Lessons Learned from Katrina: How Can Engineers Apply Them for the Future?

[Astronuc]

It seems that communication is lacking. This has been a huge problem. The emergency workers can't talk with each other, and perhaps more importantly, there is no information getting to the masses of victims. One guy was just asking for someone in charge [with the N. Guard] with a loudspeaker. People need information in order to help reduce the panic. People seem to be starting to lose their minds.

Emergency Management - Hey, isn't that what FEMA is supposed to do?!?

OK - here's a revelation -

http://news.yahoo.com/s/krwashbureau/20050902/ts_krwashbureau/_wea_katrina_levee - on Yahoo, By Pete Carey, Knight Ridder Newspapers

The levee system that protected New Orleans from hurricane-caused surges along Lake Pontchartrain was never designed to survive a storm the size of Hurricane Katrina, the Army Corps of Engineers said Thursday.

The levees were built to withstand only a Category 3 storm, something projections suggested would strike New Orleans only once every two or three centuries, the commander of the corps, Lt. Gen. Carl A. Strock, told reporters in a conference call. Katrina was a Category 4 storm.

"Unfortunately, that occurred in this case," Strock said.

Strock said that the levee system's design was settled on a quarter of a century ago, before the current numerical system of classifying storms was in widespread use. He said that studies had begun recently on strengthening the system to protect against Category 4 and 5 hurricanes, but hadn't progressed very far.

Strock added that despite a May report by the Corps' Louisiana district that a lack of federal funding had slowed construction of hurricane protection, nothing the Corps could have done recently would have prevented Katrina from flooding New Orleans.

"The levee projects that failed were at full project design and were not really going to be improved," Strock said.

Strock's comments drew immediate criticism from flood-protection advocates, who said that the Corps' May report was a call for action and a complaint about insufficient funding, and that no action took place.

"The Corps knew, everybody knew, that the levees had limited capability," said Joseph N. Suhayda, a retired director of the Louisiana State University's Water Resources and Research Institute. "Because of exercises and simulations, we knew that the consequences of overtopping (water coming over the levees) would be disastrous. People were playing with matches in the fireworks factory and it went off."

Suhayda, an expert in coastal oceanography, said, "the fact the levee failed is not according to design. If it was overtopped, it's because it was lower in that spot than other spots. The fact that it was only designed for a Category 3 meant it was going to get overtopped. I knew that. They knew that. There were limits."

Some critics Thursday questioned the usefulness of levees, saying that all of them fail eventually.

"There are lots of ways for levees to fail. Overtopping is just one of them," said Michael K. Lindell, of Texas A&M University's Hazard Reduction and Recovery Center. "There's a lot of smokescreen about 'low probabilities.' Low probabilities just means 'Takes a long time.' "

Strock said that stopping the flow of water over the levees has proved to be "a very challenging effort."

Engineers have been unable to reach the levees themselves and have had to draw up plans based only on observations from the air, he said. "We, too, are victims in this situation," he said.

In Louisiana, Army Corps officials said they hoped that one break, in what's known as the 17th Street Canal, might be closed by the end of Thursday, but that a second break in the London Avenue canal is proving more intractable.

Short sections of the walls that protected the city from the waters of Lake Pontchartrain caved in under storm surges, including an area that recently had been strengthened.

A fact sheet issued by the Corps in May said that seven construction projects in New Orleans had been stalled for lack of funding. It noted that the budget proposed by President Bush for 2005 was $3 million and termed that amount insufficient to fund new construction contracts.

"We could spend $20 million if the funds were provided," the fact sheet said. Two major pump stations needed to be protected against hurricane storm surges, the fact sheet said, but the budgets for 2005 and 2006 "will prevent the corps from addressing these pressing needs."

Acknowledging delays in construction, Corps officials in Louisiana said that those projects weren't where the failures occurred. "They did not contribute to the flooding of the city," said Al Naomi, a senior project manager.

"The design was not adequate to protect against a storm of this nature," he said. "We were not authorized to provide protection to Category 4 or 5 design."

Ooops!

 

[Ivan Seeking]

Here's a couple of things that come to mind wrt the comm problems

Solar powered cell phones, or at least chargers are needed. And the little hand powered radios are huge in remote areas of Affrica and other regions where there is no power, this also seems a good option for disaster response and survival...and cell phones.

I just don't see how it is that even the emergency workers have no common communications network. They could bring in communications blimps, or even planes like those used to broadcast to Iraq during the war. But I'm not entirely sure why the emergency workers can't communicate. I assume that all towers are down.

 

[FredGarvin]

It is frustrating about the communication issues. However, how does one plan to have an unknown number of people come to an area from unknown areas in the country and expect there to be a protocol or way for them to immediately talk to each other? The only ways I can think of is to have standardized com. techniques throughout the country and to immediately establish the central point for all communications in the stricken area. I am sure they have to haveset up some kind of command structure by now. The question is, how fast can they get the com net to spread from the central point? That may be the real crux of the issue.

 

[engineer type]

Katrina Lessons Learned:

Every levee or dam ever built will overtop in a given storm event. Several factors are making extreme storm events more common. Human interference aside, climate change is the norm for the planet Earth. Our atmosphere is not a static system but our regulatory and engineering design tools do not reflect this fact and are not kept up-to-date. I work in the northeast US and it has been known for 15 years that the design storms legislated for use are not conservative enough. No disasters have resulted yet so nothing has changed. Some areas will naturally have increasing average rainfall, others will have increasing extremes in weather while others areas see decreases. Global warming due to any greenhouse effect only exacerbates some natural trends. The continued filling of wetlands and mangroves, especially on the gulf coast, contributes to increase flooding.

