Geological Factors in Engineering

'But isn't all change caused by evil done by Man? All change to the environment therefore must be evil and fought to the last dollar. All storms are a direct result of unnatural Global Warming caused by Man. Man can control Nature.' The tinfoil hat brigades are still loose, so a rational explanation like this one will be rejected.

Give it up! New Orleans cannot be saved in the long run. Forbid rebuilding in the areas below sea level and just prepare for a total evacuation.

Skeeter-Just how much of the taxpayers money do you want to spend to "cure the problem"? Give it up! As I have stated before in another thread, building BELOW the water line "aint too bright"! James

Here's the other thread

http://cr4.globalspec.com/blogentry/5090#newcomments

It's not as simple as you portray.

There are much more grievous wastes of our resources.

James-I was just falling in with the "blame Bush for everything" crowd and attempting to point out that he did nothing to stop the hurricane, not its effects.

Legendary. Like King Canute's attempts to turn back the tide between 1016 and 1035 a.d.

King Knut (modern accepted spelling) knew he didnt have the power to turn back the tide and intended to show the fallacy of those spreading the rumours however tis turned into one of the earliest PR Stunt backfires as all he is remembered for now is failing and getting wet

On the general point about building blow the sea level - has anyone checked out building land in Holland (Netherlands, Pays Bas etc) which has been recovering land from sea for many years with or without fingers in dykes

Guest. I agree that the country of Holland needs to be protected-they have spent huge amounts of taxpayers money to hold back the sea. I agree with that decision. Lets face the facts here in New Orleans. I am not saying do not help the people that were displaced by Katrina. By all means, help your "fellow man". What I am saying is-no more REBUILDING in the area. Its going to happen AGAIN!!! James

It seems to me that when you have the land available above sea level, why spend so much more and increase the residents risk so greatly by building below sea level. From the information I have seen about the areas most devastated, it was the relatively newer residential housing (built in the last 50 years) that was the worst hit. It appears that the older parts of the city were above the flood stage. This means that the degree of local corruption so bad that they had been allowing building below sea level knowing the risk, since obviously they knew originally not to build below sea level. The level of 20th century corruption is NO was so bad for so long, but it was a State matter generally, and the Federal government had limitations on what it could do (and because of certain interests would do). Now that NO is basically funded by the Federal government they have started resolving the real problem, the corruption that allows people, like wealthy developers, to do anything with just a small donation to the right politicians and bureaucrats. I think this is one of the main differences between Holland and NO, it is not the local government officials responsibility to decide adequate public health and safety and acceptable risk (and thus not something that can be circumvented easily with developers money). People complain about the Federal governments response, but it was not their responsibility to save people that is the States responsibility (The national guard serves at the behest of the State Governor). FEMA comes in after the fact and supplies money and equipment to support people in the aftermath. We should really be addressing how a State government could be so corrupt, and require some strict changes in the State of Louisiana. If the people who have allowed such bad decisions to occur over time, for a small fee from private interests are now being prosecuted by the Federal Government and Louisiana is complaining about the oversight of the federal government. You can not expect them to stay clear of you and let you do any illegal thing you want and then expect them to be there on a whim when you fall down from the problems your previous corruption has allowed to occur.

We all recognize that levees are going to fail, they even fail in Holland also. However, we do not have the population density in this country and shortage of land that demands recovery of the Sea. Why take risks.

Rebuilding versus damage control. The end decision in this case seems to evolve around economics. The poor neighborhoods left in ruins should be swept of debris in order to prevent pollution from migrating into the marshes or oceans that feed the local ecosystem. Man made canals pushing north to Baton Rouge have shown provide a means for trade at high costs. Rather than fighting the inevitable and worrying about storm surges why not help the "Great Muddy find the path of least resistance and rebuild the city around a new entrance to the Gulf of Mexico that could prove to be a less expensive trade route. If we could save money on dredging and building monstrous levees maybe losing some livable ground is the best choice.

During Katrina, I read up on all of this. The issue is very complex, but what I most recall is that the there exists a serious inbalance in the way the lower Mississippi sediment deposit mass balance that cannot be sustained.

