Old bridge gets new life as reef
The debris from the old Jamestown Bridge has found a new career as two artificial reefs in Rhode Island Sound.
Half of the 24,000 cubic yards of concrete and rebar from the bridge demolition now lies in 60- to 65-feet of water south of Newport's Sheep's Point. The other half is in 80-to 90-feet of water just west of Gooseberry Island off Gooseberry Beach. The steel from the bridge superstructure was recycled.
The artificial reefs are being studied in the "Jamestown Bridge Reef Assessment," a five-year project contracted to the Department of Environmental Management (DEM) Fish and Wildlife Division from the Department of Transportation (DOT). Richard Satchwill, a DEM Fish and Wildlife biologist is the principal investigator on the project.
The project is a requirement of the Army Corps of Engineers, Satchwill said. "They have jurisdiction over every government agency, even Coastal Resources Management Council. They require DOT, the agency holding the permit to dispose of the debris for the artificial reef, to provide the data gleaned from the project."
"We started writing plans for the study as the bridge was being demolished," Satchwill said. "The purpose of the project is to determine if the reefs meet specific goals. We are looking for evidence that they are providing habitat for juvenile fish and other marine life."
He explained that cold water at depths with little light is not conducive to floral marine growth. "However, even though we just started depositing the debris in 2006, it is already showing results with mollusks, fish and other forms of marine life establishing residence," Satchwill said.
"This month we created cryptic habitats using 20 wire baskets containing 250 surf clam shells each. The units are constructed with PVC piping that gives access to the center of the baskets for mollusks, fish, crabs and other sea creatures.
"We contracted the workboat "Beavertail" to transport the units and lower them to the bottom around the artificial reefs," Satchwill said. "We also engaged divers from Ocean Opportunity and Conusub to help us put everything in place and record data."
He explained how the concrete from the bridge provides hard surfaces needed to attract clams, shellfish and sessile animals and mussels so they have something hard to grab. "The baskets of shells are there for the same purpose, but we can bring them to the surface and study the progress," he said.
"Every year we will bring up two of the 20 baskets. That way we can record yearly progress of growth, mortality in some cases, and density of different species over a five year period," Satchwill said.
"DEM Fish and Wildlife Division is the only government agency involved in the actual work on the project," Satchwill said. However, a University of Rhode Island graduate student is working with the team, but URI is not involved as an instritution. She is writing a thesis on early colonization of artificial reefs, and is sharing her data. "Her objectives are different from ours, but certainly of interest," he added.
"Everyone from scientists to fishermen will benefit from the data and the reefs themselves," Satchwill said. "They provide habitat for lobsters, shellfish, a variety of fin fish, and mollusks. An array of marine life will establish residence and proliferate, if all goes well," Satchwill said.