Urbanization also contributes heavily increasing flooding. Any area that is/was zoned for urban or commercial development should have compensatory stormwater detention. Relying on individual site owners to build and maintain stormwater detention facilities is largely a failed policy. It only takes 4-20 years for a small detention basin to silt in if it is not maintained. Many small site specific stormwater detention facilities actually contribute to major flooding events. A majority of urbanization takes place in the lower portion of watersheds near rivers and other water sources. Because site specific detention facilities associated with urban commercial sites are located in lower areas of the water shed they hold back stormwater until peak flows from upriver reach them. Flood control detention facilities on the middle to upper reaches of a watershed are the most effective at regulating the flood/drought cycle of rivers. Each municipality should be assed by the state on the amount and maximum percent impervious area of its existing and new zoning districts. The states should then use than money to create and/or expand their own stormwater management nature preserves like Clough State Park here in New Hampshire that can be centrally managed in conjunction with weather reports to reduce the flow in river systems ahead of the track of major storms.

Although not all of the specific measures I suggest below are practicable due to cost concerns a mix of a few could avert another disaster:

Only the highest half of New Orleans should be rebuilt. Dredge and construction demolition material from the lower half used to raise the grade of the portion to be rebuilt to at least 8 feet above sea level. The residents and businesses from the lower half of the city should be resettled in a new planned city in rural Louisiana, far away from any floodplains. Lower New Orleans could be turned into a mangrove park as environmental and flood storage mitigation of earlier destruction. Any portion of New Orleans to be rebuilt below the level of the Mississippi should be a canal based city like old Venice or Bangkok. This principle is applicable elsewhere, by removing old substandard levees and restoring the function of floodplains we can we can gain storage capacity to reduce pressure on other areas. Anyone who wants to remain living in the floodplain will have to mount their house on a barge or build site specific levees and pumps.

Storm-proof bunkers are needed on vital levees, pre-equipped with trucks or barges, excavators and sand bags and concrete mix and manned and maintained by trained volunteer organizations made up of people living behind the levee.

Planned failure (overflow) points spaced along levees, armored with pavement or stone located will cause less damage downstream and decrease pressure on unarmored sections of the levee system. In the New Orleans case this would have allowed some water from Lake Ponchatrain to be passed through the city and its flood pumps out to the Mississippi (obviously putting it back into Ponchatrain would have been futile).

Concrete crown bars for vital levees protecting urban areas should be installed after initial settlement of the levee is nearly complete, usually 10 to 20 years after construction. These crown bars are recommended by the Army Corps of Engineers but they seldom follow their own recommendation because of cost and shoddy construction at previous installation attempts.

Annual survey grade checks of the levee systems to monitor settlement identify low points. Better funded inspection and repair of undermining and seepage problems is imperative. Toe caps, bentonite clay cores and geotextile reinforcing are common repair solutions.

During an evacuation plan to have your cities school bus drivers take their normal routes with loud speakers. They can drive through neighborhoods announcing the evacuation and what times they will be back to pick everyone up. Then they make a couple more runs through the neighbor hoods to pick up everyone who doesn’t have a car and take them to safety.

Review by the office of Homeland Security of municipal, County and State disaster planning so that no one can get away with being as unprepared as New Orleans and the State of Louisiana obviously where. Punitive federal taxation in addition to garnering the wages of emergency planning personnel should be imposed on districts repeatedly failing readiness planning standards and testing.

FEMA and insurance companies need to charge higher premiums for properties located in low-lying, flood and hurricane prone areas. I for one am tired of my tax dollars being used to subsidize reconstruction of the same homes and businesses again and again. State and Federal Government funds need to be dedicated to emergency search and rescue, land swapping deals (taking disaster prone beach front and low lying properties for parks with destroyed buildings and giving back inland property for the insurance company to build on), strengthening but not repairing damaged buildings, and

 

[Astronuc]

It is frustrating about the communication issues. However, how does one plan to have an unknown number of people come to an area from unknown areas in the country and expect there to be a protocol or way for them to immediately talk to each other? The only ways I can think of is to have standardized com. techniques throughout the country and to immediately establish the central point for all communications in the stricken area. I am sure they have to haveset up some kind of command structure by now. The question is, how fast can they get the com net to spread from the central point?

Good questions Fred, but I would expect FEMA and Homeland Security should have already figured that out years ago. What we keep finding out, as was the case in 9/11 and other major disasters, is the system is not working, and has not been working. Communications was a problem in NYC. Whatever happened to lessons learned.

What have these people been doing? On what have they been spending the $billions?

Doesn't each state have a FEMA coordinator? Isn't there already a database with all the comm frequencies of each police, fire, emergency response unit? If not, why not?

Whatever happened to the Civil Defense infrastructure?

Given that Hurricane Andrew occurred 13 years ago, and they had comm problems back then, and 9/11 was almost 4 years ago, what was done to prevent the same problems?

Isn't it the job of FEMA and HS to ask these questions and find solutions - already?

I answered one of my questions, regarding CD infrastructure -

The Federal Emergency Management Agency - a former independent agency that became part of the new Department of Homeland Security in March 2003 - is tasked with responding to, planning for, recovering from and mitigating against disasters. FEMA can trace its beginnings to the Congressional Act of 1803. This act, generally considered the first piece of disaster legislation, provided assistance to a New Hampshire town following an extensive fire. In the century that followed, ad hoc legislation was passed more than 100 times in response to hurricanes, earthquakes, floods and other natural disasters.

