WATER QUALITY INDEX ASSESSMENT OF THE HEADWATER SYSTEM FEEDING THE LOCK HAVEN PUBLIC DRINKING WATER SUPPLY

Surface water within the McElhattan Creek watershed serves as the source of drinking water for 19,590 subscribers of the Central Clinton County Water Filtration Plant in Pennsylvania. The purpose of this study was to determine the water quality index for the source water within the system.

Grab samples of water were collected at 5 locations on a monthly basis from May to September, 2016. A Hydrolab MS5 MiniSonde and HACH field and laboratory equipment were used to collect, process, and analyze data to evaluate baseline water quality. A primary objective of this study was to determine total organic carbon concentration, due to its importance for the final outcome of the treatment process. Field parameters included temperature, pH, conductance, TDS, DO, ORP, and chlorophyll-a. Additional lab analysis yielded results for COD, BOD, TOC, hardness, alkalinity, NH₃-N_, NO₃-N, NO₂-N, PO₄-P, Cl^-, and SO₄^-2. Water Quality Index (WQI) was calculated using the results (Vicente et al., 2009).

The WQI values were found to be excellent. Throughout the course of the study period, none of the parameters tested had values that warranted alarm when compared to the EPA’s primary drinking water standards. The highest observed NO₃-N values were less than 1/10 the MCL for drinking water; other parameters showed results that were also below those suggested by the EPA. On average, the values of nutrients, such as NH₃-N and NO₃-N were below or equivalent to the natural background levels suggested by the USGS literature (U.S. Geological Survey, 1999). The toxicity levels in terms of heavy metals in sediment samples collected were also less than the probable effect levels published by the EPA (Ingersoll et al., 2000).