Source: NASA Video @ YouTube
“The Landsat satellites have also proved to be very useful, particularly for trying to do more detailed, finer-scale risk mapping.”
—Dr. Michael Wimberly, Landscape Ecologist, South Dakota State University on using satellite imagery to fight West Nile Virus by creating weekly risk assessment maps

Above the Earth, Below the Surface: Landsat’s Role in Monitoring Water Quality
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.