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#07-09 January 8, 2007

Cooper River Bridge materials enhance marine artificial reefs

Marine artificial reef habitats have been refurbished and new marine life is thriving, thanks to generous contributions from the Cooper River Bridges.

South Carolina’s marine artificial reefs, managed by the S.C. Department of Natural Resources (DNR), received more than 240,000 tons of concrete and steel rubble, materials that were once a part of the Grace Memorial and Silas N. Pearman Bridges. Twelve reef sites, from Edisto to McClellanville, each received at least three barge loads of concrete and steel material from the former bridges. See video from previous reef deployment>>>
           
The reef donations from the bridges were determined to be an economically valuable and environmentally beneficial way to reuse the rubble material. The environmental impacts of reefReef enhancement refurbishing with this type of material are numerous, and according to Bob Martore, DNR Artificial Reef Program coordinator, “The structures help to create habitat and bolster important fish communities. In fact, colonization on the new reef material begins within days of deployment.” In a report prepared by HDR Engineering Inc. of the Carolinas for the S.C. Department of Transportation to assess the demolition project impact, it was stated that in 1990 alone, recreational boaters fishing on artificial reefs had an estimated impact of $17 million on the state’s economy, and recreational diving had an estimated impact of more than $339,000.
           
The year-long artificial reef enhancement project required the efforts of many, including the Massachusetts based demolition company tasked with dismantling the bridges, Jay Cashman Inc. Constructors/Testa Corp. The idea to replenish nearby artificial reefs with the bridge material “worked really well for the joint venture of Jay Cashman Inc./Testa Corp,” said Kenneth Canty, project engineer for the Cooper River Bridge Demolition Project. The contractors, after loading deck and hopper barges with bridge material at the Charleston Navy Base, received artificial reef coordinates from the DNR and placed the structure on existing reef sites. Looking back on the project’s accomplishments, Canty observed that, “We enjoyed the benefits of an excellent working relationship with the DNR. By communicating and working closely with the DNR, the reef deployment was a success for the Cooper River Bridge Demolition Project.”

South Carolina’s marine artificial reefs are constructed for several important reasons. Primarily, they are useful for providing additional productive locations for recreational saltwater anglers. Additionally, artificial reefs create hard bottom habitat areas for marine species, areas that are limited off the coast of South Carolina. Martore noted that while natural reefs are comprised of limestone rock, artificial reefs enhanced with concrete rubble, characteristic of the Cooper River Bridges material, are closely aligned with natural fish habitat composition. In fact, “Diving on the reefs that have received enhancements from the Cooper River Bridges,” according to Martore, “has already offered a glimpse of thriving fish communities.” The habitat enhancement from artificial reef materials attracts intensive invertebrate communities and fish assemblages.

How do these artificial reefs work in attracting marine life? The three dimensional habitat is rapidly colonized, initially with sessile organisms including algae, barnacles, coral and sponges. This cover becomes the foundation for the reef community and serves as the basis of the food chain. The structures shelter, feed and offer spawning grounds for a host of marine species. Crabs, shrimp, starfish, sea urchins, amphipods, mollusks and juvenile fish are attracted to the reef and in turn, offer a luring opportunity for larger fish important to the recreational fishing industry.
           
The DNR Marine Artificial Reef Program currently maintains 45 reef sites in estuarine, coastal and offshore waters. The sites are marked with yellow Nun buoys to assist boaters in locating and using the reefs.

Marine artificial reefs that have received supplements from the Grace Memorial and Silas N. Pearman Bridges include: Edisto 40’ Reef; Edisto 60’ Reef; Edisto Offshore Reef; North Edisto Nearshore Reef; Kiawah Reef; Lowcountry Anglers Reef; Charleston 60’ Reef; Charleston Nearshore Reef; Capers Reef; Y-73 Reef; Comanche Reef; and Coastal Conservation Association McClellanville Reef.
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