Twenty-one wells were drilled at Crossley Farms Superfund Site between December 15, 1987,
and May 1, 1988, to define and monitor the horizontal and vertical distribution of ground-water
contamination emanating from a suspected contaminant source area (Blackhead Hill). Eight well
clusters were drilled on or near the Crossley Site and three well clusters were drilled at locations
hydrologically down gradient from the site. Depths of wells range from 21 to 299 feet below land
surface. These wells were installed in saprolite in shallow, intermediate, and deep water-producing
zones of the fractured bedrock aquifer.
Borehole-geophysical and video logging were conducted between April 24, 1997, and May 8, 1997,
to determine the water-producing zones, water-receiving zones, zones of vertical flow, borehole
depth, and casing integrity in each well. This data and interpretation will be used to determine the
location of the well intake for the existing open-hole wells, which will be retrofitted to isolate and
monitor water-producing zones and prevent further cross-contamination within each open borehole,
and identify wells that may need rehabilitation or replacement.
Caliper and video logs were used to locate fractures, inflections on fluid-temperature and fluidresistivity
logs indicated possible fluid-bearing fractures, and flowmeter measurements verified
these locations. Single-point-resistance and natural-gamma logs provided information on
stratigraphy. After interpretation of geophysical logs, video logs, and driller?s notes, all wells will be
constructed so that water-level fluctuations can be monitored and discrete water samples collected
from shallow, intermediate, and deep water-bearing zones in each well.
Geophysical logs were run on seven bedrock and two deep bedrock wells. Gamma logs were run
on 10 bedrock wells. Twenty-two wells were inspected visually with the borehole video camera for
Additional publication details
USGS Numbered Series
Evaluation of geophysical logs, phase I, for Crossley Farms Superfund Site, Berks County, Pennsylvania