HR: 0830h
AN: NG31A-0598    [PDF]
TI: PHYSICAL INSIGHTS INTO THE SCALING OF AT-SITE HYDRAULIC GEOMETRY AND SCALING OF FLOOD PEAKS
AU: * Dodov, B A
EM: dodo0001@tc.umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Mississippi River at 3rd Avenue SE, Minneapolis, MN 55414 United States
AU: Foufoula-Georgiou, E
EM: efi@tc.umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Mississippi River at 3rd Avenue SE, Minneapolis, MN 55414 United States
AB: The dependencies between channel properties and river flows known for a long time as at-station hydraulic geometry (HG: power laws connecting discharge to stream geometry) have been recently shown to systematically vary with scale (contributing area), and a model based on the multiscaling framework has been proposed to statistically describe this scale-dependence (Dodov and Foufoula Georgiou, AGU Fall meeting 2002). In this paper, we attempt to provide a physical explanation for the scale-dependence of at-station HG. Namely, we postulate that it arises from the scale-dependence of river sinuosity and, thus, channel cross-sectional asymmetry and we use observations and physical theories (channel stability analysis and linear theory of river meandering) to test this hypothesis. Also, physical insight to the multiscaling of flood peaks is offered. In particular, it is argued that the empirically observed break in variability of flood peaks with scale relates to the scale-dependent frequency of transition from below-bankfull to overbank flow, controlled by the systematic and interrelated variations of channel and flood plain geometries with contributing area.
DE: 1821 Floods
DE: 1824 Geomorphology (1625)
DE: 1860 Runoff and streamflow
DE: 3220 Nonlinear dynamics
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting