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MOBILIZATION AND TRANSPORT OF SOIL PARTICLES DURING INFILTRATION EXPERIMENTS IN AN AGRICULTURAL FIELD, SHENANDOAH VALLEY, VIRGINIA. (R824772)
Citation:
El-Farhan, Y. H., N. M. DeNovio, J. S. Herman, AND G. M. Hornberger. MOBILIZATION AND TRANSPORT OF SOIL PARTICLES DURING INFILTRATION EXPERIMENTS IN AN AGRICULTURAL FIELD, SHENANDOAH VALLEY, VIRGINIA. (R824772). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 34:3555-3559, (2000).
Description:
Evidence that fine particles mobilized and transported in
soils and aquifers can have a profound influence on
contaminant migration has spawned much interest recently
in understanding colloid transport in natural materials.
Repeated infiltration experiments on an initially dry field
soil were conducted to evaluate rates of mobilization of fine
particles over time and to investigate the importance of
transient-flow events on particle transport. Water flow was
measured in zero-tension lysimeters at 25 cm depth. For
repeated infiltration events and for all plots, water flow sharply
increased shortly after initial ponding of water at the
soil surface, maintained a relatively steady level during
the period of ponding, and decreased gradually thereafter.
Particle concentrations measured in the pan lysimeters
ranged from 7 mg L-1 to 265 mg L-1 and were typically on
the order of 10 to 100 mg L-1. Greatest particle mass
flux was observed during the initial infiltration experiment
on each plot. During four subsequent infiltration experiments,
all conducted within 250 min of the first event, steady mass
fluxes were observed that were approximately 70% of
the average value seen in the first flush of water through
a dry soil, indicating that the supply of mobile soil
particles is only sparingly reduced over closely spaced
infiltration events. All peak particle concentrations and mass
fluxes occurred near either the rising limb or the falling
limb of the water flux hydrograph, presumably reflecting the
movement of air-water interfaces during imbibition and
drainage.