Detroit River – RiverWalk Shoreline Stabilization

Detroit, Michigan – Great Lakes

The Detroit Riverfront Conservancy (DRFC) has established a RiverWalk along much of the Detroit River shoreline as part of the downtown revitalization in the City of Detroit. At the planned easternmost section of the RiverWalk, located near the MacArthur Bridge connecting the City of Detroit to Belle Isle, heavy industrial use dating back over a century resulted in contamination with polycyclic aromatic hydrocarbons (PAHs) and other constituents of concern in the sediment adjacent to an aging bulkhead wall. To allow installation of the final stretch of the RiverWalk at this location, the bulkhead wall required additional support in the form of a riprap revetment. However, before the revetment could be installed, a multilayer engineered cap was required to address the legacy sediment contamination.

On behalf of DRFC, Anchor QEA designed the engineered cap consisting of a chemical isolation layer, a geotechnical filter layer, and an armor layer. DRFC entered into an agreement with the U.S. Environmental Protection Agency (USEPA) under the Great Lakes Legacy Act as a non-federal sponsor to facilitate the construction of the engineered cap. USEPA’s contractor installed the engineered cap. During construction, Anchor QEA provided on-site construction quality assurance (CQA) services to verify that the engineered cap was completed in accordance with the design. CQA services included the following:

• Reviewing contractor submittals and work plans
• Verifying the suitability of cap materials for use
• Surveying and taking physical measurements to certify that the cap was constructed to the required minimum thickness
• Sampling to confirm that the chemical isolation layer contained the required amount of activated carbon
• Monitoring porewater pressure in the underlying sediment during engineered cap installation
• Responding to contractor requests for information
• Documenting the construction in a Remedial Action Report

The engineered cap was successfully installed, allowing construction of the RiverWalk to begin along this portion of the Detroit River shoreline. Additional construction is occurring at the property throughout 2021 and 2022, including revetment installation and RiverWalk construction. The project is currently on schedule to open to traffic in November 2022.