Frequently Asked Questions about Bristol Bay Assessment
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
History and Authority
Why did EPA conduct this assessment? Why now, before it has received a mine proposal?
What is the scope of the Bristol Bay Assessment?
Has EPA ever done an assessment like this before?
What authority is EPA using for its watershed assessment?
What is Clean Water Act Section 404(c)?
Science and Peer Review
What does the assessment say about the Bristol Bay fishery?
What kind of information did EPA collect and analyze for the assessment?
How did the assessment change between the May 2012 draft and the April 2013 draft?
How did the assessment change between the April 2013 draft and the final assessment?
Did EPA use data from the Pebble Limited Partnership?
How were the peer reviewers selected?
What areas of expertise are relevant to the peer review and were sought for members of the peer review panel?
Who were the peer review panel members?
Why did EPA conduct a peer review of this assessment?
Responding to Peer Review and Public Comments
Q: Why did EPA conduct this assessment? Why now, before it has received a mine proposal?
A: EPA initiated this assessment in response to petitions from nine federally recognized tribes and other stakeholders who asked us to take action to protect Bristol Bay’s salmon populations. They expressed concern that the Bristol Bay salmon fishery would be at risk from the potential Pebble Mine.
We also heard from other tribes and stakeholders who support development in the Bristol Bay watershed and have requested EPA take no action and allow a typical permitting process to proceed.
EPA performed this assessment to better understand the watershed and its resources. The final assessment will be valuable to the public and for federal, state, and tribal governments as they consider how best to address the challenges of mining and ecological protection in the watershed.
Q: What is the scope of the Bristol Bay Assessment?
A: This scientific assessment focused on the Nushagak and Kvichak River watersheds in Bristol Bay, which are open for large-scale resource development. We examined current environmental conditions and possible short-term and long-term impacts of large-scale mining.
EPA reviewed existing scientific studies and data. The agency focused specifically on potential impacts to salmon because of their ecological, economic, and cultural importance in the region. The assessment also looked at how impacts to salmon could affect indigenous subsistence cultures and wildlife.
Q: Has EPA ever done an assessment like this before?
A: Conducting scientific assessments is part of EPA’s mission and day-to-day work. EPA has conducted assessments that examine environmental impacts of past actions or potential impacts of future actions, including studies that:
- Predict the future introduction of non-indigenous species to the Great Lakes
- Assess the effects of mountaintop mines and valley fills on aquatic ecosystems in the Central Appalachian Coalfields
- Explore the environmental impacts of human activities in the Waquoit Bay watershed in Massachusetts.
Q: What authority is EPA using for its watershed assessment?
A: EPA conducted this assessment under its Clean Water Act authorities, including Sections 104(a) and (b), which, among other things, direct the agency to:
…conduct and promote the coordination and acceleration of, research, investigations, experiments, training, demonstrations, surveys, and studies relating to the causes, effects, extent, prevention, reduction, and elimination of pollution.
Q:What is Clean Water Act Section 404(c)?
A: Clean Water Act Section 404(c) authorizes EPA to prohibit the specification of any defined area as a disposal site, or to deny or restrict the use of any defined area for specification as a disposal site for dredged or fill material if the discharge will have an unacceptable adverse effect on municipal water supplies, shellfish beds and fishery areas, wildlife, or recreational areas. This assessment was not completed as part of any ongoing Section 404(c) or other regulatory action.
Q: What does the assessment say about the Bristol Bay fishery?
A: Key statistics on Bristol Bay’s productivity and economics:
- Bristol Bay supports the largest sockeye salmon run in the world, producing nearly 50 percent of the world’s wild sockeye.
- The annual average run of sockeye in Bristol Bay was approximately 37.5 million fish between 1990 and 2009. In 2009, Bristol Bay’s wild salmon ecosystem generated $480 million in direct annual economic expenditures in the region and sales per year and provided employment for over 14,000 full and part-time workers.
- All five species of Pacific salmon spawn and rear in the Bristol Bay watershed: sockeye, coho, Chinook, chum and pink. In addition, the Nushagak River supports one of the world’s largest Chinook salmon runs.
- The Bristol Bay watershed also provides habitat for 29 fish species, more than 190 bird species, and more than 40 terrestrial mammal species.
- The Bristol Bay watershed supports large carnivores that depend on salmon, such as brown bears, bald eagles, and wolves; ungulates such as moose and caribou; and numerous waterfowl species.
Q: What kind of information did EPA collect and analyze for the assessment?
