Aquifer Performance Test Report

Aquifer Performance Test Report
Aquifer Performance
Test Report
P r e pa re d for
Butte Coun ty
D e pa r tm en t o f W a t er and
Reso urce Conservation
Apr il 26 , 20 13
Table of Contents
List of Figures ..................................................................................................................................................... iii List of Tables ...................................................................................................................................................... vi List of Abbreviations ........................................................................................................................................ viii 1. Introduction............................................................................................................................................... 1-1 1.1 Purpose and Scope ........................................................................................................................ 1-1 1.2 Overview of Project ........................................................................................................................ 1-2 1.3 Overview of Aquifer Testing ........................................................................................................... 1-3 1.4 Report Format ................................................................................................................................ 1-4 2. Review of Existing Aquifer Tests .............................................................................................................. 2-1 2.1 1993 Aquifer Testing for startup of Koppers Company Groundwater Extraction System ......... 2-1 2.1.1 Hydrogeology .................................................................................................................... 2-2 2.1.2 Step Drawdown Aquifer Tests ......................................................................................... 2-4 2.1.3 Constant Rate Pumping Test........................................................................................... 2-7 2.1.4 Usability of Data ............................................................................................................. 2-11 2.2 1996 M&T Chico Ranch Aquifer Test ......................................................................................... 2-12 2.2.1 Hydrogeology .................................................................................................................. 2-13 2.2.2 June 1995 Aquifer Testing ............................................................................................ 2-14 2.2.3 May 1996 Aquifer Testing ............................................................................................. 2-16 2.2.4 Usability of Data ............................................................................................................. 2-17 2.3 March 2009 Glenn-Colusa Irrigation District Test-Production Well Installation and Aquifer
Testing .......................................................................................................................................... 2-21 2.3.1 Hydrogeology .................................................................................................................. 2-22 2.3.2 Step Drawdown and 24-Hour Constant Rate Aquifer Tests ........................................ 2-24 2.3.3 28-Day Constant Rate Aquifer Test .............................................................................. 2-26 2.3.4 Usability of Data ............................................................................................................. 2-28 2.4 October 2009 Aquifer Test Report: Orland Site ......................................................................... 2-28 2.4.1 Hydrogeology .................................................................................................................. 2-29 2.4.2 Step-Drawdown Aquifer Test ......................................................................................... 2-30 2.4.3 9-Day Constant Rate Aquifer Test ................................................................................. 2-31 2.4.4 Usability of Data ............................................................................................................. 2-33 3. Methods and Procedures for LTA Aquifer Test and Analysis ................................................................. 3-1 3.1 Hackett Property Aquifer Test ....................................................................................................... 3-1 3.2 M&T Ranch Aquifer Test ................................................................................................................ 3-6 3.3 Esquon Ranch Aquifer Test ........................................................................................................... 3-9 3.4 Groundwater Sampling ................................................................................................................ 3-17 4. Results and Analysis of LTA Aquifer Tests .............................................................................................. 4-1 4.1 Hydrostratigraphy ........................................................................................................................... 4-2 ii
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4.2 Hackett Property Aquifer Test Analysis ......................................................................................... 4-2 4.2.1 Conceptual Hydrogeologic Model ................................................................................... 4-2 4.2.2 Quantitative Aquifer Test Analysis .................................................................................. 4-4 4.3 M&T Ranch Aquifer Test Analysis ............................................................................................... 4-12 4.3.1 Conceptual Hydrogeologic Model ................................................................................. 4-12 4.3.2 Quantitative Aquifer Test Analysis ................................................................................ 4-15 4.4 Esquon Ranch Aquifer Test ......................................................................................................... 4-20 4.4.1 Conceptual Hydrogeologic Model ................................................................................. 4-20 4.4.2 Quantitative Aquifer Test Analysis ................................................................................ 4-24 5. Groundwater Sampling ............................................................................................................................ 5-1 6. References ................................................................................................................................................ 6-1 Appendix A: Existing Aquifer Test Studies .........................................................................................................A Appendix B: AQTESOLVTM Analysis, DWR 1996 Aquifer Test .......................................................................... B Appendix C: DWR Geologic Well Logs – Esquon Aquifer Test ........................................................................ C Appendix D: Chain-of-Custody Forms and Analytical Laboratory Reports ...................................................... D Appendix E: Detail Aquifer Test Analysis LTA Project ........................................................................................E Appendix F: AQTESOLV™ Diagnostic Statistical Reports .................................................................................. F List of Figures
Figure 1-1. Location Map of Aquifer Testing Program of the LTA Recharge Project.................................. 1-2 Figure 2-1. Site Location Map of Former Koppers Company Facility and Off-Property Groundwater
Extraction System ..................................................................................................................................... 2-2 Figure 2-2. llustrating Hydrogeologic Conceptual Model Developed for Project. An example of a
paleo-valley is shown at the top of diagram between RI-7/13 and RI-10. .......................................... 2-3 Figure 2-3. Well Location Map for Extraction Well Aquifer Test .................................................................. 2-5 Figure 2-4. Generalized Hydrogeologic Cross Section Showing Construction Details of Extraction
Wells Used for Aquifer Test ...................................................................................................................... 2-6 Figure 2-5. Time Drawdown Curve and Cooper-Jacob Straight Line Solution for Extraction Well EW-3... 2-8 Figure 2-6. Time Drawdown Curve and Cooper-Jacob Straight Line Solution for Extraction Well EW-4... 2-9 Figure 2-7. Distance Drawdown Plot at Time Equals 100 Minutes ............................................................ 2-9 Figure 2-8. Distance Drawdown Plot at Time Equals 1,000 Minutes ....................................................... 2-10 Figure 2-9. Arrows presented on cross section represent the direction of groundwater flow and
illustrate the lateral movement of groundwater between the different aquifer formations.
Lower Tuscan Formation designated as Mehrten Formation in report. ............................................. 2-12 Figure 2-10. Location of Pumping Well used for LTA Project (PW-MT-1) and the DWR M&T
Aquifer Test (PW-MT-4)........................................................................................................................... 2-13 Figure 2-11. Time Drawdown Plot for 1995 Step Drawdown Test ........................................................... 2-14 iii
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Figure 2-12. Location Map Showing Location of Wells Monitored during 1995 Aquifer Test ................ 2-15 Figure 2-13. Time Drawdown Graph for Monitoring Well 24B01 During 1996 Constant-Discharge
Aquifer Test ............................................................................................................................................. 2-16 Figure 2-14. Derivative (Blue) and Drawdown Curves (Red) for Well 24B01 during May 1996
DWR Aquifer Test.................................................................................................................................... 2-18 Figure 2-15. Cooper Jacob Straight Solution for Well 24B01 during May 1996 DWR Aquifer Test ....... 2-19 Figure 2-16. Moench (1985) solution for well 24B01 during May 1996 aquifer test. Curve fits for
drawdown (red) and derivative plot (green) area shown in blue. ........................................................ 2-20 Figure 2-17. Neuman-Witherspoon (1969) solution for well 24B01 during May 1996 aquifer test.
Curve fits for drawdown (red) and derivative plot (green) area shown in blue................................... 2-21 Figure 2-18. Location Map for GCID Test Production Well and Observation Well ................................... 2-22 Figure 2-19. Surface and Subsurface Extent of Tuscan, Tehama, and Stony Creek Fan Alluvium ........ 2-23 Figure 2-20. Time Drawdown Plot for 12-Hour Step-Drawdown Aquifer Test .......................................... 2-25 Figure 2-21. Time Drawdown Plot and Jacob Straight Line Solution for Test Production Well
During 24-Hour Constant-Discharge Aquifer Test ................................................................................ 2-25 Figure 2-22. Location of Test Production and Observations Well For 28-Day Constant Rate Test ........ 2-26 Figure 2-23. Jacob Straight Line Method Using Time Drawdown Data from 28-Day Constant
Rate Aquifer Test for Newly Installed Deep Observation Well (N001M) ............................................. 2-27 Figure 2-24. Distance Drawdown Plot at 40,000 Minutes for 28-Day Constant Rate Aquifer Test ....... 2-27 Figure 2-25. Location Map Showing Test Well and Observation Wells Used for Aquifer Test ................ 2-29 Figure 2-26. Conceptual Profile of Subsurface Site Conditions, Crystal Geyser Facility ......................... 2-30 Figure 2-27. Time Drawdown Plot Produced During Step-Drawdown Aquifer Test for Crystal
Geyser Aquifer Testing. Inset of Figure Shows Specific Capacities Calculated from the Test ........ 2-31 Figure 3-1. Hackett Property Aquifer Test Location Illustrating Monitoring Well and Pumping Well
Locations ................................................................................................................................................... 3-2 Figure 3-2. Picture of typical pressure transducer used for LTA aquifer tests.
Length of cable will vary. .......................................................................................................................... 3-3 Figure 3-3. Flexim Fluxus ADM 6725 Ultrasonic Flow Meter Used To Measure Flow Rates
In Pumping Well During Aquifer Tests ..................................................................................................... 3-4 Figure 3-4. M&T Ranch Aquifer Test Location Illustrating Monitoring Well and Pumping Well Locations3-7 Figure 3-5. Esquon Ranch Aquifer Test Location Illustrating Monitoring Well and Pumping Well
Locations ................................................................................................................................................. 3-10 Figure 3-6. Ibutton used to Monitor Startup and Shutdown of Irrigation Wells ....................................... 3-11 Figure 3-7. Plot of drawdown data recorded by pressure transducer and temperature data
recorded by ibutton over same time period at irrigation well PW-ESQ-13. When irrigation well
is turned on, temperature data becomes more constant reflecting temperature of water within
discharge pipe. When irrigation well turns off, temperature data reflects fluctuations between
night time and day time. ........................................................................................................................ 3-12 Figure 4-1. Generalized Geologic Cross Section, Hackett Property Aquifer Test. Pumping Well,
PW-HP-1. Observation Well, MW-HP-1. .................................................................................................. 4-3 iv
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Figure 4-2. Drawdown Curves Plotted On Log-Log Diagram for Three Screens of Hackett Property
Observation Well MW-HP-1 ...................................................................................................................... 4-4 Figure 4-3. Derivative (Green) and Drawdown (Black) Curves for Pumping Well PW-HP-1 ....................... 4-5 Figure 4-4. Derivative (Green) and Drawdown (Red) Curves for Observation Well MW-HP-1Intermediate ............................................................................................................................................. 4-6 Figure 4-5. Cooper-Jacob Straight Solution for Pumping Well PW-HP-1 ..................................................... 4-7 Figure 4-6. Cooper-Jacob Straight Solution for Observation Well MW-HP-1 Intermediate Screen ........... 4-8 Figure 4-7. Moench (1985) Case 3 Solution For Drawdown Curve Produced For Observation
Well MW-HP-1 Intermediate Screen Interval During Hackett Property Aquifer Test ............................ 4-9 Figure 4-8. Neuman-Witherspoon Solution for MW-HP-1 Intermediate/Shallow Screen Zones ............ 4-10 Figure 4-9. Theis Recovery Plot for Observation Well MW-HP-1 Intermediate ......................................... 4-12 Figure 4-10. Generalized Geologic Cross Section, M&T Ranch Aquifer Test. Pumping Well,
PW-MT-1. Observation Well, MW-MT-1. ............................................................................................... 4-13 Figure 4-11. Drawdown Curves Plotted on Log-Log Diagram for Three Observation Well Screens
within MW-MT-1 Used for M&T Ranch Aquifer Test ............................................................................. 4-14 Figure 4-12. Drawdown Curves Plotted for Intermediate and Deep Well Screens of
Observation Well MW-MT-1 on Semi-Log Diagram ............................................................................... 4-15 Figure 4-13. Derivative (Green) and Drawdown (Red) Curves for Observation Well MW-MT-1-Shallow 4-16 Figure 4-14. Cooper-Jacob Straight Solution for Observation Well MW-MT-1 Shallow Screen ............... 4-17 Figure 4-15. Moench (1985) Case 1 Solution for Observation Well MW-MT-1 Shallow, M&T Ranch
Aquifer Test ............................................................................................................................................. 4-18 Figure 4-16. Neuman-Witherspoon (1969) Solution for Observation Well MW-MT-1 Shallow,
M&T Ranch Aquifer Test. T2 and S2 Represent The T and S Values for the Unpumped Aquifer. ... 4-19 Figure 4-17. Generalized geologic cross section, Esquon Ranch Aquifer Test. Tuscan Formation
in this area is part of the LTA. Pumping Wells, PW-ESQ-39 and PW-ESQ-40. Observation Well,
MW-ESQ-1. .............................................................................................................................................. 4-21 Figure 4-18. Drawdown curves plotted on Semi-log diagram for four observation well screens
within MW-ESQ-1 used for Esquon Ranch aquifer test. Figure also shows bars indicating
startup and shutdown of irrigation wells, weather events that effected the duration of the
aquifer tests, and a brief evaluation of each of the curves with respect to validity for use in
quantitative curve matching analysis. .................................................................................................. 4-23 Figure 4-19. Derivative (Green) And Drawdown (Red) Curves For Observation Well MW-ESQ-1Intermediate-Shallow ............................................................................................................................. 4-24 Figure 4-20. Derivative (Green) And Drawdown (Red) Curves For Observation Well MW-ESQ-1Intermediate-Deep ................................................................................................................................. 4-25 Figure 4-21. Distance drawdown method at time equals 1,496 minutes during the Esquon Ranch
test 1 aquifer test. Drawdowns recorded at this time were: PW-ESQ-13 = 2.1 feet;
PW-ESQ-16 = 2.88 feet; PW-ESQ-39 = 36.04 feet; and PW-ESQ-40 = 6.5 feet. ............................... 4-27 Figure 4-22. Moench (1985) Case 3 solution for observation well MW-ESQ-1 Intermediate Shallow,
Esquon Ranch test 2 aquifer test. ......................................................................................................... 4-28 v
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Figure 4-23. Moench (1985) Case 3 solution for observation well MW-ESQ-1 Intermediate Deep,
Esquon Ranch test 2 aquifer test. ......................................................................................................... 4-29 Figure 4-24. Moench (1985) Case 3 solution for observation well MW-ESQ-1 Intermediate
Shallow using drawdown data from both test 1 and test 2 during the Esquon Ranch aquifer test. 4-31 List of Tables
Table 1-1. Hydraulic conductivity values of common aquifer materials. Modified from Bear (1972) ..... 1-4 Table 2-1. Well construction details for wells used during aquifer testing. Reproduced from
Dames and Moore (1993). ...................................................................................................................... 2-7 Table 2-2. Summary of DWR WTAQ2 Analysis for Potential Drawdown Impacts Related to
Operation of Proposed Production Wells .............................................................................................. 2-17 Table 2-3. Well Construction Details for Newly Installed Test Production and Nested
Observation Well..................................................................................................................................... 2-24 Table 2-4. Well Construction details of test production and observation wells used for
28-day constant discharge test. Reproduced Table 5 from DWR (2009). ........................................ 2-26 Table 2-5. Well Construction Details for Test Well and Observation Wells .............................................. 2-32 Table 2-6. Summary of Aquifer Test Analysis during 9-day Constant Rate Aquifer Test ......................... 2-33 Table 3-1. Well Construction Details for Hackett Property Aquifer Test ..................................................... 3-2 Table 3-2. Summary of Static Water Level Measurements......................................................................... 3-3 Table 3-3. Pumping Rates Recorded During Hackett Property Aquifer Test .............................................. 3-5 Table 3-4. Hand Water Level Measurements Collected During Hackett Property Aquifer Test ................ 3-6 Table 3-5. Well construction details for M&T Ranch Aquifer Test .............................................................. 3-8 Table 3-6. Summary of Static Water Level Measurements Prior to M&T Ranch Aquifer Test .................. 3-8 Table 3-7. Pumping Rates Recorded During M&T Ranch Aquifer Test ...................................................... 3-9 Table 3-8. Well construction details for Esquon Ranch Aquifer Test ....................................................... 3-11 Table 3-9. Static Water Levels Measured Prior to Startup tf Esquon Ranch Aquifer Test 1 ................... 3-13 Table 3-10. Corrections for Lowering of Transducers ............................................................................... 3-13 Table 3-11. Pumping Rates Recorded During Esquon Ranch Aquifer Test 1 .......................................... 3-14 Table 3-12. Hand Water Level Measurements Collected During Esquon Ranch Aquifer Test 1 ............ 3-15 Table 3-13. Time Corrections MW-ESQ-1 Transducers During Esquon Ranch Aquifer Test 2 ................ 3-15 Table 3-14. Pumping Rates Recorded During Esquon Ranch Aquifer Test 2 .......................................... 3-16 Table 3-15. Hand Water Level Measurements for MW-ESQ-1 Collected During Esquon Ranch
Aquifer Test 2.......................................................................................................................................... 3-17 Table 3-16. Summary of Groundwater Sample Collection ........................................................................ 3-17 Table 4-1. Summary of T, S, and K values from Moench (1985) solution, Hackett Property
aquifer test. ............................................................................................................................................... 4-9 vi
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Table 4-2. Estimated T, S, And K Values For Unpumped Shallow Aquifer And Overlying
Aquitard For Hackett Property Aquifer Test .......................................................................................... 4-11 Table 4-3. Summary of T, S, and K Values from Moench (1985) Solution, M&T Ranch Aquifer
Test and from Neuman-Witherspoon Solution for DWR (1996) Aquifer Test ..................................... 4-19 Table 4-4. Estimated T, S, and K values for Unpumped Shallow Aquifer and Overlying Aquitard
for M&T Ranch Aquifer Test ................................................................................................................... 4-20 Table 4-5. T, S, and K Values Calculated Using Cooper-Jacob Straight Line Method for the
Esquon Ranch Test 1 And Test 2 Aquifer Tests.................................................................................... 4-26 Table 4-6. Summary of T, S, and K Values from Moench (1985) Solution for Esquon Ranch
Aquifer Test ............................................................................................................................................. 4-30 Table 4-7. Summary of S/S’ Values Calculated from Theis Recovery Method for Esquon
Ranch Aquifer Test ................................................................................................................................. 4-31 Table 5-1. Summary of Groundwater Samples – LTA Aquifer Testing........................................................ 5-1 vii
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Aquifer Performance Test Report
List of Abbreviations
BC
Brown and Caldwell
bgs
below ground surface
CEQA
California Environmental Quality Act
DWR
California Department of Water Resources
ft
feet
ft2/day
feet2 per day
GCID
Glenn-Colusa Irrigation District
GIS
Geographic Information System
gpm
gallons per minute
gpm/ft
gallons per minute per foot
IRWM
Integrated Regional Water Management
IWFM
Integrated Water Flow Model
LTA Project
Lower Tuscan Aquifer Monitoring,
Recharge, and Data Management Project
Qd
Quaternary deposits
S
Storativity
T
Transmissivity
viii
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Section 1
Introduction
This report presents results from the review of existing aquifer performance tests and completion of
three new aquifer performance tests conducted for Task 5, Aquifer Performance Tests, for the Lower
Tuscan Aquifer Monitoring, Recharge, and Data Management Project (LTA Project). These activities were
conducted in accordance with Attachment Two Section A2.2.5.2 of the County of Butte Contract Number
18050 dated January 31, 2010 between Butte County and Brown and Caldwell (BC). A description of
the overall LTA Project is presented in the Initial Study/Proposed Mitigated Negative Declaration
prepared by the Butte County, Department of Water and Resource Conservation in May 2010.
1.1 Purpose and Scope
Reanalysis of existing aquifer performance tests was conducted to assess if these tests were performed
consistent with industry standards whereby the data reported can be used to provide better
understanding of the Lower Tuscan Formation aquifer system’s hydraulic performance. Completion of
the three new aquifer performance tests were conducted to: 1) collect basic aquifer data including
transmissivity (T) and storativity (S) expanded to areas and zones of the LTA not assessed during
previous tests; and, 2) to gain a better understanding of the vertical interformational leakage between
the Lower Tuscan Formation aquifer system and other hydraulic units. The data developed from these
tasks will be used to assess input parameters used for the Butte County Integrated Water Flow Model
(IWFM) as part of the Final Report for the LTA Project.
The aquifer performance testing was conducted at existing irrigation and production wells – no new
production wells were constructed for this project at three sites as shown on Figure 1-1. For this report
the sites are referred to from north to south as the Hackett property, the M&T Ranch, and the Esquon
Ranch. The water extracted for each test was used as part of existing irrigation practices and distributed
according to normal operating conditions at each location.
1-1
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Aquifer Performance Test Report
Figure 1-1. Location Map of Aquifer Testing Program of the LTA Recharge Project
The purpose of this report is to summarize results of the review of existing aquifer tests, the methods
and procedures used to conduct each of the new tests, and, to present the results of the aquifer
performance analysis. A detailed scope of work for the aquifer performance tests was presented in the
February 15, 2011 Technical Memorandum No. 3, Aquifer Performance Test Work Plan prepared by BC
(Appendix C of First Quarter 2011 Quarterly Report) and included:

