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Contact Information

Civil Works Project Management
69A Hagood Ave
Charleston, SC 29405
CESAC-PM@sac.usace.army.mil

Call the Charleston District - 866.329.8187

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Hurricane & Storm Damage Reduction

For thousands of years, the forces of wind, water, storms, sea level changes, and other natural processes have moved the sediments that shape and reshape our coastlines and beaches. These sediments, which range from fine, white sand to coarse gravel and cobblestones, continuously build up, or accrete, only to drift away, or erode, again and again over time in complex and sometimes unpredictable ways. Wind, tides, currents, and waves constantly keep sediment on the move to build up and wear down natural features such as bluffs, dunes, beaches, sand bars, and inlets. Under normal conditions, wind shapes the dry beach and its dunes while tides, currents, and waves shape the “wet” part of the beach.  It is natural for hurricanes and coastal storms – which move huge volumes of sediment through the system – to erode beaches.

Charleston District has been involved in coastal storm damage reduction since the 1980s. The goal of storm damage reduction projects is to reduce the amount of damage to homes, businesses and infrastructure casued by coastal erosion from storm events. There are many ways to provide coastal storm damage reduction – from breakwater installation to sea walls to beach nourishment.

Within South Carolina, Myrtle Beach and Folly Beach both have Federal Storm Damage Reduction projects in place that utilize beach nourishment as the mechanism for providing damage reduction. The Water Resources Development Act (WRDA) of 2007 authorized a project for the southern end of Pawleys Island. The District is currently in our last year of study for Edisto Island. In order for a beach area to be eligible for the Corps’ storm damage reduction program, it must provide public beach access every one half mile and provide for adequate parking to support the use of the public access areas.

The Basics of Beach Nourishment

The Basics of Beach Nourishment
The Basics of Beach Nourishment
Many months before the start date, engineers begin surveying the ocean floor off the coast to find which areas have the right sand consistencies and quality to be used on the beaches.
Before Nourishment
Before Nourishment
Prior to the nourishment project, the beach is not wide enough to provide adequate storm damage reduction to the structures and infrastructure adjacent to the beach.
After Nourishment
After Nourishment
After the sand has been pumped and shaped, the new beach is wide enough to reduce the potential damages from hurricanes and nor’easters. The wider beach is also a benefit to the community from a recreation and tourism standpoint.
Borrow Site
Borrow Site
Detailed sampling and testing of the offshore sediment is used to identify a large area with sands compatible with the natural beach.
Dredge
Dredge
These vessels are responsible for removing the sand from the borrow area and delivering the sand to the beach. The method for removing the sand from the seafloor varies depending on the type of vessel. A hopper dredge temporarily stores the sand within the vessel and pumps it to the beach later. A cutterhead suction dredge moves the sand directly from the borrow area to the beach through a long section of pipe.
Pump Out Station
Pump Out Station
These additional pumps are used to aid the dredge in delivering the sand and water slurry to the beach. Stations like these are used in conjunction with hopper dredges or when the distance to the beach is too great for the dredge vessel pumps alone.
GPS
GPS
Global Positioning Satellite data is used to aid the dredge in navigating to and from the borrow area and to specific locations within the borrow area.
Survey Equipment
Survey Equipment
Before and after surveys of the beach are taken using amphibious tripod (commonly called a CRAB).
Pipe
Pipe
Sections of pipe are stockpiled and added to the end of the line as needed as the nourishment construction moves down the beach.
Delivery
Delivery
The dredged sand is delivered to the beach as a mixture of water and sand called slurry. The slurry then travels through large pips to the desired location.
Bulldozers
Bulldozers
Bulldozers are used to shape the newly placed sand into the desired beach width after the slurry water drains back to the ocean and the sand is deposited.
Slurry
Slurry
The water and sand slurry exits the pipe and is contained by the temporary dikes long enough for the water to drain back into the ocean while the sand is deposited on the beach.