A: EPA reviewed existing science and information on:
- Bristol Bay salmon and other fish
- Bristol Bay wildlife
- Bristol Bay marine resources
- Salmon fishery economics
- Geology, hydrology, seismology and other environmental sciences
- Wetlands ecology and stream ecology
- Mine engineering, construction and operation
- Subsistence use
- Cultural importance of salmon
- Mining industry practices that minimize mining impacts
- Traditional ecological knowledge from tribal Elders
Q: How did the assessment change between the May 2012 draft and the April 2013 draft?
A: We revised the May 2012 draft assessment in response to the September 2012 peer review report, as well as the public comments we had received to that point. In doing so, we:
- Reorganized the report to better reflect the ecological risk assessment approach and to clarify the purpose and scope of the assessment.
- Refined the mine scenarios and explained how they are based on worldwide industry standards for porphyry copper mining and spe¬cific preliminary mine plans submitted to state and federal agencies related for the Pebble Mine project.
- Incorporated modern conventional mining practices into mine scenarios and clarified that projected impacts assume those practices are in place and working properly.
- Added a smaller mine scenario to represent a worldwide median size mine.
- Added a more detailed mine site water balance analysis.
- Added an analysis of drainage of waste rock leachate to streams.
- Incorporated a more detailed analysis of water loss and water quality on stream reach lengths and fish densities.
- Added an appendix evaluating potential compensatory mitigation measures (Appendix J).
Q: How did the assessment change between the April 2013 draft and the final assessment?
A: There were no revisions that changed the basic conclusions of the assessment. In response to additional comments from the public and peer reviewers, the following revisions improved the completeness and accuracy of the assessment:
- Considered risks from cyanide and molybdenum releases.
- Revised tailings dam failure scenarios which resulted in slightly less severe downstream impacts.
- Considered risks from spillway releases from tailings storage facilities.
- Expanded discussion on potential compensatory mitigation measures (Appendix J).
- Incorporated updated digital elevation model data which changed the areas of impacted streams and wetlands slightly.
- Deleted minor supporting references that were questioned during the public comment period.
Q: Did EPA use data from the Pebble Limited Partnership?
A: Yes. The assessment uses data from the Pebble Limited Partnership and cites the Environmental Baseline Document approximately 70 times. We also used a preliminary mine plan published by Northern Dynasty Minerals titled “Preliminary Assessment of the Pebble Project, Southwest Alaska” (Ghaffari et al, 2011). We also relied on the State of Alaska’s Anadromous Water Catalog which includes fish data collected by Pebble Limited Partnership.
Q: How were the peer reviewers selected?
A: Consistent with guidelines for the peer review of highly influential scientific assessments, EPA asked an independent contractor (Versar, Inc.) to assemble a group of experts to evaluate the May 2012 draft of the Bristol Bay Assessment. Versar evaluated 68 candidates nominated by the public and sought other experts to complete the peer review panel. Twelve scientists, with expertise in mine engineering, salmon fisheries biology, aquatic ecology, aquatic toxicology, hydrology, wildlife ecology, and Alaska Native cultures, reviewed the assessment for its scientific quality. These reviewers were selected based on a variety of factors, including: demonstrated expertise through relevant peer-reviewed publications, absence of conflicts of interest, and willingness to commit adequate time for a thorough review of the draft assessment. During their review of the draft assessment, they specifically addressed 14 charge questions developed by EPA with input from the public.
Q: What areas of expertise are relevant to the peer review and were sought for members of the peer review panel?
A: Potential nominees with expertise in one or more of the following areas were solicited: (1) metals (particularly porphyry copper) mining, (2) salmon fisheries biology, (3) surface, subsurface, or watershed hydrology, (4) aquatic ecology, (5) biogeochemistry, (6) seismology, (7) ecotoxicology, (8) wildlife ecology, and/or (9) indigenous Alaskan cultures.
Q: Who were the peer review panel members?
A: The twelve peer review panel members and their areas of expertise are:
- Mr. David Atkins, Watershed Environmental, LLC. (Expertise in mining and hydrology)
- Mr. Steve Buckley, WHPacific (Expertise in mining and seismology)
- Dr. Courtney Carothers (Expertise in indigenous Alaskan cultures)
- Dr. Dennis Dauble, Washington State University (Expertise in fisheries biology and wildlife ecology)
- Dr. Gordon Reeves, USDA Pacific Northwest Research Station (Expertise in fisheries biology and aquatic biology)
- Dr. Charles Slaughter, University of Idaho (Expertise in hydrology)
- Dr. John Stednick, Colorado State University (Expertise in hydrology and biogeochemistry)
- Dr. Roy Stein, Ohio State University (Expertise in fisheries and aquatic biology)
- Dr. William Stubblefield, Oregon State University (Expertise in aquatic biology and ecotoxicology)
- Dr. Dirk van Zyl, University of British Columbia (Expertise in mining and biogeochemistry)
- Dr. Phyllis Weber Scannel (Expertise in aquatic ecology and ecotoxicology)
- Dr. Paul Whitney (Expertise in wildlife ecology and ecotoxicology)
Q: Why did EPA conduct a peer review of this assessment?
