A HYDRO-GEOCHEMICAL APPROACH TO DETERMINING SURFACE AND GROUNDWATER CONTRIBUTIONS TO THE FULLER HOLLOW CREEK WATERSHED, BINGHAMTON, NEW YORK

Located in an incised river valley in south central New York, the Fuller Hollow Creek Watershed (FHCW) receives atmospheric and hydrologic input from urban, residential, and natural sources, as well as direct impacts from Binghamton University’s (BU) campus activities. The upper portion of the watershed encompasses the BU Nature Preserve, an undeveloped area, which contains a network of three beaver ponds, while the lower portion of FHCW is urbanized, and contains several culverts and a large storm water retention pond (Lake Lieberman) that captures runoff from campus. In recent years, spread of urbanization in FHCW has replaced large portions of forests, streams, and fields that were capable of absorbing precipitation with impervious surfaces. The increase in impervious surface area has led to an increased amount of flash flooding throughout the FHWC during rainy seasons, and insufficient stream flow during dry seasons, both of which may result in ecosystem impairment.

The purpose of this study was to devise a hydro-geochemical approach that enables the determination and quantification of surface and groundwater contributions to the stream flow within the FHCW. Then, through study of runoff and geochemical interactions between surface and groundwater, controls on water quality in discharge from the FHCW were determined. Seven surface water and eight groundwater sampling sites were used to evaluate fluxes in source contributions throughout the watershed. All water samples were analyzed for temperature, pH, and conductivity, as well as cation and anion concentrations in dissolved and particle bound forms. A multi-component differential mass balance model was then employed to determine which source component has the greatest effect on FHC on a temporal and spatial basis. Preliminary results indicate that surface runoff exhibits the dominant control on water quality in the winter and spring, while groundwater controls water quality during the summer and fall.