HR: 0800h
AN: H41C-0417    [Abstracts]
TI: A Multi-faceted Investigation of the Effects of Wildfire on a Southern California Watershed
AU: * Kong, H
EM: kongh@seas.ucla.edu
AF: University of California, Los Angeles, Dept. of Civil and Environmental Engineering, 5732 Boelter Hall, Los Angeles, CA 90095-1593
AU: Morrissey, S
EM: skmbruin@excite.com
AF: University of California, Santa Barbara, Dept. of Geological Sciences, Santa Barbara, CA 93106
AU: Hogue, T
EM: thogue@seas.ucla.edu
AF: University of California, Los Angeles, Dept. of Civil and Environmental Engineering, 5732 Boelter Hall, Los Angeles, CA 90095-1593
AU: Rademacher, L
EM: lrademacher@pacific.edu
AF: University of the Pacific, Dept. of Geosciences, 3601 Pacific Avenue, Stockton, CA 95211
AU: Meixner, T
EM: tmeixner@hwr.arizona.edu
AF: University of Arizona, Dept. of Hydrology and Water Resources, Harshbarger Bldg. 11, Tucson, AZ 85721
AB: Wildfires and their hydrologic consequences pose serious hazards across the western United States. Post-fire flash flooding and debris flows are destructive to property and cost the lives of downstream populations. Field studies, geochemical analyses, and hydrologic modeling were used to investigate the hydrologic response following fire in the San Bernardino Mountains in Southern California. Field studies show the development of a hydrophobic layer which increased the overland flow component in the burned City Creek watershed. The runoff ratio increased by 130 percent when compared to the previous four years of runoff. An end-member mixing analyses (EMMA) for post-fire City Creek and an unburned control watershed (Mill Creek) was developed. Stream water samples from the burned watershed indicate components more similar to the precipitation end member, whereas samples from the unburned watershed are more similar to the groundwater member. Samples from the burned watershed also contain less of the soil water component than the unburned samples. Stable isotopes were also used to develop a two component hydrograph separation for post-fire streamflow. This method indicates increased overland flow directly after the fires, with this component decreasing over time. The National Weather Service Sacramento Soil Moisture Accounting Model (SAC-SMA), used for operational forecasting in the United States, was calibrated to both pre- and post-fire streamflows. Post-fire model simulations (with calibration) showed a significant decrease in performance when compared to pre-fire simulations.
DE: 1846 Model calibration (3333)
DE: 1850 Overland flow
DE: 1860 Streamflow
DE: 1879 Watershed
SC: Hydrology [H]
MN: Fall Meeting 2005