pipes lay across a partially constructed island of light-colored sand. the island is near shore, but surrounded by water.

Coasts

One Good Turn Deserves Another

A dredging operation provides material to restore Crab Bank, an important seabird sanctuary in Charleston Harbor.

Crab Bank, an island in Charleston Harbor, South Carolina, has been a critical nesting spot and refuge for birds for decades. But years of erosion, and then a brutal storm and high tide in 2018, washed much of island away, and the area went from supporting 5,000 nests yearly to zero. Local conservation groups, including Audubon South Carolina, have discussed the need to restore Crab Bank for years, and in 2021 it finally happened. After a very busy fall in Charleston Harbor, this spring shorebirds will find 32-acres of brand new island around Crab Bank.

Luck or chance were in Crab Bank’s favor when it came to its restoration, because when the island needed new sediment the most, the Charleston Harbor Deepening Project was also launched just a couple of miles away. That project, which will increase the depth of Charleston Harbor from 45 feet to 52 feet, has already removed nearly 40 million cubic yards of sediment. And what better place to put some of that dredged sediment than on a nearby island desperate for it?  

The South Carolina Department of Natural Resources (SCDNR) first spotted the opportunity to restore Crab Bank using dredged sediment, says Nolan Schillerstrom, the coastal program associate at Audubon South Carolina. “It wasn’t until 2017 that the Army Corps of Engineers opened up a comment period for the beneficial use of dredged material as part of the Charleston Harbor Deepening project. They had three different [potential] options for the beneficial use of that trench material. One of those options was Crab Bank.”

Audubon South Carolina joined partners like Coastal Conservation League, Coastal Expeditions Foundation, and SCDNR to make the project successful. According to Angelina Eisenhauer, interim executive director of Audubon South Carolina, one of Audubon's main roles in the effort was securing the funding.

“We submitted an application to have the whole project and island considered as a pilot program for the U.S Army Corps of Engineers Beneficial Use of Dredge Materials program,” says Eisenhauer. “We undertook a fundraising campaign, and we submitted an application for a coastal resilience National Fish and Wildlife Foundation grant.” As a result of those efforts, Audubon South Carolina received $700,000 for Crab Bank from the National Coastal Resilience Fund.

As Audubon South Carolina and its partners continued to raise funds for the project, they also had to figure out the best way to restore and stabilize Crab Bank with natural infrastructure to ensure its longevity. This is another spot where fortune smiled upon the project: the material dredged from the harbor was good for nesting and it was compatible with the existing island, in part because the original Crab Bank was built on dredge spoils from the 1950s.

“One of the most amazing things about it was that the dredge material was suitable for nesting. The birds aren't too picky, but sometimes it is too toxic or not the right consistency,” says Schillerstrom. “It was just a really rare and awesome opportunity, a perfect scenario that the available sediment had what this island needed.” 

Over the course of eight weeks, the deepening project added 600,000 cubic yards of dredged material to the eroded island, increasing its area from less than half an acre to 32 acres. Construction ended in late 2021. The natural vegetation that will grow on the island will help stabilize the island long-term, but Schillerstrom says there are no other stabilization plans until they observe how the first nesting season looks. 

“We certainly have it on our minds that it might be necessary to either add more sediment many years down the road or do something to give the island a better shot at staying around for longer,” he adds. 

And though this restoration project may be coming to a close, Schillerstrom says that this is just one step in helping coastal birds. Going forward, people will not be able to land on the island during nesting season and shorebird monitors will keep an eye out for any human or predator incusions, all in effort for the birds to have a productive nesting season once again at Crab Bank.

“Human disturbance is one of the largest threats to coastal birds in South Carolina, and our Shorebirds Stewardship program is one of the best ways to get involved and volunteer to help,” Schillerstrom says. “If you can't volunteer, please consider donating to the program and help reduce the negative impacts of human disturbance to our nesting and resting coastal bird populations”

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