In 2011, the Department of the Interior (DOI) commissioned an independent peer review of the Draft Environmental Impact Statement (DEIS) to determine if (1) appropriate scientific information was used, (2) conclusions drawn from the information are reasonable, (3) significant information was omitted from consideration, and (4) interpretations of the information by the NPS are reasonable. The peer review focused on the scientific underpinning of the DEIS. The Final Report on Peer Review of the Science Used in the National Park Service’s Draft Environmental Impact Statement Drakes Bay Oyster Company Special Use Permit (Atkins Project No. 100025958; referred to here as the “Atkins report”) was released in March 2012. The committee was asked to evaluate whether the Atkins report is “fundamentally sound and materially sufficient.”
The Atkins report peer review was limited to scientific information contained in Chapters 3 and 4 of the DEIS. The review did not include “the intensity definitions or their conclusions” nor did they “make recommendations on whether a particular alternative should be implemented or whether they would have conducted the impact analysis in a similar manner,” (Atkins, p. 1). Atkins selected 5 external reviewers based on their qualifications and expertise in the 4 topics identified by DOI: (1) Marine Estuarine Ecology and Coastal Zone Management; (2) Water Quality; (3) Soundscapes; and (4) Socioeconomics. Each reviewer conducted their assessment independently. The Atkins report includes a summary prepared by their staff in addition to the individual reviews from the selected experts.
Although the reviewers selected by Atkins are well-qualified, the committee found that the range of expertise covered by these experts was insufficient to address all of the scientific topics covered in Chapters 3 and 4 of the DEIS. In particular, the committee felt that additional expertise in water quality, wildlife (e.g., harbor seals, fish), and terrestrial soundscapes would be needed to provide a thorough peer review. The Atkins report identified several instances where scientific evidence, interpretations or citations were insufficient or where alternate conclusions could have been reached, particularly in the discussion of marine estuarine ecology. The exception was the DEIS treatment of socioeconomics which the Atkins reviewer judged to be “vague at best, and misleading at worst” (Atkins, p. 5, 88). Apart from the critique of the DEIS socioeconomic section, the Atkins report concludes: “In general, the reviewers found the DEIS to be well-written with adequate analysis and use of available scientific information.” The committee reviewed the Atkins report and identifies issues that were not covered or where there was some disagreement with the Atkins report. As a consequence of the limited range of expertise of the reviewers and the constraints placed on the review (limited to DEIS Chapters 3 and 4, did not include the intensity definitions or conclusions), the committee does not consider the Atkins report to be “fundamentally sound and materially sufficient.”
Specific comments on the individual reviews in the Atkins report are provided below. The committee notes that not all of the resource categories in the DEIS were reviewed in the Atkins report. The Atkins report covered wetlands, birds, bivalve aquaculture, eelgrass, and benthos under the topic “Marine Estuarine Ecology and Coastal Zone Management” and included the following DEIS categories: water quality, soundscapes, and socioeconomics. Impacts on harbor seals, special status species, and the coastal flood zone were not addressed.
Resource Categories Addressed in the Atkins Report
Marine Estuarine Ecology and Coastal Zone Management
Wetlands and Birds (p. 57-66)
This review focused on wetlands and birds, but also incorporated comments on other sections. The committee agrees with the comments of this review related to wetlands, birds, and eelgrass overall. The review stated that given the limited available data for many of these topics, the conclusions are reasonable and generally well supported. The review found that the DEIS also does an acceptable job of presenting the limitations posed by the data, although some topics and interpretations were “either lacking support or fundamentally incorrect" (Atkins, p. 57).
With regard to birds, the review found that the DEIS reasonably describes the ecological importance of Drakes Estero and the potential disturbances due to noise and presence of small boats under alternatives B, C, and D. The review did not agree with the argument that potential invasive invertebrate fouling of eelgrass blades would reduce consumption by migratory Brant (Atkins, p. 58). It also disagreed with the DEIS on recreational clamming; while the DEIS dismissed these effects, the review found that these activities could result in extensive and long-term disturbances to the benthos.
In general, the review emphasized that the DEIS should recognize the substantial uncertainty associated with many of the conclusions, such as those regarding the impacts of mariculture on shorebird behavior, estimates of eelgrass cover, and the contribution of mariculture to the spread of non-indigenous species in the Drakes Estero ecosystem. It critiques the use of data from San Francisco Bay to address issues of eelgrass and water quality impacts because it is not a comparable embayment and provides little insight into the dynamics of Drakes Estero. The review finds that it “remains an open question entirely whether oyster filter feeding has any effect positive or negative on eelgrass” (Atkins, p. 61), The committee concurs with this review’s appraisal of these issues in the DEIS.
Bivalve Mariculture (p. 67-75)
The committee found this review overall scientifically sound and balanced with a few exceptions. The review brought up many relevant points and provided an extensive list of additional references.
