HR: 1340h
AN: H13D-0458    [Abstracts]
TI: Steady-State Upward Flow Through Layered Soils Under Shallow Water Table Conditions
AU: * Martinez, C J
EM: chrisjm@ufl.edu
AF: Department of Environmental Engineering Sciences University of Florida, P.O. Box 116450, Gainesville, FL 32611 United States
AU: Annable, M D
AF: Department of Environmental Engineering Sciences University of Florida, P.O. Box 116450, Gainesville, FL 32611 United States
AU: Jawitz, J W
AF: Soil and Water Science Department University of Florida, P.O. Box 110510, Gainesville, FL 32611 United States
AU: Campbell, K L
AF: Department of Agricultural and Biological Engineering University of Florida, P.O. Box 110570, Gainesville, FL 32611 United States
AB: The maximum steady state upward movement of water from a shallow water table in response to evaporation is of interest to crop water supply, water budgeting, and the estimation of evapotranspiration. In practice, soil profiles are often assumed to be homogenous to simplify calculations. Under certain conditions this assumption can lead to serious error in determining the connectivity between the shallow water table and the evaporating surface. Herein we investigate the conditions under which the steady state upward movement of water through a two-layered soil profile deviates from that of a homogenous soil. The effect of layering sequence, layer thickness, and similarity of layer hydraulic properties are addressed. Under shallow water table depths the rate of upward water movement decreased below that of both homogenous soils as the thickness of the top coarse layer decreased for a soil profile composed of a fine layer overlain by a coarse layer. In contrast the rate of upward water movement increased above that of both homogenous soils under shallow water table depths for the alternate case of a fine soil on top of coarse soil as the top fine layer thickness decreased. Under deep water table conditions the upward flow approached that of the homogenous coarse soil for both layering sequences. At these deeper water table depths the case of the coarse soil over the fine soil approached that of the homogenous coarse soil much more rapidly than the case of the fine soil on top of the coarse.
DE: 1818 Evapotranspiration
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting