Turbidity Caused by Dredging; Viewed in Perspective

Over the past decade there has been increasing awareness of the environmental impact of dredging, and in particular, one of the side effects receiving attention was the extra turbidity of resuspended waterbed material occurring whilst dredging. With the help of environmental impact assessments a great deal of knowledge about ”turbidity caused by dredging” has been acquired in The Netherlands. However many measurements must be considered in order to provide answers to whether or not turbidity has adverse impacts. How a dredging technique is applied is of utmost importance. The background turbidity, collapse times, and resuspension must be considered. But analyses need to be localised and specific to a certain situation. This paper is the result of the work of the project group, Environmental Effects of Dredging, a joint effort of several organisations in dredging-related industries and the Netherlands Government. At present some 35 standardised turbidity measurements have been executed around various dredging techniques. Photographs are used courtesy of Delft Hydraulics.