Thursday, September 08, 2005

The Case Against Rebuilding New Orleans

Shortly after Katrina slammed into the US Gulf Coast, the Speaker of the House of Representatives Dennis Hastert went on the record, saying that federal money to restore New Orleans “doesn't make sense to me.” While he later backed off those comments, that question continues to linger out there like the floodwaters that lap at the houses in the Ninth Ward—should we rebuild New Orleans?

From a Geological stand point, the quick answer would have to be no.

New Orleans, as everyone has now learned, is situated on the ground between the Mississippi River and Lake Ponchetraine in a natural delta. Constant deposition of sediment is required to sustain any delta. Without it, erosion from tidal and wave forces will eventually erode away the formation. Hurricanes can accelerate this process dramatically. Worldwide, this erosion can be observed in almost every river delta that has had its flooding action halted by damming of the upstream head waters or channelization via artificial levee construction. In New Orleans, both man made interventions affected the Mississippi River’s flow.

As concerning as that may be, the pumping of groundwater and later, oil and natural gas, further increased the rate of subsidence to where portions of the city are now more than 20 feet below sea level.

With land subsiding in the interior and eroding at the fringes, the conclusion is clear. This area is not inhabitable without significant protection and mitigation, with each year requiring greater measures (higher levees, stronger flood walls and bigger pumps).

As if short term concerns are not troubling enough, over the long haul this area also has to fear delta-switching as well. The Mississippi, like all other major rivers undergo a process whereby the main channel periodically switches location within the delta. This process is well understood by geologists and hydrologists but ignored by most other individuals, due in large part to their infrequent occurrence. Delta switching can occur every few hundred years, when the main tributary becomes so excessively long that river water has to travel an ever longer distance to reach the sea. A longer length means the main channel flow slows compared to the other branches. Eventually one of those branches “captures” the flow of the original main channel and becomes the new main channel, due to its shorter distance and faster flow.

As luck would have it, the Mississippi is due for such a switch. In fact it is well over due. A couple hundred miles upstream from the mouth of the Mississippi River, trouble of another sort is brewing. The Army Corps of Engineers is locked in an epic battle to prevent the Old/Atchafalaya River system from capturing the river. While the story of how this happened is thoroughly entertaining and can be read
here or here, the gist of the matter is that in the 1950’s the Corps became aware that ever-increasing percentages of Mississippi water was flowing into the Atchafalaya River. The problem was so severe that it would have been a matter of few years to a decade or so before the Atchafalaya would have irrevocably captured the Mississippi. To stop this, the Army Corps constructed a massive control structure that prevents the Red and Old Rivers from taking more than 30% of the Mississippi waters. So far that has worked, despite a few close calls during major river floods.

To fail would doom New Orleans (if it had not already been destroyed) and Baton Rouge to backwater status. The now bypassed Mississippi would clog with sediment and in its lower reaches become brackish. Industries and cities dependent on its fresh water would die and shipping would only be possible courtesy of yearly dredging. The distinctive “tip” of Louisiana, deprived of sediment would be lost to the Gulf of Mexico. Meanwhile, Morgan City on the Atchafalaya would need serious flood protection to withstand the “responsibility” of becoming the main river channel.

Geologically, the cards are stacked against New Orleans. Given the passage of time, the area known as New Orleans (and Baton Rouge) would ordinarily be relegated to the annals of history, destined to become the next lost city, overrun by wild life and studied by future civilizations (if there are to be any). It is only through the application of massive amounts of energy, is nature held at bay. But nature can only be delayed, not denied. For without constant supervision, work and physical investment, the forces of nature will triumph in the end. In fact they are already beginning overwhelm our best laid plans.

As usual, it all boils down to energy.

We know what geological forces we face in the delta and what measures we have to take to over come them. The question is, will we have the energy to continue to do so? With the recent destruction of New Orleans, will we also have enough energy (and other resources) to rebuild what was lost while protecting from future calamity?

Again the answer would have to be no.

Our global energy supplies are stretched thinner than ever, even before Hurricane Katrina struck. As we pass through the point of Peak Oil in the next few years, our energy situation will become evermore serious and dire. This will affect the pace of any rebuilding (if it does indeed commence soon) by driving up the cost of fuel and construction materials so much so that people cannot afford to rebuild. Eventually it will rob construction firms from most forms of mechanized activities unless governmental priorities resulted in direct access to fuels and the necessary petroleum-based chemical feed stocks.

Secondly, the spiraling cost of oil and other forms of energy would suck the economic life out of the country, depriving the government of the will or the means to pay for an increasingly costly reconstruction effort. Levee rebuilding may become a casualty to an energy driven economic depression. First rate ideas may yield to third rate solutions that prove to be more cost effective than technically effective. Perhaps if we were further away from peak oil, more could be accomplished.

