The area or length of river or streambed worked by a single suction dredger, as compared to total river length, is relatively small compared to the total available area.” The remaining time is spent working on equipment and processing dredged material. The average number of hours is 5.6 hours per day. A recreational suction dredger (representing 90-percent of all dredgers) may spend a total of four to eight hours per day in the water dredging an area of 1 to 10 square meters. The California Department of Fish and Game (1997) described typical dredging activities as follows’ “An individual suction dredge operation affects a relatively small portion of a stream or river. This approach is entirely inconsistent with the way in which suction dredges operate or generally impact their downstream environment. For example, they would characterize the affects of turbidity from a suction dredge as if it would impact downstream organisms in a manner that system-wide high water flow events might. It has been observed that environmentalists opposing suction dredging use data gleaned from reports that studied effects of environmental perturbations that are occurring on a system-wide basis. GEOGRAPHICAL SCALE OF SMALL-SCALE SUCTION DREDGING But first I would like to put this issue in to perspective. I will focus my water quality comments on these three areas. In water quality terms some studies have discussed turbidity, water temperature, and suspension of heavy metals into the overlying water. In nearly every instance the results have concluded that the effects were less than significant. Thank you for allowing me this opportunity to comment on the water quality aspects of small-scale suction dredge mining.Īs I have searched the scientific literature for studies on the effects of small-scale suction dredge mining on the environment I have learned that the preponderance of the published research studies have been directed towards assessment of its effect on the biology of the streams and rivers. Box 100 Sacramento, California 95812-0100 Fax: 91 email address is being protected from spam bots, you need Javascript enabled to view it State Water Resources Control Board Division of Water Quality P.O. A Good Read On The Effects Of Suction Dredging
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