In a new river the current is strong and this causes the flow to meander significantly in the XY plane. As the river gets old, the velocity slows down and the river tries to straighten itself out. After about 1000 years, the river bed will have relocated itself, were it not for man. Up stream (50 miles more or less), the Army Corp of Engineers is regulating the flow in the lower Mississippi in an attempt to trick the river into not rerouting itself again. Basically the port of New Orleans is in the wrong place looking forward geologically. The will of the river cannot be overcome by man indefinitely. The river will have its way. Man can only slow down the process. There is an agreement of the flow split at the regulating dam that Army Corp of Engineers uses to control the flow downstream of the control structures.

At this point, I am to lazy to go back and read all of these articles again. But I encourage readers to to so.

Another point of interest as a peeve. The problem (New Orleans) is a river sediment problem while in the Netherlands it is more of a "sea" problem. If only this concept could be recognized, better discussions could be had. Then of course there is a political aspect to all of this.

O.K. guys, stop fighting. I have framed the problem.

I went back and found what I consider to be the descriptive summary of the problem of how man is attempting to control the mighty Mississippi and the effects on Louisiana.

The reference is from John McFee's "The Control of Nature" excerpts reprinted in "The New Yorker". Link attached.

http://www.newyorker.com/archive/1987/02/23/1987_02_23_027_TNY_CARDS_000348555

At a point 300 miles north of the mouth, "in defiance of nature a navigation lock on the Mississippi's right bank allows ships to drop out of the river dropping some thirty-three feet before going off to the west or south".

But before the locks were built, the water at this point just poured out into the Atchafalaya River. For decades, more and more water spilled out of the Mississippi into the Atchafalaya than during the previous decade. By the 1940's the volume into the new river had approached one-third. The river was again rerouting itself.

Since the control structure was built here, the U.S. Army Corp of Engineers has attempted to prevent the river from rerouting itself. This is done by forcing water to flow into the "old" channel which is the Mississippi on which Baton Rouge and New Orleans are located.

Had the diversion structures not been put in place according to the article the result would be "the demise of Baton Rouge and the virtual destruction of New Orleans".

I am not going to try here in this post to highlight the issue entirely as this one article is 32 pages in length. The curious reader is encouraged to research this article and others to get a better understanding of these complex economic, social, and political issues.

I read the New Yorker article you've provided (Lunch Hour)(All 27 Pages)

Wow is that long. But really interesting. To summarize, three of the main problems seem to be:

1. The mouth of the Mississippi wants you divert itself to a new outlet, the army core of Engineers is preventing this from happening.

2. The buildup of levies has made it easier for the Mississippi to flood and there are few outlets for the flood waters to go. I found it interesting and ironic that they sold swamp land to fund levy building, which eventually just caused worse floods when those swamplands were drained and protected with levies themselves.

3. Since sediment is not being allowed to be deposited during floods, land in New Orleans that is sinking is not being replaced. Land that previously was a buffer between New Orleans and the Gulf of Mexico.

That's tough issues to be sure, but I also note that the core of engineers doesn't seem to believe they can't do it. They just seem wary of the potential problems. Seems prudent to me.

Solution Found

People of Venice have live with water in the streets for centuries.

Venice is located on an island within a lagoon located between two rivers the Po and the Peave, neither comparable by any means to the Mississippi. Although both suffer from destruction due to past storm surges they are not comparable. New Orleans may look more like Venice if we chose to let the Mississippi find a new path into the Gulf of Mexico. In this case the city is no longer in the path of the river and flooded streets could be manifested into a canal system.

Mississippi Discharge

572,000 cu ft/s (16,200 m³/s),

Po Discharge (1500 m³/s),

Data obtained from Google:

http://books.google.com/books?id=8l9dfXu8OgYC&dq=po+and+piave+discharge&source=gbs_summary_s&cad=0

and Wikipedia:

http://en.wikipedia.org/wiki/Mississippi_River

Both are built on land formed from silt. Both of which the soil is sinking below the water levels around them. The Venetians just decided to keep building up. Living with water in the streets. The people of New Orleans as the land sank decided to build dikes. The only thing I see different is their methods to solving the same problem. How to reclaim the land as it sinks out from under them.

It can't be that bad to rip a quote from anchorman, "we agree to disagree"

New Orleans is fighting first a battle with a river and second the fight of submersion into the Gulf of Mexico. In Venice they may rely on the river to deposit sediment into the lagoon but they are't attempting to control the path of a river... Its like someone is on a boat with a harpoon hunting sharks and the other has a knife and chooses to swim with the catch of the day.

