Fact Sheet: Perimeter Wall Replacement
Originally published February 2025.
Construction to take two years, starting in early 2025
EPA and the U.S. Army Corps of Engineers will be replacing the existing sheet pile wall along the perimeter of the Wyckoff/Eagle Harbor Site. Portions of the existing wall are deteriorating due to decades of exposure to natural elements.
Construction will begin in early 2025 to prepare the site for the replacement wall that will be made of reinforced concrete. Most of the construction will be on the inland side of the existing wall and will not be visible until the existing sheet pile wall is removed.
Work will include the following elements:
- Debris excavation to remove old bulkheads.
- Treatment of contaminated soil with in-situ solidification/stabilization, or ISS (see below for more information about ISS).
- Installation of a high-strength concrete wall reinforced with steel.
- Construction of an exterior marine-grade concrete armor wall to protect from weathering.
- Cutting and removing the existing sheet pile wall, once the new wall is complete.
How it will impact the community
EPA, the Army Corps of Engineers and their contractors will take steps to lessen the impacts as much as possible during construction.
Beach access: For public safety, portions of the beaches will be closed during certain stages of construction. Barricades will be placed to prevent access to construction zones.
Noise: Heavy equipment will be used during construction, and construction will be generally consistent with the City of Bainbridge Island noise regulations. Contractors will take steps to reduce overall noise and EPA will perform daily perimeter noise monitoring.
Roadways: An increased number of construction vehicles, including large trucks, will be on local roads throughout the day. For public safety, Creosote Place NE roadway and parking lot will be closed beginning in March 2025.
Odors: Some construction activities may cause odors and EPA will perform daily perimeter air quality monitoring.
About in-situ solidification/stabilization
During construction, a cleanup method called in-situ solidification/stabilization, or ISS, will be used to limit the spread of contamination in soil and groundwater by stabilizing and solidifying the contaminated soil.
ISS solidifies by physically mixing cement with the soil (forming a monolith) and stabilizes by binding the contaminants to soil. ISS reduces how fast groundwater can move through the solidified contaminated soil which slows the rate of leaching and limits the groundwater exposure to contaminated soil.
This basic chemical treatment with cement limits the ability of the creosote to migrate into the groundwater and marine environment.
A printable version of this fact sheet is also available: Perimeter Wall Replacement at Wyckoff/Eagle Harbor Superfund Site (pdf) - February 2025