Using Satellites to Monitor Water Quality

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Using Satellites to Monitor Water Quality

• Donald Kentner

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Problem

• Upper Great Lakes region has over 30,000 smaller
  lakes
• Minnesota has most of these lakes
• Was impossible to monitor every lake
• Only had the resources to monitor only a small
  percentage of the total lakes
• Most of the lakes were clean
• 50 to 100 lakes, less than one percent of the
  states lakes were monitored

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Problem cont.

• Those that were found to be unclean were in the
  southern part of Minnesota
• Researchers needed a faster method of identifying
  unclean lakes
• University of Minnesota decided to use Landsat
  satellites to map water clarity
• Landsat allowed for analysis at a fraction of the
  cost

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Research

• Clean lakes have clear water with very little
  algae growth
• Polluted lakes are murky, smelly, and overgrown
  with algae and exotic plants
• Lakes deteriorate due to runoff from farms, urban
  areas, industry, construction sites

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Clean vs. Dirty

• Clean with duckies Dirty with dead
  bodies

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Early Satellites

• Landsat series launched in 1970s had a resolution
  of 80 meters and four spectral bands
• Later versions of Landsat have carried improved
  sensors, increasing in power and accuracy
• Landsats 4 and 5 used an Enhanced Thematic
  Mapper, the most recent of the series is Landsat
  7, launched in 1999

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Modern Landsat

• Current versions are capable of seven different
  wavelengths of radiation and has a spatial
  resolution of 30 meters
• Is capable of retrieving data that is more
  accurate than samples taken from people on the
  ground
• 100 of the lakes greater than 20 acres were
  analyzed by Land sat images

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Lake Water Quality

• Clean Lake
• Dirty Lake

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Minnetonka in RGB
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Minnetonka in IR
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Differences
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• QUESTIONS?