Agricultural land use impacts on bacterial water quality in a karst groundwater aquifer

The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Reg ion. Karst areas comprise about 18 percent of the Region's land area. An es timated one-third of the Region's farms, cattle, and agricultural market va lue are on karst terrain. The purpose of this study was to compare fecal ba cteria densities in karst groundwater impacted by two primary agricultural land uses in central Appalachia. Fecal bacteria densities were measured in cave streams draining two primary land management areas. The first area was pasture serving a beef cow-calf operation. The second area was a dairy. Ne ither area had best management practices in place for controlling animal wa stes. Median fecal coliform and fecal streptococcus densities were highest in cave streams draining the dairy. Median fecal coliform densities in the daily-impacted stream were greater than 4,000 CFU/100 ml and the median fec al coliform densities in the pasture-impacted streams were less than TO CFU /100 ml. Median fecal streptococcus densities in the same streams were grea ter than 2,000 CFU/100 ml and 32 CFU/100 ml, respectively. A second dairy, with best management practices for control of animal and milkhouse waste, d id not appear to be contributing significant amounts of fecal bacteria to t he karst aquifer. It was concluded that agriculture was affecting bacterial densities in the karat aquifer. New management practices specifically desi gned to protect karst groundwater resources may be one way to protect the g roundwater resource.