ALTERNATIVE PUBLIC SUPPLY WELL LOCATION ANALYSIS
(ZONE II STUDY) IN CAPE COD, MA
by
JUAN CARLOS PEREZ
B.S. Environmental Engineering
Massachusetts Institute of Technology, 1996
Submitted to the Department of Civil and Environmental Engineering
In Partial Fulfillment of the Requirements for the Degree of
MASTER OF ENGINEERING
IN CIVIL AND ENVIRONMENTAL ENGINEERING
at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
June 1997
@ 1997 Juan Carlos Perez
All rights reserved
The authorhereby grants to M.I.T. permission to reproduce and distributepublicly paper
and electronic copies of this thesis document in whole or in part.
I,
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Signature of the Author
lqpartment of Civil ana Environmental Engineering
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Certified by
ay 9,1997
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/F Fnando Miralles-Wilhelm
Professor of Ciivil and Environmental Engineering
Thesis Supervisor
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Accepted by
Professor Joseph Sussman
Chairman, Departn nent Committee on Graduate Studies
JUN 2 4 1997
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ALTERNATIVE PUBLIC SUPPLY WELL LOCATION ANALYSIS
(ZONE II STUDY) IN CAPE COD, MA
by
Juan Carlos Perez
Submitted to the Department of Civil and Environmental Engineering on May 9, 1997, in Partial
Fulfillment of the Requirements for the Degree of Master of Engineering in Civil and
Environmental Engineering
ABSTRACT
Public water supply is a critical issue in Cape Cod, Massachusetts. Extreme dependency on
groundwater, increased levels of land development, and contamination of the aquifer by several
pollutant plumes emanating from the Massachusetts Military Reservation (MMR) make the
process of locating new public water supply wells in the area one of extreme importance. At this
moment, several potential sites are being considered by the Massachusetts Department of
Environmental Protection (DEP) and the Long Range Water Supply Process Action Team. These
sites are located in the northern part of the Cape, near an environmentally sensitive area of the
MMR known as the Live Fire Impact Area (LFIA). For this thesis, two of those sites will be
analyzed in depth.
The main objective of this thesis was the use of a calibrated three-dimensional, finite element
computer model to perform an analysis known in the Commonwealth of Massachusetts as a Zone
II Study. This test is an integral part of the approval process for new public water supply wells.
The purpose of the study is to determine the area of the regional aquifer that contributes to a well
under severe pumping and recharge conditions. The secondary objective of this project was the
inspection of the resulting zones of influence and their paths through the LFIA and the possible
risks of pumping contaminated water from that area of the MMR.
In order to develop this analysis, each well was simulated for a period of 180 days with no
recharge to the system. Furthermore, pumping rates of 600 and 1200 gpm were simulated in each
case. All aquifer characteristics were interpolated from a developed regional flow model based on
the same modeling program.
This study found that the use of this computer model proved to be an excellent tool in the
development of this type of analysis in terms of the effectiveness and accuracy of the results. It
was also found that both wells' zones of influence crossed the LFIA to various extents, and that
the level of intrusion was dependent on factors such as pumping rate, amount of recharge,
location of the well with respect to the aquifer mound, and proximity to the LFIA itself.
Thesis Supervisor: Fernando Miralles-Wilhelm
Title: Professor of Civil and Environmental Engineering
ACKNOWLEDGEMENTS
I would like to express my most sincere gratitude towards Professor Dave H. Marks and
Shawn Morrissey for the work and effort they put in making this program a complete
success. I am deeply in debt to these two gentlemen; if it were not for their belief in me
both as a student and as a person, I would definitely not be here today. Along the same
lines, I would also like to thank Charlie Helliwell and Peter Shanahan for generously
sharing their time and knowledge with us all.
I would like to thank my thesis advisor, Professor Fernando Miralles-Wilhelm, for his
support and advice throughout this semester-long battle. I would certainly not have been
able to complete this thesis without his patience, understanding and most of all, flexibility
towards my slow-coming drafts. Gracias.
Very special thanks to my two unofficial advisors, Bruce Jacobs and Enrique L6pezCalva, gurus of the DynSystem. They were always there when I needed help with the
model or with any of the thousand other things I had trouble with this semester.
I would like to thank the entire M.Eng. crowd, especially Paul Cabral, Dave Lockwood,
Darwin Salipsip, Roberto Le6n, Tina Lin, Mia Lindsey, and the rest of the late night
crew. The members of the Water Resources team must also be acknowledged: Dave
Cook, Jill Manning, Susanna Galloni, Al Tarrel, and Ken Motolenich-Salas.
And last but certainly not least, I would like to thank my mom and dad for all their
sacrifices, endless support, and for being both my greatest role models and best friends.
My brother Jose Eduardo, Cynthia, my best friends Eugene, Soto, and Annabelle, and my
roommates Carlos, Enrique, Jose Oscar, and Victor; thank you all for putting up with me
throughout this chapter of my life. "QVPRL"
..........
.................................................................................................
A B ST RA C T .... ..................
ACKNOWLEDGEMENTS............................................................................................................
LIST OF FIGURES...................................................................
LIST O F TA BLES...........................................................................6
.....
1. INTRO D U CTIO N ...............................................................................
1.1 PROBLEM STATEM ENT ..............................................................
1.2 SCOPE...........................................................................9
1.3 REGULATORY AND SITE BACKGROUND............................
2
3
6
...........
................................
7
................................................
2. ZONE II DELINEATION AND PROTECTION ANALYSIS .............................................................
10
13
13
2 .1 Z O N E II D EFIN ITIO N .............................................................................................................................
15
...................................................
2.2 INFORMATION REQUIREMENTS
15
.............................................
.........................
2.3 PROCEDURE .............. ........
3. MODEL DOCUMENTATION ........................................................................................................
3 .1 PU RP O SE... ...............................................................................
3.2 CONCEPTUAL M ODEL ......................................................
3.3 DATA COLLECTION .....................................
17
............................................................. 17
17
....................
...............................................................................................
3.3.1 Data Sources
3.3.2 Pump Tests..................................................................
..............................
4. M ODEL DEVELOPM ENT ................................................................................
19
19
20
22
22
4.1 DESCRIPTION OF CODE .................................................................
4.2 STUDY A REA ................. .....................................................................
23
.......... 23
......................
4.2.1 Location......................
25
4.2.2 Geology...........................................
27
....................
4.2.3 Hydrology...................................................
29
4.2.4 Hydrogeology ................................................................................
29
......................
4.3 MODEL PARAMETERS......................................................
4.3.1 Bedrock/GroundwaterSurface Elevation..................................................29
30
4.3.2 Boundary Conditions.................................................
4.3.3 MaterialAssignments andProperties.....................................................34
4.3.4 Pumping/RechargeConditions................................................39
.........
..............................
5. M ODEL CALIBRATION ..................................................................................
40
5.1 CALIBRA TION PHILO SOPHY .................................................................................................................. 40
5.2 PU M PIN G R ATES ................................................................................................ 4 1
........ 42
5.3 CALIBRATION OF MATERIAL ASSIGNMENTS AND PROPERTIES ......................................
6. DISCUSSION OF RESULTS ................................................................................
...........................
46
6.1 RESULTING ZONE OF INFLUENCE FOR SIMULATION #1 ........................................................ 49
6.2 RESULTING ZONE OF INFLUENCE FOR SIMULATION #2..................................
6.3
6.4
6.5
6.6
6.7
6.8
RESULTING
RESULTING
RESULTING
RESULTING
RESULTING
RESULTING
..................... 52
ZONE OF INFLUENCE FOR SIMULATION #3........................................................55
..................... 58
ZONE OF INFLUENCE FOR SIMULATION #4..................................
ZONES OF INFLUENCE FOR SIMULATION #5 ................................................ 61
...................... 64
ZONES OF INFLUENCE FOR SIMULATION #6.................................
...................... 67
ZONES OF INFLUENCE FOR SIMULATION #7................................
...................... 70
ZONES OF INFLUENCE FOR SIMULATION #8.................................
..........
71
..........................................
74
7. CONCLUSIONS AND RECOMMENDATIONS ...........................................
8. BIBLIO G RA PH Y ....................................................................................
4
9. A PPEN D IC ES..........................................................................................................................................76
9.1 APPENDIX 1- INFORMATION REGARDING OBSERVATION WELLS ........................................
........ 77
9.2 APPENDIX 2- DESCRIPTION OF GROUNDWATER CODE .................................................. 81
9.3 APPENDIX 3- COMMAND FILES USED IN SIMULATIONS .................................................. 85
LIST OF FIGURES
FIGURE 1 LOCATION OF THE LIVE FIRE IMPACT AREA WITHIN THE MMR SITE ............................................. 8
............... 11
...........
FIGURE 2 PLAN VIEW OF THE STUDY AREA....................................
.................................... 18
FIGURE 3 PLAN VIEW OF WEST CAPE FLOW CELL .....................................
........................ 21
FIGURE 4 TEST WELL LOCATION MAP ........................................
24
FIGURE 5 PLAN VIEW OF SITE 1 ................................................................
FIGURE 6 PLAN VIEW OF SITE 2 ............................................................................. 25
26
FIGURE 7 PLAN VIEW OF SANDWICH AND BUZZARDS BAY MORAINE ................................................
FIGURE 8 WATER TABLE CONTOURS OF THE WEST CAPE FLOW CELL ............................................ 28
....................................................... 30
FIGURE 9 CROSS-SECTION VIEW OF SITE 1
30
FIGURE 10 CROSS-SECTION VIEW OF SITE 2 ...........................................................
