Analysis of strategies for seabed remediation at log handling facilities in British Columbia

The purpose of this document was to explore and evaluate alternative technologies to remediate marine sediments polluted with bark and woody debris deposits at water-based log handling facilities (LHFs) on the B.C. coast. Log handling activities, such as dumping and booming, are incompatible with the maintenance of existing productive estuarine and marine habitats. The study involved a review and evaluation of the literature of management strategies for contaminated sediments, followed by an analysis and evaluation for their applicability to submerged wood waste. Context for the evaluation was confirmed by a SCUBA dive and site documentation of one site. There are currently Best Management Practices developed for the decommissioning and rehabilitation of LHFs in B.C.; however, no specific strategies have been recommended that are technically feasible, effective for the recovery of benthic communities, and cost-effective. The alternatives assessed and compared in this study were mechanical dredging, hydraulic dredging, in-situ capping, no-action, monitored natural recovery, in-situ biological treatment and in-situ chemical treatment. Factors beyond the actual remedial work at an LHF, such as disposal technologies and beneficial use, were also considered. Research findings provided the basis for recommendations regarding seabed remediation and benthic recovery at polluted log handling sites. The recommendations include specific LHF site types that would most benefit from the particular remedial approach. Equipment, project design and disposal suggestions are offered.;Optimal remediation for many sites involves capping LHFs using clean dredged material from navigational dredging activities. This approach solves both the significant problem of shipping lane material disposal and LHF capping needs to provide suitable habitat for recolonization by desirable benthic species---a problem in one area is used as a solution in another area.;Key words. Remediation; log handling facility; marine sediment reclamation; bark; wood; dredging; in-situ capping; monitored natural recovery; marine recolonization; benthic succession.