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 Properties at a Hazardous-Waste-Disposal Site
at the Idaho National Engineering Laboratory
by
Stephanie Shakofsky (U.S. Geological Survey, Menlo Park, Calif.)
and John R. Nimmo (U.S. Geological Survey, Menlo Park, Calif.)
Abstract
Field and laboratory investigations at a hazardous-waste site at the
Idaho National Engineering Laboratory (INEL) have yielded measurements of
the hydraulic properties that govern water and contaminant transport in
the unsaturated zone. Saturated and unsaturated vertical hydraulic conductivity,
soil-moisture retention, porosity, and particle-size distribution were measured
in core samples collected from depths of 18 to 245 cm. In addition,
the degree of soil aggregation and relative carbonate content with depth
were analyzed in the field. In order to assess the effect of the disposal
trenches and pits on hydrologic transport-governing properties, studies
were made of (1) a simulated waste trench that was constructed as a model
of the waste-containing trenches, and (2) a nearby undisturbed soil profile.
Results show that the undisturbed soil profile has distinct layers whose
properties differ significantly, whereas the soil profile in the simulated
waste trench is, to a large degree, homogeneous. In general, the vertical
movement of water is expected to be retarded in a distinctly layered medium,
suggesting that the construction of trenches and pits has destroyed some
natural impediments to downward flow.
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