United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
&EPA CZAEM User's
EPA/600/R-94/I 74
September 1994
Modeling Capture
Zones of Ground-Water
Wells Using Analytic
Elements
-------
EPA/600/R-94/174
September 1994
CZAEM USER'S GUIDE
MODELING CAPTURE ZONES OF GROUND-WATER WELLS USING ANALYTIC ELEMENTS
by
O.D.L. Strack - Principal Investigator
E.I. Anderson
M. Bakker
W.C. Olsen
J.C. Panda
R.W. Pennings
D.R. Steward
University of Minnesota
Minneapolis, Minnesota 55455
CR-818029
Project Officer
Stephen R. Kraemer
Processes and Systems Research Division
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
This study was conducted in cooperation with
Indiana University
School of Public and Environmental Affairs
Bloomington, Indiana 47405
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
Printed on Recycled Paper
-------
NOTICE
The work presented in this document has been funded wholly (or in part) by the U.S. Envi-
ronmental Protection Agency under cooperative agreement CR-818029 to Indiana University. It
has been subjected to Agency review and approved for publication. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use.
All research projects making conclusions or recommendations based on environmentally related
measurements and funded by the U.S. Environmental Protection Agency are required to participate
in the Agency Quality Assurance Program. This project did not involve environmentally related
measurements and did not involve a Quality Assurance Plan.
The material introduced in the User's Guide should be fully understood prior to the application
of the computer program CZAEM to field problems. Both the creation of the conceptual aquifer
model and the interpretation of this program's output require an understanding of the Analytic
Element Method and its implementation in CZAEM Interpretation of the output generated by
the CZAEM program is the sole responsibility of the user.
-------
FOREWORD
EPA is charged by Congress to protect the Nation's land, air, and water systems. Under a
mandate of national environmental laws focused on air and water quality, solid waste management,
and the control of toxic substances, pesticides, noise, and radiation, the Agency strives to formulate
and implement actions which lead to a compatible balance between human activities and the ability
of natural systems to support and nurture life.
The Robert S. Kerr Environmental Research Laboratory is the Agency's center for expertise
for investigation of the soil and subsurface environment. Personnel at the Laboratory are responsi-
ble for management of research programs to: (a) determine the fate, transport, and transformation
rates of pollutants in the soil, the unsaturated and the saturated zones of the subsurface environ-
ment; (b) define the processes to be used in characterizing the soil and subsurface environments
as a receptor of pollutants; (c) develop techniques for predicting the effect of pollutants on ground
water, soil, and indigenous organisms; and (d) define and demonstrate the applicability of using
natural processes, indigenous to the soil and subsurface environment, for the protection of this
resource.
The Capture Zone Analytic Element Model CZAEM is a practical, PC-based ground-water
analysis tool that allows for the definition of the areas contributing recharge to pumping wells,
including the influence of rivers, streams, and other surface water bodies. The solution is based on
a new technique for ground-water modeling known as the analytic element method. Capture zone
definition is fundamental in the design of remediation systems for source containment or pump-
and-treat of contaminated ground water, and also in the delineation of protection areas around
drinking water wells.
linton W. Hall, Director
Robert S. Kerr Environmental Research Laboratory
111
-------
ABSTRACT
The computer program CZAEM is designed for elementary capture zone analysis, and is based
on the analytic element method. CZAEM is applicable to confined and/or unconfined flow in
shallow aquifers; the Dupuit-Forchheimer assumption is adopted. CZAEM supports the following
analytic elements: uniform flow, uniform infiltration over a circular area, wells, and line-sinks. The
line-sinks can be used to simulate streams and the boundaries of lakes and rivers.
The program will generate and plot the envelopes of capture zones, the boundaries of capture
zones corresponding to different times, dividing streamlines including stagnation points, stream-
lines, and piezometric contours.
A tutorial is provided to introduce the user to CZAEM and consists of two parts, each with
three examples. Part A is concerned with introducing the user to the primary capabilities of
the program along with elementary modeling techniques. Part B is aimed at advanced modeling
techniques and commands. It is explained at the end of part B how to obtain hardcopy output
from the program.
IV
-------
TABLE OF CONTENTS
Notice ii
Foreword iii
Abstract iv
Figures vii
Acknowledgment viii
Introduction 1
Background 1
The Analytic Element Method 1
The Computer Program CZAEM 2
Installation 3
CZAEM TUTORIAL PART A
Example 1 Uniform Flow with a Well 4
Entering the program CZAEM 5
Entering aquifer data 6
Solution and generation of contour plots 8
Entering and analyzing the proposed well 10
Exiting the program CZAEM 12
Example 2 Well near a River 12
Entering line-sinks 13
calculating the head at any point 15
Entering the well 16
Saving a solution 17
Influence of the reference point 17
Determining a well's water source using pathlines 18
Example 3 Critical Pumping Level for a Well 21
Creating capture zones 21
Interpretation of Figure 3.1 24
Determining a well's water source using capture zones 24
Summary of Part A 26
CZAEM TUTORIAL - PART B
Example 4 Contaminant Pumpout System 29
Obtaining results using CHECK 31
Determining capture zones for multiple wells 35
Well water travel times 36
Moving wells in graphics mode 38
Example 5 Data Manipulation and Model Refinement 40
Using input files 40
Saving grid files 41
Comparing grids 42
Obtaining results using the cursor in CAPZONE 44
Validity of Solutions 15
-------
Example 6 Data File and Graphics Control 45
Accessing multiple data files contiguously 45
Entering rainfall 46
Window manipulation and saving capture zone and time zone boundaries 46
Obtaining a hardcopy of graphical output 49
References 52
Command Summary 53
VI
-------
FIGURES
Figure 1.1 Site map for Example 1 4
Figure 1.2 Conceptual model of the aquifer 5
Figure 1.3 Contour plot of the phreatic surface 9
Figure 1.4 Piezometric contours with the well present 11
Figure 1.5 The water beneath the field does not enter the well 12
Figure 2.1 Site map for Example 2 13
Figure 2.2 Conceptual model of the aquifer 14
Figure 2.3 Plot of piezometric contours, well not present 16
Figure 2.4 Contours with the well present, reference point at (-2000, 4000) 18
Figure 2.5 Contours with the well present, reference point at (1,1) 19
Figure 2.6 Contours with the well present, reference point at (-2000, 5000) 20
Figure 2.7 Several pathlines from the well generated by < WGENERATE > begin at the
well and end at the line-sink, showing that the well does capture river water 21
Figure 3.1 Capture zones generated for a well discharge of 1500 mVday 23
Figure 3.2 Capture zones generated for a well discharge of 1000 mVday 25
Figure 3.3 Capture zones generated for a well discharge of 970 mVday 27
Figure 3.4 Capture zones generated for a well discharge of 990 mVday 27
Figure 4.1 Site map for Example 4 29
Figure 4.2 Conceptual model of the aquifer 30
Figure 4.3 Existing conditions' uniform flow with reference head of 129.84 meters at
(-750 -875) 31
Figure 4.4 Existing conditions, uniform flow with reference head of 133.586 meters at
(-2000 -2000) 33
Figure 4.5 Contours with the well present 35
Figure 4.6 Subzones drawn for the well 36
Figure 4.7 Subzone curves for both wells 37
Figure 4.8 Twenty year time zones for Wells 1 and 2 38
Figure 4.9 Twenty year time zones for the fronts, with a front velocity factor of 1.1 39
Figure 5.1 Case of Example 3 with refined line-sinks 43
Figure 5.2 Refined line-sink grid minus the original line-sink grid 44
Figure 6.1 Model of existing conditions (plot; d 10) 46
Figure 6.2 Model of proposed conditions (plot; 780 5) 47
Figure 6.3 Well-field subzones 49
vn
-------
ACKNOWLEDGMENTS
The authors express their appreciation to the volunteer group of "guinea pigs" who did the
beta testing of the code. The code and documentation were much improved after technical reviews
provided by Mr. Paul van der Heijde, Dr. Jeffrey Johnson, and Dr. Randall Charbeneau. Ms.
Chursey Fountain provided editorial review of the documentation.
This report was typeset by MS-TftX, the TgXnacro system of the American Mathematical
Society.
vin
-------
INTRODUCTION
The Wellhead Analytic Element Model (WhAEM) package, a capture zone delineation tool for
wellhead protection and pollution containment, is the result of a cooperative agreement between the
USEPA, the Indiana University at Bloomington, and the University of Minnesota at Minneapolis.
The package consists of two executable: the first contains the graphical pre-processor GAEP along
with a manual describing its use; the second contains the computer program CZAEM Capture
Zone Analytic Element Model. The latter program's intended use is for the modeling of problems
where the flow is generated by few (say 50) features (small-scale problems), either together with
GAEP, or by itself. The integrated WhAEM package is described in USEPA (1994).
The presented tutorial deals with the use of CZAEM as a stand-alone program, along with
some applications to elementary problems.
BACKGROUND
The objective of the project was to develop algorithms for determining, in relatively simple
settings, the envelopes of capture zones of wells. The capture zone envelope of a well contains
all water that will reach the well, given an infinite time period. Capture zones are divided into
sub-capture zones (called subzones in the program), according to the source of the water in the
zone (for example, a section of a river or a recharge well. ) Also of interest are capture zones for a
certain time period, called time zones in the programs. The capture zone for a given time period
of length / is defined as that portion of a capture zone containing all water that reaches the well
within a time period of /. As far as the authors know, the program CZAEM is the first program
that fully computes and displays the boundaries of the capture zone envelope, subzones, and time
zones, including dividing streamlines and stagnation points, for any well in the flowfield.
CZAEM is intended primarily for small-scale applications that can be handled with little
effort and without the need for an advanced computer model. It will generate useful information
for such problems, mostly in graphical form, and hopefully will increase the understanding of the
shape and extent of capture zones. As CZAEM was not written with complex problems in mind,
it is recommended that applications be limited to relatively simple problems. Complex problems
should be dealt with by professionals with access to more powerful computer programs. This
document contains a brief description of the method on which CZAEM is based, the analytic
element method, a brief description of the program, and the tutorial.
THE ANALYTIC ELEMENT METHOD
The analytic element method is based on the superposition of analytic functions. Each of these
functions satisfies the fundamental equations for ground-water flow exactly and has properties that
make it suitable to model a certain feature of the aquifer. The method is described in detail by
Strack (1989).
Although simple in principle, the analytic element method has grown into a complex framework
of many specially developed functions, eliminating most of the limitations that used to be associated
with analytical models. The analytic element method differs fundamentally from most of the
classical numerical techniques. Important differences are:
1. The aquifer is unbounded in the horizontal plane.
2. The solution is analytical, and therefore no interpolation is required for computing heads or
velocities. This allows the user to create contour plots and streamlines for any part of the
aquifer, varying in size from several square feet to hundreds of square miles.
