Marine environmental consultancy CSA Ocean Sciences has concluded a year-long study on artificial reefs in offshore wind farms for the U.S. government. The study, commissioned by the Bureau of Ocean Energy Management (BOEM), evaluated the suitability of five Nature Inclusive Design (NID) materials for use in offshore wind turbine and cable foundation scour protection at the Tower Reef artificial reef site, managed by the Virginia Marine Resource Commission.
In June 2023, CSA's Ports & Coastal Infrastructure team deployed 15 artificial patch reefs made from five different NID materials, each material tested in triplicate. These reefs were placed in a sandy bottom survey area 12 nautical miles off the coast of Virginia Beach. Over the following year, CSA and BOEM divers conducted monitoring surveys at three- and twelve-month intervals to assess both the physical and ecological effectiveness of the reefs as habitats for native reef species and to monitor the risk of attracting invasive sea life.
The study involved high-definition photographic imaging, visual assessments, and the creation of 3D and 2D models to calculate the living coverage on the reefs. Underwater time-lapse cameras were also installed to document the behavior of fish and invertebrates around the artificial reefs.
The results indicated that all five tested NID materials were suitable as substrates for scour protection. The A-Cube material, in particular, was found to have higher levels of rugosity and demonstrated a greater ability to support healthy epibiotic colonization compared to the other materials tested.
Brandon Jensen, BOEM's Contracting Officer Representative, commented on the importance of the study: “BOEM's successful collaboration with CSA to assess the suitability of these NID materials comes at an important time for understanding the impacts of different materials that may be used in offshore wind energy projects in the United States.”
Jensen added that while the study supported the applicability of the NID materials, further research would be needed to understand how different scour materials affect marine life, particularly seabed species. This would help determine whether the species attracted by the materials have a positive or negative impact on the surrounding marine environment.
