Water Quality of the Kromme Kill and Collins Lake System, Scotia and Glenville, New York: Impairment Due to Septic Failure and Salinization

The Northeast United States is plagued by road salt pollution in waterways and aging infrastructure, which are both contributors to poor water quality. This study is focused on the Kromme Kill and Collins Lake, the only two waterways on the Great Flats Aquifer, an important source of municipal water in Schenectady County (NY). Forty-nine samples were taken during the fall of 2023. Sampling was done regularly, during both high- and low- flow conditions, but the fall was relatively dry, so most samples reflect low-flow. Samples were analyzed for dissolved ions, fecal-indicator bacteria Enterococcus, and physical water quality parameters. The highest Enterococcus values occur at high flow. The EPA's Beach Advisory Value (60 mpn/100 ml) was exceeded 80% of the time (39/49) in both high- and low- flow conditions. The eastern Kromme Kill is the most impaired with five-week geometric means of 372 to 598 mpn/100 ml. The highest chloride (Cl-) concentrations occur at low flow on the aquifer and this reflects the salinity of the aquifer. Mean chloride in the eastern Kromme Kill was between 167 and 197 mg/l. Six out of the eight sites (75%) exceeded 120 mg/l, which is a threshold that may still be too high for aquatic ecosystem health. Chloride concentrations of Collins Lake are high and increasing over time. Chloride in Collins Lake was stable throughout the study at ~123-124 mg/l. Historically, Cl- concentrations have been much lower: ~53 mg/l in 1984 and ~95 mg/l in 2011 and thus Cl- in Collins Lake appears to have increased 2.3 times (~130% increase) in the past forty years. This study shows that road salts (NaCl) and pollution from sewage are the two main impairments to the system that includes surface waters and the aquifer. Individual septic systems are likely the source of these high pathogen numbers in Glenville, and the Town should consider extending municipal sewage lines. Road salts from de-icing roads in the winter and salt barns contribute to high salinity (sodium and chloride) in the system. The Kromme Kill is in a unique position at the edge of the permeable part of the Great Flats Aquifer, so poor water quality of this stream has implications for the drinking water of surrounding municipalities. Solutions include reduced salt storage in the winters, moving salt storage that is on the aquifer, and continued water quality monitoring of the aquifer and surface water bodies.