1
-------
3. There is no numerical dispersion. Inaccuracies, for example in capture zone boundaries, are
due solely to approximations made in the conceptual model and its implementation in the
program.
The application of the method in CZAEM is elementary, and contains only a few analytic
elements. These elements can be used to simulate river boundaries, streams, lakes, wells, uniform
flow, and uniform infiltration over a circular area. The elements used to model river boundaries,
streams, and lakes are called line-sinks. Line-sinks are mathematical functions designed such that
they simulate a constant rate of extraction along a line between the end points of the line-sink.
The line-sinks may be used to model flow from a stream into an aquifer, with the ground-
water table below the stream bottom. In this case the strength of the line-sink (defined as the
extraction rate per unit length) can be estimated from the head in the stream and the resistivity
of the stream bottom. The stream is then divided into sections, chosen such that the infiltration
approximates the computed infiltration rate of the stream.
Another application of line-sinks is to model constant-head boundaries of rivers, lakes, or
streams. In this application, the model is approximate in that the program computes the strength
of each line-sink section to match the value of head entered. A fine subdivision in line-sink
segments will render a better approximation of the real extraction rate along the stream than a
coarse one.
The well function is used to model wells with either given head or given discharge. The
solution generated by these well functions is accurate, even in the neighborhood of the well, as
there is no numerical discretization.
The uniform flow function adds a uniform component to the far-field (this is the flow pattern
far away from the area modeled.) Finally, the function for radial infiltration (called the rain
function in the program) may be used to simulate uniform infiltration inside a circle.
THE COMPUTER PROGRAM CZAEM
The computer program CZAEM is an enhanced version of the computer program SLWL
(Strack, 1989) with the capability added to generate capture zones of wells. The program is fully
modular; the main modules are the following:
1. AQUIFER, for the input of aquifer data,
2. GIVEN, for the input of uniform flow and rain.
3. REFERENCE, for the input of the head at one point in the aquifer.
4. WELL, for the input and implementation of wells.
5. LINESINK, for the input and implementation of line-sinks.
6. GRID, for the generation of grids of values of piezometric heads, to be contoured.
7. PLOT, for the generation of piezometric contours.
8. TRACE, for the generation of streamlines.
9. CAPZONE, for the generation of capture zones.
10. CURSOR, for the retrieval of data using graphical input.
11. CHECK, for the retrieval of data using keyboard input.
12. IO, for the binary input and output of solutions
All of these modules, with the exception of CAPZONE, existed prior to the present project.
The module CAPZONE is written in FORTRAN. The listing of this module is available separately
-------
from the USEPA. In order to facilitate implementation in other computer programs, it is indicated
in the listing where and how functions providing necessary data to the module are to be called.
The user interface of CZAEM (modeled after SLWL) is a command-line interface. Such an
interface differs from many of the current mouse-driven interfaces. It has the advantage of flexibility,
but requires a longer learning period. Prospective users of CZAEM unfamiliar with the analytic
element method or with the command-line interface of SLWL are urged to take the time to follow
the examples in the tutorial. These examples are designed specifically to guide the user through
the use of CZAEM progressively introducing several aspects of the program. A study of the first
three examples is considered pre-requisite (preferably by hands-on application) before application
of CZAEM The final two examples are used to introduce some of the more advanced features of
the program.
In order to simplify the user interface, the command lines and menus are reduced to contain
only the commands used in this tutorial. Other commands, useful for more advanced applications,
are available but are left out of the menus. All commands, however, are listed in the help files
provided with the program. Everywhere in CZAEM the user may obtain a brief help summary for
a command by typing the command word in the current menu followed by a space and a question
mark. A list of the commands that are available in a module will be displayed by entering the
command word help.
INSTALLATION
An installation batch file called czinst.bat is supplied with the program CZAEM To install
the program onto a hard drive, change to the disk drive containing the diskette and type
czinst a c
where a represents the disk drive containing the diskette and c represents the hard drive destina-
t ion. Further information regarding installation of the program and supported printer devices is
contained in the file read.me. It is recommended to read this file prior to installation.
-------
CZAEM TUTORIAL - PART A
EXAMPLE 1. UNIFORM FLOW WITH A WELL
A fanner wishes to engage in organic farming to complement his regular farming practices. In
order to comply with regulations, he must irrigate his organic crops with ground water that does
not contain the chemicals that are placed on his other fields. It is estimated that a minimum of 60
cubic meters of water per day is necessary to make the venture profitable. Therefore the following
is required:
1. Field characterization to determine aquifer parameters.
2, A model to represent existing flow conditions.
3. An analysis of flow conditions due to the addition of the irrigation well.
Four monitoring wells were installed to determine the aquifer parameters (Figure 1.1). Soil
tests indicate that the permeability and porosity are 6 m/day and 0.3, respectively. Surface
elevations are relatively uniform at 250 m above sea level. Boring logs show the distance to a
confining soil layer from the surface to be 100 m. These values, including ground-water elevations
from the monitoring wells, allow for a model conceptualization of the aquifer (Figure 1.2). It is
necessary to enter all values in consistent length and time measurements (i. e., if the discharge were
given in units of gallons per minute, it would have to be converted to cubic meters per day prior
to entering). The next step is to implement this representation in CZAEM
Monitoring Well 1
= 200.5 m
(-350,350)
(-150,350)
(-350,150)
(-150,150)
Monitoring Well 2
4>i = 200.0 m
•
(250,250)
Proposed Well
Q = 60 m3/day
(-250, -250)
•
Monitoring Well 3
z = 200.5 m
(250, -250)
•
Monitoring Well 4
^4 = 200.0 m
Figure 1.1 Site map for Example 1.
4
-------
MW# 1
i = 200.5 m
100m
ELEV = 250 m
Q = 60 m3/day
MW#2
2 = 200.0 m
permeability = 6 m/day
porosity =0.3
250m
• 250 m •
Well radius = 0.15m
Figure 1.2 Conceptual model of the aquifer.
Entering the program CZAEM
Change to the CZAEM directory, which contains the executable file czaem.exe.
A:\ >D:
D:\ >CD CZAEM
Where D: represents the disk drive where CZAEM is installed. Enter CZAEM by typing
D: \ CZAEM>CZAEM
Before entering any data, a brief description of CZAEM'S structure is in order. On your screen
is the MAIN menu of command words
\\\ Module-MAIN MENU Level'O Routine*INPUT ///
ENTER COMMAND WORD FOLLOWED BY ? FOR BRIEF HELP FROM ANY MENU
[(X1.Y1.X2,Y2)///]
-------
followed by an enter. Only the initial characters of the command words need to be entered, as
many as required to be unique (four is the maximum you may have to enter, but you can enter
more if you wish). In this tutorial, the command is commonly abbreviated
ret
Throughout this first problem, the full names of the bracketed terms shall be typed out; in subse-
quent examples in this tutorial, only the significant letters shall be used.
Entering aquifer data.
We enter the aquifer parameters in the module AQUIFER. Enter the module with the com-
mand . Note that all data must be input with consistent units. Enter
aquifer
CZAEM responds with
\\\ Module-AQUIFER Level-1 Routine=INPUT ///
(PERM)(THICK)(ELEVATION) (POROSITY)
The permeability and porosity may be entered directly:
permeability 6
porosity 0.3
Note that the numbers and letters need only be separated by a space, This is also true for
commands that require two values or more. In addition, values may be entered using exponential
form (e.g., 0.6el and 300e-4).
The command requires as the argument the actual vertical extent of the
aquifer (Figure 1.2). is the elevation of the bottom of the aquifer above sea level (or any
datum you chose). Enter
thickness 100
base 150
Note that BASE and POROSITY have default values of 0 and 0.3, respectively. Default values
are used if the user does not enter parameter values. To return to the MAIN module, enter
return
CZAEM will respond by displaying the MAIN menu
\\\ ModuIe=MAIN MENU Levei^O Routine=IriFUT ///
ENTER COMMAND WORD FOLLOWED BY ? FOR BRIEF HELP FROM ANY MENU
[(X1,Y1,X2,Y2)///]
-------
This module is where certain elements with given strengths (i.e., known discharges) are defined.
The only element we can calculate at this point is uniform flow, or UNIFLOW. This value represents
the amount of ground water flowing per unit length of aquifer. To compute the uniform flow
components, use three of the four monitoring well water elevations and locations in conjunction
with the Dupuit formulae for unconfined flow
- v3)
where
Qx = magnitude of flow in the x-direction
Qy = magnitude of flow in the y-direction
Qa = magnitude of flow in the direction of angle a
k = permeability
i = head at location (ii,j/i)
^2 = head at location (3:2,2/2)
03 = head at location (0:3,^3)
b = base elevation
a = angle between direction of flow and the x axis (0 to 360°)
(see Strack [1989]). UNIFLOW consists of a constant discharge per unit width of aquifer (mag-
nitude) and a direction (angle). The magnitude is the resultant of Q^and Qrand the angle is
measured from O to 360 degrees where O is the positive x-axis on the standard coordinate system
(O is due East). Here we have the following:
6[(200.5 - ISO)2 - (200 - ISO)2]
Qx ~ 2[250-(-250)J ~
_ 6[(200 - ISO)2 - (200 - ISO)2]
Qy ~ 2[250 - (-250)]
\Qa\ = \/0.30152 + O2 = 0.3015
To enter, type:
UNIFLOW 0.3015 0
Note that the term angle in the command line is surrounded by [ ]; this indicates that it is an
optional value and has a default. The default value is 0. Therefore, you could have just typed
UNIFLOW 0.3015. Return to the MAIN module:
7
-------
The amount of information entered thus far can adequately describe the shape of the phreatic
surface. We must fix the elevation of that surface at some point by specifying a known head at a
known location. We shall use monitoring well number 3 as our reference point as follows
reference
CZAEM responds with
(X, Y,REFERENCE HEAD)
You must enter the coordinates and ground-water elevation at the reference point. From Figure
1.1, enter
-250 -250 200.5
More thought must go into the choice of the reference point than appears in this first example.
Its effect is to control the amount of water that comes from infinity (i.e., very far away). When
fixing the reference point, the value of head at this location shall remain unchanged no matter what
other elements are placed in proximity. This issue will become more clear in following examples.
Note for now that a reference point is required to solve any ground-water flow problem with
CZAEM
Solution and generation of contour plots.
The final step in completing the model of existing flow conditions is to solve for all unknowns.
