United                               EPA/600/R-00/057
 Environmental Protection Agency             September 2000
            EPANET 2
        USERS MANUAL
                   By
              Lewis A. Rossman
      Water Supply and Water Resources Division
     National Risk Management Research Laboratory
             Cincinnati, OH 45268
NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
     OFFICE OF RESEARCH AND DEVELOPMENT
    U.S. ENVIRONMENTAL PROTECTION AGENCY
            CINCINNATI, OH 45268

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                         DISCLAIMER
    The information in this document has been funded wholly or in part by
the U.S. Environmental Protection Agency (EPA). It has been subjected to
the Agency's peer and administrative review, and has been approved for
publication as an EPA  document. Mention of trade names  or commercial
products does not constitute endorsement or recommendation  for use.

    Although a reasonable effort has been made to assure that the  results
obtained are correct, the computer programs  described in this manual are
experimental. Therefore the author and the U.S. Environmental  Protection
Agency are not responsible  and assume no  liability  whatsoever for  any
results or any use made of the results obtained from these programs, nor for
any damages or litigation that result from the use of these programs for any
purpose.

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                                   FOREWORD

The U.S. Environmental Protection Agency is charged by Congress with protecting the Nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency
strives to  formulate and implement actions leading to a compatible  balance between human
activities and the ability of natural systems to support and nurture life. To meet this mandate,
EPA's research  program is providing  data and technical support for solving environmental
problems today  and building a science knowledge base  necessary to manage  our ecological
resources  wisely, understand how  pollutants  affect our  health,  and  prevent  or  reduce
environmental risks in the future.

The National Risk Management Research Laboratory is the Agency's center for investigation of
technological and management approaches for reducing risks from threats to human health and
the environment. The  focus of the  Laboratory's  research  program is  on methods for the
prevention and control of pollution to the air, land, water, and subsurface resources; protection of
water quality in public water systems; remediation of contaminated sites and ground water; and
prevention and  control of indoor air  pollution. The goal  of this  research  effort is to  catalyze
development and  implementation  of innovative,  cost-effective  environmental technologies;
develop scientific and engineering information needed by EPA to  support regulatory and policy
decisions; and  provide technical  support  and information transfer  to ensure  effective
implementation of environmental regulations and strategies.

In order to meet regulatory requirements and customer expectations, water utilities are feeling a
growing need to understand better the movement and transformations undergone by treated water
introduced into their distribution systems. EPANET is a computerized simulation model that
helps  meet this  goal.  It predicts the  dynamic  hydraulic and water quality behavior within a
drinking  water  distribution system operating  over  an extended period of time. This manual
describes the operation of a newly revised version of the program that has incorporated many
modeling enhancements made over the past several years.

                                                              E. Timothy Oppelt, Director
                                           National Risk Management Research Laboratory
                                         MI

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              IV

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                              CONTENTS
CHAPTER 1 - INTRODUCTIO N	9
  1.1 WHATISEPANET	9
  1.2 HYDRAULIC MODELING CAPABILITIES	9
  1.3 WATER QUALITY MODELING CAPABILITIES	10
  1.4 STEPS IN USING EPANET	11
  1.5 ABOUT THIS MANUAL	11

CHAPTER 2 - QUICK START TUTORIAL	13
  2.1 INSTALLING EPANET	13
  2.2 EXAMPLE NETWORK	13
  2.3 PROJECT SETUP	15
  2.4 DRAWING THE NETWORK	16
  2.5 SETTING OBJECT PROPERTIES	18
  2.6 SAVING AND OPENING PROJECTS	20
  2.7 RUNNING A SINGLE PERIOD ANALYSIS	20
  2.8 RUNNING AN EXTENDED PERIOD ANALYSIS	21
  2.9 RUNNING A WATER QUALITY ANALYSIS	24

CHAPTER 3 - THE  NETWORK  MODEL	27
  3.1 PHYSICAL COMPONENTS	27
  3.2 NON-PHYSICAL COMPONENTS	34
  3.3 HYDRAULIC SIMULATION MODEL	40
  3.4 WATER QUALITY SIMULATION MODEL	41

