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

1. *
The issues that we observed and are
concerned about

2. *

3. *

4. *

5. *

7. *
Ratio = Watershed Area
Lake Area
Low High
Higher ratio – often poorer water quality

8. Drainage Areas and Lake Surface Areas for the Great Lakes
Drainage Area
Square miles
200,000 Lake Surface Area
150,000
100,000
50,000
0
Superior Michigan Huron Erie Ontario

9. 16
11
2
6 3

10. *
 Poor soils
 Naturally low in
“fertilizer”

12. *
Retention Time for each of the Great Lakes
Retention Time (years)
200
150
100
50
0
Superior Michigan Huron Erie Ontario

13. *
* Small drainage basin
*Less pollution coming in
* BUT very long retention time
*Pollutants accumulate and
remain for a long time

14. *

15. *

16. *

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20. *

21. * 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
*

22. *

23. Schmidt Creek

24. *

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34. *

36. * Temperature
* Precipitation
* Lake Levels
* Water temp and ice
cover
*

37. * 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
*

38. * 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%
*

39. *
Aids invasive species – both terrestrial
and land.
Shifts fish population to deeper water.
Creates thermal bar that can lead to
hypoxia in bays

41. *
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

44. *
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

48. *

49. *
More winds, more waves, altered
shorelines – means more erosion.

50. *
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.

51. *
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