EPA 910-R-14-001ES | January 2014 An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska Executive Summary Region 10, Seattle, WA www.epa.gov/bristolbay Executive Summary Tributary of Napotoli Creek, near the Humble claim Photo: Michael Wiedmer he Bristol Bay watershed in southwestern Alaska supports the largest Tsockeye salmon fishery in the world, is home to 25 federally recognized tribal governments, and contains significant mineral resources. The potential for large-scale mining activities in the watershed has raised concerns about the impact of mining on the sustainability of Bristol Bay’s world-class commercial, recreational, and subsistence fisheries and the future of Alaska Native tribes in the watershed, who have maintained a salmon-based culture and subsistence-based way of life for at least 4,000 years. The U.S. Environmental Protection Agency (USEPA) launched this assessment to determine the significance of Bristol Bay’s ecological resources and evaluate the potential impacts of large-scale mining on these resources. It uses the well-established methodology of an ecological risk assessment, which is a type of scientific investigation that provides technical information and analyses to foster public understanding and inform future decision making. As a scientific assessment, it does not discuss or recommend policy, legal, or regulatory decisions, nor does it outline or analyze options for future decisions. 1 The Lower Nushagak River between Portage Creek and Ekwok Photo: Michael Wiedmer This assessment characterizes the biological and mineral resources of the Bristol Bay watershed. It is intended to increase understanding of potential impacts of large- Lake Clark scale mining on the region’s fish resources National Park and Preserve and serve as a technical resource for the r e KVICHAK rk r a iv l e C R v e public and for federal, state, and tribal i k a a R L!( n k t a a e Wood-Tikchik g a Riv r Port Alsworth h litn governments as they consider how best to a c C hu l State Park h NUSHAGAK u s u M Ko Nuy kt r Togiak akuk N u e Riv l v !( address the challenges posed by mining er i R i Nondalton National i R ve r n Wildlife ^ e l a Refuge oli Creek S h and ecological protection in the Bristol Bay Napot Koliganek tu Pedro Ba!(y y w !( a r I!(liamna hok Rive e N !( Klutu k C Newhalen watershed. It will inform ongoing discussions re K e o k kw o New Stuyahok Iliamna Lake k R !( of the risks of mine development to the ive r !( !( Kokhanok Aleknagik W Ekwok !( !( sustainability of the Bristol Bay salmon o r o e d v ver Igiugig i i R k R R ha i ic v k v e fisheries and thus will be of value to the many a K r g !( Katmai Cook Inlet !( a h er s Levelock Riv National Park u Al ak stakeholders in this debate. Dillingham agn and Preserve N !( Portage Creek The assessment also will inform the consideration of options for future government action, including, possibly, Bristol Bay by USEPA, which has been petitioned by multiple groups to address mining activity in the Bristol Bay watershed using its authority under the Clean Water Act (CWA). Approximate Pebble Deposit Location Should specific mine projects reach the 0 25 50 Towns and Villages Kilometers permitting stage, the assessment will enable 0 25 50 Parks, Refuges, or Preserves Miles state and federal permitting authorities to Watershed Boundary make informed decisions to grant, deny, or condition permits and/or conduct additional 2 The Nushagak River and Kvichak River Watersheds of Bristol Bay KVICHAK NORTH FORK KOKTULI UPPER TALARIK r e v NUSHAGAK i R i l u t k o K K k o r k o t F u l h i r t R No iv Present er SOUTH FORK KOKTULI Spawning r tuli Rive Kok k Rearing rk e Fo re South C ri k la Pebble 6.5 Components Ta r e p p Mine Scenario Watersheds U Watershed Boundary 0 2.5 5 Kilometers 0 2.5 5 Miles Iliamna Lake Iliamna Lake Reported Salmon (Sockeye, Chinook, Coho, Pink, and Chum Combined) Distribution in the South and North Fork Koktuli River and Upper Talarik Creek Watersheds. Designation of species spawning, rearing, and presence is based on the Anadromous Waters Catalog (Johnson and Blanche 2012). Life-stage- specific reach designations are likely underestimates, given the challenges inherent in surveying all streams that may support life-stage use throughout the year. Figure ES-2. Reported salmon (sockeye, Chinook, coho, pink, and chum combined) distribution in the South and North Fork Koktuli Rivers and Upper Talarik Creek watersheds. Lake Clark Designation of species spawning, rearing, and presence is based on the Anadromous Waters Catalog. Life- National Park and Preserve stage-specific reach designations are likely underestimates, given the challenges inherent in surveying all r research or assessment as a basis for these fisheries are expected to affect e KVICHAK rk streams that may support life-stage use throughout the year. r a iv l e C R v e i k a a R L!