HR: 0800h
AN: H51E-0820    [Abstracts]
TI: Channel Morphological Changes in the Yuba River, California, in the Post-Hydraulic Mining Period
AU: * Ghoshal, S
EM: SubhajitGhoshal@gmail.com
AF: University of South Carolina, Geography Department 709 Bull Street, Columbia, SC 29208, United States
AU: James, A
EM: AJames@sc.edu
AF: University of South Carolina, Geography Department 709 Bull Street, Columbia, SC 29208, United States
AU: Singer, M
EM: bliss@bren.ucsb.edu
AF: University of California, Institute for Computational Earth Systems Science, Santa Barbara, CA 93106, United States
AU: Aalto, R
EM: Rolf.aalto@exeter.ac.uk
AF: University of Exeter, Department of Geography, Exeter, EX4 4RJ, United Kingdom
AB: Hydraulic gold mining in the Sierra Nevada of California (1853-1884) produced large volumes of sediment from upland placer gravels. The prevailing belief has been that piedmont storage of this sediment is volumetrically negligible or inactive. This study tests the hypothesis that large deposits of historical sediment remaining in the bed, banks and terraces of the lower Yuba River have been remobilized by floods and that erosion has continued over the past few decades. Remote sensing and GIS analyses of topographic and planimetric data from historical maps, surveys, aerial photographs, and LiDAR data document historic changes and the timing of sediment erosion and deposition within the channel and floodplain system. Planimetric and volumetric measurements of channel enlargement, lateral migration, avulsions, and channel filling provide magnitudes of erosion and deposition of historic sediments in the lower Yuba River. In 1906, the California Debris Commission produced a detailed large-scale topographic map of the lower Yuba floodplain showing it as a multi-thread channel system. The paleochannel scars remain evident on air photos, LiDAR images, and in the field. Differencing of topographic data derived from the 1906 topographic maps and 1999 LiDAR data provide volumetric measures of substantial channel morphologic changes including channel shifting, filling, and evolution towards a single- thread channel system. These measures identify processes and rates of sediment production relevant to broader issues of flood hazards in the region.
UR: http://people.cas.sc.edu/ajames/sacvalley.data/
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1640 Remote sensing (1855)
DE: 1825 Geomorphology: fluvial (1625)
DE: 1855 Remote sensing (1640)
DE: 1856 River channels (0483, 0744)
SC: Hydrology [H]
MN: 2007 Fall Meeting