When the U.S. Army Corps of Engineers dredges sediment from the bottom of the Savannah river to maintain the depth of the shipping channel, all that material goes to a dredge material containment area (DCMA), commonly known as a dredge disposal area.
The Corps’ Savannah District maintains seven active DMCAs along the South Carolina side of the Savannah river, where dredged material is safely placed and managed.
One key aspect of managing DMCAs involves coordinating with the U.S. Fish and Wildlife Service. The Corps works with the Service to ensure disposal areas meet requirements to support bird nesting and wildlife habitat, such as maintaining a specified acreage of pond water.
In his first couple months as commander of the Savannah District, Col. Thomas Tickner visited several ongoing improvement projects and spoke with contractors at the disposal areas, Aug. 29.
Tickner visited DMCA 12A, which is the Corps’ largest disposal area for the Savannah harbor. He met with David Snodgrass, a quality control manager from Edgefield Construction, the prime contractor for the 12A improvement project.
The project includes the placement of 1.2 million cubic yards of dredge material to raise the dike, and the placement of 158,000 cubic yards of dredge material to place on inshore bird island, according to William Lane, Corps quality control inspector.
The bird island will be topped with an additional 30,000 cubic yards of coarse sand, relocated from dredge disposal area 14B. The sand will form a two-foot layer to provide adequate nesting habitat for birds, Lane said.
The 12A improvement project also includes repairing five weirs—structures that control the flow of water to the disposal area—and expanding walkways on the weirs. When complete, the 12A project will increase the Corps’ capacity to hold more dredged material from the Savannah Harbor. Construction began Sept. 2012 and is slated for completion in October 2013. The whole 12A interior spans 1,100 acres.
Ticker also visited DMCA 14A, where he met with Chad Brown, vice president of Ashridge Construction, the prime contractor for the 14A back dike raising project.
The project includes the placement of 198,000 cubic yards of dredge material to raise the back dike, plus an additional 40,000 cubic yards of sediment, according to Brown. It also includes the placement of 170,000 square yards of geotechnical fabric, which is layered under the dredge material to improve the structural stability of the dike. The team is also installing wick drains to help dissipate the groundwater.
Construction on the 14A back dike raising began in the spring of 2013 and is slated for completion in October.
Press Release, September 6, 2013