Pre-test setup for each aquifer performance test including selection of production wells and
equipment used to monitor the test;

Methods used to conduct and monitor the aquifer performance tests; and

Methods used for analysis of the tests.
1.2 Overview of Project
The LTA Project consists of seven tasks as follows:
Task 1 – California Environmental Quality Act (CEQA) Initial Study
Task 2 – Technical Steering Committee
Task 3 – Development of Geographic Information System (GIS) Geodatabase
1-2
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Aquifer Performance Test Report
Section 1
Task 4 – Aquifer Recharge Assessment
Task 5 – Installation of Groundwater Monitoring Wells
Task 6 – Aquifer Performance Testing
Task 7 – Public Outreach
The Tuscan Aquifer system, a regional aquifer of the Sacramento Valley Groundwater Basin, is among
the principal water bearing units in Butte County. For this project, the Tuscan Formation has been
divided into four units, labeled A through D, as defined by Helly and Hardwood (1985). Units A and B
define the LTA, the subject of this study, and units C and D define the Upper Tuscan Aquifer. The
approximate extent of the LTA within the project boundaries is shown on Figure 1-1.
Butte County has been awarded grant funds from the California Department of Water Resources (DWR)
through Proposition 50 (Water Security, Clean Drinking Water, Coastal and Beach Protection Act of
2002) for implementation of the LTA Project. Included as part of Proposition 50, is the Integrated
Regional Water Management (IRWM) Grant Program. Butte County is administering the LTA Project in
partnership with the Four County Memorandum o f Understanding Group (Butte, Glenn, Colusa, Tehama,
Shasta and Sutter Countiesnow called the Northern Sacramento Valley Integrated Regional Water
Management Plan area
The LTA Project is a scientific investigation that will develop data and analytical tools to improve the
understanding of the aquifer. Specifically, the LTA Project is a scientific field investigation that seeks to
improve the scientific understanding of the properties of the LTA system including:
 The physical parameters affecting percolation of surface water to the LTA.
 The interaction between surface water and the LTA.
 Recharge contributions from other aquifers to the LTA.
 Measurements of standard aquifer properties and their variability.
 Identification of natural recharge areas under current hydrologic conditions.
 Identification of recharge areas under increase utilization.
 How additional pumping may impact the aquifer and surface water.
In addition, the project included development of a comprehensive GIS Geodatabase to store data
collected during the duration of the project. As part of the GIS Geodatabase, the project also included
development of a field data collection tool that improved the quality of data collected in the field that
was incorporated into the geodatabase. Finally, the project included a public outreach program that will
heighten public awareness and understanding of the aquifer.
1.3 Overview of Aquifer Testing
An aquifer test is a field test where a well is pumped at a controlled rate and water-level response, or
drawdown, is measured within the pumping well and one or more surrounding observation wells. Two
types of aquifer tests are discussed in this report, step drawdown aquifer tests and constant rate aquifer
tests.
A step drawdown aquifer test is a single-well pumping test designed to investigate the performance of a
pumping well under controlled variable discharge conditions. In a step drawdown test, the discharge
rate, or pumping rate, in the pumping well is increased from an initially low constant rate through a
sequence of pumping intervals (steps) of progressively higher constant rates. Each step is typically of
equal duration, lasting from approximately 30 minutes to 2 hours. The primary objective of a step
drawdown aquifer test is to evaluate well performance criteria such as well loss and well efficiency that
can be used to select an appropriate pumping rate for a constant rate aquifer test. The data from a step
1-3
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Section 1
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drawdown aquifer test can also be used to provide preliminary estimates of hydraulic properties of an
aquifer system such as transmissivity and hydraulic conductivity.
The goal of a constant rate aquifer test is to estimate hydraulic properties of an aquifer system. A
constant rate aquifer tests consists of pumping a well at a single rate for a long enough duration to see
drawdown responses (decline in water levels) from one or more observation wells. For the pumped
aquifer, one seeks to determine hydraulic conductivity, transmissivity, and storativity. Hydraulic
conductivity, represented in this report with a “K”, describes the ease with which water can move
through pore spaces or fractures. Average K values for unconsolidated sedimentary materials are
provided on Table 1-1.
Table 1-1. Hydraulic conductivity values of common aquifer materials. Modified from Bear (1972)
K values in units of feet per day (ft/day)
100,000 10,000 1,000 100 10 1 0.1 0.01 0.001 0.0001 0.00001
Aquifer Quality
Good
Typical Aquifer Material Well Sorted Gravel
Well Sorted Sand or
Sand and Gravel
Poor
None
Very Fine Sand
Clay
Transmissivity, represented by a “T” in this report, is a measure of the ability of an aquifer to produce
water and is equal to K times the thickness of the aquifer (represented with a “b” in this report), or T =
Kb. As such, a T value for a 10 foot thick well sorted sand with a K value of 100 would be the same as a
100 foot thick fine sand with a K value 10. Units of T are feet squared per day (ft2/day). Typically, T
values of less than 100 ft2/day will supply only enough water for domestic wells or other low-yield
purposes. In wells with T values greater than 1,300 ft2/day, the production yields are typically sufficient
for industrial, municipal, or irrigation use.
Storativity, represented by an “S” in this report, is a physical property that characterizes the capacity of
an aquifer to release groundwater. Specifically, it is defined as the volume of water an aquifer releases
from or takes into storage, per unit surface area per change in head and is a unitless number. The
storativity of a confined aquifer typically ranges from 0.00005 to 0.005 (Todd 1980) whereas for
unconfined aquifers, storativity ranges from 0.1 to 0.3 (Todd, 1980).
For the LTA project, aquifer properties are estimated from the constant-rate aquifer test by fitting
mathematical models to drawdown data through a procedure known as curve matching. Curve matching
may be performed using type-curve methods on log-log plots or straight-line methods on semi-log plots
(Figure 3). To allow for a more detailed analysis of the cuver matching process, the software package
AQTESOLV™ was used to analyze the drawdown data collected for the LTA project. This software
package also includes several diagnostic tools to assess flow regimes to select the appropriate type
curve solution for the data including derivative analyses that are useful for detecting deviations in the
rate of displacement change. A more detailed discussion of the use of the AQTESOLV™ software
package is presented in Section 4 and Appendix E.
1.4 Report Format
The format of this report has been organized to reflect the tasks and sequence of events that occurred
during each aquifer test. Section 2 summarizes the review of existing aquifer tests. Section 3
summarizes the methods and procedures used for conducting each of the new three aquifer
performance tests including setup and sampling of discharge water for analysis of isotopes and general
parameters. A discussion of the analysis and results of the aquifer performance tests are presented in
1-4
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Section 1
Section 4 and the results of the laboratory analysis of groundwater samples are presented in Section 5
References cited are presented in Section 6. An overall evaluation of these results as they relate to
recharge within the LTA and comparison to the Butte County IWFM will be presented in the project Final
Report scheduled to be issued in May 2013.
1-5
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Section 2
Review of Existing Aquifer Tests
As discussed in Section 1.1, the evaluation of existing aquifer performance tests was conducted to assess if
these tests were performed consistent with industry standards whereby the data reported can be used to
provide better understanding of the Lower Tuscan Formation aquifer system’s hydraulic performance. The
Tuscan Project listed six previously conducted tests for consideration. These included:

Sun City, Tehama County (Tehama County)

Deer Creek Irrigation District, Tehama County (DWR)

M&T Ranch, Butte County (DWR)

GCID -1, Glenn County (DWR)

Orland/Artois, Glenn County (DWR)

Western Canal/Fenn, Butte County (DWR)
The Technical Steering Committee (TSC) was consulted on these and other test for inclusion in this task. Based
on input from the TSC, the following four existing aquifer test studies were identified for this task:

A July 1993 report describing aquifer tests conducted as part of the startup of a groundwater extraction
system to address impacts associated with the former Koppers Company wood treating facility located in
Oroville, California (Dames & Moore, 1993).

A December 1996 report describing two aquifer tests conducted on the M&T Ranch by the DWR as part of a
conjunctive use assessment (DWR, 1996).

A March 2009 report discussing aquifer testing of a test production well installed for the Glenn-Colusa
Irrigation District (DWR, 2009)

