SEASONAL WATER QUALITY MONITORING ALONG FOURMILE CREEK, ERIE, PENNSYLVANIA

Poor water quality can have a negative impact on aquatic organisms and on human use of the water resource. Stream contamination tends to be greater in bodies of water that flow through or near urbanized areas, and can result in increased growth of bacteria and algae. In NW Pennsylvania, poor stream-water quality can be reflected in changes to salinity, turbidity, and pH. Urban-related stream pollution can be expected to vary seasonally from changes in runoff, precipitation, fertilizer application, and road salt application.

The purpose of this research project on the southern perimeter of the Lake Erie drainage basin was to identify the stream bacteria in, and the pH, turbidity, and salinity characteristics of, Fourmile Creek as it passes from an upland natural environment through an increasingly urbanized area into Lake Erie. Weekly samples were collected and analyzed from four established sites along the creek during the spring through fall seasons of 2011. Salinity and stream temperature were monitored using a YSI Model 30 Conductivity, Salinity, and Temperature System. Stream velocity was determined using a Global Flow Probe. Turbidity was calculated using a Total Dissolved Solids method. Bacterial species were identified using DNA sequencing. Bacterial colonies were grown for 24 hours at 37⁰C in petri dishes containing agar to determine species diversity and total number of bacteria. Stream pH was determined using an electrode device.

Data show that the pH of the stream ranged from 6 to 9 and that the salinity ranged from 0.1 ppt to 0.3 ppt. Bacterial species varied between drought and flood conditions with Aeromonas veronii characterizing poor water-quality conditions during drought and flood periods. Results revealed that Aeromonas veronii is a temperature-sensitive bacterium that thrives in warmer temperatures. Stream hydrodynamics monitoring revealed that the average flow velocity was maximized during flood periods at 125 cm/s and was significantly lower during drought periods at 5.1 cm/s. Stream discharge (Q) under these conditions was 91x10³ cm³/s and 1.4x10³ cm³/s, respectively.