VARIATIONS IN SEDIMENT PHOSPHORUS FRACTIONATION ALONG AN ANTHROPOGENIC GRADIENT: EAST BRANCH CAZENOVIA CREEK, NY

Watersheds integrate processes that occur on the land surface in their catchment area and within the stream channel as sediment is transported through the system. The distribution of phosphorus within stream sediments may be influenced by a variety of factors throughout this continuum. This study focuses on an anthropogenic gradient found from the headwaters of the east branch of Cazenovia Creek to where is joins with the west branch in East Aurora, NY. The watershed shows a trellis drainage pattern with numerous small tributaries along its length. Eight sample locations were identified along the stream and sampled for sediment which was analyzed for P fractionation following a modification of the Psenner method. Land use within the watershed upgradient of each sample location was determined using Streamstats. Results show that the percentage of land in forest varied little throughout the watershed, typically ranging from 63 to 69 percent with one outlier. The percentage of urban land use and impervious surfaces was found to generally increase along the gradient. Phosphorus fractions were also found to vary, but not in a regular pattern with one exception. The sum of Al associated P and organic matter associated P was found to range from 192 to 336 mg/kg. There is an apparent progression of increasing P progressing from the headwaters downstream. The relationship between the sum of Al associated and organic matter associated P with urban land use or impervious surface area percentages is found to be significant with r² values of 0.69 and 0.63, respectively. These results suggest that urbanization and impervious surfaces have a large impact on stream sediment quality.