NUTRIENT AND SEDIMENT LOADING TO RAYSTOWN LAKE DURING BASE AND STORM FLOW

Understanding the rate of nutrient and sediment input into reservoirs is important in understanding and predicting water quality and nutrient cycling. The highest rates of input typically come from tributaries, and factors determining nutrient and sediment loading may include size of the watershed, rates of discharge and land use. A baseline study was conducted on the Raystown Branch of the Juniata River above Raystown Lake in central Pennsylvania during the summer and fall of 2005. Two major tributaries to the Raystown Branch, including Dunning Creek and Yellow Creek, were sampled, as well as one site on the Raystown Branch below the input of both streams at Saxton, PA. Nitrate concentrations tended to increase during storm events at Dunning Creek and Saxton, and decrease at Yellow Creek, suggesting that nitrates enter the system differently on each tributary. Yellow Creek had the highest nitrate concentrations, and contributed a greater nitrate load to the Raytown Branch. Total phosphorous concentrations usually increased during storm events at all sampling sites. Dunning Creek had the highest total phosphorous concentrations although the total phosphorous load was very similar to Yellow Creek. Total suspended solids increased during storm events, and each sampling site showed similar concentrations.