Animal/Bird/Marine Organism Impacts
Is Horseshoe Shoals an important area for birds? What kinds? How would they be affected by Cape Wind?
Many types of birds use Nantucket Sound, including waterbirds, shorebirds, and migrating landbirds. The Massachusetts Audubon Society (Mass Audubon) has provided extensive comments on Cape Wind and, partly with financial support from the Massachusetts Technology Collaborative, carried out several years of fieldwork to document what types of birds live on or fly through Horseshoe Shoal. For example, Mass Audubon surveys indicated that the proposed project site was not heavily used by terns, including federally endangered roseate terns. Horseshoe Shoal does appear to be an important area in winter for some species of sea ducks, which are abundant in Nantucket Sound. These birds use many other parts of the Sound as well. Click here1 to see results from Mass Audubon’s avian surveys in Nantucket Sound.
In 2006 Mass Audubon conditionally supported construction of Cape Wind, subject to additional surveys and measures to track and mitigate project impacts on birds and other living species. “Our preliminary conclusion is that the project would not pose a threat to avian species,” said Mass Audubon advocacy director Jack Clarke.2 The 2008 Minerals Management Service review of Cape Wind concluded that Cape Wind operations would have minor impacts on the various types of birds that use Nantucket Sound. When the study was released, Mass Audubon’s Clarke stated, “They [MMS] have done an adequate and thorough job of reviewing the potential environmental impacts with regard to avian life.”3 Click here to read the MMS assessment of how Cape Wind operations could affect bird life in Nantucket Sound (Section 5.3.2.4.2, pages 5-93 to 5-113).4
How would Cape Wind impact shellfish and other organisms that live on and beneath the seabed?
The Army Corps of Engineers concluded that installing, operating, and decommissioning the wind turbine towers and cables would have temporary, localized impacts on ocean-bottom fauna and shellfish in the project area. The main impacts are expected to be temporary, short-term increases in sediment deposition and suspended sediment levels associated with installing and removing the towers and buried cables. To minimize these impacts, Cape Wind plans to use monopole foundations for the turbine towers and state-of-the-art jet plows to install underwater cables. There are no data indicating a significant lobster population on Horseshoe Shoal. Click here5 to read the Corps assessment (Section 5.3, pages 5-31 to 5-47).
How would Cape Wind impact commercial and recreational fisheries in Nantucket Sound?
Nantucket Sound supports diverse commercial and recreational fisheries, and the Cape Wind project area contains habitat that has been designated Essential Fish Habitat for 17 federally managed fish and three federally managed invertebrates. The Army Corps of Engineers Draft Environmental Impact Statement (DEIS) found that fish could suffer habitat loss (from displacement of sediment on the sea floor) over small fractions of the total project area from building wind turbine towers and installing cables. However, the Corps observed that ocean-bottom habitat is similar throughout the Sound, so fish should be able to find suitable habitat nearby and are likely to return rapidly to the area after construction is completed and again after the project is decommissioned.
The Corps did not expect project construction and decommissioning to kill measurable numbers of finfish. It projected that underwater noise during construction could cause fish to move away temporarily, but would not cause permanent damage, and that underwater vibrations from the operating wind turbines generators would have “minimal or non-existent” impacts on finfish. Read Sections 5.4.5.1 and 5.4.5.2, pages 5-58 to 5-68 of the Corps DEIS for a discussion of impacts on fisheries.6
How would Cape Wind impact marine animals such as whales, seals, and turtles?
Marine species that are listed as endangered or threatened under federal or state law, and either occur or may occur in Nantucket Sound, include humpback, fin, and North Atlantic Right whales (federally endangered); loggerhead, Kemp’s ridley, and leatherback turtles (federally endangered or threatened); and gray seals (state species of concern). Other species of whales, dolphins, porpoises, and seals may also occur in the Sound and are federally protected under the Marine Mammal Protection Act, which establishes a general prohibition against “taking” marine mammals in U.S. waters. Gray and harbor seals maintain haul out and breeding grounds in Nantucket Sound year-round within 7 to 11 nautical miles (13 to 20.4 kilometers) of the project site.
Animals in the project area during construction can be expected to avoid noise sources temporarily in the same way that they would avoid a large ferry, passenger vessel, or fishing traffic. In its draft EIS the Army Corps of Engineers concluded that pile driving during construction of the wind farm would not generate underwater noise loud enough to harm marine mammals or sea turtles, and that noise from construction vessel traffic would not be loud enough to harm or harass marine mammals and sea turtles. Construction vessels would move slowly and would not be routed near areas where high concentrations of marine mammals or sea turtles have been reported. Click here7 to read the Corps assessment (Sections 5.5.6.1 and 5.5.6.2, pages 5-86 to 5-92).
Seven species of bats, none of which are listed on federal or state lists of rare, threatened, or endangered species, have been documented in surveys at the Massachusetts Military Reservation, which lies about 14.5 miles from the nearest offshore portion of the project at Horseshoe Shoal. Several species have been observed on Martha’s Vineyard. Most of these bat species are uncommon in the southeastern Massachusetts segment of their ranges. The Army Corps of Engineers concluded based on studies of these bat species’ behavior that the number of bats likely to be at risk of colliding with turbines in Nantucket Sound is extremely low because these species are not known to spend substantial periods of time flying over large bodies of open water, and their primary prey (insects) are typically found inland and along coastal areas. Click here8 for the Corps assessment (Section 5.6, pages 5-92 to 5-99).
Have impacts on birds and sea life been studied at other offshore wind farms?
Danish Offshore Wind: Key Environmental Issues, a 2006 book by Danish utilities and government agencies, describes impacts on birds, fish, and marine mammals based on observations from 2000 through 2006 at the Horns Rev and Nysted offshore wind farms. Very few negative impacts have been observed at either site.
At both sites the hard substrates around turbine bases were rapidly colonized by marine plants and animals such as mussels. Few effects on fish communities were documented: abundance and diversity were comparable within and outside of the wind farms. Seal populations near the Nysted farm decreased during pile-driving operations but rebounded shortly after construction. Porpoises behaved similarly at Horns Rev, while the porpoise population fell at Nysted during construction and is recovering slowly. Birds tend to avoid the area near the turbines and detour around the edges of the wind farms. Click here9 to read or download the book.
1http://www.massaudubon.org/news/index.php?id=114&type=news#download
2See “Audubon Review Supports Wind Farm,” Boston Globe, March 29, 2006
3See “Cape Wind Proposal Clears Big Obstacle,” Boston Globe, January 15, 2008
4http://www.masstech.org/offshore/docs/CapeWindDEIS.pdf, Section 5.3.2.4.2, pages 5-93 to 5-113
5http://www.nae.usace.army.mil/projects/ma/ccwf/section5.pdf, Section 5.3, pages 5-31 to 5-47
6http://www.nae.usace.army.mil/projects/ma/ccwf/section5.pdf, Sections 5.4.5.1 and 5.4.5.2, pages 5-58 to 5-68
7http://www.nae.usace.army.mil/projects/ma/ccwf/section5.pdf, Sections 5.5.6.1 and 5.5.6.2, pages 5-86 to 5-92
8http://www.nae.usace.army.mil/projects/ma/ccwf/section5.pdf, Section 5.6, pages 5-92 to 5-99
9http://www.ens.dk/graphics/Publikationer/Havvindmoeller/havvindmoellebog_nov_2006_skrm.pdf