President Carter's 1979 executive order merged many of the separate disaster-related responsibilities into a new Federal Emergency Management Agency (FEMA). Among other agencies, FEMA absorbed: the Federal Insurance Administration, the National Fire Prevention and Control Administration, the National Weather Service Community Preparedness Program, the Federal Preparedness Agency of the General Services Administration and the Federal Disaster Assistance Administration activities from HUD. Civil defense responsibilities were also transferred to the new agency from the Defense Department's Defense Civil Preparedness Agency.

from http://www.fema.gov/about/history.shtm

 

[Astronuc]

engineer_type raises some good points.

The New Orleans area is a drainage basin - and it needs special engineering to handle the volume of water that would otherwise OK the city. I heard a discussion about NO and its situation this morning.

Mangroves might be a bit problematic given the latitude of 30 N for New Orleans. The mangrove density is very low this far north, and the varieties are limited. I have pondered the idea for years since I read about the loss of the delta area at the mouth of the Mississippi and the salt water intrusion which has damaged the marshes.

Diversion areas, such as the Atchafalaya swamp, need to be properly developed. The current disaster is related to the location of Lake Ponchatrain drainage area to the north of New Orleans - the water has to flow south - and this may not be practical with a storm surge. If New Orleans takes a direct hit from a similar storm, the disaster will most likely reoccur.

Concrete crown bars for vital levees protecting urban areas should be installed after initial settlement of the levee is nearly complete, usually 10 to 20 years after construction. These crown bars are recommended by the Army Corps of Engineers but they seldom follow their own recommendation because of cost and shoddy construction at previous installation attempts.

Annual survey grade checks of the levee systems to monitor settlement identify low points. Better funded inspection and repair of undermining and seepage problems is imperative. Toe caps, bentonite clay cores and geotextile reinforcing are common repair solutions.

The question becomes, why wasn't this already done and in place. Preventative maintenance. Ground penetrating radar (GPR) has been available for years to ascertain the subsurface condition of things like levees and dikes - even seepage monitors.

Shoddy construction - it still happens today - WHY? I can't believe what I have seen around the country and in my area in recent years.

 

[Cliff_J]

As frustrated as I am watching TV, being embarrassed as an American with how poorly our government has responded to this horrible situation, this thread is really inspiring.

My hope is that we (as a country, maybe world) learn from blunders like this and take positive action to correct the issues at hand and not just play a game of sound-bites for the media.

Its like how Eli Goldratt teaches that in manufacturing the common pitfall is too much emphasis on local optimization and not on widespread optimization. So while it may be cheap for builders and profitable for the city to allow the zoning and building of homes on land no one wants because it is a floodplain, it costs us all more in the long run. Yet do we have a FEMA standard for what is considered acceptable? I remember seeing a Discovery channel program where residents who had been flooded 3 times (and rebuilt) fought until the end to try to prevent the moving of their city to higher ground. Living here in Atlanta, the infrastructure problems that I know about as a layperson are staggering. While not susceptible to natural disasters like other cities, its a bad spiral that seems to be accelerating with each area operating in conflict with the others. To borrow a cheesy cliche, more people would benefit if they could think globally and act locally.

 

[LURCH]

I don't think the government's response has been poore at all. The National Gaurd is there to try to restore order, a truly huge hospital ship with several amphibious rescue ships is steaming to the area, relief is pouring in from both the government and private citizens. The reaction of both the government and the majority of the people seems pretty great to me. Problem is, it's a reaction. We need pro-active solutions.

I think that the communication problem may already be on its way to getting solved. The reason the cell phones are not working is because all of the towers have been knocked out, but I have heard that the cell phone companies have already been planning to switch to satellites, rather than towers. But the logistical problem of various emergency services being able to communicate and coordinate via radios is pretty disappointing. This is a problem that can be solved and simply hasn't been, largely for political reasons, I suspect.

One of the lessons suggested earlier in the thread is that we need to come to a realization that all dams and levies eventually break. To me, this underscores the necessity for a planned to repair breaks quickly. I have an idea of my own, and perhaps someone with more education and practical experience in engineering could critique this:

It seems to me that a gridwork of reinforcement rod could be fashioned pretty quickly to match the dimensions of the break. This grid could be lowered into place across the break, probably by helicopter (since one of the main difficulties is actually getting to the break). Then, debris from some of the leveled houses and other structures could be shoveled into the river. Because of the leak, currents within the river or channel will be running swiftly toward where the break is, and the debris will be carried along by this swift current. The gridwork will not allow the debris to exit through the break in the levy, and very quickly the debris will "clog the drain".

I think it would work, and it wouldn't take a week to stop the flow of water. If this levy had been patched within the first 24 hrs, we wouldn't have this major disaster. We'd still have a flood and storm damage, but nothing like what we have now.

 

[Astronuc]

One of the lessons suggested earlier in the thread is that we need to come to a realization that all dams and levies eventually break. To me, this underscores the necessity for a planned to repair breaks quickly.

Yes, quite true.

