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Here's why the beach is eroding so fast

New research on erosion hot spots in St. Johns and Flagler counties

The sandbar east of the bridge over the Matanzas Inlet was completely removed after Hurricane Matthew. This dynamic coastline is being studied to see where the sand moved.
The sandbar east of the bridge over the Matanzas Inlet was completely removed after Hurricane Matthew. This dynamic coastline is being studied to see where the sand moved. (Assistant Professor Maitane Olabarrieta)

JACKSONVILLE, Fla. – The barrier islands never sit still. They are the mainlands protector from raging storms. The shore constantly tries to move inland and storms like Hurricane Matthew give the process a big boost. Now researchers are getting a better look at why parts of our coast lose sand quicker than other areas.

Erosion is actually a natural process along the coast and parts of it change more than others especially near the St. Johns and Flagler county boarder.

The Matanzas Inlet is unique in being one of the few inlets in Florida left natural without jetties and rarely dredged.

It sits at the center of a 36 mile long research area being studied by UF Civil and Coastal Engineering Department Assistant Professor Maitane Olabarrieta.

Dr. Olabarrista is predicting the impacts of removing sand from the Summer Haven river.  She is testing the idea that the new opening will increase the tidal flow and boost the flushing of water between the Atlantic and backwaters. 

She presented her researched to a packed crowd during an Evenings at Whitney Lecture series.

Sand's big push toward the mainland come when storms overwash the dunes pushing sand deposits into the backside of the barrier island.

The largest change occurred to Summer Haven River inlet between 2007-2009. Sand filled in the opening then Tropical Storm Fay in 2008 opened a breach in the barrier island. Several nor'easters later the inlet was closed again by 2009.

The combination of waves and tidal currents make the area especially dynamic. Currents rushing up to 3 and 4 mph swirl sand into suspension and shift sand southward.

Along St. Johns county, the average sand movement equals about 178 thousand pickup truckloads of sand (400,000 cubic yards) per year. Waves import 71,000 cubic yards of sand into the inlet.

Since this stretch of coast is so narrow, it will remain vulnerable to future storms more than other wider stretches along the barrier island.

 


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