A: Peer review is the evaluation of a product by experts in that field who were not involved in that product's development. EPA employs independent expert peer review for science products to ensure that products are of high quality and are based upon sound science.
Q: How did EPA develop its mining scenarios?
A: EPA developed a series of realistic mining scenarios based on a preliminary mine plan published by Northern Dynasty Minerals titled “Preliminary Assessment of the Pebble Project, Southwest Alaska” (Ghaffari et al, 2011), as well as other mining industry references and consultation with mining experts. The mine scenarios depict modern permitted mines operating in compliance. Eventual mine plans may differ, but would still have the basic elements – a mine pit and large quantities of waste rock and tailings that would have to be managed and stored in perpetuity.
Q: How could mining affect the Bristol Bay salmon fishery?
A: Some of our key findings regarding salmon and mining include:
- Routine Operation
- Mine Footprint
- Depending on the size of the mine, EPA estimates 24 to 94 miles of salmon-supporting streams and 1,300 to 5,350 acres of wetlands, ponds, and lakes would be destroyed.
- EPA estimates an additional 9 to 33 miles of salmon-supporting streams would experience altered streamflows likely to affect ecosystem structure and function.
- Waste and Wastewater Management
- Extensive quantities of mine waste, leachates, and wastewater would have to be collected, stored, treated and managed during mining and long after mining concludes.
- Consistent with the recent record of similar mines operating in the United States, polluted water from the mine site could enter streams through uncollected leachate or runoff, in spite of modern mining practices. Under routine operations, EPA estimates adverse direct and indirect effects on fish in 13 to 51 miles of streams.
- Mine Footprint
- Accidents and Failures
- Wastewater Treatment Plant: Short- and long-term water collection and treatment failures are possible. Depending on the size of the mine, EPA estimates adverse direct and indirect effects on fish in 48 to 62 miles of streams under a wastewater treatment failure scenario.
- Transportation Corridor: A transportation corridor to Cook Inlet would cross wetlands and approximately 64 streams and rivers in the Kvichak River watershed, 55 of which are known or likely to support salmon. Culvert failures, runoff, and spills of chemicals would put salmon spawning areas in and near Iliamna Lake at risk.
- Pipeline: Consistent with the recent record of petroleum pipelines and of similar mines operating in North and South America, pipeline failures along the transportation corridor could release toxic copper concentrate or diesel fuel into salmon-supporting streams or wetlands.
- Tailings Dam: Failure of a tailings storage facility dam that released only a partial volume of the stored tailings would result in catastrophic effects on fishery resources.
Q: How did the EPA involve the Public?
A: In the beginning of the assessment process, we asked the public to send us information on the Bristol Bay environmental resources. Throughout the process, EPA met with numerous groups and heard their concerns and ideas. We produced two drafts of the assessment and requested public comment on both drafts. We asked the public for input on peer reviewers and peer review questions.
Q: How many comments did EPA receive?
A: EPA received approximately 233,000 comments on the first draft and approximately 890,000 comments on the second draft. We heard spoken comments at eight public meetings during the first comment period, attended by approximately 2,000 people. We reviewed and considered ALL comments received during the public comment periods.
Q: What did the public comments say?
A: It is difficult to generalize. We received a large number of comments and they addressed many different aspects of the assessment. Some comments were very general and some provided specific information and suggestions about the assessment. Most of the comments were supportive of our assessment, some were not. Some commenters thought that we overstated the risks from mining; others thought that we understated the risks. Many provided suggestions for improvement to the information in the assessment; some provided new technical and scientific information. EPA reviewed and considered all comments as we revised the assessment. We will release a response to the public comments so commenters can see how we considered their comments.
Q: How many meetings did EPA hold?
A: EPA staff has participated in dozens of meetings with Alaska Native tribes, businesses, stakeholders and communities over the past two years.
Q: How did EPA respond to the comments provided by the peer reviewers and the public?