I have an idea of my own, and perhaps someone with more education and practical experience in engineering could critique this:

It seems to me that a gridwork of reinforcement rod could be fashioned pretty quickly to match the dimensions of the break. This grid could be lowered into place across the break, probably by helicopter (since one of the main difficulties is actually getting to the break). Then, debris from some of the leveled houses and other structures could be shoveled into the river. Because of the leak, currents within the river or channel will be running swiftly toward where the break is, and the debris will be carried along by this swift current. The gridwork will not allow the debris to exit through the break in the levy, and very quickly the debris will "clog the drain".

I think it would work, and it wouldn't take a week to stop the flow of water. If this levy had been patched within the first 24 hrs, we wouldn't have this major disaster. We'd still have a flood and storm damage, but nothing like what we have now.

The problem is the hydraulic force, with water having a density of 1000 kg/m³ or 1 metric ton/m³. That's a lot of force! They have tried to drop 3 ton sand bags, but with little effect. Another problem is that breaches continue to widen by virtue of erosion.

But keep thinking about it. I don't want to discourage creative thinking, but rather encourage it.

 

[russ_watters]

The reaction of both the government and the majority of the people seems pretty great to me. Problem is, it's a reaction. We need pro-active solutions.

Bingo! New thread forthcoming...

 

[Cliff_J]

I don't think the government's response has been poore at all.

Well we can agree to disagree, but I find it disturbing we can airlift aid to a disaster half-way around the world in 2 days and it takes 5 days for aid to reach people in a disaster in our own country that had advance notice.

MSNBC and CNN have reporters in Mississippi talking to people who did not see any government representatives much less aid until Thursday. The reporters are raising the question of basically if they can reach the site (they stationed themselves nearby) and get aid from their churches in FL all the way out there by Wednesday, how the government agencies could not match or exceed that effort.

If that were not a difficult enough question, the situation inside New Orleans with the conditions inside the superdome or convention center are beyond belief to me. We airlift supplies and even coal into Berlin decades ago and yet can't load up a few C130 cargo planes and land in a nearby city and load up a few semis to get some basic aid to people?

There are reports that the local police in New Orleans have to loot their own food and drink, and they looted as much ammunition as they could from local stores to prevent it from reaching the thugs.

I realize the media will dramatize things to a certain extent, but they seem to have plenty of fodder for this one. Knowing that there was a plan drawn up for a Category 3 Hurricane with broken leevies only a year ago (the Hurricane Pam scenario) and they were unable to proact/reactively handle the situation better is pretty sad. Sure there will be people stranded in their homes, they knew this from the study that found 1/3 would refuse to leave. I view that as an unfortunate reality and that is being handled very well by a lot of dedicated people, I agree there. But when the officials tell people to head to a concentrated area that should make relief efforts easy, and we can't get them food and water for a week what rationale can we give?

 

[russ_watters]

Well we can agree to disagree, but I find it disturbing we can airlift aid to a disaster half-way around the world in 2 days and it takes 5 days for aid to reach people in a disaster in our own country that had advance notice.

Where do you get 2 days? According to THIS timeline, it was 5 days before the worst-hit areas were reached for the first time, which occurred when the first US Navy ship reached the area. And I'm sure you remember that the US was initially criticized for its light response. It was December 31, (the quake occurred on December 26) when the aid was raised from $35 million to $350 million. (as of today, aid for the response itself is $10.5 billion)

http://www.redcross.org/news/in/tsunamis/timeline.html says the first Red Cross personnel arrived in the area on December 29. They were administrators. The first relief teams arrive on the 31st.

For Katrina, THIS article says

National Guard troops moved into the downtown business district, and state police squads backed by SWAT teams were sent into scatter looters and restore order, authorities said late Tuesday.

THIS article from Wednesday morning discusses the mobilization of 125,000 local national guard troops, the dispatching of several navy ships, coast guard, air force, etc. that were in motion by then.

And technically speaking, aid reached New Orleans before the hurricane hit - that's what was going on in the Superdome.

I'm not saying the response was adequate, just making sure we're sticking to facts.
edit: Let me say that a little more forcefully - I'm not saying the response was adequate because I agree that it wasn't.

Edit - another one: http://www.cnn.com/2005/POLITICS/08/29/katrina.washington.ap/index.html article from Monday says FEMA was in place with supplies during the hurricane.

As the Category 4 the storm surged ashore just east of New Orleans, Louisiana, on Monday, FEMA had medical teams, rescue squads and groups prepared to supply food and water poised in a semicircle around the city, its director, Michael Brown, said.

 

[Astronuc]

I also cannot agree that the government's response was great, nor even good.

Saturday night - 36 hrs (Edit: corrected to 27 hrs below) before the eye came on shore, it was then 'known' that Katrina was a Cat 4/Cat 5 storm. That is when FEMA should have gone into action (proactive) and made arrangements to coordinate with folks in LA and MS. Then they could have simply checked a database (which apparently they just never got around to creating) for the appropriate comm channels (people, frequencies, equipment . . . .

The hurricane went through on Monday, and the appropriate aid wasn't really getting there until Thursday - at least from what I have seen on TV, and from comments by people there on the ground.

As for who did and did not evacuate. It would appear (I obviously don't know these people personally so I can't vouch for their financial situation) that most of those who did not evacuate simply could not afford to so (many many not have bank accounts), and they had no where else to go or no money if they got somewhere else.

Did the word get out. I don't know that either. I don't know how good or poor the communication is down there. I do know my friends certainly heard of the mandatory evacuation - but they also have internet access, TV's, phones, and are otherwise generally well-informed.

