i know it’s insensitive, but after katrina, why rebuld below sea level AGAIN? just send all the trash in the country and build a new new orleans. or is the land too swampy for a land fill?
Yep, too dynamic to be a sanitary landfill. You want a place that’s geologically stable, water table not too crucial that leachate will not affect a lot of people.
On the other hand, a swamp is basically a natural septic tank. So small amounts of black water may be dumped with minimal effects. And natural swamp denizens (reptiles, amphibians, insects, certain fish) can survive on filth. But no, the scale of human waste disposal is too big for any swamp.
In addition to what is said above, it’s my understanding that the land on which much (not all) of New Orleans stands is persaturated, deep former river slurry laid down over the years, behaving much like a thoroughly saturated sponge, and like the sponge will compress and exude water if anything heavy is put atop it. TTBOMK these parts of the pre-Katrina city are by and large not rebuilt. (The French Quarter and some other well-known parts of the Big Easy are on natural levees and other landforms that keep them above water level, absent a Katrina-type disaster.
New Orleans is built on the delta of the Mississippi-and indeed, it is low density soil. Because of this, the city is sinking at about one inch per century. The city has dealt with this by raising the dams on the sides of the river (levees), and this solution leads to more problems (the water table rises). Its quite amazing to stroll around Jackson Square-and see ships passing on the river (above your head)! What can be done? Not much, because the past century has seen the destruction of the delta-the forced straightening of the river channel means that the alluvial soil brought down dumps into the Gulf of Mexico (not replenishing the delta as it did in times past). Hence, the delta marshes south of New Orleans are washing away.
My personal belief is that one giant spring flood will cause the river to burst through the dams at Baton Rouge (200 miles upriver), and the “might Miss” will establish a new delta via the Achafalaya river west of NOLA-and New Orleans will cease to be a port.
In case that’s not clear, a landfill tends to have more or less nasty stuff (toxic chemicals, bugs from rotting food, etc.) that can get washed away if water runs through it, even water that’s moving underground. So we try and build landfills so that groundwater can’t get in or out. There’s usually a plastic lining and so forth as a first line of defense, but you also want to put it somewhere where the ground is basically dry as much as possible, so there’s less chance for lots of water to move in if there’s a hole in the lining.
So next to the river, below the river level, is a bad place for landfills.
There are landfills around New Orleans, sometimes with their own unique challenges. I saw one that was being expanded; they’d already dug out the space and had some plastic lining down, but hadn’t started dumping trash yet, so rainwater collected on the plastic and made a bunch of pools.
When I was there, they were rousting an alligator out of the pools.
If the river had been left to its own devices, this might have happened by now. The Achafalaya River is a natural distributary of the Mississippi River. Some time ago, the Powers That Be noticed that the Achafalaya was taking a greater & greater share of the Mississippi’s water, so they built that huge dam to keep it from getting worse. If that dam ever fails for some reason, it’s quite conceivable that the Mississippi might end up cutting a new channel to the sea, and New Orleans will be left [del]High[/del] Low & Dry.
Even if one were to dump packed earth into the low areas of NO and raise them above sea level, this would only be a temporary fix. As mentioned already, NO is sinking and it would only be a matter of time before the problem started again.
It is essentially an artificially created living space, and I’d much rather see it returned to its natural state and designated a wildlife preserve. Let the planet take it back. I’m okay with light modifications to make patches of land more suitable to human habitation, but I draw the line just short of that situation.
I’ve been to New Orleans a few times. It’s an interesting locale, but I can’t say I’d miss it.
Read “The Control of Nature” by John McPhee for a good summary of the situation, and how that dam was on the brink of failure in the past.
I’ve long thought that after Hurricane Katrina, we really needed to have a frank national discussion on whether rebuilding New Orleans was even a good idea, given it’s rather untenable location.
When (not if) the same sort of flooding happens again, hopefully we’ll do the sensible thing and tell the displaced residents that we’ll gladly help them find new housing – somewhere else.
For the record, I have similar feelings about people who live on barrier islands. If you want to live there, fine, but don’t expect us to fund efforts to rebuild houses that are 100% guaranteed to get wiped out by the next passing hurricane.
Google ‘North Sea Protective Works’ to see how protecting New Orleans could be done. The Netherlands has been reclaiming land from the ocean for a long time, a large % of their population lives below sea level, and every once in a while they add a province without taking land from another country.
The projects are extensive, and expensive, but they made it a priority for their nation. We just have to decide New Orleans is worth it. If not, then we should stop throwing more resources at an unwinnable situation and let the sea have some of those areas back. You really cannot implement a half-assed flood protection system - we need to go all-in, or forget it.