Urban streams are reflections of the landscapes and environmental pressures that surround them. In the Mohawk River Watershed, tributary streams endure various levels of human influence, ranging from urban to rural and even agricultural land use. Our study explores how human-induced pollution, with a focus on sewage and road salt, impacts water quality and ecological health across the watershed, with a specific focus on the Hans Groot's Kill (HGK), an urban stream in Schenectady that runs through Union College's campus. Historically, the HGK ran through forested land but is now mainly restricted to an urban drainage network that receives inputs of sewage and stormwater runoff from surrounding infrastructure. Previous research has recorded high bacterial contamination, elevated chloride from road salts, and microplastic pollution within the stream. To better understand water quality across the Mohawk Watershed, we sampled eight streams representative of a gradient of human influence, including rural streams like Wilsey Creek and urban streams including Kromme Kill and HGK. We collected water quality and pathogen data during spring and summer 2025 measuring salinity, temperature, dissolved oxygen, and Enterococcus concentrations. We also sampled benthic macroinvertebrates with three D-net samples at each stream to examine ecological health. Results uncovered strong spatial and seasonal patterns in contamination. Enterococcus levels increased dramatically from spring to summer, from a seasonal average of 18 mpn /100 mL in the spring to over 900 in the summer. Furthermore, urban streams like HGK had the highest salinity and pathogen levels (far exceeding recreational thresholds) and were dominated by pollution tolerant taxa such as black flies and scuds. Meanwhile rural streams supported diverse communities of taxa of varying pollutant-sensitivity like mayflies and stoneflies. Preliminary analysis suggests that streams with high Enterococcus levels have lower diversity of benthic macroinvertebrates. Overall, our findings imply that intense land use and aging infrastructure contribute to shaping water quality across the Mohawk Watershed. The association between pathogen contamination, salinity, and decreasing biodiversity underlines the need for infrastructure repair, refined stormwater management, and less road salt usage to preserve stream ecosystems and human health.
Acknowledgements: Peter R. Brayton Summer Research Fellowship