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Suction dredge mining

Nick Gerhardt Photo

Dredging is a generally noisy, environmentally damaging practice that involves moving bed-load sediment in a river or stream from one location to another. This is accomplished by mounting gasoline or diesel motors on top of rafts, and attaching hoses or vacuums to suck up the bed of a gravel stream (in search of gold) before much of the material is discharged back into the river.

This results in river bottoms stripped of sand and gravel, loss of habitat for macro-invertebrates, which provide food for various fish species, and degraded spawning beds for wild steelhead, Chinook salmon and Bull trout. Damage to in-stream fish habitat (such as downed/woody debris and boulders) and riparian habitat is very concerning. Dredging also negatively affects benthic invertebrates, especially mollusks, which disperse slowly, and mussels, whose populations are currently unstable. There is also the potential for gasoline/refueling spills and diminished water quality.

There has been a rapid rise of suction dredge mining operations in designated areas of Orogrande and French Creeks (tributaries of N. Fork) and along the S. Fork Clearwater River. There are over two dozen unpatented mining claims on Orogrande and French Creeks, and over three dozen on the S. Fork Clearwater. Suction dredge mining operations are also active in Lolo Creek (tributary of main stem Clearwater) and Moose Creek (tributary of Kelly Creek).

The Nez Perce – Clearwater National Forests enacted dredging regulations (Plan of Operations) after completing an Environmental Assessment in 2015. The Biological Opinion (NOAA Fisheries) included in the assessment concluded that dredging has an adverse impact to threatened fish populations and their habitat, and therefore, regulations must be put into place in order to mitigate impacts and issue permits. These regulations mostly dictate when, where and how much dredging can occur on a particular stretch of river. Dredging operations in Idaho also require a permit through the state of Idaho (Idaho Department Water Resources) and a Clean Water Act permit from the Environmental Protection Agency.

The legal requirement to obtain permits did not stop multiple individuals from dredging illegally along the S. Fork Clearwater in 2018. There were many miners operating illegally during the dredging season (July 15 – August 15) on the S. Fork. Citizen monitoring detailed violations, including miners not having all the necessary permits, unfilled dredge holes, dredges working in close proximity to one another, extensive sediment plumes, dredges operating in pool tailouts, dredges refueled in stream channel, unattended full containers on river bank/riparian areas, and illegal occupancy. To compound the situation, the Forest Service did a completely inadequate job of enforcing its own regulations, and holding individuals accountable to the law.

More News

Washington bans suction dredge mining in certain streams – March 2020.

Oregon bans suction dredge mining in certain streams – September 2018.

California bans suction dredge mining – January 2018.


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