On Mon, 25 Jun 2012 09:58:36 -0500, David Hartung <
da...@hotmaiil.com>
wrote:
In the Norfolk area, land subsidence is a problem but sea level rise
is major contributor. Reason is Norfolk is at juncition of several
rivers that are tributaries of Chesapeake Bay and the Atlantic Ocean.
As sea levels rise, water backs up into the tributaries thereby
hitting the Norfolk area with a double whammy -- not only is the sea
level rising but rivers are not draining.
-- quote
The sea level of the eastern coast of the United States is
accelerating at a much faster rate than the country’s other coasts due
to global warming, claim researchers from the U.S. Geological Survey
(USGS).
According to Damian Carrington, a reporter with the UK newspaper The
Guardian, the sea level rise of the “densely populated” Atlantic coast
from Cape Hatteras, North Carolina to Boston, Massachusetts is
increasing at a rate three to four times faster than the rest of the
country’s coastal regions.
Likewise, the Associated Press (AP) said, the 600-mile area, which the
USGS researchers dub a “hot spot” because of the sea levels, have been
rising at a rate up to 400% faster than the global average.
Among the fastest-rising areas are Norfolk, Virginia, where the sea
level has increased approximately five inches since 1990, and
Philadelphia, which has seen a four-inch rise.
“Many people mistakenly think that the rate of sea level rise is the
same everywhere as glaciers and ice caps melt, increasing the volume
of ocean water, but other effects can be as large or larger than the
so-called ‘eustatic’ rise,” USGS Director Marcia McNutt said in a
statement. “As demonstrated in this study, regional oceanographic
contributions must be taken into account in planning for what happens
to coastal property.”
“Cities in the hotspot, like Norfolk, New York, and Boston already
experience damaging floods during relatively low intensity storms,”
added Dr. Asbury Sallenger, a USGS oceanographer and the head of the
study, which is the subject of a paper published in the journal Nature
Climate Change. “Ongoing accelerated sea level rise in the hotspot
will make coastal cities and surrounding areas increasingly vulnerable
to flooding by adding to the height that storm surge and breaking
waves reach on the coast.”
While Sallenger told Carrington that this hotspot affect had
previously been predicted through computer modeling, the USGS study is
the first to use real data to prove that the sea-level acceleration is
currently occurring and that scientists can currently detect and
monitor it.
The cause, he said, is the warming of dense Arctic water, causing it
to sink more slowly and leveling out the so-called “slope” from the
fastest-moving water in the mid-Atlantic to the east coast of America.
As a result, the sea level in that location increases, and could
ultimately add as much as 30% to the global sea level rise.
“We came up with a very clear correlation between the acceleration of
sea level rise and rising temperature in the hotspot area. That
suggests to me that as long as temperature continues to rise the
hotspot will continue to grow,” Sallenger told the Guardian on Sunday.
Source: redOrbit (
http://s.tt/1fMcK)
-- end quote
-- quote
http://www.nytimes.com/2010/11/26/science/earth/26norfolk.html
NORFOLK, Va. — In this section of the Larchmont neighborhood, built in
a sharp “u” around a bay off the Lafayette River, residents pay close
attention to the lunar calendar, much as other suburbanites might
attend to the daily flow of commuter traffic.
If the moon is going to be full the night before Hazel Peck needs her
car, for example, she parks it on a parallel block, away from the
river. The next morning, she walks through a neighbor’s backyard to
avoid the two-to-three-foot-deep puddle that routinely accumulates on
her street after high tides.
For Ms. Peck and her neighbors, it is the only way to live with the
encroaching sea.
As sea levels rise, tidal flooding is increasingly disrupting life
here and all along the East Coast, a development many climate
scientists link to global warming.
But Norfolk is worse off. Situated just west of the mouth of
Chesapeake Bay, it is bordered on three sides by water, including
several rivers, like the Lafayette, that are actually long tidal
streams that feed into the bay and eventually the ocean.
