Suction dredging is a generally noisy, environmentally damaging practice that involves moving bed-load sediment in a river or stream from one location to another. Gasoline or diesel motors are mounted on top of rafts, and attached to hoses or vacuums that suck up the bed of a gravel stream before being discharged out the other end. It results in river bottoms stripped of sand and gravel, degraded spawning beds for wild steelhead, salmon and bull trout and loss of habitat for insects, which provide food for various fish species.
Other concerns include air and water quality, soil impacts, noxious weed infestations, impacts to in-stream fish habitat components (such as downed woody debris and boulders) and new routes pioneered to drive dredging equipment to stream banks. Dredging negatively affects benthic invertebrates, especially mollusks, which disperse slowly, and mussels whose populations are currently unstable.
There has been a rapid rise of suction-dredge mining operations in designated areas of Orogrande and French Creeks (tributaries of the N. Fork) and along the South Fork of the Clearwater River. There are over two dozen unpatented mining claims on the Orogrande and French Creeks and over three dozen on the South Fork of the Clearwater River. 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 recently enacted regulations dictating when, where and how much dredging can occur on a particular stretch of water. Dredging also requires a permit through the state of Idaho and a federal permit from the Environmental Protection Agency (Clean Water Act). The legal requirement to obtain permits has not stopped certain individuals from dredging illegally along the S. Fork Clearwater.
Suction dredge mining was recently banned in California due to negative impacts to salmon habitat. In January 2016, the state of Oregon put a moratorium in place for all suction dredge mining operations until further notice. In 2017, a lawsuit was filed in the state of Washington to hault the unregulated permitting of suction-dredge mining on the state’s waterways.