32
FIGURE 11 PLAN VIEW OF 3-D NUMERICAL GRID .............................................................
...........
............... 33
FIGURE 12 CLOSER VIEW OF NUMERICAL GRID .......................................
FIGURE 13 BOUNDARY CONDITIONS OF NUMERICAL GRID...........................................................34
FIGURE 14 CROSS-SECTIONAL VIEW OF SITE 1 WITH MATERIALS.............................................. 35
FIGURE 15 CROSS-SECTIONAL VIEW OF SITE 2 WITH MATERIALS.....................................35
FIGURE 16 VIEW OF MATERIALS IN LAYER..................................................
36
FIGURE 17 VIEW OF MATERIALS IN LAYER 2.......................................................36
FIGURE 18 VIEW
FIGURE 19 VIEW
FIGURE 20 VIEW
FIGURE 21 VIEW
FIGURE 22 VIEW
OF MATERIALS
OF MATERIALS
OF MATERIALS
OF MATERIALS
OF MATERIALS
IN LAYER 3........................................................37
IN LAYER 4........................................................37
IN LAYER 5.........................................................38
IN LAYER 6........................................................38
IN LAYER 7.............................
...........................
39
FIGURE 23 INITIAL RESULTS OF CALIBRATION..............................
............... 45
FIGURE 24 FINAL RESULTS OF CALIBRATION..................................................................45
FIGURE 25 CAPTURE ZONE FOR SITE #1 AT 1200GPM UNDER ZERO RECHARGE ......................................
FIGURE 26 CAPTURE ZONE FOR SITE #2 AT 1200 GPM UNDER ZERO RECHARGE ........................................
49
52
FIGURE 27 CAPTURE ZONE FOR SITE # I1AT 600 GPM UNDER ZERO RECHARGE .......................................... 55
FIGURE 28 CAPTURE ZONE FOR SITE #2 AT 600 GPM UNDER ZERO RECHARGE ....................................... 58
FIGURE 29 CAPTURE ZONES
FIGURE 30 CAPTURE ZONES
FIGURE 31 CAPTURE ZONES
FIGURE 32 CAPTURE ZONES
FOR SITES 1 AND 2 AT 1200 GPM UNDER ZERO RECHARGE.............................. 61
FOR SITES 1 AND 2 AT 600 GPM UNDER ZERO RECHARGE................................64
FOR SITES 1 AND 2 AT 1200 GPM UNDER NORMAL RECHARGE..........................67
FOR SITES 1 AND 2 AT 600 GPM UNDER NORMAL RECHARGE...........................70
TABLE 1 OBSERVED FIELD DATA FROM PUMPING TEST ......................................................
TABLE 2 INITIAL AND FINAL VALUES OF MODELED AQUIFER PARAMETERS.................
TABLE 3 CHARACTERISTICS OF INDIVIDUAL SIMULATIONS ......................... ..............
41
........................ 44
................
46
1. INTRODUCTION
1.1 Problem Statement
Public water resources is a critical issue in Cape Cod, Massachusetts. Approximately 96
percent of available water on Cape Cod comes from groundwater (WR report). This area
has experienced a steady rise in the amount of land development throughout the years due
to an increase in tourism and several other factors. Furthermore, the aquifer in this region
is contaminated by various pollutant plumes emanating from the Massachusetts Military
Reservation (MMR) at various locations. For these reasons, the process of locating new
public water supply wells is an extremely important one in terms of both the quantity and
quality of the water which will ultimately be supplied to the area's residents. At this
moment, the Massachusetts Department of Environmental Protection (DEP), together
with the Long Range Water Supply Process Action Team (LRWS-PAT) is evaluating ten
possible sites located in the northwestern part of the Cape, near the towns of Bourne and
Sandwich.
One specific location within the MMR, the Live Fire Impact Area (LFIA), is situated in
the vicinity of the proposed well sites (Figure 1). Of the 22,000 acres occupied by the
MMR, approximately seventy percent, or 14,000 acres, area occupied by the LFIA. This
area has been and is currently used as a place for various forms of target practice. Various
types of small arms, as well as grenades and mortars are fired regularly in this part of the
MMR. Furthermore, tanks and other vehicles hold practice exercises at the site. At this
moment, no specific sources of contamination have been identified and the area is
believed to be free of contamination. However, the effects and final fate of exploded
munitions on the groundwater is not completely understood. Additionally, citizens of the
surrounding communities are concerned about the possibility of contaminants such as
heavy metals, explosives, and explosives by-products leaching into the groundwater of
the aquifer and contributing more pollution problems (Cook, 1997).
Figure 1 Location of the Live Fire Impact Area within the MMR site
The purpose of the model described in this thesis is to analyze two of those ten locations,
Sites 1 and 2, in order to determine the area of the regional aquifer that contributes to
their zones of influence under various conditions. This analysis is known as a Zone II
study in the Commonwealth of Massachusetts. A more detailed description of this
analysis is given in the following sections.
1.2 Scope
This project's main objective will be the use of a calibrated groundwater flow model as a
tool in the development of a Zone II study for both proposed water supply wells. The
secondary objective of this thesis will be to inspect the particular shapes and extents of
the resulting capture zones and their paths through the Live Fire Impact Area and the
possible risks of pumping contaminated water from that area of the MMR site.
This study covers all the technical aspects regarding the delineation of a Wellhead
Protection Area, also known as a Zone II study, for two proposed public water supply
wells in northern Cape Cod. First of all, the process by which new groundwater sources
are found, developed and implemented in the Commonwealth of Massachusetts is
described. Both the particular analysis of interest in this project (Zone II study) and the
larger process to which it belongs to (Source Approval Process) are covered in this
section. After this is done, the model documentation process is covered. In this section,
the conceptual model is presented, the various data sources used for the creation of the
model are mentioned, and the data resulting from the pumping tests performed by Stone
& Webster is shown. Following that, a detailed description of the development of the
flow model is given. First, a summary of the model code used in the project is presented.
Next, the study area is described in detail; emphasis is given to the area in close
proximity to the two proposed well sites in terms of geographic location, geological and
hydrological characteristics and other features of the area. Finally, the model parameters
are covered in this section; bedrock/groundwater surface elevations, boundary conditions,
material assignments and properties, and pumping and recharge conditions are all
discussed here. The next section consists of the calibration process and its various steps,
such as the input of the necessary field data into the model, the simulation of various
pumping rate conditions and the ultimate calibration of the material assignments and
properties. The final two sections of this project deal with the analysis and discussion of
the simulation results and the conclusions and recommendations derived from them.
1.3 Regulatory and Site Background
As mentioned earlier, the Massachusetts DEP, together with the LRWS-PAT, are
considering ten possible sites to construct new public water supply wells. They are
located in the northern part of the Cape, in the towns of Bourne and Sandwich (Figure 4).
The purpose of the model described in this project is to investigate two of those sites,
Sites 1 and 2, in order to determine the area of the regional aquifer that contributes to
these two wells under severe pumping and recharge conditions. These two wells were
chosen out of the ten sites because all pumping tests and preliminary Zone II results have
already been completed for them, which provided me with the necessary field data to
complete the model calibration and furthermore, served as a comparison for my resulting
zones of influence. A plan view of the study area can be seen in Figure 2.
Figure 2 Plan view of the study area
This
Appr<
resou
analy
Regu
Mass,
explo
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The following )utlines the major components of the SAP for all public supply wells
(DEP, 1996):
Step 1: Explore PotentialSources of Groundwater
Step 2: Request Site Exam
Step 3: Conduct Site Exam
Step 4: Assess Viability (for new small systems only)
Step 5:
Submit Pumping Test Proposal
Step 6: Pumping Test ProposalApproved
Step 7." Conduct Pumping Test
Step 8: Shut Down Pumping Test
Step 9: Submit Source FinalReport to DEP Regional Office
Step 10: Source FinalReport Approved
Step 11: Submit Design Planfor Permanent Works to the DEP Regional Office
Step 12: Permanent Works InstallationApproved
Step 13: Notify DEP Regional Office When System is Complete
Step 14: Site Inspection ofPermanent Works
Step 15: Meet Requirements of the Surface Water Treatment Rule
2. ZONE IIDELINEATION AND PROTECTION ANALYSIS
2.1 Zone II Definition
As discussed earlier, the Zone II Study, also known as Wellhead Protection Area
Analysis, forms part of the SAP. Within the Source Approval Process, the Zone II
analysis is performed after the pumping test proposal is approved by the DEP, and its
results are submitted to them in the Source Final Report for further consideration.
The term "Wellhead Protection Area" refers to the surface and subsurface area
surrounding a water well or wellfield supplying a public water system, through which
contaminants are likely to move toward and reach such water well or wellfield (SDWA,
1986). As described by the DEP guidelines: "Zone II means that area of an aquifer which
contributes water to a well under the most severe pumping and recharge conditions that
can be realistically anticipated (180 days of pumping at the approved yield, with no
recharge from precipitation)". It is bounded by the groundwater divides which result
from pumping the well, and by the contact of the aquifer with less permeable materials
such as till or bedrock. In some cases, streams or lakes may act as a recharge boundaries.
In all cases, Zone II shall extend upgradient to its point of intersection with prevailing
hydrogeologic boundaries (DEP, 1996)
Prior to the Zone II study, a Zone I analysis is performed. The purpose of the Zone I
study is to determine the protective radius around a public water system well or wellfield.