An October 5, 2009 report discussing aquifer testing conducted for a test well installed for the Crystal
Geyser Water Company (Crystal Geyser, 2009).
Copies of these reports are provided on CD in Appendix A. A brief summary of the methods and procedures used
for each of these tests followed by an assessment of the reported results is provided below.
2.1 1993 Aquifer Testing for startup of Koppers Company Groundwater
Extraction System
The results of the aquifer testing conducted for this project are presented in a report entitled “Extraction Well
Field Report, Initial Phase Off-Property Groundwater Remedial Action, Koppers Company, Incorporated,
Superfund Site” prepared by Dames and Moore (1993). The former Koppers Company is located in south
Oroville, California on Baggett Marysville Road (Figure 2-1). The overall report presents results of activities
completed during the installation and startup of a groundwater extraction well field installed as part of a
remedial action to address impacts to groundwater that migrated offsite of the Koppers’ facility. As part of the
system startup phase, step drawdown aquifer tests were conducted for two newly installed extraction wells and
a 72-hour constant rate aquifer test was conducted that included monitoring of 19 monitoring wells. Section
2.1.1 summarizes the hydrogeology in the area of tests and brief summaries of the aquifer tests are provided in
Sections 2.1.2 and 2.1.3. Section 2.1.4 presents an assessment of the tests compared to industry standards
and if the data reported can be used to provide a better understanding of the Lower Tuscan Formation aquifer
system’s hydraulic performance.
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Figure 2-1. Site Location Map of Former Koppers Company Facility and
Off-Property Groundwater Extraction System
2.1.1 Hydrogeology
The hydrogeology for the project was developed by Blair and others (1991). In this paper and for the purposes
of the remedial investigation conducted as part of the Superfund process, the numerous geologic formations
identified in the area were condensed into four units. These units include (from oldest to youngest) the Ione,
Tuscan [identified as Mehrten Formation in Blair and others (1991) and Dames and Moore (1993) report],
Nomlaki Tuff, and Laguna Formations. In the Oroville area, the Nomlaki Tuff is designated as a member of the
Laguna Formation (Busacca, 1982) whereas north of Oroville in the area of the LTA project is designated as part
of the Tuscan Formation. The Nomlaki Tuff was isolated as a formal formation for the Koppers Superfund
project due to its color, composition, and thickness that made it easily distinguishable in drilling samples from
the Laguna and Tuscan Formations. The presence of the Nomlaki Tuff also indicates that the Tuscan Formation
in this area is part of the LTA (Brown and Caldwell, 2010). The identification as the LTA in this area is further
supported by the presence of metamorphic clasts within the Tuscan Formation of this area as described by Blair
and others (1991).
The conceptual hydrogeologic model developed for the site identifies several paleo-valleys formed by the
ancestral migration of the Feather River throughout the area. These paleo-valleys juxtapose units of the geologic
formations discussed above whereby groundwater aquifers are connected laterally within these areas. These
relationships are illustrated in Figure 20 of the Dames and Moore (1993) report that is reproduced below on
Figure 2-2.
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Figure 2-2. llustrating Hydrogeologic Conceptual Model Developed for Project. An example of a paleo-valley is shown at the top of diagram
between RI-7/13 and RI-10.
Figure 20 from Dames and Moore (1993)
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2.1.2 Step Drawdown Aquifer Tests
Step drawdown aquifer tests were conducted in each of the two extraction wells, designated EW-3 and EW-4,
installed for the system. The locations of these wells are shown on Figure 2-3 reproduced from the Dames and
Moore (1993) report. Figure 18 from the report (reproduced as Figure 2-4 in this report) presents a generalized
geologic cross section that shows the two extraction wells are completed in the Tuscan Formation (referred to as
Mehrten Formation in Report). As discussed in Section 2.1.1, the Tuscan Formation in this area is part of the
LTA. The approximate thickness of the LTA as measured on Figure 2-3 is 160 feet. A copy of the geologic
summary log produced for the two extraction wells is provided in Appendix A. Table 11 from the Dames and
Moore (1993) report providing well construction details for these wells along with monitoring wells used for the
constant rate aquifer test discussed in Section 2.1.3 is reproduced as Table 2-1.
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Figure 2-3. Well Location Map for Extraction Well Aquifer Test
Reproduced from Dames and Moore (1993)
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Figure 2-4. Generalized Hydrogeologic Cross Section Showing Construction Details of
Extraction Wells Used for Aquifer Test
Figure 18 from Dames and Moore (1993).
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Table 2-1. Well construction details for wells used during aquifer testing.
Reproduced from Dames and Moore (1993).
Distance From
Pumping Well
(feet)1
Well Casing
Diameter
(inches)
Screened Interval
(feet bgs)
Pump Depth
(feet bgs)
Monitoring
During Test2
P-2
1980
5
148.5-168.5
-
M
RI-8
2520
5
167-197
-
M
RI-9
1360
5
161-191
-
D,M
RI-10
1325
5
133-163
-
D,M
RI-11
2120
8
150-186
-
M
RI-12
2180
8
215-255
-
M
RI-15
1530
5
178.5-185.5
-
M
RI-16A
944
5
72-92
-
D,M
RI-16B
956
5
148.5-168.5
-
D,M
RI-16C
929
5
178-198
-
D,M
RI-16D
943
5
230-250
-
D,M
RI-17A
1553
5
94.5-114.5
-
D,M
RI-17B
1584
5
136.5-156.5
-
D,M
RI-17C
1589
5
192.5-212.5
-
D,M
RI-17D
1578
5
236.5-256.5
-
D,M
RI-18A
672
5
124-139
-
D,M
RI-18B
694
5
165-185
-
D,M
RI-19A
896
5
110.5-125.5
-
D,M
RI-19B
880
5
160.5-180.5
-
D,M
EW-3
-
10
101-201
90
D,M
EW-4
-
10
99.5-199.5
90
D,M
Well No.
1.
Distance from center point between pumping wells EW-3 and EW-4
2.
D – datalogger; M - Manual
The step drawdown tests were conducted on February 5 (EW-3) and 8 (EW-4), 1993 and consisted of pumping
each well at 200 gallons per minute (gpm), 300 gpm, and 400 gpm for a minimum of 30 minutes at each rate.
The wells were not allowed to recover between each step. Using these data, well losses were estimated using
the method described by Sheahan (1971) and found to be minimal. The test concluded that the design
pumping rate of 300 gpm for the remedial action was feasible within each well. The specific capacity of the
wells measured during these tests ranged from 50 to 100 gpm per foot of drawdown.
2.1.3 Constant Rate Pumping Test
A constant rate pumping test was conducted for approximately 72 hours between April 20, 1993 and April 23,
1993 that consisted of pumping both extraction wells EW-3 and EW-4 at 300 gpm. The purpose of this test was
to monitor the aquifer’s response to pumping and to use the data to estimate aquifer parameters such as T, S,
effective radius (Ro), and capture zone dimensions of the remedial action. Prior to initiating the test, the
extractions wells were shut down to allow groundwater to approach static levels. Since the startup of the
extraction wells were part of the remedial action for the site, the wells were not shut off after completion of the
test and no recovery data was collected.
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In addition to the two extraction wells, water levels were monitored in 11 monitoring well sites as shown on
Figure 2-3. Four of these monitoring well sites consist of nested wells with screen intervals completed at various
depths throughout the aquifers (see Figure 2-2 and 2-4 for examples). Well construction details for each of
these wells are presented in Table 2-1. Water levels were measured using pressure transducers in the two
extraction wells and fourteen of the monitoring wells. Site barometric pressure readings were recorded
simultaneously by the datalogger. Based on review of barometric changes, correction of data was not required.
Three different techniques were used to analyze the pumping test data. For data analysis purposes, it was
assumed that the two pumping wells could be represented by a single pumping well located at the mid-point
between EW-3 and EW-4. For most of the observation well data, the Theis curve-matching method for a confined
aquifer was used to approximate T and S values. For extraction wells EW-3 and EW-4, the Jacob straight line
method was used to calculate T values. The straight line matches and calculations of T from this analysis are
reproduced in Figures 2-5 and 2-6. The distance versus drawdown method was also used to calculate T and S,
as well as the Ro using elapsed times of 100 minutes and 1,000 minutes as shown on Figures 2-7 (100
minutes) and 2-8 (1,000 minutes).
Figure 2-5. Time Drawdown Curve and Cooper-Jacob Straight Line Solution for Extraction Well EW-3
Reproduced from Dames and Moore (1993)
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Figure 2-6. Time Drawdown Curve and Cooper-Jacob Straight Line Solution for Extraction Well EW-4
Reproduced from Dames and Moore (1993)
Figure 2-7. Distance Drawdown Plot at Time Equals 100 Minutes
Reproduced from Dames and Moore (1993)
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Figure 2-8. Distance Drawdown Plot at Time Equals 1,000 Minutes
Reproduced from Dames and Moore (1993)
The Dames and Moore (1993) report states that drawdown data indicated that all monitoring wells monitored
for the test responded to pumping except for well RI-16A (Figure 2-3). As illustrated on Figure 2-4, this well is
completed within the Nomlaki Formation overlying the LTA in this area suggesting that the shallow aquifer zone
monitored by this well is not in hydraulic connection with the LTA. Review of the drawdown curve for this well
does suggest the well responded to pumping during later portions of the test possible indicating a leakage
response between the two aquifers. Estimates of T using the methods described above varied from 16,100
feet2 per day (ft2/day) to 26,300 ft2/day with an average of 20,140 ft2/day and values of S varied 0.0002 to
0.00044 with an average value of 0.00028. The Ro using the distance versus drawdown method was
approximately 3,000 feet after 100 minutes of pumping and 4,000 feet after 1,000 minutes of pumping.
Inspection of the drawdown curves indicates that after 1,000 minutes of pumping, drawdowns appear to be
reaching equilibrium.
Using the capture zone equations presented by McWhorter and Sunada (1977) and Javandel and Tsang (1986),
estimates of the capture zone width and stagnation point for a confined aquifer after reaching equilibrium were
calculated. The equation is:
Ymax = Q/Ti
Where Ymax is the maximum width of the capture zone far upgradient of the pumping wells, Q is the pumping rate
and i is the hydraulic gradient. Capture zone width at the pumping well can be estimated using the relationship:
Ywell = Ymax/2
The stagnation point X, the downgradient location where the particle velocity caused by pumpage in the
extraction well equals the velocity imparted by regional flow, is calculated using the relationship:
X = Ywell/π
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These parameters were calculated using the following values obtained from the aquifer test:
Q = 600 gpm
T= 20,140 ft2/day
i = 0.001
Using these values Ymax is 5,375 feet, Ywell is 2,878 feet, and X is 913 feet.
2.1.4 Usability of Data
Software packages such as AQTESOLV™ were not available in 1993 when this aquifer test was conducted and
curve matching was conducted by visual assessments. As such, the drawdown curves produced for this project
were only evaluated using the Theis (1935) solution for unsteady flow to a fully penetrating well in a confined
aquifer that assumes a line source for the pumping well and therefore ignores wellbore storage. This solution
also does not account for leakage through an aquitard. The conceptual model developed for this site is very
similar to the conceptual model developed for the aquifer test conducted at the Esquon Ranch (Section 3.3)
whereby the LTA monitored for the aquifer test is not in hydraulic connection with a shallow aquifer and leakage
occurs through the aquitards. Using the Theis (1935) solution for drawdown curves produced from monitoring
wells during the Esquon Ranch, the T values were between 23,800 ft2/day to 20,900 ft2/day consistent with the
average value of 20,140 ft2/day calculated for this test. However, as discussed in Section 3.3, the more
appropriate solution to use based on the conceptual model is Moench (1985). This method can be used to
assume that a constant-head source aquifer supplies leakage across overlying and/or underlying aquitards that
is consistent with observation of wells completed in different aquifers during the Esquon aquifer tests. The
curve fits using this solution for the Esquon tests provided very good fits and the T values calculated were
between 6,653 ft2/day and 8,088 ft2/day. Similar T values would be expected for the Koppers’ aquifer test if
the Moench (1985) solution was used for these data although values calculated from the Theis solution are
within the same order of magnitude and would not significantly affect the results of groundwater models
developed from these data. The average S value of 0.00028 calculated for the Koppers’ test is also consistent
with the values calculated for the Esquon Ranch where the average S value is 0.00034. The capture zone
analysis provided from this testing can be used to provided initial assessments of the zone of influence
(distance from pumping well) that would be affected by pumping of a well at specific pumping rate
Of more significant importance from this test was the development of the site conceptual hydrogeologic model.
This detailed model was developed from lithologic samples collected continuously during drilling that were used
to produce detailed geologic boring logs that included the identification of formation boundary’s, relative
differences in water production between zones, and vertical differences in water quality. The methods of Blair
and others (1991) used for the LTA project for developing the criteria for identifying formation boundaries from
lithologic samples collected during the drilling of monitoring wells (Brown and Caldwell, 2010) is based on the
data collected from the Kopper’s project. As illustrated on Figure 2-2, this detailed analysis showed that
deposition of materials from the ancestral migration of the Feather River formed large paleo-valleys where
aquifer materials of the LTA are juxtaposed against aquifer zones developed within other units. This
juxtaposition results in groundwater flowing laterally from one aquifer unit (Laguna Formation) to other aquifer
units (LTA and/or Ione). This type of lateral flow between the LTA aquifer unit and other formations is further
illustrated below on Figure 2-9 reproduced from Blair and others (1991). The arrows presented on the figure
represent the movement of groundwater and show the lateral movement between aquifer units (as indicated in
Section 2.1.1, Blair and others (1991) refer to the LTA as the Mehrten Formation).
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Figure 2-9. Arrows presented on cross section represent the direction of groundwater flow and illustrate the lateral
movement of groundwater between the different aquifer formations. Lower Tuscan Formation designated as Mehrten
Formation in report.
Figure 9a from Blair and Others (1991).
It is anticipated that this type of relationship exists throughout the LTA and future studies should focus on
developing the data to assess these conditions throughout the basin.
Based on review of the data presented in the above sections, the aquifer tests conducted for this project were
performed in accordance with industry standards of the time and the data reported can be used to provide a
better understanding of the Lower Tuscan Formation aquifer system’s hydraulic performance.
2.2 1996 M&T Chico Ranch Aquifer Test
The results of the aquifer test conducted for this project are presented in a memorandum prepared by the DWR
in December 1996 entitled M&T Chico Ranch Conjunctive Use Investigation, Phase III (DWR, 1996). The M&T
Chico Ranch is located in western Butte County and consists of about 8,300 acres, bordered by the Sacramento
River to the west, Big Chico Creek to the north, and Ord Ferry Road to the south. This ranch is also the location
of one of the aquifer tests conducted for the LTA project as discussed in Section 3.3. Figure 2-10 shows the
location of the well used for the test discussed in this section as well as the pumping well used for the LTA
project.
The report presents results of aquifer tests conducted in June 1995 and May 1996. The June 1995 aquifer test
was conducted in a then recently installed production well completed within the LTA. The primary objective of
this aquifer test was to assess the aquifer performance of the LTA in this area and the production/efficiency of
the newly installed well. Aquifer testing consisted of step-drawdown tests and a 45 hour constant rate aquifer
test. A secondary purpose of the constant rate aquifer test was to assess possible interconnection between
shallow and deep aquifer zones and included recording drawdown in seven surrounding monitoring wells. A
pumping rate of 1,650 gpm was used for the constant rate test.
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Figure 2-10. Location of Pumping Well used for LTA Project (PW-MT-1) and the DWR M&T Aquifer Test (PW-MT-4)
Findings from the June 1995 test concluded that there was reduced well efficiency of the newly installed well
due to inadequate well development or less than optimum gravel pack size. Based on these findings, a new
pump was installed within the production well and the well was redeveloped in April 1996. After development,
the May 1996 aquifer test was conducted that consisted of a step-drawdown test on the production well and a
30 hour constant rate aquifer test. The constant rate aquifer test consisted of pumping the production well at
3,000 gpm and recording drawdown in five surrounding monitoring wells.
Section 2.2.1 summarizes the hydrogeology in the area of tests and brief summaries of the aquifer tests are
provided in Sections 2.2.2 and 2.2.3. Section 2.2.4 presents an assessment of the tests compared to industry
standards and if the data reported can be used to provide a better understanding of the Lower Tuscan
Formation aquifer system’s hydraulic performance.
2.2.1 Hydrogeology
The DWR (1996) report states that earlier reports identified a laterally extensive and potentially productive
water-bearing zone beneath the M&T Chico Ranch within the “lower-confined” Tuscan Formation aquifer. Based
on screen intervals completed for this project, this aquifer occurs between approximately 730 feet bgs to 1,000
feet bgs. The DWR (1996) report indicated that earlier data collected by DWR in 1993 ed showed that the
deeper aquifer system is overlain by significant low permeability units (clay units) that separate this aquifer from
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shallower aquifers within both the Tuscan Formation and younger formations whereby drawdown (lowering of
water levels) would be minimized in the shallow systems from pumping in the deeper aquifer. As discussed in
Section 4.3.1 and illustrated on Figure 4-10, the occurrence of this deeper aquifer at the approximate depths
stated was confirmed during the drilling of the groundwater monitoring well completed for the LTA project on the
M&T Ranch. Figure 4-10 also shows shallower aquifers within the upper Tuscan Aquifer (350 feet bgs to 400
feet bgs) and younger Quarternary Deposits (20 feet bgs to 100 feet bgs).
2.2.2 June 1995 Aquifer Testing
For this aquifer test, a 1,018 foot monitoring well, designated 24B01, and 950 foot test production well,
designated 24B02, were installed. Production well 24B02 was also monitored for the aquifer test conducted for
the LTA project at the M&T Ranch and was designated PW-MT-4 (Section 3.2). The monitoring well is screened
from 820 to 840 feet bgs whereas the production well is screened from 760 to 920 feet bgs. Aquifer tests
included performance of a step-drawdown test and constant rate test. During these tests, groundwater level
measurements were collected using a steel tape and electronic sounder. Pumping rates were determined with
an ultrasound flow meter and adjusted using partially-full-pipe calculations.
The step-drawdown test consisted of pumping well 25B02 for three one-hour steps at incrementally increasing
pumping rates of 800 gpm, 1,300 gpm, and 1,740 gpm. During this pumping, drawdown was recorded in the
pumping well as well as monitoring well 24B01. The primary purpose of the step drawdown test was to provide
the information necessary for design of an appropriate constant-discharge aquifer test but also provided
preliminary estimates of aquifer transmissivity. Figure 3 from this report presented the drawdown curves within
the pumping well for this test and the estimated specific capacities and is reproduced below in Figure 2-11.
Using the Theis recovery method, a preliminary estimate of the T for this aquifer was 8,020 ft2/day.
Figure 2-11. Time Drawdown Plot for 1995 Step Drawdown Test
Reproduced from DWR (1996)
The constant rate aquifer test started on June 14, 1995 and continued for approximately 45 hours. Based on
the results of the step-drawdown test, the pumping rate for the test production well 24B02 was set at 1,650
gpm. As stated in the DWR (1996) report, the objective of this aquifer test was to provide more accurate
estimates of aquifer T and S and to examine possible interconnections between the deeper aquifer and shallow
aquifers. During the test, drawdown was recorded in the pumping well and seven surrounding observation wells.
For the pumping well and the newly installed monitoring well 24B01, drawdown was recorded frequently during
the test. For the remaining six observation wells, drawdown measurements were only recorded at approximately
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6, 23, and 44 hours after startup of the test. Observation wells ranged from 191 feet to 8,200 feet from the
pumping well as shown on Figure 7 of the DWR (1996) report reproduced below as Figure 2-12. With the
exception of the newly installed monitoring well 24B01, the observation wells were screened within shallower
zones than the pumped well with total depths ranging from 54 feet bgs (well 23J01 approximately 5,800 feet
from pumping well) to 640 feet bgs (well 07l01 approximately 7,300 feet from pumping well).
Figure 2-12. Location Map Showing Location of Wells Monitored during 1995 Aquifer Test
Figure 7 from DWR (1996).
Aquifer analysis was conducted using the software package AQTESOLV™ and the drawdown data from
observation well 24B01. AQTESOLV™ is the same package used for analysis of aquifer tests conducted for the
LTA project as discussed in Section 3. Solutions used for analysis included the confined aquifer solutions of
Theis and Cooper-Jacobs and the leaky confined aquifer solution of Moench. From this analysis T values ranged
from 9,940 ft2/day (Moench solution) to 10,329 ft2/day (Theis solution) and S values ranged from 0.00008
(Moench solution) to 0.00027 (Cooper-Jacobs).
The DWR (1996) report indicated that the drawdown curve for the pumping well appeared characteristic of a
well pumping from a leaky aquifer or from a well intersecting a recharge source. In addition, this report states
that based on response from observation wells completed within shallower aquifers that there is no apparent
connection with these zones and the deeper aquifer where pumping occurred. The DWR (1996) report also
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concluded that the pumping well efficiency was low and that additional well development should be conducted
and another aquifer test conducted at higher pumping rates.
2.2.3 May 1996 Aquifer Testing
Based on the recommendations from the June 1995 aquifer test, the production well used for this test was
redeveloped on April 29, 1996. Based on estimated specific capacity during this development, DWR concluded
that the initial well development in 1995 was probably adequate. After well development, another stepdrawdown test was conducted that consisted of pumping the production well for three one-hour steps at
successive rates of 1,250 gpm, 2,050 gpm, and 3,000 gpm. Using the Theis recovery formula, the estimated T
for this test was 7,085 ft2/day. Using this information, a 30-hour constant rate test was started on May 6, 1996.
This test consisted of pumping the production well 24B02 at a constant rate of 3,000 gpm and recording
drawdown in five surrounding monitoring wells including the test well installed for the June 1995 test, 24B01
(see Figure 2-12 for locations).
Figure 2-13 reproduces the drawdown graph for monitoring well 24B01 and shows that the total drawdown in
this well was approximately 43 feet with 80 percent recovery two hours after shutdown of the production well.
As with the June 1995 aquifer test, observation well 13H01 (completed less than 100 feet bgs) located about
2,700 feet northeast of pumping well, showed no changes in water levels during the aquifer test. Response to
pumping from the other three observation wells could not be assessed because observation well 23J01 began
pumping two hours into the test.
Figure 2-13. Time Drawdown Graph for Monitoring Well 24B01 During 1996 Constant-Discharge Aquifer Test
Reproduced from DWR (1996)
As with the previous aquifer test, aquifer analysis was conducted using the software package AQTESOLV™ and
the drawdown data from observation well 24B01. Solutions used for analysis included the confined aquifer
solutions of Theis and Cooper-Jacobs and the leaky confined aquifer solution of Moench. An independent hand
analysis not using the AQTESOLV™ software was also conducted using the Cooper-Jacob straight line solution.
From this analysis T values ranged from 9,213 ft2/day (Moench solution) to 10,055 ft2/day (Cooper-Jacobs hand
solution) and S values ranged from 0.000096 (Cooper Jacobs hand solution) to 0.000027 (all other solutions).
These values are consistent with the June 1995 aquifer test. DWR also concluded that the time-drawdown data
was more characteristic of a confined aquifer rather than a leaky confined aquifer.
DWR assessed two proposed production well designs to assess potential drawdown related impacts to
surrounding groundwater users near the M&T Ranch. The two proposed well designs included a composite well
screened within both the intermediate aquifer zone and deep aquifer zone (300 to 900 feet bgs) and a well
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screened only within the deep aquifer zone (760 to 920 feet bgs). The analysis was conducted using the aquifer
parameters calculated during the May 1996 aquifer tests and the computer software package WTAQ2 (Barlow
and Moench, 2011). WTAQ2 simulates axial-symmetric flow to a well pumping from a confined or unconfined
(water-table) aquifer and calculates dimensionless or dimensional drawdowns.
For the deep aquifer zone, a T value of 10,026 ft2/day and specific capacity of 23 gallons per minute per foot
(gpm/ft) were used for the analysis. For the composite well, a T value of 16,710 ft2/day and specific capacity of
30 gpm/ft were used. DWR also stated that they calculated drawdowns assuming a water-table system
throughout even though the proposed production wells would be completed within confined aquifers. This
approach was taken because sufficient stress within the confined system could result in groundwater drawdown
within the unconfined aquifer. The results of this analysis are reproduced in Table 2-2 and assumed continuous
pumping for 90 days.
Table 2-2. Summary of DWR WTAQ2 Analysis for Potential Drawdown Impacts Related to
Operation of Proposed Production Wells
Reproduced from DWR (1996).
2.2.4 Usability of Data
As discussed in the introduction to Section 2.2, the production well (240B2) used for this aquifer test was
monitored as part of the aquifer test conducted for the LTA project. For the LTA project this well was labeled PW4 (Section 3.2). The production well used for the LTA project is screened within the intermediate aquifer
(approximately 340 to 390 feet bgs) described in the DWR (1996) report as opposed to the deep aquifer (760 to
920 feet bgs) screened by the production well used for the DWR aquifer test. Only one well appeared to be
screened within the intermediate aquifer zone (well 07L01, Figure 2-14) for the DWR test but was located over
1-mile from the production well and showed no response to pumping. Based on this data, the DWR concluded
that there was no hydraulic connection between the two aquifers but did suggest that at higher pumping rates
and longer sustained pumping, there could be a connection. For the May 1995 aquifer test, the DWR stated
that the drawdown curve for the pumping well appeared characteristic of a well pumping from a leaky aquifer or
from a well intersecting a recharge source.
As part of the LTA aquifer test, monitoring wells were placed within the intermediate aquifer zone, aquitard
material between the intermediate aquifer and deep aquifer (screened from 570 to 590 feet bgs), and within
the deep aquifer zone. As discussed in Section 3.2, the results of the LTA aquifer test clearly showed a hydraulic
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connection between the intermediate and deep aquifer zones with significant leakage occurring through the
aquitard.
To further assess the results of the DWR (1996) aquifer tests, reported water level data from the May 1996 test
was entered into the current version of AQTESOLV™ and analyzed following the procedures used for the LTA
project (Section 4). This analysis uses a series of diagnostic flow plots that aid in selecting the appropriate
aquifer solutions methods for assessing the aquifer test data. The detailed analysis using these plots for the
DWR May 1996 aquifer test is presented in Appendix B and summarized below.
As stated in the AQTESOLV™ User Manual (2007), derivative analysis is an invaluable tool for diagnosing a
number of distinct flow regimes. Examples of flow regimes that one may discern with derivative analysis include
infinite-acting radial flow, wellbore storage, linear flow, bilinear flow, inter-porosity flow and boundaries. The
derivative analysis of well 24B01 for the DWR May 1996 test is presented on Figure 2-14. Areas where the
derivative plot reaches a plateau indicate infinite acting radial flow and are portions of the drawdown curve
appropriate for the Cooper-Jacob straight line method to calculate transmissivity and storativity values of the
aquifer. As seen on Figure 2-14, a plateau of the derivative plot occurs between about 5 minutes and 20
minutes after startup of pumping. Figure 2-15 shows estimates of T and S using the Cooper-Jacob straight line
method over this portion of the curve.
DWR Test
2
10
Obs. Wells
Displacement (ft)
24B01
1
10
0
10
-1
10
0
10
1
2
10
10
3
10
10
4
Time (min)
Figure 2-14. Derivative (Blue) and Drawdown Curves (Red) for Well 24B01 during May 1996 DWR Aquifer Test
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Section 2
DWR Test
40.
Obs. Wells
24B01
Aquifer Model
Confined
32.
Solution
Cooper-Jacob
Displacement (ft)
Parameters
T = 7138.2 ft2/day
S = 0.0002178
24.
16.
8.
0.
10
-1
0
10
1
2
10
10
3
10
10
4
Adjusted Time (min)
Figure 2-15. Cooper Jacob Straight Solution for Well 24B01 during May 1996 DWR Aquifer Test
As seen on Figure 2-15 the estimated T and S values for this test are 7,138 ft2/day and 0.00022, respectively.
DWR’s estimate T and S values using the Cooper-Jacob solution was 9,960 ft2/day and 0.000027, respectively.
The shape of the derivative curve can also be used to interpret flow regions. As shown on Figure 2-14, after the
plateau discussed above, the derivative curve appears to start plunging toward zero. This behavior represents a
single infinite recharge (constant-head) boundary or a leaky confined aquifer with an incompressible aquitard
and constant-head source aquifer. Both of these interpretations are consistent with the interpretations
suggested by DWR during the June 1995 test and the LTA aquifer test conducted within the intermediate
aquifer.
Based on the derivative analysis discussed above, the Moench (1985) solution was selected for analysis of the
drawdown curve. This is the same method selected by DWR for the May 1996 aquifer test that provides a
solution for unsteady flow to a fully penetrating, finite-diameter well with wellbore storage and wellbore skin in a
homogeneous, isotropic leaky confined aquifer. In AQTESOLVE, there are three configurations for simulating a
leaky confined aquifer with aquitard storage for this method as follows:

Case 1 assumes constant-head source aquifers supply leakage across overlying and underlying aquitards.

