HR: 0800h
AN: H51B-0463    [Abstracts]
TI: Processes Controlling Stream Flow Chemistry in Semiarid, Forested Catchments, Valles Caldera, New Mexico
AU: * Liu, F
EM: fliu@ucmerced.edu
AF: University of California, Merced, School of Engineering, Merced, CA 95343, United States
AU: Parmenter, B R
EM: bparmenter@vallescaldera.gov
AF: Valles Caldera National Preserve, P.O. Box 359, Jemez Springs, NM 87025, United States
AU: Brooks, P D
EM: brooks@hwr.arizona.edu
AF: University of Arizona, Department of Hydrology and Water Resources, Tucson, AZ 85721, United States
AU: Conklin, M H
EM: mconklin@ucmerced.edu
AF: University of California, Merced, School of Engineering, Merced, CA 95343, United States
AU: Bales, R C
EM: rbales@ucmerced.edu
AF: University of California, Merced, School of Engineering, Merced, CA 95343, United States
AB: Using mixing models and point and spatially distributed snow data, controls of stream flow chemistry from headwaters to higher order streams at the East Fork of the Jemez River were identified. The East Fork of the Jemez River, located in Valles Caldera in New Mexico, drains a total area of 1400 km² and is primarily characterized by highly fractured tuff. Chemical data were collected from 2005 to 2007 from tributaries of the East Fork of Jemez River. Remotely sensed snow-covered area (SCA) data from MODIS were also used to determine snowmelt timing, estimate snowmelt quantity and help understand stream flow generation in these ungaged catchments. A new modeling procedure was developed to identify conservative chemical tracers and end-members contributing to stream flow using diagnostic tools of mixing models and end-member mixing analysis. Results indicate that stream flow chemistry is primarily controlled by mixing of shallow subsurface flow and groundwater (overland flow and in-stream chemical reactions are not important). From smaller to larger catchments, the number of end-members does not change, but chemical compositions of those end-members change with catchment size, slope and snow water equivalent. This new modeling tool set may be used elsewhere to examine processes controlling stream flow chemistry and the changes of stream flow chemistry with catchment characteristics.
DE: 1806 Chemistry of fresh water
DE: 1831 Groundwater quality
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2007 Fall Meeting