Out in Jekyll Creek, work continues on the first dredging of that part of the Atlantic Intracoastal Waterway in more than 20 years. Out on a state Department of Natural Resources boat, the depth finder put the situation clear — at low tide, the depth is only around 5 feet.
If you’ve been out in the coastal wetlands — or walking on the beach only to find your leg knee-deep in the muck — you know some of the issues that come with dealing with pluff mud, the same muck that lines the channel.
“That’s why it fills in so bad here — that’s why this area is so problematic,” Paul Medders of the DNR’s Coastal Resources Division said Wednesday.
The plan, announced several weeks ago, is to take around 3 percent of the dredged material and spray it in thin layers over a nearby marsh in order to, hopefully, find a beneficial reuse for it. A pipeline extends from the Dredge Rockbridge, initially above the water, then submerged, and it comes back out of the water further north along the marsh bank.
“It’s going to come to a nozzle, and it sprays — it rainbows — in the air, and then as they’re doing that, at different points of time this week, they’re going to move it around to different places,” said Tyler Jones, communications specialist with CRD. “So, they’ll be between 3 inches and up to a foot in sediment that will be deposited here, and they should be done with that by Sunday.”
At 3 percent of the anticipated 200,000 cubic yards of mud removed from the channel, there should be around 6,000 cubic yards of the muck sprayed over a 5-acre layer surrounded by coconut-fiber logs. The idea is to provide more area at higher elevations for the growth of marsh grass.
There’s an area nearby that researchers are using as a control as they study the effects of the thin-layer technique.
The rest of the dredged material — around 194,000 cubic yards — is going into what’s known as the “deep hole” in the St. Simons Sound, around 800 feet south of the St. Simons Pier. It’s 60-80 feet deep and should be able to handle the Jekyll Creek sediment without causing problems to commercial or recreational vessels.
The effort is a $6 million project of the Army Corps of Engineers, which completed similar efforts in Louisiana, Maryland and New Jersey. The Chesapeake, Va., firm Cottrell Contracting is doing the work, and once it’s done, Jacksonville, Fla., business LG2 Environmental will monitor the movement of the sediment for up to two years.