The purpose of this protective radius is to insure that land development and other uses
within this area will not have a detrimental effect on the proposed public water supply
well. It also serves the purpose of identifying possible sources of contamination in that
area. For public water systems with approved yields of 100,000 gallons per day (gpd), the
protective radius is 400 feet. For all other public water systems, the protective radius is
determined by the following equation(DEP, 1996):
Zone I radius(ft) = (150 x log of pumping rate in gpd) - 350
As described in the DEP 1996 Guidelines: "The site should not be located within Y mile
ofpotentially serious sources ofpollution such as active or abandonedsanitary landfills,
major fuel storage and/or transmissionsfacilities, road salt stockpile areas, hazardous
substances storage areas,etc."
Zone III is defined as that land area beyond the area of Zone II from which surface water
and groundwater drain into Zone II. The surface water drainage divides as determined by
topography will be used to delineate Zone III. In some locations, where surface and
groundwater are not coincident, Zone III shall consist of both the surface drainage and the
groundwater drainage areas (DEP, 1996).
The major components of the Source Final Report are:
1. All datafrom and analyses of the prolongedpumping test.
2. The delineatedZone II, if applicable,and Zone IIIprotection areas.
3. Groundwater monitoringwell program.
4. Finaldraft or Wellheadprotectionzoning and non-zoning controls.
2.2 Information Requirements
Zone IIs and Zone IIIs shall be delineated for all public water supply wells with planned
yields 100,000 gallons per day (gpd) and greater unless the water supplier can
demonstrate at the time of submittal of the SFP that a groundwater monitoring well
program and an aquifer protection bylaw or ordinance have been implemented that
provide suitable water quality protection for the entire Zone III or watershed area (DEP,
1996).
2.3 Procedure
The Guidelines and Policies for Public Water Systems, from the Massachusetts DEP
outline the procedure for the delineation of a well's zone of contribution or capture zone.
DEP specifies that a 180 day transient simulation be performed with pumping at safe
yield and no recharge. The zone of contribution is then to be delineated using a flow net
approach on the resulting piezometric heads.
The specific steps are:
1. Construct aprepumping water-table contour map.
2. Use a model to predict drawdown under Zone H conditions.
3. Determine Zone II water-table contours by subtracting drawdownsfrom the
prepumping water-table configuration.
4. Construct aflow net using the Zone II water-table contours.
5. Identify the ground-waterdivide using the flow net.
6. Extend the divide upgradient to its point of intersection with prevailing
hydrogeologic boundaries.
3. MODEL DOCUMENTATION
The following description of the Zone II modeling analysis performed for two of the ten
proposed public well sites in the towns of Bourne and Sandwich follows the procedural
guidelines provided by the Division of Water Supply in the Guidelines and Policies for
Public Water Systems (DEP, 1996).
3.1 Purpose
The purpose of the model described in this project is to determine the area of the regional
aquifer that contributes to two of the proposed sites in the towns of Bourne and Sandwich
under severe pumping and recharge conditions.
3.2 Conceptual Model
As shown in Figure 3, Sites 1 and 2 are located on the area of the Cape Cod aquifer
system known as the West Cape flow cell, which is located in the northwestern part of the
Cape. A more detailed description of this flow system will be given later in this project.
The West Cape aquifer is of the unconfined type and its only form of natural recharge is
by infiltration from precipitation. The total thickness of the saturated zone is estimated to
be in excess of 200 feet, with an average depth to water of 70 feet. The highest point of
the water is located beneath the northern portion of the MMR. In general, groundwater
flows radially outward from this mound and ultimately discharges to the ocean. The
aquifer is bounded by the ocean in three sides, with groundwater discharging to Cape Cod
Bay on the North, to Nantucket Sound on the south, and to Buzzards Bay on the west.
The eastern lateral boundary is comprised by the Bass River in Yarmouth.
In geologic terms, the two wells are situated on the Buzzards Bay and Sandwich glacial
moraines, which border the western and northern shores of Cape Cod. These formations
comprise the sole material in the vertical cross-section, with the possibility of some local
variations.
T ruro
flow cell
U_-'______
'F.
WO*·
7000
J
vsol
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Nantucket Sound
Eat cepl
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- --i
-
---
-
i
West Cape
flow cell
Figure 3 Plan view of West Cape Flow Cell
3.3 Data Collection
3.3.1 Data Sources
An initial evaluation of the site by Stone and Webster Engineering Corporation forms the
basis for this study. The results of that work - detailed field logs depicting the test well
layout and vertical geologic characteristics at each of the two sites, a matrix showing the
resulting data from a series of test wells, results of drawdown tests performed on these
test wells, and preliminary Zone I and II results based on analytical models - are
contained in an unpublished draft report which has been given to DEP for further
consideration. Figure 4 shows the locations of all the proposed sites, as presented by
Stone & Webster.
This specific computer model obtains its regional flow and aquifer characteristics from a
regional flow model developed by Susanna Galloni (Galloni, 1997). It incorporates actual
site conditions such as water table contours, stratigraphy, and geologic material properties
into a calibrated model of the entire West Cape flow cell. These and other area
characteristics were interpolated into the computer model from various geologic maps
generated by the United States Geologic Survey (USGS) and several other sources. The
interpolation is then performed based on an initial triangulation between data points along
the study area. The interpolation algorithm employed utilizes a quadratic interpolation
incorporating the computed slope at each data point (CDM, 1991).
Materials regarding DEP regulations and requirements concerning the Source Approval
Process and Zone II studies were obtained from the DEP's Guidelines and Policies for
Public Water Systems and the Massachusetts Drinking Water Regulations. Also, selected
sections of the Federal Safe Drinking Water Act were examined. Furthermore, individual
Zone II studies performed by various private firms were reviewed and studied.
Finally, reports on various issues related to the Cape Cod area were also inspected.
Among these, reports on water resource issues on Cape Cod, simulated pumping and
recharge studies, and various particle tracking studies were studied.
3.3.2 Pump Tests
Pump tests have been performed by Stone & Webster Engineering Corporation at both
Sites 1 and 2. A network of monitoring wells has also been installed as part of the testing
procedure. For each site, a network of seven observation wells was put in place. The
complete information regarding these observation wells is contained in Appendix 1.
Figure 4 Test Well Location Map
21
4. MODEL DEVELOPMENT
4.1 Description of Code
The groundwater flow model code used in this analysis, DynSystem, was developed at
Camp Dresser & McKee (CDM). This modeling package is composed of various
components of which three were used in this study:
* DYNPLOT - a graphical interface code which processes all input and output
* DYNFLOW - processes input files and runs flow simulations
* DYNTRACK - simulates particle transport through the aquifer
DYNFLOW uses a Galerkian finite element formulation to solve the partial differential
equation that describes the transient, three-dimensional flow of a homogeneous
incompressible fluid through a heterogeneous, anisotropic medium. The program uses
linear finite elements, and incorporates induced infiltration from streams, artificial and
natural recharge or discharge, and heterogeneous and anisotropic hydraulic properties.
The program handles both linear (confined) and non-linear (unconfined) aquifer flow
conditions, and has special routines to handle a change in status from a confined to
unconfined situation. The program also has a "rising water" scheme to allow drainage to
local streams if the potentiometric head in a phreatic aquifer rises to the elevation of the
stream bed or land surface (CDM, 1991).
In plan view, a DYNFLOW grid appears to be made up of 2-dimensional triangular
elements. In fact, the DYNFLOW grid allows a three-dimensional representation of the
aquifer statigraphy, with the vertical triangular prism as its fundamental unit. In the
DYNFLOW vernacular, subsurface hydrological units are "layers". The interfaces
between "layers" are referred to as "levels". Nodes are located on "levels" and are the
locations at which the numerical solution is computed. The planar coordinates of a node
do not vary between levels, but the elevation of different nodes in one level can vary. The
DYNFLOW convention is to number layers starting with the lowermost (level 1/ layer 1)
and proceeding upward. A more detailed description of the ground water code is
contained in Appendix 2.
4.2 Study Area
4.2.1 Location
The study area is located on the northeastern part of Cape Cod, Massachusetts (see Figure
2). Cape Cod is located in the southeastern most point of the Commonwealth of
Massachusetts. It is surrounded by Cape Cod Bay on the north, Buzzards Bay on the
west, Nantucket Sound to the south, and the Atlantic Ocean to the east. Cape Cod, a
peninsula, is separated from the rest of Massachusetts by the man-made Cape Cod Canal
(Lizaro, 1996). The MMR is situated in the northern part of western Cape Cod (Figure
1). Previously known as the Otis Air Force Base, the MMR occupies an area of
approximately 22,000 acres (30 square miles) (Lazaro, 1996).
Site 1 is located in the northeastern comer of the study area, in the town of Sandwich. It is
situated approximately one kilometer east of the Upper Shawme Lake, in the area known
as Spruce Swamp. The Mid Cape Highway (Route 3) runs less than 300 meters from the
proposed well location (Figure 5).
Figure 5 Plan view of Site 1
Site 2 is located in the southwestern corner of the study area, in the town of Bourne. It
lies approximately 2 kilometers southeast of Monument Beach and is just off the
MacArthur Boulevard (Route 28) (Figure 6).
