SUMMER-SEASON ENVIRONMENTAL ASSESSMENT OF SLIPPERY ROCK CREEK

The purpose of this project was to conduct an environmental assessment of Slippery Rock Creek in Butler County, Pennsylvania. As a tributary of Connoquenessing Creek, a highly polluted stream, Slippery Rock Creek warranted analysis as to its environmental characteristics. On a weekly basis over a three month period, water quality data were collected along 2.5 kilometers of the stream. The types of data included dissolved oxygen, pH, temperature, turbidity, flow rate, discharge and bacterial testing. The testing was conducted upstream, downstream, and along an intervening densely populated urban area to determine if and how the stream was influenced by environmental changes en route. Dissolved oxygen was tested by colorimetric analysis and pH was monitored using Hydrion paper. Temperature was monitored with a digital thermometer while turbidity was tracked qualitatively using a secchi disk. A flow meter recorded average flow velocities across upstream and downstream sites that were used as reference sections to calculate flow (Q) into and out of the stream reach under different stages. Bacterial tests were administered upstream and downstream of the urban area, and were taken in both high and low flow conditions. The project yielded both predictable and surprising results. Water temperature rose steadily throughout the summer and then declined beginning in the second week of July as weather patterns shifted. Testing revealed the presence of possibly harmful bacteria, both upstream and downstream of a densely populated area, under both high and low flow conditions. The stream also consistently gained water, at an average of sixteen percent by volume, via the input of groundwater and small tributaries along its length. While turbidity and pH remained fairly constant, dissolved oxygen rose over time, even as temperature rose, while maintaining steady levels throughout stream length. An increase in the amount of green algae in the water, or groundwater input, may have contributed to the latter.