 

[russ_watters]

Saturday night - 36 hrs before the eye came on shore, it was then 'known' that Katrina was a Cat 4/Cat 5 storm.

I've been meaning to check that, since I used 24 hours in my scenario, so...

HERE are all the NHC warnings on Katrina...

Discussion #10 on Thursday, the 25th, at 11pm has Katrina over land (Florida), and dropping out of hurricane strength. The prediciton is for landfall on the 29th or 30th, with 85kt winds (cat2, I think). Nevertheless, it has this ominous statement at the end:

ALL INDICATIONS ARE THAT KATRINA WILL BE A DANGEROUS HURRICANE IN
THE NORTHEASTERN GULF OF MEXICO IN ABOUT 3 DAYS.

Discussion 16, on Saturday morning had it at 100kt winds, with 120kts predicted for landfall (slighly under what it hit with). This is the earliest I would consider an "execute" order on a disaster plan being reasonable - but only just barely. That's about 48 hours before hurricane strength winds hit land.

Discussion 20, at 2:00 Sunday morning, was an unscheduled report, and the first indication that it would be much bigger than a cat3 storm. Winds at the time were 125kts, with 130kts predicted for landfall. If cat3 wasn't enough, this warning should have been a trigger. 28 hours.

Discussion 25, at 11pm Sunday night, had winds at 140kts, with 135kts predicted for landfall.

Landfall was early in the morning on Monday.

-------------------

Don't mean to flood, but this is info I want for more than one thread.

 

[Cliff_J]

I get two days from the media - TV doesn't lie does it? No slant, spin, or agenda.

But according to that link, help was on the ground within a couple days on Dec28. Yes its labeled as inadequate, but that was a very large disaster and remote to much of the western world.

My simple point was that if, after the hurricane had passed and left the devastation behind, a church in Orlandocan have a truck driver make an overnight trip and get some ice, water, and food to affected people, then so too I expect FEMA can do the same. Dallas, Chicago, Atlanta and so on are all major metropolitian areas that would be a 1-2 drive away and should plenty of stock for 50,000 people for a few days.

Maybe we're disagreeing on semantics, I'm not saying its zero aid being given because that would be embellishing and non-factual. I'm just saying the aid is worefully inadequate for the number of people affected and the weak and sick are really being put into an even worse situation. If the news crews are painting a very inaccurate picture of the actual happenings, they are doing an amazing job. But it would appear that the tiny amount of aid actually getting to the ground is being hoarded by the strong attempting to over-compensate for the small of aid (even if that is only perception).

FEMA director Mike Brown admitted on one interview that they learned of the people at the convention center from news reports. How can the news reports have a significant piece of information unbeknownst to the director of operations and one day prior? If not communication with New Orleans/Lousiana officials, the national gaurd troops on the ground (Tuesday) with a status report of the situation should have been able to find its way up the chain of command to the director, wouldn't it?

4-5 days seems like a very long timeframe to deliver the supplies. In comparison when we lose a ballplayer to heat stroke/exhaustion its a big deal, removing the feeding tube from a person who did not make her wishes known in writing even has congress involved. I know in my state I could go to jail if I had a pet and left them in my car in the heat without water for an afternoon. So our standards as a society are pretty high, I think we should make efforts to uphold those as my opinion on the matter.

Sure the scope of the devastation and number of refugees may have exceeded expectation by an order of magnitude in New Orleans, but those problems can be mitigated and not (seemingly) ignored while soundbites are given stating the facts otherwise, that the people are 'being fed' with a past tense implication when in reality that means 'en route'. I can't imagine the news crews are all that talented at finding small pockets of people to distort the truth too much about the lack of relief efforts and lack of authority or medical staff or communication within the 2 main shelters. Nor the continuing reports from MS where reporters have one example of 600 people in a high school shelter (atown Bush visited this morning) who have received private assistance but have not had any communication with a government official.

My apologies if I've drifted too far from facts with opinions, but this is really irratating me that it is even possible for this to occur. There might be more than a hundred preventable deaths from lack of water or medicine. To me that seems exceedingly high.

 

[Astronuc]

Ivan and I discussed the evolution of information from NHC/NOAA regarding Kartina and the storm surge here

https://www.physicsforums.com/showpost.php?p=731868 in post 9.

It was Saturday evening, 7 PM and 10 PM, when NHC announced that Katrina was Cat 3 (with sustained with winds of 115 mph), but by 1 AM Sunday Morning Aug 28, Katrina had strengthened to a Cat 4 with sustained winds of 145 mph. That was 27 hrs before landfall (not 36 hrs).

Landfall was Monday (Aug 29) morning just after 4 am. I posted some satellite images
http://www.everything-science.com/index.php?option=com_smf&Itemid=82&topic=6337.msg56430#msg56430

Earlier on Saturday Katrina was just a Category 3.

 

[LURCH]

The problem is the hydraulic force, with water having a density of 1000 kg/m³ or 1 metric ton/m³. That's a lot of force! They have tried to drop 3 ton sand bags, but with little effect.

Yes, that's exactly the problem that this solution addresses. The sandbags are ineffectual because they rely on their weight and lack of buoyancy to sit in the rapidly flowing water and not be swept away. What is needed is an obstruction that is larger than the opening the water is leaking out of. Granted, the hydraulic force may be too great for the re-rod to withstand, and it may break. If that is true, then steal I-beams such as those used in the skeletons of tall buildings might be a more appropriate material. The important thing is the different approach. Don't try to use heavy things and hope that they will sink and sit in place. Instead, use structurally strong materials and span the gap.

Another problem is that breaches continue to widen by virtue of erosion.

I was thinking of a span that is significantly wider than the breach (say, by about ¹/₃). This should be sufficient to keep the two ends of the barrier anchored until the plug can be completed. Once the flow is decreased, erosion should stop.

 

[Astronuc]

Well think about how much steel bar - one inch diameter - say 20 feet high, 300 feet, with a 6 inch pitch, and perhaps a cage design so it has some structure. And the supports. How many tons are involved?

Then figure the coefficient of drag - at say 20-30 mph (29-44 ft/sec).

One might need some Skycranes to hand a structure.

Barge cranes may not be able to get close to a breach - or we need something like jack-up rigs.

 

[hitssquad]

The problem is the hydraulic force, with water having a density of 1000 kg/m³ or 1 metric ton/m³.

And that is just the density of clean water. Salty/dirty water is even denser.

 

[Kenneth Mann]

Much of the recriminations about response times are (at least, partially) unfair. The response was about as fast as could be expected - - after the fact. If all our leaders had decided resolutely and immediately, upon knowing that a "big one" was coming, to do all possible, it would have made little difference. It takes considerable planning and time to set-up an effective response (letting alone the preventive measures), for a disaster such as this one. This planning simply cannot be done in hours, or days, or even weeks to get us ready. It takes months, and more probably, years. If we want to pass blame for not responding faster, then we need to put it on all of us; going back at least fifty years, and that includes Eisenhower, Johnson, Bush I, Clinton, Bush II, All the Congresses, all the associated bureaucrats, all the Governors, all the mayors, all the state legislators, and all the rest of us. We simply kept rolling the dice, and New Orleans kept coming up lucky; until this time.

KM

 

[jaap de vries]

First of all, do not build dwelling and commercial structures in an area that is below the prevail water level. On the other hand, if one does, learn from the Dutch in the Netherlands - they seem to do it very well - but then they do not get Category 3 or 4 hurricanes.

I am from the Netherlands but for the past 2 years I have been living in Florida. This puts me in the unique position since we (in Florida) have been hit 6 times within close to a year, including katrina.

In Holland we had a disaster in 1953 killing close to 2000 people, about 0.02% of the population at that time. Eversince we (the Dutch) have comitted ourselves to build the greatest waterworks ever created, the Delta works, proving that water can be fought even while respecting nature. People can live below sealevel as long as we (engineers) comit ourselves to doing our jobs.

 

[Skyhunter]

According to the mayor of NO, and I don't know exactly how this is measured, but he stated that the storm surge drops one foot for every acre of intervening wetlands.

Also, don't forget, NO is just one town involved in all of this. Even if we ignore the general interpretation of Global Climate Change, meteorologists are predicting decades of increased storm activity as compared to our current definitions of "normal" activity. Of course, to me it seems reasonable to begin incorporating GCC into our thinking.

The Mayor doesn't know what he is talking about Ivan, but the wetlands are crucial because land reduces the strength of a hurricane, thereby reducing the surge

Sidney Coffee, executive assistant to the governor for coastal activities, said about 1,900 square miles of wetlands have disappeared from the area since the 1930s, and the receding continues at a rate of about 24 square miles per year. The erosion has a direct impact on New Orleans' ability to absorb the blow of a storm like Katrina, she said. For every 2.7 miles of wetlands, storm surges are reduced by about one 1 foot, she said.

http://www.msnbc.msn.com/id/9118570/

This is a good article. about wetlands and hurricanes.

 

[Skyhunter]

Indeed. Juxtapose this. In one part of New Orleans, a long line of school buses now submerged. In another part of New Orleans, tens of thousands of people in the Superdome because they lacked transportation to leave the city.

The city was using the metro buses for evacuation.

 

[Moonbear]

I heard on the news last night that engineers are now "speculating" (I put that in quotes because I'm not sure how strong the data is yet) that the levee failure was not due to the storm surge flowing over it weakening it or because the hurricane was just stronger than it was designed for, but that there were design flaws or defects of some sort in the levee that lead to it breaching. Did anyone else hear similar reports who could comment on it from a greater level of expertise?

I also heard they were bringing in large steel plates to cover the gap, apparently something that has not been tried before, according to the news again. I was wondering why this was not tried before. In a conversation with a friend of mine who used to be a civil engineer (he left the field a few years ago for greener pastures, so might not be fully up-to-date on stuff anymore), that was my first thought when I heard they were trying to stopper up the flow of water with sandbags, which sounded ridiculously infeasible to me given the size of the hole. I was thinking that if you just slid a long steel plate in place (with necessary braces to reinforce it of course), you could quickly stop the flow of water and then use it like a form to pour your concrete on the other side. But then he told me they would never do that, so I figured there was some reason that was a bad idea. (And, yeah, I rubbed it in a bit when I heard on the news that they were now doing just that. )

Another lesson that I think needs to be considered is that when climate conditions change or modern building practices have more stringent codes, it might not be acceptable to just keep grandfathering in older structures or to keep preserving old buildings out of an emotional attachment to the past. Sometimes you just need to tear down old buildings and replace them with newer construction, especially if you're in a vulnerable location, otherwise nature will come along and do the demolition for you.

