the region, but will still fall short of the defense needed against storms as big as or bigger than Katrina.
The Ruminator offers his opinions here.
Update 4: 10/21/05
Pelf, Progress, Probes, & Criticism of the Bush Administration
The President of the Orleans Levee Board, Jim Huey, awakens from his slumber only -
to steer two no-bid, post-Hurricane Katrina contracts to relatives and to collect nearly $100,000 in back pay for himself...Huey said he was forced to move quickly on the salvage contract because the recovery of boats by insurance companies and owners was threatening to devolve into chaos along the Lakefront...
O.K., it seems the Levee Board was helping the Port of New Orleans resume operations. But you can't blame the public and the press for spinning the story this way, after what happened to the city.
The Corps Is Fortifying Its Levee Repairs -
after investigators questioned how well the emergency patches made after Hurricane Katrina would hold.
Investigators for the National Science Foundation sent an eight-page critique of the corps' work early this month, saying that some of the repairs lacked adequate strength and were actually leaking water through materials used to plug breaches.
...Separately, it was announced Wednesday that the National Research Council would begin yet another investigation into the levee failures, the fourth such probe since the flooding of New Orleans that claimed hundreds of lives.
The corps asked for the new investigation, which apparently stops well short of calls for the White House to appoint an independent board empowered to conduct a full-scale technical investigation and issue formal recommendations.
Kudos to Ralph Vartabedian of the LA Times for the quality and perseverance of his reporting.
Yesterday, the AP reported Rumsfeld Orders Independent Levee Probe:
In recent weeks, the government has come under criticism for allowing the Army Corps of Engineers to be in charge of investigating its own work.
Rumsfeld directed Army Secretary Francis J. Harvey to form a panel of engineering and atmospheric experts under the direction of the National Academy of Sciences, the Pentagon said in a statement Wednesday.
Occasionally, I examine my visitor statistics. From these I deduced that Rumsfeld quietly ordered a second probe several weeks ago. I thought it best not to mention this until the second probe became public knowledge.
Over a month ago, I wrote that the Department of Homeland Security's story that they didn't know about the levee breaks until the day after they happened was scarcely believable, and I speculated that instead the DHS simply didn't UNDERSTAND what was going on. Now the stories start to pop out:
As recently as this week, Chertoff told a House Katrina investigation, "The report -- last report I got on Monday [Aug. 29] was that the levees -- there had not been a significant breach in the levees. It appeared that the worst was over."
In contrast...[a]bout 7 p.m. Aug. 29, Bahamonde said, he called Brown and warned him of "massive flooding," that 20,000 people were short of food and water at the Superdome and that thousands of people were standing on roofs or balconies seeking rescue.
Brown replied only: "Thank you. I'm going to call the White House," Bahamonde said.
19 pages of internal FEMA (search) e-mails show Bahamonde gave regular updates to people in contact with Brown as early as Aug. 28, the day before Katrina made landfall.
One or two Democratic DC insiders tell me that FEMA was a good agency under the previous Administration: Hurricane Andrew in 1992 had left a deep impression so Clinton reorganized the Agency for quick and efficient response, yet even before 9-11 Bush had begun to dismantle FEMA. The creation of DHS, by "streamlining" - that is, suspending - fair workplace rules only made matters worse: In a dispute, it isn't you against your boss anymore, but you against the government.
Perhaps these tales should now be given some credence, and in this respect the Bush Administration is to blame.
Update 5: 10/24/05
The S--t Hits the Fan
MSM outrage over the levee failures is now sharply refocusing upon design faults, although I don't think construction flaws can be ruled out yet. John McQuaid (Newhouse) published an story pointing out that engineers knew about the weak soil layer beneath when the 17th Street Canal was originally designed. The New York Times points out that the steel pilings may not have been driven deep enough.
I think the best MSM article yet is in today's Washington Post. Michael Grunwald of The Washington Post has been covering the levee failures for weeks. Keep in mind, however, that he is assisted by "designer David Murray", so naturally such reporting is colored by the design point-of-view:
...all three breaches are looking less like acts of God and more like failures of engineering that could have been anticipated and very likely prevented...The new findings for the first time point to a human role in all three of the major floodwall failures...
Captain Ed already has a good commentary posted at his blog. But the The Times-Picayune has a very interesting story today discussing not only the failures but also how the flood-history author of "Rising Tide", John Barry, has been invited to walk alongside the official investigators. Good going, Mr. Barry, and we look forward to your next book!
