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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.

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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

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Environmental Issues

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

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What is EPA Doing? 

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