EPA DETAILED COMMENTS ON THE DRAFT ENVIRONMENTAL IMPACT STATEMENT, CAMPO SHU'LUUK WIND PROJECT, SAN DIEGO COUNTY, CALIFORNIA
The alternatives analysis is the heart of the Environmental Impact Statement (40 CFR 1502.14). The alternatives analysis should present the environmental impacts of the alternatives in comparative form, thus sharply defining the issues and providing a clear basis for choice among options by the decision-maker and the public. This is especially important for this DEIS because no preferred alternative has been identified.
The analyses in the DEIS do not clearly distinguish impacts among alternatives. For those impacts that the DEIS concludes are significant (biological, noise and visual resources), the DEIS simply states that they are significant but does not distinguish their nature or intensity between alternatives. As an example, to better convey impacts, the alternatives analysis could quantify the number of individuals that could be impacted for each alternative (birds, bats, people) and/or better characterize the intensity of the impact for each alternative. Since there is a difference in the number of turbines among the alternatives, a clear depiction of impacts is valuable information for the decision-maker and the public.
Recommendation: We recommend attempting to quantify or otherwise more specifically characterizing the differences in impacts among the alternatives in the FEIS. Update Table 2.6-1 to reflect these changes.
The noise impact assessment utilized the Federal Energy Regulatory Commissions’ noise standard of 55 dBA Ldn (A-weighted decibels day-night average level) as a significance threshold for noise impacts. The DEIS concludes that operation of turbines under Alternative 1 could expose on-Reservation residences to significant noise levels but that no off-Reservation properties would receive significant noise levels exceeding the FERC standard. However, Appendix E states that “Under Alternatives 1, 2, and 3, operation of the turbines would expose off-Reservation residences to noise levels that exceed the FERC guideline of 55 dBA Ldn.” (p. 71). The DEIS also states that wind turbines cannot be relocated, therefore no feasible mitigation measures are available to reduce noise levels (p. 4.10-8).
In previous comments, we recommended using C-weighted noise metrics as well as the usual A-weighted analysis to cover the low-frequency sounds often associated with wind turbines. The noise analysis in the DEIS proper does not discuss low-frequency noise, but Appendix E states that low-frequency noise would not result in adverse noise impacts because all residences and sensitive receptors would be located a quarter-mile (1,320 feet) from turbines. It cites a 2009 study that concluded that measured noise levels beyond 1,000 ft were below interior low-frequency noise criteria for bedrooms, classrooms and hospitals and, therefore, would not cause more than minimal annoyance, if any (App E, p. 69). No additional information is provided regarding the low-frequency criteria that were used. The National Academy of Sciences1 has stated that noise produced by wind turbines generally is not a major concern for humans beyond a half-mile or so because various measures to reduce noise have been implemented in the design of modern turbines.
Potential health impacts from noise were not discussed. The World Health Organization recommends that, where noise is continuous, the equivalent sound pressure level should not exceed 30 dBA indoors if negative effects on sleep are to be avoided. When the noise is composed of a large proportion of low-frequency sounds, a still lower guideline value is recommended, because low frequency noise can disturb rest and sleep even at low sound pressure levels1. Additionally, for the construction phase, the DEIS states that there would likely be some construction activity at nighttime (p. 2-18); this should be discussed in relation to potential health impacts. Because of the proximity of proposed turbines to both on and off-Reservation populations, some of which are characterized as environmental justice populations, additional discussion of noise impacts is recommended.
Recommendation: Clarify the inconsistencies between the DEIS and Appendix E regarding the significance of noise impacts for on and off-Reservation populations. Discuss low-frequency noise impacts in the Final EIS, including potential impacts to children’s health pursuant to Executive Order 13045 - Protection of Children from Environmental Health Risks and Safety Risks. Discuss potential health impacts of construction noise occurring at night and whether this is necessary for the project. We recommend distinguishing noise impacts among alternatives, including quantifying the number of sensitive receptors that would be exposed for each alternative. This information may be useful to decision-makers and reveal opportunities to minimize impacts to the most affected receptors during micro-siting of turbines.
Impacts to Raptors
We are concerned with the significant impacts to migratory birds, especially red-tailed hawks. The DEIS predicts high mortality rates to individuals and significant adverse effects to the population on the Reservation. The DEIS does not specify the expected raptor mortality rates, but states that mortality would be expected to occur at a level similar to the average calculated for other projects in the western portion of the Pacific Flyway. In addition, there is potential for golden eagle mortality; however, we note that Alternative 3 is predicted to result in lower golden eagle collision risk (p. 4.4-53).
Recommendation: Specify the expected raptor mortality rates for each alternative in the body of the Final EIS. We strongly recommend that an Eagle Conservation Plan be prepared for the project and that the proponents pursue a golden eagle programmatic take permit with the U.S. Fish and Wildlife Service. We recommend that BIA include this as a mitigation measure in the ROD and as a condition of approval. The DEIS should clarify whether Alternative 3 would be expected to have a lower risk of raptor collisions, in general, in addition to its lower golden eagle collision risk.
Impacts to Bats
We are concerned with the significant impacts to bats identified in the DEIS (p. 4.4-38). The DEIS does not specify the expected bat mortality rates, but states that bat mortality rates under Alternative 1 are expected to be similar to the average calculated for projects in the western portion of the Pacific Flyway (p. 4.4-38). The DEIS states that the effect of this mortality on the local bat species populations would likely be minimal (p. 4.4-39), but does not provide the basis for this conclusion. It also states that mitigation measures MM BIO-2(a) through (c) are provided to avoid, minimize, and mitigate adverse impacts to bats, but it is not clear how these measures would reduce impacts. BIO-2(a) assigns a project biologist to address permit requirements, none of which are applicable to bats; BIO-2(b) involves environmental training; and BIO-2(c) addresses weed management. The DEIS does include a recommendation for a Bird and Bat Conservation Strategy in MM BIO-3(d) to include minimization and compensation for adverse impacts, but no further information is provided on whether or how this could be accomplished for bats.
Recommendation: Specify the expected bat mortality rates for each alternative in the body of the Final EIS. Clarify how the mitigation measures identified would mitigate impacts to bats.
We recommend further discussion of potential mitigation for bats. The DEIS indicates that most bat fatalities have been recorded in the Fall, coinciding with peaks in echolocation activity, and that bat species are at most risk during August and September because juveniles are flying and fall migration is occurring. It also states that low wind speeds have been correlated with increased bat fatalities. The DEIS should discuss bat monitoring and whether it’s possible to turn off turbines during some of these conditions to minimize bat mortality. Additionally, because the alternatives vary in terms of the size of the turbines, the FEIS should discuss any information available regarding differences in pressure change for various turbine sizes that could affect barotrauma and other impacts on bats.
The DEIS states that coordination with the Campo Environmental Protection Agency was conducted during the cultural resource surveys for the project and that the Tribe coordinated Native American participation for the pedestrian survey (p. 3.6-10). It is not clear if tribes other than Campo were consulted for the project. Additionally, the DEIS states that, if human remains are discovered, excavation may take place only with the consent of the Tribe and the BIA, and must follow the requirements of the Archeological Resource Protection Act (ARPA) (p. 4.6-9).
Recommendation: In the FEIS, clarify the extent of tribal coordination that occurred for the project and that would occur if human remains or other artifacts were discovered during project construction. The DEIS states that the eastern staging area for the Operations and Maintenance facility would not impact a known cultural resource. Since this eastern option also appears to avoid riparian habitat, we recommend selecting the eastern location (O&M Option 2).