THE AGRICULTURAL INFLUENCE ON WATER QUALITY IN STREAMS OF THE WEST GEORGIA REGION

The west Georgia area is a region of extensive agriculture and forests, with cattle and chicken farms being the most abundant forms of agriculture. Fertilization and waste disposal practices in conjunction with rainfall events may influence water quality. Popular commercial fertilizers contain ammonia, phosphorus, and nitrates. Chicken litter is another popular form of fertilization which may affect fecal coliform and phosphate, nitrate, and ammonia levels. Pastures in which cattle are overloaded or allowed direct access to streams may also contribute to elevated fecal coliform levels. This study was conducted to determine the extent of agriculture’s affect on water quality and what key agricultural practices have the most effect.

In order to understand agricultural influences on streams in the area, various agricultural and non-agricultural streams were selected for comparison in 2003. The seven water quality parameters associated with agricultural influence (dissolved oxygen, turbidity, total suspended sediments, fecal coliform bacteria, nitrite-nitrate-N, ammonia-N, and total phosphorus) were collected during base flow and rainfall events at both agricultural and non-agricultural streams. Hillabahatchee Creek, a pristine woodland stream in the Chattahoochee River drainage basin, was selected as a non-agricultural site. Many other streams in the Tallapoosa watershed with varying degrees of agricultural development were selected to represent agricultural sites.

Results indicate that agricultural streams experienced elevated fecal coliform during rainfall events. The 2001 West Georgia Watershed Assessment (WGWA) found average fecal coliform levels in Mud Creek, Yellowdirt Creek, and Turkey Creek (agricultural streams) to be 950 col/100mL, 140 col/100mL, and 120 col/100mL respectively. Hillabahatchee Creek (non-agricultural stream) was found to have an average fecal coliform level of 43 col/100mL. Results from ammonia, nitrate-nitrite-N, and phosphorus analyses showed that the agricultural streams were only slightly elevated. However, Yellowdirt Creek had an average nitrite-nitrate-N level of 0.9 mg/L and an average phosphorus level of 0.5 mg/L, while Hillabahatchee Creek had an average nitrite-nitrate-N level of less than 0.1 mg/L and an average phosphorus level of 0.2 mg/L.