HR: 0800h
AN: H41A-0136    [Abstracts]
TI: Channel Reconfiguration Impacts on Solute Transient Storage Dynamics in the Provo River, Utah
AU: * Gooseff, M N
EM: mgooseff@engr.psu.edu
AF: Pennsylvania State University, Department of Civil & Environmental Engineering 212 Sackett Building, University Park, PA 16802, United States
AU: Goetz, R
EM: randy.goetz@gmail.com
AF: Utah State University, Department of Watershed Sciences 5210 Old Main, Logan, UT 84322-5210, United States
AU: Schmidt, J C
EM: jschmidt@cc.usu.edu
AF: Utah State University, Department of Watershed Sciences 5210 Old Main, Logan, UT 84322-5210, United States
AB: The Provo River Restoration Project has reconfigured 19-km of previously channelized and diked river length of the Provo River, Heber Valley, Utah. Reconfiguration has resulted in increased number and frequency of pool-riffle sequences and increasing river sinuosity. We expected that this increase in channel morphologic heterogeneity would result in enhanced transient storage of stream water due to 1) greater pool area that could accommodate enhanced in-channel dead zone storage, and 2) enhanced hyporheic exchange that would occur in response to greater hydraulic head variability throughout the reconfigured reaches. We measured channel geomorphology and estimated transient storage parameters in three reconfigured and three channelized river reaches to test our prediction. Transient storage parameters were estimated from simulations of Rhodamine-WT breakthrough curves in each of these six reaches using a 1-D solute transport model that accounts for transient storage. Despite substantial channel alterations, we found that estimates of mean residence time in storage, and mass transfer rates were not significantly different between reconfigured and channelized reaches. We did, however, find a significant increase (186%) in estimates of relative storage capacity (ratio of storage volume to main channel volume) in reconfigured reaches, compared to channelized reaches. Statistical correlation between geomorphic parameters and relative storage capacity suggests that reconfiguration may have resulted in increased in-channel storage in larger, more frequent reconstructed pools, and increased hyporheic exchange through shallow, rapidly exchanging flowpaths in steep reconstructed riffles. Thus reconstructed morphology did not yeild substantial increases in hyporheic exchange, as we had proposed. We observed substantial compaction of reconfigured channel beds during the construction process, suggesting that hyporheic exchange was likely limited by a shallow, low-permeability boundary.
DE: 1825 Geomorphology: fluvial (1625)
DE: 1830 Groundwater/surface water interaction
DE: 1856 River channels (0483, 0744)
DE: 1860 Streamflow
SC: Hydrology [H]
MN: 2007 Fall Meeting