CHAPTER  4- EPANET'S  WORKSPACE	47
  4.1 OVERVIEW	47
  4.2 MENU BAR	48
  4.3 TOOLBARS	51
  4.4 STATUS BAR	52
  4.5 NETWORK MAP	53
  4.6 DATA BROWSER	53
  4.7 MAP BROWSER	54
  4.8 PROPERTY EDITOR	54
  4.9 PROGRAM PREFERENCES	55

CHAPTER 5 -WORKING  WITH  PROJECT S	59
  5.1 OPENING AND SAVING PROJECT FILES	59
  5.2 PROJECT DEFAULTS	60
  5.3 CALIBRATION DATA	62
  5.4 PROJECT SUMMARY	64

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CHAPTER 6 -WORKING WITH  OBJECT S	65
  6.1  TYPES OF OBJECTS	65
  6.2  ADDING OBJECTS	65
  6.3  SELECTING OBJECTS	67
  6.4  EDITING VISUAL OBJECTS	67
  6.5  EDITINGNON-VISUAL OBJECTS	74
  6.6  COPYING AND PASTING OBJECTS	79
  6.7  SHAPING AND REVERSING LINKS	80
  6.8  DELETING AN OBJECT	81
  6.9  MOVING AN OBJECT	81
  6.10   SELECTING A GROUP OF OBJECTS	81
  6.11   EDITING A GROUP OF OBJECTS	82

CHAPTER 7 -WORKING WITH  THE  MAP	83
  7.1  SELECTING A MAP VIEW	83
  7.2  SETTING THE MAP'S DIMENSIONS	84
  7.3  UTILIZING A BACKDROP MAP	85
  7.4  ZOOMING THE MAP	86
  7.5  PANNING THE MAP	86
  7.6  FINDING AN OBJECT	87
  7.7  MAP LEGENDS	87
  7.8  OVER VIEW MAP	89
  7.9  MAP DISPLAY OPTIONS	89

CHAPTER 8 -ANALYZING A  NETWORK	93
  8.1  SETTING ANALYSIS OPTIONS	93
  8.2  RUNNING AN ANALYSIS	98
  8.3  TROUBLESHOOTING RESULTS	98

CHAPTER 9 - VIEWING RESULT S	101
  9.1  VIEWING RESULTS ON THE MAP	101
  9.2  VIEWING RESULTS WITH A GRAPH	103
  9.3  VIEWING RESULTS WITH A TABLE	112
  9.4  VIEWING SPECIAL REPORTS	115

CHAPTER 10  -PRINTING  AND  COPYING	121
  10.1   SELECTING A PRINTER	121
  10.2   SETTING THE PAGE FORMAT	121
  10.3   PRINT PREVIEW	122
  10.4   PRINTING THE CURRENT VIEW	122
  10.5   COPYING TO THE CLIPBOARD OR TO A FILE	123

CHAPTER 11 -IMPORTING AND  EXPORTIN G	125
  11.1   PROJECT SCENARIOS	125
  11.2   EXPORTING A SCENARIO	125
  11.3   IMPORTING A SCENARIO	126
  11.4   IMPORTING A PARTIAL NETWORK	126
  11.5   IMPORTING A NETWORK MAP	127
  11.6   EXPORTING THE NETWORK MAP	127
  11.7   EXPORTING TO A TEXT FILE	128
                                    VI

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CHAPTER 12 - FREQUENTLY  ASKED  QUESTIONS	131

APPENDIXA- UNITS OF  MEASUREMENT	135

APPENDIX B - ERROR MESSAGE S	137

APPENDIX C-COMMAND  LINE EPANE T	139
  C.I    GENERAL INSTRUCTIONS	139
  C.2    INPUT FILE FORMAT	139
  C.3    REPORT FILE FORMAT	178
  C.4    BINARY OUTPUT FILE FORMAT	181

