Michigan
The Michigan Dredging Project site has been active since 1985 when EPA completed the original site assessment. Extensive sediment and upland remediation and restoration has progressed since 1998. The project has six operable units (OUs). This contract addresses OU5, Area 1, and the Crown Vantage Side – an 80-mile stretch. Area 1 is the most upstream segment of the site, flowing through the communities of Michigan. OU5 is divided into seven areas, which are separated by dams or former dams. The ROD established a final remedial goal of 0.33 mg/kg for PCBs in sediment to be achieved over time in each of the sections in Area 1.
As the prime contractor, Sevenson dredged 62,266 CY of non-TSCA and 14,578 CY of TSCA material. Sevenson installed 1,850 LF of AZ-19-700 and AZ-26-700 sheet piles, ranging from 20–40 ft. deep; stabilized the material with Type II Portland cement, stabilizing 123,319 tons of TSCA and non-TSCA material, where it was transported material off-site to Subtitle C and D disposal facilities, respectively; capped over a 361,000 sq. ft. area; and designed, constructed, operated, and maintained a 100-GPM WWTP, which treated and discharged >1.5M gallons of water via the NPDES permit.