Areas of Concern

What is an Area of Concern?

An Area of Concern (AOC) is a location where environmental quality is degraded compared to other areas in the Great Lake Basin resulting in the impairment of beneficial uses. A total of 43 AOCs were identified (see the map below) as a result of Annex 2 of the Great Lakes Water Quality Agreement (GLWQA).


Detroit River Area of ConcernDetroit River AOC (COLOUR) - Feb 2009 cropped

The Detroit River is a 51 km-long connecting channel   that links Lake St. Clair to the western basin of Lake Erie. Its width varies considerably from 600 m at the Ambassador Bridge to over 6 km where it empties into Lake Erie. Water depths range from an average of 9-15 m in the upper river to 3-9 m in the lower river). The Detroit River Canadian AOC refers to the Canadian portion of the Detroit River proper.

Issues facing the Detroit River are combined sewer overflows, urbanization and land use (degradation of habitat), and toxic contaminants (e.g., mercury, PCBs, PAHs, and metals) in water and sediment. These environmental issues have been identified as being related to, or the cause of, the impairment of several beneficial uses.

For more information on the remediation actions occurring on the US side of the Detroit River, please visit:


Get Involved!

From tree plantings and clean ups, to advocacy and education programs, CLICK HERE to find out how you can be involved with protecting and enhancing the Detroit River.