To do this, enter
CZAEM responds with
ITERATION 1
SOLVING 1 EQUATIONS
10 .
Head and discharge may now be explicitly determined everywhere. We will make a contour
plot of the head on the screen. Our region, or window, shall be four square kilometers centered
around the proposed well. Enter the coordinates of the lower left- and upper right-hand comers
as follows:
window -2000 -2000 2000 2000
We choose the number of points, distributed uniformly within this window, at which to compute
heads. Higher numbers yield higher resolution from the contouring routine used for interpolation.
This grid should not be confused with the mesh in a numerical technique such as finite elements
or finite differences. It is best to specify the grid with values between 20 and 50 (maximum 150).
Enter
grid 50
CZAEM responds with
10
20
30
40
50
60 .
-------
A beep indicates completion of calculations. To view the flow field, enter
plot
Note that a solution, window, and grid must be specified prior to any plot. Plot options and limits
are displayed
EFAULT [NUMBER OF LEVELS] AYOUT
(MIN LEVEL [INCRENENT {><>}] [MAX LEVEL]
(MAX LEVEL [DECREMENT { [<0}] [MIN LEVEL]
MIN. LEVEL= 1.9820S2+0 MAX. LEVEL= 2.022123E+02
At this time, we are not interested in specific contours, so we use the default option and ask for
twenty levels to be plotted between the extreme values. Enter
d 20
CZAEM responds with
START LEVEL 1.983000E+02 INCREMENT 2.000000E-01 PRESS ENTER
This shows the value of head at which contouring starts and the contour interval. When using
default, the contours will be drawn from lower to higher head due to the positive increment. Press
[enter] to view the flow field.
[enter]
Figure 1.3 Contour plot of the phreatic surface.
The plot has straight contours as we move in the direction of flow. The results reflect uniform
flow. Press [enter] to return to the MAIN command line after viewing the model of existing flow
conditions.
-------
Entering and analyzing the proposed well.
Enter the module WELL from MAIN
CZAEM responds with
\\\ Module=WELL Level = l Routine=INPUT ///
The problem specifies a given discharge. Figure 1.1 indicates that the well is placed at the
center of the coordinate system and Figure 1.2 shows the well to have a radius of 0.15 m. We wish
to enter a well with a known discharge.
given
CZAEM responds with
\\\ Module=WELL Level=l Routine=WELL GIVEN ///
(X,Y,DISCHARGE) [RADIUS][[LABEL]]
Following the instructions of the command line, enter
0 0 60 0.15
return
After entering a new element (the well), we must find a new solution, and again grid and plot
to see the effects. We shall also zoom in on the area of interest. It is important to enter the new
window size prior to gridding, otherwise the plot for the previous window will be placed over the
new window giving erroneous results.
solve
window -500 -500 500 500
grid 50
plot
d 20
[enter]
Notice the drawdown around the well (Figure 1.4). Press [enter] to return to the MAIN
command line, and enter the module TRACE
[enter]
trace
CZAEM responds with the command line
\\\ Module=TRACE; Level=l Routine=INPUT ///
[ (xl,Yl,x2,Y2)// /] [TOLERANCE ] (/)
-------
Figure 1.4 Piezometric contours with the well present,
Assuming that the mass of the chemicals applied to the crops is negligible with respect to the
original flow, any streamlines passing under the crops represents the path of chemicals through the
aquifer. It would be beneficial to identify the boundary of the crops in question. To draw a map
of the field boundary, return to the MAIN module and enter the module MAP
map
CZAEM responds with the command line
\\\ Module=MAP Level = l Routine=INPUT ///
(ON/OFF)
To view the map on the screen with each plot, set the option on
plot on
We draw the crop boundary using the command . Start at one corner of the field and
draw a line from comer to comer, completing the drawing by entering the first corner again. MAP
will prompt for each set of coordinates.
curve
-350 150
-350 350
-150 350
-150 150
-350 150
return
Return to the module TRACE and move the cursor along the boundary to see if any chemically
influenced water enters the well (Figure 1.5).
11
-------
Figure 1.5 The water beneath the field does not enter the well.
Exiting the program CZAEM
To exit CZAEM return to the MAIN module and type
stop
This returns control to DOS.
EXAMPLE 2. WELL NEAR A RIVER
A high capacity well with a diameter of 0.6 m and a pumping rate of 1500 mVday is proposed
to be placed near a river at a fixed location. We are asked to determine whether or not the well will
capture river water. The hydrogeologic information is shown in Figures 2.1 and 2.2. The aquifer
parameters are the following: permeability 5 m/day, thickness 50 m, base elevation 0 m, porosity
0.25, uniform flow 0.5 m3/(m day) at 30°. In addition, piezometric head measurements are known
at different points along the river.
In CZAEM enter the following data using consistent units from the MAIN command line
aqui
perm 5
thick 50
base 0
poro 0.25
ret
given
uni 0.5 30
ret
12
-------
32m
(-1500,1500)
(-600.1300)
,33m
(500,200)
Uniform Flow
Qa = 0.5 m3/(m day)
Proposed Well
Q = 1500 m3/day
(500, -800)
(800,-1
39m
(1100,-1000)
.40 m
(1500,-1800)
Figure 2.1 Site map for Example 2.
Entering line-sinks.
A river is simulated in CZAEM by a series of line-elements called line-sinks. We first need
to break a river into straight line segments. Each line segment will be entered in the model as a
line-sink. River discharge into or out of the aquifer is assumed to be constant along each segment
The discharge is either known a priori or is calculated by specifying the head at the center of the
line-sink resulting in given or head-specified line-sinks, respectively. A given line-sink extracts
a fixed amount of water per unit length of line-sink without placing any restriction on the head
distribution along the line-sink; a head-specified line-sink also extracts a fixed amount per unit
length but creates a control point at its center which makes it possible to solve for the discharge
such that the head at the control point equals that entered. Given line-sinks are entered in
a similar fashion as wells. The input of head-specified line-sinks is outlined below. Enter the
module LINESINK
CZAEM responds with
13
-------
Uniform Flow
Qa = 0.5 m3/(m day)
a = 30°
•=1500
50m
permeability = 5 m/day
porosity = 0.25
ELEV = 0 m
Well radius = 0.10 m
Figure 2.2 Conceptual model of the aquifer.
\\\ Module=LINE-SINK Level=l Routine=INPUT
[/] [TOL]
Line-sinks with known strengths are entered through the command , and those with
known heads through the command . We have head-specified line-sinks; type
head
CZAEM responds with
\\\ Module=LINE-SINK Level=l Routine=LINE-SINK
(XI,Y1,X2,Y2,HEAD)[[LABEL]]
CZAEM requests the coordinates of the starting point (XI,Yl), the coordinates of the endpoint
(X2,Y2), and the head at the midpoint of each line-sink (HEAD), in that order. For clarity, start
at any one end of a series of contiguous line-sinks and enter them in order of occurrence. We start
from the north end of the river and enter the first line-sink
-1500 1500 -600 1300 32
After a line-sink is entered, CZAEM prompts for another line-sink.
\\\ Module=LINE-SINK Level=l Routine=LINE-SINK HEAD ///
(XI,Yl, X2, Y2) , HEAD)[[LABEL]]
Although the command line is not displayed, it is still active, and we may at any time enter
to begin a head specified line-sink, to see the command line, or
to return to the MAIN module. Enter the remaining line-sinks and return to the
MAIN module
-600
-200
1300
900
-200
200
900 33
500 34
14
-------
200 500 500 200 35
500 200 500 -800 37.5
500 -800 800 -1000 38
800 -1000 1100 -1000 39
1100 -1000 1500 -1800 40
ret
We have returned to the MAIN module. A visual check of our data entries is possible with
the command . In this case we choose a window with a lower left corner at (-1500,
-1500) and the upper right corner at (1500,1500).
window -1500 -1500 1500 1500
To view a layout of all the elements, type
layout
When finished viewing, press [enter] to return to MAIN.
The last piece of information required is the reference point. In this example the reference
point is used as a calibrating parameter, rather than as a point of given location and head as in
Example 1. Analytic element models such as CZAEM do not require a bounded model but deal
with an infinite domain. The flow of water from far away (infinity) can be used to approximate
physical sources and sinks that are present in the real aquifers but not represented in the model
explicitly. This flow of water is regulated via the head specified at the reference point. The more
the physical sources or sinks are included in the model the less the influence of the reference point.
Since the reference point is often used to approximate complex features that are far away and
left out of the model, its use as a calibration tool requires some experience with analytic element
models. The reference point should be chosen far enough away from the area of interest that the
head is not expected to change appreciably due to the introduction of any new element (e.g., a
well). We first use a point with coordinates (-2000,4000) and a head of 40 m as the reference point.
ref
-2000 4000 40
Solve, grid, and plot the solution (Figure 2.3).
solve
grid 50
plot
d
[enter]
We assume for now that the model closely matches observed heads.
Calculating the head at any point.
We can determine the head at any point in the aquifer through the module CHECK. We type
check
CZAEM responds with
\\\ Module = CHECK Level = l Rout ine= INPUT ///
< AQUI FEE >< GI VENx REFERENCE >< WELL XL INS S INK >
(X,Y)(X,Y)
This is the CHECK module menu. Enter
head 1 1
CZAEM responds with
15
-------
Figure 2.3 Plot of piezometric contours, well not present,
X Y HEAD
l.OOOOOOE+00 l.OOOOOOE+00 3.718284E+01
followed by the command line. Enter
head -2000 5000
CZAEM responds with
x Y HEAD
-2.00000000E+03 5.000000E+03 3.975401E+01
Note the heads at these two points for future use. With only uniform flow present, entering
either of these heads at their respective locations as the REFERENCE would result in identical
solutions. Return to the MAIN module.
Entering the well.
We now solve the problem with the original reference point and the well present. First, we
will reduce the window size so that we may examine more closely the changes due to the well.
window -1000 -1000 1000 1000
To enter the well, type
well
given
0 0 1500 0.3
ret
16
-------
Since the well affects the flow field, we must solve again
solve
Saving a solution.
It is often desirable to save a solution for later use. The command is used for that
purpose and stores all current information in a binary file. We save this solution for retrieval later;
enter
CZAEM responds with
OOLOTIOMXGRIDXBOTHXRETOHIO
To select SOLUTION, type
sol
CZAEM will request a file name
{to abort}
Enter the filename
ex2.sol
If the file ex2. soi does not already exist, CZAEM responds with
SOLUTION FILE HAS BEEN WRITTEN
PROBLEM: UNNAMED
If the file already exists, CZAEM will offer you a prompt to overwrite the file or abort the command.
