HR: 1330h
AN: H42D-1116    [PDF]
TI: Analysis of Spatial Soil Hydraulic Properties to Investigate Soil-Water Movement and Scaling in an Agricultural Field
AU: * Green, T R
EM: Tim.Green@ars.usda.gov
AF: USDA-ARS, GPSR P.O. Box E, Fort Collins, CO 80522 United States
AU: Erskine, R H
EM: Rob.Erskine@ars.usda.gov
AF: USDA-ARS, GPSR P.O. Box E, Fort Collins, CO 80522 United States
AU: Fogarty, E A
EM: Elizabeth.Fogarty@colostate.edu
AF: Colorado State University, Natural Resources Management, Fort Collins, CO 80523 United States
AU: Dunn, G H
EM: Gale.Dunn@ars.usda.gov
AF: USDA-ARS, GPSR P.O. Box E, Fort Collins, CO 80522 United States
AU: Salas, J D
EM: jsalas@engr.colostate.edu
AF: Colorado State University, Civil Engineering, Fort Collins, CO 80523 United States
AB: The coupled processes of overland flow, infiltration, and multidimensional soil-water flow and storage affect the space-time scaling behavior of measured soil-water content. Previous work on this farm field in eastern Colorado revealed simple scaling behavior in near-surface (0-30 cm) water content, despite generally poor correlation with landscape topographic attributes. In this study, we have analyzed soil hydraulic properties along a transect to help investigate coupled overland-subsurface flow processes and how the scaling behavior of measured and simulated soil-water content may be linked to such processes. Soil cores have been collected and analyzed for textural and hydraulic properties. Detailed analyses include three-step outflow experiments followed by numerical inverse simulations to estimate hydraulic conductivity and storage parameters. Spatial patterns of selected parameters and their correlations with topography will be illustrated. Hourly soil-water data has also been collected with capacitance probes at eight landscape positions and four depths along the undulating transect. The soil-water data suggests that significant lateral flow of soil water occurs at seasonal time scales, despite a lack of obvious impeding layers or perched groundwater. Overland flow also occurs during high-intensity rainfall events. Numerical simulation results of the coupled hydrologic processes may provide further insights into causative links with soil-water scaling.
DE: 1824 Geomorphology (1625)
DE: 1833 Hydroclimatology
DE: 1851 Plant ecology
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2003 Fall Meeting