HR: 1340h
AN: H33E-1433    [Abstracts]
TI: Scaling in Hydrologic Response and a Theoretical Basis for Derivation of Probabilistic Synthetic Unit Hydrographs
AU: * Shrestha, R K
EM: shres008@umn.edu
AF: St. Anthony Falls Laboratory and National Center for Earth-surface Dynamics, Department of Civil Engineering, University of Minnesota, Mississippi River @ 3rd Ave. SE, Minneapolis, MN 55414
AU: Zaliapin, I
EM: zal@ess.ucla.edu
AF: Institute of Geophysics and Planetary Physics and Department of Earth and Space Sciences, University of California, Los Angeles, 3845 Slichter Hall, Los Angeles, CA 90095
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, Mississippi River @ 3rd Ave. SE, Minneapolis, MN 55414
AB: Relating hydrograph characteristics (e.g. time to peak Tp, peak discharge Qp and flow-recession time Tb) to geomorphologic properties of a basin (e.g. drainage area, length of the mainstream, average catchment slope etc.) forms the basis of many empirical formulations for synthetic hydrographs (e.g. Snyder_fs formula, Kirpich formula etc.). In this study, we perform a rigorous scaling analysis of the probability distribution of Tp, Qp and Tb parameterized by drainage area for 31 basins of areas 10 - 10000 km2 in the midwestern US. These variables have been extracted from hourly discharge records using a multiscale trend analysis technique recently proposed by Zaliapin et al., (Fractals, 2004). For Tp, which is not influenced much by rainfall, we document the presence of two distinct mono-scaling regimes with a scaling break at a scale consistent with the transition in the fluvial regime from mostly erosional to mostly depositional, as proposed by Dodov and Foufoula-Georgiou (WRR, 2005). For small basins, the scaling exponent is close to 0.2 - 0.3 while for larger basins it is close to 0.4 - 0.5. The scaling of the other hydrograph characteristics is more complicated and needs renormalization with rainfall intensity and duration. Our results can be seen as providing a generalization of common empirical formulae for synthetic unit hydrograph estimation and can provide the basis for deriving regional and probabilistic synthetic hydrograph formulae based on rigorous scaling analysis which also allows incorporation of uncertainty (and even higher order moments) of the hydrograph properties.
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1839 Hydrologic scaling
DE: 1860 Streamflow
DE: 1869 Stochastic hydrology
DE: 1879 Watershed
SC: Hydrology [H]
MN: Fall Meeting 2005