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WATER RESOURCES RESEARCH, VOL. 38, NO. 12, 1291, doi:10.1029/2001WR000825, 2002

Deep arid system hydrodynamics 2. Application to paleohydrologic reconstruction using vadose zone profiles from the northern Mojave Desert

Michelle A. Walvoord

Earth and Environmental Science Department, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA


Fred M. Phillips

Earth and Environmental Science Department, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA


Scott W. Tyler

Department of Environmental and Resource Sciences and Department of Geological Sciences, University of Nevada, Reno, Nevada, USA


Peter C. Hartsough

Hydrologic Sciences Graduate Program, University of Nevada, Reno, Nevada, USA


Abstract

Site-specific numerical modeling of four sites in two arid alluvial basins within the Nevada Test Site employs a conceptual model of deep arid system hydrodynamics that includes vapor transport, the role of xeric vegetation, and long-term surface boundary transients. Surface boundary sequences, spanning 110 kyr, that best reproduce measured chloride concentration and matric potential profiles from four deep (230–460 m) boreholes concur with independent paleohydrologic and paleoecological records from the region. Simulations constrain a pluvial period associated with infiltration of 2–5 mm yr−1 at 14–13 ka and denote a shift linked to the establishment of desert vegetation at 13–9.5 ka. Retrodicted moisture flux histories inferred from modeling results differ significantly from those determined using the conventional chloride mass balance approach that assumes only downward advection. The modeling approach developed here represents a significant advance in the use of deep vadose zone profile data from arid regions to recover detailed paleohydrologic and current hydrologic information.

Published 17 December 2002.

Index Terms: 1866 Hydrology: Soil moisture; 1875 Hydrology: Unsaturated zone.

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Citation: Walvoord, M. A., F. M. Phillips, S. W. Tyler, and P. C. Hartsough (2002), Deep arid system hydrodynamics 2. Application to paleohydrologic reconstruction using vadose zone profiles from the northern Mojave Desert, Water Resour. Res., 38(12), 1291, doi:10.1029/2001WR000825.