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After a record-breaking winter snowfall season for the
continental Unites States and a plethora of spring season rainfall, overfull
reservoirs are bearing down on the human defenses of modern times. New
Orleans, a city built on a delta that has flooded and evolved several times
throughout the past 4,600 years, will be put to the test once again. Will the
fluvial transport, storm surges, and flood levels be kept at bay when the
seasonal spring freshet is at its maximum?
New Orleans stands to fight an uphill battle as the land
subsides (compacts, settles and sinks), where fluvial transport has been
blocked and the river-bed deposits shift the Mississippi River's gradient to
where it has been directed to flow. Every year, the probability that the
Mississippi will redirect itself increases. It will redirect itself when the
land has been flooded, either due to some type of storm surge or incidental
flooding plausible when coupled with seasonal high-flow volume from both heavy
rain and melting snow.
When this happens, the majority of the residing reservoir
blocked uphill will move towards a favorable course to the Gulf of Mexico,
possibly down the Atchafalaya River after
the Old River Flood Control Structure has been breached. This is one of the
first human-made structures that were built to control the Mississippi River.
When the river redirects itself,
concerns about flooding in New Orleans will only increase as the land further
subsides below sea level. Subsequent salt water intrusions will cause the loss
of wetlands and freshwater vegetation. In turn, this will increase the
probability that the coast will recede and be swept away.
The Atchafalaya River will flow.
Some portions of residential communities will be destroyed immediately, and the
battered, beaten yet very valuable port city will evolve and relocate. As has
been said more than once before, when will it happen and how bad will it be?
Resources:
http://www.wcc.nrcs.usda.gov/reports/UpdateReport.html;jsessionid=9EDA4BB5A0386935F8CC47081394132A?report=Alaska
http://www.tulane.edu/~bfleury/envirobio/enviroweb/FloodControl.htm
http://en.wikipedia.org/wiki/File:Mississippi_Delta_Lobes.jpg
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Re: <b>Freshet 2011: Target - The Big Easy</b>
