How Does a Beach Erode and Why Does it Happen?
FORT MYERS - Almost every beach experiences some level of erosion, but some erode more than others. Why does it happen and how does it happen?
There are actually two different ways a wide, sandy beach can turn into a narrow, eroded beach. The first type of erosion is the natural response of a beach to harsh winter storms and calm summer weather.
"During winter storms, energetic waves scour sand from the visible part of the beach, transporting it to an offshore sandbar. The bar then dissipates the wave energy and protects the beach from further damage," explained Nicole Elko, Ph.D., coastal coordinator for Pinellas County, Fla. "This results in a flatter, narrower beach than in the summertime."
Over time, as the calm spring and summer weather returns, the waves get smaller and slowly return the sand from the sandbar back onto the visible portion of the beach. This process is called accretion.
"An unscientific explanation is this: Beaches are smart," Elko said. "They move sand out to a sandbar in the wintertime to protect themselves; then, when the conditions are gentler, the sand is transported back onshore."
The second type of beach erosion is more serious. "Some beaches do not have enough sand available to respond naturally to storms," she explained. This sand starvation can be due to natural causes, such as sea level rise, or blocking of natural sand movement by impediments such as seawalls, jetties, inlets, harbors or dams.
When there is not enough sand on a beach, it is not able to recover fully after a storm. "That's where beach nourishment can play a vital role in the health of a beach," Elko concluded. Beach nourishment is the process of adding sand to an eroded beach to restore its protection and recreation benefits.
"We are currently managing three federal and two local beach restoration projects here in Pinellas County and have seen firsthand how a well-managed beach project can successfully slow down beach erosion," Elko said. "We've been very pleased with the results." of the largest possible number of people in accordance with the ideals of a democratic nation. For additional information about ASBPA, please visit www.asbpa.org.
This information is provided by the American Shore & Beach Preservation Association.
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