HR: 1330h
AN: H32A-0545    [PDF]
TI: Characterization of Soil Moisture Variability Along a Hillslope in a Semiarid Catchment, Dry Creek Watershed, Boise, Idaho
AU: * Williams, C J
EM: Christopherwilliams1@mail.boisestate.edu
AF: Boise State University, Department of Geosciences 1910 University Drive, Boise, ID 83725 United States
AU: McNamara, J P
EM: jmcnamar@boisestate.edu
AF: Boise State University, Department of Geosciences 1910 University Drive, Boise, ID 83725 United States
AU: Chandler, D G
EM: dchandle@mendel.usu.edu
AF: Utah State University, Department of Plants, Soils, and Biometeorology 4800 Old Main Hill, Logan, UT 84322 United States
AB: The spatial and temporal distribution of soil moisture exerts significant control on hillslope hydrologic processes. Recent research has identified the need for soil moisture data collection at the point scale to assist calibration and validation of remote sensing data, to facilitate understanding of soil water fluxes, and for modeling of hillslope hydrologic processes. The objectives of this research were to describe the temporal and spatial distribution of soil moisture in a 0.02 square kilometer semiarid catchment in the headwaters of the Dry Creek basin near Boise, Idaho, and to collect soil water content data to assist the calibration and validation of a shallow soil hydrologic model for forecasting streamflow initiation and hillslope hydrologic processes along the Boise Front, Boise, Idaho. Additionally, the results of the study may be applied to the investigation of shrub encroachment in shrub-grass ecotones along the Boise Front relative to changes in soil moisture. Near-surface soil moisture data was collected using time domain reflectometry (TDR) along a 10 x 20 meter grid in a 0.02 square kilometer catchment (Upper Dry Creek study area) in the Boise Foothills. Results suggest that slope position and shape are the dominant topographic influences on soil moisture at the Upper Dry Creek site. Upper slopes were well drained, and middle to lower slopes represented a convergence of lateral subsurface flow. Soil moisture content on concave and convex slopes was greatest in the middle and lower elevations following snowmelt and in the upper and lower elevations during drydown. Results indicate that lateral unsaturated subsurface flow on steep concave and convex slopes (non-local control) is the mechanism for the distribution of soil moisture in the Upper Dry Creek study area during snowmelt.
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2003 Fall Meeting