When dredged materials proposed for open-water placement are found to require isolation form the benthic environment due to the presence of contaminants, capping may he appropriate for consideration as a management action. This report is intended to provide technical guidance for evaluation of capping projects. From a technical perspective, this guidance is applicable to dredged material capping projects in ocean waters as well as inland and near-coastal waters. Subaqueous dredged material capping is the controlled, accurate placement of contaminated dredged material at an appropriately selected open-water placement site, followed by a covering or cap of suitable isolating material. A number of capping operations under a variety of placement conditions have been accomplished. Conventional placement equipment and techniques are frequently used for a capping project, but these practices must be controlled more precisely than for conventional placement. Level bottom capping (LBC) is defined as the placement of a contaminated material in a mounded configuration and the subsequent covering of the mound with clean sediment. Contained aquatic disposal is similar to LBC but with the additional provision of some form of lateral confinement (e.g., placement in natural bottom depressions, constructed subaqueous pits, or behind subaqueous berms) to minimize spread of the materials on the bottom.