PROCESS-BASED ESTIMATION OF SEDIMENT RESUSPENSION LOSSES DURING BUCKET DREDGING

摘要

Water quality impacts resulting from dredging operations are of particular current interest. Resulting suspended sediment plumes potentially impact the local aquatic environment in a variety of ways, including the burial of benthic organisms, contaminant transport, negatively affecting recreational uses, and modifying fish behavior. These potential impacts have often been cited in requests for restrictions on dredging operations in the form of environmental windows in many areas of the country and the focus of concern for many remedial dredging operations. While some resuspension data are available and a few empirical tools have been developed to make a priori estimates of sediment resuspension associated with dredging operations, the limited database hampers the applicability of these approaches. Hayes and Wu (2001) proposed the Resuspension Factor approach as a simplified approach to estimating sediment resuspension losses during dredging. Recent research has refined that approach by evaluating specific loss mechanisms and developing a generic framework for all types of bucket dredges. While the existing database does not allow sediment resuspension loss models to be developed and calibrated for each loss mechanism, the fundamental approaches presented provide a basis on which to focus future research efforts. Focusing research efforts on specific loss mechanisms holds significantly more promise for eventually developing reliable predictive methods for a wide-array of equipment working under a variety of conditions.