Case 2 replaces both constant-head boundaries in Case 1 with no-flow boundaries

Case 3 replaces the underlying constant-head boundary in Case 1 with a no-flow boundary.
The Case 3 scenario was selected for analysis of the May 1996 test and is presented on Figure 2-16.
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DWR Test
2
10
Obs. Wells
24B01
Aquifer Model
Leaky
Solution
Moench (Case 3)
Displacement (ft)
Parameters
T =
S =
r/B' =
ß' =
r/B" =
ß" =
Sw =
r(w) =
r(c) =
1
10
5817.1 ft2/day
0.0001826
0.1073
0.05872
0.
0.
0.
1.167 ft
0.6667 ft
0
10
-1
10
0
10
10
1
2
10
3
10
4
10
Time (min)
Figure 2-16. Moench (1985) solution for well 24B01 during May 1996 aquifer test. Curve fits for drawdown (red) and
derivative plot (green) area shown in blue.
As seen on this figure, very good curve fits (blue lines) were obtained for both the drawdown curve and derivative
plot indicating that this was an appropriate solution for the test. T and S values calculated using this solution
are 5,817 ft2/day and 0.00018, respectively. Using this same solution, DWR calculated T and S values of 9,213
ft2/day and 0.000027, respectively. Using the more detailed analysis of data as conducted for the LTA project,
the T and S values calculated for this report are believed to be more accurate.
Neuman and Witherspoon (1969) derived a solution for unsteady flow to a fully penetrating well in a confined
two-aquifer system. The solution assumes a line source for the pumped well and therefore neglects wellbore
storage. This method allowed an assessment of calculated T and S values within the intermediate aquifer zone
and K values for the aquitard. Figure 2-17 presents the results of this analysis for well 24B01.
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Section 2
DWR Test
2
10
Obs. Wells
24B01
Aquifer Model
Leaky
Solution
Neuman-Witherspoon
Displacement (ft)
Parameters
T =
S =
r/B =
ß =
T2 =
S2 =
1
10
5194.2 ft2/day
0.000214
0.1936
0.07165
2.125E+4 ft2/day
1.0E-5
0
10
10
-1
10
0
1
2
10
10
3
10
4
10
Time (min)
Figure 2-17. Neuman-Witherspoon (1969) solution for well 24B01 during May 1996 aquifer test.
Curve fits for drawdown (red) and derivative plot (green) area shown in blue.
As seen on this figure, the T and S values calculated for the deep aquifer using this solution are consistent with
those calculated using the Moench (1985) solution. For the intermediate aquifer, this solution calculated a T
value (T2 on Figure 2-17) of 21,125 ft2/day and an S value of 0.00001. During the LTA project, the calculated T
and S values for the intermediate aquifer using the Moench (1985) solution ranged from 11,550 ft2/day to
20,680 ft2/day and 0.00045 to 0.0003, respectively. As seen by these results, T values from the LTA project
and analysis of the DWR (1996) results are relatively comparable for the intermediate aquifer zone. The K value
calculated for the aquitard between the two aquifers is 1.531 ft/day (Appendix A).
Based on review of the data presented in the above sections, the aquifer tests conducted for this project were
performed in accordance with industry standards of the time and the data reported can be used to provide a
better understanding of the Lower Tuscan Formation aquifer system’s hydraulic performance.
2.3 March 2009 Glenn-Colusa Irrigation District Test-Production Well
Installation and Aquifer Testing
In 2005, the Glenn-Colusa Irrigation District (GCID) began a three year project that included the installation of a
test production well, quadruple-completion observation well, and performance of constant rate aquifer test. The
purpose of the project was to further characterize the lower aquifer system in the area and provide
recommendations for future investigations. The results of this project are presented in a March 2009 report
prepared by DWR entitled Glenn-Colusa Irrigation District Test-Production Well Installation and Aquifer Testing
(DWR, 2009). Figure 1 from this report, reproduced as Figure 2-18, shows the location of these wells
completed near County Road 203 in Glenn County.
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Figure 2-18. Location Map for GCID Test Production Well and Observation Well
Figure 1 from DWR (2009)
Aquifer testing included a 12-hour step-drawdown test, a 24-hour constant rate aquifer test, and a 28-day
constant rate aquifer test. Flow rates for these tests ranged from 1,500 gpm to 6,000 gpm.
Section 2.3.1 summarizes the hydrogeology in the area of tests and brief summaries of the aquifer tests are
provided in Sections 2.3.2 and 2.3.3. Section 2.3.4 presents an assessment of the tests compared to industry
standards and if the data reported can be used to provide a better understanding of the Lower Tuscan
Formation aquifer system’s hydraulic performance.
2.3.1 Hydrogeology
The geologic borehole logs produced for this project are reproduced in Appendix B. As shown on these logs,
three main aquifer-bearing geologic formations were logged by DWR in the test-production and observation well
boreholes: the Tuscan Formation, Tehama Formation, and Stony Creek Fan alluvium. Figure 2-19, reproduced
from DWR (2009) shows the surface and approximate subsurface extent of these formations in the Sacramento
Valley.
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Figure 2-19. Surface and Subsurface Extent of Tuscan, Tehama, and Stony Creek Fan Alluvium
Reproduced from DWR (2009)
DWR (2009) also states that the fresh-to-brackish Upper Princeton Valley fill underlies the Tuscan and Tehama
Formations in the study area. However, as discussed in Section 4.1, as defined by Redwine (1972), the
Princeton Submarine Valley System is a morphological feature of the ancestral Sacramento River Basin and
contains the geologic formations described within the Sacramento Valley. For example, the Ione Formation is
used by Redwine to separate the lower and upper Princeton Valley fills and the Lovejoy Basalt is interpreted to
represent the rimrock of the upper Princeton Valley Fill.
As shown on the geologic well logs (Appendix B) and summarized on Table 2-3, the test production well is
completed within the Tuscan Formation and quadruple-completed observation wells has screen intervals within
the Stony Creek Fan, Tehama Formation, and Tuscan Formation.
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Table 2-3. Well Construction Details for Newly Installed Test Production and Nested Observation Well
State Well I.D.
Well Diameter
(inches)
Screen Interval
(feet bgs)
Geologic Formation
Test Production Well
22N02WO2JOO1M
20
800-820, 840-870,
900-1,240, 1,270-1,300
Tuscan
Observation Well
22N02W01N004M
2.5
71-81
Stony Creek Fan
Observation Well
22N02W01N003M
2.5
209-219, 358-368
Tehama
Observation Well
22N02W01N002M
2.5
699-709
Tehama/Tuscan
Observation Well
22N02W01N001M
2.5
813-823, 1040 to 1050
Tuscan
Well
Other wells used for the 28-day constant rate aquifer test are screened in one or more of these formations as
discussed in Section 2.3.3.
2.3.2 Step Drawdown and 24-Hour Constant Rate Aquifer Tests
A step drawdown aquifer test was conducted in newly installed test production well during December 2005. As
discussed above, the well is completed within the Tuscan Formation with an approximate thickness of 500 feet
(see geologic well log, Appendix B). The step drawdown tests consisted of pumping the well successive rates of
1,500 gpm, 3,000 gpm, 4,000 gpm, 5,000 gpm, and 6,000 gpm for intervals between 100 and 150 minutes.
The well was not allowed to recover between each step.
Within 24-hours after completion and using the data generated from the step test, a 24-hour constant rate
aquifer test was conducted at a pumping rate of 5,000 gpm. Because the nearby nested observation well
(N001M through N004M) had not yet been installed, groundwater levels were only measured in the test
production well during these tests. The primary objective of the step drawdown and 24-hour constant rate
aquifer tests was to determine the highest flow rate at which the test production well could operate efficiently
during the 28-day constant rate aquifer test.
Time versus drawdown plots for the step drawdown and 24-hour constant rate tests are shown on Figures 2-20
and 2-21, respectively. Specific capacities measured during the step drawdown test ranged from 27.2 gpm per
foot of drawdown (6,000 gpm) to 33.6 gpm per foot of drawdown (1,500 gpm). Using the Jacob Straight Line
method, DWR (2009) calculated a T of 5,437 ft2/day from the 24-hour constant discharge test (solution shown
on Figure 2-22). The calculated hydraulic conductivity (K) value based on an aquifer thickness of 480 feet is
11.14 ft/day typical for silty to clean sands (Table 1-1).
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Section 2
Figure 2-20. Time Drawdown Plot for 12-Hour Step-Drawdown Aquifer Test
Reproduced from DWR (2009)
Figure 2-21. Time Drawdown Plot and Jacob Straight Line Solution for Test Production Well
During 24-Hour Constant-Discharge Aquifer Test
Reproduced from DWR (2009)
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2.3.3 28-Day Constant Rate Aquifer Test
The 28-day constant rate aquifer test was conducted between April 18, 2007 and May 16, 2007 that consisted
of pumping the test production well. Pumping started at approximately 3,000 gpm then was increased to 3,500
gpm one hour into the test due to cavitation problems at 3,000 gpm. The purpose of this test was to better
estimate the hydrogeologic properties of the deep aquifer system (Tuscan Formation), evaluate aquifer
interconnections, and identify possible aquifer boundary conditions. Groundwater levels during the test were
recorded in the test production well and 46 observation wells, including the 4 wells of the quadruple completion
well installed for the test. Many of the other observations are multi-completion observation wells similar in
construction to the quadruple completed observation well installed for this project.
Ten of the observation wells are completed within the Tuscan Aquifer system pumped by the production well.
Table 2-4 reproduced Table 5 from the DWR (2009) report summarizing well construction details and
approximate distance from the pumping well for each of these ten observations wells. Figure 2-22 shows the
location of the test well and 46 observation wells used for the test.
Table 2-4. Well Construction details of test production and observation wells used
for 28-day constant discharge test. Reproduced Table 5 from DWR (2009).
Figure 2-22. Location of Test Production and
Observations Well For 28-Day Constant Rate
Test
Reproduced from DWR (2009)
Groundwater levels in the test well were measured at 1-minute intervals until two days after shutdown of the
pumping well (May 18, 2007) at which time water levels were recorded every 10 minutes until May 30, 2007.
Groundwater levels within the observation wells were recorded hourly throughout the testing. Groundwater
levels were recorded using pressure transducers equipped within each of the wells and periodically using a hand
held water level sounder. The report did not indicate if vented pressure transducers were used or if the data
was corrected using barometric data.
T and S values were calculated using the Jacob straight line method for time-drawdown data for the test
production well and newly installed deep observation well (01N001M, Table 2-4) and the distance drawdown
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Section 2
method. The time drawdown plot for the newly installed deep observation well and the distance drawdown plot
presented in the DWR (2009) report are shown on Figures 2-23 and 2-24.
Figure 2-23. Jacob Straight Line Method Using Time Drawdown Data from 28-Day Constant Rate Aquifer Test for Newly
Installed Deep Observation Well (N001M)
Reproduced from DWR (2009)
Figure 2-24. Distance Drawdown Plot at 40,000 Minutes for 28-Day Constant Rate Aquifer Test
Reproduced from DWR (2009)
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T values from these two methods ranged from 3,984 ft2/day to 4,259 ft2/day and S values ranged from 0.0004
to 0.00007. The T value calculated using the time drawdown data from the test production well was 4,941
ft2/day. Using an aquifer thickness of 480 feet, K values range from 8.3 ft/day to 10.3 ft/day consistent with
the silty to clean sands logged during installation of the test production and observation well.
To assess the radius of influence from pumping the test production well, DWR (2009) used two methods:
observing measured drawdown within observation wells; and, by estimating radius of influence from the
distance drawdown plot shown on Figure 2-24. Using the first method, two wells screened within the pumped
aquifer showed response to pumping of the test well, 01N001M (deep well in new observation well) and
15C002M (Figure 2-22). Well 15C002M is located approximately 2.2 miles from the test production well. The
hydrograph from the next nearest observation well, 18C001M (4.8 miles from test production well), shows no
observable response to pumping indicating that the influence of pumping becomes negligible between 2.2 miles
and 4.8 miles. Using the second method illustrated on Figure 2-24, the estimated radius of influence is about 5
miles.
DWR (2009) also stated that the only well screened within aquifers shallower than the production well that
showed a response to both pumping and recovery from the 28-day constant rate aquifer test was the
intermediate deep well (01N002M) from the newly installed observation well. This well is screened
approximately 100 feet above the pumped aquifer from 699 feet bgs to 709 feet bgs. DWR (2009) indicated
that groundwater fluctuations within the remaining observation wells screened within shallower zones were due
to seasonal variations or pumping of nearby irrigation or domestic wells screened within these zones.
2.3.4 Usability of Data
Although the software package AQTESOLV™ was available in 2007 when this aquifer test was conducted, DWR
(2009) chose to analysis these tests using time drawdown graphs and the Jacob straight line method or
distance drawdown plots. In AQTESOLV™ these methods are used to obtain preliminary estimates of T and S
values for use in constraining the analysis of drawdown curves using other solutions. It should also be noted
that the two methods used are only valid for portions of the drawdown curve that indicate radial flow in an
infinite-acting confined aquifer. No analysis was conducted to confirm these assumptions such as could be
done with AQTESOLV™. As discussed in Section 2.2.4, use of the derivative analysis provided in the AQTESOLV™
software package would also have provided more insight into an appropriate conceptual hydrogeologic model for
the area. Based on the response to pumping from the intermediate deep well within the newly installed
observation well, a solution that assumes a leaky confined aquifer such as Moench (1985) would provide more
accurate values of T and S. However, the reported K values calculated from the reported T values are consistent
with the silty sand and clean sands observed during drilling of the test and observation wells.
The DWR (2009) also shows that influence to pumping at a rate of 3,500 gpm within the deep aquifer was only
observed at a distance of 2.2 miles from the test production well. No drawdown was observed in the next
closest well screened in the pumped aquifer located approximately 4.8 miles from the test production well. The
28-day constant rate test also suggests that there is only hydraulic connection with the aquifer zone just above
the deep aquifer zone. Other wells screened within shallower aquifer zones showed no response to pumping in
the deep aquifer.
Based on review of the data presented in the above sections, the aquifer tests conducted for this project were
performed in accordance with industry standards of the time and the data reported can be used to provide a
better understanding of the Lower Tuscan Formation aquifer system’s hydraulic performance.
2.4 October 2009 Aquifer Test Report: Orland Site
In 2009, Malcom Pirnie Inc. (Malcom Pirnie) performed an aquifer test using a test well constructed for the
Crystal Geyser Water Company (Crystal Geyser). The stated objectives of the aquifer test were to:
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

