Fishbeck was hired to conduct site investigation and remediation at the former Harbor Beach Power Plant, aiming for a site-wide No Further Action (NFA) determination without a post-closure agreement. The 95-acre site, located on a manmade peninsula along Lake Huron, was originally operated by DTE Energy and began operations in 1968 with a capacity of 125 MW. Demolition of power plant infrastructure took place from 2019 to 2021 to facilitate future redevelopment.
A site assessment found contaminants, mainly metals, exceeding generic groundwater surface water interface (GSI) criteria venting into Lake Huron. Fishbeck employed traditional evaluation methods alongside pore water sampling and mixing zone-based GSI criteria to assess exposure risk. Several source areas requiring remediation were identified, and excavation was chosen as the preferred remedial approach to achieve expedited closure.
The primary source area was the former coal ash pond, which covered 18.9 acres. Fishbeck supported the excavation of over 100,000 cubic yards of coal ash for off-site disposal, using visual observations, magnets, and soil analysis for guidance. The pond’s manmade embankments complicated excavation, especially with high water levels of Lake Huron in 2020 raising stability concerns, particularly for the north embankment where the clay liner didn’t reach the excavation floor. To mitigate risks of soil piping, Fishbeck’s team designed and implemented dewatering and secondary containment measures, successfully removing the coal ash without embankment failure.
After completing the coal ash pond, Fishbeck oversaw the excavation of sediment from four lagoons that supported the former on-site wastewater treatment plant. Following demolition of the power plant building, further investigation activities identified elevated concentrations of semi-volatile organic compounds in soil that presented a direct contact exposure risk. Fishbeck directed the removal of over 100,000 cubic yards of soil for off-site disposal at a licensed facility. In April 2024, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) approved a site-wide NFA without a post-closure agreement, thus achieving the client’s objectives for environmental closure.