The Engineering News-Record provides details of the new panel sought by Defense Secretary Rumsfeld:
National Academies of Science and Engineering to assemble a panel from a variety of disciplines to study whether levee or floodwall failures occurred because of design, construction, operation or maintenance factors, soil conditions, "changed assumptions" on which design or construction was based, or the strength of the hurricane.
Assistant Army Secretary for Civil Works John Paul Woodley Jr. told a House water resources and environment subcommittee hearing on Oct. 20 that the National Academies review is expected to take about eight months...
The National Academies' panel is to issue findings and make recommendations based mainly but not exclusively on these other investigations, DOD said.
This new panel is essentially the same as the Advisory Committee on Levee Safety I proposed creating last month. Its scope shouldn't be limited to New Orleans because there is concern that inadequate flood defense may be a nation-wide problem:
As people and critical industries have concentrated themselves in the most exposed environments on the North American continent, the nation’s resolve to protect them through environmental measures or public works has lagged...
Over the last 30 years, people and industry have migrated to hurricane country, lulled into what now appears to be a false sense of security fed by a period of reduced storm activity. And people continue to come. By 2025, the U.S. Census Bureau estimates that the population of the five Gulf Coast states will increase 72%, from 44.2 million people to over 61 million. Scientists now agree that another cyclic uptick has begun that will spawn more and greater storms...
I suppose the new panel will become a permanent yet necessary cog in the machinery of government.
Update 6: 10/27/05
The 17th Street Canal floodwalls are not being rebuilt as they existed pre-Katrina. The Engineering News-Record reports:
Local firm Boh Bros. Construction Co. LLC, New Orleans, won the latest construction contract, for $6.2 million. Boh will install sheet piling where the 17th Street Canal floodwall breached. Unlike the original 17-ft-deep sheet piling, topped with poured-in-place concrete floodwalls, the new piles will be driven to 50 ft depths and will be placed on the canal side of the existing wall.
The sheet piles "will provide an interim level of protection and will become the cofferdam for the reconstruction," says Dooley. "The reason they are driving that deep is that when that wall gave way it sucked a 25 to 30-ft-deep hole in the ground and created scour along the alignment in both directions."
...Plans also call for replacing the "I-wall" design of the old flood walls in the repaired areas with an inverted "T-wall" configuration. Dooley says the adoption of the design change does not signify that the Corps has concluded I-walls were insufficient. Rather, it is being adopted to apply a "more conservative design" in the damaged areas, he says. "We are putting a wall over a hole," he says. Unlike the I-wall, which was founded and fastened to the top of the sheet piles, the T-walls will be supported by their own dedicated piling system.
A "more conservative design" - so even non-specialist engineers like me can appreciate it, thank you. Will they also add an impermeable liner to the Canal as well? Does it really need to remain navigable?
[Corps of Engineers spokesman Alan] Dooley says repairing defenses is already authorized but re-engineering the system is not, so the Corps has no plans for enhancing the city’s defenses. He says he expects any issues raised by the investigators needing significant redesign will be addressed.
Reads like a "significant redesign" to me. ("Why didn't they set the pilings that deep the first time around, when they built these?" said Ivor van Heerden.) I suppose the Corps is stretching definitions a bit, but their current mandate is to build a Category 3 defense (though a Category 5 has just been drafted), however
specialists now believe Katrina was no stronger than a Category 3 storm when it roared into New Orleans, and Congress had directed the Corps to protect the city from just such a hurricane.
"This was not the Big One -- not even close..."
The changes reported by ENR are a de facto admission of the inadequacies of the previous design -- though the Corps hasn't quite admitted that yet:
Army Corps of Engineers officials and the contractors that designed and built the wall were aware of the soft soil and took it into account in design calculations, the documents show. That only deepens the mystery about whether the wall breached due to some design or construction flaw, some factor unaccounted for in the calculations, or was hit by forces beyond its design capabilities.
"According to the (design) analysis, they've got the soil strength test. It doesn't show exactly the input for the analysis, but assuming they used it and came out with factors of safety, it's showing the numbers are safe. So it leaves an open-ended question..."
...Engineers studying the levees also say that other, thus far unknown factors including structural problems in the walls could also have contributed to the breaches...
I suppose the "unprecedented" COE-ASCE-NSF investigation may serve to rule out such unknowns, so professionals and the public can have greater confidence in their failure analyses. Investigators should get on with their work and not get too absorbed in the sort of bickering reported by PBS:
"...just one week into the probe into why the levees broke a more immediate problem emerged. One of the corps's own independent investigators wrote a blistering letter to the corps, critical of the levee repair work in New Orleans.
Dr. Raymond Seed, a world famous civil engineer who heads a team of investigators for the University of California at Berkeley, wrote that the corps' work at the 17th Street Canal breach "did not appear to have improved the situation, indeed," he said, "it had likely made it more dangerous."
