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EPA's Pebble assessment sells Bristol Bay salmon short

  • Author: Carol Woody
  • Updated: September 29, 2016
  • Published July 9, 2013

The science is clear in EPA's recent conservative Bristol Bay Watershed Assessment: Alaskans would trade our sustainable salmon resources for a nonrenewable, privately owned mineral resource and a highly risky perpetual waste and catastrophic threat management problem.

My gripe with the EPA assessment is it underestimates impacts of industrial development to salmon, probably by magnitudes, by not considering:

• Exploitation of Pebble's estimated 10.8 billion-ton deposit,

• Impacts of power plants and mine fuel needs,

• Impacts of urban development and infrastructure,

• Impacts of mine water draw down on streams,

• Realistic impacts of culverts and roads,

• Realistic impacts of accidents, pipeline spills and treatment plant spills.

Although conservative, EPA estimates that development of a 6.5 billion-ton mine, just 60 percent of Pebble, could eliminate 90 stream miles and 22 salmon stream miles; reduce flows and thus fish production in 34 more miles; have toxic effects on fish in 35 stream miles; have toxic effects on fish prey in more than 50 stream miles; and eliminate 4,800 acres of wetlands affecting quality and quantity of salmon habitat. These estimates are just for the mine footprint. Estimated impacts to habitat and salmon only increase when the access road is considered, as well as development of the additional mines that surround Pebble.

Northern Dynasty (NDM), a 50-percent partner in Pebble, slammed EPA's assessment because it didn't consider some mitigation techniques to offset salmon losses from eliminated habitat. The mine partners propose to add wood and boulders as well as bulldoze new channels in what are now some of the world's most productive salmon rivers. They presume habitat limits salmon production and claim that the success of such manipulations are "settled science." However, such manipulations are generally only done in highly impacted rivers that require rehabilitation to even approach pre-disturbance productivity. River restoration, a billion-dollar-a-year business, is rarely monitored more than a few years, enhancements only endure a decade or two, and there are no studies showing increased salmon production at the watershed scale.

Northern Dynasty also proposes to mitigate stream flow reductions that would harm salmon by damming more streams, creating ice fields to recharge aquifers, and/or by pumping downstream water upstream for re-release. Such techniques are experimental at best. Do we really want to experiment with Bristol Bay?

Northern Dynasty also proposes to change area water chemistry to "improve productivity and reduce metal toxicity" from the mine. (At least they recognize toxic metals like copper will increase from mining.) But, NDM fails to recognize a basic tenet of salmon life history in that salmon imprint or memorize natal stream chemistry, which enables them to return to and spawn in the streams to which they are adapted. Changing stream chemistry can result in salmon not recognizing their natal streams and straying to streams to which they are not adapted. This can reduce offspring survival and increase pre-spawning adult mortality. One of the biggest issues with Pebble is that perpetual water treatment and waste management will be needed after mining, and how much water chemistry of now productive salmon streams will change is unknown but of great concern. If water quality changes such that salmon are no longer supported, no amount of stream rehabilitation will bring salmon back.

EPA just closed public comments on their Watershed Assessment. While the companies who wish to develop Pebble will find ways to criticize the document on grounds of process, the interests of Bristol Bay requested EPA's work. Moreover, their involvement is part of the established regulatory process and all parties involved should understand what is and is not allowed in the Bristol Bay Watershed. Finally, the science is clear and the record established. We know Bristol Bay boasts the largest most diverse and valuable sockeye salmon runs left on the planet. We also know from the historical record what the potential impacts of large-scale mining are. In short, the science is clear and supports potential regulatory action by EPA. Should EPA use their Clean Water Act authority to restrict large scale mining in Bristol Bay, their actions would be justified by the scientific record.

After all, there are copper deposits all over the world; there is only one Bristol Bay.

Dr. Carol Ann Woody works for the non-profit Center for Science in Public Participation (CSP2) in Anchorage, Alaska. She is past president of the Alaska Chapter of the American Fisheries Society and currently serves with the Western Divisions Environmental Concerns Committee. She has over 25 years of professional experience including 18 years as a federal fisheries scientist.

The views expressed here are the writer's own and are not necessarily endorsed by Alaska Dispatch, which welcomes a broad range of viewpoints. To submit a piece for consideration, e-mail commentary(at)

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