Section 2
Evaluate the physical and hydrogeologic characteristics of an unconsolidated, confined aquifer beneath the
Site and assess whether the long-term yield of the test well would meet the needs of the proposed project
Evaluate whether the use of the well would negatively impact the use of private domestic wells located near
the Site.
The aquifer test was conducted as part of an application by Crystal Geyser to build a beverage bottling plant in
the City of Orland, California.
The results of this project are presented in an October 2009 report prepared by Malcolm Pirnie entitled, ‘Aquifer
Test Report: Orland Site’ that is Attachment 5 to Crystal Geyser’s October 5, 2009 application to the City of
Orland entitled, ‘Application for Site Plan Review’ (Crystal Geyser, 2009). Figure 3-1 from the Malcom Pirnie
report, reproduced as Figure 2-25, shows the location of the test well completed near the intersection of County
Road 200E and the Tehama-Colusa Canal in Orland, California.
Figure 2-25. Location Map Showing Test Well and Observation Wells Used for Aquifer Test
Reproduced Figure 3-1 from Crystal Geyser (2009)
Aquifer testing included a step-drawdown test and a 9-day constant rate aquifer test. Flow rates for these tests
ranged from 200 gpm to 600 gpm.
Section 2.4.1 summarizes the hydrogeology in the area of tests and brief summaries of the aquifer tests are
provided in Sections 2.4.2 and 2.4.3. Section 2.4.4 presents an assessment of the tests compared to industry
standards and if the data reported can be used to provide a better understanding of the Lower Tuscan
Formation aquifer system’s hydraulic performance.
2.4.1 Hydrogeology
Figure 2-1 from the Malcolm Pirnie report, reproduced as Figure 2-26, shows a generalized geologic cross
section of the area and the screened depth of wells used for the aquifer test. As shown on this figure, two main
aquifer-bearing geologic formations were identified, the Stony Creek Fan alluvium and Tehama Formation. The
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Stony Creek Fan is identified as an unconfined aquifer. Underlying the Stony Creek Fan is the Tehama
Formation where the upper 100 feet of this unit consists of a clay unit that acts as a confining layer between the
Tehama upper aquifer system and the Stony Creek Fan aquifer system. Figure 2-26 also shows a 250 foot thick
confining layer beneath the confined aquifer of the Tehama Formation.
Figure 2-26. Conceptual Profile of Subsurface Site Conditions, Crystal Geyser Facility
Reproduced Figure 2-1 from Crystal Geyser (2009)
Figure 2-26 also shows that the test well (PW-1) and observation wells (MW-1S and MW-2) installed for the
project are completed within the confined aquifer system of the Tehama Formation. Other monitoring wells
monitored during the aquifer test are completed within the Tehama Formation confined aquifer, upper confining
unit of the Tehama Formation, and the Stony Creek Fan. As discussed in Section 2.4.3, MW-1 is a nested
observation well with screen zones in the Tehama Formation confined aquifer and two deeper screened zones.
The report or geologic well logs produced for the project do not indicate what geologic formations these wells are
completed.
2.4.2 Step-Drawdown Aquifer Test
A step-drawdown aquifer test for the test well was conducted on July 1, 2009 consisting of four two hour steps
pumping at rates of 200 gpm, 300 gpm, 400 gpm, and 500 gpm. A fifth 80 minute step was performed at a
rate of 600 gpm. During the aquifer test water levels were measured in the test well using a pressure
transducer programed to record water levels at intervals of 1-minute for the first 10 minutes of each step and
then every 5 minutes thereafter. The purpose of the step-drawdown test was to select the appropriate pumping
rate for the 9-day constant-discharge aquifer test.
The results of this aquifer test indicated that the test well could pump efficiently at any rate between 200 gpm
and 600 gpm. Figure 2-27 shows the time-drawdown curve produced for step-drawdown aquifer test and
includes the measured specific capacities. Specific capacities measured during the test ranged from 14 gpm/ft
to 22 gpm/ft. No aquifer parameters such as T and K were estimated from the results of this test.
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Figure 2-27. Time Drawdown Plot Produced During Step-Drawdown Aquifer Test for Crystal Geyser Aquifer Testing.
Inset of Figure Shows Specific Capacities Calculated from the Test
Reproduced from Crystal Geyser (2009)
2.4.3 9-Day Constant Rate Aquifer Test
The 9-day constant rate aquifer test was conducted between August 25, 2009 and September 3, 2009. Based
on the results of the step drawdown test, a pumping rate of 410 gpm was used for the test. During the test,
changes in groundwater levels were recorded using pressure transducers in the test well designated PW-1, two
observation wells located on site designated MW-1S and MW-2, and 11 irrigation and domestic wells located in
the area as shown on Figure 2-25. The approximate distance from the test well, well construction details, and
zone monitored for each well is summarized on Table 2-5. As noted on this table, observation well MW-1 is a
nested well with screen zones in the Tehama Formation aquifer pumped during the test (MW-1S) and two
deeper screen zones (MW-1M and MW-1D). Water levels in observation wells MW-1M and MW-1D were
recorded using hand measurements.
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Table 2-5. Well Construction Details for Test Well and Observation Wells
Distance from Test Well
(feet)
Screen Interval
(feet bgs)
Hydrostratigraphic Unit
0
135-175
Confined Aquifer
MW-1S
100
130-170
Confined Aquifer
MW-1M
100
290-340
>80 feet below Confined Aquifer
MW-1D
100
520-570
>300 feet below Confined Aquifer
MW-2
1000
140-150
Confined Aquifer
1450 E. South Street
353
6837 County Road 200
875
Not reported
Unconfined Aquifer/Upper Confining Unit
4280 County Road N
907
Not reported
Confined Aquifer
6838 County Road 18
920
Not reported
Unconfined Aquifer/Upper Confining Unit
4294 County Road N
1245
Not reported
Unconfined Aquifer/Upper Confining Unit
4300 County Road N
1294
Not reported
Unconfined Aquifer
4310 County Road N
1595
Not reported
Unconfined Aquifer
6800 County Road 19
1681
Not reported
Unconfined Aquifer/Upper Confining Unit
4317 Count Road N
1725
Not reported
Unconfined Aquifer/Upper Confining Unit
6815 County Road 15
2332
Not reported
Unconfined Aquifer/Upper Confining Unit
6825 County Road 15
2782
Not reported
Unconfined Aquifer/Upper Confining Unit
Well
Test Production Well
Unconfined Aquifer/Upper Confining Unit
The results of the aquifer test were analyzed using the Walton Leaky Artesian method and the Cooper-Jacob
distance drawdown method. Recovery data was analyzed using the Theis recovery method. The Walton’s Leaky
Artesian method was selected because comparison of the drawdown plots to the Theis curve showed that the
drawdown curves produced for the wells were below the Theis curve suggesting that the tested aquifer was
receiving recharge or leakage during the test. Table 2-6 summarizes the results of this analysis showing that T
values ranged from 3,075 ft2/day to 5,214 ft2/day and S values ranged from 0.001 to 0.0001. Assuming an
aquifer thickness of 40 feet based on the screen interval for the test well (report assumes test well is fully
penetrating), K values ranged from 77 ft/day to 130 ft/day typical of well sorted sands and consistent with the
material described on the MW-1 geologic boring log presented in the report.
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Table 2-6. Summary of Aquifer Test Analysis during 9-day Constant Rate Aquifer Test
T
(ft2/day)
Well I.D./Analysis Method
S
(unitless)
Walton’s Leaky Artesian
MW-1S
3,075
0.0006
MW-2
4,545
0.0001
Cooper-Jacob Distance Drawdown
t = 2,000 minutes
5,214
0.001
t = 7,300 minutes
5,214
0.0006
Theis Recovery
PW-1
3,877
NA
MW-1S
3,743
NA
MW-2
4,278
NA
The Malcom Pirnie report also states that based on the hydrographs produced for the 11 observation wells,
pumping of the test well in the confined aquifer of the Tehama Formation did not affect wells screened within
the upper confining layer of the Tehama Formation or the unconfined aquifer within the Stony Creek Fan.
Although the report indicates that water levels were recorded in the deeper screened intervals of observation
well MW-1, this data was not presented in the report. The report also does not indicate the geologic formation
these wells are completed in.
2.4.4 Usability of Data
Based on review of the data presented in the above sections, the aquifer tests conducted for this project were
performed in accordance with industry standards. However, neither the pumping well nor the observation wells
used for the test were completed within the Tuscan Formation. As such, the data reported for this test is not
usable for providing a better understanding of the Lower Tuscan Formation aquifer system’s hydraulic
performance.
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Section 3
Methods and Procedures for LTA
Aquifer Test and Analysis
Three separate aquifer performance tests were conducted as part of the LTA project using existing
production wells connected to irrigation distribution systems (Figure 1-1). The water extracted was used
as part of existing irrigation practices and distributed according to normal operating conditions at each
location. Prior to use, each location was reviewed and cleared as part of the Initial Study for the project
(Butte County, 2010). As discussed in the introduction, the purpose of the aquifer tests is to monitor the
LTA’s response to pumping, assess interaction with other aquifers, and to use the data to estimate
aquifer parameters.
A summary of the methods and procedures used to conduct each of the tests is presented in the
following sections. The aquifer tests were performed in accordance with American Society for Testing
and Materials Method D 4050 as modified in the Technical Memorandum Number 3 prepared for the
project (Brown and Caldwell, 2011). As stated in Section 1, the three aquifer tests are referred to as the
Hackett Property (north), M&T Ranch (central), and Esquon Ranch (south) aquifer tests.
3.1 Hackett Property Aquifer Test
Figure 3-1 shows a close-up of the aquifer test area conducted on the Hackett Property including the
location of the pumping well, primary observation wells, and other known irrigation supply wells. For this
aquifer test, the primary observation well was installed as part of the overall LTA project and is
designated MW-HP-1. Observation well MW-HP-1 is a nested well consisting of three separate screen
intervals within the same borehole. A detailed discussion of the installation of this well including
lithologic information obtained during drilling is presented in the Field Investigation Report (Brown and
Caldwell, 2012). The pumping well (Figure 3-1) used for this aquifer test is designated PW-HP-1. Well
construction details for the pumping well and primary observation wells are provided on Table 3-1.
3-1
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Figure 3-1. Hackett Property Aquifer Test Location Illustrating Monitoring Well and Pumping Well Locations
Table 3-1. Well Construction Details for Hackett Property Aquifer Test
Latitude
Longitude
Distance From
Pumping Well
(Feet)
Screen
Interval
(Feet bgs)
Filter Pack
Interval
(Feet bgs)
Well
Diameter
(inches)
Borehole
Diameter
(inches)
39.8779464
-121.4408264
0
309-344
309-344
10
12
Shallow Screen
39.87821558
-121.9570981
148
70-100
60-115
2.5
12
Intermediate Screen
39.87821558
-121.9570981
148
320-340
309-351
2.5
12
Deep Screen
39.87821558
-121.9570981
148
510-540
499-556
2.5
12
Well I.D.
PW-HP-1
MW-HP-1
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Prior to startup of the aquifer test, the pumping well and observation wells were outfitted with pressure
transducers to record water level changes. Pressure transducers used for the aquifer tests were the InSitu Level Troll 500 vented transducers (Figure 3-2). The vented transducers self-correct for barometric
changes eliminating the need for a barometer during the tests. The property owner also insured that
irrigation wells PW-HP-2 through PW-HP-4 (Figure 3-1) were not operated during the aquifer test so no
monitoring of these wells were included during the aquifer test. Well PW-HP-5 shown on Figure 3-1 is a
supply well for a nearby gravel mine. It is believed that this well did operate during the aquifer test
based on the response of the deep observation well within MW-HP-1 as discussed in Section 4.1.
Figure 3-2. Picture of typical pressure transducer used for LTA aquifer tests. Length of cable will vary.
Immediately before pumping began, static water levels were recorded for the pumping well and the
primary observation wells using a hand held electric well sounder. Table 3-2 summarizes the results of
these measurements. The pressure transducers were then set to record water levels every one second
for a minimum of 1-hour after startup of the test. The pressure transducers were then reprogramed to
record water levels every minute if there was a water level change greater than 0.1 feet, otherwise water
levels were recorded every 10-minutes.
Table 3-2. Summary of Static Water Level Measurements
Well I.D.
PW-HP-1
Depth to Water
Pressure Transducer Reading
(feet of water above)
(feet below measure point)
Measuring Point Elevation
(feet above mean sea level)
69.325
39.63
217.91
Shallow Screen
40.564
34.64
219.59
Intermediate Screen
58.890
41.72
219.59
Deep Screen
23.764
44.15
219.59
MW-HP-1
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The aquifer test for the Hackett property started on June 20, 2011 at 8:28 am. Since the aquifer test
was conducted during active irrigation of the orchards on the property, the pumping rates were already
established for the pumping well. During the test, flow rates were measured periodically using a Flexim
Fluxus ADM 6725 ultrasonic flow meter (Figure 3-3). This instrument provides a non-invasive method
(no contact with water) to record stable and reliable flow measurements. Table 3-3 summarizes the flow
rates measured during the aquifer test.
Figure 3-3. Flexim Fluxus ADM 6725 Ultrasonic Flow Meter Used To
Measure Flow Rates In Pumping Well During Aquifer Tests
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Table 3-3. Pumping Rates Recorded During Hackett Property
Aquifer Test
Time From Start
(Minutes)
Pumping Rate
(gpm)
0
834
72
813
182
790
538
780
1396
750
1397
880
1399
970
1406
840
1718
808
2797
900
2861
960
3303
925
4224
953
4230
1202
4237
1000
4642
953
5664
785
5982
730
6211
0
During the test, water levels were also periodically measured manually using an electronic well sounder.
Table 3-4 summarizes these measurements.
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Table 3-4. Hand Water Level Measurements Collected During Hackett Property Aquifer Test
Well I.D.
PW-HP-1
Date
Time
(24 hour)
Depth to Water
(feet below measuring point)1
6/20/11
1026
1210
77.05
78.0
6/24/11
1649
44.45
6/20/11
1023
1206
1702
35.97
36.12
36.21
6/21/11
0818
36.54
6/22/11
0815
36.91
6/23/11
0800
37.19
6/24/11
1643
36.12
6/20/11
1022
1205
1701
63.52
64.81
65.17
6/21/11
0817
65.84
6/22/11
0814
69.55
6/23/11
0758
71.66
6/24/11
1642
47.30
6/20/11
1020
1203
1700
43.93
43.94
43.92
6/21/11
0815
43.41
6/22/11
0813
42.94
6/23/11
0756
43.03
6/24/11
1641
44.92
MW-HP-1
Shallow Screen
Intermediate Screen
Deep Screen
1. See Table 3-2
The aquifer test stopped on June 24, 2011 at 4:00 pm for a total pumping time of approximately 103.5
hours. Immediately prior to shut-off, the pressure transducers were reprogramed to record water levels
every 5-seconds. After a minimum of 1-hour after shutoff, the pressure transducers were reprogramed
to record water levels during recovery if there was a water level change greater than 0.1 feet, otherwise
water levels were recorded every 10-minutes. Recovery was recorded for over one month and the
pressure transducers were downloaded on August 16, 2011.
3.2 M&T Ranch Aquifer Test
Figure 3-4 shows a close-up of the aquifer test area conducted on the M&T Ranch including the location
of the pumping well, primary observation wells, and other known irrigation supply wells. For this aquifer
test, the primary observation well was installed as part of the overall LTA project and is designated MWMT-1 (State Well Number (SWN) 23N01W03H002M). Observation well MW-MT-1 is a nested well
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Section 3
consisting of three separate screen intervals within the same borehole. A detailed discussion of the
installation of this well including lithologic information obtained during drilling is presented in the Field
Investigation Report (Brown and Caldwell, 2012b). The pumping well (Figure 3-4) used for this aquifer
test is designated PW-MT-1. Irrigation wells PW-MT-2 and PW-MT-3 are wells that operated during the
aquifer test. As discussed in Section 2.2, well PW-MT-4 is the test production well used for a 1996
aquifer test conducted by DWR (1996). Well construction details for the pumping well and primary
observation wells are provided on Table 3-5.
Figure 3-4. M&T Ranch Aquifer Test Location Illustrating Monitoring Well and Pumping Well Locations
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Table 3-5. Well construction details for M&T Ranch Aquifer Test
Well I.D.
Latitude
Longitude
Distance From
Pumping Well
(Feet)
Screen
Interval
(Feet bgs)
Filter Pack
Interval
(Feet bgs)
Well
Diameter
(inches)
Borehole
Diameter
(inches)
120-410
16
28
PW-MT-1
39.672714
-121.921333
0
150-170
190-210
240-260
340-390
PW-MT-2
39.687629
-121.916563
5,649
-
-
16
28
PW-MT-3
39.670455
-121.928532
2,142
-
-
16
28
Shallow Screen
39.672714
-121.920684
202
355-385
280-400
2.5
12
Intermediate Screen
39.672714
-121.920684
202
570-590
550-610
2.5
12
Deep Screen
39.672714
-121.920684
202
780-820
758-830
2.5
12
MW-MT-1
Prior to startup of the aquifer test, the pumping well and observation wells were outfitted with pressure
transducers to record water level changes using the equipment discussed in Section 3-1. To monitor if
irrigation wells were operated during the test, pressure transducers were also placed in wells PW-MT-2
through PW-MT-5 (Figure 3-4).
Immediately before pumping began, static water levels were recorded for the pumping well and the
primary observation wells using a hand held electric well sounder. Table 3-6 summarizes the results of
these measurements. The pressure transducers were then set to record water levels every one second
for a minimum of 1-hour after startup of the test. The pressure transducers were then reprogramed to
record water levels every 5 minutes if there was a water level change greater than 0.15 feet, otherwise
water levels were recorded every 1-hour.
Table 3-6. Summary of Static Water Level Measurements Prior to M&T Ranch Aquifer Test
Well I.D.
PW-MT-1
Depth to Water
Pressure Transducer Reading
(feet of water above)
(feet below measure point)
Measuring Point Elevation
(feet above mean sea level)
100.08
27.18
133.25
Shallow Screen
74.873
25.51
130.78
Intermediate Screen
22.093
26.84
130.78
Deep Screen
20.815
28.98
130.78
MW-MT-1
The aquifer test for the M&T Ranch started on July 11, 2012 at 9:09 am. Since the aquifer test was
conducted during active irrigation for orchards on the property, the pumping rates were already
established for the pumping well. During the test, flow rates were measured periodically on the pumping
test well and other wells operated during the test using the ultrasonic flow meter described in Section
3.1 (Figure 3-3). Table 3-7 summarizes the flow rates measured during the aquifer test.
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Table 3-7. Pumping Rates Recorded During M&T Ranch Aquifer Test
PW-MT-1
PW-MT-3
PW-MT-2
Pumping Rate
(gpm)
Time From Start
(minutes)
Pumping Rate
(gpm)
Time From Start
(minutes)
Pumping Rate
(gpm)
0
1850
0
0
0
0
5
1765
1900
1690
659
1589
14
1748
2896
1626
1468
1594
28
1743
3193
1622
1874
0
36
1750
3244
1602
114
1775
4492
0
685
1700
1495
1615
2025
1772
2905
1620
3335
1770
3358
1768
6336
0
Time From Start
(minutes)
The aquifer test ended on July 15, 2012 at 6:44 pm for a total pumping time of approximately 105
hours. Recovery was recorded for over 14 hours and the pressure transducers were downloaded on
July 16, 2012.
3.3 Esquon Ranch Aquifer Test
Figure 3-5 shows a close-up of the aquifer test area conducted on the Esquon Ranch including the
location of the pumping wells, primary observation wells, and other known irrigation supply wells. For
this aquifer test, the primary observation well was an existing observation well installed by DWR and is
designated MW-ESQ-1 (SWN 21N02E26E03-06M). Observation well MW-ESQ-1 is a nested well
consisting of four separate screen intervals within the same borehole. A second observation well
installed by DWR was also monitored for this test designated MW-ESQ-2 (SWN 20N02E09M) (Figure 35). The geologic well logs for these two wells are presented in Appendix C. Two pumping wells were
used for this aquifer test designated PW-ESQ-39 and PW-ESQ-40 (Figure 3-5). Other Irrigation wells that
operated during the aquifer test and affected drawdown curves included PW-ESQ-12, PW-ESQ-13, PWESQ-16, and PW-ESQ-22. Well construction details for the pumping well and primary observation wells
are provided on Table 3-8.
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Figure 3-5. Esquon Ranch Aquifer Test Location Illustrating Monitoring Well and Pumping Well Locations
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Table 3-8. Well construction details for Esquon Ranch Aquifer Test
Latitude
Longitude
Distance From
Pumping Well
PW-ESQ-39
(Feet)
PW-ESQ-39
39.6392870
-121.7261900
0
110-520
60-535
16
24
PW-ESQ-40
39.6420260
-121.7290860
1,308
115-515
60-535
16
24
PW-ESQ-12
36.6466360
-121.7315220
3,058
-
-
16
24
PW-ESQ-13
39.6377370
-121.7315770
1,632
-
-
16
24
PW-ESQ-16
39.6341960
-121.7259040
1,875
-
-
16
24
PW-ESQ-22
39.6465290
-121.7392860
4,524
-
-
16
24
Shallow Screen
39.6467793
-121.7262455
2,705
105-115
140-150
70-179
2.5
16
Intermediate
Shallow Screen
39.6467793
-121.7262455
2,705
265-290
250-315
2.5
16
Intermediate Deep
Screen
39.6467793
-121.7262455
2,705
400-410
430-440
474-484
388-518
2.5
16
Deep Screen
39.6467793
-121.7262455
2,705
610-620
590-660
2.5
16
39.6154700
-121.7391190
9,414
130-140
170-180
89-202
2
9.5
Well I.D.
Screen
Interval
(Feet bgs)
Filter Pack
Interval
(Feet bgs)
Well
Diameter
(inches)
Borehole
Diameter
(inches)
MW-ESQ-1
MW-ESQ-2
Prior to startup of the aquifer test, the pumping wells and
observation wells were outfitted with pressure transducers to
record water level changes using the equipment discussed in
Section 3-1. To monitor if irrigation wells were operated during the
test, pressure transducers were also placed in wells PW-ESQ-12,
PW-ESQ-13, PW-ESQ-16, and PW-ESQ-22 (Figure 3-5). Other
irrigation wells identified in the vicinity of the tests were outfitted
with ibuttons (Figure 3-6). These instruments are small (less than
1-inch diameter) and are placed on the discharge pipe of the
irrigation well to record temperature changes that can be used to
tell when the wells are turned on and off. To demonstrate that the
ibuttons were effective in recording startup and shutdown of
irrigation wells, an ibutton was also placed on irrigation well PWESQ-13 that was also equipped with a pressure transducer.
Figure 3-7 shows data collected from both of these instruments
and demonstrates that the ibuttons were effective in recording
startup and shutdown of irrigation wells.
Figure 3-6. Ibutton used to Monitor
Startup and Shutdown of Irrigation Wells
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Figure 3-7. Plot of drawdown data recorded by pressure transducer and temperature data recorded by ibutton
over same time period at irrigation well PW-ESQ-13. When irrigation well is turned on, temperature data
becomes more constant reflecting temperature of water within discharge pipe. When irrigation well turns off,
temperature data reflects fluctuations between night time and day time.
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Due to weather conditions, two aquifer tests were conducted at the Esquon Ranch. Immediately before
pumping began for the first test, static water levels were recorded for the pumping wells, primary
observation wells, and selected irrigation wells using a hand held electric well sounder. Table 3-9
summarizes the results of these measurements.
Table 3-9. Static Water Levels Measured Prior to Startup tf
Esquon Ranch Aquifer Test 1
Depth to Water
(feet below measuring point)
Well I.D.
PW-ESQ-39
45.31
PW-ESQ-40
43.12
PW-ESQ-12
56.39
PW-ESQ-13
57.15
PW-ESQ-16
44.97
PW-ESQ-22
47.62
MW-ESQ-1
Shallow Screen
70.26
Intermediate Shallow Screen
63.70
Intermediate Deep Screen
62.43
Deep Screen
61.99
MW-ESQ-2
29.68
Prior to startup of test 1, the pressure transducers for pumping wells PW-ESQ-39 and PW-ESQ-40 were
set to record water levels every one second for a minimum of 1-hour after startup of the test. These
pressure transducers were then reprogramed to record water levels every 1 minute if there was a water
