As the end of the year approaches, we wanted to provide an update on the work that has continued throughout the fall to construct 27 acres of engineered caps at our House Street site in accordance with an EGLE-approved Work Plan.
Major areas of focus over the past few months include placement of topsoil over the mounds, seeding the topsoil, installation of erosion controls, and continued construction of the retention basin. Weather events interfered with performance of some work this fall, but the project remains on schedule and additional details and photos showing each element of the work are included below.
Restoration and seeding on the Northwest, Northeast, and Southeast mounds is complete and the Southwest Mound is stabilized for the winter using topsoil, erosion control blanket, and temporary seeding. Final topsoil grading, seeding, storm water work (drainage swale and retention basin) as well as the final grading and permanent seeding outside of the mounds will be completed in Spring 2025. In addition, each of the geomembrane liners have been covered by at least 2 feet of soil, referred to as Barrier Protection Material (BPM).
The BPM layer is overlain by a minimum of 6 inches of imported topsoil. In October, RECON completed placing topsoil on the Northwest, Northeast, and Southeast mounds. They have placed topsoil in the northern portion of the Southwest Mound and expect to complete topsoil import to cover the remainder of the Southwest Mound in the spring. The southern portion of the Southwest Mound will be covered with erosion control blankets and temporary seed to stabilize the underlying soil for the winter.
In late October, RECON completed hydroseeding on the Northwest and Northeast Mounds, and the Southeast mound was seeded in early November. Hydroseeding is a process which involves spraying a mixture of seeds, fertilizer, soil amendments, mulch, and water onto the soil. Temporary winter seeding was applied over the southern portion of the southwest mound and the areas outside of the Mounds on December 2 and December 10. Other soil erosion controls will be installed as necessary to protect the site over the winter, with final topsoil import, grading and seed cover for the Southwest Mound and areas outside of the mounds expected to be complete in Spring 2025.
RECON has made progress in converting the Temporary Retention Basin into the Permanent Retention Basin, including widening and deepening the excavation and adding rip-rap stone to the bottom of the basin. Construction of the Permanent Retention Basin, drainage swale, and access road will continue in the Spring of 2025 and we expect that work to be complete in early Summer 2025.
RECON finished earthwork on December 7 and equipment demobilization concluded on December 13. Perimeter air monitoring ended on December 7, and there have been no exceedances of action levels. The air monitoring data is available in the “Documents” section of this blog or by clicking on this link. We continue to evaluate the data to be proactive with dust control as needed.
We will continue to use this blog to keep the community informed as our remediation work continues in the weeks and months ahead. As always, residents with questions or feedback are encouraged to contact Wolverine Worldwide directly at HouseStreet@wwwinc.com or (616) 866-5627.