Q. On the Wrightsville Beach side of Masonboro Inlet the rock wall does not start for a few hundred feet. There is a wood/metal bulkhead that spans the gap between the beach and rocks. What is the design purpose of that? On the Masonboro Island side the rock wall is solid from the sound all the way out to the inlet entrance out in the ocean.
A. A jetty is typically a manmade structure designed to influence currents and tides or to protect beaches or harbors from waves.
According to Bob Dennis, a Coastal Engineer with the Army Corp of Engineers, “The wood/metal bulkhead that spans the gap from the beach to the rock jetty is called a Weir Jetty. The general purpose of a jetty is to keep sand from moving into the inlet. However, sand can build up on one side and corrode the other. A Weir Jetty system is built to allow sand to pass over, which is then deposited into a deposition basin and eventually dredged out.”
The idea for this type of jetty was discovered in Hillsboro, south Florida, by observing a natural rock formation that allowed sand to pass over. Masonboro Weir Jetty was the first jetty of this type built in the United States back in 1966.
Date posted: September 12, 2012
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