A preliminary numerical model of three-dimensional underwater sound propagation in the Block Island Wind Farm area

Abstract

The Block Island Wind Farm, consisting of five 6-MW turbines, is the first U.S. commercial offshore wind farm harvesting wind energy to generate electricity, located 3.8 miles southeast of Block Island, Rhode Island. In-situ underwater and airborne noise measurements were made during the construction and the first two months of the operational period for the purpose of environmental impact assessment. To better interpret the noise measurements and extend the noise propagation prediction beyond the coverage of listening stations, a three-dimensional underwater sound propagation model is created with a high resolution bathymetric map and a data-assimilated ocean dynamic model. The bathymetric map is made using the 3 arc-second U.S. Coastal Relief Model (CRM) with a 100-m horizontal resolution provided by the National Centers for Environmental Information (NCEI). The ocean model is extracted from the Regional Ocean Modeling System (ROMS) ESPreSSO (Experimental System for Predicting Shelf and Slope Optics) model covering the Mid-Atlantic Bight with a 5 km horizontal resolution and 36 terrain-following vertical levels. Temporal and spatial variability of noise propagation conditions is identified in the integrated acoustic and oceanographic model. Future model development incorporating surface wind waves and sub-bottom sediment layer structure will be discussed. [Work supported by BOEM.]The Block Island Wind Farm, consisting of five 6-MW turbines, is the first U.S. commercial offshore wind farm harvesting wind energy to generate electricity, located 3.8 miles southeast of Block Island, Rhode Island. In-situ underwater and airborne noise measurements were made during the construction and the first two months of the operational period for the purpose of environmental impact assessment. To better interpret the noise measurements and extend the noise propagation prediction beyond the coverage of listening stations, a three-dimensional underwater sound propagation model is created with a high resolution bathymetric map and a data-assimilated ocean dynamic model. The bathymetric map is made using the 3 arc-second U.S. Coastal Relief Model (CRM) with a 100-m horizontal resolution provided by the National Centers for Environmental Information (NCEI). The ocean model is extracted from the Regional Ocean Modeling System (ROMS) ESPreSSO (Experimental System for Predicting Shelf and Slope Optics) mo...