CSA Ocean Sciences (CSA), a company specializing in marine environmental consulting, announced the preliminary findings of a one-year study that evaluated the suitability of five nature-inclusive design (NID) materials to protect against erosion of offshore wind turbine and cable foundations at Tower Reef, an artificial reef managed by the Virginia Marine Resources Commission.

The study site, which was requested by the Bureau of Ocean Energy Management (BOEM), is located 0.6 nautical miles to the OSO of the Chesapeake Light Tower.

According CSA, the research determined that all five tested materials were suitable substrates for NID applications. Among them, the A-Cube demonstrated higher levels of roughness and a greater capacity to support healthy epibiotic colonization at the scale of this study.

Study development

In June 2023, following a desk study on NID materials and native and non-native species of the Mid-Atlantic region, the CSA Coastal and Ports Infrastructure team placed 15 artificial patch reefs (three of each design made with the five NID materials) within the sandy-bottom study site, located 12 nautical miles from Virginia Beach.

After 3 and 12 months, scientific divers from CSA and BOEM conducted monitoring studies to record the physical and ecological effectiveness of these erosion protection materials as healthy hard-bottom habitats for native reef communities (fish and invertebrates) and to assess the potential to attract invasive marine life.

Scientific divers were deployed to capture high-definition close-up photographs and perform a full visual assessment of each artificial reef during the 12-month project cycle. These images were also used to generate accurate 3D and 2D models, also known as photomosaics, to help calculate an accurate percentage of living epifaunal coverage on the reef units.

Additionally, CSA installed underwater cameras with time-lapse technology to document and monitor fish and invertebrate behavior around these artificial habitats.

The study utilized innovative underwater imaging techniques, including the use of orthophotography to monitor the physical and biological conditions of the study materials, addressing key issues regarding invertebrate species colonization and the use of demersal fish.

BOEM Contracting Officer Representative Brandon Jensen noted that "the successful collaboration between BOEM and CSA to evaluate the suitability of these NID materials comes at an important time to understand the impacts of different materials that could be used in offshore wind energy projects in the United States."