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This is alarmist BS. I worked on the surveys and cors equipment that directly measures subsidence in Louisiana, and have worked on many of the levees and other

This is alarmist BS. I worked on the surveys and cors equipment that directly measures subsidence in Louisiana, and have worked on many of the levees and other coastal civil works. Relocation? For a problem that hasn't happened yet and isn't likely to happen in the foreseeable future is absurd. New York City is at a much greater risk and will be inundated long before New Orleans. The fastest rate of subsidence in New Orleans is/was due to organics in the soil decomposing once the groundwater table was lowered (drainage projects going back 300 yrs), allowing oxygen to infiltrate. This decomposition is mostly complete in most areas of the city. Piles under everything from skyscrapers to personal homes penetrates the organic layers, so buildings don't subside even if the ground does. The biggest risk to the city and state is environmental activists, the EPA & the Army Corps of Engineers, and the largely untouchable Mississippi River levee system, preventing the delta land building process that counteracts subsidence by depositing new sediment in yearly floods. Additionally, erosion/ runoff prevention and dams through out the Mississippi, Missouri, and Ohio river watersheds have decreased the amount of sediment flowing down river, and results in less sediment available for natural land building. The coastal barrier marshes and islands are dying because we've stopped the natural processes that sustain them. Each mile of marsh results in the natural lowering of storm surge by 1/2' to 2'. The federal government, environmental groups and others fight the restoration of these natural processes. For example, they argue fresh water introduction will hurt dolphin populations in coastal bays, but they are only capable of being there in the first place because of man made interference: the bays were freshwater until the levees cut off their natural supply of freshwater. As for global warming? Infrastructure, business and homes are amortized at 30yrs or less. Maybe up to 50yrs for very large civil projects. Worst case sea level rise estimates easily gives New Orleans 300+ more yrs, likely much longer, a time frame longer than the current age of the city.