( the abundance and health of wildlife n such decisions. USEPA conducted this k t a a e Wood-Tikchik g a Riv r Port Alsworth h litn a c C u l h State Park h NUSHAGAK populations. Alaska Native cultures have u s u assessment consistent with its authority M Ko Nuy kt r Togiak aku N u e k Riv v !( er li R i Nondalton National i R strong nutritional, cultural, social, and ve r n Wildlife ^ e under the CWA Section 104(a) and (b). l a Refuge oli Creek S h Napot Koliganek tu Pedro Ba!(y spiritual dependence on salmon, so y w !( a r I!(liamna hok Rive e N !( Klutu k C Newhalen changes in salmon fisheries are expected re K e o k k Scope of the Assessment w o New Stuyahok Iliamna Lake to affect the health and welfare of Alaska k R !( ive r !( !( Kokhanok This assessment reviews, analyzes, and Native populations. Therefore, wildlife Aleknagik W Ekwok !( !( o r o e d r v ive Igiugig i R synthesizes information relevant to and Alaska Native cultures are also R k R ha i ic v k v e a K r g !( Katmai Cook Inlet !( a potential impacts of large-scale mine considered as assessment endpoints, but h er s Levelock Riv National Park u Al ak Dillingham agn and Preserve N development on Bristol Bay fisheries and only as they are affected by changes in !( Portage Creek consequent effects on wildlife and Alaska salmonid fisheries. Native cultures in the region. Given the economic, ecological, and cultural The assessment considers multiple importance of the region’s key salmonids geographic scales. The largest scale is the Bristol Bay (sockeye, Chinook, coho, chum, and Bristol Bay watershed, which is a largely pink salmon, as well as rainbow trout undisturbed region with outstanding and Dolly Varden) and stakeholder natural, cultural, and mineral resources. and public concern that a mine could Within the larger Bristol Bay watershed, affect those species, the primary focus the assessment focuses on the Nushagak of the assessment is the abundance, and Kvichak River watersheds. These are productivity, and diversity of these the largest of the Bristol Bay watershed’s fishes. Because wildlife in Bristol Bay are six major river basins, containing about intimately connected to and dependent 50% of the total watershed area, and are on these and other fishes, changes in identified as mineral development areas by the State of Alaska. Given its size and 3 Sockeye salmon near Gibraltar Lake Photo: Thomas Quinn (University of Washington) extent of characterization, the Pebble deposit. The final geographic scale is the deposit is the most likely site for near- combined area of the subwatersheds term, large-scale mine development in between the mine footprints and the the region. Because the Pebble deposit is Kvichak River watershed’s eastern located in the headwaters of tributaries boundary that would be crossed by a to both the Nushagak and Kvichak Rivers, transportation corridor linking the mine both of these watersheds are subject to site to Cook Inlet. potential risks from mining. The third geographic scale is the watersheds of The assessment also addresses two the three tributaries that originate within periods for mine activities. The first is the potential footprint of a mine on the the development and operation phase, Pebble deposit: the South Fork Koktuli during which mine infrastructure would River, which drains the Pebble deposit be built and the mine would be operated. area and converges with the North This phase may last from 20 to 100 years Fork west of the Pebble deposit; the or more. The second is the post-mining North Fork Koktuli River, located to the phase, during which the site would northwest of the Pebble deposit, which be monitored and maintained. Water flows into the Nushagak River via the treatment and other waste management Koktuli and Mulchatna Rivers; and Upper activities would continue as necessary Talarik Creek, which drains the eastern and any failures would be remediated. portion of the Pebble deposit and Because mine wastes would be persistent, flows into the Kvichak River via Iliamna this period could continue for centuries Lake, the largest undeveloped lake in and potentially in perpetuity. the United States. The mine footprints We began the assessment with a in the three realistic mine scenarios thorough review of what is known about evaluated in the assessment make up the Bristol Bay watershed, its fisheries and the fourth geographic scale.