DTIC ADA441920: Simulation of Aquifer Tests and Ground-Water Flowpaths at the Local Scale in Fractured Shales and Sandstones of the Brunswick Group and Lockatong Formation, Lansdale, Montgomery County, Pennsylvania

56 Pages·3.9 MB·English

by  Defense Technical Information Center

SIMULATION OF AQUIFER TESTS AND GROUND-WATER
FLOWPATHS AT THE LOCAL SCALE IN FRACTURED SHALES
AND SANDSTONES OF THE BRUNSWICK GROUP AND
LOCKATONG FORMATION, LANSDALE, MONTGOMERY
COUNTY, PENNSYLVANIA
U.S. GEOLOGICAL SURVEY
Open-File Report 00-97
SE Keystone Rex NW
Soil & weathered rock
Bulk
aquifer
BC A
AB
C
B
CD
D BC
C
Bulk
aquifer
CD
D
0 100 Meters
Explanation
0 300 Feet Layers Properties
A, B, C, D High-permeability beds
VERTICAL EXAGGERATION 3X
AB, BC, CD Low-permeability beds
Bulk aquifer Undifferentiated Brunswick Group
prepared in cooperation with
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1. REPORT DATE 2. REPORT TYPE 3. DATES COVERED
2000 N/A -
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Simulation of Aquifer Tests and Ground-Water Flowpaths at the Local
5b. GRANT NUMBER
Scale in Fractured Shales and Sandstones of the Brunswick Group and
Lockatong Formation, Lansdale, Montgomery County, Pennsylvania 5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
U.S. Department of the Interior 1849 C Street, NW Washington, DC REPORT NUMBER
20240
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
11. SPONSOR/MONITOR’S REPORT
NUMBER(S)
12. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release, distribution unlimited
13. SUPPLEMENTARY NOTES
14. ABSTRACT
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF
ABSTRACT OF PAGES RESPONSIBLE PERSON

