GROUNDWATER-SURFACE WATER INTERACTION IN CLEANED AND UNCLEANED STREAM REACHES, FISHING CREEK, SULLIVAN COUNTY, PA

Fall 2011 floodwaters altered stream channels and destroyed streamside and floodplain properties in the Northeast. In the wake of this devastation, many property owners “cleaned” nearby streams by dredging sediment, straightening channels, and removing woody debris. These modifications to stream channels likely changed both the extent and the function of the hyporheic zone. Piezometers in both cleaned and minimally disturbed reaches of the headwaters of Fishing Creek in Sullivan County, PA, are used to document the effects of post-flood cleaning on surface-groundwater interactions and ultimately, on nutrient processing. Twenty-one piezometers have been installed at depths ranging from 0.2-1 m in both cleaned and uncleaned reaches of the boulder-bed stream. Despite the coarse particle size at the stream bottom, hydraulic conductivity at depth varies widely. Approximately weekly water level measurements indicate that, at relatively low discharge, portions of both cleaned and uncleaned reaches are losing water to groundwater. Chemical analyses of surface and groundwater samples will shed more light on variations in hyporheic exchange and nitrate loss due to stream cleaning.