Figure 6 Plan view of Site 2
4.2.2 Geology
The geology of western Cape Cod is predominantly composed of glacial sediments
deposited during the Wisconsinan Period (7,000 to 85,000 years ago) (E.C. Jordan,
1989b). As a result of glacial activity during this period, two moraines, the Sandwich
Moraine (SM) and the Buzzards Bay Moraine (BBM), were deposited along the northern
and western edges of western Cape Cod, respectively. Site 1 is located directly on top of
the Sandwich Moraine, while Site 2 sits on top of the Buzzards Bay Moraine (See Figure
7). Between the two moraines lies a broad outwash plain, known as the Mashpee Pitted
Plain (MPP), which is composed of poorly sorted, fine to coarse-grained sands. At the
base of unconsolidated sediments (below the MPP), fine grained, glaciolacustrine
sediment and basal till are present.
I
Figure 7 Plan view of Sandwich and Buzzards Bay Moraine
At the regional scale, both the outwash and moraines have relatively uniform
characteristics even though they contain some local variability. The way the sediments
were deposited, it made the sands stratify and thus made the deposits anisotropic. The
MPP is more permeable and has a more uniform grain size distribution than the moraines.
Nonetheless, both the SM and the BBM have a relatively low fraction of silt and clay,
making it more permeable than similar geologic formations.
The total thickness of the unconsolidated sediments (i.e., moraine, outwash, lacustrine,
and basal till) is estimated to increase from approximately 175 feet near the Cape Cod
Canal in the northwest to approximately 325 feet in its thickest portion in the BBM; it
then decreases to 250 feet near Nantucket Sound in the southern region. The thickness of
the MPP outwash sediments ranges from approximately 225 feet near the moraines to
approximately 100 feet near the shore of Nantucket Sound (E.C. Jordan, 1989b).
4.2.3 Hydrology
Cape Cod's temperate climate produces an average annual precipitation of about 48
inches, widely distributed throughout the year (Masterson and Barlow, 1994). High
permeability sands and low topographic gradient, minimize the potential for runoff and
erosion, and thus recharge values have been reported in the range of 17 to 23 inches/year
(LeBlanc et al., 1986). Consequently, a large fraction of water that precipitates will
migrate to the subsurface. This creates a high probability of contaminant transport from
the surface to the groundwater.
Beneath western Cape Cod lies a single groundwater system (from the Cape Cod Canal to
Barnstable and Hyannis) which the U.S. EPA has designated it as a sole source aquifer.
Sole source designation is granted to an aquifer on the basis of its being needed to supply
50 percent or more of the drinking water for its service area. As mentioned earlier, this
flow system is known as the West Cape Flow Cell, and it is one of six flow cells present
on Cape Cod. Each of the flow cells are hydraulically distinct under present hydrologic
conditions (Guswa and LeBlanc, 1985). The other five flow cells are known as: East
Cape, Eastham, Wellfleet, Truro, and Provincetown flow cells (Figure 3).
The West Cape aquifer is unconfined and its only form of natural recharge is by
infiltration from precipitation. The highest point of the water table (the top of the
groundwater mound) is located beneath the northern portion of the MMR (Figure 8). In
general, groundwater flows radially outward from this mound and ultimately discharges
to the ocean. The aquifer is bounded by the ocean in three sides, with groundwater
discharging to Cape Cod Bay on the North, to Nantucket Sound on the south, and to
Buzzards Bay on the west. The eastern lateral boundary is comprised by the Bass River in
Yarmouth.
Figure 8 Water table contours of the West Cape Flow Cell
Kettle hole ponds, depressions of the land surface below the water table, are common on
the Mashpee Pitted Plains. These ponds influence the groundwater flow on a regional
scale. Streams, wetlands and cranberry bogs serve as drainage to some of these ponds and
as discharge to the groundwater, and thus comprise the rest of the hydrology of the
western cape.
4.2.4 Hydrogeology
The geology and hydrology of western Cape Cod define the hydrogeologic characteristics
of the aquifer. General information on the geology and hydrology of Cape Cod can be
found in the works by Oldale (1982), Oldale and Barlow (1987), Guswa and LeBlanc
(1985), and LeBlanc et al. (1986).Variability of the values may be due to natural
heterogeneities of the soil, but also to differences in measuring techniques and data
analysis (E.C. Jordan, 1989a).
4.3 Model Parameters
Aquifer parameters used in this model, such as hydraulic conductivity, porosity, and
anisotropy ratio, were interpolated from the regional flow model developed by Susanna
Galloni of the Master of Engineering Program, with the use of a feature in the DYNPLOT
program
called
"regional-to-local"
interpolation.
With this option,
all
aquifer
characteristics present in the calibrated regional model are applied to the specific grid
developed for this Zone II study.
4.3.1 Bedrock/Groundwater Surface Elevation
Figures 9 and 10 show the vertical cross-sections depicting the bedrock contours at both
proposed well sites. Bedrock and groundwater elevations in the study area were also
interpolated from the regional flow model.
Site 2
PFEET
I-I-
ground owface
-" '
.............
-
100
8o
00.
.........
...................
40
20
......................··-·····
0
-- 0O
lwver 4
-- eo0
i
*
laverS
!.................................
......
.............................
.i
i
i
-100
- .II
O0
000
·
......................
...............
2500
000
1000
2000
---
..i
8000
FEET
Ire 9 Cross-section view of Site 1
TT il
1FEET
160
. .. lw
grouno sudace
....
..
100
..........
..............
......
.....
......
....
.......
.......
___
8 ..
lee.l3
...
0
I-~C __S TIO
i
14
.........................
...............
...........
.........................................
....
evl3............
...... .......
...........
.............
.............
..............
............
..
...
..............
___
0
-00
__
_
-100
1100
s000
a
600
I00
930-Op
"
.. 00
FJ 3E E""
ire 10 Cross-section view of Site 2
)ns were chosen to coincide with surface water divides,
hce water elevations meet. To the north, the model area is
)n the southern side, both Vineyard and Nantucket Sound
s; Buzzard's Bay serves as the model's boundary on the
western side, and Cape Cod Bay was used on the northeastern side of the model. Finally,
on the eastern side, Bass River is used as the boundary on that area. Along these
boundaries, a condition known as "fixed head" was chosen in DYNPLOT. This is done
for nodes where the head is expected to stay constant but the flux is unknown, such as at
surface water bodies (CDM, 1995).
An automated grid generation routine was used to create the DYNFLOW numerical grid,
within the boundaries described above. A plan view of the finished grid is shown in
Figure 11. As shown earlier in Figures 9 and 10, the grid is divided into 8 levels and 7
layers within them. The top level represents the ground surface elevation at the study
area. The bottom level coincides with the bedrock contours interpolated from various
geologic maps.
Figure 11 Plan view of 3-D numerical grid
The specific shape of the grid was chosen in order to provide more detail in the areas near
the proposed pumping wells. As seen in Figure 12, the level of detail is largest at the
immediate location of the wells and gradually decreases as it goes away from the study
area. Furthermore, the outer shape of the grid follows the outline of the various coasts. As
mentioned in the beginning of this section, this allows for the use of a "fixed head"
boundary condition along those boundaries (Figure 13). On the eastern boundary, the grid
follows the shape of the Bass river.
Figure 12 Closer view of numerical grid
In terms of the vertical detail for this specific flow model, an extra level was added near
the screened sections of both wells. This was done in order to be able to assign flux
values to specific model nodes to simulate both wells' respective pumping rates. On Site
1, the designed pumping rate is divided by two, and each half is assigned to a specific
node on the levels directly above and below the screened section. This does not affect the
results of the simulations since the distance of the approximation is in the order of 5 feet,
and our area of interest is several orders of magnitude larger. Furthermore, the possible
effects of this variation are negligible a short distance away from the well. In the case of
Site 2, the entire flux is assigned to one node in the level located halfway through the
well's screened section.
F = Fixed Head Conditions
R = Rising Head Conditions
Figure 13 Boundary conditions of numerical grid
4.3.3 Material Assignments and Properties
Material assignments and properties were also interpolated from the regional model.
Figures 14 and 15 are vertical cross sections at Sites 1 and 2 which show the materials
present in the vicinity of the pumping wells. These figures show that both sites are
located in areas consisting solely of moraine materials throughout its entire vertical
direction, although on a smaller scale, there may exist some variability in the geologic
materials at one or both of the sites. Figures 16 through 23 show horizontal cross-sections
which depict the materials present at each level in the regional scale.
I
0
FEET
FEET
Figure 15 Cross-sectional view of Site 2 with materials
loraine material is
ttomset vary as it
approaches the ground surface.
Figure 16 View of materials in layer
90
80
70
o
80
°
60
40
30
20
10
0
!
10
20
I
I
I
-10
0
10
20
I
I
I
I
I
30
40
60
60
70
Mdoraine
I
ýEM
80
I
90
100
I
110 120
THOUSANDS OF FEET
Figure 17 View of materials in Layer 2
J
80
E
70
60
40
40
E
30
0
-
20
WY
-
10
-
MATERIALS LAYER 3
=
0
-10
10
20
30
40
60
60
70
Moraine
80 90 100 110 J20
THOUSANDS OF FEET
Figure 18 View of materials in Layer 3
80
70
E
60
-
60
-
40
-
3
30
20
0
E
10F
1
JVI5pv.DG Fl
II
II
-10 0
I
I
I
I
I
I
I
I
10
20
30
40
60
60
70
I
l
I
Moraine
I
I
Figure 19 View of materials in Layer 4
i
I
I
80 90 100 110 120
THOUSANDS OF FEET
Figure 20 View of materials in Layer 5
Figure 21 View of materials in Layer 6
80
70
10
40
.^
-10
0
.