level change greater than 0.15 feet, otherwise water levels were recorded every 10 minutes. The
pressure transducers for the observation wells and other irrigation wells were set to record water levels
every five seconds for a minimum of 1-hour after startup. These pressure transducers were then
reprogramed to record water levels every 1 minute if there was a water level change greater than 0.1
feet, otherwise water levels were recorded every 10 minutes.
Aquifer test 1 for the Esquon Ranch started on May 5, 2011 at 9:45 a.m. by turning on pumping well PWESQ-39. After reviewing the water level within pumping well PW-ESQ-39, the transducers for both this
well and pumping well PW-ESQ-40 scheduled to be started on May 6, 2012 were lowered to ensure
water levels did not go below the level of the transducer. The corrections for these transducers are
provided in Table 3-10. After lowering of the transducer, pumping well PW-ESQ-40 was started on May
6, 2011 at 10:42 a.m.
Table 3-10. Corrections for Lowering of Transducers
Date and Time
Transducer Reading Before Lowering
(feet of water above transducer)
Transducer Reading After Lowering
(feet of water above transducer)
Correction
(feet)
PW-ESQ-39
5/6/11 10:06 a.m.
17.437
39.830
22.393
PW-ESQ-40
5/6/11 10:27 a.m.
43.407
69.906
26.499
Well I.D.
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Since the aquifer test was conducted during active irrigation of the rice fields on the property, the
pumping rates were already established for the pumping wells. During the test, flow rates were
measured periodically on the pumping test wells and other wells operated during the test using the
ultrasonic flow meter described in Section 3.1 (Figure 3-3). Table 3-11 summarizes the flow rates
measured during the aquifer test.
Table 3-11. Pumping Rates Recorded During Esquon Ranch Aquifer Test 1
Time From Start of Test
(minutes)
Pumping Rate
(gpm)
PW-ESQ-39
0
1460
1496
2941
3734
5132
1780
1721
1660
1500
1430
0
PW-ESQ-40
0
1496
1844
2927
4310
5132
0
1500
1480
1340
1320
0
PW-ESQ-13
0
3193
4573
0
1252
0
PW-ESQ-16
0
1630
4356
5204
0
1340
1230
0
Well I.D.
During the test, water levels were also periodically measured manually using an electronic well sounder.
Table 3-12 summarizes these measurements (note; due to cascading, water levels in pumping wells PWESQ-39 and PW-ESQ-40 could not be measured).
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Table 3-12. Hand Water Level Measurements Collected During Esquon Ranch Aquifer Test 1
Well I.D.
Date
Time
(24 hour)
Depth to Water
(feet below measuring point)
5/7/11
0823
70.38
5/8/11
0725
70.47
5/7/11
0825
74.19
5/8/11
0727
75.75
5/7/11
0827
70.68
5/8/11
0728
72.48
5/7/11
0828
63.61
5/8/11
0729
65.43
5/7/11
0946
31.34
5/8/11
0909
31.37
5/7/11
0903
57.97
5/8/11
0845
Cascading – could not measure
5/7/11
1005
78.09
5/8/11
1022
Cascading – could not measure
5/7/11
0909
49.72
5/8/11
0852
Well pumping. Water level below
transducer
MW-ESQ-1
Shallow Screen
Intermediate Shallow Screen
Intermediate Deep Screen
Deep Screen
MW-ESQ-2
PW-ESQ-12
PW-ESQ-16
PW-ESQ-22
On May 8, 2011 at approximately 11:00 p.m., a lighting strike hit a transformer turning off all of the
pumping wells for a total pumping time of about 85.5 hours. After allowing a minimum of 48 hours for
water levels to recover, the test was restarted on May 13, 2011 at 08:15 a.m. For this test, pumping
wells PW-ESQ-39 and PW-ESQ-40 were started simultaneously. After startup of this test, it was noted
that the clock within the pressure transducers placed in observation well MW-ESQ-1 were not
synchronized with the computer clock used to synchronize the other transducers. Table 3-13 provides
the corrections for times recorded on these transducers.
Table 3-13. Time Corrections MW-ESQ-1 Transducers During Esquon Ranch Aquifer Test 2
Date
Transducer Time
Computer Time
Correction
(minutes:seconds)
Shallow
5/13/11
10:32:07
10:20:19
-12:12
Intermediate Shallow
5/13/11
10:37:29
10:37:15
-00:14
Intermediate Deep
5/13/11
10:30:40
10:19:57
-11:43
Deep
5/13/11
10:34:26
10:22:54
-12:32
Screen Zone
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Table 3-14 summarizes the pumping rates recorded during this second aquifer test.
Table 3-14. Pumping Rates Recorded During Esquon Ranch Aquifer Test 2
Time From Start of Test
(minutes)
Pumping Rate
(gpm)
PW-ESQ-39
0
7379
9024
11687
1750
1390
1395
0
PW-ESQ-40
0
7392
9050
11687
1500
1165
1180
0
PW-ESQ-12
0
5966
7244
8951
10364
0
1203
0
1390
0
PW-ESQ-13
0
394
8942
10482
10493
0
1252
1195
1178
0
PW-ESQ-16
0
5897
9013
11687
1230
1270
1260
0
PW-ESQ-22
0
2988
5966
6156
9584
11484
0
1614
1246
0
1246
0
Well I.D.
Table 3-15 summarizes hand water level measurements collected from observation well MW-ESQ-1
during aquifer test 2.
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Table 3-15. Hand Water Level Measurements for MW-ESQ-1 Collected During Esquon Ranch Aquifer Test 2
Well I.D.
Shallow Screen
Intermediate Shallow Screen
Intermediate Deep Screen
Deep Screen
Date
Time
(24 hour)
Depth to Water
(feet below measuring point)
5/17/11
0921
71.54
5/18/11
1248
71.84
5/19/11
0839
72.13
5/17/11
0922
80.76
5/18/11
1249
80.12
5/19/11
0841
80.17
5/17/11
0924
77.64
5/18/11
1251
77.32
5/19/11
0844
77.28
5/17/11
0925
71.15
5/18/11
1252
72.49
5/19/11
0845
73.05
On May 21, 2011 at 11:03 a.m., another lighting strike hit a transformer turning off all of the pumping
wells for a total pumping time of about 195 hours. Recovery was recorded for over one month and the
pressure transducers were downloaded on June 15, 2011.
3.4 Groundwater Sampling
Groundwater samples were collected from each of the pumping wells used for the aquifer tests during
the LTA project after a minimum of 24 hours after startup of the aquifer tests. A summary of this
sampling including wells sampled and date collected is provided in Table 3-16.
Table 3-16. Summary of Groundwater Sample Collection
Date Collected
Days after Start of Aquifer
Test
PW-ESQ-39
5/20/11
7
PW-ESQ-40
5/20/11
7
PW-MT-1
7/12/12
1
PW-MT-2
7/12/12
1
PW-HP-1
6/24/11
4
Well I.D.
For the M&T Ranch aquifer test an additional groundwater sample was collected from another irrigation
well that was operating during the performance of the test (PW-MT-2; Figure 3-4). Groundwater samples
were collected by filling the containers supplied by the analytical laboratory directly from sampling ports
attached to each of the discharge lines associated with the pumping wells. For cation analysis, water
was field filter with a 0.45 micrometer inline filter. Immediately after sampling field parameters were
recorded including pH, specific conductivity, and temperature. The field meter was inoperative during
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the Hackett Property sampling event, as such; these parameters were not recorded for this groundwater
sample.
Samples were submitted under chain of custody documentation to California Laboratory Services of
Rancho Cordova, California for analysis of cations, anions, and general parameters and to Zymax
Forensics of Escondido, California for analysis of oxygen and deuterium isotopes. Copies of the chain-ofcustody forms and the analytical laboratory reports are presented in Appendix D.
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Section 4
Results and Analysis of LTA Aquifer
Tests
Analysis of the LTA aquifer tests discussed in Section 3 followed a stepwise process focused on
assessing both the characteristics and interactions of the aquifers and calculation of aquifer properties.
The first step involved developing a conceptual hydrogeologic model using the lithologic data obtained
during the drilling of monitoring wells for the project. A clear understanding of the hydrogeology
including identification of geologic formation boundaries is critical to an accurate interpretation of
aquifer test data. For the LTA project, the selected drilling method was based on the ability to provide
depth discrete lithologic samples and strict protocols were developed to identify geologic units from drill
cuttings based on the methods of Blair and others (1991) and presented in Technical Memorandum
Number 1 (Brown and Caldwell, 2010). This detailed geologic information also allowed the placement of
screen intervals within specific hydrogeologic zones that provided detailed data on individual
hydrogeologic zones and interactions between aquifers during the aquifer tests. Having accurate
lithologic data from known well completions also assists in the interpretation of driller’s logs produced
during the installation of pumping wells used for the aquifer tests.
After development of the conceptual hydrogeologic model, drawdown curves from the observation and
pumping wells were visually assessed prior to calculating aquifer parameters. To calculate aquifer
parameters, drawdown curves developed from the aquifer test from pumping wells and observation
wells are compared to type curves developed from mathematical solutions of the flow equation. Type
curves developed from these methods are based on specific assumptions about the characteristics of
the aquifer. For example, the classic Theis solution assumes that the aquifer has infinite areal extent
and is homogeneous, isotropic, and of uniform thickness. If the actual aquifer characteristics are
distinctly different from these assumptions, then the drawdown curves observed for wells during the test
will not match the type curves and aquifer parameters cannot be calculated. However, departures from
the type curves can provide important qualitative interpretations of the aquifer characteristics that are
essential for construction of future groundwater models developed for the basin as a management tool,
design of subsequent aquifer tests, and design and construction of future irrigation and groundwater
supply wells.
After determining if the drawdown curves adequately addressed the assumptions for type curve analysis,
aquifer parameters were calculated using the software package AQTESOLV™. This software package
also includes several diagnostic tools to assess flow regimes to select the appropriate type curve
solution for the data including derivative analyses that are useful for detecting deviations in the rate of
displacement change. As discussed in the AQTESOLV™ Version 4.5 User Guide (Duffield, 2007), this
technique was introduced by Bourdet and others (1983, 1989) to the petroleum industry as a valuable
diagnostic tool that can help identify aquifer responses such as aquifer boundaries, leakage, and
delayed gravity response. Spane and Wurster (1993) furthered the use of these analyses for the
groundwater industry.
This section presents an overview of the hydrostratigraphy within the project boundaries followed by
summaries of the development of the site conceptual hydrogeologic model, visual assessment of
drawdown curves, and analysis using the AQTESOLV™ software package at the three aquifer test sites
discussed in Section 3. A detailed presentation of the quantitative curve matching performed using the
AQTESOLV™ software package for each of the tests is presented in Appendix E. The discussion
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presented in Appendix E for each aquifer test provides a summary of the assumptions develop for each
of the analytical solutions used and an assessment of how actual conditions meet these assumptions.
The complete set of drawdown data recorded by the transducers for each test is included within the
project geodatabase. AQTESOLV also provides a diagnostic statistical report for each of the curve
matching solutions. Copies of these reports are provided in Appendix F.
4.1 Hydrostratigraphy
The Tuscan Formation includes a sequence of variably cemented, interbedded clay, sand, and gravel.
This formation consists predominantly of purple volcanic debris flow deposits and interbedded waterlain
fluvial deposits rich in volcanic detritus, but in many areas containing crystalline basement-derived clasts
and rare tuff beds. The reported occurrence of both channel-lain, clast supported, pebble- and cobblegravel facies and interbedded volcanic-rich debris-flow facies in this formation suggests that debris flows
related to volcanic events episodically choked the ancestral stream/river systems of the area (Blair and
others, 1991).
Helley and Hardwood (1985) divided the Tuscan Formation into four hydrostratigraphic units, labeled
from deepest to shallowest, A through D. Units A and B together define the LTA, the subject of this study,
and units C and D define the Upper Tuscan Aquifer. The approximate extent of the LTA within the project
boundaries is shown on Figure 1-1. Helley and Hardwood (1985) also identified several tuffaceous units
that were used to separate the hydrostratigraphic units that included the Tuff of Hogback Road
(separates Unit D from Unit C), Ishi Tuff Member (separates Unit C from Unit B), and the Nomlaki Tuff
Member (base of Unit A).
Overlying the Tuscan Formation are numerous Quaternary deposits (Qd). For the LTA project this unit
was designated as Qd. This broader definition is employed because the numerous Quaternary
formations others have proposed are based on geomorphic or buried-soil information rather than on
criteria by which formal formations are distinguished. More importantly, the criteria used by others
cannot be accurately distinguished in drill cuttings for classification of stratigraphic samples collected
during the drilling of monitoring wells for the project.
Geologic units underlying the Tuscan Formation within the project area are the Miocene Lovejoy Basalt
and Eocene Ione Formation. As discussed in Section 2.3 some recent investigations have interpreted
the presence of a unit referred to as the Upper Princeton Valley Formation. As defined by Redwine
(1972), the Princeton Submarine Valley System is a morphological feature of the ancestral Sacramento
River Basin and contains the geologic formations described above. For example, the Ione Formation is
used by Redwine to separate the lower and upper Princeton Valley fills and the Lovejoy Basalt is
interpreted to represent the rim rock of the upper Princeton Valley Fill.
4.2 Hackett Property Aquifer Test Analysis
This section summarizes the analysis of the aquifer test conducted between June 20, 2011 and June
24, 2011 at the Hackett Property (Figures 1-1 and 3-1).
4.2.1 Conceptual Hydrogeologic Model
Within the northern portion of the project area where the Hackett Property is located, outcrops of the LTA
consist of classic lahar deposits interbedded with tuff units and fluvial sand and gravels. A lahar is a
type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water that
flows down from a volcano, typically along existing natural drainages. The consistency, viscosity,
approximate density and hardness of a lahar are that of concrete, but change with increased transport
distances.
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A generalized geologic cross section developed using the lithologic logs produced from the observation
well (MW-HP-1) and pumping well (PW-HP-1, Figure 3-1) for this test is presented on Figure 4-1. As seen
on this figure, three separate well screens were constructed within the observation well to monitor zones
within both the Upper and Lower Tuscan Aquifers. The pumping well is reported to be screened within
the same sand zone of the intermediate screen for the observation well between 320 and 340 feet
below ground surface (bgs). Based on field observations, the lahar units were expected to have low
permeabilities and the three screen intervals were placed within sand and gravel zones separated by
significant thicknesses of these units. This design allowed assessment of the interaction between the
aquifers and leakage responses through the low permeability lahar units.
Figure 4-1. Generalized Geologic Cross Section, Hackett Property Aquifer Test.
Pumping Well, PW-HP-1. Observation Well, MW-HP-1.
As indicated in Section 3-1, the pumping well used for the test was connected to an irrigation distribution
system and the water extracted was used for normal irrigation (spray irrigation) practices of a walnut
orchard. As part of this operation, during the test, several line changes were made to irrigate different
portions of the orchard that resulted in changes in the pumping rate. The flow rates for the aquifer test
ranged between 800 gallons per minute (gpm) to 1,200 gpm. No other wells operated within the
orchard during the test.
Figure 4-2 shows the drawdown curves developed for the three screen intervals within the observation
well during the aquifer test. These drawdown curves demonstrate that the intermediate and shallow
zones follow common radial flow drawdown patterns while the deep zone does not. The deep zone
drawdown curve indicates that this aquifer is not in hydraulic connection with the upper two zones. The
drawdown observed from the deep zone well reflects pumping from another well in the area believed to
be used for a nearby gravel mine operation (PW-HP-5; Figure 3-1). Both the intermediate and shallow
drawdown curves show a delayed response to the onset of pumping and to changes in the pumping rate
during modifications to irrigation of the orchard. However, the shallow zone response occurs about one
minute after the intermediate zone suggesting leakage through the lahar package separating these
units.
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Figure 4-2. Drawdown Curves Plotted On Log-Log Diagram for Three Screens of
Hackett Property Observation Well MW-HP-1
For Hackett Property, the aquifer test demonstrates that there are at least two primary aquifers
hydraulically disconnected (deep and intermediate zones). The test also shows that the intermediate
aquifer interacts with a shallow aquifer through a leaky aquitard and that there is significant storage
within the aquitard consistent with observations made during drilling of the observation well.
4.2.2 Quantitative Aquifer Test Analysis
As discussed in the introduction to this section, aquifer analysis used the software package AQTESOLV™.
Based on the conceptual model discussed in Section 4.1.1, the analysis was conducted for the
drawdown curves developed by the pumping well PW-HP-1 and observation well MW-HP-1-Intermediate.
Well construction details for these wells are provided in Table 3-1. The pumping rates during the test are
provided on Table 3-3.
Prior to conducting curve matching, the drawdown data was evaluated using the diagnostic flow plots
provided in AQTESOLV™ that include radial flow plots, linear flow plots, bilinear flow plots, spherical flow
plots, and derivative analysis. A detailed summary of this analysis for each well is provided in Appendix
E. Of particular note from these flow plots are the derivative analysis as an invaluable tool for
diagnosing a number of distinct flow regimes. Examples of flow regimes that one may discern with
derivative analysis include infinite-acting radial flow, wellbore storage, linear flow, bilinear flow, inter-
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porosity flow and boundaries. However, the derivative plot interpretations were developed for a single
pumping well and significant changes in pumping rate or startup of other pumping wells highly affects
interpretations made using these plots. For the Hackett Property aquifer test, pumping rate changes
occurred throughout the test and, as such, the interpretations provided by the derivative analysis are
only suggestive and are isolated to the early to mid-time data before significant changes in pumping rate
occurred.
Figure 4-3 (PW-HP-1) and Figure 4-4 (MW-HP-1-Intermediate) presents the derivative plots for the
Hackett Property aquifer test. As discussed above, the overall plots are skewed by changing pumping
rates during the test. Both plots show the derivative curve attaining a plateau starting at about 25
minutes that indicates infinite acting radial flow. Areas where the derivative plot reaches a plateau are
portions of the drawdown curve appropriate for the Cooper-Jacob straight line method to calculate
transmissivity (T) and storativity (S) values of the aquifer.
Lower Tuscan Aquifer Project
2
10
Obs. Wells
PW-HP-1
1
10
0
Displacement (ft)
10
-1
10
-2
10
-3
10
-4
10
-2
10
-1
10
0
10
1
10
2
10
3
10
4
10
Time (min)
Figure 4-3. Derivative (Green) and Drawdown (Black) Curves for Pumping Well PW-HP-1
4-5
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Lower Tuscan Aquifer Project
2
10
Obs. Wells
MW-HP-1-Intermediate
1
10
Displacement (ft)
0
10
-1
10
-2
10
-3
10
-2
10
-1
10
0
10
1
10
2
10
3
10
4
10
Time (min)
Figure 4-4. Derivative (Green) and Drawdown (Red) Curves for Observation Well MW-HP-1-Intermediate
Early data (between 0.01 minute and 10 minutes) for the pumping well (Figure 4-3) is suggestive of
wellbore storage effects. Accounting for the distortion due to changes in pumping rate, the shape of the
derivative curve for the observation well intermediate screen (Figure 4-4) between 1 minute and 400
minutes could be interpreted as follows:
1. A well in an infinite leaky confined aquifer assuming a partially or fully penetrating line-source
pumping well, an incompressible aquitard, and a constant-head source aquifer. Derivative
plateau at intermediate time indicates infinite-acting radial flow before drawdown departs from
the Theis solution for a nonleaky confined aquifer.
2. A well in an infinite leaky confined aquifer assuming a fully penetrating line-source pumping well,
a compressible aquitard, and a constant-head source aquifer. Derivative plateau at intermediate
time indicates infinite-acting radial flow before drawdown departs from the Theis solution for a
nonleaky confined aquifer.
3. A well in a bounded nonleaky confined aquifer assuming a partially penetrating line source
pumping well and a constant-head (recharge) boundary. Derivative plateau at intermediate time
indicates infinite-acting radial flow. Recharge boundary produces constant drawdown at late
time.
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Item 1 above bests fits the conceptual model presented in Section 4.2.1 that is supported by the
response of observation well MW-HP-1 shallow screen well to pumping that suggests leakage through
the overlying aquitard. As such, curve matching solutions used for quantitative analysis of T and S
values were those that assumed a leaky confined aquifer system. Both the pumping well and
observation well are assumed to be fully penetrating.
As discussed above, areas where the derivative plot reaches a plateau are portions of the drawdown
curve appropriate for the Cooper-Jacob straight line method to calculate T and S values of the aquifer. T
and S values calculated using this method represent preliminary estimates that are useful in
constraining the analysis of the drawdown curves using other solutions. Derivative plots for both the
pumping well (Figure 4-3) and observation well (Figure 4-4) show the derivative curve attaining a plateau
starting at about 25 minutes indicating infinite acting radial flow. The Cooper-Jacob straight line solution
for the pumping well and observation well intermediate screen over this portion of the plots are
presented on Figures 4-5 and 4-6 respectively.
Lower Tuscan Aquifer Project
60.
Obs. Wells
PW-HP-1
Aquifer Model
Confined
Solution
Cooper-Jacob
48.
Displacement (ft)
Parameters
T = 5150.7 ft2/day
S = 0.0006914
36.
24.
12.
0. -2
10
-1
10
0
10
1
2
10
10
3
10
4
10
Adjusted Time (min)
Figure 4-5. Cooper-Jacob Straight Solution for Pumping Well PW-HP-1
Straight line plotted over area representing plateau on derivative plot presented on Figure 4-3.
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Lower Tuscan Aquifer Project
40.
Obs. Wells
MW-HP-1-Intermediate
Aquifer Model
Confined
Solution
Cooper-Jacob
32.
Displacement (ft)
Parameters
T = 4066.3 ft2/day
S = 2.916E-5
24.
16.
8.
0. -2
10
-1
10
0
10
1
10
2
10
3
10
4
10
Adjusted Time (min)
Figure 4-6. Cooper-Jacob Straight Solution for Observation Well MW-HP-1 Intermediate Screen
Straight line plotted over area representing plateau on derivative plot presented on Figure 4-4.
As seen on these figures, T values calculated using the Cooper-Jacob straight method are 4,066 ft2/day
(observation well) to 5,151 ft2/day (pumping well) and the S value for the observation well is 0.00003 (S
values calculated from pumping well are inaccurate). Using an aquifer thickness of 35 feet shown on
Figure 4-1, K values calculated from this method are 116 ft/day to 147 ft/day indicating well sorted
sands or sand and gravel units. The geologic well log produced for observation well MW-HP-1 indicates
this aquifer zone consists of sandy gravels to gravelly sands. The sieve analysis results collected from
330 feet bgs reported 12.5 percent gravels, 85.5 percent sand, and 1.9 percent fines. The calculated S
value supports the intepretation that this aquifer is confined.
Moench (1985) derived a solution for unsteady flow to a fully penetrating, finite-diameter well with
wellbore storage and wellbore skin in a homogeneous, isotropic leaky confined aquifer. In AQTESOLVE™,
there are three configurations for simulating a leaky confined aquifer with aquitard storage for this
method as follows:

