A six-month pilot project using dredged sediment to create 3D-printed artificial reefs in Mobile Bay has led to the deployment of six new reef structures that researchers hope will demonstrate how an abundant byproduct of channel maintenance can become a tool for coastal restoration.

The Mobile Bay National Estuary Program and partners recently sank the new reefs at a higher-energy site in the bay where they will be monitored to determine how well they withstand stronger wave conditions and how effectively they support marine life.

Half the reefs were constructed entirely from beneficially reused dredged sediment, while the other half were made from the same material blended with ground oyster shells. Researchers will compare the two materials to determine whether adding oyster shells improves habitat performance and encourages greater oyster recruitment.

The expansion comes after results from the first reef installation showed they remained intact through months of changing tides and weather while attracting a variety of marine life.

The monitoring will focus on how quickly marine organisms colonize the structures, including oysters, barnacles, algae and other species that depend on hard surfaces for attachment. Researchers will also evaluate how well the reefs hold up under more challenging environmental conditions than the sheltered pilot location.

Beyond testing reef performance, the project is intended to demonstrate a new use for one of the region's most abundant natural resources.

"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."

The reef structures are created by dewatering dredged sediment, shaping it with large-scale 3D printers and firing the material into durable ceramic-like forms designed to provide habitat for oysters, fish, crabs and other marine organisms.

If the larger field trial produces positive results, researchers hope the technology could become another option for converting dredged sediment into habitat restoration projects rather than treating it solely as a material requiring disposal. 

Gabriella Chavez is a Report for America corps member who writes about growth and development in Baldwin County and our natural spaces for Gulf Coast Media. Your donation to match our RFA grant helps keep her writing stories like this one; please consider making a tax-deductible gift of any amount today by visiting https://tinyurl.com/yaf8yf5n.