HR: 09:15h
AN: H51H-06    [Abstracts]
TI: Scaling in River Corridor Widths Reflects the Signature of Valley Forming Processes
AU: * Gangodagamage, C
EM: gango009@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-Surface Dynamics, Department of Civil Engineering, University of Minnesota, 2, 3rd Avenue SE, Minneapolis, MN 55414, United States
AU: Foufoula-Georgiou, E
EM: efi@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-Surface Dynamics, Department of Civil Engineering, University of Minnesota, 2, 3rd Avenue SE, Minneapolis, MN 55414, United States
AB: In this paper, we analyze the statistical multiscaling structure of the "river corridor width" (RCW) series of a mountain stream in the Eel river basin, California, from the stream outlet (L= 0 m) to its basin divide (L =56 km) using 1m LIDAR digital elevation model (DEM). The RCW (defined the lateral distance from the centerline of the river to the left and right valley walls at a fixed height above the water surface) was extracted using a weighted cost algorithm in such a way that it delineated a modified DEM that shows the elevation of the river corridor geometry from a newly defined reference, the center line of the main stream. We flooded this DEM at different depths (D= 5m, 10m, 15m etc., up to 50 m) and the two interfaces of the flooded surface and river's right and left extended flood plains were extracted as a geophysical signal. We argue that the extracted signal carries the signature of valley forming processes (fluvial and hillslope processes and their interaction) that have been taking place at depth D above the water surface. These processes are in a transverse direction to the main stream and in a unit normal direction to the extracted signal. Fluvial processes that bring the sediment and debris flows at tributary junctions introduce a localized large-scale disturbance which superimposes on smaller- scale organization created by hillslope diffusion and land wasting processes such as landslides. To extract the embedded signatures of high frequency and low frequency fluctuations that superimpose in this geophysical signal and study its scaling properties, we use Wavelet Transform Modulus Maxima (WTMM) method. The results of this analysis provide a quantitative measure of landscape dissection at different river regimes and different scales and reveals important connections between the observed statistical structure of valley geometry and the physical processes responsible for its formation.
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1825 Geomorphology: fluvial (1625)
DE: 1826 Geomorphology: hillslope (1625)
DE: 1872 Time series analysis (3270, 4277, 4475)
DE: 3270 Time series analysis (1872, 4277, 4475)
SC: Hydrology [H]
MN: 2007 Joint Assembly