Transient and steady-state solute transport through a large unsaturated soil column

Journal Article · · Ground Water; (United States)

DOI:https://doi.org/10.1111/j.1745-6584.1993.tb01811.x· OSTI ID:6504511

Porro, I ^[1]; Wierenga, P J ^[2]

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1. New Mexico State Univ., Las Cruces, NM (United States)
2. Univ. of Arizona, Tucson (United States)

The use of steady-state models can sometimes reduce the computational resources and input data required for solution of transient transport problems. A large column experiment was performed to test whether solute transport parameters determined from a steady flow experiment may be used in transient, unsaturated flow and transport model predictions. Tritiated water and bromide were applied at a steady rate to the top of a 0.95 m diameter by 6 m deep soil column containing unsaturated soil. After 10 days, tracers were eliminated from the irrigation water. When the soil moisture content within the column ceased to change, another 10-day pulse of tritiated water and bromide was applied, followed by water without tracers. Transport model parameters were determined through optimization, using breakthrough curves observed at various depths. The tritiated water and bromide pulses lagged behind the wetting front during infiltration into the relatively dry soil. The bromide pulse moved 17-20% faster than the tritiated water pulse, because of anion exclusion. Breakthrough curves for the transient and steady-state experiments were similar. Because the solute fonts lagged significantly behind the moisture fronts, steady-state transport parameters, when used in a fully transient numerical model, fairly described the transport under transient conditions.

• OSTI ID: 6504511
• Journal Information: Ground Water; (United States), Journal Name: Ground Water; (United States) Vol. 31:2; ISSN GRWAAP; ISSN 0017-467X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
BROMIDES
BROMINE COMPOUNDS
CHEMICAL WASTES
CONTAMINATION
ENVIRONMENTAL TRANSPORT
GROUND DISPOSAL
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MANAGEMENT
MASS TRANSFER
MATHEMATICAL MODELS
NONRADIOACTIVE WASTES
POLLUTION
SOILS
SOLUTES
STEADY-STATE CONDITIONS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER POLLUTION