HR: 08:15h
AN: H51J-02    [Abstracts]
TI: Overland flow caused by groundwater springs in the Catskill Mountains, New York, USA
AU: * Harpold, A A
EM: aah38@cornell.edu
AF: Cornell University, 30 Riley Robb Hall, Ithaca, NY 14850, United States
AU: Steenhuis, T
EM: tss1@cornell.edu
AF: Cornell University, 30 Riley Robb Hall, Ithaca, NY 14850, United States
AB: Groundwater springs have been shown to be important for baseflow maintenance, ecological diversity, and biogeochemical transport in the Catskill Mountains of New York State. A study was undertaken to evaluate the importance of groundwater springs to stream flow response, spatial distribution of saturated areas, and chemical transport on a 2 km2 watershed. Discharge and water chemistry were monitored at five upland springs and the watershed outlet during three storm events and weekly for one year. The spatiotemporal connectivity of groundwater springs to the stream was evaluated using the isotopes, conservative geochemical tracers, groundwater heights, temperature probes, and soil moisture measurements. The data indicates that spring discharge is capable of maintaining isolated areas of saturation and overland flow that provide hydrologic connections between upland hillslopes and the stream. Thus, upslope springs can be important sources of solutes and nutrients, especially during baseflow periods. The response of the individual springs was correlated to the upslope contributing area during large rain events. However, terrain indices were not capable of predicting relative spring discharge during moderate to dry conditions. The results suggest that two geomorphologic wetness states exist for this Catskill watershed: 1. during wet antecedent conditions surface topography is a first- order control on water table heights and overland flow, 2. during dry to average antecedent wetness conditions geomorphologic heterogeneities (e.g. bedrock fractures and confining layers) control locations and extent of saturated areas and overland flow. The two-state wetness system hypothesis has important ramifications for developing watershed-scale parameters (i.e. drainage density) and spatial modeling in heterogeneous landscapes.
DE: 0496 Water quality
DE: 1826 Geomorphology: hillslope (1625)
DE: 1830 Groundwater/surface water interaction
DE: 1850 Overland flow
SC: Hydrology [H]
MN: 2007 Fall Meeting