Thank you, Curt, for making those points, especially the ones about this study's failure to directly address dredging's impact on fish and the release of toxic heavy metals from streambeds, which dredging is unable to capture completely.

The following is a good short summary of the downsides of suction dredging. At the bottom of the piece are additional links describing the ultimately successful effort in Oregon to limit dredging's damage to streams with wild fish.

http://www.cascwild.org/campaigns/save-o...nking-for-gold/