U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September
20-24, 1993, Water-Resources Investigations Report 94-4015
  
Unsaturated Zone Transport at the Plains, Georgia Field Site
by
D.D. Bosch (U.S. Department of Agriculture, Agricultural Research
Service, Southeast Watershed Research Laboratory, Tifton, Georgia 31793),
R.A. Leonard (U.S. Department of Agriculture, Agricultural Research Service,
Southeast Watershed Research Laboratory, Tifton, Georgia 31793), and R.K.
Hubbard (U.S. Department of Agriculture, Agricultural Research Service,
Southeast Watershed Research Laboratory, Tifton, Georgia 31793)
Abstract
Soil-water and solute-transport data have been collected over
three years on a 0.81 ha field site located near Plains, Georgia.
Soil cores collected from the root and vadose zone show
extreme variability in movement and transport of applied bromide
(Br-) tracer. The Groundwater Loading Effects of Agricultural
Management Systems - Finite Element Solute Transport (GLEAMS-
FEST) root-vadose zone model was used to simulate Br-
transport below the site. Comparison of simulated concentrations
to horizontally averaged profile concentrations show
good agreement for year one but poor agreement thereafter, probably
due to inaccurate estimates of hydraulic parameters in deeper
parts of the vadose zone. Because of extreme variability in transport
data, profile-averaged concentrations may not be a
realistic representation of the sample data.
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