Seed cited the row of big sand bags placed "like flower pots" on top of the damaged levee, saying they "did not block the likely points of water ingress." Dr. Seed said open stone also placed on top would not be "effective in mitigating erosion of the underlying embankment." And he wrote "dauntingly similar apparent shortcomings" exist at the other four breach sites which flooded massive sections of the city.
The American Society of Civil Engineers voiced similar concerns about the 17th Street Canal, saying, "stability in the repaired areas may be deteriorating."
It has already been guessed that reconstruction alone may be insufficient, so the PBS story, although of interest, is slanted towards stirring up the cauldron unnecessarily.
I strongly suggest employing some public relations specialists to buffer the engineers and investigators from this type of turbulence, or else members of the investigating panel may spend inordinate amounts of time dealing with ignorance and confusion spread or inspired by the media. (I witnessed this phenomenon at Nuclear Regulatory Commission Headquarters in the 1980s.)
Update 7: 10/28/05
This is the sort of instant analysis investigators should now avoid:
Conditions suspected of causing the 17th Street Canal levee wall failure that flooded much of New Orleans should have been obvious to the engineers who designed the structure, a team of LSU researchers said after viewing documents obtained by The Times-Picayune...
...[team member Radhey Sharma]: "This could never work."
This is not the time to squash people down. Sure, some people probably made mistakes. But I doubt that the full story can come out in an atmosphere of hostility.
Am I, one of the first critics of the situation, suddenly changing course? Not really. Two months ago I felt it reasonable to assume that New Orleans could be dangerously exposed to another hurricane, so some changes had to be made very quickly. And that happened, yes, but the city is not now in immediate danger.
What professional prestige can be gained by those who had no responsibility denouncing those that did, all based on a few possibly out-of-context records, before they have a grasp of the project history?
Obviously, that implies the Corps should open its records for review as soon as they can be retrieved.
Of course, the Times-Picayune may be giving a mistaken impression of the dynamics of the investigation, or maybe the T-P's info is more extensive than I know of. All the more reason, then, for an effort to be made at improved public relations.
Leaders of the investigation could also make efforts to smooth a few of their own feathers as well.
Update 8: 10/30/05
Not a dog, not a cat, not a goldfish: it's IPET!
That's the acronym of the team investigating the New Orleans levee/floodwall failures. Courtesy of U.S. Newswire:
The U.S. Army Corps of Engineers on Oct. 29 will begin publicly releasing available data relevant to the performance of the hurricane and storm protection system around New Orleans during Hurricane Katrina.
The current releasable data will be posted on a publicly accessible web site, https://ipet.wes.army.mil . Additional data will be added to the web site as it becomes available.
Because the Corps of Engineers wants to find out what happened from an engineering perspective to the New Orleans protection system to ensure optimum designs for its reconstruction and for future projects, the Chief of Engineers commissioned an Interagency Performance Evaluation Task Force (IPET) to perform the engineering evaluation. The American Society of Civil Engineers (ASCE) is supporting with an External Review Panel, which will provide an independent oversight of the IPET evaluation.
The IPET is gathering data and will perform the analysis. All other groups, including the National Science Foundation (NSF) (comprised of the University of California - Berkeley), are working to learn what they can about the levee system and what can be applied to levee systems in California and elsewhere.
The data released will include design memorandums, dating back to the 1960s, and the associated reports for the Lake Pontchartrain, Louisiana and Vicinity High Level Plan, which includes 17th Street Outfall Canal and London Avenue Outfall Canal.
This information being released includes the project plan, hydrology and hydraulics, geology, foundation investigation and design (including the field exploration, soil borings, and laboratory testing) and the structural design.
The IPET and several other engineering and professional organizations are studying the performance of the levees and floodwalls during Hurricane Katrina. Hopefully, the data that is being publicly released will help all interested organizations in reaching engineering-based conclusions as to how the protective structures performed during the hurricane.
Eventually, all releasable documentation from the New Orleans protection system will be available on the web site.
Much of the pre-Katrina documentation on the New Orleans levees and floodwalls was done before digital office equipment became available and includes large design and construction drawings and reams of paper related to contracts and other records. IPET personnel are working to digitally scan the documentation as quickly as possible...
The IPET web site isn't working yet. Soon, I hope.
The end of the month is a convenient place to close another "book" on this issue. Book III is now available.
Note: This entry continues the discussions of Book I: On the Levees of New Orleans. Book I concluded with the recommendation to appoint a federal Advisory Committee on Levee Safety as a first step to solving New Orleans water problems.