HR: 1340h
AN: H43C-0506    [Abstracts]
TI: Investigating the Hydraulic Geometry of Floodplains Using a Hydrogeomorphic Delineation Method
AU: * Nardi, F
EM: fernando.nardi@uniroma1.it
AF: University of Rome La Sapienza, Via Eudossiana, 18 , Rome, 00184 Italy
AU: Vivoni, E R
EM: vivoni@nmt.edu
AF: New Mexico Institute of Mining and Technology, 801 Leroy Place , Socorro, NM 87801 United States
AU: Grimaldi, S
EM: salvatore.grimaldi@irpi.cnr.it
AF: Research Institute for Geo-hydrological Protection, National Research Council, Via Madonna Alta, 126, Perugia, 06128 Italy
AB: Large floods leave a clear trace on fluvial valleys, leading to distinct hydrogeomorphic, biogeochemical and ecologic properties in floodplain areas with respect to surrounding regions. Floodplain topography intrinsically contains information on the hydrogeomorphic signature of past erosional and depositional processes. As a result, high resolution, digital elevation models (DEMs) should be a valuable tool for characterizing floodplain extent and distinguishing processes occurring within and outside fluvial valleys. In this study, we propose a hydrogeomorphic, variable-level floodplain delineation method which links a simplified inundation algorithm with the hydrologic and geomorphic properties of the river basin. By working at the river basin scale, the method is capable of extracting valley bottom features throughout the channel network for a flood event of a particular magnitude. The method is utilized to investigate the physical controls on floodplain formation, as captured by scaling relations between floodplain geometry (e.g., flood stage and width) and contributing area at the channel cross section. Our hypothesis is that an efficient floodplain delineation grounded in hydrogeomorphic theory can improve our understanding of floodplain geometry and permit systematic tests of a floodplain scaling relation across a range of conditions. Several tests are performed on study areas with different climate conditions to validate the proposed floodplain extraction method as compared to other delineation approaches. We find that the floodplain geometry scaling relation exists across different climate regimes. Furthermore, we test the sensitivity and performance of the hydrogeomorphic method in relation to the DEM resolution. While fairly simple, this approach is theoretically sound, readily implemented in a geographic information system (GIS) and useful for further systematic tests of floodplain scaling properties.
DE: 1819 Geographic Information Systems (GIS)
DE: 1820 Floodplain dynamics
DE: 1821 Floods
DE: 1825 Geomorphology: fluvial (1625)
DE: 1839 Hydrologic scaling
SC: Hydrology [H]
MN: Fall Meeting 2005