HR: 0800h
AN: H51E-0415    [Abstracts]
TI: Sediment Budgets the 'Old Fashioned' way for two Subbasins of the Rio Puerco, Central New Mexico
AU: Pavich, M J
EM: mpavich@usgs.gov
AF: U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192
AU: * Gellis, A C
EM: agellis@usgs.gov
AF: U.S. Geological Survey, 8987 Yellow Brick Road, Baltimore, MD 21237
AU: Clark, I
EM: iclark@usgs.gov
AF: U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192
AU: Ellwein, A L
EM: ellwein@unm.edu
AF: University of New Mexico, 1 University of New Mexico, Albuquerque, NM 87131
AU: Aby, S
EM: nmaby@zianet.com
AF: Self employed, PO Box 488, Dixon, NM 87527
AB: A sediment budget was constructed for two subbasins of the Rio Puerco watershed, Volcano Hill Wash (9.30 km²) and Arroyo Chavez (2.28 km²), using data collected from 1995 through 1998. The subbasins were selected based on differences in land use. Arroyo Chavez was considered more degraded than Volcano Hill Wash, the latter of which received a grazing management award. The grazing density in the Arroyo Chavez watershed was higher (7.3 animals per 100 hectares) than in the Volcano Hill Wash watershed (1.0 animals per 100 hectares). A gas pipeline and numerous dirt roads are located within the Arroyo Chavez subbasin; neither are present within the Volcano Hill Wash subbasin. The 'old fashioned' sediment budget refers to the approach that was used--determining the total sediment leaving a basin and accounting for that sediment with a variety of field-based, labor intensive techniques. A sediment station with an automatic suspended-sediment sampler was installed at the mouth of each stream to quantify the amount of sediment leaving the subbasins. Upland erosion was measured using erosion pins and sediment traps. Channel erosion was measured using surveyed channel cross sections, bank pins, and scour chains. Aeolian dust deposition was measured with dust traps. Each subbasin was divided into geomorphic surfaces using aerial photographs and field descriptions of soils, slopes, and vegetation cover. In Volcano Hill Wash subbasin, five geomorphic surfaces were delineated: mesa, steep colluvial slopes, alluvium/ colluvium, eolian/alluvium, and the alluvial valley floor. In the Arroyo Chavez subbasin, seven geomorphic surfaces were delineated: mesa, steep colluvial slopes, moderate sloping hillslopes, gently sloping hillslopes, alluvial fans, well-vegetated alluvial valley floor, and a sparsely vegetated alluvial valley floor. Upland erosion and channel erosion rates were summed for each geomorphic surface using a geographical information system (GIS). Results indicate that in both subbasins the alluvial valley floor, where livestock graze, had the highest erosion rates. Sediment yields and erosion rates were higher in the degraded basin (Arroyo Chavez) and may indicate the effects of human land-use practices including higher density grazing, dirt roads, and pipeline activity.
DE: 1815 Erosion
DE: 1825 Geomorphology: fluvial (1625)
DE: 4558 Sediment transport (1862)
SC: Hydrology [H]
MN: Fall Meeting 2005