The name and extension are arbitrary. The directory under which the file ex2.soi is placed is
CZAEM unless otherwise specified.
In order to view the new solution, enter
grid 50
plot
d
[enter]
Observe the changes in the piezometric contours due to the well (Figure 2.4). Press [enter] to
return to the MAIN module.
Influence of the reference point.
We will now examine the effect of the reference point on the solution. First choose the reference
point at (1,1) with a head of 37.1828 (these are values that we determined using CHECK).
ref
1 1 37.1828
solve
grid 50
plot
34 4
[enter]
This plot is shown in Figure 2.5. Comparing Figures 2.4 and 2.5, we see that the influence of the
reference point on the piezometric contours is major, because we entered a well near the reference
point.
17
-------
Figure 2.4 Contours with the well present, reference point at (-2000, 4000).
Now we see what happens when we enter (-2000,5000) as our reference point with a head of
39.7540 (the second point determined in CHECK)
ref
-2000 5000 39.7540
solve
grid 50
plot
26 2
[enter]
This plot is reproduced in Figure 2.6 and is nearly identical to the one in Figure 2.4 even though
the reference points are different; the influence of the well is insignificant at both reference points.
This confirms that the reference point must always be chosen sufficiently far away so that elements
in the model do not influence the head at the reference point significantly.
Determining a well's water source using pathlines
We are now prepared to answer the question: will the well capture the river water? We retrieve
the original solution and data saved in the file ex2.soi by the use of the command .
From the MAIN command line, enter
read
CZAEM responds with
18
-------
Figure 2.5 Contours with the well present, reference point at (I, 1).
Enter
solution
CZAEM responds with
PLEASE ENTER FILENAME; TO ABORT
Enter
ex2.sol
CZAEM responds with
SOLUTION FILE HAS BEEN READ
PROBLEM: UNNAMED
CZAEM has read in the binary file with all the elements entered at the time of saving. Since
the problem was solved prior to saving, the parameter values have also been read in. CZAEM
returns to the MAIN menu after reading in the file.
There are several ways to determine whether the well draws river water in CZAEM here we
shall use the technique of tracing the particle pathlines in a backward fashion starting at the well.
Enter TRACE by typing
Streamlines are traced in the direction of flow by default. We set it to backward tracing with the
command . Backward tracing from the well is achieved by the command
19
-------
Figure 2.6 Contours with the well present, reference point at (-2000, 5000).
. Note that to return to forward tracing one must type .
We must first enter PLOT, or LAYOUT; here we choose PLOT as it will produce the piezometric
contours. We enter PLOT exactly as we" did from the MAIN menu.
plot
d
[enter]
CZAEM plots the picture on the screen and gives the following menu:
\\\ Module=TRACE; Level=l Routine=INPUT ///
[ELEVATION] []
(# LINES) [ELEVATION]
{TO BACKSPACE, PRESS < }
The cursor appears at the center of the screen (in this case directly over the well).
With the cursor positioned at the well, first switch backward tracing on
backward on
Now the command may be used. This command has one required parameter
and one optional parameter. The required parameter is the number of pathlines generated from the
well and the optional parameter is the vertical elevation in the well from which they will originate.
The default elevation is the bottom of the aquifer. We choose the number of traces to be 20 by
typing
wgen 2 0
You will see pathlines starting from the well and going back toward their original source (Figure
2.7). The well is seen to be drawing some of its water from the river. We conclude that the
20
-------
proposed discharge is not feasible without drawing river water. To return to the MAIN menu and
exit CZAEM enter
ret
stop
Figure 2.7 Several pathlines from the well generated by < WGENERATE > begin at
the well and end at the line-sank, showing that the well does capture river
water.
EXAMPLE 3. CRITICAL PUMPING LEVEL FOR A WELL
This example expands on the problem presented in Example 2 and introduces the module
CAPZONE. We will determine the critical pumping level of the well, defined here as the largest
discharge not capturing river water. In Example 2, the well is entered with a discharge of 1500
mVday, and is drawing water from the river. We will use to view the current
solution, then adjust the well discharge until the critical level is reached.
Since the current problem has few elements, it will be sufficient to use from
the outset to evaluate each well pumping level. For larger problems, it may be more efficient to
use or for the first iterations.
Creating capture zones.
Begin by entering CZAEM and reading in the binary file describing Example 2. From the
MAIN command line enter
read
solution
ex2.sol
21
-------
The binary file with all elements entered in Example 2 and the parameter values determined by
has been read in. Enter
grid 50
trace
CZAEM responds with
\\\ Module=TRACE; Level=l Routine=INPUT ///
[(XI,Y1,X2,Y2)///][TOLLERANCE](/)
We enter the module CAPZONE from within TRACE and type
CZAEM responds with
EFAULT (NUMBER OF LEVELS] AYOUT
(MIN LEVEL [INCREMENT {>0}] [MAX LEVEL]
(MAX LEVEL [DECREMENT {<0}] [MIN LEVEL]
MIN. LEVEL= 2,506159E+01 MAX. LEVEL= 4.225655E+01
We can enter the desired levels, request default levels , or just get a layout . For this
example enter
d
[enter]
We are now in the CAPZONE module, and the menu is
\\\ Module=CAPUTRE ZONE; Level=l Routine=INPUT ///
[ (XI, Y1,X2, Y2) ///] (LINES) [[VELOCITY FACTOR]/](# LINES)[COLOR1][2][3]
(FILE)(FILE){TO BACKSPACE, PRESS < }
CZAEM is in graphics mode, and the backspace key is no longer active. It is replaced by the
less-than sign (<). We are about to let CZAEM determine the capture zone envelopes for the well
and streamlines dividing the capture zone into subzones. Before discussing the meaning of these
curves, we will generate them on the screen. Move the cursor over the well and enter the command
. Since the well is centered in the current window and therefore already coincides
with the cursor, we enter
CZAEM responds with
UNCONFINED: X,Y, PHREATIC SURFACE 4.066071E-02 4.066071E-02 2.551642E+01
CALCULATING SUBZONES PHASE 1: CREATING INITIAL PATHLINES FROM THE WELL
10
20
30 .
CALCULATING SUBZONES PHASE 2: DETERMINING LOCATION OF STAGNATION POINTS
10
20
30 .
CALCULATING SUBZONES PHASE 3: FILLING SUBZONE BUFFERS
10
22
-------
Figure 3.1 Capture zones generated for a well discharge of 1500 nf/day.
CZAEM computes the capture zone envelope curves and plots them along with all dividing stream-
lines (Figure 3.1).
Dividing streamlines either pass through stagnation points (points where no flow occurs in
any direction) and end at the well, or separate unique source areas for the selected well. The
envelope curves bound the entire area supplying water to the well. CZAEM distinguishes each
individual element (e. g., a line-sink in a river stretch) as a unique source of water. CZAEM's
23
-------
search for dividing streamlines, envelope curves, and distinct sources terminates at the current
window boundary. In order to obtain meaningful results within CAPZONE, the window must be
chosen large enough to include all of the important sources and the stagnation points.
The window boundary is identified by CZAEM as the source of any water entering the well
originating from far away.
Interpretation of Figure 3.1.
The capture zone envelope for the well consists of envelope curve d, the line-sink, and curve
T> below (Figure 3.1). The source area is divided into two subzones, one whose source is the
window edge, and one whose source is the line-sink. The source areas are delineated by dividing
streamlines B, C, and T>. Curve C and the upper part of curve D are intended to be a single
dividing streamline distinguishing the two source zones, so why are they plotted distinctly rather
than as one? CZAEM tries to plot dividing streamlines starting from stagnation points, which
worked for line B. However, the stagnation point which should have been used for drawing lines C
and T> is discarded by CZAEM because it is within a tolerance distance of the line-sink; CZAEM
plots the nearest dividing streamlines from each source instead. These are separated by 1/200'th
of the well's discharge, which is generally well within modeling precision. The lower part of D is
thus inside of the actual envelope curve by less than 1/200'th of the well's discharge and can be
taken as the working envelope curve.
Determining a well's water source using capture zones.
The amount of water supplied by the river can be found using the command
CZAEM responds with
SOURCE DISTRIBUTION FOR WELL NUMBER 1
SUBZONE NUMBER SOURCE TYPE SOURCE NUMBER % OF WATER
1 WINDOW BOUNDARY 79.5
2 LINE-SINK STRING 5 20.1
PRSSS THE ENTER KEY TO CONTINUE
The current pumping level is too high; 20 percent of the well water originates from the river.
We will next try a pumping level of 1000 mVday. Return to the Well module, reset, enter the well
with the new strength, solve, grid, and regenerate the capture zones. Note that erases
all input data within the current module. This command requires confirmation.
ret
ret
well
reset
yes
given
0 0 1000 0.3
ret
sol
grid 50
tra
cap
d
[enter]
sub
24
-------
Figure 3.2 Capture zones generated for a well discharge of WOO nf/day.
At this pumping level, the capture zone still intersects the river (Figure 3.2). Enter
CZAEM will report that about 1.5 percent of the water is coming from the line-sink. We next
repeat the above procedure to reset the pumping level to 970 m3/day. Enter
ret
ret
well
reset
yes
given
0 0 970 0.2
ret
solve
grid 50
trace
CAPZONE
d
[enter]
sub
At this pumping level, the capture zone just misses the river (Figure 3.3).
Next try a pumping level of 990 mVday. Enter
ret
ret
well
reset
yes
25
-------
given
0 0
ret
solve
grid 50
trace
CAPZONE
d
[enter]
sub
The capture zone boundary now ends at the line-sink (Figure 3.4); The command< SOURCE>
reports that all the water is coming from uniform flow. Enter
What does it mean that the envelope ends at the line-sink but the line-sink is not identified
as a source? Recall that CZAEM determines the contributions from each source with a precision of
1/200'th of the well's discharge; flow from the line-sink must therefore be less than that amount. No
dividing streamlines are drawn to demarcate the source zones since only one source is found. The
envelope curve is drawn from the stagnation point toward the line-sink and stops there because
CZAEM detects the change in flow direction at the line-sink. As in the first plot, there is no
stagnation point recorded at the line-sink, thus the envelope curve is not continued.
We conclude that the critical pumping level is between 970 and 990 mVday. Note that this
solution is based on an oversimplified representation of the river reach supplying water to the well.
In the advanced tutorial lessons (Example 5) we will see that refining the model can change this
estimate. The modeling process normally includes successive refinement of the model until changes
in the results are within modeling accuracy.
