Test-Trench Studies in the Amargosa Desert, Southern Nevada--Results and Application of
Information to Landfill Covers in Arid Environments
Brian J. Andraski
Abstract
As arid sites in the western United States are increasingly sought for disposal of the
Nation's hazardous wastes and as volumes of locally generated wastes increase, concern about the
potential effect of contaminants on environmental quality is being raised. Studies at the U.S.
Geological Survey's Amargosa Desert research site near Beatty, Nevada are being done to
evaluate mechanisms that can affect waste isolation in an arid environment. Precipitation at the
site averages about 108 mm yr-1. Results have shown that, under undisturbed conditions, the
naturally stratified soils in combination with native plants are effective in limiting the potential
for percolation of precipitation. Under nonvegetated waste-site conditions, data indicated the
accumulation and shallow, but continued, penetration of infiltrated water. However, water
potentials below the test trenches and below the 2-m depth for nonvegetated soil indicated the
persistence of an upward driving force for water flow during the 5-yr test period. General trends
in trench-cover subsidence suggested a positive relation with cumulative precipitation, but
subsidence did not appear to have a measurable effect on the water balance. Erosion rates were
inversely related to near-surface rock-fragment content. Results suggest that the ultimate fate of
contaminants buried at properly managed solid-waste sites may be determined largely by the
interactions among climate and the surface-cover features of the disposal facility, and how these
factors change with time.
This abstract was presented at Landfill Capping in the Semi-
Arid West--Problems, Perspectives, and Solutions on May 21-22, 1997, and was
published in the proceedings.