Measurements of particle motion near the seafloor during construction and operation of the Block Island Wind Farm

Abstract

Noise radiation and particle motion from pile driving activities were monitored using multiple sensors during the construction of the first offshore wind farm off Block Island, RI, USA in 2016. The Block Island Wind Farm (BIWF) consists of five turbines in water depths of approximately 30 m. The substructure for these turbines consists of jacket type construction with piles driven to the bottom to pin the structure to the seabed. Pile driving operations generate intense sound, impulsive in nature, which radiates into the surrounding air, water and sediment producing particle motion that may affect marine animals. The particle velocity sensor package consists of a three-axis geophone on the seabed and a tetrahedral array of four low sensitivity hydrophones at 1 m from the bottom. The acoustic pressure acquired by the hydrophones will be processed to calculate particle motion. Data from the BIWF site will be compared with model predictions and published data from other locations. Recent measurements from the same wind farm location during the operational phase also will be presented. [Work supported by Bureau of Ocean Energy Management (BOEM).]