Great Lakes: Areas of Concern

Areas of Concern (AOCs) are locations within the Great Lakes identified as having experienced high levels of environmental harm.

Under the Great Lakes Water Quality Agreement between Canada and the United States, 43 such areas were identified, 12 of which were Canadian and 5 of which were shared binationally. 

The 2012 Great Lakes Water Quality Agreement reaffirms both countries’ commitments to restoring water quality and ecosystem health in Great Lakes Areas of Concern.

The map shows the location of 43 Areas of Concerns around the Great Lakes basin: 12 are in Canada, 26 are in the United States, and 5 are shared by both countries. The map also shows the boundary of the Great Lakes basin.
Map of Canadian and U.S. Areas of Concern

The map shows the location of the 43 identified Areas of Concern around the Great Lakes basin - 12 are in Canada, 26 are in the United States, and 5 are shared by both countries. The international boundary between Canada and the United States runs through the middle of the lakes. The map also shows the boundary of the Great Lakes basin.

The Canadian Areas of Concern on Lake Superior are: Thunder Bay, Nipigon Bay, Jackfish Bay (in recovery) and Peninsula Harbour. St. Marys River is a binational Area of Concern shared by Canada and the United States. On Lake Huron, the Canadian Area of Concern is: Spanish Harbour (in recovery). Severn Sound and Collingwood Harbour are delisted. The St. Clair River and the Detroit River are binational Areas of Concern shared by Canada and the United States. On Lake Erie, Wheatley Harbour has been delisted. The Niagara River is a binational Area of Concern shared by Canada and the United States. On Lake Ontario, the Canadian Areas of Concern are: Hamilton Harbour, Toronto and Region, Port Hope Harbour and Bay of Quinte. The St. Lawrence River is a binational Area of Concern shared by Canada and the United States.

Areas of Concern in the United States on Lake Superior are: St. Louis River and Torch Lake. Deer Lake is delisted. Areas of Concern in the United States on Lake Michigan are: Manistique River, Fox River/Lower Green Bay, Sheboygan River, Milwaukee Estuary, Waukegan Harbor, Grand Calumet River, Kalamazoo River and Muskegon Lake. Lower Menominee River and White Lake are delisted. Areas of Concern in the United States on Lake Huron are: Saginaw River and Bay, and Clinton River. Areas of Concern in the United States on Lake Erie are: Rouge River, River Raisin, Maumee, Black River, Cuyahoga River and Buffalo River. Ashtabula River and Presque Isle Bay are delisted. Areas of Concern in the United States on Lake Ontario are: Eighteenmile Creek and Rochester Embayment. Oswego River is delisted.

Action is needed

Cleaning up AOCs contributes to the environmental, social and economic well-being of local communities and improves water quality and ecosystem health in the Great Lakes.

What we are doing

Since 1987, we have supported over 1,200 local action projects to clean up AOCs and restore their beneficial uses. A beneficial use is considered impaired if it has experienced negative changes to the chemical, physical or biological integrity of the water, interfering with its use or enjoyment. For each AOC, we collaborate with other federal departments, provincial and municipal governments, First Nations, Métis, watershed management agencies, other local public agencies and the public to develop and implement Remedial Action Plans. These plans identify an AOC’s impairments and causes; the criteria for the restoration of its beneficial uses; remedial actions to be taken, including those responsible for implementing these actions; and assess whether these actions have been effective.

To date, we have completely restored three AOCs: Severn Sound, Collingwood Harbour and Wheatley Harbour. In order for a site to be considered fully restored, all remedial actions must be complete and monitoring results show that water quality and ecosystem health criteria have been met.

Another two sites – Spanish Harbour and Jackfish Bay – are designated as Areas in Recovery, which means all required remedial actions are complete and the areas need more time for the environment to fully recover.

Contaminated sediment management projects have been completed in the Collingwood Harbour, Severn Sound,  Detroit River and Peninsula Harbour AOCs. Projects to remediate contaminated sediment are planned or are underway in the Thunder Bay, St. Clair River, Hamilton Harbour and Port Hope AOCs.

We provide financial and scientific support for restoration projects at the community level, which have enhanced water quality, restored fish and wildlife populations and habitats, improved management of municipal wastewater, and investigated and managed contaminated sediments in AOCs. These projects are helping to restore environmental health at the Areas of Concern and bringing them back from a legacy of environmental harm.

Read more about progress made to restore the Great Lakes Areas of Concern.

How you can get involved

There are many community and municipal groups engaged in cleaning up AOCs in their area. The success of many of the projects undertaken are in large part the result of enduring partnerships at binational, national, provincial and local levels. Without the dedicated effort and commitment of all of our partners, we could not have accomplished all that we have in these areas. If you are interested in being part of these efforts, please contact us at greatlakes-grandlacs@ec.gc.ca.

For detailed information on individual Canadian and binational AOCs, click on the appropriate link below:

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