Review of Aquifer Test Results for the Lansdale Area, Montgomery County, Pennsylvania, 1980–95

Open-File Report 98-294
Prepared in cooperation with the U.S. Environmental Protection Agency
By:  and 

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Abstract

Aquifer and aquifer-isolation test results in and around North Penn Area 6 Superfund site, Lansdale, Montgomery County, Pennsylvania are reviewed to provide estimated aquifer properties for use in a numerical model of ground-water flow. This review was made to support of remedial action investigations by U.S. Environmental Protection Agency (USEPA), Region III, Philadelphia. The data reviewed are from files of the U.S. Geological Survey, USEPA, and water companies, and from unpublished consultant reports prepared for USEPA and corporations in the Lansdale area. Tested wells are in fractured sedimentary rocks of the Brunswick Formation, which are Triassic-aged, dipping shales and sandstones. Review procedures include, in some cases, new analyses of drawdown during pumping and recovery by use of analytical models of flow to wells. Estimated aquifer transmissivities (T) range from zero to about 1,300 m2/d (meters squared per day); most tests indicate T between 10 and 100 m2/d. Aquifer-isolation testing results indicate that most flow enters wells at a few discrete zones, probably fractures or bedding-plane openings. The vertical connection between the zones in a single borehole with multiple producing zones commonly is negligible. This suggests that the formation is vertically anisotropic; the hydraulic conductivity is much larger in the horizontal direction than in the vertical direction. Some evidence of well-field-scale horizontal anisotropy exists, with maximum transmissivity aligned with the regional northeast strike of bedding, but this evidence is weak because of the small number of observation wells, particularly wells screened in isolated depth intervals. Analysis of recovery data after constant-pumping-rate aquifer tests and of drawdown during step tests suggests that a significant fraction, perhaps as much as 85 percent, of the drawdown in some production wells is due to well loss or skin effects in or very near the pumped well and is not caused by resistance to flow in the surrounding formations.

Suggested Citation

Goode, D.J., and Senior, L.A., 1998, Review of aquifer test results for the Lansdale area, Montgomery County, Pennsylvania, 1980–95: U.S. Geological Survey Open-File Report 1998, 76 p., https://doi.org/10.3133/ofr98294.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Hydrogeologic setting Study methods
  • Aquifer testing in the Lansdale area
  • Summary and conclusions
  • References cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Review of Aquifer Test Results for the Lansdale Area, Montgomery County, Pennsylvania, 1980–95
Series title Open-File Report
Series number 98-294
DOI 10.3133/ofr98294
Year Published 1998
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Pennsylvania Water Science Center
Description ix, 70 p. :ill., maps ;28 cm.
Country United States
State Pennsylvania
County Montgomery County
City Lansdale