Too bad people weren't aware of the geology of the area when they settled there. The rive deposits it's silt when it slowes down and enters the gulf. As the silt settles the area rises then the river shifts to a lower location. Unabated by man, this creates a huge delta area. These areas are loaded with organics. Between them decomposing and the silt settling, the ground subsides and the river eventually comes back to the now lower area and deposits silt again thus keeping the land from ultimately disappearing as it does now.

Unfortunately all the land behind the levees is till sinking and everyone living there is in a hole that is getting deeer and deeper. Some areas are over 20 feet below sea level now.

They should never have built a single levee and no one should live in an area that is in a flood zone along a coast in a hurricane area. It is only a recipe for disaster and enoromus waste of resources.
Move everyone above the flood plan and let the river do it's thing. It will be far cheaper in the long run to relocate everyone than to continue to try and build higher and higher levees. Let the river renew the delta as it will provide protection for those further inland. Katrina won't be the last hurrican to hit the area. As far as getting bargages into the river, build a couple locks and raise the ships...alot easier than trying to lower the river...Da!

Some good points all round... post #1 is fine except the use of 'evil' is a bit strong...

The first guys who build alongside the river did it for good and obvious reasons it wasn't en evil plot to 'get those 21st century bastards'

What is missing is an actual 'plan'.

Say...for arguments sake...

Lets allow any industry which needs to be located there for reasons of geography, geology, access etc.
Support and protect that industry and infrastructure.

Do a similar thing for any historical or important areas of population.

Encourage the remainder to move out and use the vacated land as flood plain/protection extra waterways etc.

Ok I realise something like this isn't easy and can't be done overnight...but it would at least be a plan that was being worked towards. Everyone would know which areas were going to be protected (Hope fully decided on geographical grounds not race or wealth, although the two probably coincide due to historical influences......)

In the UK we have a plan...
It is the opposite of good sense... we'll build on the Thames flood plain when sea levels are rising!
Hope fully you guys could formulate a sensible plan!

Del

Why Del what a sensible suggestion! Must be from all those hrs of sunning & preening. Political & social momentum are hard to overcome.

I lived for a few years across the street from the London canal, in lakeview, it was odd to look across the street & see that the top of the levee was 8-10 feet above the top of the house.

Evacuating for a hurricane, is a relativly recent phenomena, standard practice was tape or board up the windows, stock up on your favorite beverage & have a hurricane party!

Just like anywhere else the best land costs the most money. The mostly lower income residents of the 9th ward, lived there because that's all they could afford & it's very close proximity to the central city.

Most of the old houses where built substansily off the ground, but of course this costs more. Shame on everyone involved for allowing standard slab as foundation, ground level buildings to be permited. Elevated, built on pilings structures fair much better when the enevitable big one's hit.

Maybe the local building code should only allow drydocked houseboat type construction?

Del - the "evil" remark was to poke fun at the rabid dog environmentalists who see any action of Man which affects the environment as bad. Also remember that the French who settled there were "evil" Europeans who were stealing the land of native people, so any results of what they did must also be "evil". LOL Just poking fun at the way some nuts look at it.

Have the same thing happening near where I live. There is a big flood plain beside a river which has been used as farmland. There is a sewer line running across it and the manholes are more than 20 feet above the ground. There hasn't been a serious flooding in years so big, rich, greedy developer buys the land and plans to build levees and a town there. Money is thrown at politicians who begin to support it and are willing to put the area within city limits until the people put pressure on them and they see reelection disappearing. So a small city across the river agrees to annex it across a county line and let it be built. Once finished though it will be the problem of that small city if there is a flood. Then they cannot afford to fix things, so two counties, the state and the federal government all become involved in relief and rebuilding, meaning all the taxpayers pay for it. The politicians and the developer have their money, so they don't care.

Once a place floods, rebuilding should be banned unless able to survive an even worse flood without damage. If the deepest flood is 12 feet then all structures must be 5 feet higher on solid piers or stilts or mounds of fill dirt with concrete or stone retaining walls. The old French Quarter of New Orleans is above sea level now and may not sink, but stop protecting the areas below sea level. Perhaps New Orleans will cease to be a major city over time, due to lack of room and the changes of Nature, so be it. Build a new port and a new city where there is no danger of flooding and listen to the geologists and those who study rivers when building it.

