Middle States Geographer, 2005, 38:45-51 THE EFFECT OF TEMPERATURE AND DISCHARGE RATES ON THE CONCENTRATION OF E.coli IN THE BUFFALO RIVER WATERSHED

ABSTRACT: Escherichia coli has the potential to cause human health problems as well as serving as an indicator of water quality. Temperature and flow rates of streams and rivers potentially impact the levels of E. coli present. The majority of research on E.coli levels has been conducted in warm weather months when the waterways are often used for recreational purposes. Bacterial input to stream sediments may occur during cold weather months and the sediment may act as a bacteria pool that can be resuspended by snowmelt or rainstorm events. The objective of this research was to determine the impact that temperature and discharge rates had on the levels of E.coli during cold weather months. E.coli levels, temperature, and discharge rates were measured once daily at three sites in the Buffalo River Watershed during early spring 2005. Enumeration of E.coli colonies was done using the Coliscan Easygel method. Results showed that levels of E. coli were lower (0-500 cfu/100ml and geometric mean of 32.19 cfu/100ml) than traditionally observed in the Buffalo River Watershed (up to 38,000 cfu/100ml during storm events) during warmer months. No correlation was found between the levels of E.coli present and temperature or discharge rates. Since these results are in contradiction to previous findings for the watershed, this study indicates that the water temperature, which averaged 5.5oC, was low enough to suppress levels of E. coli an