pfisch 5y ago
It is and it isn't. His scenario won't happen but what will happen is fairly similar. No one is going to make large capital investments in a city that gets blown away all the time. Every time New Orleans takes a big hit like this people leave, and less money is put back into the city. The population of New Orleans was higher in 1980 than it is now. I am from New Orleans, and since Katrina the infrastructure has been getting worse, not better. There probably isn't going to be some big dramatic event that kills New Orleans. It will just keep shrinking and pulling in towards the French Quarter as it gets hit repeatedly by extreme weather events. It will just become smaller and more impoverished over time until it is maybe abandoned at some distant point in the future. It will be a death by inches.
- beerandt 5y ago
  Cities across the country will die much sooner from economic and political reasons than New Orleans will die from subsidence. (Although New Orleans is likely included in that first set as well, based on current leadership.) But we don't discourage economic development in those places. My amortization comment was perhaps not explicit enough, but as long as people think the city will last beyond amortization periods, future abandonment/inundation/end-of-days predictions are not a rational reason to preclude investment. Most businesses shoot for a payback period of 10 years or less. I expect you're right about slow death, but it won't be for climatic or geologic or hydraulic reasons. Fear of those reasons might contribute, but then we've gone full circle back to "alarmist BS".
  - pfisch 5y ago
    You're being unrealistic about the reality of living in New Orleans and the level of capital investment in New Orleans vs Baton Rouge or other cities that aren't under constant threat of destruction. People just aren't going to come in and build nice shopping centers in New Orleans. It isn't happening and hasn't happened. Why would it when they could build in another city where it won't get destroyed and it will be more profitable? It is extremely stressful every year watching hurricanes and wondering if your house is going to be destroyed. Then when your house is destroyed it is no fun at all to be involved in gutting it and rebuilding it. On top of that no one is making investments in the city so it hardly has any good jobs. It isn't alarmist to recognize what is already happening. The climate is creating more extreme weather events that are undermining New Orleans. It doesn't need to be some fake "The Day After Tomorrow" style disaster that people can easily recognize. It is an insidious, slow, hollowing out of the city. How many water boil warnings have their been since Katrina? How often has electricity been inconsistent in the city? I can tell you it happens a lot more now than it did before Katrina, and it is going to be even worse after Ida.
    - jsight 5y ago
      How many homes were destroyed and will need to be rebuilt due to ida?
dylan604 5y ago
>Piles under everything from skyscrapers to personal homes penetrates the organic layers, so buildings don't subside even if the ground does. The sinking building in SF would like to differ with this. If a building is not built correctly, all bets are off.
- cronix 5y ago
  Yes, AFAIK the piles didn't go all the way down to solid bedrock and San Francisco is basically built on a garbage dump covered over from previous devastating earth quakes, basically. They were improperly installed and if they had been the building would likely be fine. So, you're both right.
  - bitbckt 5y ago
    That area of the city is built on infill, but that is by no means true of most of the city’s area.
- beerandt 5y ago
  The problem in San Francisco is entirely different. It's on poorly designed building. Even if every building in San Francisco had that problem, it still wouldn't be relevant. The problem strata in New Orleans is the top 10-20' of soil. Mostly whatever's above the pumped-down, controlled, water table. Piles only need to go that deep to suffice, or more typically until they hit the first layer of sand, which is stable. Literally every slab house built in New Orleans is built in these, because before this, everything was on blocks so it could constantly be raised and leveled.
  - dylan604 5y ago
    >or more typically until they hit the first layer of sand, which is stable. I think this is the first time I have ever seen someone claim that a layer of sand is stable. But hey, NOLA is one of the craziest places, so sure, sand is stable there.
    - 5y ago
lostandbored 5y ago
Honestly, that is a great a reply. I especially agree that some dams on the Mississippi need to destroyed and have agriculture be moved away from the river, as the dead zone in Gulf of Mexico is caused by upstream agriculture states.
eloff 5y ago
> Worst case sea level rise estimates easily gives New Orleans 300+ more yrs, likely much longer, a time frame longer than the current age of the city. Your argument depends on this but you give neither numbers nor citations, so it's unsubstantiated and we have no idea how true it is. Numbers I've seen, that are bad, but not worst case are 6' by the end of the century and 20'-60' over longer timescales. I seriously doubt New Orleans will be just fine through that. Many coastal cities will have to move. It's not practical to wall in all of the coast to that extent. Many cities would end up being islands.
- pessimizer 5y ago
  > Your argument depends on this but you give neither numbers nor citations, so it's unsubstantiated and we have no idea how true it is. Unsubstantiated on this thread. I mean, you can look it up and find out if it's true yourself. It's also weird that you follow it up with numbers of your own, but also no references, so you must think that's alright to do.
  - eloff 5y ago
    You also don't know how substantiated my claims are, but at least with numbers you could look it up. Parent provided only an argument from authority. There is no easy way to falsify it. You'd have to do all the research from scratch.
    - eloff 5y ago
      People don't seem to understand what I'm saying. If the OP at least gives numbers you can compare them to easily looked up estimates and find out if they're reasonable or if you can ignore him in a couple minutes. Without that I'd have to search projected sea level rise, then read all about the elevation, vulnerability to storm surge, levees, flood risks, etc for New Orleans. It would take hours to know if the OP has a valid point or not. You might have to do that anyway, but at least if his numbers are bad you can shortcut the process and ignore him.
ahnick 5y ago
300+ years? And the biggest risk to the city is environmental activists and the EPA? You must be joking. The biggest risk is the fact that according to our best estimates by 2050 sea level rise will be another 1.5 feet in that area. (https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool) For an area that is already on average 7 feet below sea level. New Orleans topography is basically a bowl between Lake Pontchartrain and the Gulf of Mexico. Couple that with stronger and more frequent hurricanes and there will be few places left to live in New Orleans and the surrounding area. People who give other people a false sense of hope is what endangers lives and sets up future generations for devastation. If you really want to help people you need to break the cycle and subsidize relocation costs for those who currently live there that can't afford to move. All these mitigation efforts like restoring the natural coastal barriers may delay some flooding (so sure do it), but it will not prevent the inevitable and it is coming much sooner than 300+ years.
