HR: 0830h
AN: H41D-1041    [PDF]
TI: Factors controlling net advection and longitudinal dispersion in the tidal Hudson River: Results from SF$_{6}$ tracer release experiments
AU: * Ho, D T
EM: david@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: * Ho, D T
EM: david@ldeo.columbia.edu
AF: Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027 United States
AU: Schlosser, P
EM: peters@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Schlosser, P
EM: peters@ldeo.columbia.edu
AF: Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027 United States
AU: Schlosser, P
EM: peters@ldeo.columbia.edu
AF: Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027
AU: Hellweger, F
EM: fhellweger@hydroqual.com
AF: Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027
AU: Caplow, T
EM: tc144@columbia.edu
AF: Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027
AB: Two large-scale tracer release experiments were conducted in the tidal Hudson River in the summers of 2001 and 2003 to determine net advection and longitudinal dispersion. During the experiments, ca. 4.3 moles of the inert gas SF$_{6}$ were injected into the Hudson River, several m above the bottom, near Newburgh, NY in 2001, and Hyde Park, NY, in 2003. After injection, the SF$_{6}$ was monitored from a boat using an automated measurement system for periods of 14 and 11 days, for 2001 and 2003, respectively. Longitudinal dispersion was more rapid in 2001 (70.1 $\pm$ 4.3 m$^{2}$ s$^{-1}$) than in 2003 (34.8 $\pm$ 2.1 m$^{2}$ s$^{-1}$), whereas mean advection was faster in 2003 (1.5 km d$^{-1}$) than in 2001 (0.5 km d$^{-1}$). At the end of the experiments, the SF$_{6}$ had spread to stretches of the river 100 and 60 km in length, in 2001 and 2003, respectively. Also, in 2001, the tracer moved further up river from the injection point, and asymmetry in tracer distribution was more pronounced. A numerical model of the Hudson River is used to simulate the tracer release experiments, and to determine the relative importance of various factors that contribute to the differences in the two experiments. The major external factors (e.g., river geometry, freshwater flow rate, tracer injection time with respect to the tidal cycle, and salinity distribution) that contribute to determining the tracer distributions will be discussed.
DE: 1803 Anthropogenic effects
DE: 1871 Surface water quality
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting