Collingwood Harbour: Area of Concern (Delisted)

Collingwood Harbour was designated an Area of Concern (AOC) in 1987 under the Canada-U.S. Great Lakes Water Quality Agreement. A history of industrialization, urbanization and agricultural land use activities along its shores and tributaries contributed to the degraded environmental quality. Nine out of 14 beneficial use impairments (BUIs) were identified, which measure the environmental, human health or economic impact of poor water quality. An additional beneficial use was deemed “requiring further assessment”, meaning more information was required to determine whether it was impaired. 


In 1994, Collingwood Harbour became the first Canadian AOC to be delisted. We delist an AOC when monitoring shows that targets for all BUIs have been met and environmental quality has been restored.

Monitoring confirmed that environmental quality was restored through:  

  • improvements to the Collingwood municipal sewage treatment plant, which reduced phosphorus loads by 63% (from 5333 kg/year to 1923 kg/year) and resulted in the reduction of nuisance algae in the harbour
  • the cleanup of 7,300 cubic metres of sediments contaminated with heavy metals (copper, lead, zinc and chromium)
  • changes to local policies to protect the 96-hectare Collingwood Wetland Complex
  • the creation of over 5 kilometres of stream and shoreline habitat, rehabilitation of 20 hectares of wetlands, and addition of fish spawning beds mostly along Black Ash Creek, which led to an increase in prey fish and return of species such as yellow pickerel and northern pike after an absence of over 30 years

Restoration of beneficial uses

All beneficial uses are no longer considered “impaired”. These included:

  • restrictions on fish and wildlife consumption (1994)
  • degradation of fish and wildlife populations (1994)
  • bird or animal deformities or reproduction problems (1994)
  • degradation of benthos (1994)
  • restrictions on dredging activities (1994)
  • eutrophication or undesirable algae (1994)
  • beach closings (1994)
  • degradation of aesthetics (1994)
  • degradation of phytoplankton and zooplankton populations (1994)
  • loss of fish and wildlife habitat (1994)

Our partners

On the Canadian side, we partner with other levels of government, non-government groups, Indigenous communities and members of the public. This restoration work required a large amount of scientific and technical expertise, local knowledge, hard work and the help of:

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