Passive acoustic monitoring during the construction of the Coastal Virginia Offshore Wind project

A suite of hydrophone arrays was deployed to monitor pile driving sound and seafloor particle motion during construction of two wind turbine towers in the Coastal Virginia Offshore Wind (CVOW) project in May 2020. The primary objective of this passive acoustic monitoring (PAM) work was to assess the effectiveness of bubble curtains for underwater noise mitigation. The arrangement of the PAM tracks also enabled studies of azimuthal and range dependencies of pile driving sound propagation. Measurements of water temperature, salinity and surface heights were made during the monitoring period to assess underwater sound propagation conditions. PAM data showed that the bubble curtain effectively reduced the pile driving noise above 200 Hz, and a significant azimuthal dependency was observed. Statistical analyses of pile driving noise will be presented, along with recommendations for future wind farm construction monitoring, especially on marine mammal acoustic monitoring during construction. [Work supported by the Bureau of Ocean Energy Management]