Poultry Operations Special Study
The Cypress Creek Basin CRP uses special studies to deal with specific water quality issues or to support other programs (i.e., TMDL development) addressing water quality issues in the basin.
A special study was implemented within Cypress Creek Basin that addressed the possible water quality impacts of poultry production operations. This special study was an extension of the a previous study that was conducted during 1997-1998 that compared water quality characteristics among nine sample locations in four tributary watersheds which were monitored on a monthly basis. This Cypress Creek Basin Clean Rivers Study was extended, to sample the four most downstream stations on Frazier, Lilly, Prairie and Boggy Creeks which were investigated during the original TNRCC poultry operations study. A fifth location was selected on the lower portion of Walkers Creek to begin water quality data collection downstream of the proposed Pilgrim's Pride Corporation Walker Creek Poultry Processing Facility. The data obtained during this monitoring effort was used to evaluate inter-annual variability and look for long term water quality trends in the poultry study watersheds, and to establish a baseline data set for Walkers Creek before the facility began discharging.
The reference streams selected for monitoring, Boggy and Frazier Creeks, were selected by TNRCC in 1997 on the basis of similarity to the study sub-watersheds in size, rural character, absence of point source discharges, and contrasting low levels of poultry production activity. Lilly, Prairie, and Boggy creeks are located in an area where agricultural development has taken place on a mosaic of woodland and native prairie. Monthly measurements of field parameters, and conventional parameters were collected from October 1999 through June 2001. Habitat and biological surveys were conducted in August 2000 and August 2001.
Information provided by Pilgrim's Pride Corporation indicated that both poultry production (litter production) and land disposal of litter had declined in all four sub-watersheds. Although substantial changes in actual poultry production and litter disposal activities, particularly in the Lilly and Prairie Creek sub-watersheds, occurred between the two study periods, little evidence of change in water quality parameters measured at the four Poultry Study stations was found. The newly added Walker Creek station, which monitored runoff from Pilgrim's Pride Corporation processing plant construction and from a level of poultry production and litter disposal activity similar to that of adjacent sub-watersheds during the Special Study period, has many water quality similarities with the nearby Lilly and Prairie Creek stations.
No trends over time were evident in any of the data examined, and nutrient parameters, chlorophyll a, and dissolved oxygen exhibited similar patterns among stations during both study periods. Total phosphorous and nitrate+nitrite nitrogen were present in Frazier Creek in significantly lower concentrations than at the other stations (except Boggy Creek). Conversely, chlorophyll a, ammonia nitrogen, and total kjeldahl nitrogen did not show any significant differences among stations, although screening exceedances, median values, and distributions of maximum values continued to suggest that the more agriculturally developed sub-watersheds carry higher nutrient loads and experience more intense biological activity.
Frazier Creek is distinct from the other four streams sampled in the Special Study with regard to water chemistry parameters such as total dissolved solids, specific conductance, alkalinity, chloride, hardness and sulfate that tend to be less likely to be influenced by land use practice short of intense urbanization.
The Aquatic Life Use (ALU) scores based on the fish and benthic macroinvertebrate community composition at all five Special Study streams have shown no real change from the values seen during the 1997-1998 study and remain in the range between the Intermediate and High integrity classes. Examination of the fecal coliform data results indicate both minimum and maximum concentrations were lower during the 2000-2001 sample period than during the initial study. This improvement was attributed possibly to the relatively lower streamflow regime that characterized the 2000-2001 sample period, rather than the general decrease in land disposal of chicken litter.