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BigPapaSmurf
SFN Die Hard
3192 Posts |
 Posted - 06/06/2005 : 10:50:24
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Edit: add link duh! http://www.chron.com/cs/CDA/printstory.mpl/topstory/3210967#
Very fascinating story, I knew they we're screwed but this could be very bad if any hurricane hits.
quote:
The report centers on the humble benchmark, a small metal disk bolted to the ground, that provides a standard elevation above sea level for land surveying and mapping as well as determining flood-prone areas.
But there's one problem with benchmarks: They don't give reliable elevation readings if they're sinking along with everything else.
That's what the geologists who wrote the NOAA report say is happening in Louisiana: The yardstick is broken. Instead of minimal geologic subsidence along most of the Louisiana coast, as previously thought, the state's entire coastal region is sinking at least 5 feet every century.
quote:
Using a mix of traditional surveying and the Global Positioning System, Jeffress said, he will work with private contractors to begin updating the network of benchmarks installed in Texas shortly after World War II.
It's not cheap. The basic premise of the work Dokka did in Louisiana, which Jeffress will emulate to some degree in Texas, is to start at some point well inland that rests on bedrock. For Dokka that meant the upper reaches of Louisiana. For Jeffress, it means Austin. Then, like traditional surveyors, they take level readings by sight all the way to the coast. It's a time-consuming, costly process, requiring about $1,500 per mile.
Couldnt they use triangulation with lasers bounced off the moon? Or is that too innaccurate.
For those who dont know New Orleanes is way below sea level and great walls hold back the sea, If flooded by a mid sized hurricane they will be under 20 feet of water and there are only 2 evac routes aways from the city. With this news the damage estimates could skyrocket, especially if the whole levy system is sinking with the region.
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"...things I have neither seen nor experienced nor heard tell of from anybody else; things, what is more, that do not in fact exist and could not ever exist at all. So my readers must not believe a word I say." -Lucian on his book True History
"...They accept such things on faith alone, without any evidence. So if a fraudulent and cunning person who knows how to take advantage of a situation comes among them, he can make himself rich in a short time." -Lucian critical of early Christians c.166 AD From his book, De Morte Peregrini |
Edited by - BigPapaSmurf on 06/06/2005 10:51:02
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Tim
SFN Regular
USA
775 Posts |
Posted - 06/13/2005 : 23:26:20 [Permalink]
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The linked report states that Louisiana's " multibillion-dollar plan to protect coastal cities and wetlands from flooding has targeted the wrong problem, erosion." This statement misses the point. The problems we have down here are subsidence, erosion and silting. Subsidence affects the entire southern portion of the state and is from natural causes. Erosion and silting are man made and have become problems in different localities.
Oil and gas producers along with misguided civil engineers began making the swamps and marshes more easily accessible to industry and communities better protected from flooding nearly a century ago. They built roads, canals, weirs and levies. They straightenned river accesses to the Gulf, built locks and flood gates and created massive spillways to protect the major cities. These efforts lead to the silting of the swamps above the bottom of the levy systems and rapid erosion of the grassy marshlands along the coastal regions.
I happen to live in the area where the swamps transition into the marshes at the base of the Atchafalaya spillway. The effects of these man made problems are apparent to all who've lived here for a long time. The effects of subsidence are much less apparent. The ground is mud and things sink over time. Most folks expect the ground to sink, but not neccessarily before rising sea levels caused by lobal warming flood us out anyway. I guess you could say we're screwed anyway you look at it.
The biggest short term problem with coastal erosion is the danger to cities and towns near the Gulf. New Orleans, for instance, has always faced the threat of a strong tidal surge being pushed into Lake Ponchatrain from the Southeast. New Orleans is a large bowl protected by levies. If the surge were to wash over the levy system from the lake the pumps would be useless and we'd have Lake New Orleans.
The new problem is the vast amount of erosion to the marshes south of the city. A hurricane can now easily push a storm surge straight up the exposed Mississippi River channels and wash across the river side levies. And, if you've ever been to the Crescent City you've seen the odd sight of watching a ship pass by on a river that's higher than the street you're standing on.
We're not worried though. We'll just hop in our boats and go mouche off of our friends in Arkansas. |
"We got an issue in America. Too many good docs are gettin' out of business. Too many OB/GYNs aren't able to practice their -- their love with women all across this country." Dubya in Poplar Bluff, Missouri, 9/6/2004
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skepticality
Skeptic Friend
USA
105 Posts |
Posted - 06/14/2005 : 09:00:37 [Permalink]
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Maybe they should just start a project now to dismantle the Quarter brick by brick and re-build it somewhere safe.  |
Derek Colanduno
host - skepticality
http://www.skepticality.com/ |
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BigPapaSmurf
SFN Die Hard
3192 Posts |
Posted - 06/14/2005 : 10:48:08 [Permalink]
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| It would probably be cheaper to do that in the long run. |
"...things I have neither seen nor experienced nor heard tell of from anybody else; things, what is more, that do not in fact exist and could not ever exist at all. So my readers must not believe a word I say." -Lucian on his book True History
"...They accept such things on faith alone, without any evidence. So if a fraudulent and cunning person who knows how to take advantage of a situation comes among them, he can make himself rich in a short time." -Lucian critical of early Christians c.166 AD From his book, De Morte Peregrini |
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skepticality
Skeptic Friend
USA
105 Posts |
Posted - 06/14/2005 : 21:19:29 [Permalink]
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Yea, I know...
I was half-kidding. It does seem like a serious discussion someone should be having. To lose something like the Quarter would be terrible. We have very little history like that remaining in the U.S. |
Derek Colanduno
host - skepticality
http://www.skepticality.com/ |
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