 

[willib]

What the hell!
the Levee broke again , ok ,
What is the army corp of engineers doing ?? NOTHING !...
Ooo its too windy and too wet... waaaahhhh waaaaahhhhhh
so they are going to wait till the ninth ward fills up again,, idiots...
there was a camera guy filming the water comming in , standing on a good part of the Levee..with no corps of engineers in sight...
they booked outa there . and its not even going to meke a direct hit on New Orleans
Any thoughts on their responsibilities in this situation.??

 

[Moonbear]

they booked outa there . and its not even going to meke a direct hit on New Orleans
Any thoughts on their responsibilities in this situation.??

Yep, protect their lives before property. What could they do while the storm was hitting? You can't fly in helicopters with anything to patch the levee in high winds. You have to just let it fail and patch it when the weather conditions have eased up. This is why everyone was telling the mayor of N.O. that he was an idiot to even think the residents could start returning to the city until more of the infrastructure has been repaired. Those levees weren't repaired yet, they were patched. I think they need to sit down and evaluate the design of the levees in light of the strength of the recent hurricanes and the likelihood that they'll continue to get hit by strong hurricanes in years to come and consider rebuilding with a new design capable of withstanding higher storm surges than the current design.

One thought I have is that they need more than one levee wall. The government should use the eminent domain laws to buy up property within a reasonable distance inside the levees and leave it deserted, then build a second levee within the perimeter so if the outer levee breeches, there's a second levee as back-up. If they want to clean up the land between the levees, they can put in a park or something that won't have anything built on it so won't be a big deal if it floods in the future. Sure, it'll be expensive to build, but considering the expense of rebuilding an entire city, it seems worth considering now while everything in that region is pretty well flattened anyway.

 

[russ_watters]

This is why everyone was telling the mayor of N.O. that he was an idiot to even think the residents could start returning to the city until more of the infrastructure has been repaired. Those levees weren't repaired yet, they were patched.

Realistically, I think that it will be a good month or two until even temporary repairs can be completed. I don't think it would be wise to repopulate those parts of the city in danger until the hurricane season ends in six weeks.

I think they need to sit down and evaluate the design of the levees in light of the strength of the recent hurricanes and the likelihood that they'll continue to get hit by strong hurricanes in years to come and consider rebuilding with a new design capable of withstanding higher storm surges than the current design.

It is something they've been kicking around, but unfortunately, governments don't tend to close the gate until the horses have already run off. I think there is a good chance the government will make that choice now, considering the ~$10 billion or so it will cost to upgrade the system is peanuts compared to the ~$300 billion or so that will be spent due to this 1-2 punch.

One thought I have is that they need more than one levee wall. The government should use the eminent domain laws to buy up property within a reasonable distance inside the levees and leave it deserted, then build a second levee within the perimeter so if the outer levee breeches, there's a second levee as back-up. If they want to clean up the land between the levees, they can put in a park or something that won't have anything built on it so won't be a big deal if it floods in the future. Sure, it'll be expensive to build, but considering the expense of rebuilding an entire city, it seems worth considering now while everything in that region is pretty well flattened anyway.

I tend to think that would be overkill. If the levees are built to the same specs, if one fails, the other will likely fail as well. I think the solution needs to be to simply build the levees to withstand the strongest storm imaginable: we're talking 50 feet of storm surge. Such a levee would be so massive, though (they are several times wider than high) that the govt would probably need to exercise eminent domain anyway.

 

[russ_watters]

I heard on the news last night that engineers are now "speculating" (I put that in quotes because I'm not sure how strong the data is yet) that the levee failure was not due to the storm surge flowing over it weakening it or because the hurricane was just stronger than it was designed for, but that there were design flaws or defects of some sort in the levee that lead to it breaching. Did anyone else hear similar reports who could comment on it from a greater level of expertise?

I hadn't heard about that.

I also heard they were bringing in large steel plates to cover the gap, apparently something that has not been tried before, according to the news again. I was wondering why this was not tried before. In a conversation with a friend of mine who used to be a civil engineer (he left the field a few years ago for greener pastures, so might not be fully up-to-date on stuff anymore), that was my first thought when I heard they were trying to stopper up the flow of water with sandbags, which sounded ridiculously infeasible to me given the size of the hole. I was thinking that if you just slid a long steel plate in place (with necessary braces to reinforce it of course), you could quickly stop the flow of water and then use it like a form to pour your concrete on the other side. But then he told me they would never do that, so I figured there was some reason that was a bad idea. (And, yeah, I rubbed it in a bit when I heard on the news that they were now doing just that. )

It seems like a good idea to me, but where do you get a steel plate that size and how do you put it there? They were kicking around a similar idea: putting a large barge in front of the breach.

Another lesson that I think needs to be considered is that when climate conditions change or modern building practices have more stringent codes, it might not be acceptable to just keep grandfathering in older structures or to keep preserving old buildings out of an emotional attachment to the past. Sometimes you just need to tear down old buildings and replace them with newer construction, especially if you're in a vulnerable location, otherwise nature will come along and do the demolition for you.

I'm generally not a big fan of historical preservation: it costs an enormous amount of money and just because a building is old does not automatically imply that it has historical value. But the political pull of historical preservation is strong enough that rather than demolish buildings that don't meet new codes, they'd just spend more money reinforcing them.

In Philly, people spend hundreds of thousands of dollars bracing the facades of old brick row-homes (they tend to bow outward as the house settles). Every now and then, they have a blowout, where the facade literally explodes onto the street. Such building should just be demolished.

 

[Astronuc]

In order to comment on the design of the levees, one would need some detailed diagrams, particularly of the cross-section.

