The Four Rs of Environmental Dredging: Resuspension, Release, Residual, and Risk, January 2008

A workshop sponsored by the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency was held at the U.S. Army Engineer Research and Development Center, Waterways Experiment Station, in Vicksburg, MS, in April of 2006. Fifty experts from government, the private sector, and academia participated in the workshop, which focused on four issues (the four Rs) relevant to environmental dredging: (1) sediment resuspension resulting from dredging operations, (2) release of contaminants from bedded and suspended sediments in connection with dredging, (3) residual contaminated sediment produced by and/or remaining after dredging, and (4) the environmental risks that are the target of and associated with dredging. Goals for the workshop were to: (1) promote consistency in the terms used to define the challenges represented by the four Rs, (2) develop consensus for a conceptual model that relates the relevant processes, (3) identify current resources and needs regarding data and methods/models to better describe and understand the processes, and (4) identify key uncertainties and make recommendations regarding future research to resolve those uncertainties. This technical report summarizes analysis and synthesis of the results of the workshop. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.