Fecal Indicator Bacteria indicate impairment of surface water quality in the Indian Kill Watershed in the Town of Glenville, New York

Surface water such as streams, rivers, and lakes are important for drinking water and recreation. Water quality of the Mohawk River may be impaired by these local tributaries, including the Indian Kill, which flows through the town of Grenville into the Mohawk. Water quality of the Indian Kill was studied in the Spring of 2022, by sampling water at nine locations in both urban and rural settings. At each site, weekly measurements were taken on water quality parameters (using YSI), fecal indicator bacteria (FIB using Enterococcus), and dissolved ions (ion chromatograph).  During low flow conditions, base flow from groundwater reveals contamination from septic systems enters this stream. During high flow conditions, septic systems appear to be overwhelmed resulting in high pathogen loads. Under both high flow and low flow conditions, stream segments of the urban areas of the Indian Kill exhibited conditions which exceeded the EPA level for contamination of fecal indicator bacteria. The geometric mean of FIB rural sites, which drain into the urban area is 9-12 mpn/100ml. However, once the stream passes through the urban area FIB levels increases to 33 - 138 mpn/100ml. Of particular concern is a short segment called Mayfair that has the worst water quality evaluated (138 mpn/100ml). Stream sites in Urban areas exhibited high levels of nitrates, sulfates, phosphates, sodium, and chloride. Sodium and chloride appear to be particularly highly correlated and have the highest values in urban groundwater (Cl- 125-175 ppm, Sodium Na+ 75 - 110 ppm), and this is probably related to road salt contamination. The widespread use of septic systems appears to affect groundwater, as indicated by high levels of nitrates. Mitigation likely involves public education as well as the slow transition from septic systems to sanitary sewers.