SUMMARY OF PART A
In the first three tutorial exercises we have introduced elementary modeling techniques and
the display of capture zones with the following CZAEM commands
AQUIFER:
GIVEN:
REFERENCE
WELL:
LINESINK:
SOLVE
CHECK:
WINDOW:
MAP:
LAYOUT
GRID
PLOT:
LAYOUT
TRACE :
SAVE:
READ:
PERMEABILITY, POROSITY, THICKNESS, BAS:
UNI FLOW
GIVEN
HEAD
HEAD
XI, Yl X2,Y2
CURVE, POINT, PLOT ON
D, L
TRACE
PLOT: WGENERATE, BACKWARDS ON/OFF
CAPZONS: SUBZONE, SOURCE
SOLUTION
SOLUTION
RESET
STOP
26
-------
Figure 3.3 Capture zones generated for a well discharge of 970 m'/day
Figure 3.4 Capture zones generated for a well discharge of 990 m3/day.
27
-------
In the remaining examples, we will introduce more advanced modeling techniques, and the
following CZAEM commands:
GIVEN: RAIN
LINESINK: GIVEN, STRING ON/OFF
CHECK: AQUIFER,GIVEN,REFERENCE,DISCHARGE,CONTROL,SUMNARY
WELL: RANGE
LINESINK: RANGE,STRING, ENDS, BVAL, DISCHARGE
WINDOW: ALL, POP, PUSH
TRACE: CURSOR ON/OFF
SET: MAXSTEP, FRONT ON/OFF, MARKER, TIME
LAYOUT: BASE, SURFACE, COORDINATE, WLL, TOL, MENU
CAPZONE: COORDINATE, BASE, SURFACE, TIMEZONE, NLINE
PAGE, COLOR, BSAVE, BREAD
CURSOR: LAYOUT: WLMOVE, LSMOVE
SWITCH: PREFIX, INPUT/OUTPUT/MESSAGES/ERROR, LOG ON/OFF, CALL,
BACK
SAVE: GRID, BOTH
READ: GRID, BOTH, DIFGRID
PSET: PRINTER, SCREEN, PALETTE, MOUSE ON/OFF
We strongly encourage you to complete the advanced tutorial lessons, but you should now be
able to apply CZAEM effectively to many small-scale practical problems as a stand-alone program.
28
-------
CZAEM TUTORIAL - PART B
EXAMPLE 4. CONTAMINANT PUMPOUT SYSTEM
A contaminant plume has been identified in a confined aquifer upgradient of a rural subdivi-
sion. To avoid contamination of private wells, the contaminant is to be pumped out of the aquifer.
Field studies have identified the plume limits and estimated aquifer properties. Three monitoring
wells have been installed to evaluate local ground-water flow conditions. A proposed pumpout
system is to place a well at coordinates (100,20) of discharge rate 220 mVday (Figure 4. 1).
Monitoring Well 2
t = 128.29 m
(-542,750)
(-500,568)
(-800,-200) +
(-300,0)
Proposed Well
* Q = 220 m3/day
T-*. • (100,20)
x
Monitoring Well 3
<*3 = 126.58 m
•
(500, -500)
Monitoring WeU 1
, = 129.84 m
• V
-------
2. Adding a discharge well or wells downgradient of the contaminant, strong enough to capture
the entire plume.
3. Determining time capture zones to estimate the pumping time required to capture the entire
plume assuming no longitudinal dispersion.
The strength of the initial uniform flow may be determined from the monitoring wells as in
Example 1. The results follow:
Qx = 0.0966 m3/(m day)
Qy = 0.0259 m3/(m day)
Qa = 0.100 m3/(rn day) (a = 15°)
To model the existing site conditions, input the aquifer parameters (Figure 4.2) and given
strength elements (i.e., uniform flow). Using consistent units of measure, enter
> 1
4>i = 129.84 m
Q
MW # 2
02 = 128.29 m
O
Well radius = 0.10 m
> i
Figure 4.2 Conceptual model of the aquifer.
aquifer
perm 2
thick 20
base 100
poro 0.25
ret
giv
uni 0.1 15
ret
To complete the model of existing conditions, a reference point where the head is known must
be entered. Here, as in Example 1, a good choice is one of the monitoring wells. We will choose
MW#1.
30
-------
ref
-750 -875 129.84
We must solve, set a window size, grid, and plot the existing conditions to view the results
(Figure 4.3).
solve
window -1000 -1000 1000 1000
grid 40
plot
d 20
[enter]
Figure 4.3 Existing conditions: uniform flow with reference head of 129.84 meters
at (-750, -875).
Obtaining results using CHECK.
At this point it is useful to test our model to make sure that it reflects observed conditions.
Modules CHECK and CURSOR provide two means of testing results. Here we will introduce
CHECK; CURSOR will be discussed later. The module CHECK allows the user to check input
data as well as model results, including point values of head and discharge. We will begin by
checking point values, Enter the module by typing
check
CZAEM responds with
\\\ Module=CHECK Level=l Routine=INPUT
(X, Y) (X, Y)
31
-------
A good test for the model is to see whether it reproduces the observed heads at the monitoring
wells. Type "head" followed by the coordinates of MW#2:
head -542 750
CZAEM responds with
X Y HEAD
-5.420000E+02 7.500000E+02 1.282863E+02
Now, check the head at MW#3:
head 500 -500
CZAEM responds with
X Y HEAD
5.000000E+02 -5.000000E+02 1.265788E+02
We can also check the discharge at any point in the aquifer. As uniform flow is the only element
contained in the current model, discharge will be the same throughout the flowfield. Check the
discharge at the origin.
discharge 0 0
CZAEM responds with
X , Y 0. OOOOOOE+OOO. OOOOOOE+00
QX , QY 9.659258E-02 2.588191E-02
The results are consistent with the field data. Commands , ,
, , , and in module CHECK allow the user to
check input data. Enter each command to check your input. Only the first four commands apply
to the current model. When you are finished, return to the MAIN menu,
The model of existing conditions is now complete. To test the proposed pumpout system
design, a well must be added near the plume, Ideally, the reference point should be far enough
away from the area of interest so that elements added to the model (in this case a well) have a
minimal effect on the head at the reference point. Here, the reference point must be moved away
from the area of interest. The problem is easily handled in this simple case. Use the above model
to check the head far from the plume. A reasonable choice here may be ( -2000,-2000).
ohe
head -2000 -2000
CZAEM computes the head at the entered coordinates and responds
X Y HEAD
-2.000000E+03 -2.000000E+03 1.335864E+02
Return to the MAIN menu.
ret
Use the results to set a new reference point at -2000, -2000.
ref
-2000 -2000 133.586
CZAEM stores only one reference point. Adding the reference point at -2000,-2000 replaces
the previous reference point. Solve, grid, and plot the revised solution (Figure 4.4).
32
-------
solve
grid 40
plot
d 20
[enter]
Figure 4.4 Existing conditions: uniform How with reference head of 133.586 meters
at (-2000, -2000).
The solution should be exactly the same as the prior solution. To verify this, enter the check
module and once again check the heads at the monitoring wells using the same command sequence
as before, If the data has been entered correctly, the results will be consistent with the field data.
Now use MAP to identify visually the plume and monitoring wells on the screen. The com-
mand is used to show the locations of the monitoring wells (Figure 4.1). Field data
provide coordinates of points on the perimeter of the plume (Figure 4.1), which are plotted with
< CURVE>,
map
plot on
point
-750 -875
-542 750
500 -500
curve
-500 568
-300 0
-583 -891
-800 -200
-500 568
33
-------
Check the locations of the input data using the layout command from the MAIN menu.
layout
The layout of the various elements of the model will appear on the screen without the head contours.
The proposed pumpout system includes a well at coordinates (100, 20) withdrawing 220
mVday. To check that the system captures the entire plume, add the well to the model from the
MAIN menu by entering
well
giv
100 20 220 0.1
ret
Solve, and grid the results.
solve
grid 40
Several methods may be used to check the adequacy of the well. The simplest method is to
use the command in the module TRACE to draw forward pathlines from the plume
boundary to the well. A second approach is to use in the module TRACE to
draw backward pathlines from the well. The approach we will use here is to enter CAPZONE from
the module TRACE. Once in module CAP ZONE use the command to generate the
capture zone envelopes for the well. Input the following sequence
trace
CAPZONE
d
[enter]
The contoured solution will be plotted on the screen (Figure 4.5).
Move the cursor to the discharge well. Use the [insert] key to reduce the cursor step size.
Create the subzones for the well
subzone
The capture zone envelope will be displayed on the screen, Figure 4.6. The entire plume is captured
by the well. The pumpout system appears to be adequate, but we will check conditions at the well
for any possible problems. Return to the MAIN module and enter the CHECK module,
ret
ret
check
head 100 20
CZAEM responds with
X Y HEAD
l.OOOOOOE+02 2.000000E+01 1.181211E+02
Note that the head at the well is below the elevation of the confining unit; flow near the well
is unconfined. CZAEM handles cases of combined confined/unconfined flow directly—the solution
is correct. However, you may wish to maintain confined conditions at the well. To achieve this,
the discharge of the well must be reduced. The plume may still be captured while maintaining
confined conditions by adding a second discharge well downgradient from the first. We will reduce
34
-------
• I
v
Figure 4.5 Contours with the well present.
the discharge of Well 1 to 110 mVday and add a second well discharging at the same rate 200
meters downgradient from the first. Return to the MAIN menu and reset Well 1;
ret
well
reset
y
giv
100 20 110 0.1
Well 2 may be added directly at this point
293.2 71.76 110 0.1
Determining capture zones for multiple wells.
We again wish to use the module CAPZONE to determine the capture zone envelopes for the
two discharge wells using the command , but this time we will use layout and not
plot the contours.
solve
tra
cap
1
[enter]
Move the cursor to the leftmost well (from now on we will refer to the leftmost discharge well as
Well 1 and the rightmost discharge well as Well 2).
sub
35
-------
Figure 4.6 Subzones drawn for the well.
The capture zone envelope for Well 1 will be recomputed and displayed. Move the cursor to Well 2.
The capture zone envelope for Well 2 will be displayed (Figure 4.7). Note that the entire plume
lies within the combined capture zone envelope for both wells. Return to the MAIN menu and
enter module CHECK to see that both wells remain in confined conditions.
Well water travel times.
Additional pertinent information may be obtained from CZAEM Next, we will generate time
capture zones for each discharge well to determine how long the wells must operate for their capture
zones to reach the plume. A time zone provides the zone of water that a well will capture if operated
for a specified period of time. For example, the water at the edge of a five-year time zone will be
captured by the well if it pumps continuously for five years. Return to module CAPZONE from
the MAIN module.
trace
cap
1
[enter]
Move the cursor to Well 1 and enter the command
time
CZAEM responds with
CALCULATING SUBZONES PHASE 1:
CREATING INITIAL PATHLINES FROM THE WELL
36
-------
Figure 4.7 Subzone curves for both wells.
20 ........
30 .
CALCULATING SUBZONES PHASE 2: DETERMINING LOCATION OF STAGNATION POINTS
10 .........
20 .........
30 .
CALCULATING SUBZONES PHASE 3: FILLING SUBZONS BUFFERS
10 .........
ENTER [TIME STEP] [MAXIMUM TIME] , OR
EDRAW LAST TIME ZONES, OR EFAULT TIME ZONES, ORXIT
MINIMUM AND MAXIMUM TIMES FOR CAPTURE ZONE: O.OOOOOE+00 4.7S038E+04
You may enter for default to generate ten equal increment time zones on the screen.
CZAEM determines the increment based on window size. Here we will enter a starting time zone
and five increments of twenty years each (7300 days)
7300 7300 36500
CZAEM computes and draws the capture zones in 20-year increments. Note that for Well 1,
more than 20 years of continuous pumping are required to reach the plume. Move the cursor to
Well 2 and repeat
time
7300 7300 36500
Twenty-year time zones will be displayed for Well 2 (Figure 4.8). We see that 60 years of continuous
pumping are required to reach the plume. The time zones computed so far are based on water
velocity. CZAEM allows the user to input a contaminant front velocity as a factor of the water
velocity. The velocity factor is capable of describing hydrodynamic dispersion (Strack, 1992) and
37
-------
sorption and must be determined by field studies. Here we will assume a factor of 1.1 has been
determined. While in module CAPZONE, set a front velocity factor.
front on 1.1
Figure 4.8 Twenty year time zones for Wells 1 and 2
Now move the cursor to Well 1 and enter the command.
time
7300 7300 36500
New time zones are computed based on the velocity of the front and plotted over the previously
computed time zones. Move the cursor to Well 2 and repeat (Figure 4.9). Note that time zones
with or without a front factor do not provide information as to how long pumps must operate to
capture all of a contaminant; only the time required for the contaminant front to reach the well is
provided.
Moving wells in graphics mode.
The pumpout system described here requires long periods of continuous pumping before ever
reaching the contaminant. To refine the design, the user may wish to move the discharge wells closer
to the plume and/or examine different combinations of wells and discharges. This may be done by
resetting the wells as was previously done, or it may be done directly on the graphics screen using
the command in module CURSOR. Exit both CAPZONE and TRACE, return to
the MAIN command line, enter CURSOR, and draw a layout as follows:
ret
ret
cursor
38
-------
Figure 4.9 Twenty-year time zones for the fronts, with a front velocity factor of 1.1.
lay
[enter]
Move the cursor to Well 1
wlmove
CZAEM responds with
PLEASE RE-POSITION CURSOR AND PRESS ENTER
Move the cursor to the location where you wish to place the well. If the cursor was not originally
close to the well, CZAEM will prompt the user to set a new tolerance.
WELL NOT FOUND; MOVE CURSOR CLOSER OR RESET TOLERANCE
Enter
TOL
CZAEM responds with
PLSASE RE-POSITION CURSOR AND PRESS ENTER
Move the cursor one step and enter
[enter]
A new tolerance is now set and CZAEM responds
RTOL= 5.000000E+01
Now move the cursor to the well and enter
39
-------
Wlmove
CZAEM responds with
PLEASE RE-POSITION CURSOR AND PRESS ENTER
Move the cursor to a new position where you wish to place the well and press enter.
[enter]
The well is moved to the new position and CZAEM responds with
DISCHARGE-SPECIFIED WELL NR 1
POSITION CHANGED FROM
0.100000E+03 0.200000E+02
To
-0.166633E+03 -0.832S61E+02
CURSOR POSITION (X,Y): -0.166633E+03 -0.832S61E+02
Solve, grid and plot to check the results. Note that allows the user to change
the well location and discharge simultaneously simply by entering the new discharge following
. This process may be repeated until an optimal design is obtained.
EXAMPLE 5. DATA MANIPULATION AND MODEL REFINEMENT
Example 5 will build on the model created in Examples 2 and 3. The model will be refined
and entered via a data file instead of via the keyboard.
Using input files.
The input file exampies.dat is included in the CZAEM directory and is listed below:
* input echo off
ret
win -1000 -1000 1000 1000
aqui
perm 5
thick 50
base 0
por 0.25
ret
giv
uni 0.5 30
ret
line
head
-1500 1500 -600 1300 32
-600 1300 -200 900 33
-200 900 200 500 34
200 500 500 200 35
500 200 500 -800 37.5
500 -800 800 -1000 38
800 -1000 1100 -1000 39
1100 -1000 1500 -1800 40
ret
ref
-2000 4000 40
well
given
0 0 1000 0.3
ret
solve
swi
40
-------
end
The asterisk (*) indicates a comment statement and CZAEM shall disregard all information to
the right of the asterisk on that line. The data file applies to Examples 2 and 3 with a well
discharging 1000 mVday. To confirm this, start CZAEM and enter module SWITCH from the
MAIN command line.
CZAEM responds with
\\\ ROUTINE SWITCH ///
[(PREFIX)]
[ [FILE NAME] [LOGICAL UNIT]
(FILENAME)
The command PREFIX sets the DOS directory where files are either read or sent. The CZAEM
directory is currently the default and is specified by the file initaem.dat. The second set of
command words in SWITCH dictates how and where to send input data and program feedback.
Further information on these features is contained in the help file in this module. When a file is
read in, the input and any CZAEM error messages will scroll quickly up the monitor. To record
this information to a file, enter
log on examples. log
This creates a transcript of all information displayed on the screen (aside from graphics) which
may be consulted after exiting or when using PAUSE from the MAIN menu. If the command LOG
ON is not followed by a file name, the information is sent to the file iog.dat by default. To read
in the data file, enter either
call example5.dat
or
ret
swi example5.dat
Both of these command sequences accomplish the same. It is important to do only one or the
other, otherwise the data will be superimposed. We must RESET from the MAIN command line
before calling in the same data file the second time. Try reading in the data both ways. Also,
remove the asterisks on the first two lines and read in the file to see the effects of the command
INPUT ECHO OFF. Note that INPUT ECHO OFF is disabled after reading each file and only
the input is not displayed (the solve response is still shown on the monitor).
Saving grid files.
Enter 50 and plot. Notice that the results are the same as in Example 3 where the
data were entered manually. After viewing, enter c SAVE>; save the current grid by typing
save
grid
CZAEM responds with
{to abort}
Enter the filename
soll.gSO
41
-------
The filename is arbitrary and the extension (.§50) reflects the number of grid points chosen.
Now we will refine the model elements. Recall that head-specified line-sinks approximate
a constant head boundary along each line segment by specifying the head at the midpoint and
determining a constant discharge rate along the segment. The results are approximate as the
head matches only at the midpoint. To refine the model we divide the long line-sink nearest the
well into several smaller head-specified line-sinks. This provides more control points and a better
approximation along the bank. Field data provides the new information. Exit CZAEM and replace
the line-sinks by editing the data file exanpies.dat with the following:
line
string on
head
-1500
-600
-200
200
400
500
500
500
500
470
460
500
530
600
800
1100
ret
1500
1300
900
500
300
-100
-200
-325
-400
-300
-600
-700
-800
-900
-1000
-1000
-600
-200
200
400
500
500
500
500
470
480
500
530
600
800
1100
1500
1300
900
500
300
-100
-300
-325
-400
-500
-600
-700
-800
-900
-1000
-1000
-1800
32
33
34
34
35
36
36.
37
37
37.
37.
37.
38.
38.
39
40
.7
.5
.0
.5
.0
.2
.3
.4
.8
.0
.2
Save the file with the new data, enter CZAEM and read in the file with the command.
switch exemple5 .dat
A command present in the data file which has not yet been explained is the
command in the module LINESINK. Line-sinks may act as sources to a well (Example 3) and
subzones will be computed for each line-sink segment. This requires much computational time
and generates data which may not be of interest. For example, each line segment will be identified
as an individual source; often a user will only be interested in the total amount of water pumped
from a river, not the amount pumped from small segments. The command is used
to link line-sink segments together which will then act as a single source in subzone computations.
Comparing grids.
Enter 50 and plot the results in the module CAP ZONE. Create subzones and note
that the well no longer draws river water at a discharge of 1000 mVday (Figure 5.1). Refining the
line-sinks has improved our model and we can now determine a safe pumping level more accurately.
The subzone boundary has changed significantly due to the refinements, but the user may wish to
know the extent to which heads have changed in the refined model.
Return to the command line of the MAIN module and enter the module READ. We will
contour the difference between the original model and the refined model by entering
read
CZAEM responds with
42
-------
Figure 5.1 Case of Example 3 with refined line-sinks.
enter
difgrid
CZAEM responds with
PLEASE ENTER FILENAME; TO ABORT
enter the filename of the grid previously saved
soll.gSO
CZAEM responds with
GRIDFILE HAS BEEN SUBTRACTED FROM CURRENT GRID
and control returns to the MAIN command line. Enter the module PLOT and CZAEM responds
with
EFAULT[NUMBER OF LEVELS]AYOUT
(MIN LEVEL [INCREMENT {>0}] [MAX LEVEL]
(MAX LEVEL [DECREMENT {<0}] [MIN LEVEL]
MIN. LEVEL= -9.516754E-01 MAX. LEVEL= 9.555435E-02
These numbers represent the minimum and maximum head differences between the two models.
Contour the difgrid by entering
d 10
and observe the graphical results (Figure 5.2). We see that the greatest difference in head occurred
at the river where the contour lines are concentrated the most (here the head is approximately 1
43
-------
Figure 5.2 Refined line-sink grid minus the original line-sink grid.
meter less in the refined model than in the original model). When using DIFGRID to examine
head differences, both the number of grid points and the window size must be the same between
models.
Obtaining results using the cursor in CAPZONE.
Several additional options exist within module CAPZONE to check results. Regrid the original
solution from the MAIN command line and enter the module CAPZONE. Position the cursor over
the well and enter
coordinate
surface
base
and CZAEM responds with
2.235174E-05 2.235174E-05
UNCONFINED: X,Y, PHREATIC SURFACE 2.235174E-05 2.235174E-05 2.924427E+01
X,Y,BASE 2.235174E-05 2.235174E-05 O.OOOOOOE+00
respectively. Now return to TRACE and enter
cursor off
This moves control from the cursor to the keyboard. Enter CAPZONE and generate a plot of
the solution (grid again if you wish to see piezometric contours instead of difference contours).