Finally, if an economic crash leads to warfare or dramatic drops in available fossil fuel stocks that affect the food production and distribution networks, basic human survival would be placed at risk. Hungry people don’t build levees. Famished families do not build houses. While not in the immediate cards for the human experiment, it will eventually occur if we fail to develop a sustainable path for civilization to take. There simply is no way around that fact.

Geological forces cannot be stopped. The laws of thermodynamics cannot be broken. Humans cannot exceed their global carrying capacity. These is simply no room for argument on these points

The complete rebuilding of New Orleans flies in the face of all of these. Unless we can continue to forever increase our global energy supply to overcome all of our past “protective” measures to keep the waters at bay as well as prevent all of those future forces (also including rising sea levels) from impacting the city, we are doomed to fail. Since never-ending growth is out of the question, at some point we will face a point of reckoning, a time when all of our past actions come to the forefront and haunt us.

Nothing lasts for ever and everything on this planet from amoebas to zebras will succumb in the end. So too will everything that we humans create and build. Sooner or later that means whole settlements will fail and be destroyed. It has happened time and time again throughout history, for a variety of reasons. The sooner that we all understand this, the better we are for it.

Dennis Hastert was right to question the future of New Orleans. It was just for the wrong reasons. Better to conserve what little resources we have left to improve or preserve what still works elsewhere. As hard as it is to believe, New Orleans’ time has come and gone.

Morgan City anyone?
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Turns out Joel Garreau, the author of Edge City and the Nine Nations of North America has written on this very subject. More info than my post but then again, his day job is writing...
Check it out here:

2 Comments:

Blogger Engineer-Poet said...

Overall an excellent essay, but there's one error:

"Humans cannot exceed their global carrying capacity."

There's an over-simplification in that, and that is the assumption that there is a fixed carrying capacity based on the needs of the species "homo sapiens".

It's just not true; it is defined largely by technology.  Consider staying warm in winter.  If you live in a wattle-and-daub hut with an open fire, you're going to burn a lot of fuel and still remain pretty cold.  On the other hand, if you have a house built of straw bales or SIP's insulated to R-40 and using good windows, you'll be able to stay toasty for a lot less fuel than the low-tech solution.  Some houses are sufficiently well designed and built that they can essentially heat themselves in winter, even in Vermont.

The list goes on; the average suburbanite's driving could easily be powered by PV panels on the roof of their house instead of by imported oil.  There are examples of technologies like this for most categories of energy or material consumption.  Taken together, they point to the possible carrying capacity of Earth being close to current population levels for longer than our planning horizons can see.

You can say that we don't have enough of these technologies in use.  You'd be right.  But that doesn't mean we should be planning for die-offs when we could be planning for wastewater gardens feeding into tilapia ponds instead.

And as long as you're in Oregon, you might want to start a citizen initiative to overturn the hybrid tax and buy yourself a Prius and some solar panels so you can have a renewably-powered GO-HEV when the conversions become available.  Become an example as well as a voice.

9/09/2005 11:49 AM  
Blogger Lisa Says said...

Thank you! I was thinking the same thing. If we have to build level 3, 4 or 5 levees just to have a city--even something called a 'sea gate' is being seriously considered by New Orleans government-- wouldn't the average person get a clue that it might be best to move inland a few miles? I don't know how far that would mean. The river in the city was above people's heads. Now, that just screams 'futile effort' to me.

Like you said, serious problems "will eventually occur if we fail to develop a sustainable path for civilization to take. There simply is no way around that fact.
Geological forces cannot be stopped. The laws of thermodynamics cannot be broken. "

Reflective of the Borg: "Resistance is futile." We live WITHIN the ecosystem, not outside of it. I saw on the weather channel that, like clockwork, hurricanes get stronger when they pass over warm sections of the ocean. And a scientist said on a news program that, while we cannot point to one thing that is caused by global warming, it moves the myriad of circumstances closer to an outcome.

Ie. the highest number of hurricanes in one season seen in a long time. Ie. Hurricanes Katrina, Rita and Wilma.

The engineer-poet said, "You can say that we don't have enough of these technologies in use." Which I believe is the only problem we have. As Gandhi said, "The difference between what we do and what we are capable of doing, would suffice to solve most of the world's problems."

Its up to us to make money an accurate gauge of what is really valuable and meaningful in our society. We, as consumers, decide what the value of money is. Corporations only follow the dollar. Let's choose how we give it.

11/05/2005 10:27 AM  

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