Key Researchers: Kim Olsen, Robert Erickson, Edmund Hughes, Brian Diunizio, and Scott Sharpe
Multi-beam surveys were conducted in 2021 at the Block Island Wind Farm to assess the recovery of the seafloor after completion of the construction of the wind farm in 2016. Some of the depressions from the liftboat legs used during the installation of the turbines could still be observed on the seafloor. These depressions were not as large as in previous observations indicating that sediment is slowly filling them in. The depressions range from 10 to 50 centimeters deep. Scour, where sediment is removed by currents around the base of the turbine foundation, was also observed with depths of 5 to 20 centimeters.
Findings
- Depressions from the lift boat legs continue to recover with some no longer discernable
- Scour around the base was observed and appears to be dynamic, previously observed scour is gone and new scour locations are observed
- The recovery rates may be a function of the sediment type present around the WTGs
How BOEM will use this information
- Provide additional information necessary for BOEM’s evaluation of environmental effects of future facilities
- Provide data to improve the accuracy of models and analysis criteria to establish mitigation and monitoring requirements