SURFACE and BASE may still be used to check data, but the commands must be followed by the
coordinates of the point to be checked. Check the phreatic surface elevation at coordinates (500,
500). Enter
44
-------
surface 500 500
CZAEM responds with
UNCONFINED: X,Y, PHREATIC SURFACE 0. OOOOOOE+00 0. OOOOOOE+00 2.924426E+01
Note that SUBZONE, TIMEZONE, and WGENERATE may also be used in CURSOR OFF mode
by following the command with coordinates of the well of interest.
Validity of Solutions.
Sometimes a solution appears to be correct when observing the graphics, but may not be
valid. A clear example of this is a well which pumps the water table below the aquifer base or
below the actual vertical extent of the well. Checking the validity of a solution is always necessary,
CHECK, CURSOR, SURFACE, BASE, and COORDINATE have already been introduced as
methods of checking a solution. Here we will introduce CONTROL in the module CHECK, Note
that CONTROL appears in check levels 1 and 2. CONTROL allows the user to check input and
computed values at control points. Entering CONTROL from check level 1 will produce a listing
of all control point coordinates, specified heads, and computed heads. Large differences between
specified and computed values indicate erroneous results. Return to the MAIN command line and
enter the module CHECK. Enter CONTROL and observe CZAEM'S response. Now, enter check
level 2 by entering LINESINK and CONTROL. Only the line-sink control points are listed. The
CONTROL command is also located within REFERENCE in the CHECK module.
EXAMPLE 6. DATA FILE AND GRAPHICS CONTROL
A city located adjacent to a large river is expanding its corporate boundaries and developing
an industrial park. The city maintains two water supply wells each operating at 100 million gallons
per year; the existing wells are inadequate to handle new demands. Three new wells are proposed,
and their locations have been determined previously. The city wishes to enforce land-use zoning
near the proposed well-field to protect its water supply from contamination. The existing and
proposed well-fields are to be modeled and time zones delineated to aid in zoning decisions.
Accessing multiple data files contiguously.
Data files have been compiled for the model using an ASCII editor and are included in the
CZAEM directory. While data files can always be created in this manner, they can also be produced
with the assistance of the Geographic Analytic Element Pre-processor (GAEP) developed by Kelson
et. al, 1993. The data files and descriptions follow:
map.dat contains township and range lines, corporate boundaries, and proposed
industrial park limits;
iine.dat contains line-sinks which model the major river and tributary near the city;
exist.dat contains aquifer parameters, rain, and existing well data; and
we 11. dat contains proposed well information.
caii.dat contains call commands to the preceding data files.
Use of the data files will be taught by example. The user is encouraged to examine and
evaluate each data file line by line and to run the example by using caii.dat and by calling each
data file individually. The model area is larger than previous examples, consisting of 12 townships.
Township boundaries are included in the map.dat file. Consistent English units (feet, days) are
used in this problem.
From the MAIN command line, enter the module SWITCH and read in the data
45
-------
call call, dat
The can.dat file includes calls to map.dat, line.dat, and exist.dat. All data will scroll past
the screen and control will return to the keyboard at the MAIN command line. All elements for
reproducing existing conditions have been read in. Solve, grid the solution, and plot the model of
existing conditions (Figure 6.1).
Figure 6.1 Model of existing conditions (plot; d 10).
Entering rainfall.
All elements in the model of the existing conditions have been discussed previously except for
. The RAIN element models a constant infiltration rate over a circular area; the user
must provide centroid coordinates, a radius over which the infiltration acts, and an infiltration
rate in units of length per time. The circle in Figure 6.1 shows the area of infiltration.
is contained in the module GIVEN. The command for the present model may be found
in data file exist.dat. Note that by itself creates a mound of water in the northwest
portion of the model.
Window manipulation and saving capture zone and time zone boundaries.
The proposed conditions may now be evaluated. Return to the module SWITCH and call the
data file containing the proposed well information.
call
well.dat
The data are read and control is returned to the keyboard at the MAIN command line. Solve and
grid the solution (Figure 6.2).
46
-------
Figure 6.2 Model of proposed conditions (plot; 780 5).
Within module CAPZONE move the cursor to the northernmost well and enter .
CZAEM responds with
CALCULATING SUBZONES PHASE 1:
CALCULATING SUBZONES PHASE 2:
CALCULATING SUBZONES PHASE 3:
CREATING INITIAL PATHLINSS FROM THE WELL
DETERMINING LOCATION OF STAGNATION POINTS
FILLING SUBZONE BUFFERS
CAPTURE ZONES CAN NOT BE CREATED:
NO STAGNATION POINTS FOUND IN THE WINDOW, CHANGE WINDOW SIZE
The scale of the current window is too large to evaluate the stagnation point caused by the well.
To produce a subzone, we must reduce the window size. First, store the current window plot with
the command. Enter
win push
The command stores the current window in a stack; the command
recalls the last window which has been stored in the stack. Now, reduce the window size with the
command. Position the cursor at the lower left corner of the township containing the
well. Enter
wn
CZAEM responds with
PLEASE REPOSITION CURSOR AND PRESS ENTER OR ANY OTHER KEY TO ABORT
Move the cursor upward and to the right. The cursor will drag a box with a lower left hand comer
at the initial position of the cursor. Move the cursor until the box encloses the area of interest
(the area in which you would expect the subzone to be created - in this case, the entire township
47
-------
containing the well) and press enter. The new window will be zoomed in on and a layout will be
displayed. Before creating the subzone with the command, enter
bsave
The command opens a file which stores all computed subzone and time zone boundaries.
CZAEM responds with
to abort
Enter the filename
well.bnd
All subzones created will be saved in weii.bnd until the user leaves module CAPZONE or enters
the command. Leaving CAPZONE closes the file; entering erases the file.
The saved file may be recalled by the command. Now, move the cursor to the well
and create the subzone with the command. When the subzone is created, return to the
large scale window by entering
win pop
The original large-scale window will appear with the subzone drawn around the northernmost
well. Now, instead of using to create a smaller window around the remaining four wells,
use the command. Enter
windov 34000 22000 87000 75000
The new window containing the four remaining wells will appear with a layout. Create subzones for
each well. This time we will return to a large-scale window by using the command.
Enter
win all
A large-scale window which includes all elements will appear with the subzones included (Figure
6.3). The shapes of the subzones appear in teardrop form and are finite, In this model, rain is the
only source of water in the area of interest.
Recall that subzone computations end at the border of the window in which they are computed.
As a result, subzone boundaries may be incomplete when viewed within a larger window.
Recall that was entered before creating any subzones, but we have not yet needed
. Computed boundaries will remain on screen until the module CAPZONE is left or
the command is used. To demonstrate the use of exit CAP ZONE and
TRACE. Reset the window size
window 0 0 130000 130000
Enter CAPZONE and plot the layout. Note that the proper layout appears, but the subzones are
no longer present. To reproduce the subzones, read the boundary file weii.bnd.
bread
CZAEM responds with
to abort
Enter the filename
well.bnd
The subzones are displayed on the screen. Now create time zones for each well on which the city
will base land-use planning.
48
-------
L ..
Figure 6.3 Well-jield subzones.
Obtaining a hardcopy of graphical output.
To obtain a hardcopy of Figure 6.1, we must route the output to a printer instead of the
screen. When CZAEM was installed on your computer, you were prompted for the type of printer
device you use. It is assumed here that you chose a postscript device and therefore will create a
postscript file instead of directly accessing a printer. This operation is done in the module PSET.
Return to the MAIN module and enter PSET.
ret
ret
pset
49
-------
CZAEM responds with the command line
\\\ ROUTINE SET PLOT MODE ///
(NUMBER) (/)
To print, type
printer
ret
plot
d 10
[enter]
[enter]
[enter]
This will create a postscript file of the plot called piot.ps. CZAEM sends all the graphics to the
file instead of the screen. To redirect graphical output to the screen, enter
pset
screen
To produce the hardcopy, exit CZAEM and print by typing
ret
stop
print piot.ps
Note that no plot appears on the screen as graphical output is redirected to the file. This poses a
difficulty in creating plots in TRACE and CAPZONE, where the cursor is used to identify wells
or starting points of streamlines.
To obtain hardcopies of streamline traces and capture zones, we first create the plots with the
screen as the graphical output device and record our input onto a file. We then direct graphical
output to the printer and retrace our steps to produce the plot using the recorded input file as a
guideline. In this way we can locate the cursor at desired locations without seeing it on the screen.
We turn the cursor off prior to creating the printer file, and manually enter the coordinates of
where to begin trace lines or capture zones.
To create the plot on the printer of the subzone boundaries for the well at (6.4e4,4.3e4) for
the window 34000220008700075000, enter the following commands:
window 34000 22000 87000 75000
grid 50
pset
printer
ret
trace
cursor off
capzone
d
[enter]
[enter]
6,4e4 4.3e4 subzone
ret
ret
stop
Entering the coordinates 6.4e4,4.3e4 in front of the subzone command has the same effect as moving
the cursor to the well at that location. The hardcopy is produced in the same manner as before.
The remaining commands in PSET are as follows. The command followed by
the number 1, 2, 3, or 4 results in different combinations of line colors in graphical output. The
50
-------
command will enable or disable the use of a mouse for cursor movement in graphics
mode. If your PC supports a mouse, CZAEM defaults the command MOUSE to ON unless
otherwise specified in the file initaem.dat. For consistency with this tutorial, the line 'mouse off
was placed in the file. To default to MOUSE ON, remove the indicated line in the initaem.dat
file. The command is explained in the ASCII file read, me in the CZAEM directory.
51
-------
REFERENCES
Kelson, V. A., H. M. Haitjema, S.R. Kraemer, 1993. GAEP: a geographic preprocessor for ground-
water flow modeling, Hydrological Science & Technology, 8(1-4): 74-83.
Strack, O.D.L. Groundwater Mechanics, Prentice Hall, Englewood Cliffs, N. Y., 1989.
Strack, O. D. L., 1992: A mathematical model for dispersion with a moving front in groundwater,
Water Resources Research, 28 (11), 2973-2980.
