After a $14-Billion Upgrade, New Orleans' Levees Are Sinking
- PeteRasche
- Cornerstone
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Re: After a $14-Billion Upgrade, New Orleans' Levees Are Sin
Maybe we're going about things the wrong way
Futuristic, floating city can withstand Category 5 hurricanes
Futuristic, floating city can withstand Category 5 hurricanes
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- Roller
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Re: After a $14-Billion Upgrade, New Orleans' Levees Are Sin
Needing lifts to the levees (and "lifts" is by no means a "misleading" term to Civil Engineers) is nothing new. The Mississippi River levees have been getting constant lifts along their entire length ever since they were first built. It's part of the design considerations.
Most people do not realize that the Mississippi River is now flowing along the top of a ridge that is quite a bit higher than it was before the levees were built. That's because the river bottom rises over time, despite all the dredging we can do, and the levees are raised to maintain flow capacity. Over the past century, the river has actually been raised several feet.
If the bridges survived a few thousand years, they would be inundated, but the land behind the levees would still be dry, assuming that the land was filled ("lifted," as it were) to keep pace with the amount of head the levees could stand.
But land subsidence is a fact of life in South Louisiana, and if you're gonna build there, it needs to be accepted and taken into account.
Most people do not realize that the Mississippi River is now flowing along the top of a ridge that is quite a bit higher than it was before the levees were built. That's because the river bottom rises over time, despite all the dredging we can do, and the levees are raised to maintain flow capacity. Over the past century, the river has actually been raised several feet.
If the bridges survived a few thousand years, they would be inundated, but the land behind the levees would still be dry, assuming that the land was filled ("lifted," as it were) to keep pace with the amount of head the levees could stand.
But land subsidence is a fact of life in South Louisiana, and if you're gonna build there, it needs to be accepted and taken into account.