Description of borehole geophysical and geologist logs, Berks Sand Pit Superfund Site, Longswamp Township, Berks County, Pennsylvania

[摘要] Between October 2002 and January 2003, geophysical logging was conducted in six boreholes at theBerks Sand Pit Superfund Site, Longswamp Township, Berks County, Pa., to determine (1) the waterproducingzones, water-receiving zones, zones of vertical borehole flow, orientation of fractures, andborehole and casing depth; and (2) the hydraulic interconnection between the six boreholes and the siteextraction well. The boreholes range in depth from 61 to 270 feet. Geophysical logging included collectionof caliper, natural-gamma, single-point-resistance, fluid-temperature, fluid-flow, and acoustic-televiewerlogs. Caliper and acoustic-televiewer logs were used to locate fractures, joints, and weathered zones.Inflections on fluid-temperature and single-point-resistance logs indicated possible water-bearingfractures, and flowmeter measurements verified these locations. Single-point-resistance, natural-gamma,and geologist logs provided information on stratigraphy. Flowmeter measurements were conducted whilethe site extraction well was pumping and when it was inactive to determine the hydraulic connectionsbetween the extraction well and the boreholes.Borehole geophysical logging and heatpulse flowmetering indicate active flow in the boreholes. Twoof the boreholes are in ground-water discharge areas, two boreholes are in ground-water recharge areas,and one borehole is in an intermediate regime. Flow was not determined in one borehole. Heatpulseflowmetering, in conjunction with the geologist logs, indicates highly weathered zones in the graniticgneiss can be permeable and effective transmitters of water, confirming the presence of a two-tieredground-water-flow system.The effort to determine a hydraulic connection between the site extraction well and six loggedboreholes was not conclusive. Three boreholes showed decreases in depth to water after pumping of thesite extraction well; in two boreholes, the depth to water increased. One borehole was cased its entiredepth and was not revisited after it was logged by the caliper log. Substantial change in flow rates ordirection of borehole flow was not observed in any of the three wells logged with the heatpulse flowmeterwhen the site extraction well was pumping and when it was inactive.

[发布机构] U.S. Geological Survey

[学科分类] 地球科学(综合)