Topeset D
1111
_Bay Lake deposits
STopset P
To]pset M
Moraine
10
20
30
40
50
60
70
00 90
100 110
120
THOUSANDS OF FEET
Figure 22 View of materials in Layer 7
4.3.4 Pumping/Recharge Conditions
In order to determine the zones of influence for Sites 1 & 2, extreme pumping and
recharge conditions had to be simulated. As discussed earlier, DEP Zone II requirements
indicate that the various pumping simulations have to be run at their safe yield rate
constantly for a period of 180 days with no recharge to the model. The specified pumping
rates for the well simulations were determined by DEP to be 600gpm and 1200gpm
(Dayian, Personal Communication).
5. MODEL CALIBRATION
5.1 Calibration Philosophy
The goal of the calibration process is to reproduce an observed system behavior. The
method used in this thesis project was to deduce the distribution of aquifer materials
based on pump tests observations obtained from a series of field tests performed by Stone
& Webster Engineering Corporation for the Massachusetts DEP. The calibration process
involved altering such aquifer characteristics as hydraulic conductivity (Kx & Ky),
Anisotropy ratio (Kx/Kz), Specific storage (S) and Specific yield (Sy) for the various
materials present at both well sites.
The model calibration consisted of running steady-state simulations using the average
recharge rate specified earlier in this project and the specific pumping rates used by Stone
& Webster on the individual pump tests and comparing the drawdowns predicted by the
model to those observed in the field. Table 1 in the following section presents the various
pumping rates used and the various aquifer material values reported for each observation
well.
For this study, both observation wells #6 (Site l's OBS-6 & Site 2's OBS-6) were used
for the calibration of both Sites 1 and 2. These specific wells were chosen because they
are both located a good distance away from the pumping wells, which would probably
provide better results in the drawdown curve analysis. Observation wells located closer to
the actual sites might not completely reflect the effects of drawdown in the test results.
Furthermore, a discharge line was placed some distance from the wells in order to dispose
of the water extracted form the sites during testing, which might have caused some
amount of recharge into the aquifer, thus affecting the results of the tests. As will be seen
later in this section, the location of that discharge line with respect to one of the chosen
observation wells affected the calibration process to some extent.
5.2 Pumping Rates
Pumping tests at Site 1 were performed between 9/6/96 and 9/11/96. They were run for
24 hours a day for a period of 5 days. Tests for Site 2 were performed between 8/14/96
and 8/19/96. As with Site 1, these were also run for 24 hours a day for a total of 5 days. A
network of 7 observation wells was placed in the vicinity of each site. Table 1 shows the
information used and obtained for each observation well.
OBS-5
5
88.3
9.5
0.00025
0.02
17:1
*OBS-6
5
88.3
11.0
0.00050
0.10
14:1
OBS-7
5
88.3
10.5
0.00018
0.02
35:1
OBS-3
5
90.24
12.0
0.00095
0.20
26:1
OBS-4
5
90.24
12.0
0.00053
0.02
49:1
OBS-5
5
90.24
13.7
0.00040
0.10
85:1
*OBS-6
5
90.24
11.6
0.00037
0.10
54:1
Table 1 Observed field data from pumping test
5.3 Calibration of Material Assignments and Properties
Since both Sites 1 and 2 are located directly on the Sandwich and Buzzard's Bay Moraine
respectively, and all the observation wells were placed within these geologic formations,
the calibration process revolved around only those materials which comprised the
moraines.
The model calibration began by simulating the pumping tests performed by Stone and
Webster. All initial test conditions were assigned equal to those used by S&W. As seen in
Table 1, these included test duration, pumping rates (Q), Specific storage (S), Specific
yield (S,), and Anisotropy ratio (Kh/Kz). Before each simulation, the observed drawdowns
were plotted on a log-log scale versus time to obtain the characteristic curve for that test.
After each simulation was completed, the simulated drawdowns were calculated by
obtaining the initial head value for the system and subtracting the resulting head for each
time step. The drawdown was then plotted in the same graph in order to compare both
curves. Then parameters were modified in order to obtain similar curve shapes.
In the case of Site 1, the calibration process involved several steps. As seen in Figure 23,
there was a substantial difference between the simulated and the observed drawdown
curves in the first trial run. In the simulations that followed, the anisotropy ratio was
lowered in order to reduce the amount of drawdown in the system. By reducing the ratio,
the relative impact of the vertical hydraulic conductivity (Kz) is lower than that of the
horizontal hydraulic conductivity (Kx). This means that water will prefer traveling in the
horizontal direction than in the vertical, thus reducing the total drawdown in the system.
Another change introduced in the model was a 10 feet/day raise in both Kx and K, for all
materials that comprised the moraines. This further reduced the drawdown throughout the
entire modeled system. Finally, the Specific storage (S)value in the model was lowered,
which caused the initial drawdown in the aquifer to increase. The value for the Specific
Yield (Sy) was not changed since the final drawdown values were very similar for both
the simulated and observed curves.
In the case of Site 2, calibration was not completed due to various factors found while
inspecting the observed drawdown curves. One of these was the fact that for every
pumping test performed for that site, the observed drawdown followed the classic Theis
curve shape in the test's early stages but after some time proceeded to level out, meaning
that either the tests were not run for enough time or that there was a nearby source of
recharge to the system. One possible explanation for the latter theory is that the
observation wells are located near the discharge line used to dispose of the water
extracted from the wells during testing, which might have been lessening the drawdown
effects at those observation wells.
As described in Introducing Groundwater(Price, 1996): "The complete response of an
unconfined aquifer to pumping can thus be thought of as comprising three stages.
initially, the response is like that of a confined aquifer, with water being releasedfrom
compressible storage; in the second stage, the rate of drawdown decreases as vertical
drainage takes place from saturatedmaterial within the cone of depression; then, as this
drainage catches up with the growth of the cone, the drawdown again follows a Theis
curve, but one correspondingto a higher storage coefficient (the specific yield)". This
quote was extremely helpful during the process of calibration since it described the
processes that affected each part of the drawdown curve, which in turn provided a set of
options and guidelines for the ultimate calibration of the model.
Table 2 shows the initial and final values for each of the parameters involved in the
calibration of Site 1. Only one of the moraine materials is shown since all have identical
values for all parameters except the hydraulic conductivity. Figure 24 shows the final
drawdown curve after calibration for Site 2.
110
110
2:1
.00000225
Table 2 Initial and final values of modeled aquifer parameters
0.10
Initial Drawdown Curves
10
MN
Simulated drawdown
w1_
Obsered drawdown
•----.
0.1
0.1
1
10
100
1000
10000
Elapsed time (min)
Figure 23 Initial results of calibration
Final Calibrated Drawdown Curve
10
Simulated Drawdown
-
E
0.1
0.01
0.1
1
10
100
1000
Elapsed time (min)
Figure 24 Final results of calibration
10000
Observed Drawdown
6. DISCUSSION OF RESULTS
The following sections show the results of the various pumping simulations under
different pumping rates and recharge conditions. Each simulation will be discussed and
its results evaluated. The figures in each section show the water table contours after the
simulation has been run, the resulting capture zones after performing the simulations and
other relevant details. Table 2 shows the various cases that will be simulated and their
specific conditions. Pumping values are presented in [gpm] and recharge values in
[inches/year ].
1200
0
1200
0
600
0
0
0
600
0
1200
1200
0
600
600
0
1200
1200
21.42
600
1200
21.42
Table 3 Characteristics of individual simulations
In order to perform the pumping simulations, the necessary information needs to be
incorporated into the DYNFLOW program. The essential data are: each particular
simulation's pumping rate and the specific location of each screened section, recharge
value for the site, time step and the simulation's total duration time. The command files
used in the simulations can be seen in Appendix 3
Simulation #1
6.1 Resulting zone of influence for Simulation #1
70000
65000
E
60000
-
56000
-
50000
45000
E
40000
E
I
I
II
I
I
I
I
I
0
5000
10000
15000
20000
25000
300O0
35000
Figure 25 Capture Zone for Site #1 at 1200gpm under zero recharge
I
40000
FEET
Observations
Figure 25 depicts the results of the capture zone simulation for Site 1. As indicated in
Table 3, the simulated pumping well at Site 1 was run at 1200 gpm for a period of 180
days with no recharge to the system. The well located at Site 2 was not pumped during
this simulation.
The following observations were made on inspection of the results of this capture zone
simulation:
*
The 180 day drought transients caused the maximum head value of the aquifer to fall
approximately 7 feet, from 65 to 58 feet above sea level.
*
The capture zone of the Site 1 well extends out from the well location in a mostly
southern direction.
*
Site l's capture zone crosses the Live Fire Impact Area on its entire eastern half.
Simulation #2
6.2 Resulting zone of influence for Simulation #2
70000
85000
I-
60000
-
56000
-
50000
-
45000
-
40000
-
35000
E
I
I
I
I
I
I
I
I
0
5000
10000
15000
20000
26000
30000
35000
Figure 26 Capture Zone for Site #2 at 1200 gpm under zero recharge
I
40000
FEET
Observations
Figure 26 shows the results of the capture zone simulation for Site 2. In this case, the
simulated pumping well at Site 2 was run at 1200gpm for a period of 180 days with no
recharge to the system. The well located at Site 1 was not running during this simulation.
The following observations were made on inspection of the results of this capture zone
simulation:
*
The 180 day drought condition again caused the maximum head value of the aquifer
to fall approximately 7 feet, from 65 to 58 feet above sea level.
* The shape of the regional water table contours in this simulation varies very little
from that of simulation #1.
* The capture zone of the Site 2 well extends out from the well location in a
southeasterly direction.
