FY18 St. Louis River AOC Slip 3 and Slip C Remedial Cap

The FY18 St. Louis River AOC Slip 3 and Slip C Remedial Cap project, managed by the Department of Defense under solicitation W911XK18B0007, involves the construction of remedial caps in two slips within the Duluth-Superior harbor to address sediment contamination. The scope of work requires the provision of all labor, materials, equipment, and management necessary to implement subaqueous caps over contaminated areas. In Slip 3, the project includes limited sediment leveling and the dredging of a 900 square foot area to facilitate material placement before capping approximately 0.88 acres. Slip C requires the capping of approximately 6 acres where contaminant concentrations exceed cleanup levels. Both remedial caps will be constructed using a two-layer system. Layer A will consist of dredged material sourced from the federal navigation channel, while Layer B will be a 6-inch layer of imported aggregate. This environmental remediation effort is overseen by the W072 Endist Detroit office to ensure that sediment concentrations are brought within acceptable safety levels.