Rising Sea Level

Rising Sea Level

Rising sea levels have been disturbing geographers and geologists for
some time now. Scientists are constantly trying to prevent the effects
rising waters are causing, which mainly includes beach and island erosion.

So far, their attempts with man-made development on beaches along the eastern
coast of America have only made things worse.

"Up and down the U.S. coast, public money is subsidizing private property
on islands made of sand, the stuff on which, as the Bible says, only fools
build" (Ackerman 7). In recent years there has been a trend towards living
on the barrier islands of America's Atlantic Coast. High rise condominiums,
numerous shops, and several businesses have been built to sustain large
populations on these islands and continue to be built. As a result, this
vital chain of islands that lies between the ocean and the mainland are
at risk.

While interfering with the natural configuration of these islands, human
construction has advanced the rate of beach erosion, thus leaving the mainland
with no barriers during times of high surf. This effect has also led to
costly, unnatural ways to preserve the barrier islands. Saving these islands
in their natural state by curbing human encroachment will both protect
mainland populations from high surf and save a considerable amount of federal
money. The barrier islands are a chain of islands, stretching from New

York to southern Texas, that have served as a critical barrier from the

Atlantic Ocean for well over the past 4,500 years (Ackerman 23).

These islands however are not as stable as those who live on them would
like it to be. Beaches, and in fact whole islands, are constantly eroded
as they are subjected to varying winds, currents and changing sea levels.

Along Florida's East Coast, roughly 368 miles, the average shoreline change
is retreating 22cm per year. Under natural conditions, native vegetation
and shifting sands constantly replace or withhold sand on the islands (16).

Unfortunately for the inhabitants of the barrier islands, this is a geological
behavior which can only continue if the islands remain in a natural state.

In recent years humans on these shorelines and islands have been responding
to the naturally changing conditions, through the use of man made structures
such as seawalls, groins, and sand replenishment, in an effort to save
beachfront property from erosion.

Obstructing the natural shifts of the islands, says Orrin Pilkey of

Duke University who has studied these islands for thirty years, will cause
them to, "be lost forever" (16-17). Attempting to hold beaches in place
with the use of seawalls, groins, and sand replenishment may seem like
a good solution in theory, but in practice they probe ineffective. One
of the most common methods of attempting to hold barrier island beaches
in place is through the use of sea walls, which are costly and ineffective.

Seawalls are typically cement walls constructed parallel to the seashore
in an effort to block waves from coming over the beach and into property.

However, seawalls tend to withhold sand behind the wall during times of
high surf and the natural tendency of the beach to respond to waves is
disturbed (Kaufman 207).

The structures commonly fail from undermining or erosion by waves breaking
over their tops. Under normal conditions sand would be spread out by outgoing
currents, which in turn would lower the slope of the beach and cause the
waves to break gradually. With seawalls in place, sand remains stationary
while waves erode the beach as wave energy is deflected against sand not
protected by the seawall (208). In addition to advancing the erosion rate
of the sand and inhibiting the beaches' natural tendencies, seawalls have
become quite costly to maintain. For example, in New York $120 million
was paid by the federal government to sustain and replenish seawall installations
as of 1996, and repairs continue to be made (Dixon 231). Clearly, this
method is both costly and ineffective. Another commonly used method of
stopping erosion is the placement of groins, which are also ineffective.

Groins are pilings of rocks that extend into the ocean and perpendicular
to the shore. Like seawalls, the primary purpose of a groin is to trap
sand, but in longshore currents rather than sand deposits already on the
beach.

Contrary to their intended purpose, these structures trap sand on the
side facing a longshore current and leave the opposite side without sand
(Kaufman 207). Over time, the side not facing longshore currents erodes
and the initial problem reoccurs. Once again, after the unsuccessful use
of groins, money and resources must be spent to restore the beach. A recent
method of stopping erosion, and perhaps the most expensive, is that