Evidence from America’s most intensive hog producing region indicate
that large hog operations do not hurt water quality
Data collected by the North Carolina Department of Environment and Natural Resources indicate that the water quality in the Black river, the drainage basin for North Carolina’s most intensive hog producing region, has remained excellent, despite a 500 percent increase in the area’s hog population. In fact, the water quality of the rivers and streams in this region may even have improved slightly. (For a version of this paper that includes a graph of nitrate levels in the Black River, get the formatted .pdf version of this press release by clicking on the “Articles and Papers” button to the left and going to the “Key Publications” section. Or go to http://www.cgfi.org/pubs2.cfm)
Because of the large concentration of hog farms in the Black river basin, as well as its largely rural character, the Black river represents a unique opportunity to gauge the specific effects of hog farms on water quality. In contrast, other watersheds are impacted by the nutrient pollution from cities, towns, and industries which make it difficult to determine the effects of farm practices. (Sewage treatment only removes a portion of the nutrients from wastewater.)
The amount of hog manure applied to crop fields within the Black river watershed has increased dramatically over the last 15 years as the hog population increased by five hundred percent. This has lead to fears that nutrients from hog manure would runoff crop fields and pollute waterways. But these fears appear to be unfounded.
The data are clear – nutrient concentrations in the Black river have remained low and essentially unchanged. While it may be reasonably argued that the relatively small amount of water quality data (quarterly measurements for 1974, and 1981-86; monthly monitoring from 1992-98) preclude any precise conclusions, it is clear that the water quality of the Black has remained excellent over this time period. The Black River is considered an “outstanding resource water†by the North Carolina Department of Environment and Natural Resources. The Black River also has a fish habitat rating of “excellent.â€
This indicates that the practice of spreading hog manure on crop fields is fully compatible with good water quality. This should come as no surprise, since confinement hog farms collect and use their hog manure as organic fertilizer on crop fields. This is clearly better for water quality than the traditional method of raising hogs outdoors, where the hog wastes may be washed directly into waterways.
Considering the contentious debate surrounding the impact of intensive hog farms on the environment in North Carolina, the North Carolina Department of Environment and Natural Resources should make all water quality data available directly to the public and policy makers. This way, the policy debate can respectfully proceed from a common and factual basis, not the poison of endless contention.
