HR: 1340h
AN: H23E-1179    [Abstracts]
TI: A New View of Amazon Floodplain Inundation Hydraulics
AU: * Alsdorf, D
EM: alsdorf@geology.ohio-state.edu
AF: Dept. of Geological Sciences, The Ohio State University, Columbus, OH 43210 United States
AB: Community based efforts are underway to propose a satellite mission for measuring surface water hydraulics. Such a mission is essential for advancing our hydrologic view from 1D point-based gauge measurements of discharge to 2D measurements of surface water that capture the complex spatial dynamics of flow (e.g., measurements of elevations, h, and their change, dh/dt and dh/dx). Examples are essential for demonstrating the utility of such measurements for improving our understanding of the mass-balances in the global water cycle and of the dynamics of complex floodplain hydraulics. Interferometric SAR yields high-spatial resolution images of dh/dt, albeit with a dt greater than desired and the method only permits measurements from inundated vegetation (it fails for open-water). Nevertheless, new observations from interferometric JERS-1 data during inundation over the central Amazon floodplain show dh/dt changes marking flow corridors of several kilometers width that are particularly apparent for the Cabaliana region. Many floodplain channels are conspicuous because dh/dt changes are not equivalent on both sides suggesting that flow delivery and decantation to surrounding floodplain areas is uneven. In fact, for some floodplain channels, dh/dt is greatest on the upstream side of the adjacent main channel (e.g., the Solimoes, Purus Rivers) during inundation but at peak stage, water delivery from the Amazon dominates resulting in a greater dh/dt on the downstream side of these floodplain channels. During early rising water, inundation appears first as a patchwork bordered by small floodplain channels, whereas at mainstem peak stage, floodplain flow appears to sub-parallel the mainstem. Essentially, the hydraulics of Amazon floodplain inundation are a complex interaction of local geomorphology and water stage. These views are only apparent from a spaceborne platform, yet are key for improving our understanding of floods and their transported biogeochemical and sediment constituents.
DE: 1821 Floods
DE: 1860 Runoff and streamflow
DE: 1890 Wetlands
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting