DVIDS – News – Crab Bank Seabird Sanctuary: a landmark legacy


CHARLESTON, SC – A dredge, appropriately named Dredge Charleston, a daily crew of 53 workers and heavy earthmoving equipment worked around the clock for seven weeks to build a historic legacy of the Port’s Berth 45 Deepening Project of Charleston: The Restoration of Crab Bank. Crab Bank is a bird sanctuary located in Charleston Harbor near the shore of Old Mount Pleasant Village.

The project is a historic Post 45 legacy as the remainder of the $550 million deepening project is underwater and this massive investment is not visible to the public. In the case of Crab Bank, it has now become a feature of Charleston Harbor that can easily be seen and noticed from as far away as the Arthur Ravenel Jr. Bridge. The beneficial use of deepened channel materials has restored 32 acres of prime nesting sites, providing much-needed habitat for shorebirds and seabirds to increase their populations this spring and those to come.

Since placing the dredged materials on Crab Bank was not the least expensive method of placement, a non-Federal sponsor was needed to bring the concept to fruition. The South Carolina Department of Natural Resources (SCDNR) stepped in to fulfill this role and cost share the project. Without their commitment and our partnership, this sandy material would have ended up being sequestered in the ocean placement site and this seabird sanctuary lost for good.

Although the actual construction took only a few weeks, the idea originated years ago when the Post 45 Project Delivery Team was trying to identify potential projects to maximize the beneficial use of building materials. sandy dredging available from harbor deepening. Crab Bank has reached the top.

“Nine years ago Crab Bank was just a concept, three years ago the SCDNR stepped up its efforts to make it a reality, and this spring it is becoming a vital habitat and nesting ground for shorebirds. It is rare in the career of an engineer to see a project from concept to completion. Seeing this through to completion is very rewarding,” said Brian Williams, one of the project leads.

About 660,000 cubic yards, or 66,000 dump truck loads (a dump truck carries about 10 cubic yards), of materials created the crescent-shaped footprint, which can be seen from the Ravenel Bridge, the Alhambra Hall or other waterfront points on the harbor side of Mount Pleasant.

“The work is fascinating to see,” said project manager Jeff Livasy. “The hydraulic cutterhead suction dredge sucks material from the bottom of the channel, similar to a vacuum cleaner, and it is pumped onto the island through different types of pipes. Once the material is on the island, bulldozers begin shaping the material.

“It’s a little different from a beach restoration project,” said Chip Forbes, the field engineer for Norfolk Dredging Company, the contractor working for the district. “We usually have our guys smoothing out the sand perfectly, so it’s flat, even ground, but in this case the birds don’t want that. Different birds like different terrain, so it was fun to create something with bumps, bumps, and flat surfaces.

The island’s natural isolation protects birds and nests from predators. Over fifteen different species of birds have been spotted nesting on the island in previous years. The number of shorebirds and seabird nests are decreasing every year,” said Janet Thibault, wildlife biologist for the SCDNR. “It’s really important to have places where they can go. Around March or April the birds will return, find mates and build nests. So, I’m really excited to see this project come to fruition.

This one-time placement of materials could have a lifespan of up to 50 years, but in such a dynamic environment, we know the footprint will be smaller and change every year. Mother Nature will play a big role in the life of Crab Bank. The SCDNR will monitor the island each season with special cameras. This live webcam will also allow the public to see the inhabitants of the island in real time.

Visitors are not permitted on the island during the official nesting season which runs from March 15 to October 15 each year. During the remaining months, the island is only open below the high tide line and pets are prohibited.

With most of the island inaccessible, exploring the island by kayak or motorboat is a fun way to see the activity. We ask visitors to avoid generating boat wakes as this promotes erosion and we want to protect the island as much as possible.

USACE is proud to have partnered with the SCDNR in restoring this vital habitat and we look forward to “Welcome to the Birds” with a public event in April. Stay tuned to both agencies’ social media channels this spring for more information.

Date taken: 16.01.2022
Date posted: 16.01.2022 12:03
Story ID: 412963

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