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Wisconsin's Great Lakes Areas of Concern (AOCs)

Map showing locations of Wisconsin's Great Lakes Areas of Concern

The Great Lakes and the rivers that feed them have been historically important centers of trade and industry in Wisconsin. As cities grew around these economic hubs, river and harbor sediments were polluted by chemicals. Important fish and wildlife habitat was lost. Today, the pollution and habitat loss cause problems for fish and wildlife and diminish our ability to fully use and enjoy the rivers and lakes.

The Great Lakes rivers and harbors that have been most severely affected by pollution and habitat loss are known as "Areas of Concern," or AOCs. These are geographically–defined sites that need special attention. They were designated in 1987 as part of an international agreement between the U.S. and Canada known as the Great Lakes Water Quality Agreement [exit DNR].

Wisconsin has five AOCs.


The goal of the AOC program is to clean up and restore these areas so that they are comparable to similar areas on the Great Lakes. The DNR's Office of Great Waters provides leadership for cleaning up these areas by:

  • providing a long–term vision and plan for the Great Lakes in Wisconsin;
  • ensuring that everyone who lives in and visits Wisconsin can use and enjoy our Great Lakes waters;
  • developing a common understanding of the steps, decisions and roles in the AOC program;
  • bringing citizens, nonprofit organizations, municipal leaders and agencies together to restore the Great Lakes; and
  • sharing the good news about the work that is being accomplished.

Read more Wisconsin's AOCs in Healing Our Rivers & Harbors [PDF], a special insert to the August 2013 issue of the Wisconsin Natural Resources magazine.

AOC 101 Video

Great Lakes rivers and harbors that have been most severely affected by pollution and habitat loss are called "Areas of Concern," or AOCs. Wisconsin has five of these geographically-defined sites that need special attention. Harbors and waterways are being cleaned up and restored around the nation with funding assistance from the Great Lakes Restoration Initiative. Learn how an AOC transforms and how to get involved locally.

Wisconsin DNR AOC Newsletter

The Wisconsin Lakesider is the DNR's AOC newsletter. Each edition includes some of the latest highlights of what's going on around the state at each of Wisconsin's five designated Great Lakes AOCs. The newsletter is currently on hiatus.