Wednesday, June 6, 2007 - 4:15 PM

Effects of Channel Reconfiguration on Transient Storage Dynamics in the Provo River, Utah

Michael Gooseff1, Jack C. Schmidt2, and Randy Goetz2. (1) Department of Geology and Geological Engineering, Colorado School of Mines, 1516 Illinois St., Golden, CO 80401, (2) Department of Watershed Sciences, Utah State University, 5210 Old Main, Logan, UT 84322

The Provo River Restoration Project has reconfigured 19-km of the Provo River, Heber Valley, Utah. Channel geomorphology was measured and transient storage parameters estimated in three reconfigured and three channelized stream reaches to determine the relative effects of channel reconfiguration on reach-integrated transient storage, a process important to restoring stream ecosystem function. Transient storage parameters were estimated from simulations of Rhodamine-WT breakthrough curves in each of these six reaches using a numerical solution to a modified one-dimensional advection-dispersion equation. Despite substantial channel alterations, we found that estimates of solute residence time in storage, and mass transfer rates were not significantly different between reconfigured and channelized reaches. However, there was a significant increase (186%) in estimates of relative storage capacity. 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, quickly exchanging flowpaths in steep reconstructed riffles. Thus reconstructed morphology and substrate are found to be important controls on transient storage characterisitics.