Multimetric approach in the effects of small impoundments on stream water quality: Case study of Faylor and Walker Lakes on Middle Creek, Snyder County, PA

Abstract

AbstractIn recent years, dams have received extensive scrutiny for their effects on stream and river systems throughout the United States. Dams vary greatly in size and scale, but investigations often focus on large‐scale dams due to their visibility in the public eye and pronounced impact. This can result in smaller and less impactful impoundments being overlooked, despite the cumulative effects these dams can have on higher order aquatic systems. Two small water impoundments: Walker and Faylor Lakes located, respectively, on the north and west branches of Middle Creek in Snyder County; Pennsylvania have demonstrated an impact on Middle Creek. This study focused on using onsite physical properties, grab samples for chemical analysis and macroinvertebrate samples to determine and compare the effects of the two impoundments on Middle Creek. Both upstream and downstream sites from the dams were sampled. All sites were sampled for physical variables using the YSI Multimeter and chemical concentrations of several cations and anions using Ion Chromatography (IC). A Water Quality Index (WQI) was constructed based on 11 different parameters. All parameters were positively correlated. Data show that the physical and chemical changes to the streams, are caused by the dams and are affecting the biological communities in the downstream water course. Walker Lake was found to have a much greater negative impact on the north branch of Middle Creek causing degradation to the water in relation to certain parameters. Greater concentrations of NH4+, BOD5 and a decreasing WQI downstream of the Walker Dam, as well as several different macroinvertebrate indices indicate this negative impact. Faylor Lake Dam did not have a large impact on the west branch of Middle Creek with regard to any particular variable measured. Overall, small reservoirs can have substantial impacts on the streams they impound especially when considering the morphology and design.