The committee did not agree with the suggestion that “… there are no data to support a notion that in this system aquaculture improves water quality or habitat quality for eelgrass,” (p. 68-69) The committee agrees with the review that there is no direct evidence that oyster culture benefits eelgrass in Drakes Estero. However, as discussed in Chapter 3 under water quality, sufficient data exists on oysters, including the Pacific oyster, to suggest that oyster mariculture in Drakes Estero could increase water clarity. At the same time, there is evidence from other ecosystems for causal relationships between bivalve growth and seagrass productivity that show both positive (Peterson and Heck, 1999; Peterson and Heck, 2001a; 2001b; Carroll et al., 2008) and negative (Vinther et al., 2008) relationships. The committee concluded that the DEIS would be unbalanced if it only discussed the adverse impacts of oyster mariculture in Drakes Estero.
This review in the Atkins report is consistent with the committee’s conclusions in highlighting the risk of spreading nonindigeneous species through mariculture operations. The review of benthic fauna is consistent with the committee’s assessment of these issues.
Water Quality (p. 77-79)
This review covered the topic of chemical toxicology thoroughly, but did not include other aspects of the effects of DBOC operations on water quality that the committee regarded as important for a thorough review of the DEIS.
The review focused on the potential effects of chromated copper arsenate (CCA) leached from pressure-treated wood used by DBOC for docks and oyster cultivation racks, and presented this as the primary source of uncertainty concerning impacts of DBOC operations on water quality. The review concluded that (1) the analyses and interpretations of environmental impacts of oyster mariculture on marine water quality are reasonable and appropriate, and (2) the DEIS includes and applies the best available science on the impacts of shellfish mariculture. Water quality parameters that could be affected by DBOC operations were not discussed in the DEIS, in part because such data do not exist or are
limited in scope (e.g., turbidity, suspended organic matter, nutrient concentrations, phytoplankton biomass). Thus, the committee disagrees with conclusion (1).
In contrast to this review in the Atkins report, the committee determined that an alternate conclusion on the overall impact of DBOC operations could be reached, with the beneficial effects of shellfish filtration outweighing the adverse impacts from sediment disturbance and the low levels of contaminants generated by DBOC activities.
Soundscapes (p. 81-86)
The Atkins review concluded that the scientific interpretation and analyses in the DEIS are reasonable, supported by the available data, and adhere to standard techniques and metrics. The committee agrees with the following comments made in the Atkins review:
- The section on basic acoustics and concepts was well written and comprehensible to a broad audience (with the exception that the definition of dBA was incorrect);
- The DEIS provides a good review of the effects of noise on wildlife “basic life functions” referencing key papers. Several new studies have emerged in the last two years that point to more evidence that noise negatively impacts wildlife;
- There is evidence that noise detracts from a positive park visitor experience and noise generated by DBOC activities negatively affects the human wilderness experience;
- Noise maps (spatial-temporal) of DBOC sound sources would be beneficial for explaining impacts on human and wildlife acoustic space;
- Alternatives B and C are likely to have the same level of impacts on soundscapes; and
- More supporting information is needed for assumptions about nighttime versus daytime ambient noise and propagation.
The committee disagrees with the following conclusions of this section of the Atkins report:
- The evidence presented in the DEIS is “robust.” The committee concludes that the acoustic data, which were collected for other purposes, are not adequate to provide information on (1) spatial-temporal natural sounds, and (2) DBOC levels of noise from various activities and other transient human-related sounds (e.g., air flights, kayakers, etc.).
- L50 is an adequate measure of noise. L50 does not capture high and low extreme values of the amplitude of noise to provide adequate context (range and variability) of noise sources. To characterize the statistical properties of noise in a given environment, a number of measures should be presented.
- Table 3-3 of the DEIS “shows noise level values within close proximity to DBOC noise sources.”1 In reality, several of these values are reported from a 1995 study (Noise Unlimited, Inc., 1995). Apparently, the Atkins reviewer misinterpreted these as in situ data. Table 3-3 data are not from DBOC noise sources at the site and may not be representative of DBOC sound sources.
- The committees disagrees that there is sufficient evidence presented to conclude that alternatives B and C have “major” impacts (Atkins, p. 85). The committee disagrees with the statement that alternative D would have a “greater” (Atkins, p. 85) impact on soundscapes than alternatives B or C. For example, a new building could be constructed to reduce noise from onshore DBOC operations and mitigation measure are available that could reduce noise associated with motorboat activity.
The committee identified additional shortcomings in the DEIS that were not mentioned by this review, including a lack of underwater soundscape assessments (underwater acoustic data collection). Also, the Atkins review did not mention that additional relevant information was available in the Volpe (2011) study that was not included in the DEIS analysis.
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1 DEIS, p. 204.
Socioeconomics
The review states that the DEIS does not embody the best available science on socioeconomic impacts. This review identified major short-comings of this section and concludes that “the methods used … do not follow accepted economic impact analysis practice.” The review also noted: “Economic impacts are assessed using qualitative judgments instead of quantitative measurements leading to unsubstantiated inferences and interpretations of impacts that are difficult to judge reasonable.” The committee agrees with the review and also finds the section on socioeconomic impacts seriously deficient (see Chapter 3).