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  2. The Great Lakes

Lake Ontario

Map of Lake Ontario

Lake Ontario is the last of the chain of Great Lakes that straddle the Canada/United States border. Since Lake Ontario is the downstream Great Lake, it is impacted by human activities occurring throughout the Lake Superior, Michigan, Huron, and Erie basins.

On This Page:
  • About Lake Ontario
  • Enivironmental Issues
  • What is EPA Doing?

About Lake Ontario

  • second smallest by volume
  • average depth 283 ft. (86m)
  • retention time = 6 years (a measure based on the volume of water in the lake and the mean rate of outflow)
  • urban industrial centers (Hamilton and Toronto) on the Canadian side
  • U.S. shore is less urbanized, not intensively farmed

NOAA Image Measurement of Depth of Water in Lake Ontario

Environmental Issues

There are several major issues affecting the health of Lake Ontario:

The following links exit the site

  • Degradation of the lower food chain
  • Loss of biodiversity
  • Fish consumption restrictions
  • Aquatic invasive species
  • Nearshore water quality

What is EPA Doing? 

  • Lake Ontario LAMPS and Associated Reports
  • Lake Ontario Great Lakes Areas of Concern (AOCs)
    • Eighteenmile Creek AOC - New York
    • Niagara River AOC - New York
    • Oswego River AOC - New York DELISTED
    • Rochester Embayment AOC - New York
    • St. Lawrence River AOC - New York and St. Lawrence River AOC - Canada 
    • Hamilton Harbour AOC - Canada 
    • Toronto and Region AOC - Canada 
    • Port Hope Harbour AOC - Canada 
    • Bay of Quinte AOC - Canada 
  • Great Lakes Restoration Initiative Grants
    • Paul Smith's College of Arts and Sciences ($499,816) for invasive species prevention

  • Lake Ontario Tributaries: 2009-2010 Field Data Report March 2011
  • Niagara River Toxics Management Plan Annual Status Reports
  • Niagara River Toxics Management Plan Progress Reports and Work Plans

The Great Lakes

  • The Great Lakes
    • Great Lakes Facts and Figures
    • Physical Features
  • Contaminated Sediment
  • Invasive Species
  • Water Quality
  • Related Information
Contact Us about the Great Lakes
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on April 8, 2025
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