a. REPORT b. ABSTRACT c. THIS PAGE SAR 55
unclassified unclassified unclassified
Standard Form 298 (Rev. 8-98)
Prescribed by ANSI Std Z39-18
Cover: Cross-section of a three-dimensional ground-water flow model showing dipping high-
and low-permeability beds of the Brunswick Group in northwestern Lansdale, Pennsylvania (see
figure 24 of this report, and related discussion). “Keystone” and “Rex” designate properties where
aquifer tests were conducted to provide drawdown and recovery data for calibration of the
model.
SIMULATION OF AQUIFER TESTS AND GROUND-WATER
FLOWPATHS AT THE LOCAL SCALE IN FRACTURED SHALES
AND SANDSTONES OF THE BRUNSWICK GROUP AND
LOCKATONG FORMATION, LANSDALE, MONTGOMERY
COUNTY, PENNSYLVANIA
by Daniel J. Goode and Lisa A. Senior
U.S. GEOLOGICAL SURVEY
Open-File Report 00-97
prepared in cooperation with
U.S. ENVIRONMENTAL PROTECTION AGENCY
Lemoyne, Pennsylvania
2000
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director
For additional information Copies of this report may be
write to: purchased from:
District Chief U.S. Geological Survey
U.S. Geological Survey Branch of Information Services
840 Market Street Box 25286
Lemoyne, Pennsylvania 17043-1586 Denver, Colorado 80225-0286
Email: [email protected] Telephone: 1-888-ASK-USGS
CONTENTS
Page
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Previous work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Hydrogeologic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Ground-water system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Simulation of ground-water flow at the local scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Limitations and uncertainties in predictive simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
North-central Lansdale model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Aquifer-test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Model structure and boundary conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Aquifer-test simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Effect of pumping on ground-water flowpaths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Northwestern Lansdale models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Aquifer-test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Keystone Hydraulics site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Rex site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Model structure and boundary conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Aquifer-test simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Effect of pumping on ground-water flowpaths. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Pumping well Mg-625 under 1997 conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Additional pumping at well Mg-1610 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Additional pumping at well Mg-1620 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
References cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
iii
ILLUSTRATIONS
Page
Figure1.--Location of North Penn Area 6 site, Lansdale, Pa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.--Bedrock geology in area of Lansdale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3.--Schematic conceptual model of ground-water flow system for fractured sedimentary-
rock aquifer with dipping beds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
4.--Boundaries and stream cells of regional ground-water flow model grid and areas of local-
scale models at the John Evans and Sons property (Evans) in north-central Lansdale
and at the Keystone Hydraulics property (Keystone) and the J.W. Rex Co. property
(Rex) in northwestern Lansdale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.--Simulated hydraulic head in model layer 2, which represents the upper 328 feet of
unweathered, fractured bedrock, and stream and well contributing areas in Lansdale
area for 1997 conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
6.--Well locations and drawdown at end of pumping well Mg-1609 at the John Evans and
Sons property in north-central Lansdale, November 21, 1997 . . . . . . . . . . . . . . . . . . . .13
7.--Cross-section of open intervals of wells, static depth to water, and drawdown at end of
pumping at the John Evans property in north-central Lansdale,
November 21, 1997.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
8.--Cross-section of open intervals of wells nearly on strike with the pumped well, static
depth to water, and drawdown at end of pumping at the John Evans and Sons property
in north-central Lansdale, November 21, 1997 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
9.--Measured water levels at the John Evans and Sons property in north-central Lansdale,
November 20-22, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
10.--Measured and simulated drawdown, using two-aquifer model of Neuman and
Witherspoon (1969), in wells Mg-67, Mg-80, Mg-163 and Mg-1666 at the John Evans
and Sons property in north-central Lansdale, November 21, 1997. . . . . . . . . . . . . . . .17
11.--Cross section of local-scale model of ground-water flow at the John Evans and Sons
property in north-central Lansdale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
12.--Well location and horizontal grid configuration for simulation of local-scale ground-
water flow at the John Evans and Sons property in north-central Lansdale, showing
local-scale grid and overlap region for incorporation of regional-model flux boundary
conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
13.--Measured and simulated drawdown, using local-scale flow model, in wells Mg-67,
Mg-80, Mg-163, and Mg-1666 at the John Evans and Sons property in north-central
Lansdale, November 21, 1997.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
14.--Well locations and simulated drawdown in model layer 6 (containing the pumped well)
after 7.93 hours of pumping well Mg-1609 at a rate of 9.1 gallons per minute at the John
Evans and Sons property in north-central Lansdale. . . . . . . . . . . . . . . . . . . . . . . . . . . .22
15.--Simulated contributing area for well Mg-1609 pumping at a rate of 10 gallons per
minute at the John Evans and Sons property in north-central Lansdale. . . . . . . . . . .23
iv
ILLUSTRATIONS--continued
Page
Figure16.--Well locations and drawdown at end of pumping well Mg-1610 at the Keystone
Hydraulics property in northwestern Lansdale, November 18, 1997. . . . . . . . . . . . . .25
17.--Cross-section of open intervals of wells, static depth to water, and drawdown at end of
pumping at the Keystone Hydraulics property in northwestern Lansdale,
November 18, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
18.--Measured water levels at the Keystone Hydraulics property in northwestern Lansdale,
November 17-19, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
19.--Measured and simulated drawdown, using anisotropic model of Papadopulos (1965),
in wells Mg-67, Mg-80, Mg-163, and Mg-1620 at the Keystone Hydraulics property in
northwestern Lansdale, November 18, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
20.--Well locations and recovery at end of shutdown of well Mg-625 at the J.W. Rex Co.
property in northwestern Lansdale, October 27, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . .30
21.--Cross-section of open intervals of wells, static depth to water, and recovery at end of
shutdown at the J.W. Rex Co. property in northwestern Lansdale,
October 27, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
22.--Measured water levels in wells Mg-82, Mg-157, Mg-624, Mg-625, Mg-1639, Mg-1640,
and Mg-1641 at the J.W. Rex Co. property in northwestern Lansdale,
October 23-31, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
23.--Location of the regional-scale model domain and the embedded local-scale models at
the Keystone Hydraulics property (Keystone) and the J.W. Rex Co. property (Rex) in
northwestern Lansdale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
24.--Hydrogeologic cross-section in the downdip direction in northwestern Lansdale.. . .34
25.--Measured and simulated drawdown in wells (A) Mg-67, Mg-80, Mg-163, Mg-1620, and
(B) Mg-1611 and Mg-1620 at the Keystone Hydraulics property in northwestern
Lansdale, November 18, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
26.--Measured and simulated water-level recovery in wells (A) Mg-82, Mg-1639, Mg-1640,
and (B) Mg-157, Mg-624, and Mg-1641 at the Rex Co. property,
October 26-27, 1997. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
27.--Simulated water levels in the upper part of the bedrock aquifer in Lansdale and vicinity
for 1997 conditions and contributing area for well Mg-625 pumping at a rate of 30
gallons per minute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
28.--Contributing areas for well Mg-625 pumping at a rate of 30 gallons per minute in
Lansdale for 1997 conditions simulated using the local-scale model developed here
and the regional-scale model of Senior and Goode (1999).. . . . . . . . . . . . . . . . . . . . . . .41
29.--Simulated water levels in the upper part of the bedrock aquifer in Lansdale and
vicinity and contributing area for well Mg-1610 pumping at a rate of 10 gallons per
minute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
v
ILLUSTRATIONS--continued
Page
Figure30.--Simulated water levels in the upper part of the bedrock aquifer in Lansdale and
vicinity and contributing area for well Mg-1620 pumping at a rate of 10 gallons per
minute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
TABLES
Page
Table 1.--Optimum and approximate, individual, 95-percent confidence-interval values for
hydraulic conductivity, anisotropy ratio, and recharge for calibrated simulation of
ground-water flow in and near Lansdale, Pa.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.--Selected sites and main volatile organic compounds where soil contamination or proba-
ble sources of ground-water contamination have been identified in Lansdale. . . . . . .9
3.--Optimum and approximate, individual, 95-percent confidence-interval values for hy-
draulic conductivity and specific storage for calibrated simulation of ground-water
flow in north-central Lansdale. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.--Optimum and approximate, individual, 95-percent confidence-interval values for hy-
draulic conductivity and specific storage for calibrated simulation of ground-water
flow in northwestern Lansdale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
5.--Annual average pumping rates for wells in and near Lansdale during 1997. . . . . . . . . .39
vi
CONVERSION FACTORS, ABBREVIATIONS, AND VERTICAL DATUM
Multiply By To obtain
Length
inch (in) 25.4 millimeter
foot (ft) 0.3048 meter
mile (mi) 1.609 kilometer
Area
square foot (ft2) 0.09290 square meter
square mile (mi2) 2.590 square kilometer
Volume
gallon (gal) 3.785 liter
gallon (gal) 0.003785 cubic meter
Flow rate
foot per day (ft/d) 0.3048 meter per day
gallon per minute (gal/min) 0.06309 liter per second
Hydraulic conductivity
foot per day (ft/d) 0.3048 meter per day
Transmissivity
foot squared per day (ft2/d) 0.09290 meter squared per day
Vertical datum: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929—a
geodetic datum derived from a general adjustment of the first-order level nets of the United States and
Canada, formerly called Sea Level Datum of 1929.
vii