Equipment and Placement Techniques for Subaqueous Capping

摘要

Dredged material and in situ sediments may contain contaminants at sufficient concentrations to degrade the benthic environment. In cases where unacceptable toxicity or bioaccumulation is predicted to occur, subaqueous capping with a layer of clean material is often an acceptable management or remediation alternative. This technical note (TN) describes equipment and placement techniques for subaqueous capping projects. The equipment and techniques are applicable to placement of contaminated material to be capped and clean material to be used for capping and include conventional discharge from barges, hopper dredges, and pipelines; submerged discharge from diffusers and tremies; and surface spreading techniques for cap placement. Both granular capping materials such as sediments and soils and geosynthetic fabrics and armoring materials are considered.