Indiana
Jefferson
Proving
Ground
40-Acre Site
Figure 1. Location of the 40-acre site at Jefferson Proving Ground.
limestone bedrock interface where small rock fragments
predominantly sedge and grass with a few trees. The area
occur. The bedrock ranges from about 1.5 to 7.6 m deep.
has a nearly level to gently sloping topography with small
The soils are part of either the Cobbsfork-Avonburg
gullies providing only a few meters of relief. The site has
(CA) or Cincinnati-Rossmoyne-Hickory (CRH) soil
been specially prepared with approximately 246 unfused,
map units. The CA soils are found on level to gently
buried ordnance and 234 nonordnance targets buried
sloping surfaces, are generally poorly drained, and have
within 1 m of the surface. The ordnance includes small,
a seasonally high water table. They can also have a pan
handheld munitions, 2-ft- (0.6-m-) long projectiles, and
layer, which can create a perched water table at a depth
5-ft- (1.6-m-) long bombs. Strong radio background noise
of 0.31 m for a significant part of the year. The CRH
was present at this site.
soils are found on level to steep surfaces and are classed
We conducted our surveys from 23 to 25 October
as well drained to moderately well drained. They may
1997. The weather was clear on 23 October, and then
light rain fell late on the 24th and all day on 25 Octo-
also have a pan layer of low permeability and perched
ber. All of our profile transects were freshly mowed,
water tables at depths of 0.51 m during the winter and
but clumps of woody vegetation and tractor ruts made
spring. In general, both soil units have a 15- to 20-cm
for uneven antenna towing and short periods of poor
surface soil consisting of silt loam varying from dark
antennaground contact.
brown to gray brown. The permeability tends to
decrease with depth because of an increase in clay con-
tent in the pan layers.
SOILS
X-ray diffraction studies performed by the U.S.
Army Waterways Experiment Station in Vicksburg,
The soils in this area formed in a thin surface layer
Mississippi, show the soil mineralogy to be primarily
of windblown silt (loess) and underlying glacial drift
quartz and plagioclase feldspar with clay minerals gen-
(Nickell 1985). Some residual soils may reside near the
erally absent or in minor amounts. This is consistent
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