HR: 0800h
AN: H51E-0413 [Abstracts]
TI: Sediment Supply by Landsliding in a Steep Mountain Catchment
AU: * Densmore, A L
EM: densmore@erdw.ethz.ch
AF: ETH Zürich, Institute of Geology, Department of Earth Sciences, Zürich, CH-8092
Switzerland
AU: Schuerch, P
EM: peter@paddeln.ch
AF: ETH Zürich, Institute of Geology, Department of Earth Sciences, Zürich, CH-8092
Switzerland
AU: McArdell, B
EM: brian.mcardell@wsl.ch
AF: Swiss Federal Institute for Forest, Snow, and Landscape Research, Zürcherstrasse 111, Birmensdorf,
CH-8903
Switzerland
AU: Molnar, P
EM: molnar@ihw.baug.ethz.ch
AF: ETH Zürich, Institute of Hydromechanics and Water Resources Management, Zürich, CH-8093
Switzerland
AB:
We estimate rates of sediment supply by landsliding to an alluvial channel in a small catchment in central Switzerland over
an 11 month study period. Fluvial sediment transport in the channel is independently monitored at the upstream and downstream
ends of our study reach, yielding a unique opportunity to quantitatively compare the volume of sediment supplied to the
channel with the volume in transport. Landslide-derived sediment discharge to the channel is greatest during the winter and
spring months, while most of the fluvial sediment transport occurs during short, intense summer storms. Approximately 98
m3 of sediment are delivered to the channel by landsliding, ~80 m3 are transported into the reach, and ~70 m3
are transported out of the reach. Thus, there is a net accumulation of ~100 m3 of sediment during the 11 month study.
Longer-term channel aggradation and sediment storage are evident in surveys of the longitudinal profile from 1993 and 2004;
during this period, a total of ~1500 m3 of sediment accumulated in the study reach. Aggradation occurs largely in two
broad zones that correspond both with the locations of major landslide complexes and reaches of high channel slope,
indicating that hillslope sediment input leaves an imprint on the morphology of the channel bed that appears to be stable
over at least decadal time scales.
DE: 1826 Geomorphology: hillslope (1625)
DE: 1856 River channels (0483, 0744)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: Fall Meeting 2005