Case 1 assumes constant-head source aquifers supply leakage across overlying and underlying
aquitards.

Case 2 replaces both constant-head boundaries in Case 1 with no-flow boundaries

Case 3 replaces the underlying constant-head boundary in Case 1 with a no-flow boundary.
Based on the conceptual model described above and response of the observation wells in the overlying
(MW-HP-1 Shallow – delayed drawdown) and underlying (MW-HP-1-Deep, no response) aquifers, Case 3
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best represents conditions of the aquifer test performed on the Hackett property. Figure 4-7 presents
the Moench (1985) Case 3 solution for observation well MW-HP-1 intermediate. As seen on this plot,
this configuration shows a relatively good fit for the early time and late time data and is considered the
best estimate of T and S values for the aquifer zone analyzed by the Hackett Property aquifer test. Table
4-1 summarizes the T, S, and K (assuming aquifer thickness of 35 feet) values calculated using this
method from the pumping and observation well including values calculated from the recovery tests
(Appendix E). Appendix E also summarizes the assumptions of other analytical solutions used for
analysis of the drawdown data.
Lower Tuscan Aquifer Project
2
10
Obs. Wells
MW-HP-1-Intermediate
Aquifer Model
Leaky
Solution
Moench (Case 3)
Parameters
T = 2321.9 ft2/day
S = 3.606E-5
r/B' = 0.1139
ß' = 0.1081
r/B" = 0.
ß" = 0.
Sw = 0.
r(w) = 0.5833 ft
r(c) = 0.3333 ft
1
Displacement (ft)
10
0
10
-1
10
-2
10
-2
10
-1
10
0
1
10
2
10
10
3
10
4
10
Time (min)
Figure 4-7. Moench (1985) Case 3 Solution For Drawdown Curve Produced For Observation Well MW-HP-1
Intermediate Screen Interval During Hackett Property Aquifer Test
Table 4-1. Summary of T, S, and K values from Moench (1985) solution, Hackett Property aquifer test.
Recovery Analysis
Pumping Test Analysis
T
(ft2/day)
S
(unitless)
K
(ft/day)
T
(ft2/day)
S
(unitless)
K
(ft/day)
PW-HP-1
3555
Na
102
1388
na
40
MW-HP-1 Intermediate
2322
0.00004
66
3078
0.00009
88
Well I.D.
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The reported K values listed in Table 4-1 are consistent with the sandy gravel unit reported for the
aquifer unit observed at 340 feet to 360 feet within the MW-HP-1 soil boring. Reported S values for the
observation well are consistent with the interpretation of a confined aquifer.
Neuman and Witherspoon (1969) derived a solution for unsteady flow to a fully penetrating well in a
confined two-aquifer system. The method allows analyzing data from wells screened in the pumped
aquifer, unpumped aquifer or aquitard. Wells in the aquifers are assumed to be fully penetrating; wells in
the aquitard may be partially penetrating. This method was used for the Hackett Property aquifer test to
provide order of magnitude estimates for T values within the shallow aquifer system.
Figure 4-8 presents the curve solution for observation well MW-HP-1-Intermediate/Shallow using the
Neuman and Witherspoon Method. As seen on this figure, the curve solution for the pumped aquifer
observation well (MW-HP-1-Intermediate) shows a very good fit for both early time and late time data
whereas the curve solution for the unpumped aquifer (MW-HP-1-Shallow) shows a relatively good fit for
early time and late time data
10
Lower Tuscan Aquifer Project
2
Obs. Wells
MW-HP-1-Intermediate
MW-HP-1-Shallow
Aquifer Model
Leaky
10
1
Solution
Neuman-Witherspoon
Displacement (ft)
Parameters
10
10
10
T =
S =
1/B =
ß/r =
T2 =
S2 =
0
1181. ft2/day
9.0E-5
0.002749 ft-1
0.000379 ft-1
5.613E+4 ft2/day
8.0E-9
-1
-2
10
-2
10
-1
10
0
10
1
10
2
10
3
10
4
10
5
Time (min)
Figure 4-8. Neuman-Witherspoon Solution for MW-HP-1 Intermediate/Shallow Screen Zones
The method also assumes that the aquitard or confining bed has infinite areal extent, and uniform
vertical hydraulic conductivity, storage coefficient, and thickness. As indicated above, the method also
does not account for wellbore storage. Actual observations indicate that the confining bed is very
heterogeneous and the unpumped observation well is not fully penetrating. As such, T values calculated
for the unpumped aquifer and K values calculated for the aquitard are considered only estimates. The S
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values calculated from this method are extremely low and are not considered accurate. Table 4-2
summarizes the results of this analysis for the unpumped aquifer and aquitard using the data from
observation well MW-HP-1 Intermediate and MW-HP-1 Shallow. Based on the geologic boring log
produced for MW-HP-1 (Brown and Caldwell, 2012), values presented in Table 4-2 assume the thickness
of the unpumped aquifer is 151 feet and the thickness of the aquitard is 106 feet.
Table 4-2. Estimated T, S, And K Values For Unpumped Shallow Aquifer And Overlying Aquitard For Hackett Property Aquifer Test
Aquitard
Unpumped Shallow Aquifer
T
(ft2/day)
S
(unitless)
K
(ft/day)
T
(ft2/day)
S
(unitless)
K
(ft/day)
Pumping Test Analysis
56,130
0.000000008
372
102
-
0.964
Recovery Analysis
48,500
0.00002
321
263
-
2.482
The estimated K values for the unpumped aquifer are consistent with the coarse sand and gravel units
noted on the geologic boring log produced for observation well MW-HP-1. The estimated K values for the
aquitard are consistent with the fine grained silty sandstones noted for this unit on the geologic boring
log produced for observation well MW-HP-1.
Applying the principle of superposition in time, Theis (1935) proposed a straight-line solution for
determining T and S from residual drawdown data collected during the recovery phase of a pumping test.
The solution assumes a line source for the pumped well and therefore neglects wellbore storage.
Without the influence of boundary effects, the value of S/S' determined from the intercept of the straight
line with the log (t/t') axis should be close to unity. A value of S/S' > 1.0 indicates the influence of
recharge during the test. Conversely, a value of S/S' < 1.0 suggests the presence of a barrier or no-flow
boundary. Figure 4-9 shows the Theis recovery plot for observation well MW-HP-1 Intermediate. As seen
on this figure and the Theis Recovery plot for the pumping well presented in Appendix E, the S/S' values
for both the pumping well (S/S' = 4.01) and observation well (S/S' = 26.87) are greater than 1
suggesting recharge is occurring during the test. This interpretation is consistent with observations
made during the pumping test and the conceptual model discussed above.
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Lower Tuscan Aquifer Project
40.
Obs. Wells
MW-HP-1-Intermediate
Aquifer Model
Confined
32.
Solution
Theis (Recovery)
Residual Drawdown (ft)
Parameters
T = 4026. ft2/day
S/S' = 26.87
24.
16.
8.
0.
10
0
10
1
10
2
10
3
10
4
10
5
10
6
Time, t/t'
Figure 4-9. Theis Recovery Plot for Observation Well MW-HP-1 Intermediate
Value of S/S’ greater than one suggests that recharge is occurring during the test.
4.3 M&T Ranch Aquifer Test Analysis
This section summarizes the analysis of the aquifer test conducted between July 11, 2012 and July 15,
2012 at the M&T Ranch (Figures 1-1 and 3-4).
4.3.1 Conceptual Hydrogeologic Model
The aquifer test completed at the M&T Ranch was conducted in aquifers formed within the distal portion
of the LTA composed predominantly of unconsolidated fluvial material. The hard cemented lahar units
noted in the Hackett Property area are not as prevalent in this area. Overlying the LTA are approximately
160 feet of quaternary deposits formed by the ancestral movement of the Sacramento River system. A
generalized geologic cross section developed using the lithologic logs produced from the observation
(MW-MT-1) and pumping well (PW-MT-1) for this test is presented on Figure 4-10.
Three separate well screens were constructed within the observation well to monitor zones within both
the Upper and Lower Tuscan Aquifers. The pumping well, PW-MT-1, is reported to be screened within the
same sand zone of the shallow screen for the observation well between 280 and 400 feet bgs. The
intermediate well screen was placed within the lower permeable fine grain units between the aquifers
screened by the shallow and deep well screens. This design allowed assessment of the interaction
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between the aquifers and a more detailed assessment of leakage responses through the low
permeability units. The deep zone for this aquifer test is the same aquifer zone described in Section 3-2
tested by DWR in 1996.
Figure 4-10. Generalized Geologic Cross Section, M&T Ranch Aquifer Test. Pumping Well, PW-MT-1.
Observation Well, MW-MT-1.
The aquifer test was conducted for approximately 105 hours from July 11, 2012 to July 15, 2012. The
pumping well used for the test was connected to an irrigation distribution system and the water
extracted was used for normal irrigation (drip irrigation) practices of an almond orchard. As with the
Hackett Property aquifer test, several line changes were made to irrigate different portions of the
orchard that resulted in changes in the pumping rate during the test. The flow rates for the aquifer test
ranged between 1,615 gpm to 1,850 gpm. Two other wells operated during the test, PW-MT-3 located
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approximately 0.4 miles west of the pumping well and PW-MT-2 located approximately 1 mile northnortheast of the pumping well (Figure 3-4). PW-MT-3 operated for approximately 43 hours from June 12,
2012 to June 14, 2012 at rates ranging from 1,602 gpm to 1,690 gpm. PW-MT-2 operated for
approximately 27 hours from July 11, 2012 to July 12, 2012 and 28 hours from July 14, 2012 to the
end of the test on July 15, 2012. The pumping rate for PW-MT-2 averaged about 1,590 gpm. The two
other wells monitored during the test, PW-MT-4 and PW-MT-5 (Figure 3-4) did not operate during the test.
Figure 4-11 shows the drawdown curves developed for the three screen intervals within the observation
well during the aquifer test. These drawdown curves demonstrate that all three zones follow common
radial flow drawdown patterns. The shallow well drawdown curve shows a slight delayed response
(within 10 seconds) to the onset of pumping, changes in the pumping rate during modifications to
irrigation of the orchard, and the turning on and off of PW-MT-3.
Figure 4-11. Drawdown Curves Plotted on Log-Log Diagram for Three Observation Well Screens within MW-MT-1
Used for M&T Ranch Aquifer Test
Both the intermediate and deep well drawdown curves also show a delayed response but the first
response is a rise in water level at approximately two minutes after the onset of pumping. This response
cannot be seen on Figure 4-11 that plots drawdown on a logarithmic scale (negative numbers do not plot
on logarithmic scales). To illustrate the rise in water levels, Figure 4-12 presents the drawdown curves
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for the intermediate and deep wells plotted on a semi-log plot with drawdown on a linear scale. The
effect of rising water levels in response to pumping was first recognized by Verruijt (1969) who
concluded that the reverse well fluctuations occurred because pumping instantly compressed the
aquifer to force water up the well. Verruijt (1969) referred to this response as the Noordbergum effect.
Figure 4-12. Drawdown Curves Plotted for Intermediate and Deep Well Screens of
Observation Well MW-MT-1 on Semi-Log Diagram
For this region, the aquifer test demonstrates that there are at least two primary aquifers hydraulically
connected within the Tuscan Formation (shallow and deep zones) and that there is significant storage
within the aquitard separating these zones.
4.3.2 Quantitative Aquifer Test Analysis
Based on the conceptual model discussed in Section 4.3.1, the analysis was conducted for the
drawdown curves developed by the pumping well PW-MT-1 and observation well MW-MT-1-Shallow. Well
construction details for these wells are provided in Table 3-5. The pumping rates during the test are
provided on Table 3-7.
A detailed summary of the diagnostic flow plot analyses conducted for the M&T Ranch aquifer test is
provided in Appendix E. For this aquifer test, pumping rate changes occurred throughout the test and, as
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such, the interpretations provided by the derivative analysis are only suggestive and are isolated to the
early to mid-time data before significant changes in pumping rate occurred.
Figure 4-13 presents the observed drawdown curve (red) and the derivative plot (green) for observation
well MW-MT-1-Shallow. The plot for the pumping well (Appendix E) is skewed because of multiple screen
intervals over several aquifer zones. The plot for MW-MT-1-Shallow shows the derivative curve attaining
a plateau starting at about 7 minutes that indicates infinite acting radial flow. For the pumping well a
plateau for the derivative plot is suggested starting at about 10 minutes. As discussed in Section 4.2.2,
areas where the derivative plot reaches a plateau are portions of the drawdown curve appropriate for the
Cooper-Jacob straight line method to calculate transmissivity and storativity values of the aquifer.
10
2
Obs. Wells
MW-MT-1-Shallow
Displacement (ft)
10
10
10
10
10
1
0
-1
-2
-3
10
-2
10
-1
10
0
10
1
10
2
10
3
10
4
10
5
Time (min)
Figure 4-13. Derivative (Green) and Drawdown (Red) Curves for Observation Well MW-MT-1-Shallow
All data for the pumping well shows distortion from the change in pumping rate when the irrigation line
was completely filled after the start of pumping and effects of being screened over several aquifer zones.
As such no specific interpretations from this plot are provided. Data starting at 1900 minutes for the
observation well is distorted from the change in pumping rate when the irrigation line was completely
filled after the start of pumping and the start of pumping well PW-3. However, the shape of the
derivative curve between 1 minute and 1900 minutes for the observation well could be interpreted as
follows:
1. A well in an infinite leaky confined aquifer assuming a partially or fully penetrating line-source
pumping well, an incompressible aquitard, and a constant-head source aquifer. Derivative plateau
at intermediate time indicates infinite-acting radial flow before drawdown departs from the Theis
solution for a nonleaky confined aquifer.
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2. A well in an infinite leaky confined aquifer assuming a fully penetrating line-source pumping well, a
compressible aquitard, and a constant-head source aquifer.
Item 1 above best fits the conceptual model presented in Section 4.2.1 that is supported by the
response of observation well MW-HP-1 intermediate and deep screened wells to pumping that suggest
leakage through the underlying aquitard and hydraulic connection to the deep aquifer. As such, curve
matching solutions used for quantitative analysis of T and S values were those that assumed a leaky
confined aquifer system. Both the pumping well and observation well are assumed to be fully
penetrating.
As discussed above, areas where the derivative plot reaches a plateau are portions of the drawdown
curve appropriate for the Cooper-Jacob straight line method to calculate transmissivity and storativity
values of the aquifer. T and S values calculated using this method represent preliminary estimates that
are useful in constraining the analysis of the drawdown curves using other solutions. Derivative plots for
both the pumping well (Appendix E) and observation well (Figure 4-12) show the derivative curve
attaining a plateau starting at about 10 minutes and 7 minutes, respectively, indicating infinite acting
radial flow. The Cooper-Jacob straight line solution for the observation well shallow screen over this
portion of the plot is presented on Figure 4-14.
20.
Obs. Wells
MW-MT-1-Shallow
Aquifer Model
Confined
Solution
Cooper-Jacob
16.
Displacement (ft)
Parameters
T = 1.505E+4 ft2/day
S = 0.0005284
12.
8.
4.
0. -2
10
-1
10
0
10
1
10
2
10
3
10
4
10
5
10
Adjusted Time (min)
Figure 4-14. Cooper-Jacob Straight Solution for Observation Well MW-MT-1 Shallow Screen
Straight line plotted over area representing plateau on derivative plot presented on Figure 4-12.
The T values calculated using the Cooper-Jacob straight method are 9,399 ft2/day (pumping well) and
15,050 ft2/day (observation well) and the S value for the observation well is 0.0005. Using an aquifer
thickness of 36 feet, K values calculated from this method are 261 ft/day to 418 ft/day indicating a
sand and gravel unit. The geologic well log produced for observation well MW-MT-1 indicates this aquifer
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zone consists of sandy gravels to a conglomerate (clasts noted in drill cuttings up to 6-inches in
diameter). The sieve analysis for the sample collected from 370 feet bgs reported 68.7 percent gravel,
28.7 percent sand, and 2.6 percent fines. The calculated S value supports the interpretation that this
aquifer is confined.
Based on the conceptual model described in Section 4.3.1 and response of the observation wells in the
underlying aquitard (MW-MT-1-intermediate) and deep aquifer (MW-MT-1-deep), Moench (1985) Case 1
(constant-head source aquifers supply leakage across overlying and underlying aquitards) best
represents conditions of the aquifer test performed at the M&T Ranch. Figure 4-15 presents the
Moench (1985) Case 1 solution for observation well MW-MT-1 shallow. As seen on this plot, this
configuration shows a relatively good fit for the early time and late time data and is considered the best
estimate of T and S values for the aquifer zone analyzed by the M&T Ranch aquifer test. Table 4-3
summarizes the T, S, and K (assuming aquifer thickness of 36 feet) values calculated using this method
from the pumping and observation well including values calculated from the recovery tests (Appendix E).
Also included on this table are the estimated T and S values using the two aquifer Neuman-Witherspoon
(1969) solution for the DWR (1996) aquifer test discussed in Section 2.2.4.
2
10
Obs. Wells
MW-MT-1-Shallow
Aquifer Model
Leaky
Solution
1
10
Moench (Case 1)
Displacement (ft)
Parameters
T =
S =
r/B' =
ß' =
r/B" =
ß" =
Sw =
r(w) =
r(c) =
0
10
1.155E+4 ft2/day
0.0004537
0.07976
0.0638
0.
0.
0.
1.167 ft
0.6667 ft
-1
10
-2
10
-2
10
-1
10
0
10
1
10
2
10
10
3
10
4
10
5
Time (min)
Figure 4-15. Moench (1985) Case 1 Solution for Observation Well MW-MT-1 Shallow, M&T Ranch Aquifer Test
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Table 4-3. Summary of T, S, and K Values from Moench (1985) Solution, M&T Ranch Aquifer Test and from
Neuman-Witherspoon Solution for DWR (1996) Aquifer Test
Recovery Analysis
Pumping Test Analysis
T
(ft2/day)
S
(unitless)
K
(ft/day)
T
(ft2/day)
S
(unitless)
K
(ft/day)
PW-MT-1
4384
0.00005
122
18860
-
524
MW-MT-1 Shallow
11550
0.00045
321
20540
0.0003
571
DWR (1996) test results
21250
0.00001
590
-
-
-
Well I.D.
The reported K values listed in Table 4-3 are consistent with the sandy gravel to conglomerate unit
reported for the aquifer unit observed at 350 feet to 390 feet within the MW-MT-1 soil boring. Reported
S values for the observation well are consistent with the interpretation of a confined aquifer.
Figure 4-16 shows the Neuman-Witherspoon (1969) solution for observation well MW-MT-1 Shallow for
unsteady flow to a fully penetrating well in a confined two-aquifer system. The curve solution for this well
shows a very good fit for both early time and late time data. Values for the unpumped aquifer represent
the overlying aquifer where no observation wells occur. For the pumping well, convergence using the
automatic fit would not occur and a visual best fit was poor. It is believed that this poor fit for this
method is due to the fact that the pumping well has screen intervals within other aquifer zones.
2
10
Obs. Wells
MW-MT-1-Shallow
Aquifer Model
Leaky
Solution
Neuman-Witherspoon
1
10
Displacement (ft)
Parameters
T =
S =
r/B =
ß =
T2 =
S2 =
0
10
10
10
1.228E+4 ft2/day
0.0005997
0.1794
0.02046
2.533E+4 ft2/day
0.0001
-1
-2
10
-2
10
-1
0
10
1
10
2
10
3
10
10
4
10
5
Time (min)
Figure 4-16. Neuman-Witherspoon (1969) Solution for Observation Well MW-MT-1 Shallow, M&T Ranch Aquifer
Test. T2 and S2 Represent The T and S Values for the Unpumped Aquifer.
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Table 4-4 summarizes the results of this analysis for the unpumped aquifer and aquitard using the data
from observation well MW-MT-1 Shallow. Based on the geologic boring log produced for MW-MT-1
(Brown and Caldwell, 2012), values presented in Table 4-2 assume the thickness of the unpumped
aquifer is 95 feet and the thickness of the aquitard is 387 feet.
Table 4-4. Estimated T, S, and K values for Unpumped Shallow Aquifer and Overlying Aquitard for M&T Ranch Aquifer Test
Aquitard
Unpumped Shallow Aquifer
Pumping Test Analysis
T
(ft2/day)
S
(unitless)
K
(ft/day)
T
(ft2/day)
S
(unitless)
K
(ft/day)
25330
0.0001
266
1120
-
2.893
The estimated K value for the unpumped aquifer is consistent with the coarse sand and gravely sand
units noted on the geologic boring log produced for observation well MW-MT-1. The estimated K value
for the aquitard is consistent with the fine grained silty sandstones to fine grained sands noted for this
unit on the geologic boring log produced for observation well MW-HP-1.
As seen on the Theis Recovery plots presented in Appendix E, the S/S' values for both the pumping well
(S/S' = 2.171) and observation well (S/S' = 1.393) are greater than 1 suggesting recharge is occurring
during the test. This interpretation is consistent with observations made during the pumping test and
the conceptual model discussed above. Appendix E also summarizes the assumptions of other
analytical solutions used for analysis of the drawdown data.
4.4 Esquon Ranch Aquifer Test
This section summarizes the analysis of the aquifer tests conducted between May 5, 2011 and May 21,
2011 at the Esquon Ranch (Figures 1-1 and 3-5).
4.4.1 Conceptual Hydrogeologic Model
The aquifer test completed at the Esquon Ranch was conducted in aquifers formed within the distal
portions of the Lower Tuscan Aquifer (LTA) composed predominantly of unconsolidated fluvial material
but with some hard cemented reworked lahar units. The Lower Tuscan Formation was observed at the
surface in this area. A generalized geologic cross section developed using the lithologic logs produced
from the observation (MW-ESQ-1) and pumping wells (PW-ESQ-39 and PW-ESQ-40) for this test is
presented on Figure 4-17. Figure 3-5 shows the location of these wells along with other irrigation wells
that were monitored for this test. Four separate well screens were constructed within the observation
well to monitor zones within the LTA (shallow, intermediate shallow and intermediate deep wells) and the
underlying Ione Formation (deep well). The pumping wells, as illustrated on Figure 4-17, are reported to
be screened across the entire interval monitored by both the intermediate shallow and intermediate
deep wells between 110 and 520 feet bgs. The shallow, intermediate shallow and intermediate deep