- beerandt 5y ago
  >For an area that is already on average 7 feet below sea level. There are areas as low as -22' msl. Maybe -25'. But that's irrelevant, because the edge of the bowl and protection is at a minimum elevation ~+20' msl and up, depending on adjustments for things like modeled wave height. Whereas New York's highest protection is currently something like +8', and isn't a closed loop. And what's the elevation of the deepest basement/ subway/ tunnel in NYC? Because I bet it's a lot lower than -22' or -25' msl.
  - noahtallen 5y ago
    I don’t think NYC is really a counterexample/gotcha to their argument. If the commenter is right that a 1.5ft rise in sea level will cause a lot of damage to New Orleans, surely that line of thinking applies to both places (and all places close to the sea).
    - beerandt 5y ago
      >a 1.5ft rise in sea level It won't, precisely because New Orleans already has many places below sea level. It's got a head start. It's spent billions of dollars over 100+ years making the outer boundaries water tight, and building the infrastructure to support all of that, including the ability to pump 100% of rainfall out. To New Orleans, the cost of any sea level rise has essentially already approached the marginal rate. No where else in the world, with the exception of probably the Netherlands, is better prepared for rising waters, whether it's storm surge or sea level rise. Everywhere else has to pretty much start from scratch.
goatsi 5y ago
How is sediment deposition supposed to counteract the subsidence of land that has anything built on it?
- beerandt 5y ago
  Outside of levee protections, structures are all on piles above the flood elevation, so floods literally go under the house. Inside levee protections, as the system currently exists, it doesn't, so houses have to have sand pumped under them occasionally to fill gaps left by subsidence. The house is on piles, so it remains in place.
tobmlt 5y ago
Hey thanks for a very interesting and thought provoking reply. I lived in NOLA for 10 years and long may it live! Spot on with the destruction of the marshlands - something so desperately needing reversal. I was just wondering if you could provide a citation for this: >>>Worst case sea level rise estimates easily gives New Orleans 300+ more yrs I hope so. I fear not. Talking to my friends in the city it feels like if ida had spooled up 1 day further out, it would have wiped the place off the map. I know it isn’t true, but man, the wetlands are so mostly water below town, the storm didn’t loose strength, the next time… etc. I hope ida was the second-order wake up call the city needed to survive a future cat 5 with 30+ foot storm surge.
- beerandt 5y ago
  The LA CPRA coastal master plan, combined with army corps of engineers studies on further improving the post-Katrina levees. I'm trying to find the levee recommendations, but Biden's takeover seems to have broken all my bookmarks in the ACOE website. Basically it's just the ipcc/ epa most-likely-worse case scenario with some local adjustments, combined with CPRA's master plan for surge reduction and (non-nola) coastal protection and barrier island rebuilding, combined with the Corps' recommended levee improvements. You end up with lessened storm surges and raised levees that can match sea-level rise to whatever hight is feasible for the look levees, and back-out the years from the projected rate of sea level rise. And if they do the wall across the Orleans land bridge (preventing storm surge at the Rigolets and chef's pass), it's actually a much higher number. But that plan is on the back burner for now.
  - tobmlt 5y ago
    Thanks for all the context!
Brybry 5y ago
We did also cut the intracoastal waterway through swamps/marshes for commercial purposes (including large scale cypress logging). It's real easy to see on google earth all the nice straight lines we cut all over the place. That must have an impact on saltwater intrusion and help facilitate coastal wetland loss.
ryan_lane 5y ago
A large amount of the marsh reduction is due to oil company activities. You're not wrong that we need to let the river shift, but that alone isn't going to save the coastline, and it's not the primary cause of the loss of the marshlands. Also, it should be noted that the largest lobby group against fresh water induction isn't environmental groups, but the commercial fishing industry. The second largest lobbying group against it is the recreational fishing community. Both of these groups have the support of environmental groups because fresh water induction would indeed kill a large percentage of anything living in that induction area, and those living things are part of the ecosystem that keeps the marshlands alive. I don't think OP is wrong in that a Harvey situation would be disastrous. A decent percentage of the pumps in the city are broken for most of the year, and without those pumps, a storm like Harvey would likely result in levels of flooding similar to the levees breaking.
- beerandt 5y ago
  Oil companies are responsible for the canals, but that only allowed salt water to intrude quicker after rain or floods. But it doesn't change the overall regime of becoming salt dominant. It just means maybe 40 freshwater days a year instead of 50 at s given location, but it doesn't change what's growing there. Additionally, marsh biological productivity has been directly tied to shoreline length. So a marsh with proper salinity levels and more shoreline will actually create more food, for more wildlife. I do believe that they ought to be held to the terms of their permits, which is typically to backfill anything not actively maintained or abandoned. And to prevent erosion beyond the limits of the permits. But it doesn't seem that's part of the negotiation. >fresh water induction would indeed kill a large percentage of anything living in that induction area, False- the locations already getting freshwater (not sediment) diversions and the natural breaks in the levees are the only healthy parts of the marsh right now. Go look at them on Google Earth. Mardi gras pass and the other natural breaks are the only places naturally building land outside of the Atchafalaya Delta. For the new sediment diversions: It's not going to kill anything-it's just going to push the brackish water out and the salt water further, for a limited number of weeks per year. The wildlife will move with it, as it always has. The commercial guys don't want to burn more gas to get to saltwater, and the oyster guys (the real money and lobby power) don't want conditions to change at their existing water bottom leases. >and those living things are part of the ecosystem that keeps the marshlands alive. No freshwater mixing with saltwater is the basis for the entire estuary systems. Without that, the photosynthesis doesn't happen in the freshwater flora, and the food chain starts there for the rest of the living things. >A decent percentage of the pumps in the city are broken for most of the year, Political problem with the city, not an environmental or engineering problem.
pbronez 5y ago
> As for global warming? Infrastructure, business and homes are amortized at 30yrs or less. Maybe up to 50yrs for very large civil projects. I don’t understand this comment. I assume you’re not talking about financial amortization. Do you mean the climate impact of new construction (such as 1 ton CO2 per 1 ton concrete) has some kind of sunset period?

