HR: 13:55h
AN: H43I-02    [Abstracts]
TI: Patterns and Processes in Southwestern shrublands and grasslands: role of vegetation, soil- geomorphology, and overland flow
AU: * Bedford, D R
EM: dbedford@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd MS973, Menlo Park, CA 94025, United States
AU: * Bedford, D R
EM: dbedford@usgs.gov
AF: Department of Geological Sciences University of Colorado Boulder, 2200 Colorado Ave Box 399, Boulder, CO 80309-0399, United States
AU: Small, E E
EM: eric.small@colorado.edu
AF: Department of Geological Sciences University of Colorado Boulder, 2200 Colorado Ave Box 399, Boulder, CO 80309-0399, United States
AU: E, T G
EM: gtucker@cires.colorado.edu
AF: Department of Geological Sciences University of Colorado Boulder, 2200 Colorado Ave Box 399, Boulder, CO 80309-0399, United States
AB: Pattern of variable soil properties have been linked to vegetation as well as soil-landform characteristics and processes. It has been long hypothesized that patterns of infiltration and overland flow play key roles in arid and semi-arid region ecohydrology. Specifically, the process of redistribution of water and sediments have been linked to vegetation related feedbacks that enable persistence of vegetation in water limited environments. Yet, the processes of redistribution, such as through runoff and surface ponding, have been poorly described or documented. We have documented that the spatial pattern of soil properties is dependant on the vegetation pattern as well as the type of, and in some cases location within a, landform. These patterns are likely due to feedbacks between vegetation and the surface processes that affect soil properties and therefore water availability. In this paper, we present observations and numerical simulation that show how patterns of overland flow and infiltration are affected by vegetation-topography related patterns of soil properties. We have developed a numerical model that works on 10 cm grid cells that can inform on the processes of infiltration and overland flow over continuously varying soil properties. We use this model to show how the patterns of soil properties affect runoff, as well as the conditions under which redistribution via runon and ponding can occur. Furthermore, we show using data from a central New Mexico grassland and shrubland, and an eastern Mojave Desert shrubland how climatic differences can affect the patterns of infiltration and runoff.
DE: 1813 Eco-hydrology
DE: 1826 Geomorphology: hillslope (1625)
DE: 1838 Infiltration
DE: 1850 Overland flow
DE: 1865 Soils (0486)
SC: Hydrology [H]
MN: 2007 Fall Meeting