wells are placed within permeable sand units separated by low permeable fines and lahar units of the
LTA. The deep well is placed within permeable sands of the Ione Formation that is overlain by low
permeability fines and lahar units of the LTA. This design allowed assessment of the interaction
between the aquifers of both the LTA and Ione Formation and an assessment of leakage responses
through the low permeability units.
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Figure 4-17. Generalized geologic cross section, Esquon Ranch Aquifer Test. Tuscan Formation in this area is
part of the LTA. Pumping Wells, PW-ESQ-39 and PW-ESQ-40. Observation Well, MW-ESQ-1.
Due to weather conditions, two separate aquifer tests were conducted at the Esquon Ranch. The first
test was conducted for approximately 85 hours from May 5, 2011 to May 8, 2011. This pumping test
consisted of turning on the first well, PW-ESQ-39 (Figure 3-5), followed by the second well, PW-ESQ-40,
twenty four hours later on May 6, 2011. A second test was conducted from May 13, 2011 to May 21,
2011 for approximately 195 hours. Since the first test indicated that there was not significanct
difference in response in the observation wells to turning on each of the wells individually this aquifer
test consisted of turning on both pumping wells simultaneously.
The pumping wells used for the test were connected to an irrigation distribution system and the water
extracted was used for normal irrigation (flood irrigation) practices of rice fields. The flow rates for the
aquifer test ranged between 1,390 gpm to 1,780 gpm for PW-ESQ-39 and 1,165 gpm to 1,500 gpm for
PW-ESQ-40. Sixteen other wells operated during the test with pumping rates ranging from 940 gpm to
2,605 gpm. Only four wells, PW-ESQ-12 (1,300 gpm), PW-ESQ-13 (1,200 gpm), PW-ESQ-16 (1,300
gpm), and PW-ESQ-22 (1,250 gpm) showed measurable effects to the drawdown curves produced for
MW-ESQ-1. Figure 3-5 shows the location of these wells and their approximate distances from the
observation well and pumping wells used for the test.
Figure 4-18 shows the drawdown curves developed for the four screen intervals within the observation
well during the aquifer tests along with startup and shutdown times for each of the irrigation wells that
affected the drawdown curves. Unlike the other drawdown curves presented above, this plot is
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presented on a linear scale to highlight the differences in response between wells. The drawdown
curves demonstrate that the two intermediate zones follow common radial flow drawdown patterns.
Both of these well drawdown curves show delayed responses to the onset of pumping between 40
minutes (intermediate shallow) and 90 minutes (intermediate deep). Both wells also show responses to
the other four pumping wells discussed above. The drawdown curve for the deep well showed a delayed
response of approximately 1,000 minutes (16.5 hours) and the shape of the curve suggests that
although hydraulically connected, water from this zone has to follow an indirect path to the zone of
pumping used for the test. This observation is consistent with the geologic cross section illustrated on
Figure 4-15 that shows this well completed within the Ione Formation beneath fine grained units of the
Tuscan Formation and suggests that the sands of the Ione Formation in this area connect with the sands
of the Tuscan Formation at a different location. The shallow zone drawdown curve indicates that this
aquifer is not hydraulically connected with the lower zones. The shallow well did respond to pumping
from PW-ESQ-22 (Figure 3-5).
For this region, the aquifer test demonstrates that the primary LTA aquifer is hydraulically connected to
the aquifer within the upper Ione Formation but water from these two zones follow indirect pathways.
The shallow aquifer zone of the LTA in this area is not hydraulically connected with the lower zone of the
LTA.
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Figure 4-18. Drawdown curves plotted on Semi-log diagram for four observation well screens within MW-ESQ-1 used for Esquon Ranch aquifer test. Figure also shows bars indicating startup and shutdown of irrigation wells, weather events that effected
the duration of the aquifer tests, and a brief evaluation of each of the curves with respect to validity for use in quantitative curve matching analysis.
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4.4.2 Quantitative Aquifer Test Analysis
Based on the conceptual model discussed in Section 4.4.1, the analysis was conducted for the
drawdown curves developed by the pumping wells PW-ESQ-39 and PW-ESQ-40 and observation well MWESQ-1-Intermediate Shallow and MW-ESQ-1-Intermediate Deep. Well construction details for these wells
are provided in Table 3-8. The pumping rates during the test are provided on Table 3-11. Analysis was
performed for both the May 6, 2011 (Test 1) and May 13, 2011 (Test 2) aquifer tests. In addition, an
analysis was also performed over the entire aquifer test period, May 6, 2011 to June 12, 2011 (end of
recovery), for the drawdown curves produced for MW-ESQ-Intermediate Shallow.
A detailed summary of the diagnostic flow plot analyses conducted for the Esquon Ranch aquifer tests is
provided in Appendix E. For this aquifer test, pumping rate changes and startup and shutdown of other
irrigation wells that affected the aquifer tests (Table 3-11) occurred throughout the test and, as such, the
interpretations provided by the derivative analysis are only suggestive and are isolated to the early to
mid-time data before significant changes in pumping rate occurred.
Figure 4-19 and Figure 4-20 present the derivative plots for observation wells MW-ESQ-1-Intermediate
Shallow and MW-ESQ-1- Intermediate Deep, respectively, for the test 2 aquifer test. The plot for MWESQ-1-Intermediate Shallow shows the derivative curve attaining a plateau starting at about 100
minutes that indicates infinite acting radial flow. For observation well MW-ESQ-1-Intermediate Deep a
plateau for the derivative plot is suggested starting at about 500 minutes. Areas where the derivative
plot reaches a plateau are portions of the drawdown curve appropriate for the Cooper-Jacob straight line
method to calculate transmissivity (T) and storativity (S) values of the aquifer.
Rancho Esquon Aquifer Testing
2
10
Obs. Wells
MW-EWQ-1-IS
1
Displacement (ft)
10
0
10
-1
10
10
0
10
1
10
2
3
10
10
4
10
5
Adjusted Time (min)
Figure 4-19. Derivative (Green) And Drawdown (Red) Curves For
Observation Well MW-ESQ-1-Intermediate-Shallow
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10
Rancho Esquon Aquifer Testing
2
Obs. Wells
MWESQ1 ID
1
Displacement (ft)
10
Section 4
10
10
0
-1
1
10
10
2
10
3
10
4
Time (min)
Figure 4-20. Derivative (Green) And Drawdown (Red) Curves For Observation Well MW-ESQ-1-Intermediate-Deep
Data starting at 3000 minutes for both observation wells are distorted from the startup of other pumping
wells. However, the shape of the derivative curve between 1 minute and 1900 minutes for the
observation well could be interpreted as follows:
1. A well in an infinite leaky confined aquifer assuming a partially or fully penetrating line-source
pumping well, an incompressible aquitard, and a constant-head source aquifer. Derivative plateau
at intermediate time indicates infinite-acting radial flow before drawdown departs from the Theis
solution for a nonleaky confined aquifer.
2. A well in an infinite leaky confined aquifer assuming a fully penetrating line-source pumping well, a
compressible aquitard, and a constant-head source aquifer.
3. Although very suggestive, a piezometer in a leaky confined channel aquifer assuming a fully
penetrating, line-source pumping well, a compressible aquitard and source aquifer with drawdown.
Item 1 above is interpreted to provide the best fit to the conceptual model presented in Section 4.4.1
that is supported by the response of observation well MW-ESQ-1 deep screened well to pumping that
suggest connection between LTA and underlying aquifer of the Ione Formation. Support for item 3
above is the channel like feature of the Tuscan Formation shown on Figure 4-17 (difference in depth to
top of Ione Formation between PW-ESQ-40 and MW-ESQ-1). Curve matching solutions used for
quantitative analysis of T and S values were those that assumed a leaky confined aquifer system. Both
pumping wells are assumed to be fully penetrating. The two observation wells are partially penetrating.
As discussed above, areas where the derivative plot reaches a plateau are portions of the drawdown
curve appropriate for the Cooper-Jacob straight line method to calculate transmissivity and storativity
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Section 4
Aquifer Performance Test Report
values of the aquifer. T and S values calculated using this method represent preliminary estimates that
are useful in constraining the analysis of the drawdown curves using other solutions. Derivative plots for
the pumping wells during test 2 (Appendix E) show the derivative curve attaining a plateau starting at
about 1 minute to 20 minutes indicating infinite acting radial flow. The observation wells (Figure 4-19
and 4-20) show the derivative curves attaining a plateau starting at about 100 minutes to 500 minutes
for the test 2 aquifer test. Table 4-5 summarized the T, S, and K values calculated using the CooperJacob straight line method for both test 1 and test 2. The K values are calculated assuming an aquifer
thickness of 300 feet.
Table 4-5. T, S, and K Values Calculated Using Cooper-Jacob Straight Line Method for the
Esquon Ranch Test 1 And Test 2 Aquifer Tests
T
(ft2/day)
S
(unitless)
K
(ft/day)
MW-ESQ-1-Intermediate Shallow
21,610
0.0003
72
MW-ESQ-1-Intermediate Deep
20,180
0.0006
67
PW-ESQ-39
16,650
-
56
PW-ESQ-40
17,750
-
59
Test 1
Test 2
MW-ESQ-1-Intermediate Shallow
11,030
0.00009
37
MW-ESQ-1-Intermediate Deep
9,095
0.0003
30
PW-ESQ-39
18,700
-
62
PW-ESQ-40
10,860
-
36
During test 1, PW-ESQ-39 operated by itself for approximately 25 hours allowing for an estimate of T and
S values using the distance-drawdown method. Wells used for this analysis included PW-ESQ-39, PWESQ-40, PW-ESQ-13, and PW-ESQ-16. Figure 4-21 shows the results of this analysis with reported T and
S values of 11,737 ft2/day and 0.001, respectively. Using an aquifer thickness of 300 feet, the
calculated K value for this method is 39 ft/day. This K value and those calculated using the CooperJacob straight line method are indicative of well sorted sands. Based on the geologic well log produced
by DWR for observation well MW-ESQ-1, well sorted sands occur in the zones screened by the
intermediate shallow and intermediate deep screen intervals. Other zones within the aquifer zone
tested are classified as sandstones.
4-26
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Aquifer Performance Test Report
Section 4
Figure 4-21. Distance drawdown method at time equals 1,496 minutes during the Esquon Ranch test 1 aquifer
test. Drawdowns recorded at this time were: PW-ESQ-13 = 2.1 feet; PW-ESQ-16 = 2.88 feet; PW-ESQ-39 = 36.04
feet; and PW-ESQ-40 = 6.5 feet.
Based on the conceptual model described in Section 4.4.1 and response of the observation wells in the
overlying aquifer (MW-ESQ-1-shallow – no response) and deep aquifer (MW-ESQ-1-deep – delayed
response), Moench (1985) Case 3 best represents conditions of the aquifer test performed at the
Esquon Ranch. Figure 4-22 and 4-23 present the Moench (1985) Case 3 solutions for observation wells
MW-ESQ-1-Intermediate Shallow and MW-ESQ-1-Intermediate Deep, respectively, during test 2. As seen
on these plots, this configuration shows relatively good fits for the early time and late time data and is
considered the best estimate of T and S values for the aquifer zone analyzed by the Esquon Ranch
aquifer test. Due to the distance of the observation wells and shortness of the test, test 2 results are
considered more reliable for estimates of T and S values in these wells then the test 1 results. Table 4-6
summarizes the T, S, and K (assuming aquifer thickness of 300 feet) values calculated using this
method from the pumping and observation wells including values calculated from the recovery tests
(Appendix E). The reported K values are consistent with the well sorted sands and sandstones observed
within the aquifer zone on the geologic well log produced for MW-ESQ-1.
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Section 4
Aquifer Performance Test Report
Rancho Esquon Aquifer Testing
2
10
Obs. Wells
MW-EWQ-1-IS
Aquifer Model
Leaky
Solution
Moench (Case 3)
Parameters
T = 2.365E+4 ft2/day
S = 0.0003053
r/B' = 0.2002
ß' = 1.0E-5
r/B" = 0.
ß" = 0.
Sw = 0.
r(w) = 1. ft
r(c) = 0.6667 ft
1
Displacement (ft)
10
0
10
-1
10
0
10
1
10
2
3
10
10
10
4
10
5
Time (min)
Figure 4-22. Moench (1985) Case 3 solution for observation well MW-ESQ-1
Intermediate Shallow, Esquon Ranch test 2 aquifer test.
4-28
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Aquifer Performance Test Report
Section 4
Rancho Esquon Aquifer Testing
2
10
Obs. Wells
MWESQ1 ID
Aquifer Model
Leaky
Solution
Moench (Case 3)
Parameters
T = 1.771E+4 ft2/day
S = 0.0009565
r/B' = 0.3943
ß' = 0.0001594
r/B" = 0.
ß" = 0.
Sw = 0.
r(w) = 1. ft
r(c) = 0.6667 ft
1
Displacement (ft)
10
0
10
-1
10
1
10
2
10
3
4
10
10
10
5
Time (min)
Figure 4-23. Moench (1985) Case 3 solution for observation well MW-ESQ-1 Intermediate Deep,
Esquon Ranch test 2 aquifer test.
4-29
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Section 4
Aquifer Performance Test Report
Table 4-6. Summary of T, S, and K Values from Moench (1985) Solution for
Esquon Ranch Aquifer Test
T
(ft2/day)
S
(unitless)
K
(ft/day)
MW-ESQ-1-Intermediate Shallow
4013
0.00004
13
MW-ESQ-1-Intermediate Deep
2518
0.000004
8.4
PW-ESQ-39
12060
-
40
PW-ESQ-40
9773
-
33
MW-ESQ-1-Intermediate Shallow
2000
0.00002
6.7
MW-ESQ-1-Intermediate Deep
515
000003
1.7
PW-ESQ-39
8446
-
28
PW-ESQ-40
3006
-
10
MW-ESQ-1-Intermediate Shallow
23650
0.0003
79
MW-ESQ-1-Intermediate Deep
17710
0.00096
59
PW-ESQ-39
7602
-
25
PW-ESQ-40
6152
-
21
MW-ESQ-1-Intermediate Shallow
18770
0.0005
63
MW-ESQ-1-Intermediate Deep
12230
0.001
41
PW-ESQ-39
5826
-
19
PW-ESQ-40
6267
-
21
Test 1
Pumping
Recovery
Test 2
Pumping
Recovery
As seen on the Theis Recovery plots presented in Appendix E summarized on Table 4-7, the S/S' values
for the pumping wells and observation wells during test 1 ranged from 0.0311 (MW-ESQ-1-Intermediate
Deep) to 1.796 (PW-ESQ-39). Values greater than 1 suggest recharge is occurring during the test where
conversely values less than 1 suggest the presence of a barrier or no-flow boundary. These observations
during test 1 could represent the presence of a channel feature as observed on the geologic cross
section presented on Figure 4-17 and could be the reason for the distinct differences in T and S values
calculated during the two different tests. During test 2, all values were greater than 1 suggesting
recharge was occurring during this recovery test in all zones monitored for the test. For test 2, this
interpretation is consistent with observations made during the pumping test and the conceptual model
discussed above. The variability between test 1 and test 2 suggest that heterogenities associated with
channelized deposits potentially have limited extent and are affected by the duration differences.
4-30
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Aquifer Performance Test Report
Section 4
Table 4-7. Summary of S/S’ Values Calculated from Theis Recovery Method for Esquon Ranch Aquifer Test
Well I.D
Test 1
Test 2
MW-ESQ-1-Intermediate Shallow
1.007
4.122
MW-ESQ-Intermediate Deep
0.0311
3.274
PW-ESQ-39
1.796
26.76
PW-ESQ-40
1.669
4.434
An analysis was also conducted on the drawdown curve produced for MW-ESQ-1-Intermediate Shallow
during the entire period of test 1 and test 2. Figure 4-24 presents the Moench (1985) Case 3 solution
for this analysis. As seen on this figure, this configuration shows relatively good fits for the early time and
late time data and the T (19,990 ft2/day) and S (0.0002) values are consistent with the values
calculated using the test 2 results. Appendix E also summarizes the assumptions of other analytical
solutions used for analysis of the drawdown data.
Rancho Esquon Aquifer Testing
2
10
Obs. Wells
MW-ESQ-1IS
Aquifer Model
Leaky
Solution
Moench (Case 3)
Parameters
T = 1.999E+4 ft2/day
S = 0.0002221
r/B' = 0.04422
ß' = 0.09687
r/B" = 0.
ß" = 0.
Sw = 0.
r(w) = 1. ft
r(c) = 0.6667 ft
1
Displacement (ft)
10
0
10
-1
10
1
10
2
10
3
4
10
10
10
5
Time (min)
Figure 4-24. Moench (1985) Case 3 solution for observation well MW-ESQ-1 Intermediate Shallow using
drawdown data from both test 1 and test 2 during the Esquon Ranch aquifer test.
4-31
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Section 5
Groundwater Sampling
As introduced in Section 3.4, groundwater samples were collected from each of the pumping wells used
for the aquifer tests and submitted for analysis of cations, anions, and oxygen/deuterium? isotopes. The
results of this testing is summarized in Table 5-1. A detailed discussion of these results in relationship
to potential recharge areas for the aquifer will be presented within the Final Report.
Table 5-1. Summary of Groundwater Samples – LTA Aquifer Testing
Station
PW-HP-1
PW-MT-1
PW-MT-2
PW-ESQ-39
PW-ESQ-40
Date Collected
6/24/2011
7/12/2012
7/12/2012
5/25/2011
5/25/2011
Anions
Units
Total Alkalinity
99
170
180
110
110
mg/L
Bicarbonate as CaCO3
99
170
180
110
110
mg/L
Flouride
NA
0.063
0.061
NA
NA
mg/L
Chloride
2.9
9.4
16
2.1
1.9
mg/L
Nitrate
12
3.2
3.6
1.3
0.55
mg/L
Nitrite as N
<0.10
<0.10
<0.10
<0.10
<0.10
mg/L
Orthophosphate
<0.15
0.1
<0.15
0.25
0.31
mg/L
Sulfate
7.6
6.6
7.5
0.92
0.82
mg/L
Sulfide
<1.0
<1.0
<1.0
<1.0
<1.0
mg/L
Calcium
21
32
38
17
17
mg/L
Boron
NA
0.077
0.087
NA
NA
mg/L
<0.10
<0.10
<0.10
<0.10
<0.10
mg/L
Magnesium
14
22
25
13
14
mg/L
Manganese
<0.02
<0.02
<0.02
0.11
0.16
mg/L
Potassium
16
2.1
1.8
1.8
2.1
mg/L
Sodium
8.6
14
16
8.1
8.6
mg/L
Specific Conductance
230
370
420
NA
NA
umhos/cm
Total Dissolved Solids
190
230
270
NA
NA
mg/L
pH
7.22
NA
NA
NA
NA
Total Hardness as CaCO3
130
170
200
NA
NA
Cations
Iron
General Parameters
mg/L
5-1
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Section 5
Aquifer Performance Test Report
Table 5-1. Summary of Groundwater Samples – LTA Aquifer Testing
Station
PW-HP-1
PW-MT-1
PW-MT-2
PW-ESQ-39
PW-ESQ-40
-9
-9.9
-9.9
-8.6
-8.8
‰
-64.9
-71.4
-71.8
-61.3
-62.2
‰
Temperature
NA1
19.3
19.4
24.9
24.9
C
Specific Conductance
NA1
359
419
208
194
umhos/cm
pH
NA1
7.91
7.84
7.57
7.45
pH Units
Isotopes
δ18O
δD
Field Parameters
1. Field Parameter not collected due to problem with field meter.
2. NA = Not Analyzed
5-2
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Section 6
References
Barlow, P.M., and Moench, A.F., 2011, WTAQ version 2—A computer program for analysis of aquifer tests in confined and
water-table aquifers with alternative representations of drainage from the unsaturated zone: U.S. Geological Survey
Techniques and Methods 3-B9, 41 p.
Bear, J. (1972). Dynamics of Fluids in Porous Media. Dover Publications. ISBN 0-486-65675-6.
Blair, T.C., Baker, F.G., and Turner, J.B., 1991, Cenozoic Fluvial-Facies Architecture and Aquifer Heterogeneity, Oroville,
California, Superfund Site and Vicinity, in A.D. Miall and N. Tyler, eds., The Three-Dimensional Facies Architecture of
Terrigenous Clastic Sediments and Its Implications for Hydrocarbon Discovery and Recovery, SEPM, Concepts in
Sedimentology and Paleontology, Volume 3, 1991.
Bourdet, D., Whittle, T.M., Douglas, A.A. and Y.M. Pirard, 1983, A new set of type curves simplifies well test analysis,
World Oil, May 1983, pp. 95-106.
Bourdet, D., Ayoub, J.A. and Y.M. Pirard, 1989, Use of pressure derivative in well-test interpretation, SPE Formation
Evaluation, June 1989, pp. 293-302.
Busacca, 1982, Geologic history and soil development, northeastern Sacramento Valley, California: Davis, University of
California, Unpubl. Ph.D. Dissertation, 348 p.
Butte County, 2010, Initial Study/Proposed Mitigation Negative Declaration, Lower Tuscan Aquifer Monitoring, Recharge
and Data Management Project, 79 p.
Brown and Caldwell, 2010, Technical Memorandum Number 1: Criteria for Identifying Formational/Unit Boundaries in
Drill Cuttings, August 12, 2010.
Brown and Caldwell, 2011, Technical Memorandum Number 3: Aquifer Performance Test Work Plan, August 5, 2011.
Brown and Caldwell, 2012, Field Investigation Report, Lower Tuscan Aquifer Monitoring, Recharge, and Data
Management Project. October 11, 2012.
Crystal Geyser, 2009, Application for Site Plan Review, October 5, 2009.
Dames & Moore, 1993, Extraction Well Field Report, Initial Phase Off-Property Groundwater Remedial Action; Koppers
Company, Incorporated Superfund Site (Feather River Plant), July 1993.
Duffield, 2007, AQTESOLV™ Version 4.5 User’s Guide, 528 p.
DWR, 1996, M&T Chico Ranch Conjunctive Use Investigation; Phase III, Memorandum Report; December 1996.
DWR, 2009, Glenn-Colusa Irrigation District Test-Production Well Installation and Aquifer Testing, March 2009.
Helly and Hardwood, 1985, Geologic map of the late Cenozoic deposits of the Sacramento Valley and northern Sierran
foothills, California. Department of the Interior - U.S. Geological Survey. Miscellaneous Field Studies Map MF-1790:
1-24 p., 5 sheets, Scale 1:62,500.
Javandel and Tsang, 1986, Capture-Zone Type Curves: A tool for aquifer cleanup. Preprint to the Journal of Groundwater,
12 pp.
Kim and Parizek, 1998, Numerical simulation of the Noordbergum effect resulting from groundwater pumping in a
layered aquifer system: Journal of Hydrology, Volume 206, Issues 1-2: April 1998; p. 149.
McWhorter and Sunada, 1977, Groundwater Hydrology and Hydraulics. Water Resources Publications, Fort Collins, CO,
290 pp.
6-1
P:\38000\138604 - Butte Co. Lower Tuscan Aquifer Inv\Report Deliverables\Aquifer Performance Testing\Final\Final Aquifer Tests Report.docx
Section 5
Aquifer Performance Test Report
Moench, 1985, Transient flow to a large-diameter well in an aquifer with storative semiconfining layers, Water Resources
Research, vol. 21, no. 8, pp. 1121-1131.
Neuman and Witherspoon, 1969, Theory of flow in a confined two aquifer system, Water Resources Research, vol. 5, no.
4, pp. 803-816.
Redwine, 1972, The Tertiary Princeton submarine valley system beneath the Sacramento Valley, California: Univ. of
California, Los Angeles, unpubl. Thesis (PhD): 480 p.
Sheahan, 1971, Type curve solution of step-drawdown test, Groundwater, Volume 9, pp. 25-29.
Spane and Wurster, 1993, DERIV: A computer program for calculating pressure derivatives for use in hydraulic test
analysis, Ground Water, vol. 31, no. 5, pp. 814-822.
Theis, 1935, The relation between the lowering of the piezometric surface and the rate and duration of discharge of a
well using groundwater storage, Am. Geophys. Union Trans., vol. 16, pp. 519-524.
Verruijt, 1969, Elastic storage of aquifers. In: Flow Through Porous Media, edited by R.J.M. De Wiest, Academic Press,
New York. pp. 331-376.
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