APPLICATION OF THE WATER QUALITY INDEX TO EVALUATE THE UPTAKE OF THE LOCK HAVEN PUBLIC DRINKING WATER SUPPLY, CLINTON COUNTY, PENNSYLVANIA

Surface water from the McElhattan Creek watershed serves as the source of drinking water for approximately 19,500 subscribers in Lock Haven area. The purpose of this study was to apply the Water Quality Index (WQI) to evaluate the source water within the system. Water samples were collected at five locations during the months of May through September in 2016-2018. HACH field and laboratory equipment were used to collect, process, and analyze data to evaluate baseline water quality. Data collected in 2016 served as a background dataset for understanding seasonal trends throughout the summer months, and provided insights into the changes in the system from one year to another. Field parameters included temperature, pH, conductance, TDS, and DO. Additional lab analysis yielded results for COD, BOD, NH₃-N, NO₃-N, NO₂-N, and total phosphorous. The WQI was calculated following the methods developed by Vicente et al. (2009). The WQI values were found to be above average for all five locations. Throughout the course of the study period, none of the parameters tested had values that warranted alarm when compared to the US EPA’s primary drinking water standards. On average, the values of NO₃-N and NH₃-N have increased during the study period. This increase led to concentrations which exceeded natural background concentrations during the summer months, but still were orders of magnitude less than the EPA’s maximum contaminant levels (MCLs).