HR: 1340h
AN: H43F-1681    [Abstracts]
TI: Synthesis of Post-wildland Fire Sediment Yields in Different Rainfall Regimes in the western United States
AU: * Martin, D A
EM: damartin@usgs.gov
AF: U.S. Geological Survey, 3215 Marine Street Suite E127, Boulder, CO 80303-1066, United States
AU: Moody, J A
EM: jamoody@usgs.gov
AF: U.S. Geological Survey, 3215 Marine Street Suite E127, Boulder, CO 80303-1066, United States
AB: A variety of methods have been used to measure post-fire erosion across the western United States. We grouped these measurements into four methods: (1) point measurements on hillslopes, (2) hillslope plot measurements, (3) suspended-sediment and bed load sampling in channels, and (4) channel volume measurements of erosion or deposition. We classified features identified as "incised tributaries" or "gullies" as channel erosion. Only measurements made within two years of a fire were included in the synthesis. The measurement methods were stratified into seven different rainfall regimes based on seasonal rainfall type and rainfall intensities within each seasonal type. Post-wildfire sediment yields varied over five orders of magnitude for the different rainfall regimes. While differences in sediment yields exist across different rainfall regimes, a major source of variance is a result of the different methods used to measure post-fire erosion. A median sediment yield value for each measurement method was calculated. The average median sediment yield based on the channel volume method of 190 T/ha was greater than the sediment yields based on point measurements on hillslopes (29 T/ha), on hillslope plot measurements (14 T/ha), and on channel suspended-sediment and bed load sampling (2.5 T/ha) methods. This suggests that the channels are more important than the hillslope as sources of available sediment after wildfire. The lack of correlation of sediment yields with topographic slope and soil erodibility suggests that sediment availability may be more important than slope or erodibility in determining the sediment yield after wildfire
DE: 1815 Erosion
DE: 1833 Hydroclimatology
DE: 1856 River channels (0483, 0744)
DE: 1862 Sediment transport (4558)
DE: 1874 Ungaged basins
SC: Hydrology [H]
MN: 2007 Fall Meeting