A: EPA has developed and released a document that includes all peer review comments on both the May 2012 and April 2013 drafts of the assessment, as well as EPA’s responses to these comments. EPA has also prepared detailed Response to Comments documents for the approximately 233,000 public comments submitted (by the comment period deadline) on the May 2012 draft assessment and for the approximately 890,000 public comments submitted (by the comment period deadline) on the April 2013 revised draft assessment. These Response to Comments documents will be released soon.
Below is a synopsis of some of the most frequently raised public comments and EPA’s responses to these comments:
Comment: Many commenters raise concerns that a large mine in the Bristol Bay watershed would generate a large amount of contaminated waste over the long term, which would threaten the salmon fishery. These commenters feel that no level of environmental review or comprehensive mitigation could eliminate the great risk associated with pursuing large-scale mining in this area.
Response: Among the risks identified in the assessment is that extensive quantities of toxic waste and wastewater would have to be successfully collected, stored, and treated. The waste would have to be managed during mining and long after mining ends.
Comment: Commenters assert that the Bristol Bay commercial salmon fishery is the largest, most diverse, and most sustainably-managed wild salmon fishery in the world. Because these commenters feel the Bristol Bay salmon fishery is a valuable resource, they believe it should be protected.
Response: The assessment highlights the ecological, economic, and cultural importance of the Bristol Bay watershed’s fishery resources. The assessment notes, among other findings, that Bristol Bay supports the largest sockeye salmon run in the world, producing nearly 50 percent of the world’s wild sockeye and that the Nushagak River supports one the world’s largest Chinook salmon runs. The assessment does not recommend policy or regulatory decisions.
Comment: Some commenters argue that the assessment is based upon a hypothetical mine that would never be permitted or built.
Response: EPA’s mine scenarios are based upon current industry practices for porphyry copper mining and information specific to the Pebble deposit provided by Northern Dynasty Minerals Ltd. The mine scenarios evaluated in the assessment are based on preliminary mine plans submitted by Northern Dynasty Minerals to the U.S. Securities and Exchange Commission in 2011 and the State of Alaska in 2006. The mine scenarios in the assessment also utilize nearly a decade’s worth of environmental baseline data collected by the Pebble Limited Partnership at the Pebble deposit site. The smallest mine scenario used in the assessment was defined as the worldwide median size porphyry copper mine. Other mine sizes used in the scenario were taken directly from Northern Dynasty Minerals documents. The scenarios evaluated in the assessment realistically represent the type of development plan that could be anticipated for a porphyry copper deposit in the Bristol Bay watershed.
Comment: The traditional, subsistence lifestyle of many Bristol Bay residents is frequently discussed in the comments. Commenters state that their livelihood depends on the region’s salmon resources, which in turn depend on a healthy environment. They indicate that by protecting the watershed, these traditional ways of life could be preserved.
Response: The assessment highlights the economic, cultural, social, and spiritual importance of the Bristol Bay watershed’s fishery resources to the region’s residents. The assessment also evaluated how impacts to the salmon fishery could impact Alaska Native cultures and wildlife in the watershed.
Comment: Many commenters assert that the assessment characterizes the value and diversity of Bristol Bay’s wildlife and fishery, and accurately demonstrates that large-scale mining poses a long-term risk to the area due to the potential for catastrophic failures and long-term habitat degradation.
Response: No response necessary.
Comment: Some commenters argue that EPA should wait for a mine plan to be submitted from mine proponents.
Response: A specific mine plan will not change the major components included in the assessment. Nearly all porphyry copper mines in existence include surface mining, a pit of some size, the removal of waste rock, waste disposal, and a transportation corridor. A specific mine plan is not likely to change these basics. It may change the specific location of the mine components, resulting in different footprint impacts. Changes to the mine footprint may both increase and decrease the estimates provided in the assessment. The assessment does not preclude any mine proponent from submitting a mine plan and Clean Water Act Section 404 permit application to the U.S. Army Corps of Engineers for review and consideration. Active exploration in support of large-scale mining has been underway in the Bristol Bay watershed for over a decade prompting many questions from residents regarding the potential impacts of large-scale mining, particularly on the Bay’s valuable fishery resources. The assessment helps provide answers to these questions.
Comment: Commenters frequently request that EPA use its authority under Section 404(c) of the Clean Water Act to proactively protect the Bristol Bay watershed. Commenters advocating EPA action contend that the assessment documents the value of the area and provides compelling evidence that large-scale mining would have unacceptable adverse effects on the environment, providing support for a 404(c) action.
Response: The assessment is a scientific report and does not recommend policy or regulatory decisions.
Comment: Many commenters note that the assessment results did not consider all possible impacts.
Response: This was noted by many who wanted the assessment to take a broader approach. For example, many wanted the assessment to look at the direct impacts of mining on people and wildlife, rather than just focusing on how impacts to salmon could indirectly impact people and wildlife. Many also wanted the assessment to evaluate all of the infrastructure associated with constructing a large-scale mine in the region, including a deep-water port on Cook Inlet, a large power plant and associated transmission lines, all mine processing and operational facilities, etc. We selected fish, and specifically salmon and other salmonids, as our primary assessment endpoint because of their critical importance to stakeholders and future decision making in the watershed.
Comment: Some commenters indicate that potential impacts are exaggerated, while others argue that potential impacts are understated.
Response: Public comments concerning the risks from mining presented in the assessment were mixed. Some comments suggested that risks were exaggerated, and that modern mining design, technology, practices, and mitigation measures would reduce these risks. Other comments suggested that risks were understated because the assessment did not consider the effects of all the likely components of a mine project, the extent of wetlands and streams and fish distributions were underestimated, and many of EPA’s assumptions regarding impact mitigation strategies were overly optimistic. Throughout the development of the assessment, EPA was careful to present a balanced view of potential impacts and avoid both “worst-case” and “best-case” evaluations. Where possible, the assessment includes upper and lower bounds for potential failures and risks. Severe but realistic accident and failure scenarios are analyzed because they bound the reasonable range of risks. Further, EPA was very careful to describe the effects of accidents, failures and routine operations and the probabilities that these effects would occur and make a clear distinction between the two.
Comment: Some commenters argue that the assessment is not needed and that the typical Environmental Impact Statement (EIS) conducted pursuant to the National Environmental Policy Act (NEPA) is all that is needed. They argue that the assessment and potential Clean Water Act Section 404(c) actions would undermine existing regulatory processes, thereby setting a dangerous precedent for future projects.
Response: The assessment was conducted to inform EPA following requests from multiple stakeholders. The assessment is a scientific investigation. No judgments are made concerning future actions and no policy or regulatory options are presented or analyzed. The assessment informs EPA, other government entities, and the public about the biological and mineral resources of Bristol Bay watershed and the potential impacts of large scale mining. It expands understanding of the watershed and the potential impacts of mining. This information is useful to better inform dialogue among all interested resources. The assessment does not preclude assessment under NEPA—rather, it will enhance and enrich a NEPA process.
Comment: Some commenters argue that EPA did not consider modern mining mitigation practices that would minimize all potential impacts from the mine.
Response: Modern conventional mining mitigation technologies and practices were included in the May 2012 draft of the assessment; however, they were discussed primarily in an appendix. Discussion of how modern conventional mining mitigation technologies and practices were incorporated in the assessment was clarified and expanded in both the April 2013 revised draft assessment and the final assessment. The assessment is careful not to use novel or experimental mitigation measures in the mining scenarios as those do not have a demonstrated record of success. No mitigation practices will eliminate the footprint impacts of a large scale mine and the assessment indicates that compensatory mitigation for wetland and stream losses would be technically challenging and ecologically questionable.
Comment: Some commenters argue that potential impacts on fish habitats are minor when compared with the size of the Bristol Bay watershed.
Response: Even though the mine footprints alone would result in the loss of hundreds to thousands of acres of high-functioning wetlands and tens of miles of salmon-supporting streams, some have argued that this is a tiny percentage of the overall fish habitat in the entire Bristol Bay watershed that can be lost without harm and/or “replaced”. Fishery science suggests that losses of habitat can impact overall habitat diversity of a watershed. Changing the “portfolio” of biocomplexity (i.e., salmon genetic, behavioral, and phenotypic variation) and the diverse habitat upon which biocomplexity develops can reduce the overall reliability of the fishery. Research on the Bristol Bay salmon fishery argues that the fish returns to an individual river are dependent on the contributions by individual tributary streams.
Comment: Some commenters argue that habitat impacts could not be linked to impacts on fish populations.
Response: Habitat losses could not be quantitatively linked to impacts on fish populations because of an absence of data for the entire watershed. Although there are data on salmon occurrence, what is lacking are data on salmon abundances, productivities, life-stage specific information and limiting factors for all parts of the watershed. These data do not exist and would take many years to collect. Estimated effects of mining on fish habitat, including losses due to water contaminants, thus become the surrogate for estimated effects on fish populations.