Longitudinal Study of Water Quality in Jennings Creek, Bowling Green, Kentucky: Urbanization Impacts on Karst Groundwater

Karst groundwater systems, which occur in areas where caves, sinkholes, and underground rivers dominate the landscape, are vulnerable to pollution from surface contaminants. In urban areas, like Bowling Green, Kentucky, which is home to extensive caves and groundwater supplies, the immediate transport of heavy metals, organic waste, chemicals, and other pollutants from surface activities into groundwater poses a serious threat. This research project was done to examine the water quality of urban karst sites in Bowling Green, Kentucky at Jennings Creek, which is a local river primarily fed from springs; the water quality of Jennings Creek was never tested before this project, although it is an input to the Barren River, the area’s primary drinking water source. Weekly water samples were taken at five sites for six weeks over the summer. Each sample site was selected based on its proximity downstream from a primary spring input with a known drainage area and land use. The samples were tested each week for forty-three different parameters related to water quality, which included alkalinity, total organic carbon (TOC), cations, anions, metal concentrations, dissolved oxygen, total chlorine, and E. coli, among others. The results of the data collected indicate different pollutant concentrations based on land use in the area surrounding the spring inputs, with major detrimental changes occurring at the largest spring inputs. The sites in mixed land use areas (agricultural and residential) had more nitrates and phosphate, while urban areas suffered from more industrial waste and metal contamination. Overall, nearly every site exceeded the EPA drinking water quality standard for several parameters, including nitrates, E. coli bacteria, and several metals, indicating that more research is needed to address the primary causes of these contaminants and better practices to mitigate their input into the groundwater system.