Key results and recommendations from a three-year benthic habitat and turbine structure epifauna monitoring study that was conducted at the Block Island Wind Farm (BIWF) Project Area are presented in this report. The overarching goals of the multi-year monitoring study were to gather and analyze data to improve understanding of the following:
- The nature, as well as potential spatial and temporal scales, of anticipated alterations in benthic habitats, including macrofaunal community characteristics (e.g., species abundance, richness, diversity, assemblage structure, and biomass), surficial sediment characteristics (e.g., particle size distribution, organic content), and relationship dynamics between macrofaunal communities and their associated environments at the BIWF facility.
- Characteristics of the epifaunal communities colonizing the turbine foundations (e.g., species assemblages, percent cover, biomass, growth thickness).
- Potential physical effects of the epifaunal growth (e.g., total added weight, change in surface area and drag forces) on turbine structures.
The following types of data were collected and analyzed:
- Benthic grab samples collected at randomly selected locations within three distance bands around three of the five BIWF turbines (30 to 90 meters [m] from the turbine center point) and three control areas (three years). These samples were collected using a Smith McIntyre grab sampler that was deployed from a vessel.
- Manual benthic grab samples collected at three of the five BIWF turbines at randomly selected locations (15 to 30 m from turbine center point; very near-field area [one year], and at defined locations along a transect underneath the turbine structures [i.e., within the footprint, two years]). These samples were collected by divers using SCUBA by manually excavating sediment into fine mesh bags.
- All benthic grab samples were analyzed in the laboratory for macrofaunal community characteristics, sediment grain size distribution, total organic matter, and total organic content.
- Seabed video accompanying each round of vessel-based grab sampling (three years).
- Visual observations from seabed photography transects around three of the five turbines and three control areas obtained by camera float missions (three years) and diver-towed missions from under the turbines (two years).
- Visual observations from video data of epifauna on turbine foundation structures (two years).
- Epifauna biota scrape samples collected from selected locations on one turbine (two years).