USEPA 1994. Program documentation for WhAEM Wellhead Analytic Element Model), Robert
S. Kerr Environmental Research Laboratory, Ada, OK, in press.
52
-------
COMMAND SUMMARY
Command
Aquifer
permeability
thickness
base
porosity
reset
help
return
Given
uniflow
rain
reset
help
return
Reference
Well
given
reset
help
return
Linesink
given
head
string
tolerance
reset
help
return
Solve
Check
aquifer
summary
return
given
summary
uniflow
rain
Description
input module for aquifer parameters
Hydraulic conductivity in [L/T]; default is 1.0
Thickness of the aquifer; default is 1.0
Elevation of the aquifer base; default is 0.0
Effective porosity; default is 0.3
Clears all the input data in module AQUIFER; resets to
default values
Extended help for the module AQUIFER
Exit to the MAIN menu
Input module for uniform flow and infiltration
Uniform far field component
infiltration or evaporation rate at the top of the aquifer
in [L/T]
Clears all the input data in module GIVEN
Extended help for the module GIVEN
Exit to the MAIN menu
Enter the reference point parameters
Input module for wells
Well with given discharge
Clear all the well input data
Extended help for the module WELL
Exit to the MAIN menu
Input module for line-sink
Line-sinks with given discharge (per unit length of the
line-sink)
Line-sinks with head specified at the midpoint
Make a series of line-sinks to be treated as one source in
CAPZONE
Tolerance used for joining the nodes of line-sinks when
STRING is ON
Clear all the line-sink input data
Extended help for the module LINESINK
Exit to the MAIN menu
Solve the current problem
Check the solution and the input data
Check module for aquifer parameters
General information on aquifer
Exit to the CHECK menu
Check module for uniform flow and infiltration parameters
General information on uniform flow and infiltration
General information on uniform flow
General information on rainfall
Page(s)
6,12,30
6
6
6
6
24
5-6
6-7
7
46
24
5-6,7-8
8,15,17-18,32-33
10,16,34-35
10,16
24,35
5-6,10
13-15,42
14
14
42
39
24
5-6,14
8,10,17
15,31,45
32
5-6,32
32
53
-------
Check
help
return
reference
control
well
return
summary
range
input
control
help
return
line sink
summary
range
string
ends
bval
discharge
control
help
return
head
discharge
control
summary
help
return
Window
Map
curve
point
plot
reset
Extended help for GIVEN commands
Exit to the CHECK menu 5-6,32
Check module for reference point parameters 32-33,45
Comparison of the condition at the reference point with
the computed value 45
Exit to the CHECK menu 5-6
Check module for well parameters 32
General information on wells
Specify the start and end well numbers to be checked
Display locations and radii of all wells
Display the control point conditions and the computed,
values for the wells 45
Extended help for WELL commands
Exit to the CHECK menu 5-6
Check module for line-sink parameters 32
General information on line-sinks 45
Specify the start and end line-sink numbers to be checked
Displays all the string information
Display end coordinates of line-sinks
Display boundary conditions of line-sinks
Display discharges of the line-sinks
Display the control point conditions and the computed
values for the line-sink 45
Extended help for LINESINK commands
Exit to the CHECK menu 5-6
Display the head value at a point 15,32,34
Display the discharge components at a point 32
Comparison of conditions at the control points with
computed values 32,45
General information about all the modules
Extended help for the module CHECK
Exit to MAIN menu 5-6,32
Set the viewing area; 8,10,46-48
WINDOW ALL sets the viewing area to include ALL
elements; 48
WINDOW PUSH saves the window setting and 47
WINDOW POP retrieves the window settings 47,48
(in the order in which they were saved via PUSH);
WINDOW without any options displays the current
viewing area
Input module for a map or diagram of the modeled area 11,33
Begin entry of curve coordinates 11,33
Begin entry of point coordinates 33
Turn display of the map ON or OFF 11
Clear all the MAP input 24
54
-------
Map
help
return
Layout
Grid
Plot
Trace
window
tolerance
cursor
switch
prefix
input
output
messages
error
log
call
back
help
return
set
maxstep
backward
front
marker
help
return
plot
base
surface
coordinate
trace
backward
wgenerate
wll
tol
command
Extended help for the module MAP
Exit to MAIN menu 5-6
Plot all the elements within the current window on the
screen 15,34
Compute head values at the nodes of a mesh; used by
PLOT to create head contours 8
Plot the contours computed by grid on the screen 9
Determine streamlines or capture zones 10,19
See extended help for this command
Tolerance used for determining which well the cursor is on 39
See extended help for this command 44
Input/output operations 40-41,42,45
Specify DOS path for the input and output files 41
Read a data file. With ECHO, copy input to a file 41
Write output to a file. With ECHO copy output to a file
Write messages to a file. With ECHO copy messages to a
file
Write errors to a file. With ECHO copy errors to a file
Create a log of all input/output operations 41
Read a data file 41,45.46
Return control to an input file from SWITCH
Extended help for the module SWITCH 41
Exit from SWITCH module 5-6
Set TRACE options
Set the maximum step size for tracing the particle
pathlines
Set pathlines to be trace in the backward direction 19
Activate computation of solute front; requires an optional
velocity factor multiplied by the average velocity to
compute the front position. 37-38
See extended help for this command
Extended help for SET commands
Exit to the TRACE menu 5-6
Plot the piezometric contours and allow user to trace
pathlines 10,20
Display base of the aquifer at the cursor location 44
Display surface of the aquifer at the cursor location 44
Display coordinates of the cursor location 44
Determine and display streamline through cursor location 10,34
Enable backward tracing of pathlines 19-20
Generate a specified number of pathlines from a well by
backward tracing 19-20,34
Set the lower left comer of the new window 47
Set the tolerance for well identification graphically 39
Display command words 14
55
-------
Trace
menu
return
layout
base
surface
coordinate
trace
backward
wgenerate
wll
tol
command
menu
return
capzone
coordinate
base
surface
window
wll
subzone
timezone
source
nline
page
help
command
ret urn
front
wgenerate
color
bsave
bread
help
return
Exit to the TRACE menu
Exit to the MAIN menu
Display layout of elements and allow user to trace
pathlines
Display base of the aquifer at the cursor location
Display surface of the aquifer at the cursor location
Display coordinates of the cursor location
Determine and display streamline through cursor location
Enable backward tracing of pathlines
Generate a specified number of pathlines from a well by
backward tracing
Set the lower left corner of the new window
Set the tolerance for well identification graphically
Display command words
Exit to the TRACE menu
Exit to the MAIN menu
Draw capture zones for a well
Display coordinates of the cursor location
Display base of the aquifer at the cursor location
Display surface of the aquifer at the cursor location
See extended help for this command
Set the lower left corner of the new window
Create subzones for the well at the cursor position
Create time zones for the well at the cursor position
List the sources contributing water to the well
Specify number of pathlines to be used to determine the
capture zones
Clear the screen and erase BSAVE file contents
Extended help for CAPZONE commands
Display the CAPZONE commands
Exit to the TRACE menu
Set the velocity factor for the solute front used in drawing
the time zones
Generate a specified number of pathlines from a well by
backward tracing
Specify colors for different line types;
COLOR1: dividing streamlines
COLOR2: time zones,
COLORS: subzone envelopes.
Specify a file into which subsequent capture zone
boundaries will be saved
Clear screen, Read BSAVEd file, and draw capture zone
boundaries
Extended help for the module TRACE
Exit to the MAIN menu
5-6
5-6,21
20
44
44
44
10-11,34
19-20
19-20,34
47
39
14
5-6
5-6,21
22,34,35,44
44
44
44
47
22,34,35-36,46-48
36-38
24,26
14
5-6
37-38
19-20,34
48
48
5-6
56
-------
Cursor
tolerance
switch
plot
prefix
input
output
messages
error
log
call
back
help
return
coordinates
head
discharge
tolerance
wlmove
Ismove
wll
command
menu
return
layout
coordinates
head
discharge
tolerance
wlmove
Ismove
wll
command
menu
return
help
return
Help
Switch
prefix
Enter CURSOR module for graphical data retrieval 31,38
Set the tolerance with which the cursor can detect an
element 39
input/output operations 40-41,42,45
Specify DOS path for the input and output files 41
Read a data file. With ECHO, copy input to a file 41
Write output to a file. With ECHO copy output to a file
Write messages to a file. With ECHO copy messages to a
file
Write errors to a file. With ECHO copy errors to a file
Create a log of all input/output operations 41
Read a data file 41,45,46
Return control to an input file from SWITCH
Extended help for the module SWITCH 41
Exit from SWITCH module 5-6
Plot the piezometric contours and activate cursor
Display the coordinates of the cursor location 44
Display the head at the cursor location
Display the discharge at the cursor location
Set the tolerance with which the cursor can detect an
element 39
Move a well and optionally change its discharge; also
identify a well by its number 38-40
See extended help for this command
Set the lower left comer of the new window 47
Display the command words in the module CURSOR 14
Exit to the CURSOR menu 5-6
Exit to the MAIN menu 5-6
Display layout of elements and activate cursor
Display the coordinates of the cursor location 44
Display the head at the cursor location
Display the discharge at the cursor location
Set the tolerance with which the cursor can detect an
element 39
Move a well and optionally change its discharge; also
identify a well by its number 38-40
See extended help for this command
Set the lower left corner of the new window 47
Display the command words in the module CURSOR 14
Exit to the CURSOR menu 5-6
Exit to the MAIN menu 5-6
Extended help for CURSOR commands
Exit to the MAIN menu 5-6
Extended help for the command words
Enter SWITCH module 40-41,42,45
Specify DOS path for the input and output files 41
57
-------
Switch
input
output
messages
error
log
call
back
help
return
Save
Read
Pause
Reset
Pset
printer
screen
driver
palette
mouse
help
return
Read a data file. With ECHO, copy input to a file 41
Write output to a file. With ECHO copy output to a file
Write messages to a file. With ECHO copy messages to a
file
Write errors to a file. With ECHO copy errors to a file
Create a log of all input/output operations 41
Read a data file 41,45,46
Return control to an input file from SWITCH
Extended help for the module SWITCH 41
Exit from SWITCH module 5-6
Save a solution or grid in binary format for future use 17,41
Reset the program and retrieve a solution or grid 18-19,42-43
Pause from CZAEM to access DOS 41
Clears the program of all the input data 24,41
Sets the graphical output 49-51
Sends graphical output to the printer or a file 50
Sends graphical output to the screen 50
see read.me file for details
Sets the color attributes of the screen (NUMBER= 1,2,3 or 4)
Turns the mouse on or off 51
Extended help for the module PSET
Exit from the PSET module 5-6
stop
Exit the program
12
58
•U.S. GOVERNMENT PRINTING OFFICE: 1994 - 550-001/00196
-------
-------
m
TJ
o
§
£
if> -n /
CO
tn
a>
O O m C
Sail
3^§&
Si S" 3 W
"' " ® Si
O5>2 »
I < E. w
*la
ro 3 o
8i ®
o
3 >
(D CO
52 ®
O 3
g|
o"
rn
TJ
O
TJ
>
O