Posted on July 20, 2026
The U.S. Army Corps of Engineers (USACE) is converting sediment dredged from Mobile Bay’s navigation channels into 3D printed reef structures aimed at restoring oyster habitat and strengthening coastal resilience in Alabama.
The project, led by USACE’s Engineer Research and Development Center (ERDC) alongside the Mobile District and regional partners, treats a byproduct of channel maintenance — sediment that must be removed annually to keep waterways navigable — as a raw material for environmental restoration rather than waste to be disposed of.
“The real opportunity is to keep sediment working within the coastal system and use it as a resource,” said Elizabeth Godsey, Regional Sediment Management and Engineering With Nature Practice Lead at USACE. “By combining dredged material with innovative design and printing methods, we can develop solutions that support navigation, restore habitat, and increase coastal resilience.”
Storms, shoreline change and other environmental stressors have driven habitat loss and a decline in oyster populations in Mobile Bay. Oysters function as a keystone species in Alabama’s estuaries, filtering water, supporting other marine species and helping reduce coastal erosion by influencing nearshore waves and sediment movement.
Printing habitat from harbor sediment
Researchers in ERDC’s Environmental Laboratory collected fine-grained sediment from the Blakeley Island Confined Disposal Facility and developed a printable sediment-based mixture to fabricate dome-shaped reef structures. The domes feature varied surfaces, openings and internal geometries intended to mimic the habitat complexity of naturally forming oyster reefs and provide a stable substrate for larval colonization.
“We are using fine-grained dredged sediment from Mobile Harbor as building material,” said Dr. Al Kennedy, a research biologist at ERDC-EL. “The layers and complex geometry of the printed domes provide microhabitats and surface structures that are ideal for larval colonization.”
Early results and next steps
Early installations in Mobile Bay showed that the printed domes attracted barnacles and oysters at rates comparable to those of terracotta, the material USACE considers an ideal reference substrate, according to Kennedy. USACE reported that the structures are also helping reduce wave energy and retain coastal sediment.
Future phases of the project will compare durability and colonization rates between domes made entirely of dredged sediment and domes blended with 10 percent oyster shell and will explore on-site, on-demand printing using a hopper system to reduce transportation costs.
USACE is also finalizing a national Engineering Practice Guide for Oyster Reefs.
