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Great Lakes AOCs

Oswego River AOC - Delisted

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Amy Pelka


The Oswego River/Harbor was designated an Area of Concern on the Great Lakes under the Great Lakes Water Quality Agreement of 1987. Oswego River/Harbor was delisted in 2006, after all the beneficial use impairments were restored that same year. Oswego was in fact the very first AOC located in the United States to be removed from the binational list of AOCs. The New York State Department of Environmental Conservation continues to monitor the AOC with support from the EPA.

The Oswego River/Harbor Area of Concern (AOC) is located on the southeastern shore of Lake Ontario and is centered in the city of Oswego, New York. The AOC includes the harbor area and the lower segment of the Oswego River up to the Varick power dam. The harbor itself is characterized as a multiple-use resource and over 1.2 million people live in the drainage basin. The Oswego River watershed includes the Finger Lakes, industries, municipalities, and extensive areas of farmland and forest, totaling an area of over 5,100 square miles.

Prior to delisting, the Oswego River/Harbor AOC was degraded due to hazardous waste sites, municipal sewage discharges, combined sewer overflows, and runoff from streets and agriculture. Due to the above pollution sources, contaminants found within the AOC included polychlorinated biphenyls, dioxins, cyanide, grease, oil, mirex, and excessive levels of phosphorus. Another concern in the AOC was fish spawning habitat reduction due to water flow restriction at the Varick power dam.

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Beneficial Use Impairments


Following the success of remediation and restoration work, the four beneficial use impairments, or BUIs, in the Oswego River/Harbor AOC were restored. These BUIs are listed below. Beneficial use impairments are designations given by the International Joint Commission representing different types of significant environmental degradation. As cleanup work is completed and monitoring demonstrates sufficient environmental health improvements, BUIs can be removed. Once all BUIs are removed, the process of delisting the AOC can begin.

  • Restrictions on Fish and Wildlife Consumption - Removed 2006
  • Degraded Fish and Wildlife Populations - Removed 2006
  • Loss of Fish and Wildlife Habitat - Removed 2006
  • Eutrophication or Undesirable Algae - Removed 2006

Oswego River was delisted in 2006.

More information:

General information about BUIs: Beneficial Use Impairments for the Great Lakes AOCs

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Remediation and Restoration Work

EPA has continually worked with federal, state, and local partners to address the impairments within the AOC. Since the designation of the AOC, the United States Federal Energy Regulatory Commission’s Oswego River power dam license was established and committed to providing enhanced run-of-river flow throughout the year. Other efforts in the AOC included corrective actions by the city of Oswego to address combined sewer overflows, practices to reduce municipal and industrial point and nonpoint sources of pollutants, fish surveys, water quality monitoring, sediment surveys, and assessment of other potential impairments.

Oswego AOC was officially delisted in 2006, after review of impairments within the AOC demonstrated improvement to levels similar to other areas in Lake Ontario. The remaining fish consumption advisory in the area is due to activities outside of the AOC and is similar to other areas in Lake Ontario. Impairments resulting from activities outside of the AOC are monitored and addressed through the Lake Ontario Lakewide Action and Management Plans.

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The following links exit the site Exi

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