Evaluation of borehole geophysical and video logs, at Butz Landfill Superfund Site, Jackson Township, Monroe County, Pennsylvania

Abstract

Between February 1996 and November 2000, geophysical logging was conducted in 27 openborehole wells in and adjacent to the Butz Landfill Superfund Site, Jackson Township, Monroe County, Pa., to determine casing depth and depths of water-producing zones, water-receiving zones, and zones of vertical borehole flow. The wells range in depth from 57 to 319 feet below land surface. The geophysical logging determined the placement of well screens and packers, which allow monitoring and sampling of water-bearing zones in the fractured bedrock so that the horizontal and vertical distribution of contaminated ground water migrating from known sources could be determined. Geophysical logging included collection of caliper, natural-gamma, single-point-resistance, fluid-resistivity, fluid-temperature, and video logs. Caliper and video logs were used to locate fractures, joints, and weathered zones. Inflections on single-point-resistance, fluid-temperature, and fluid-resistivity logs indicated possible water-bearing fractures, and heatpulse-flowmeter measurements verified these locations. Natural-gamma logs provided information on stratigraphy. INTRODUCTION The Butz Landfill Superfund Site (Butz Landfill) covers approximately 13.4 acres; the landfill area and monitor wells are shown on the U.S. Geological Survey (USGS) Mount Pocono 7.5-minute topographic quadrangle map (fig. 1). The Butz Landfill was used as a municipal-waste dump from approximately 1963 until at least 1969; some landfill activities probably continued until 1984 (Bureau of Reclamation, 1994). In early 1973, the Pennsylvania Department of Environmental Protection (PADEP) ordered the landfill closed. In 1986, PADEP conducted a site inspection and sampling program of domestic wells in close proximity to the site and detected volatile organic compounds (VOC’s) in the ground water. A Remedial Investigation/Feasibility Study (RI/FS) was initiated by the U.S. Environmental Protection Agency (USEPA) and its consultants in December 1988 and completed in September 1991. The RI/FS identified trichloroethylene (TCE), 1,2-dichloroethene (1,2-DCE), and vinyl chloride (VC) as the principal contaminants. In June 1992, the Record of Decision (ROD) was signed stating that no remedial actions were necessary for surface water, sediments, or the landfill. The selected remedy for contaminated ground water was to design and install a well-extraction system that would reduce TCE concentrations to background levels prior to discharge to local surface waters. On the basis of the remedial actions in the ROD, USEPA requested the Bureau of Reclamation (BOR) to install a permanent water-supply system and design and install an extraction-well system for cleanup of contaminated ground water. In 1996, BOR asked USGS to assist with hydrologic investigations for the Remedial Design (RD) study at the Butz Landfill. USGS involvement was directed toward identification of water-bearing zones in the contaminated fractured-bedrock aquifer to help ensure monitor wells were completed at appropriate depth horizons. This work is part of the support provided by USGS to USEPA on hydrogeologic investigations at Superfund sites in Pennsylvania.