Lower Fox River Contaminated Sediment Cleanup

Background

The Lower Fox River (LFR) flows nearly 40 miles from the Lake Winnebago outlet to Green Bay in Lake Michigan. River sediment was contaminated by polychlorinated biphenyls (PCBs) from historic industrial activities along the river. The LFR Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) site was separated into operable units to manage the remedy, beginning at the outlet of Lake Winnebago, proceeding down river through the Lower Fox River (OUs 1, 2, 3, and 4) and ending at Green Bay (Lake Michigan) (OU 5). It is arguably the largest PCB cleanup project in the country.

Stakeholders include a complex assemblage of responsible parties, government agencies, multiple cities and municipalities, hundreds of riparian owners and thousands of frequent users of the river and Lake Michigan. Foth was retained by P.H. Glatfelter Co. (later as part of GW Partners) in 2002 to perform pre-design investigation work, agency negotiations, remedial design (RD) and construction oversight for remedial action (RA) in OU1. Active remediation concluded in 2009 and a certification of completion was issued by USEPA in 2010. Foth was also retained by the Lower Fox River Remediation, LLC in 2008 as the owner’s on-site representative to provide engineering and scientific assistance and oversight of the prime contractor and its sub-contractors on this multi-year sediment cleanup project encompassing OUs 2-5. Active remediation in OUs 2-5 was completed in 2020 and a certification of completion was issued by USEPA in 2022.

Approach

From very early on, Foth was involved in multiple facets of the work associated with this superfund mega-site. Starting in the early 1990s and prior to the commencement of RD in OU1, Foth designed and oversaw the initial remedial construction pilot studies in multiple OUs to evaluate the efficacy of dredging and capping solutions. Foth has served as the design engineer and RA certifying engineer or provided construction oversight for the placement of engineered caps and sand covers over 275 acres of river bottom. Foth provided construction support including construction quality assurance during the remedial action for several OUs, and later served as owner’s representative for OUs 2-5 providing detailed site documentation and RD/RA quality review. To evaluate long-term remedy effectiveness, the Foth team is currently executing the 30-year long-term monitoring program for the LFR mega-site.

A key highlight of our work was the Lower Fox River RD for OU1 which included integration of highly complex design elements and the optimization of alternative remedial approaches. This work utilized innovative statistical modeling to evaluate numerous project designs, ultimately selecting an optimized design that met all clean-up objectives, while reducing project cost by tens of millions of dollars.

Results

Having a deep understanding of both the CERCLA/Superfund process and sediment remedial design has allowed Foth to strategically develop innovative approaches to advance client objectives at this superfund site. With the removal of approximately 6.5 million cubic yards of contaminated sediment and the installation of nearly 1,000 acres of engineered caps and sand covers, the Lower Fox River is being restored as a vital natural resource to local communities, the State of Wisconsin, and fishermen from across the U.S.