*
Site 2's capture zone crosses the Live Fire Impact Area on its southwestern side.
Simulation #3
6.3 Resulting zone of influence for Simulation #3
Figure 27 Capture Zone for Site #1 at 600 gpm under zero recharge
Observations
Figure 27 depicts the results of the capture zone simulation for Site 1. As indicated in
Table 3, the simulated pumping well at Site 1 was run at 600 gpm for a period of 180
days with no recharge to the system. The well located at Site 2 was not pumped during
this simulation.
The following observations were made on inspection of the results of this capture zone
simulation:
*
The 180 day drought transients caused the maximum head value of the aquifer to fall
approximately 7 feet, from 65 to 58 feet above sea level.
* As with simulation #1, the capture zone of the Site 1 well extends out from the well
location in a southwesterly direction, but with a smaller total area of influence.
*
Site l's capture zone crosses the Live Fire Impact Area on its entire eastern side.
Simulation #4
6.4 Resulting zone of influence for Simulation #4
Figure 28 Capture Zone for Site #2 at 600 gpm under zero recharge
Observations
Figure 28 depicts the results of the capture zone simulation for Site 2. As indicated in
Table 3, the simulated pumping well at Site 2 was run at 600 gpm for a period of 180
days with no recharge to the system. The well located at Site 1 was not pumped during
this simulation.
The following observations were made on inspection of the results of this capture zone
simulation:
* The 180 day drought caused the maximum head value of the aquifer to fall
approximately 7 feet, from 65 to 58 feet above sea level.
* The capture zone of the Site 2 well again extends out from the well location in a
southwesterly direction, but with a smaller total area of influence than in simulation
#2.
*
Site 2's capture zone crosses the Live Fire Impact Area on its eastern side.
Simulation #5
6.5 Resulting zones of influence for Simulation #5
Figure 29 Capture Zones for Sites 1 and 2 at 1200 gpm under zero recharge
Observations
Figure 29 depicts the results of the capture zone simulation for Sites 1 and 2. As indicated
in Table 3, both simulated pumping wells were run at 1200 gpm for a period of 180 days
with no recharge to the system.
The following observations were made on inspection of the results of this capture zone
simulation:
*
The 180 day drought caused the maximum head value of the aquifer to fall
approximately 7 feet, from 65 to 58 feet above sea level.
*
The capture zone of the Site 1 well extends out from the well location in a southerly
direction. The capture zone of the Site 2 well extends southward from the well
location.
*
Site l's capture zone crosses the Live Fire Impact Area on its entire eastern side. Site
2 intrudes on the LFIA's lower left side.
Simulation #6
6.6 Resulting zones of influence for Simulation #6
75000
-
70000
865000
60000
55000
50000
46000
40000
35000 n
o
5000
10000
16000
20000
26000
30000
35000
40000
FEET
recharge
Figure 30 Capture Zones for Sites 1 and 2 at 600 gpm under zero
Observations
Figure 30 depicts the results of the capture zone simulations for Sites 1 and 2. As
indicated in Table 3, both simulated pumping wells were run at 600 gpm for a period of
180 days with no recharge to the system.
The following observations were made on inspection of the results of this capture zone
simulation:
*
The 180 day drought caused the maximum head value of the aquifer to fall
approximately 7 feet, from 65 to 58 feet above sea level.
* Again, the capture zones for this simulation follow the same directions as in
simulation #5, but with a smaller total area of influence caused by the reduced
pumping rates.
Simulation #7
6.7 Resulting zones of influence for Simulation #7
-
76000
70000
66000
60000
-
-
55000
E
50000
E
46000
k
40000
E
I
0
I
I
I
I
I
I
I
5000
10000
16000
20000
26000
0000
35000
II
40000
FEET
Figure 31 Capture Zones for Sites 1 and 2 at 1200 gpm under normal recharge
Observations
Figure 31 depicts the results of the capture zone simulations for Sites 1 and 2. As
indicated in Table 3, both simulated pumping wells were run at 1200 gpm for a period of
180 days with normal recharge to the system.
The following observations were made on inspection of the results of this capture zone
simulation:
*
Final head values for this simulation resembled those of all the previous simulations,
with the maximum head value being lowered by approximately 7 feet.
*
All results obtained in this and the following simulation are identical to those from
simulations #5 and #6. Normal recharge conditions, as opposed to zero recharge
conditions, did not have as much effect on the modeled system as expected.
Simulation #8
6.8 Resulting zones of influence for Simulation #8
75000
-
Site 1
70000
-
65000
E
60000
E
65000
E
50000
-
45000
-
40000
-
35000
-
I
I
I
I
I
I
I
I
I
0
5000
10000
15000
20D00
25000
30000
35000
40000
FEET
Figure 32 Capture Zones for Sites 1 and 2 ,t
,""
. ,---
:::-m! recharge
7. CONCLUSIONS AND RECOMMENDATIONS
Several conclusions can be derived from this study:
The use of this computer model proved to be an excellent tool in the development of this
type of study. It has the ability to incorporate all the necessary requirements for the
delineation of a Zone II study, such as the absence of recharge to the study area for
extended periods of time, and it has the capacity to simulate actual aquifer features such
as varying geologic parameters, natural boundary conditions, and various hydrologic
characteristics such as fixed head and rising water conditions. If developed concisely, it
can provide results comparable to actual ones, but with a shorter time frame and less of a
budgetary constraint than more conventional methods of aquifer analysis.
In terms of the calibration process, it was found that in order to accurately simulate field
conditions, substantial changes had to be made to various hydraulic parameters such as
hydraulic conductivity (horizontal and vertical), specific storage, and anisotropy ratio.
Several factors might have influenced or affected the process, such as the assumption of
no material variability in the vertical direction in the vicinity of both the observation
wells and the pumping wells. Localized material heterogeneity might have played an
important role in the actual field conditions. Also, since the calibration process only
involved moraine materials, actual aquifer response a distance away from the wells was
not completely grasped. Furthermore, in the case of Site 2, the hypothesis of the nearby
discharge line causing some degree of recharge into the system, cannot be completely
supported unless actual site conditions are witnessed. Finally, as seen in the simulation
results, the aquifer had a total drawdown of approximately 7 feet regardless of the
pumping rate or recharge value used. This somewhat extreme effect might have been
generated by the material changes made during the calibration process, by effectively
making it easier for the water in the aquifer to go through both of the moraines, thus
leaving the system.
As seen in the various simulations, all the zones of influence modeled crossed the Live
Fire Impact Area (LFIA) at some point or another. Among the factors which varied the
amount of intrusion into the LFIA were: varying pumping rate, number of pumping units
at a time, and location of site with respect to the LFIA and the top of the aquifer. The
amount of recharge to the aquifer system proved not to be a determining factor in the
shapes and sizes of the resulting zones of influence since for both cases (recharge vs. norecharge) the regional head contours and thus, the wells' capture zones turned out to be
almost identical.
Since the effects and final fate of exploded munitions on the groundwater are not
completely understood (Cook, 1997), I can only speculate as to the increased risk of
having the proposed wells' capture zones draw water from that area. In any case, it is
known that LFIAs can be potential sources of contaminated groundwater (Cook, 1997).
The fact that both sites are located so close to this area of the MMR and to other sources
of contamination, plus the issue of the large amount of recharge the system receives in the
form of rainfall, constantly "flushing" the aquifer, strongly suggests that further research
into the subject is warranted. There is not enough hard evidence to either validate or
discredit that theory, and therefore more effort should be put into it in terms of
regulations or consideration of treatment technologies in conjunction with the installation
of public water supply wells near environmentally sensitive areas such as the Live Fire
Impact Area.
In terms of developing a comparison of the results from the various pumping simulations,
several different conclusions could be reached depending on the primary interest of the
analysis. If the study's main concern is to minimize the amount of intrusion into the
LFIA, then Site 2 is clearly the best option for both pumping rates since the resulting
zones of influence cross through a much smaller portion of the LFIA than Site 1's capture
zones. In the same line of comparison, a pumping rate of 600 gpm will obviously produce
a smaller zone of influence than that created by a rate of 1200 gpm, thus crossing through
a smaller portion of the area. For this comparison, though, other issues such as the
community's water supply requirement have to be taken into consideration.
8. BIBLIOGRAPHY
Aker, M. Personal Communication. Long Range Water Supply Committee, Process
Action Team. Barnstable County, MA.
CDM, 1991. Delineation of Capture Zones for Marshfield Water Supply Wells in Vicinity
of Proposed S.A. Ray Landfill Site, Camp Dresser & McKee, Commonwealth of
Massachusetts, Cambridge, Massachusetts. November 1991.
Cook, D. 1997. The Live Fire Impact Area as a Contaminant Source, Master of
Engineering Thesis, Department of Civil and Environmental Engineering,
Massachusetts Institute of Technology, Cambridge.
Dayian, L. Personal Communication. Department of Environmental Protection, Division
of Water Supply. Lakeville, MA.
DEP, 1991. Guidelines and Policiesfor Public Water Systems. Division of Water Supply,
Department of Environmental Protection, Commonwealth of Massachusetts,
Boston, Massachusetts. August 1991.
Dufresne-Henry, 1995. Determination of Aquifer Protection Zone II, Dufresne-Henry,
Inc., Commonwealth of Massachusetts, Chelmsford, Massachusetts. July 1995.
