THE EVOLUTION OF SUBAQUEOUS CAP DESIGN

摘要

Subaqueous capping is an accepted approach for both the management of contaminated dredged material and the remediation of contaminated sediments. The design of subaqueous caps includes the selection of appropriate capping materials and the evaluation of the required thickness of various cap components. The U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency published technical guidance documents on dredged material capping and in-situ capping in 1998 that described the principle considerations of subaqueous cap design to include consideration of processes related to chemical isolation, physical isolation, bioturbation, erosion, consolidation, and operational factors. Cap design is based on a "layer cake" approach in which various components of the cap are designed to account for the processes pertinent to the site, with the total cap thickness determined as the sum of the cap components. Cap design in recent years has evolved to include consideration of dual functions for cap components, reactive cap materials to increase the effectiveness of the cap for isolation, and components related to habitat enhancement. This paper describes the evolution of subaqueous cap design to include consideration of conventional designs with granular materials, reactive cap materials, and specialized cap components for habitat or other purposes.