Satellite imagery gives researchers timeline of when swine waste lagoons
were built

Date:
February 14, 2022
Source:
North Carolina State University
Summary:
Researchers have developed an automated technique that uses
satellite imagery to determine when swine waste lagoons were
constructed, allowing researchers to determine the extent to which
these facilities may have affected environmental quality.



FULL STORY ========================================================================== Researchers at North Carolina State University have developed an automated technique that uses satellite imagery to determine when swine waste
lagoons were constructed, allowing researchers to determine the extent
to which these facilities may have affected environmental quality.


========================================================================== Swine waste lagoons are outdoor basins used to store liquid manure
produced by swine farming operations.

"Historically, we only knew how many pigs were found on farms as an
aggregate for each county, and that data was only reported to USDA every
five years," says Lise Montefiore, lead author of a paper on the work and
a postdoctoral researcher at NC State. "Within the past 20 to 30 years, permitting requirements were established that allow us to determine
where swine farms and waste lagoons are located.

"However, we didn't know when these lagoons were built, making it
difficult for us to understand the impact the lagoons had on water
quality, air quality and so on. Our work here gives us specific data on
when each lagoon was constructed. By comparing this information with
historical environmental monitoring data, we can get a much better understanding of how the lagoons have affected the environment."
"While we focused on North Carolina, this technique could be used to
establish lagoon construction dates for any area where we have location
data for swine waste lagoons and historical satellite images," says
Natalie Nelson, corresponding author of the paper and an assistant
professor of biological and agricultural engineering at NC State.

The researchers started the project with location data on 3,405 swine
waste lagoons.

The researchers then collected publicly available satellite images,
taken between 1984 and 2012, of the areas where the waste lagoons are
located. To determine when each lagoon was constructed, the researchers automated a piece of software to assess the extent to which light
reflected off the lagoon's location. Because lagoons are watery, they
reflect light differently than dry land. So, when the reflectance at a
site switched from "dry" to "wet," they knew that a lagoon had been built.

"We found that approximately 16% of the lagoons were already in place
before 1987, so there is no exact construction date for those facilities," Montefiore says. "However, we were able to establish the construction
date for the remaining lagoons with a margin of error of about one year."
"At this point, our goal is to share this data with the broader research community so that we can begin to understand how the construction of
these facilities may correlate to changes in air quality, water quality
or other environmental variables." "This is also the first time that
we've had this level of historical and geographic detail in terms of understanding how animal agriculture has expanded in North Carolina,"
Nelson says. "That can help us understand changes to the landscape and
changes to land use over the past 40 years." The work was done with
support from North Carolina Sea Grant under award number NA18OAR4170069;
the Water Resources Research Institute; the Gulf Research Program of
the National Academies of Sciences, Engineering, and Medicine; the USDA National Institute of Food and Agriculture, under grant 2019-67032-29074
and Hatch Projects 1016068 and 1022103; and a U.S. Geological Survey
Southeast Climate Adaptation Science Center graduate fellowship awarded
to Montefiore.

========================================================================== Story Source: Materials provided by
North_Carolina_State_University. Original written by Matt Shipman. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Swine_waste_lagoon ========================================================================== Journal Reference:
1. Lise R. Montefiore, Natalie G. Nelson, Amanda Dean, Mahmoud Sharara.

Reconstructing the historical expansion of industrial swine
production from Landsat imagery. Scientific Reports, 2022; 12 (1)
DOI: 10.1038/ s41598-022-05789-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214111801.htm

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