Galloni, S. 1997. Regional Flow Model of the West Cape Cod Aquifer and Identification
of Pumping Strategiesfor the Water Supply System of the Town of Falmouth,
Master of Engineering Thesis, Department of Civil and Environmental
Engineering, Massachusetts Institute of Technology, Cambridge.
Guswa, J. H., and LeBlanc, D. R. 1985. DigitalModels of GroundwaterFlow in the Cape
Cod Aquifer System, Massachusetts, U.S. Geological Survey, Water Supply Paper.
Horsley & Witten, 1994. Application for Zone II and Zone III Designation for Public
Supply Well #3, Horsley & Witten, Inc., Commonwealth of Massachusetts,
Barnstable, Massachusetts. May 1994.
Lazaro, A. M. 1996. Simulation of Groundwater Contaminant Plume in a Sand and
Gravel Aquifer in Cape Cod, Massachusetts Using a 3D Model, Master of
Engineering Thesis, Department of Civil and Environmental Engineering,
Massachusetts Institute of Technology, Cambridge.
LeBlanc, D. R. Digital models of ground-waterflow in the Cape Cod Aquifer System,
Massachusetts.USGS Water-Supply Paper 2209. 1985.
LeBlanc, D. R., Garabedian, S. P., Hess, K. M., Gelhar, L. W., Quadri, R. D.,
Stollenwerk, K. G., and Wood, W. W. 1991. Large-Scale Natural Gradient
Tracer Test in Sand and Gravel, Cape Cod, Massachusetts. Section 1:
Experimental Design and Observed Tracer Movement, Water Resources
Research, 27(5), 895-910.
L6pez-Calva, E.J., 1996. Analysis of Pumping Schemes for the Extraction of
Contaminated Groundwater at Cape Cod, Massachusetts Using 3D Numerical
Modeling. Master of Engineering Thesis, Department of Civil and Environmental
Engineering, Massachusetts Institute of Technology, Cambridge.
Massachusetts Executive Office of Environmental Affairs, Department of Environmental
Management, Office of Water Resources. Water Resources of Cape Cod, Water
Use, Hydrology, and Potential Changes in Ground Water Levels. Commonwealth
of Massachusetts, Boston, Massachusetts. October 1994.
Masterson, J.P. et al. Use of Particle Tracking to Improve Numerical Model Calibration
and to Analyze Ground-water Flow and ContaminantMigration, MMR, Western
Cap Cod, MA. USGS Open File Report 96-214. 1996.
Masterson, J.P. and P.M. Barlow. Effects of simulated ground-waterflow in Cape Cod,
Martha's Vineyard, and Nantucket Island Basins, Massachusetts.U.S. Geological
Survey (USGS) Open-File Report 94-316. 1994.
Oldale, R. N., 1982. Pleistocene Stratigraphy of Nantucket, Martha's Vineyard, the
Elizabeth Islands, and Cape Cod, Massachusetts, in Wisconsinan Glaciation of
New England, edited by G. J. Larson and B. D. Stone, pp. 1-34, Kendall/Hunt,
Dubuque, Iowa.
Oldale, R. N., and Barlow, R. A. 1987. Geologic Map of Cape Cod and the Islands,
Massachusetts, Misc. Invest. Ser., Map 1-1763, U.S. Geological Survey, Reston,
VA..
Picking, L. Personal Communication. Stone & Webster Engineering Corporation. Boston,
MA.
Price, M. Introducinggroundwater. Chapman & Hall Publishing House. Boundary Row,
London. 1996. 278 pages.
Rose, J. Personal Communication. Department of Environmental Protection, Division of
Water Supply. Lakeville, MA
Ruse, K. Personal Communication. Stone & Webster Engineering Corporation. Boston,
MA.
9. APPENDICES
9.1 Appendix 1- Pumping and observation well schematics
O
ELCNTU~O
TEST WELL CONSTRUCTION LOG
~~~TES
FORM GTG-2.z.1.2ORM GTG-2.22.2
WELL NO. Site 1 Test Well
660 gpm
- 1
59.26 ft. (toc) I
DISCHARGE
REFERENCE EL
I
56.2 ft.
I
GROUND SURFACE EL
14 in. LNA I natural collapse
DREHOLSDLA.
I 14.49 ft. (toc) I
GROUT/BACKFILL
DEPTH TO WATER (STATIC
58/26/96
Mild Steel
I
CASING TYPE
DATE MEASURED
8 in.
40
I
110ft.
LENGTH
NOM. DIA
:;EDULE
I
6 in.
COLUMN
N/A
DEPTH (TOP OF SEAL)
none
I
SEAL
S N!A
I
DEPTH (BOTTCM OF SEA
Aermotor 68HC 850 1
I
105 ft.
i
3
NO. BOWLS
PUMP
I
DEPTH (PUMP INTAKE)
Franklin 50HP
i
PUMP MOTOR
S
110 ft.
I
DEPTH (TOP OF SCREEN:
;tainless steel 40 ft. 18 in. 0.20 1
SCREEN TYPE
LENGTH D!A.
natural collapse
SLOT
I
FILTEA PACK
GEOLOGIC CONDITIONS ENCOUNTERED WHILE
G ARE 0HOWN ON BORING LOG:
l
Iso ft.
I
DEPTH (BOTTOM OF SCREI
CUENT: ANG/MMR
LACTOR: E.C. Thomas DRILLER: Swaitek
153 ft.
PE/METHOD: CME 95 /f-llow Stem Auger
I
i10502
I
DEPTH (EOTToM oF HCLE
ONE & W~Qr9
EWrRONYENTAL S3EfREM3. ,N
CEI :N
S
& W
TI~N~RONMENTAL
FONE
ED &'21a;9
TESTWELL •w
CI~w
TE?!S!WLL
I INSPECTOR ColUrM
IISETRCIr
COMPLETED: 8/22/=8
COMPANY: Store & Webvter
OPN:So~
oie
MONITORING WELL LOG
SITE NO. 1 WELL NO. IAW-6
STO0Jg
a WsUMER !NMIP )NMITAL' :ECt·,Y
i
a OEP"ES. IC.
58.44 ft. (pvc)
REFERENCE EL
S 56.00 ft.
GROUND SURFACE EL
[
conc. 3ft. / natural coliapse
GROUiT/BACKFILL
L12.68 ft. (pvc) I
DEPTH TO WATER (STAT'
S9/6/96
I
i
9in.
S
BOREHOLE DIAMETER
80
;
PVC
I
DATE MEASURED
SCHEDULE
CASING TYPE
I
2.5 in
:
135 ft.
-ENGTH
DIAMETER
97 ft.
DEPTI- (TOP OF SEAL)
bentonite
SEAL
100 ft.
DEPTH (BOTTOM OF SE
1
135 ft.
I
DEPTH (TOP OF SCREFJ
I
1
PVC
10 ft.
80
BCREEN TYPE SCHEDULE
2.5 in.
LENGTH
0.010
SLOT
DIAMETER
natural collapse
FILTER PACK
TE: All depths measured as bgs.
145 ft.
I
E;,TH \~O iTCM OF SCRI
1
145 ft. I
DEPI'H (BOTTOM OF HOL
i
OJECT:
~I
Public Water Supply Eploration Prcr&n
).. 0510502
CULIENT: ANC'MMF
rNTRACTOR: Stor.e & Webster
ILLER: East Coast Thomas
3 TYPE/METHOD: CME 95 / Hollow stem Auger
STARTED. 7jl 8/9
COMPLETED:
7
/22/96
FORM GT
gom
__67
'-"EST WELL CONSTRUCTION LOG
WELL NO. Site 2 Test Well
2.2.2
.2
I-,-t
.
2.37
REFEPENCE
675 gom
DISC.•ARGE
L
81.70 ft.
S
GRCUNC SURFACE F;L
'----
14~~~'in.
INA / natural collapsea
BOEHOLE OAt
S35.46 ft. (toc\
GROUTiBACKF LL
DIEPTH TO WATER (STATICV
Mhid Steel
'9:
;96
CA.SING TYPE
DArE MFASUrED
8 in.
NOM,
N/A
N/A
DEPTH rTOP OF SEAL)
-_-LL
i
1.1
100 ft.L
iA.
LENGT'
cc iLL'UN
,\\•
,\i
r on6
I"
NA
1I
rEPTi (bOT'rOM OF S-E.L)
) I '
Aermctor 68HC 850
3
PUMP
NO. BOWLS
/
95 ft.
i .•
i
DEPTH t;PUMP INTA C
.
. )i.:3
Fra•.
lin 50 HP
PIJMP MOTOR
100 ft.
DEP
H ("OR O'
1
SCREEN)
sinless stel
_
4_0ft. 8in.i0.201
S;•SEi, TYPE
LENGTH
DIA.
SLOT
,-azuraicollapse
1
FILTER PACK
.1
I-
r
L
NOTE: GO' *GIC CCONOIT!ONS FNCOLNTERED WVi-E
DRILLIUG ,'~C SIHOWN CN BORING LOG:
..Q0: 0A105-z
t.
[
40 ft.
i
t
,,
4.. r
-
DR!Lt':
Mwa:t-e
IG T~E,=iHOD: ME es53!Hollow
I
sItrm Auger
i
CF kCL.
SEPTH (BO-: oM0
sT'
C.IJENT. ANCOMDRMLN
COIffI-CTOO. E C. ThOma.t
0otf-b-,
a-------E V --. ii:
: ;T,
S
TARF;E 6a144/6
-I--'-;S3+CL-
:-v V
;
NSP
P
----
lZis
COMPLETID. 6/26f/9
COMPArY. S3tcne & Web'we
I
_
MONITORING WELL LOG
SITE NO. 2 WELL NO, MW-6
STONE & WasMTER ENVRONMENTAL T~E'•CLOi Y &IS1C•s. INC.
