Transmissivity Estimated From Brief Aquifer Tests of Domestic Wells and Compared With Bedrock Lithofacies and Position on Hillsides in the Appalachian Plateau of New York

Scientific Investigations Report 2020-5087
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Abstract

Procedures for undertaking and analyzing recovery from aquifer tests of 13 to 132 seconds (described in reports cited herein) were applied to 51 domestic drilled wells that penetrated bedrock outside major valleys in the part of the Appalachian Plateau of New York drained by the Susquehanna River. Transmissivities calculated from these tests ranged over three orders of magnitude in both the Catskill-Cattaraugus lithofacies (shales, mudstones, siltstones, medium to coarse sandstones, pebbly sandstones) and the Chemung-Hamilton lithofacies (shales, mudstones, siltstones, fine to medium sandstones). Median transmissivity values were 0.000425 foot squared per second (36.7 feet squared per day) in the Catskill-Cattaraugus lithofacies and 0.00055 foot squared per second (47.5 feet squared per day) in the Chemung-Hamilton lithofacies. The distributions of transmissivity values within the two lithofacies were likewise similar. The range and median values of transmissivity were also nearly the same on lower and midlevel hillsides and were only slightly greater on a few upper hillsides. Transmissivities estimated from such easily arranged and analyzed tests may be appropriate for estimating groundwater flux under the small gradients that prevail under natural conditions, but not under larger drawdowns and steeper gradients near clusters of domestic wells. Four of the 51 wells tested were also pumped for 10 to 32 minutes; analysis by the Theis recovery method yielded transmissivities consistent with the brief tests for 2 wells, but 7 to 9 times smaller for 2 wells.

Transmissivity values estimated by the PICKINGmodel were not significantly different from values estimated by an automated application of the Picking method (PPC-Recovery) at a probability of 95 percent. Transmissivities calculated by either method from data for time intervals of 120 seconds or less may be of limited practical value because they apply only to a small volume of bedrock close to the pumped well.

Suggested Citation

Randall, A.D., and Mills, A.C., 2020, Transmissivity estimated from brief aquifer tests of domestic wells and compared with bedrock lithofacies and position on hillsides in the Appalachian Plateau of New York: U.S. Geological Survey Scientific Investigations Report 2020–5087, 21 p., https://doi.org/10.3133/sir20205087.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Lithofacies Distribution in the Devonian Bedrock of the Appalachian Plateau of New York
  • Selection of Wells for Testing
  • Selection of a Procedure for Analyzing Brief Aquifer Tests of Domestic Wells
  • Analysis of 51 Brief Aquifer Tests
  • Longer Aquifer Tests of Five Wells
  • Comparison of PICKINGmodel to PPC-Recovery
  • Test Results Compared With Bedrock Lithofacies
  • Test Results Compared With Position on Hillsides
  • Summary
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Transmissivity estimated from brief aquifer tests of domestic wells and compared with bedrock lithofacies and position on hillsides in the Appalachian Plateau of New York
Series title Scientific Investigations Report
Series number 2020-5087
DOI 10.3133/sir20205087
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description Report: iv, 21 p.; Data Release
Country United States
State New York
Other Geospatial Appalachian Plateau
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
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