HR: 1330h
AN: B33E-17    [Abstracts]
TI: Hyporheic Hydrology of the Umatilla River: Interactions among Physical and Biological Drivers
AU: * Jones, K L
EM: kjones@eco-metrics.com
AF: Eco-metrics, Inc., 2520 Pine Lake Rd, Tucker, GA United States
AU: Vitale, M V
EM: mvitale@ntcd.org
AF: Eco-metrics, Inc., 2520 Pine Lake Rd, Tucker, GA United States
AU: Poole, G C
EM: gpoole@eco-metrics.com
AF: Eco-metrics, Inc., 2520 Pine Lake Rd, Tucker, GA United States
AU: Poole, G C
EM: gpoole@eco-metrics.com
AF: Institute of Ecology, University of Georgia, Athens, GA United States
AU: Boer, B R
EM: brian.boer@umontana.edu
AF: Department of Geology, University of Montana, Missoula, MT United States
AU: Thomas, S A
EM: sat43@cornell.edu
AF: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY United States
AU: Woessner, W W
EM: gl_www@selway.umt.edu
AF: Department of Geology, University of Montana, Missoula, MT United States
AU: O'Daniel, S J
EM: sodaniel@icess.ucsb.edu
AF: Confederated Tribes of the Umatilla Indian Reservation, PO Box 638, Pendleton, OR United States
AU: O'Daniel, S J
EM: sodaniel@icess.ucsb.edu
AF: Department of Geography & ICESS, University of California, Santa Barbara, CA United States
AB: The hydrology of the hyporheic zone in the upper Umatilla River (Oregon, USA) is highly dynamic, due to the river's complex channel geometry and largely unregulated discharge regime. Coarse-scale variation in patterns of water exchange between the river channel and hyporheic zone are mediated by inundation and abandonment of flood channels during freshets. Our research, however, documents an important biological driver of hyporheic hydrology. Spring channels (perennial channels that derive their flow from hyporheic and/or phreatic water) on the flood plain provide excellent habitat for emergent aquatic vegetation during the summer. Plant growth increases flow resistance and alters the relationship between spring channel discharge and stage, influencing the water table elevation near the spring channel. Thus, the seasonal growth and senescence of emergent aquatic vegetation influence the rate and pattern of hyporheic discharge to the spring channel, affecting the hydrology of the hyporheic zone across the entire flood plain. Thus, our data provide a novel illustration of functional feedback between physical and biological processes, which ultimately contributes to habitat diversity within lotic ecosystems.
DE: 1824 Geomorphology (1625)
DE: 1829 Groundwater hydrology
SC: Biogeosciences [B]
MN: 2005 Joint Assembly