Kerr T. (Tommy) Stevens: Attack on hog farms based on flawed research

Regarding the July 2 Point of View “How new tests prove hog, poultry pollution of NC waters”: The writers claim that new tests “prove” pollution by hog farms. They cited as evidence a recent study conducted for the U.S. Geological Survey by researcher Stephen L. Harden. But the study doesn’t support the authors’ allegations. In fact, an examination of the study data, conducted by a respected researcher at N.C. State University, concludes that: “The design and execution of the USGS stream sampling plan is seriously flawed.” Moreover, the data in the Harden report do not show that state water quality standards were exceeded in any of the watersheds sampled, including those with swine or poultry farms.

The examination of the data was conducted for the North Carolina Pork Council by Geo Solutions, Ltd. and overseen by its chief scientist, Dr. William Showers, a researcher at NCSU’s Marine, Earth and Atmospheric Sciences Department. The evaluation found that the Harden report’s conclusions were erroneous and unsupported because of limitations and deficiencies in the study design, including an inadequate number of stream samples per watershed; a lack of adequate stream sampling over a full one-year period covering all four climatic seasons; differing geology and soil types over the study area, and spatial limitations where background basin locations are distinctly different from the actual basins containing swine and poultry operations; a lack of poultry and swine population distribution across the sites; and a general miscategorization of several basins (based on historical use including basins dominated by industrial or municipal land uses).

Showers concluded that these deficiencies prevent the data from being used to draw any meaningful conclusions concerning potential influences of farms on coastal plain streams. Still, the Harden study is valuable, so long as it is not misused or misrepresented. Showers noted that the data collected can further our understanding of nutrient movement in watersheds. The data indicate that river buffers in watersheds, far more than the number of animals, are vital to protecting water quality. The importance of these buffers deserves further attention and examination.

I am a consultant to the Pork Council, so some critics of hog farms will dismiss what I say. Similarly, advocates for the farms may dismiss the POV because one of the writers is a staff attorney for the Waterkeeper Alliance, which is conducting an aggressive national campaign against all large animal-agriculture operations. But my experience is that the pork industry wants to get the facts – and act on the facts. That is why the Pork Council asked Showers to review the publicly available data.

The effect of agriculture on water quality is a vitally important issue, for our environment and for our economy. Our actions must be based on facts, not flawed science, inadequate data or politics. The facts in the Harden study don’t support the attacks on hog farms.

The length limit was waived to permit a fuller response to the Point of View.

This story was originally published July 8, 2015 at 5:17 PM with the headline "Kerr T. (Tommy) Stevens: Attack on hog farms based on flawed research."