PRECIPITATION INDUCED NUTRIENT LOADING VARIABILITY BETWEEN TWO TRIBUTARIES IN THE OWASCO LAKE WATERSHED, CENTRAL NEW YORK
Teledyne ISCO 6712 portable water samplers (R2D2) were installed near the terminus of both tributaries from 6-11-2013 through 7-9-2013. They were programed to collect 1-L of water every eight hours. The 24-bottle samplers were serviced weekly and each water sample was analyzed for total and dissolved P, TSS, dissolved silica, nitrates, alkalinity, conductivity, and pH by standard limnological methods. Stream stage was measured by a bubble logger at Dutch Hollow Brook and by a USGS stream gauge (04235299) just upstream from the Owasco Inlet site.
Both streams revealed varying amounts of nutrients and event signatures in TSS and P concentrations during the deployment. However, the magnitude and timing of the events were not consistent between the two watersheds. Variations in watershed geomorphology, land use, and rainfall may generate these differences, and precipitation variability is the focal point of this poster.
Daily rainfall data (www.CoCoRaHS.org) from stations within or near each watershed revealed that more rain (~1.7 times) fell over Dutch Hollow Brook than Owasco Inlet during the investigation, and the timing of the rain events differed as well. The rain events were consistent with the observed events in stream stage, TSS and P concentrations in each respective watershed but not between watersheds. It indicates that rainfall variability is large enough within the 523 km2 Owasco watershed to influence the timing and magnitude of suspended sediment and phosphorus loading to Owasco Lake. Future watershed/nutrient loading models might elucidate the relative contributions of geomorphology, land use and precipitation.