Satellite Imagery Shows How Much of South Dakota’s Flooded Fields Were Unable to be Farmed

Caitlin Dempsey


Intense winter storms and abnormally high spring rainfall in 2019 combined with snow and ice melt caused widespread flooding across parts of Nebraska, Iowa, South Dakota, and Wisconsin.  Flooded fields means that certain crops were unable to be planted.  Farmer report these as “prevented planting” acres to insurance companies. Prevented planting acreage, a crop insurance term, are fields that were unable to be planted due to natural disasters such as floods or drought conditions.

In August of 2019, the U.S. Department of Agriculture reported that South Dakota had 3.9 million “prevented planting” acres.  South Dakota reported the largest amount of acreage than any other state.  Using Landsat’s near-infrared and red bands, researchers can identify areas in satellite imagery of South Dakota that were unplanted.  Using Normalized Difference Vegetation Index (NDVI), researchers can calculate the amount of growing vegetation.

The two Landsat satellite images below show field conditions in southeastern South Dakotafor last summer (August 11, 2018) and this summer (July 29, 2018).  The banks of the James River are still swollen with water in the 2019 image.  Vegetated areas are shades of green and unplanted fields show as bright magenta.  Use the slider handle to compare the two satellite images.  Notice how much more magenta, which are unplanted fields, is shown on the 2019 image versus the 2018 image.

Compare Satellite Images of Southeastern South Dakota: 2018 – 2019

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Source: South Dakota’s Unplanted Acres of 2019, USGS

Video: Satellite Imagery of Flooding in Nebraska

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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.