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Great Lakes AOCs

About the St. Louis River and Bay AOC

map showing the state approved boundary of the St. Louis River & Bay AOCSt. Louis River and Bay AOC Boundary MapThe St. Louis River became an Area of Concern on the Great Lakes under the Great Lakes Water Quality Agreement of 1987.

AOC Boundaries

The St. Louis River drains 3,634 square miles and enters the southwest corner of Lake Superior between Duluth, Minnesota, and Superior, Wisconsin. 
The Area of Concern includes:
  • The Interlake and U.S. Steel Superfund sites
  • Newton Creek
  • Hog Island Inlet

Sources of Pollution

The area was considered highly degraded because of:
  • historical discharges
  • Superfund sites
  • high levels of contamination in river sediments
  • the bay receiving wastewater discharge from the local sanitation facility
  • landfill sites and other point-source dischargers have also contributed to the contamination

Beneficial Use Impairments

Beneficial Use Impairments for the Great Lakes AOCs

  • Restrictions on fish and wildlife consumption
  • Excessive loading of sediment and nutrients
  • Degradation of fish and wildlife populations
  • Beach closings
  • Fish tumors or other deformities
  • Degradation of aesthetics - REMOVED 2014
  • Degradation of benthos
  • Loss of fish and wildlife habitat
  • Delisting targets

In 1987, the St. Louis River and Bay was declared an Area of Concern and in 1992 a Remedial Action Plan Stage I document was completed.


Restoring the St. Louis River AOC (timeline)

Hog Island Legacy Act Restoration

Spirit Lake Legacy Act Cleanup


The Corps offers planning & technical assistance and contract management to the Minnesota Pollution Control Agency (MPCA) to assist in their effort to delist their beneficial use impairments in the St. Louis River and Bay AOC.

The U.S. Fish and Wildlife Service’s Environmental Contaminants program at the Twin Cities Ecological Services Field Office has been an active partner within the lower the St. Louis River conservation community for more than 13 years, assisting with fixing contaminated sediments, investigation of chemical effects, as well as a variety of other fish and wildlife habitat projects.

The following links exit the site Exit

In 2005, a survey of the St. Louis River was completed through a collaborative effort between Fond du Lac’s Resource Management Division, the 1854 Treaty Authority, and Minnesota DNR Fisheries.

In response to citizen demands to clean up the St. Louis River, the Minnesota Legislature created the Western Lake Superior Sanitary District in 1971 to improve and protect the waters of the St. Louis River and its tributaries. In 1974, additional legislation was passed, giving WLSSD the added responsibility of solid waste management.

River Quest, a  2.5-hour boat trip, teaches students about the St. Louis River ecosystem and related commercial, industrial and recreational activities. They are introduced to a variety of topics:
  • pollution prevention,
  • stopping aquatic invaders,
  • boating safety,
  • commercial shipping.

Wisconsin DNR: St. Louis River Area of  Concern