The environmental research team assigned by the University of Arkansas Division of Agriculture to monitor nutrient and bacteria levels surrounding a controversial Newton County hog farm has released its third quarterly report.
The Big Creek Research Team, headed by Andrew Sharpley, and professor of soils and water quality at UA, was formed last year in reaction to continued public outcry over the Arkansas Department of Environmental Quality’s decision to issue an operational permit to C&H Hog Farms, a large-scale swine concentrated animal feeding operation in Mount Judea. The farm, which is permitted to house approximately 2,500 full-grown sows and as many as 4,000 piglets, abuts Big Creek about 6 miles upstream from its confluence with the Buffalo National River.
Researchers with the team began gathering weekly water samples from four points along Big Creek last September. The sampling points are upstream and downstream of C&H Hog Farms’ production facility and the surrounding grasslands upon which the farm owners are permitted to spread the animal waste generated by their hogs.
Although the quarterly report notes generally stable levels of contaminants in the creek, levels of E. coli were shown to spike significantly after storms in mid-May, just as they had in November. According to the Arkansas Pollution Control and Ecology Commission’s Regulation 2, which governs state water quality standards, between May 1 and Sept. 30, levels of E. coli should not exceed 400 colonies per 100 milliliters of water in areas used for swimming, canoeing or other activities where individuals come into direct contact with the water.
Samples taken May 13 show E. coli levels as high as about 920 colonies of E. coli upstream from the farm, and as high as about 1,553 downstream from the farm. By the next collection date, May 19, the levels had again dropped to well below the state limitations, ranging from about 27 colonies to about 205 colonies.
Van Brahana, a retired UA professor of hydrology, who has been conducting his own water quality sampling in Big Creek and the Buffalo National River, said that as more manure is applied to the grassland — much of which is already saturated with phosphorus and other nutrients from decades of fertilizer application — instances of nutrient and bacterial runoff into area waters will continue with each rain.
“If you overload a field, then many of those additional components are going to be moved downstream,” Brahana said. “If they get into low-velocity flows or reservoirs, those can create some significant problems with oxygen.”
Nutrients such as phosphorus can lower the levels of dissolved oxygen in water, promoting algae growth, and suffocating fish and other aquatic wildlife.
In an email Friday, Sharpley said that in areas where phosphorus content is already high, manure will be applied at a reduced rate, if at all.
“The term ‘very high’ is qualitative and there is a limit of soil phosphorus, which when exceeded will not allow any application of [phosphorus], be it as hog slurry, poultry litter, or commercial fertilizer,” Sharpley said. “That threshold or limiting soil phosphorus varies from field to field based on such relevant site factors as field slope, proximity to the stream, erodibility, and potential for runoff to occur.”
Sharpley and his team are also considering the promotion of “alternative manure management strategies,” including treating the animal waste with low-cost, locally available materials that will “render the phosphorus in the manure less soluble or environmentally less reactive either before it reaches the lagoon or in the lagoon itself,” Sharpley said.
The report also outlines the use of ground-penetrating radar on one of the 17 grassland fields surrounding the farm. Because most of Newton County has a karst geology, where porous limestone underlays typically less than a yard of soil, critics of the farm have voiced concern that nutrients may eventually percolate through the soil, and eventually into the groundwater, especially if there are large fissures in the karst near the farm.
Sharpley described the findings of the radar as being “useful,” but “not spectacular” during a presentation Wednesday at the Arkansas Water Resources Center’s annual water conference in Fayetteville. The results discussed in the study described typical karst formations with no remarkable abnormalities.
The report concludes with a checklist of future plans for the research team, including the installation of automated water sampling equipment in Big Creek, which will be useful in collecting real-time data during storms. The report says the team will also install a “subsurface flow collector trench” near the farm’s outdoor lagoons, where animal waste from the two large barns is stored until it is either spread as manure or transported off-site.
The trench, which has already been dug down-slope of the lagoons, will help measure whether nutrients and bacteria are being washed onto the nearby grounds from the lagoons during rains, or are leaking into the ground after permeating the lagoons’ clay liners.