FECAL AND SEDIMENT PROBLEMS THAT OCCUR IN WATERSHEDS OF DIFFERING DEGREES OF DISTURBANCE IN THE PIEDMONT OF GEORGIA

Elevated (geometric mean > 200 colonies/100ml) fecal coliform bacteria are the most common cause of streams in the Piedmont of Georgia not meeting designated usages. Fecal coliform is an indicator of potential harmful bacteria in surface waters. Sources of harmful fecal coliform include wildlife, septic systems, leaking sewer lines, spray application of sewage, pets, and farmland. High sediment loads are often coupled with high fecal coliform levels. The streams of west Georgia are usually in the late youth stage of erosion – they have limited floodplains with much of the land in slope. The abundant slopes coupled with heavy rains, clear cutting, construction associated with urban sprawl and road building, and streams flowing through farmland cause excessive sediment influx into streams. Our research from 2001 and 2002 has found that both sediment (TSS and turbidity) and fecal coliform rise well above background levels in streams draining disturbed watersheds. For example, both the tiny Campus Branch (a tributary to the Little Tallapoosa River) and the Little Tallapoosa River have sharp increases in turbidity and fecal coliform. Both reach 4000-5000 col./100ml during large rainfall events. Large rain events cause turbidity of Campus Branch to increase from ~4 NTU to 160 NTU and the Little Tallapoosa River to increase from 14 NTU to 160 NTU. The Little Tallapoosa River drains a diverse watershed with abundant sources of bacteria and sediment. The Campus Branch drains the eastern heavily developed portion of the SUWG campus. For comparison, Hillabahatchee Creek is a relatively undisturbed watershed that flows through rural neighboring Heard County. Three sampling stations on the creek were monitored over the course of one year. Even after a large rainfall event (2 concurrent days with >1 inch of rainfall), turbidity values across the three stations averaged 19 NTU and fecal coliform values averaged only 68 col./100ml. Over the course of the entire year, turbidity averages across the 3 sample stations were 4.6 NTU, 5.7 NTU, and 10.6 NTU, while fecal coliform averages were 62 col./100ml, 43 col./100ml, and 72 col./100ml, respectively. Sources of sediment are easy to locate in the disturbed watersheds, however the source of high fecal coliform associated with high rain events is still under investigation.