Like many other cities, Norfolk was built on filled-in marsh. Now that
fill is settling and compacting. In addition, the city is in an area
where significant natural sinking of land is occurring. The result is
that Norfolk has experienced the highest relative increase in sea
level on the East Coast — 14.5 inches since 1930, according to
readings by the Sewells Point naval station here.
Climate change is a subject of friction in Virginia. The state’s
attorney general, Ken T. Cuccinelli II, is trying to prove that a
prominent climate scientist engaged in fraud when he was a researcher
at the University of Virginia. But the residents of coastal
neighborhoods here are less interested in the debate than in the
real-time consequences of a rise in sea level.
When Ms. Peck, now 75 and a caretaker to her husband, moved here 40
years ago, tidal flooding was an occasional hazard.
“Last month,” she said recently, “there were eight or nine days the
tide was so doggone high it was difficult to drive.”
Larchmont residents have relentlessly lobbied the city to address the
problem, and last summer it broke ground on a project to raise the
street around the “u” by 18 inches and to readjust the angle of the
storm drains so that when the river rises, the water does not back up
into the street. The city will also turn a park at the edge of the
river back into wetlands — it is now too saline for lawn grass to grow
anyway. The cost for the work on this one short stretch is $1.25
million.
The expensive reclamation project is popular in Larchmont, but it is
already drawing critics who argue that cities just cannot handle
flooding in such a one-off fashion. To William Stiles, executive
director of Wetlands Watch, a local conservation group, the project is
well meaning but absurd. Mr. Stiles points out that the Federal
Emergency Management Agency has already spent $144,000 in recent years
to raise each of six houses on the block.
At this pace of spending, he argues, there is no way taxpayers will
recoup their investment.
“If sea level is a constant, your coastal infrastructure is your most
valuable real estate, and it makes sense to invest in it,” Mr. Stiles
said, “but with sea level rising, it becomes a money pit.”
Many Norfolk residents hope their problems will serve as a warning.
“We are the front lines of climate change,” said Jim Schultz, a
science and technology writer who lives on Richmond Crescent near Ms.
Peck. “No one who has a house here is a skeptic.”
Politics aside, the city of Norfolk is tackling the sea-rise problem
head on. In August, the Public Works Department briefed the City
Council on the seriousness of the situation, and Mayor Paul D. Fraim
has acknowledged that if the sea continues rising, the city might
actually have to create “retreat” zones.
Kristen Lentz, the acting director of public works, prefers to think
of these contingency plans as new zoning opportunities.
“If we plan land use in a way that understands certain areas are prone
to flooding,” Ms. Lentz said, “we can put parks in those areas. It
would make the areas adjacent to the coast available to more people.
It could be a win-win for the environment and community at large and
makes smart use of our coastline.”
Ms. Lentz believes that if Norfolk can manage the flooding well, it
will have a first-mover advantage and be able to market its expertise
to other communities as they face similar problems.
But she also acknowledges that for the businesses and homes entrenched
on the coast, such a step could be costly, and that the city has no
money yet to pay them to move.
In the short run, the city’s goal is just to pick its flood-mitigation
projects more strategically. “We need to look broadly and not just act
piecemeal,” Ms. Lentz said, referring to Larchmont.
To this end, Norfolk has hired the Dutch firm Fugro to evaluate
options like inflatable dams and storm-surge floodgates at the
entrances to waterways.
But to judge by the strong preference in Larchmont for action at any
cost, it may not be easy for the city to choose which neighborhoods
might be passed over for projects.
Neighborhood residents lobbied hard for the 18-inch lifting of their
roadway, even though they know it will offer not much protection from
storms, which are also becoming more frequent and fearsome. Many say
that housing values in the neighborhood have plummeted and that this
is the only way to stabilize them.
Others like Mr. Schultz support the construction, even though they
think the results will be very temporary indeed.
“The fact is that there is not enough engineering to go around to
mitigate the rising sea,” he said. “For us, it is the bitter reality
of trying to live in a world that is getting warmer and wetter.”
-- end quote