Underwater noise associated with the life cycle of an offshore wind farm area, including during site surveys, construction, operations and maintenance, and decommissioning. Illustration from Mooney et al. 2020.

Phase 1 of 4: Survey, 10 years. Noise Sources: Multi-beam/sidescan sonar, and sediment coring. This phase has the second highest acoustic impacts.

Phase 2: Construction. 3 to 5 years. Noise sources: Vessels, Dredging, and pile-driving. Image indicates that the construction phase has the highest acoustic impacts, generating noise from the ocean surface and the ocean floor. 

Phase 3: Operation. 20 to 30 years. Noise sources: Broadband and tonal turbine noise. This stage has the lowest acoustic impacts.

Phase 4: Decommissioning. 2 years. This stage has the second lowest acoustic impacts.