It may take a very long time for the sea levels to rise at less than 1/2 inch per year, but it doesn't make sense to build on any flood plain, anywhere. And if it is necessary to build there build the ground floor higher than any foreseen flooding plus a margin for worst case. But then who cares? The politicians and the developers will have their money and the taxpayers will be stuck with the costs. Guess where the power is since taxpayers won't or can't vote the idiots out or even stop them.

I agree with several of the comments mentioned above, we can't behave with ignorance nor can we control the evolution of the river. The worlds fifth biggest river is to large to live within human constraints. I believe the parts of New Orlean near 20ft bellow sea level wouldn't be the place for a redirected river. The higher portions of New Orleans may best exist as does in Venice. The new river route would most likely take place 50 miles or more up stream.

You know, 1,577 people died in New Orleans from Hurricane Katrina, and over 700 are still missing meaning potentially 2,300 people died from that hurricane in New Orleans.

September 11th, 2,974 people died. Why is it we've spent half a trillion dollars trying to "catch terrorists", yet nobody wants to spend any money to rebuild New Orleans?

Maybe I'm just a blame America first person, but that doesn't seem fair.

New Orleans future is in a political debate. People are worried about which districts are going to be protected from the rebuilt levees. the Army Corp of Engineers that researches the problem and gives probabilities that the rebuilt structures will withstand a category 5 storm surge are not accounting for the subsiding land under the dikes and have yet to propose a solution that would allow the Mississippi River to find a new course into the Gulf of Mexico.

Once the river is redirected catastrophic changes will impact the delta upon which New Orleans lives. I'd like to see some Venice like remnants of the city, rebuilt infrastructure around a new harbor and a new canal system to replace the several million dollars a year they pay to dredge the current path to Baton Rouge.

>>>>Why is it we've spent half a trillion dollars trying to "catch terrorists", yet nobody wants to spend any money to rebuild New Orleans?<<<<

How much money is enough to spend to catch and deter terrorists? How much money is enough to spend to raise and rebuild a ship (New Orleans) that has sunk?

When the Red River overflowed its banks in northern Minnesota several years ago, many folks lost their homes. If I recall correctly, the government (state or fed, I know not which) compensated the people for their land on the condition that they could not rebuild next to the river. I have not heard of this occurring on the gulf coast.

I, too, love the water and would like to live next to a river, but should tax money compensate me for my losses, if I am flooded out and my home falls into the river?

The issue is more complicated than that.

You have to factor in the costs of relocating the the businesses, some of which a vital to the continuing economic health of the entire country.

A very signifigent portion of the nations food, oil & chemicals flow through the port or are processed in the area. You must have people to perform these functions & the people need places to live in proximity to their jobs.

All new construction should have to meet more stringent building codes, similar to what has happened in earthquake prone areas.

Skeeter,

Have you ever been to New Orleans? It's actually quite dry, it was the massive storm surge of a category 5 hurricane that caused the devastation. That's called a natural disaster. You don't just write off a city because of a natural disaster. You act like we've had to rebuild New Orleans before. We haven't. This was a freak act of nature and those people need our help. It's no different than all the times San Fransisco has been rebuilt after Earthquakes. Actually it is different because that happens much more often.

I see you're from Montana. Do you realize you live next to a super volcano? Don't you see how foolish that is? Why do you live there?

Los Angeles is built in a desert next to a fault and is prone to massive earth quakes.
Las Vegas is built in the desert.
Washington D.C. is 1 foot above sea level and built on a swamp and susceptible to hurricanes.
Seattle is built next to Mt. St. Helens, a volcano that could do significant damage to that city.
New York City is barely above sea level and susceptible to hurricanes.

You know that we are supposed to have a 400 billion dollar deficit next year? Where is your outrage over that? In a year our National Debt will approach 10 trillion dollars and we as a country pay hundreds of billions of dollars in interest every year. You talk about money being foolishly spent, but you basically give the government a blank check when it comes to defense(Your Quote "How much money is enough to spend to catch and deter terrorists?"). How does that make sense? Look, I don't care if you want to be fiscally conservative, but you're not.

You're one of the spend billions, save millions crowd. That' not fiscally conservative, that's just living next to a super volcano and acting surprised when it erupts.

To Roger Pink... Your personal attack on me is childish and insulting. I have filed a complaint to the moderators.

Looks much more like an observation.

What's childish & stupid is suggesting we abandon a major center of commerce & culture & defending the continued build up of the military industrial complex.

Skeeter if you check Rodg