pfisch 5y ago

It is and it isn't. His scenario won't happen but what will happen is fairly similar. No one is going to make large capital investments in a city that gets blown away all the time. Every time New Orleans takes a big hit like this people leave, and less money is put back into the city. The population of New Orleans was higher in 1980 than it is now. I am from New Orleans, and since Katrina the infrastructure has been getting worse, not better. There probably isn't going to be some big dramatic event that kills New Orleans. It will just keep shrinking and pulling in towards the French Quarter as it gets hit repeatedly by extreme weather events. It will just become smaller and more impoverished over time until it is maybe abandoned at some distant point in the future. It will be a death by inches.

beerandt 5y ago
Cities across the country will die much sooner from economic and political reasons than New Orleans will die from subsidence. (Although New Orleans is likely included in that first set as well, based on current leadership.) But we don't discourage economic development in those places. My amortization comment was perhaps not explicit enough, but as long as people think the city will last beyond amortization periods, future abandonment/inundation/end-of-days predictions are not a rational reason to preclude investment. Most businesses shoot for a payback period of 10 years or less. I expect you're right about slow death, but it won't be for climatic or geologic or hydraulic reasons. Fear of those reasons might contribute, but then we've gone full circle back to "alarmist BS".
- pfisch 5y ago
  You're being unrealistic about the reality of living in New Orleans and the level of capital investment in New Orleans vs Baton Rouge or other cities that aren't under constant threat of destruction. People just aren't going to come in and build nice shopping centers in New Orleans. It isn't happening and hasn't happened. Why would it when they could build in another city where it won't get destroyed and it will be more profitable? It is extremely stressful every year watching hurricanes and wondering if your house is going to be destroyed. Then when your house is destroyed it is no fun at all to be involved in gutting it and rebuilding it. On top of that no one is making investments in the city so it hardly has any good jobs. It isn't alarmist to recognize what is already happening. The climate is creating more extreme weather events that are undermining New Orleans. It doesn't need to be some fake "The Day After Tomorrow" style disaster that people can easily recognize. It is an insidious, slow, hollowing out of the city. How many water boil warnings have their been since Katrina? How often has electricity been inconsistent in the city? I can tell you it happens a lot more now than it did before Katrina, and it is going to be even worse after Ida.
  - jsight 5y ago
    How many homes were destroyed and will need to be rebuilt due to ida?

dylan604 5y ago

>Piles under everything from skyscrapers to personal homes penetrates the organic layers, so buildings don't subside even if the ground does. The sinking building in SF would like to differ with this. If a building is not built correctly, all bets are off.

cronix 5y ago
Yes, AFAIK the piles didn't go all the way down to solid bedrock and San Francisco is basically built on a garbage dump covered over from previous devastating earth quakes, basically. They were improperly installed and if they had been the building would likely be fine. So, you're both right.
- bitbckt 5y ago
  That area of the city is built on infill, but that is by no means true of most of the city’s area.
beerandt 5y ago
The problem in San Francisco is entirely different. It's on poorly designed building. Even if every building in San Francisco had that problem, it still wouldn't be relevant. The problem strata in New Orleans is the top 10-20' of soil. Mostly whatever's above the pumped-down, controlled, water table. Piles only need to go that deep to suffice, or more typically until they hit the first layer of sand, which is stable. Literally every slab house built in New Orleans is built in these, because before this, everything was on blocks so it could constantly be raised and leveled.
- dylan604 5y ago
  >or more typically until they hit the first layer of sand, which is stable. I think this is the first time I have ever seen someone claim that a layer of sand is stable. But hey, NOLA is one of the craziest places, so sure, sand is stable there.
  - 5y ago

lostandbored 5y ago

Honestly, that is a great a reply. I especially agree that some dams on the Mississippi need to destroyed and have agriculture be moved away from the river, as the dead zone in Gulf of Mexico is caused by upstream agriculture states.

