Lake superior areas of concern

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Presentation on Lake Superior issues based on observations of our Full Circle Superior walk around the lake.

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  • This is one of the special presentations that Kate and I do for classes or keynotes in addition to our story of the hike around Lake Superior in 2010
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Lake superior areas of concern

  1. 1. *The issues that we observed and areconcerned about
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  6. 6. * Ratio = Watershed Area Lake AreaLow High Higher ratio – often poorer water quality
  7. 7. Drainage Areas and Lake Surface Areas for the Great Lakes Drainage AreaSquare miles 200,000 Lake Surface Area 150,000 100,000 50,000 0 Superior Michigan Huron Erie Ontario
  8. 8. 16 11 2 6 3
  9. 9. * Poor soils Naturally low in “fertilizer”
  10. 10. * Retention Time for each of the Great LakesRetention Time (years) 200 150 100 50 0 Superior Michigan Huron Erie Ontario
  11. 11. ** Small drainage basin *Less pollution coming in* BUT very long retention time *Pollutants accumulate and remain for a long time
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  19. 19. * BWCAW* North of Marquette* Ontario* When mining activities expose sulfide bearing rock to air and water it decomposes releasing among other chemicals, sulfuric acid which causes acid mine drainage and heavy metal acid rain* Sulfide mining kills rivers, lakes, streams and ponds *
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  21. 21. Schmidt Creek
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  33. 33. * Temperature * Precipitation * Lake Levels * Water temp and ice cover*
  34. 34. * 1970 – 2000 annual * 10% increase in temp rises .4F per precipitation across decade region since 1900* Last two decades * Frequency of heavy hottest months in rains – doubled. Great Lakes region * Strong cyclones in Nov* By 2003 last spring – Dec doubled freeze one week early * Since 1951 increase in lake effect snow *
  35. 35. * Lake Levels had thee * Near shore decades of high water temperatures rise until 1990’s. * Summer surface water* Since 1997 there has temp increased 4.5 F since 1980. been a severe decrease in water level * Maximum ice formation decrease* Since 1997Huron and 10% Michigan have dropped * Surface wind increase 3.5 feet. 5% *
  36. 36. * Aids invasive species – both terrestrial and land. Shifts fish population to deeper water. Creates thermal bar that can lead to hypoxia in bays
  37. 37. * Over all precipitation up. Individual severe storms increase dramatically. Between severe event – drought and drying. Winter storms break up ice cover. Lake effect snow changing to lake effect winter rain
  38. 38. * Reduced ice pack creates more evaporation Overall lake level will lower Lower lakes will lower more than Superior and put pressure on Superior to fill their basins Lower lake levels also impact the ground water reservoir
  39. 39. *
  40. 40. * More winds, more waves, altered shorelines – means more erosion.
  41. 41. * Shipping depends upon hauling large volumes of materials in and out of ports. Ports maintain minimum clearance for ships. Cost of dredging, reshaping harbors is large.
  42. 42. * Long summer stratification will increase oxygen depletion – especially in lower great lakes and Lake Superior bays. Increase in invasive species Invasive species will be favored over native fish Wetlands will be damaged and dried

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