Superior Sediment Remediation Projects

Superior Slips

The Superior Slips Sediment Remediation Project is one of several projects to clean up and restore the St. Louis River Area of Concern. This project focuses on contaminated sediment in three industrial shipping slips at the Port of Superior: General Mills Slip, Oil Barge Dock Slip and Tower Avenue Slip.

Over a century of heavy industrial activities next to the St. Louis River have led to environmental degradation of sediment in areas of the harbor. Sediment in these slips is contaminated with metals, mercury, organotin, polycyclic aromatic hydrocarbons, and other compounds that are targeted for cleanup by 2026 as part of the overall effort to remove the St. Louis River from the list of most polluted sites on the Great Lakes.

The activity status for this project includes:

• Investigating and characterizing the nature and extent of sediment contamination - completed in 2023.
• Developing and evaluating alternatives for remediating sediment contamination - completed in 2023.
• Developing a recommended alternative to address the contamination - Spring 2024

Project Schedule and Opportunities to Get Involved

The Superior Slips Sediment Remediation Feasibility Study began in June 2022 and is projected to be completed in spring 2024 with a set of recommendations for actions to clean up sediment in the slips.

Based on its consultant’s evaluation, the DNR is recommending options for removing contaminated sediment in three large slips in the Port of Superior. More details are available in the remedial action options report (RAOR) for each slip in the Technical Reports section below.

The DNR plans to seek additional project partners and perform limited pre-design activities before starting remedial design. The design of the chosen remedy is anticipated to occur in 2024 - 2025, and the work to clean up the polluted sediment is expected to take place in 2026 and beyond.

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Public Information Meeting Materials

• View Zoom recording of the public meeting [VIDEO Length 49:47]
Public Meeting Presentation on Superior Slips Remediation Options

Technical Reports

The following reports provide details about sediment contamination evaluations and other project findings.

• Overview: Superior Slips Dredge Project - NEW!
• Poster: Cleaning Up Contaminated Sediment in the Superior Slips - NEW!
• Poster: Feasibility Studies & Preliminary Designs for Contaminated Sediment Remediation in the Superior Slips

Links to Remedial Action Options Reports

Additional technical reports are also available from the DNR Bureau of Remediation & Redevelopment Tracking System (BRRTS) on the Web (BOTW) at https://dnr.wisconsin.gov/topic/Brownfields/botw.html. These reports can be obtained from BOTW by searching for the BRRTS activity number 11-16-591466 or Activity or Location Name = Superior Slips.  

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