Characterization of Water Quality of a PumpedStorage Facility

We characterized the water quality (water temperature, dissolved oxygen (DO), pH, chlorophyll a, specific conductivity, and turbidity) of the Muddy Run Pumped Storage Facility located on the lower Susquehanna River in 2010 and 2011 and analyzed the effects of project operations on these parameters, particularly during summer low flow period. We systematically sampled depth profiles in April through October and took continuous measurements (except for chlorophyll a) in the immediate forebay and the tailrace of the project. The water quality of the upper storage reservoir, to a large extent, is reflective of prevailing conditions in the lower reservoir (Conowingo Pond, source water) due to daily exchange of water between the two bodies of water though some differences occur in vertical distribution of DO. As in the past, some deep areas in the upper storage reservoir showed vertical stratification (mostly in late July through August). No thermal stratification was observed. Relative to the historical records, little changes were observed in water quality characteristics of the reservoir. Although substandard DO values (daily average # 5.0 mg/L and instantaneous value # 4.0 mg/L) were recorded at both continuous monitors; mainly during July-August period their occurrences could not be conclusively correlated with project operations. However, an increase in DO at the continuous monitor in the immediate forebay area during pumping mode was noted, perhaps a reflection of withdrawal of high DO water from the lower reservoir. The influence of substandard DO was limited to the turbine discharge area during generation. Even though the upper reservoir exhibits DO stratification, the tailrace instantaneous DO measurements of \u3c4.0 mg/L occurred only once (0.2%) and no daily average DO values were less than 5.0 mg/L meeting the PA DEP standard. Simultaneous measurements of water temperature taken at different operational modes did not show discernible effects of project operations. Both the turbidity and pH values met the PA DEP water quality standards and were within the historical range