A pilot project that turns dredged sediment into 3D-printed artificial reefs is expanding in Mobile Bay, with researchers hoping the approach can turn a routine waste byproduct into a tool for coastal restoration.
The Mobile Bay National Estuary Program, working with the U.S. Army Corps of Engineers, recently deployed six new reef structures at a higher-energy site in the bay following a successful six-month pilot. The new reefs will be monitored to see how well they hold up under stronger wave conditions than the sheltered pilot location and how effectively they support marine life.
Two Materials, One Comparison
Half of the newly deployed reefs were built entirely from beneficially reused dredged sediment, while the other half combine that same sediment with ground oyster shells. Researchers plan to compare the two materials to determine whether adding oyster shells improves habitat performance and encourages more oysters to settle on the structures.
The reefs themselves are created by dewatering dredged sediment, shaping it using large-scale 3D printers, and firing the material into durable, ceramic-like forms designed to give oysters, fish, crabs and other marine life a place to attach and grow.
Building on Early Success
The expansion follows encouraging results from the original pilot reef, which stayed intact through months of shifting tides and weather while drawing a variety of marine life. Researchers will now track how quickly organisms such as oysters, barnacles and algae colonize the new structures at the more exposed site.
“This is a U.S. Army Corps-led project and shows the value in collaboration when it comes to resource management,” said Henry Perkins, private sector program lead for the Mobile Bay National Estuary Program. “There’s 4 million tons of sediment dredged from the shipping channel each year, which gives the management community lots of opportunities to discover new and useful ways to reuse this recurring natural resource.”
If the expanded field trial continues to produce positive results, researchers say the technology could become a standard option for turning dredged sediment into habitat restoration projects instead of treating it purely as waste requiring disposal.