Water Management During Mechanical Dredging of Contaminated Sediment

摘要

The volume of material placed in a barge by a mechanical dredge using a closed bucket will consist of both sediment and water, with the potential for water volumes to equal or exceed the in-situ volume of sediment dredged. Discharging the captured water back to the waterway as barge overflow water will often result in the release of sediment back to the dredged area and the formation of a residual layer of sediment over the dredged surface. There' is also potential for offsite migration of the sediment, producing a residual layer outside the original project area. The average bucket fill factor for a given project is a function of several conditions, including the size and configuration of the bucket, the nature and thickness of the dredge cuts and sediment, and the attributes of the dredge operator. The average bucket fill factor can be used to estimate the amount of water that will produced by a mechanical dredging project, expressed as a function of the in-situ volume of sediment to be dredged.