Characterization of Fractures and Flow Zones in a
Contaminated Shale at the Watervliet Arsenal,
Albany County, New York
by John H. Williams and Frederick L. Paillet
U.S. GEOLOGICAL SURVEY
Open-File Report 01-385
ABSTRACT
Flow zones in a fractured shale in and near a
plume of volatile organic compounds at the
Watervliet Arsenal in Albany County, N. Y. were
characterized through the integrated analysis of
geophysical logs and single- and cross-hole flow
tests. Information on the fracture-flow network at
the site was needed to design an effective groundwater
monitoring system, estimate offsite
contaminant migration, and evaluate potential
containment and remedial actions.
Four newly drilled coreholes and four older
monitoring wells were logged and tested to define
the distribution and orientation of fractures that
intersected a combined total of 500 feet of open
hole. Analysis of borehole-wall image logs
obtained with acoustic and optical televiewers
indicated 79 subhorizontal to steeply dipping
fractures with a wide range of dip directions.
Analysis of fluid resistivity, temperature, and
heat-pulse and electromagnetic flowmeter logs
obtained under ambient and short-term stressed
conditions identified 14 flow zones, which consist
of one to several fractures and whose estimated
transmissivity values range from 0.1 to more than
250 feet squared per day.
Cross-hole flow tests, which were used to
characterize the hydraulic connection between
fracture-flow zones intersected by the boreholes,
entailed (1) injection into or extraction from
boreholes that penetrated a single fracture-flow
zone or whose zones were isolated by an
inflatable packer, and (2) measurement of the
transient response of water levels and flow in
surrounding boreholes. Results indicate a well
connected fracture network with an estimated
transmissivity of 80 to 250 feet squared per day
that extends for at least 200 feet across the site.
This interconnected fracture-flow network greatly
affects the hydrology of the site and has important
implications for contaminant monitoring and
remedial actions.
Citation: Williams, J.H. and Paillet, F.L., 2001,
Characterization of fractures and flow zones in a
contaminated shale at the Watervliet Arsenal,
Albany County, New York:
U.S. Geological Survey Open-File Report 01-385, 25 p.
[Full Report, Acrobat PDF
(2.1M)]
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