Improvement Of Operations And Maintenance Techniques Program Literature Review And Technical Evaluation Of Sediment Resuspension During Dredging

Maintenance of navigable waterways is essential for continuous traffic flow. The sediments in the waterways have, in many instances, become contaminated resulting in a concern that dredging and disposal of the dredged materials may adversely affect water quality and aquatic animals. Most dredges in the United States are old and not designed to handle highly contaminated sediments. This study is a literature review and technical evaluation of conventional and unconventional dredges, their dredging techniques, factors influencing the sediment resuspension characteristics associated with such dredges, the nature of improvements that have been made in such dredges to reduce their environmental impact, and further research needed in this field. This literature review indicated that all conventional dredges generate turbidity in the vicinity of the dredge to a degree depending on the type of dredge, the nature of sediment, and the dredging and disposal method adopted. The turbidity is usually of a short duration, and normal conditions are quickly restored. The sediment resuspended by dredging may release into the water column some contaminants that affect the environment. Measures such as silt curtains are only partially successful in that these do not eliminate the impact on the benthic community along the bottom. Some unconventional dredging systems appear to be successful in reducing sediment resuspension but are unable to handle large quantities of materials.