HR: 09:15h
AN: H41G-06    [Abstracts]
TI: Transported Sediment in Comparison with Channel Bed Material in Low-Order Alluvial Channels
AU: * Nichols, M
EM: mnichols@tucson.ars.ag.gov
AF: USDA ARS Southwest Watershed Research Center, 2000 E. Allen Rd, Tucson, AZ 85719 United States
AU: Canfield, E
EM: ecanfield@tucson.ars.ag.gov
AF: USDA ARS Southwest Watershed Research Center, 2000 E. Allen Rd, Tucson, AZ 85719 United States
AU: Yuill, B
EM: byuill@asu.edu
AF: Arizona State University, Dept of Geography, Tempe, AZ 85287 United States
AU: Schmeeckle, M
EM: schmeeckle@asu.edu
AF: Arizona State University, Dept of Geography, Tempe, AZ 85287 United States
AB: Sediment transported in alluvial channels consists of mobilized channel bed material combined with that detached from channel banks and sediment contributed through overland flow. Unconsolidated bed material provides an almost limitless sediment source. Although the particle distributions of the bed material and the transported sediment are often assumed to be the same, few dataset are available to test this assumption. Detailed measurements of channel geometry, bed material, and spatial patterns of coarse particle distribution were made on a low-order channel within the USDA-ARS Walnut Gulch Experimental Watershed. Sediment transported during the 2002 monsoon season was collected with a traversing slot sediment sampler and a pit trap. Particles size distributions of channel bed sediment are compared with the particle distributions of sediment collected during flash-flows. Initial results indicate that the bed material contains less fine sediment than the transported load, and sediment particles larger than 4 mm make up as much as 15% of the total sediment load transported during the measured events.
DE: 4558 Sediment transport
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting