Alternative methods for fecal coliform load reductions in Suth Gorgia watersheds

Section 303(d) of the Clean Water Act requires an assessment by the states of streams, rivers, and other water bodies within their borders which do not meet set water quality standards. Of the 11,285 miles of streams and rivers assessed in the state of Georgia, roughly 57% have been classified as impaired. Of the impaired water bodies, impairments due to fecal coliform (FC) bacteria are the most prevalent form of pollutant. Fecal coliform bacteria are found in both urban and rural settings. Pathogenic microorganisms associated with FC bacteria pose a great risk to human health. The Suwannee River stretches from south-central Georgia to the Gulf of Mexico in Florida and is the only major waterway in the southeastern U.S. that is still unspoiled. Of the 86 streams that are on the 303(d) list of noncompliant waters for the Georgia portion of the Upper Suwannee River Basin, 15 of the streams are impaired due to FC bacteria. Here we examine the impact of in-stream FC sources and natural buffers in impaired segments of the Georgia portion of the Upper Suwannee River Basin through simulation with the SWAT model. Data from the 16.7 km² watershed K of the Little River Experimental Watershed located near Tifton, Georgia were used. Our preliminary results indicate that while the SWAT model replicated the timing of some peak bacterial concentrations in watershed K, the timing and magnitude of several of the predicted FC concentrations differed considerably from the observed. Simulations indicate that riparian buffers within the watershed significantly decrease the bacterial loading to the stream. These simulations also indicate that the most significant contributor to bacterial concentrations within the watershed is the direct input of FC from wildlife sources into the stream.