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Artificial Reef System

Artificial Reefs Installed in Boston Harbor

The Central Artery/Tunnel Project has created a new home in Boston Harbor for blue mussels and other sea life.

In August, 1999 an artificial reef was placed in Boston Harbor as part of the CA/T Project's environmental mitigation program. The reef is the northernmost artificial reef system in the United States. It was designed to create a new ecosystem in the harbor, primarily as habitat for blue mussels and other shellfish. It also will become home for a variety of other sea creatures, such as lobsters, crabs, and finfish, which are attracted to the shelter of the reef structures, and to the algae and other food sources living on the reef complex.

Construction of the reef was required by environmental permits granted by the U.S. Army Corps of Engineers (ACOE) and by other federal and state agencies. The reef complex was required to provide a hard substrate with 88,000 square feet of surface area, as compensation for filling in 1.6 acres of blue mussel habitat in the harbor during the closing and capping of the former municipal landfill on Spectacle Island.

In collaboration with the National Marine Fisheries Service and the ACOE, Big Dig designers conducted ecological studies in the harbor, and they chose Sculpin Ledge Channel, between Spectacle Island and Long Island, as the reef site. The design included 17 terrace-type reef modules, each 20 feet square with five layers of panels, and six cobble/boulder patch reefs, each 66 feet long by 33 feet wide.

The reef modules were designed to allow sufficient depth for boats to pass over them, and the locations were approved by the U.S. Coast Guard, so that they would not be a navigational hazard. The modules provide 58,000 square feet of surface area as habitat for marine fauna. The cobble/boulder reefs provide another 30,000 square feet of surface area for marine habitat.

The mounds cover 13,000 square feet of harbor bottom. A total of 720 cubic yards of quarried stone were also used. Each cobble/boulder reef is comprised of 40 cubic yards of cobble and 80 cubic yards of boulder.

See the reef key map. For more environmental information, start from the top of our environmental section.