Seafloor disturbance monitored

At wind farm site
Sun, 04/02/2017 - 6:45am

The condition of the seafloor appears to be a component of the Block Island Wind Farm project that is requiring close attention of late. While the shallow burial depth of a portion of National Grid’s undersea cable off the Town Beach is being addressed, the Bureau of Ocean Energy Management, and Deepwater Wind, the project’s developer, are using new technology to monitor “seafloor disturbance” at the base of the wind farm’s turbines.

BOEM is an agency within the United States Department of the Interior that was integral in siting the wind farm via what is called the Ocean Special Area Management Plan. The OceanSAMP contains comprehensive regulations that outline Rhode Island's process for ensuring management and protection of its ocean resources and activities.

Stephen Boutwell, a spokesman for BOEM, told The Block Island Times that “The Bureau of Ocean Energy Management, along with Deepwater Wind, is testing a new scour sensor to evaluate the effectiveness of scour protection that is already in use at the (wind farm site).” Scour protection is employed to monitor changes in the seafloor around the wind farm’s steel foundations. Boutwell said that BOEM deployed a 100-foot vessel, the Megan Miller, to conduct monitoring at the site in early March.   

Boutwell said the research will be used to address “seafloor disturbance due to the presence of the turbines. The OceanSAMP provided baseline or background data about the seafloor sediment type and distribution that can be used to determine if there are changes in sediment distribution as a result of the presence of turbines. While not generally thought to be a significant effect, BOEM wanted to take advantage of this opportunity to acquire more quantitative observations to address the effects for future development.”

The monitoring is part of “the Real-time Opportunity for Development Environmental Observations project,” said Boutwell. “RODEO collects real-time measurements of the construction and operation activities from the first offshore wind facility built in the United States.”

In order to collect information, Boutwell said, “The researchers were downloading data from an instrument called an Acoustic Waves and Currents sensor that measures both the local currents and wave height. This information is being collected simultaneously with monitoring scour, or the potential loss of sediment, around the base of turbine three.”

“The monitoring is scheduled for one full year with quarterly retrieval of the data,” said Boutwell, who noted that monitoring is scheduled to end in July. “With this research, BOEM hopes to have a more definitive answer regarding seafloor scour that relies on real-time observations. Real-time measurements of the construction and operation of (wind farm) facilities will allow for more accurate assessments of the actual environmental effects.”