104.83 ft. (pvc)I
REFERENCE EL
S102.10 ft.
i
GROUND SURFACE EL
conc. 3ft. / natural collapse
1
GROUT/BACKFILL
[ 56.89
9 in.
ft. (pvc) I
DEPTH TO WATER (STATI'
I
i
BOREI-OLE CIAMETER
PVC
8/14/96
M
DATE MEASURED
80
i
CASING TYPE
2.5 in
148.39 ft.
DIAMETER
I
127 ft.
1
$CHEDUL.
LENGTH
I
DEPTH (TrOP OF SEAL)
bentonite
[
i
SEAL
I
130 ft.
DEPIH (BOTTOM OF SEI
i
148.39 ft.
1 80
PVC
i
CEPTH (TOP OF SCREEN
1
10 ft.
SCREEN TYPE SCHEDULE
LENGTH
2.5 in.
0.010
DIAMETER
SLOT
1
natural collaose
FILTER PACK
TE: All depths measured as bgs.
)JECT: Public Water Supp•y Eoloratior, Program
: CS10502
CLIENT: ANG'MMR
NTRACTOR: Stone &Webster
158.39 ft.
DEPTH (BOTTOM OF SCRE
_1 162 ft.
LLER: East Coast Thomas
DEPTH (BOTTOM OF -IOLI
TYPE/METHOD: CME 75 / Holow Stem Auger
_ _
ISTARTED'
6/14/9
COMPLETED: f/18/6
9.2 Appendix 2- Description of Groundwater Code
Background
The governing equations for three-dimensional ground water flow is [Bear, 19721]:
S,
y aHy) az
a(K a) +-(K
at 8x . x ay Yay
az
where H represents the piezometric head; K., Kf, and K, represent the hydraulic
conductivity in the principal orthogonal coordinate directions; S, is the specific storativity;
and t is time.
Many methods of solving this equation exist. The finite element method, which is used
by DYNFLOW, provides a general solution that offers variable boundary conditions,
aquifer properties and geometry. It has proven to be a robust and flexible method with
a wide range of applications.
Application of the finite element method involves the following steps:
a)
Divide the region under consideration into a finite number of discrete subregions (elements) with simple geometries (e.g., prism, tetrahedra,
prismoids).
b)
Assume the manner in which the piezometric head, H, can vary throughout
each element (i.e., linear, variation, quadratic variation, etc.).
c)
Based on the element geometry, and on the assumption of the head
variation, write linear (local) equations for nodal point flux in terms of the
piezometric head at the nodes defining the element.
d)
Based on the principle of continuity of heads assemble the local equations
for each element into a global system of linear equations.
e)
Solve the global system of equations for the unknown piezometric head or
flux at each node.
Thne global system of finite element equations can be written in the form:
Q,= S4. H;
Where:
(Eq. 2)
Q, is the nodal point flux,
Hi is the nodal point head, and
S4 is tlhe coefficient matrix relating the two
Implementation Aspects of DYNFLOW
The DYNFLOW code implements the simple mathematical relationships described in the
previous section for ground water flow. Written in FORTRAN, it consists of a core
computational program and associated data processing programs. The program has the
ability to simulate ground water flow using one-, two-, and three-dimensional elements,
or any combination of the three types.
In general, a porous, medium will be represented by three-dimensional elements. In
DYNFLOW, the basic working element in three dimensions is a vertical triangular prism
with six nodes as shown in Figure Ia. Using methods presented by Huang, et al. [1979],
the working element is subdivided within the. DYNFLOW code into three computational
elements (tetrahedra) as shown in Figure 1b. The coefficient matrix for each tetrahedron
is then computed, and assembled into the global coefficient matrix. DYNFLOW uses the
same properties within each element of the triangular prism except for the non-linear case
where the phreatic surface spans two working elements in the vertical direction. For this
case, averaging of properties for each tetrahedron is done based on the relative portion
of the tetrahedron in each originally defined working element.
The DYNFLOW code also permits the use of one- and two-dimensional elements
connected to any nodes in the grid, with or without a background matrix of threedimensional elements. DYNFLOW can treat phreatic, confined or mixed conditions, with
the phreatic surface occurring at any node level, or moving between node levels in a
transient case.
In the transient case, either the trapezoidal (Crank-Nickolson) o: implicit time stepping
scheme can be used, and storage terms can be lumped at nodes or distributed in one
of several different ways.
Either the head or flux can be specified at any node. The code calculates the head at
all nodes where the flux is specified and the flux at all nodes where the head is specified.
Distributed flux (recharge) or nodal point flux can be used. In addition, two conditional
,r-r',.,,< n",, specifies that
boundaries can be specified. The first, called "Tne RISn• •,/
the head be fixed at the elevation of the node at any node where the "Dry Condition"
specifies that the head be held at the elevation of the node at any node where the head
tends to fall below the elevation of the node. Boundary condition types and values, and
material properties can be updated at any point in a transient simulation to account for
temporal variations in these parameters.
Nc'eN
A*
(a)
4
A
C:)
-:Y.:oAL;~JUO
()- The
C:)
-
UYEN
zasiz Elme..:h
hreT::a2e::a..
Cz%~z:a:.z-.aZ Elae.zs
83
DYNFLOW also includes pond elements which can be connected to any nodes in the
grid. The code performs mass balance calculations on pond elements given the stagearea-volume relationship of the pond. implicit (calculated by code) and explicit (specified).
fluxes to the pond can be included together with rainfall and evaporation. The pond mass
balance is carried out using an explicit time stepping scheme.
Conditional Boundaries
In may cases, the type of boundary condition such as specified flux, or head, will not be
known in advance of the simulation. In these cases, use of the previously described
conditional boundaries which select the appropriate boundary condition depending on the
system status can be used. The most common of these cases is that of surface
seepage, the so called rising water condition. If the head tends to rise above the surface
elevation then the head is fixed at that elevation. There will be a calculated flux out of
the system at that point.
A second type of conditional boundary condition is the opposite of the rising water
condition. In this case, of the head tends to drop below the elevation of a node, the head
will be fixed at the node. For instance, this is an appropriate condition for a pumping well
where specification of this condition at the pump level will prevent a well from numerically
drying up. Thus, if the applied pumping flow exceeds the yield of the aquifer, the head
is held constant and the resultant: Dumping yield will be calculated.
Comoutation of Flux
All numerical schemes can be shown to preserve mass in terms of nodal point flux. The
equations require that have either the flux or the head be specified for each node in the
system. Normally, the default condition will be a zero applied flux, which would be
representative of internal system nodes. Nodes on geometric boundaries might have
either specified heads or fluxes depending on the particular situation. At any such node,
only the net flux in or out of the system is implicit in Equation 2. This flux is calculated
by back substitution of calculated heads into Equation 2 and equals the specified flux at
all nodes by specified head nodes where it will be the value required to preserve mass
in the system.
9.3 Appendix 3- Command files used in simulations
!COMMAND FILE TO RUN PUMPING SIMULATION #1
!SITE 1 PUMPING AT 1200GPM
!SITE 2 ZERO PUMPING
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rates
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -115508.02 NODE 97 LEVEL 4
FLUX -115508.02 NODE 97 LEVEL 5
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simul.sav
XCFI
!COMMAND FILE TO RUN PUMPING SIMULATION #2
!SITE 2 PUMPING AT 1200GPM
!SITE 1 AT ZERO PUMPING
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rate
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -231016.04 NODE 23 LEVEL 5
!set the time step for the simulation (in days)
DT 15
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simu2.sav
XCFI
!COMMAND FILE TO RUN PUMPING SIMULATION #3
!SITE 1 PUMPING AT 600GPM
!SITE 2 AT ZERO PUMPING
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rate
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -57754.01 NODE 97 LEVEL 4
FLUX -57754.01 NODE 97 LEVEL 5
!set the time step for the simulation (in days)
DT 15
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simu3.sav
XCFI
!COMMAND FILE TO RUN PUMPING SIMULATION #4
!SITE 2 PUMPING AT 600 GPM
!SITE 1 AT ZERO PUMPING
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rate
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -115508.02 NODE 23 LEVEL 5
!set the time step for the simulation (in days)
DT 15
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simu4.sav
XCFI
!COMMAND FILE TO RUN PUMPING SIMULATION #5
!SITE 1 PUMPING AT 1200GPM
!SITE 2 PUMPING AT 1200GPM
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rates
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -115508.02 NODE 97 LEVEL 4
FLUX -115508.02 NODE 97 LEVEL 5
FLUX -231016.04 NODE 23 LEVEL 5
!set the time step for the simulation (in days)
DT 15
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simu5.sav
XCFI
!COMMAND FILE TO RUN PUMPING SIMULATION #6
!SITE 1 PUMPING AT 600GPM
!SITE 2 PUMPING AT 600GPM
!restore the base case save file
REST FINAL.SAV
!set the recharge to 0
RECH 0
!establish the appropriate pumping rates
!node 97 corresponds to site 1
!node 23 corresponds to site 2
FLUX -57754.01 NODE 97 LEVEL 4
FLUX -57754.01 NODE 97 LEVEL 5
FLUX -115508.02 NODE 23 LEVEL 5
!set the time step for the simulation (in days)
DT 15
!set the simulation's duration time (in days)
GOTI 180
!save to new .sav file
SAVE simu6.sav
XCFI