I have heard recently from comments by Corp of Engineers staff that there was scouring of the levees, which had not been previously detected. This certainly could have undermined the levee.

Perhaps the levees are a combination of concrete and compacted fill. Unless the fill is properly engineered, water may seep into the structure and weaken it, e.g. water reduces the internal cohesion of the fill, and basically the levee creeps/flows and then fails. Water infiltration may occur because the hydraulic pressure, which increases with water depth, forces the water into the levee structure. Here is where one needs the details of the design.

I am wondering if the structure was simply reinforced concrete slab/form set over a compacted Earth fill. This is the type of structure used in channels or concrete bayous or along freeways. Water getting under or behind the concrete can undermine the earthen fill.

The other problem is corrosion of the reinforement bar in the concrete. If the concrete is not of the correct composition, is not mixed right or cured properly, it can be relatively porous, and over decades, Cl (chlorine ions) can infiltrate and cause corrosion of the steel rebar. Perhaps that is one factor in New Orleans levees.

Anyway, there will certainly be an investigation, which hopefully will shed light on the failures.

 

[Moonbear]

I have heard recently from comments by Corp of Engineers staff that there was scouring of the levees, which had not been previously detected. This certainly could have undermined the levee.

Maybe that's the "defect" I heard them mention on the news yesterday.

 

[Moonbear]

It seems like a good idea to me, but where do you get a steel plate that size and how do you put it there? They were kicking around a similar idea: putting a large barge in front of the breach.

That's what they pay the engineers to figure out? Okay, it seems they were using 60 ft plates (I think I heard that on CNN). I'm not sure how they were doing it, but since the breach was 200 ft wide, I guess it wouldn't be quite as easy as I was thinking (and they might not have been able to do this sooner if they needed to get that plate custom manufactured for the job). I kind of like that barge idea. Maybe they need a Navy Corps of Engineers instead of an Army Corps for this job; just park a big ship planned to be decommissioned in the hole. (Shhh...Don't tell my friend that I wasn't quite right about that steel plate idea, he'll never let me live it down after I rubbed it in.)

 

[russ_watters]

I kind of like that barge idea. Maybe they need a Navy Corps of Engineers instead of an Army Corps for this job; just park a big ship planned to be decommissioned in the hole.

I don't know where else they have boneyards, but Philly operates one where they have dozens of WWII ships parked, including supply ships (huge, but maybe not strong enough) and battlecrusiers (a foot of armor makes them pretty strong).

 

[Astronuc]

It seems like a good idea to me, but where do you get a steel plate that size and how do you put it there? They were kicking around a similar idea: putting a large barge in front of the breach.

The idea of getting a ship or barge in the breach is complicated because of the geometry of the barge or whatever vessel - it has to fit just right or the water will simply flow around it and wear out a larger hole.

When the breach was small (100-200 ft), it would have been difficult to maneuver a barge 'just so' while the water was flowing through the breach, and then the barge, which would be floating, would have to be rapidly ballasted so sink it. In fact, I believe I saw one image in which a barge had floated through one of the breaches into the neighborhood behind.

Elsewhere, when construction is taking place along waterways, barriers are built with interlocking corrugated steel channels. Perhaps that would have taken time to arrange though.

Anyway, I found an interesting article on the levees of the West Jefferson Levee District (WJLD). It highlights some of the problems with the levee system. I am not sure if this levee (the eastern side of the canal) was one that failed.

Levees are supposed to line both banks of the canal to protect homes and businesses from high water. The west side levee is a solid continuous structure built in 1991 with federal funds by the Army Corps of Engineers. Containment structures on the east side, however, are a hodgepodge of wooden bulkheads, cement sea walls, consolidated earthworks and even an abandoned barge.

Maintenance of these structures is officially the responsibility of property owners there. Most of these back levee owners are industrial businesses involved in construction, fishing and offshore petroleum operations.

“The east side is not really a levee system, and there’s a difference in elevation between the two sides,” says Giuseppe Miserendino, deputy director of the West Jefferson Levee District (WJLD). “Water would spill over the east side of the canal if there were a tidal surge.”

Tidal surges pose serious dangers in that section of Louisiana where many residential and commercial areas reside below sea level. In fact, the entire system of canals, levees and river locks built in the area has been constructed to protect New Orleans and outlying suburbs from those tidal surges on the Mississippi and the Gulf of Mexico following a major storm.

from - http://www.pobonline.com/CDA/ArticleInformation/Article/1,9169,74573,00.html

 

[amuron]

Someone posted earlier in the thread.

"It is both a matter of public policy, as well as engineering, and engineers need to be heard in the public forum."

As a rule, we tend to ignore politics and go about our business... or at least I do. I spent 2 years at a state govt appointed position while holding down my engineering job, and had my fill of it. When the position ended, that was it for me.

A friend who retired from NBS (yes, before they became NIST) told me the DC beltway had one of the highest concentrations of multidisciplinary scientists and engineers compared to anywhere else in the country. But at the same time, he also told me that virtually none of them were active in politicis due to all the BS. I think too many of us come to the same stance. We let politicians do their bungling, shake our heads and walk away in disgust.

Otoh, if engineering had a decent voice, imho, their might have been some proactive cost effective solutions that would have made a difference.

Ron

 

[zhen]

I just wonder why they don't think about those underwater city project?
because no matter what the government do, another hurricane will still come, the place will be flood again... the best thing to do is to build underground or under water city...