While much of the dispute about the 130 wind turbines proposed by Cape Wind has been concerning what’s above the water, the company now is turning its attention to what lies below.
Starting today, Cape Wind will begin a four-part geological survey of the 25 square miles of Horseshoe Shoal on Nantucket Sound, where it proposes to build the 440-foot turbines.
“The work starting is really the beginning of what will be a continuous presence of Cape Wind on the shoal, up to construction,” Cape Wind spokesman Mark Rodgers said. “The fact is, in construction projects, these types of activities are considered the official beginning of construction.”
The four-step geological survey will give Cape Wind more information about the seafloor and subsurface, including topographical changes, the layers of materials in the ocean floor and whether foreign objects – including cultural artifacts – are present.
It’s a precursor to the construction of foundations for the proposed turbines, Rodgers said. The turbines’ steel monopole foundations – pipelike structures about 15 feet in diameter – will be driven into the seabed to a depth of 80 feet and filled with sediment.
The survey is important for the engineering and design of the foundations and supports, as well as the cables running through the area, said Tom McNeilan, vice president of Fugro, the company performing the survey. About 50 scientists and engineers from Fugro, a Dutch company with a base in Norfolk, Va., and other companies will conduct the survey.
Geological surveying was done during Cape Wind’s federal permitting process but was a less-specific regional look at the area’s underwater geography, he said.
Researchers will begin by acoustically imaging the area via a 34-foot catamaran equipped with several types of equipment. They will get an image of the seafloor akin to a topographical map, information on geologic structures and a “pseudo-photograph” of the area, McNeilan said.
Next, “vibracore” samples of the seafloor will be taken at each of the proposed 130 turbines by scientists on a 100-foot vessel. Those will provide a picture of the archeological properties of the areas.
A third stage of surveying uses a barge to take “seafloor cone penetration tests,” which use a rod pushed into the subsurface of the shoal to determine the physical properties of the sand where the monopole foundations will be sunk.
Finally, McNeilan said, scientists will bore deeper into the ground at some of the proposed turbine locations using another barge.
Along with finding the specific geographical properties of Horseshoe Shoal, the survey will also determine if any metallic objects or those of cultural interest are in the area, he said.
Members of the Wampanoag Tribe of Gay Head (Aquinnah) have in the past expressed concern the area was home to some of the tribe’s ancestors before being submerged because of sea-level rise.
Work will be done seven days a week through September or October, McNeilan said. Three to six researchers, a crew and a marine mammal observer will be on each trip, McNeilan said.
Cape Wind notified the United States Coast Guard and boaters of the activity but doesn’t anticipate any interference with boating, fishing or ferries during the survey, Rodgers said.
He would not elaborate on the “multimillion dollar” cost estimate of the survey included in a press release, he said. Cape Wind has spent about $50 million so far on its project.
Though the United States Geological Survey has extensively studied more than 50 percent of Massachusetts’ waters of about 33 feet and deeper, “that area right there has really not been systematically and fully investigated,” Walter Barnhardt, a marine geologist and director of the USGS Woods Hole Coastal and Marine Science Center, said.
Opponents do not agree the survey is a precursor to construction.
“Survey work is standard and doesn’t change the fact that Cape Wind doesn’t have the authority to begin construction,” Alliance to Protect Nantucket president and chief executive officer Audra Parker said.
Cape Wind still needs final approval from the Federal Aviation Administration. The administration initially approved the project, but in October a federal judge sent the decision back to the FAA for further review.
The company also faces lawsuits from the Aquinnah tribe, the town of Barnstable and the Alliance, though more than a dozen legal challenges have been dismissed in the past nine years.
Cape Wind has sold more than 75 percent of the power from the wind farm but hasn’t announced its financial backers. The project is expected to cost more than $2.5 billion.
|Wind Watch relies entirely
on User Funding