Many of these recreational dredgers save the mercury they have recovered, which if left behind may have caused harm to fish or other wildlife. Those same fish prefer to spawn in deep pools within those rivers and streams. Another one of the residual benefits of recreational dredging is small pools where the dredging had taken place. These pools are not going to change the course of the river, and will fill in naturally as the water flow increases during spring runoff. Dredging is seasonal, and is regulated by the flow of the water during certain seasons.
Dredgers also stop all activities during spawning seasons to leave the fish unharassed.
Impacted soil on the river bottoms is loosened by dredging making those rivers better spawning and feeding grounds for native fish. Prospecting clubs all over the United States are working to share information with the public concerning the safety of modern day prospecting. It's hard being blamed for the mistakes of the past, and it really isn't necessary. What we do as recreational prospectors has nothing to do with what our forefathers did 150 years ago when they thought the West was disposable land never to be used for anything but gathering riches in gold, and then left behind. Our club has done many cleanup projects along those same rivers and streams that the old timers had left in such a mess.