Damn, I was hoping that California would go first.
----- Original Message -----
From: "Mike Laborde" <[EMAIL PROTECTED]>
To: "RollTideFan - University of Alabama Athletics Discussion List"
<RTF@rolltidefan.net>
Sent: Monday, June 06, 2005 9:29 PM
Subject: [RollTideFan] YAY! We won't have to worry...
about LSU too much longer!
http://www.chron.com/cs/CDA/printstory.mpl/topstory/3210967
June 5, 2005, 6:28PM
IS TEXAS NEXT?
By ERIC BERGER
Copyright 2005 Houston Chronicle
By century's end, much of southern Louisiana may sink into the Gulf of
Mexico.
The Texas coastline, including Galveston, could soon follow.
That's the sobering - and controversial - conclusion of a new report
published
by the National Oceanic and Atmospheric Administration that finds the
northern
Gulf of Mexico is sinking much faster than geologists thought.
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.
And although a number of local officials disagree with the report's
conclusions
about Texas, here's a scary thought: Similar forces could well be at work
just a
few miles south of Houston.
"Subsidence doesn't stop at the Texas border," said Roy Dokka, a co-author
of
the NOAA report and a Louisiana State University geologist.
A colleague of Dokka's in Houston, the editor of the Houston Geological
Society
Bulletin, is more blunt in his assessment of the report. "Galveston," says
geologist Arthur Berman, "is history."
Flooding a major threat
The report already has ignited debate in Louisiana. If that state's coast
continues to sink, its multibillion-dollar plan to protect coastal cities
and
wetlands from flooding has targeted the wrong problem, erosion. Every
building
on land certified as safe from flooding may, in fact, be in danger if
Louisiana's benchmarks are flawed. And levees thought to protect New Orleans
from a Category 3 hurricane might fail even if a moderate Category 2 storm
struck the Big Easy.
Texas could have similar problems if its benchmark elevations are flawed.
The
National Hurricane Center bases its storm-surge models on benchmarks, as do
emergency planners trying to determine when key evacuation routes might
flood.
Houston felt the problem acutely during Tropical Storm Allison when
benchmarks
indicated that certain areas, such as some Texas Medical Center buildings,
should not have flooded even in the torrent of rain produced by that storm.
"We know that a lot of benchmarks in Texas are inaccurate," said Gary
Jeffress,
a mapping specialist at Texas A&M University-Corpus Christi.
Shifting land
Subsidence - the sinking or settling of land - comes in two basic forms. One
is
man-made, caused by groundwater pumping or oil and gas extraction. The
other,
which Dokka says is causing nearly all of the problems along Louisiana's
coast,
is natural, or geologic, subsidence.
Houston has grappled with man-made subsidence for the past 30 years with
help
from the Harris-Galveston Coastal Subsidence District, which has spent about
$10
million studying and measuring the problem.
As a result of this research, the Houston region has undergone a
multibillion-dollar conversion from ground wells to surface water for its
consumer and industrial needs. In the next decade or so, north and west
Harris
County will spend as much as $3 billion more for a similar conversion.
Ron Neighbors, general manager of the subsidence district, said he thinks
this
conversion has largely solved the area's subsidence problems. He attributes
little of the region's sinking to geologic subsidence and doesn't think the
area's coastal regions may be sinking as much as 4 or 5 feet a century.
"We realize there is some amount of natural subsidence that will occur over
time," Neighbors said. "But we believe that to be about three quarters of a
foot
per century."
If he has little confidence in the report by Dokka, Neighbors has even less
in
the scientist himself. Neighbors said the Louisiana geologist has incentive
to
cause fear.
"You don't get any grants if you say everything is OK," Neighbors said.
Berman said that, although conclusions drawn by Dokka's report are
controversial, they were checked by NOAA for 18 months and wouldn't have
been
published if they were bogus. The controversy comes, he says, because the
findings challenge existing models.
Every geologist agrees that three main factors contribute to coast loss:
rising
sea levels, coastal erosion and subsidence. What Dokka and his supporters
suggest is that the role of natural subsidence is nearly as important, or
even
more important, than man-made subsidence. And the problem for coastal
planners
is that, unlike with man-made subsidence, there's nothing that can be done
to
stop natural subsidence.
Forces of nature
Dokka and others think geologic forces during millions of years are acting
to
sink the Gulf Coast. The Texas coast rests upon a mobile layer of shale
about
20,000 feet below ground. But because lots of water is mixed in with the
shale,
it cannot be fully compacted into rock, so it behaves something like
toothpaste,
geologists say.
A second observation is that several rivers, principally the Mississippi but
also the Colorado, Brazos and many others, drain into the Gulf of Mexico,
bringing untold tons of sediment over millions of years.
"You're draining almost the entire North American continent into the Gulf,"
Berman said. "The cumulative weight of that is immense."
So immense, in fact, that the Gulf of Mexico is pushing down on the Earth's
crust, making an indent. For coastal regions along the Gulf, it's like being
at
the edge of a trampoline with a bowling ball weighing down the center: The
natural inclination is to slide toward the center. The toothpastelike shale
layer facilitates the slide, Berman said. Geologists call it gravity
gliding.
Roberto Gutierrez, a geophysicist at the University of Texas at Austin's
Bureau
of Economic Geology, said Dokka's results were not unexpected among the
geosciences community. "The Earth is a dynamic place," he said.
State's efforts fledgling
But even after the Dokka study, the central question - What is the dominant
factor driving coastal land loss in Texas? - remains unanswered, he said.
Like
other geoscientists contacted for this article, Gutierrez said there simply
isn't enough data to know how natural subsidence is affecting Texas.
Texas' General Land Office estimates that the state loses about 235 acres of
Texas Gulf shoreline each year. Like Louisiana, the state's Coastal Texas
2020
program has focused on coastal erosion.
The coastal program has received funding only since 1999 and has just begun
to
study the issues, said Lorrie Council, a team leader. During meetings with
coastal landowners and public officials, she said, they pointed to beach
loss
from erosion, primarily when strong storms cause big waves and wash sand out
to
sea, as the biggest problem.
The state recently created a committee to look at subsidence as a factor,
she
said.
"It's something we're aware of, but we don't have enough information on it,
and
we're working actively to get it," she said.
The information may well come from Jeffress, the geographer at Texas
A&M-Corpus
Christi. Because of efforts by U.S. Sen. Kay Bailey Hutchison, Jeffress says
he
will receive $665,000 to modernize the height of benchmarks along the Texas
coast. He hopes the grant will be renewed annually.
Expensive work
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.
One of Jeffress' first tasks, he says, will be checking the seawall road in
Galveston and the Gulf Freeway for low-lying spots that could serve as choke
points during an evacuation.
He said he has no doubt that many of the existing benchmarks used by highway
planners are incorrect. And although it's not his job to interpret why, he
says
he thinks natural subsidence must play some role.
"I think there's a general trend here," he said. "Considering how many
people
live along the coast, and how close they live to the water, this could be a
problem in the future."
Area well documented
But Neighbors says subsidence in Harris and Galveston counties is the most
well
studied in the country. Height modernization of benchmarks began here in the
mid-1980s, he said, and when communities, including those in Louisiana,
wanted
to learn how to improve their elevation measurements, they come here.
The subsidence district's records, he said, indicate that subsidence has
slowed
or even halted in Harris and Galveston county areas where groundwater
pumping
has ceased.
To justify billions of dollars in conversion from groundwater to surface
water,
he said, the science had to be sound.
Simply put, Neighbors said, if natural subsidence were a problem here he
would
know about it. Then he paused, in thought. Geology, with all of the Earth's
chaotic, unpredictable and violent processes, is not a science of absolutes.
"I'm not going to say that we've learned it all," he added. "We don't know
everything. But I don't think we're going to fall into the sea anytime
soon."
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