Alternative Energy Draft EA - NASA Visitor Center at Wallops Flight ...

Environmental Consequences
is the approved harvest of large numbers of waterfowl each year. The Commonwealth of
Virginia allows harvest of waterfowl in numbers that would not be matched by the fatality from
the proposed wind turbines at WFF. According to the USFWS (Richkus et al., 2008), Virginia
harvested more than 131,000 ducks in 2006 and 2007, a small proportion (approximately 8
percent) of the total number of ducks harvested along the Atlantic Flyway in those same years.
The USFWS also allows for localized management of Double-crested Cormorant, one of the
identified carcasses at WFF, because it can be a nuisance species in certain areas. These
examples demonstrate that there are greater threats to avifauna at the individual and population
level than the two proposed wind turbines at WFF.
A post-construction monitoring study has been proposed (NASA, 2009d) as a means of ground
truthing the wind turbine’s risk profile and to provide data for comparison of actual avian and bat
mortality at the wind turbines with mortality estimated for the existing tower structures. The
need for BMPs would be determined once the post-construction study is implemented. If it is
determined that there is a need to mitigate for any potential impacts on avifauna at the proposed
WFF wind turbines, potential avoidance and/or minimization BMPs could be implemented to
reduce the potential long-term (direct and indirect) impacts. Since research is on-going regarding
wind energy projects and how to avoid and minimize potential impacts, many BMPs have yet to
be developed and/or proven. Details of the mitigation measures and proposed post-construction
study can be found in Chapter 5 of this EA.
Residential-Scale (2.4 kW) Wind Turbines
A qualitative evaluation of the potential for risk to birds from residential-scale turbines is
provided in the absence of site-specific information. The general assumption is that small,
residential-scale wind projects have minimal impacts on birds and less impact than the larger
utility-scale turbines. For example, the American Wind Energy Association (AWEA) says that
“anecdotal evidence indicates that birds occasionally collide with small wind turbines as they do
with any other type of structure. However, such events are rare and very unlikely to have any
impact on bird populations. Large, utility-scale wind turbines account for less than 0.003% of all
human-caused bird deaths, and small wind turbines have even less of an impact.”
Further, Southwest Windpower, Inc., the manufacturer of 2.4 kW turbines, states in their
Residential Wind and Birds fact sheet that “although no formal studies have been conducted with
residential wind generators like those produced by Southwest Windpower, Inc., bird strikes are
even rarer. This is due in part to their shorter towers [9-30 meters (30-110 feet)], and relatively
small blades [1-3 meters (3-12 feet)] in diameter. Also, residential wind generators are typically
installed over a more dispersed area, further reducing the chance of bird collision.” Neither
AWEA nor Southwest Windpower, Inc. track avian mortality at residential-scale windfarms and,
therefore, project-specific information was sought during a literature review.
A review of relevant literature and discussions with industry experts were conducted to
determine if there were post-construction monitoring results for projects similar to WFF that
would be instructive in assessing the potential for avian risk from the 2.4 kW turbines. Postconstruction
monitoring to assess avian mortality rates generally has been conducted at the larger
utility-scale projects and not on the smaller turbines projects like the 2.4 kW turbines proposed at
WFF. In a review of avian mortality data for 33 wind turbine sites in the United States and
Canada, Barclay, et al. (2007) determined that that the height of turbines had no effect on bird
mortality rate (corrected mortality rates ranged between zero and nine per turbine per year). With
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