Suction Dredging and Trout

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Suction Dredging and Trout

Postby Richard » Fri Jul 13, 2007 3:23 pm

Below is a letter we received for publication in the July/August 2007 issue of Cal Fly Fisher. We didn't have room to print all of the citiations it contains.

I am a fly fisher who has also been responsible for suction dredge activities, so I carefully read Bill Carnazzo’s “The Middle Fork of the American River” in the March/April ’07 issue. His specific examples of “denuding stream bottoms of gravels” and “leaving sterile bedrock channels” and “downstream siltation” does not agree with my experience, observation and encyclopedia literature references that I can provide about the environmental impact of suction dredging.

There are anglers whose greedy, illegal and unethical practices have overshadowed those of conservationist sportsman in the eyes of those environmentalists who choose not to fish. Even those with the best intentions can have a negative impact, such as the damage to the benthic macroinvertebrate (BMI) populations that legions of wading fly fishers periodically have had on Hat Creek below the powerhouse.

Suction dredging, performed correctly, will remove lead and mercury as well as leave sections of clean gravels on the streambed to improve habitat for spawning trout and salmon and BMIs. No matter how it is performed, suction dredging with current equipment can only move gravels from one part of the stream bed to another and less than one hundred feet (usually far less). For example, I tend to work a 10-foot by 10-foot area, and fill in holes with the gravel and rock that came from them.

Too many legislative actions are being taken with mere anecdotal (if any) evidence, emotion and opinion. It is much easier for politicians to close or restrict access to outdoorsmen than to enforce existing laws and to change practices of utility companies and other big business interests and their impact on our environment. In fact, the greatest abusers of our resources use their financial power to buy exemption credits at our expense (both to the environment and in the loss of our rights).

The streams in Alaska I have dredged have tremendous populations of char, Arctic Grayling, various species of salmon and the environment that sustains these native populations along with intense suction dredging activities that have been ongoing for decades. Other problems must be more detrimental to fish and their habitat.

Bill Carnazzo did offer much information along with his opinion, and it is my hope that more people get involved with issues which impact them, regardless of whether I agree with them or not. Here are the references mentioned above:

CDFG, 1997. draft Environmental Impact Report: Adoption of Amended Regulations for Suction Dredge Mining. State of California, The Resource Agency, Department of Fish and Game

Cooley, M.F. 1995. Forest Service yardage Estimate. U.S. Department of Agriculture, U.S. Forest Service, Siskiyou National Forest, Grants Pass, Oregon.

Griffith, J.S. and D.A. Andrews. 1981. Effects of a small suction dredge and aquatic invertebrates in Idaho streams. North American Journal of Fisheries Management 1:21-28.
Harvey, B.C., K. McCleneghan, J.D. Linn, and C.L. Langley, 1982. Some physical and biological effects of suction dredge mining. Lab Report No. 82-3. California Department of Fish and Game. Sacramento, California.

Harvey, B.C. 1986. Effects of suction gold dredging on fish and invertebrates in two California streams. North American Journal of Fisheries Management 6:401-409.

Hassler, T.J., W.L. Somer and G.R. Stern. 1986. Impacts of suction dredge mining on anadromous fish, invertebrates and habitat in Canyon Creek California. California Cooperative Research Unit, U.S. Fish and Wildlife Office. Humboldt State University. Cooperative Agreement No 14-16-0009-1547.

Huber and Blanchet, 1992. Water quality cumulative effects of placer mining on the Chugach National Forest, Kenai Peninsula, 1988-1990. Chugach National Forest, U.S. Forest Service, Alaska Region, U.S. Department of Agriculture.

Lewis, 1962. Results of Gold Suction Dredge Investigation. Memorandum of September 17, 1962. California Department of Fish and Game, Sacramento, California North, P.A., 1993. A review of the regulations and literature regarding the environmental impacts of suction gold dredging. U.S. Environmental Protection Agency, Region 10, Alaska Operations Office. EP 1.2: G 55/993.

Prussian, A.M., T.V. Royer and G.W. Minshall, 1999. Impact of suction dredging on water quality, benthic habitat, and biota in the Fortymile River, Resurrection Creek, and Chatanika River, Alaska, FINAL REPORT. US Environmental Protection Agency, Region 10, Seattle, Washington.

SNF, 2001. Siskiyou National Forest, Draft Environmental Impact Statement Suction Dredging Activities. U.S. Department of Agriculture, U.S. Forest Service, Siskiyou National Forest, Medford OR.

Somer, W.L. and T.J. Hassler. 1992. Effects of Suction-dredge gold mining on benthic invertebrates in a northern California stream. North American Journal of Fisheries Management 12:244-252.

Stern, 1998. Effects of suction dredge mining on anadromous salmonid habitat in Canyon Creek, Trinity County, California. M.S. Thesis, Humbolt State University, Arcata, CA.

Thomas, V.G. 1985. Experimentally determined impacts of a small suction dredge on a Montana stream. North American Journal of Fisheries Management 5:480-488.

US EPA, 2001. Mercury Recovery from Recreational Gold Miners. ... errec.html

Wanty, R.B., B. Wang, and J. Vohden. 1997. Studies of suction dredge gold placer mining operations along the Fortymile River, eastern Alaska. U.S. Geological Survey Fact Sheet FS-154-97.

Thank you for taking the time to consider another side to this issue.
Ken Templeton

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