HR: 13:40h
AN: H23G-01 INVITED     [Abstracts]
TI: Power-law behavior of transient storage residence time distributions from a multi-scale stream tracer test in Lookout Creek, Oregon
AU: * Haggerty, R
EM: haggertr@geo.oregonstate.edu
AF: Oregon State University, Dept. of Geosciences, 104 Wilkinson Hall, Corvallis, OR 97331-5506 United States
AU: Ninnemann, J
EM: ninnemaj@onid.orst.edu
AF: Oregon State University, Dept. of Geosciences, 104 Wilkinson Hall, Corvallis, OR 97331-5506 United States
AU: Gooseff, M N
EM: michael.gooseff@usu.edu
AF: Colorado School of Mines, Dept. of Geology and Geologic Engineering, 1516 Illinois St., Golden, CO 80401 United States
AU: Wondzell, S M
EM: swondzel@fs.fed.us
AF: U.S. Forest Service, Pacific Northwest Research Station, 3625 93rd SW, Olympia, WA 98512 United States
AB: We quantified the residence time distribution (RTD) of transient storage at increasing spatial scales in Lookout Creek at the HJ Andrews Experimental Forest, Oregon. A longitudinal tracer test was conducted with an in-stream injection of rhodamine WT over 78 hr, followed by monitoring at 7 locations (1-14 km downstream) for 5 months. Three additional tracer tests were carried out over shorter reaches, between each of the major stream confluences, to further quantify transient storage and to separate geomorphic variability from other possible scale-dependent factors. The results clearly show power-law RTDs (i.e., $c \sim t^{-k}$), but not a single, "universal" RTD or scaling relationship. The exponent, $k$, ranges from 1.35 to 2.0, and appears to decrease downstream. Observed changes in the power-law RTD may result from characteristic changes in channel morphology or the degree of geomorphic complexity, which are related to stream size. Downstream reaches exhibit a larger delay between the peak concentration and power-law tailing compared to upstream reaches, possibly indicating a smaller hyporheic zone relative to stream size.
DE: 1824 Geomorphology (1625)
DE: 1829 Groundwater hydrology
DE: 1845 Limnology
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting