HR: 0800h
AN: H31A-1285    [Abstracts]
TI: Shoreline response to autogenic processes of sediment storage and release in the fluvial system
AU: * Kim, W
EM: kimx0826@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-surface Dynamics, University of Minnesota, 2 Third Ave SE, Minneapolis, MN 55414 United States
AU: Paola, C
EM: cpaola@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-surface Dynamics, University of Minnesota, 2 Third Ave SE, Minneapolis, MN 55414 United States
AU: Swenson, J B
EM: jswenso2@d.umn.edu
AF: Department of Geological Sciences and Large Lakes Observatory, University of Minnesota Duluth, 1114 Kirby Drive, Duluth, MN 55812 United States
AU: Voller, V R
EM: volle001@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-surface Dynamics, University of Minnesota, 2 Third Ave SE, Minneapolis, MN 55414 United States
AB: We report results from an experimental study of a linked fluvial-shoreline-slope system to slow, rapid, and superimposed variation in base level. The experiment was carried out in the eXperimental EarthScape (XES) facility at St. Anthony Falls Laboratory. The experimental shoreline migration rate shows high-frequency autogenic variability superimposed on low-frequency allogenic shoreline responses. This variability persists even when the shoreline migration is averaged laterally. The autogenic signal in the shoreline migration rate is strongest during relative base-level rise and weakest during relative base-level fall. Base-level change, which is the only time-dependent boundary condition in the experiment, can work either for or against the sediment transport regime, and thus can magnify or diminish autogenic response. We used a 1-D geometric model to attempt to recreate the autogenic signals present in the experiment. In the model, we used periodic changes in the fluvial slope to represent the effects of storage and release of supplied sediment. This slope-change model generates periodic pulses of sediment discharge to the shoreline that can exceed by an order of magnitude the allogenic sediment discharge. The model captures at first order the high-frequency migrations in the observed shoreline data set against a background of relatively low- frequency migration rates.
UR: http://www.geo.umn.edu/orgs/seds
DE: 1815 Erosion
DE: 1825 Geomorphology: fluvial (1625)
DE: 1847 Modeling
DE: 1861 Sedimentation (4863)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: Fall Meeting 2005