eloff 5y ago

> Worst case sea level rise estimates easily gives New Orleans 300+ more yrs, likely much longer, a time frame longer than the current age of the city. Your argument depends on this but you give neither numbers nor citations, so it's unsubstantiated and we have no idea how true it is. Numbers I've seen, that are bad, but not worst case are 6' by the end of the century and 20'-60' over longer timescales. I seriously doubt New Orleans will be just fine through that. Many coastal cities will have to move. It's not practical to wall in all of the coast to that extent. Many cities would end up being islands.

pessimizer 5y ago
> Your argument depends on this but you give neither numbers nor citations, so it's unsubstantiated and we have no idea how true it is. Unsubstantiated on this thread. I mean, you can look it up and find out if it's true yourself. It's also weird that you follow it up with numbers of your own, but also no references, so you must think that's alright to do.
- eloff 5y ago
  You also don't know how substantiated my claims are, but at least with numbers you could look it up. Parent provided only an argument from authority. There is no easy way to falsify it. You'd have to do all the research from scratch.
  - eloff 5y ago
    People don't seem to understand what I'm saying. If the OP at least gives numbers you can compare them to easily looked up estimates and find out if they're reasonable or if you can ignore him in a couple minutes. Without that I'd have to search projected sea level rise, then read all about the elevation, vulnerability to storm surge, levees, flood risks, etc for New Orleans. It would take hours to know if the OP has a valid point or not. You might have to do that anyway, but at least if his numbers are bad you can shortcut the process and ignore him.

ahnick 5y ago

300+ years? And the biggest risk to the city is environmental activists and the EPA? You must be joking. The biggest risk is the fact that according to our best estimates by 2050 sea level rise will be another 1.5 feet in that area. (https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool) For an area that is already on average 7 feet below sea level. New Orleans topography is basically a bowl between Lake Pontchartrain and the Gulf of Mexico. Couple that with stronger and more frequent hurricanes and there will be few places left to live in New Orleans and the surrounding area. People who give other people a false sense of hope is what endangers lives and sets up future generations for devastation. If you really want to help people you need to break the cycle and subsidize relocation costs for those who currently live there that can't afford to move. All these mitigation efforts like restoring the natural coastal barriers may delay some flooding (so sure do it), but it will not prevent the inevitable and it is coming much sooner than 300+ years.

beerandt 5y ago
>For an area that is already on average 7 feet below sea level. There are areas as low as -22' msl. Maybe -25'. But that's irrelevant, because the edge of the bowl and protection is at a minimum elevation ~+20' msl and up, depending on adjustments for things like modeled wave height. Whereas New York's highest protection is currently something like +8', and isn't a closed loop. And what's the elevation of the deepest basement/ subway/ tunnel in NYC? Because I bet it's a lot lower than -22' or -25' msl.
- noahtallen 5y ago
  I don’t think NYC is really a counterexample/gotcha to their argument. If the commenter is right that a 1.5ft rise in sea level will cause a lot of damage to New Orleans, surely that line of thinking applies to both places (and all places close to the sea).
  - beerandt 5y ago
    >a 1.5ft rise in sea level It won't, precisely because New Orleans already has many places below sea level. It's got a head start. It's spent billions of dollars over 100+ years making the outer boundaries water tight, and building the infrastructure to support all of that, including the ability to pump 100% of rainfall out. To New Orleans, the cost of any sea level rise has essentially already approached the marginal rate. No where else in the world, with the exception of probably the Netherlands, is better prepared for rising waters, whether it's storm surge or sea level rise. Everywhere else has to pretty much start from scratch.

goatsi 5y ago

How is sediment deposition supposed to counteract the subsidence of land that has anything built on it?

beerandt 5y ago
Outside of levee protections, structures are all on piles above the flood elevation, so floods literally go under the house. Inside levee protections, as the system currently exists, it doesn't, so houses have to have sand pumped under them occasionally to fill gaps left by subsidence. The house is on piles, so it remains in place.

tobmlt 5y ago

Hey thanks for a very interesting and thought provoking reply. I lived in NOLA for 10 years and long may it live! Spot on with the destruction of the marshlands - something so desperately needing reversal. I was just wondering if you could provide a citation for this: >>>Worst case sea level rise estimates easily gives New Orleans 300+ more yrs I hope so. I fear not. Talking to my friends in the city it feels like if ida had spooled up 1 day further out, it would have wiped the place off the map. I know it isn’t true, but man, the wetlands are so mostly water below town, the storm didn’t loose strength, the next time… etc. I hope ida was the second-order wake up call the city needed to survive a future cat 5 with 30+ foot storm surge.

beerandt 5y ago
The LA CPRA coastal master plan, combined with army corps of engineers studies on further improving the post-Katrina levees. I'm trying to find the levee recommendations, but Biden's takeover seems to have broken all my bookmarks in the ACOE website. Basically it's just the ipcc/ epa most-likely-worse case scenario with some local adjustments, combined with CPRA's master plan for surge reduction and (non-nola) coastal protection and barrier island rebuilding, combined with the Corps' recommended levee improvements. You end up with lessened storm surges and raised levees that can match sea-level rise to whatever hight is feasible for the look levees, and back-out the years from the projected rate of sea level rise. And if they do the wall across the Orleans land bridge (preventing storm surge at the Rigolets and chef's pass), it's actually a much higher number. But that plan is on the back burner for now.
- tobmlt 5y ago
  Thanks for all the context!

Brybry 5y ago

We did also cut the intracoastal waterway through swamps/marshes for commercial purposes (including large scale cypress logging). It's real easy to see on google earth all the nice straight lines we cut all over the place. That must have an impact on saltwater intrusion and help facilitate coastal wetland loss.

ryan_lane 5y ago

A large amount of the marsh reduction is due to oil company activities. You're not wrong that we need to let the river shift, but that alone isn't going to save the coastline, and it's not the primary cause of the loss of the marshlands. Also, it should be noted that the largest lobby group against fresh water induction isn't environmental groups, but the commercial fishing industry. The second largest lobbying group against it is the recreational fishing community. Both of these groups have the support of environmental groups because fresh water induction would indeed kill a large percentage of anything living in that induction area, and those living things are part of the ecosystem that keeps the marshlands alive. I don't think OP is wrong in that a Harvey situation would be disastrous. A decent percentage of the pumps in the city are broken for most of the year, and without those pumps, a storm like Harvey would likely result in levels of flooding similar to the levees breaking.

beerandt 5y ago
Oil companies are responsible for the canals, but that only allowed salt water to intrude quicker after rain or floods. But it doesn't change the overall regime of becoming salt dominant. It just means maybe 40 freshwater days a year instead of 50 at s given location, but it doesn't change what's growing there. Additionally, marsh biological productivity has been directly tied to shoreline length. So a marsh with proper salinity levels and more shoreline will actually create more food, for more wildlife. I do believe that they ought to be held to the terms of their permits, which is typically to backfill anything not actively maintained or abandoned. And to prevent erosion beyond the limits of the permits. But it doesn't seem that's part of the negotiation. >fresh water induction would indeed kill a large percentage of anything living in that induction area, False- the locations already getting freshwater (not sediment) diversions and the natural breaks in the levees are the only healthy parts of the marsh right now. Go look at them on Google Earth. Mardi gras pass and the other natural breaks are the only places naturally building land outside of the Atchafalaya Delta. For the new sediment diversions: It's not going to kill anything-it's just going to push the brackish water out and the salt water further, for a limited number of weeks per year. The wildlife will move with it, as it always has. The commercial guys don't want to burn more gas to get to saltwater, and the oyster guys (the real money and lobby power) don't want conditions to change at their existing water bottom leases. >and those living things are part of the ecosystem that keeps the marshlands alive. No freshwater mixing with saltwater is the basis for the entire estuary systems. Without that, the photosynthesis doesn't happen in the freshwater flora, and the food chain starts there for the rest of the living things. >A decent percentage of the pumps in the city are broken for most of the year, Political problem with the city, not an environmental or engineering problem.

pbronez 5y ago

> As for global warming? Infrastructure, business and homes are amortized at 30yrs or less. Maybe up to 50yrs for very large civil projects. I don’t understand this comment. I assume you’re not talking about financial amortization. Do you mean the climate impact of new construction (such as 1 ton CO2 per 1 ton concrete) has some kind of sunset period?