The Assessment of Rose Valley Lake

Rose Valley Lake is 369-acre man-made reservoir located in Lycoming County and managed by the PA Fish and Boat Commission for recreational fishing and boating. Since 2000, the Lycoming College Clean Water Institute (CWI) has been a partner with the Loyalsock Creek Watershed Association to complete the chemical and biological assessment of the lake. Carlson’s Trophic State Index (TSI) for lakes was created so that scientists can measure and record on a scale of 0 to 100. Each major division (10, 20, 30, etc.) represents a doubling in algal biomass. The index score/ calculation uses data on Secchi disk transparency, chlorophyll, and total phosphorus. These quantities and other biologically helpful nutrients are the primary factors of a body of water\u27s TSI. Nutrients such as nitrogen and phosphorus have a tendency to be limiting resources in standing water bodies, so amplified concentrations tend to result in increased plant growth, a body of water\u27s trophic index is used to make a rough estimate of a lakes biological condition. Over the last decade the lake has been changing from mesotrophic to eutrophic. This year the lake appears to be trending from Eutrophic to Hypereutrophic (TSI of 60-100).This trend indicates the lake is in transition from the highest amount of biological activity to possible reduction in water quality. In addition, zooplankton samples were taken and show a dominance of rotifers especially Keratella