APPENDIX D- ANALYSIS ALGORITHM S	187
  D.I    HYDRAULICS	187
  D.2    WATER QUALITY	193
  D.3    REFERENCES	199
                                   VII

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              VIM

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CHAPTER1  -INTRODUCTION
1.1     WhatisEPANET

           EPANET is a computer program  that performs  extended period  simulation of
           hydraulic and water quality behavior within pressurized pipe networks. A network
           consists of pipes,  nodes (pipe junctions),  pumps, valves and  storage tanks or
           reservoirs. EPANET tracks the flow of water in each pipe, the pressure at each node,
           the  height of water in each  tank,  and the concentration  of  a  chemical  species
           throughout the network during a simulation period comprised of multiple time steps.
           In addition to chemical species, water age and source tracing can also be simulated.

           EPANET is designed to be  a research tool  for improving our understanding of the
           movement and fate of drinking water constituents within distribution systems. It can
           be  used for many different kinds of applications in distribution  systems analysis.
           Sampling program  design, hydraulic model calibration, chlorine  residual analysis,
           and consumer exposure assessment are some examples. EPANET can help assess
           alternative management strategies for improving water quality throughout a system.
           These can include:

               •   altering source utilization within multiple source systems,

               •   altering pumping and tank filling/emptying schedules,

               •   use of satellite treatment, such as re-chlorination at storage tanks,

               •   targeted pipe cleaning and replacement.


           Running under Windows, EPANET provides an integrated environment for editing
           network input data, running hydraulic and water quality simulations, and viewing the
           results in a variety of formats.  These include color-coded network  maps, data tables,
           time series graphs, and contour plots.
1.2    Hydraulic Modeling Capabilities

           Full-featured and accurate hydraulic modeling is a prerequisite for doing effective
           water quality modeling. EPANET  contains a state-of-the-art hydraulic analysis
           engine that includes the following capabilities:

              •   places no limit on the size of the network that can be analyzed

              •   computes  friction  headless using  the  Hazen-Williams,  Darcy-
                  Weisbach, or Chezy-Manning formulas

              •   includes minor head losses for bends, fittings, etc.

              •   models constant or variable speed pumps

              •   computes pumping energy and cost

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              •   models various types of valves including  shutoff,  check, pressure
                  regulating, and flow control valves
              •   allows storage tanks to have any shape (i.e., diameter can vary with
                  height)
              •   considers multiple demand categories at nodes, each with its own
                  pattern of time variation
              •   models pressure-dependent flow issuing from  emitters (sprinkler
                  heads)
              •   can base system operation on both simple tank level or timer controls
                  and on complex rule-based controls.
1.3    Water Quality Modeling Capabilities
           In  addition to hydraulic modeling, EPANET provides the following water quality
           modeling capabilities:
              •   models the movement of a non-reactive tracer material through the
                  network over time
              •   models the movement  and fate of a reactive material as it grows
                  (e.g., a disinfection by-product) or decays (e.g., chlorine residual)
                  with time
              •   models the age of water throughout a network
              •   tracks the percent of flow from a given node reaching all other nodes
                  over time
              •   models reactions both in the bulk flow and at the pipe wall
              •   uses n-th order kinetics to model reactions in the bulk flow
              •   uses zero or first order kinetics to model reactions at the pipe wall
              •   accounts for mass transfer limitations when modeling  pipe  wall
                  reactions
              •   allows growth  or decay  reactions to proceed  up to  a limiting
                  concentration
              •   employs global reaction rate coefficients that can be modified on a
                  pipe-by-pipe basis
              •   allows wall  reaction  rate coefficients  to  be  correlated to  pipe
                  roughness
              •   allows for time-varying concentration or mass inputs at any location
                  in the network
              •   models storage tanks as being either complete  mix, plug flow, or
                  two-compartment reactors.
                                         10

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           By employing these features, EPANET can study such water quality phenomena as:

              •   blending water from different sources

              •   age of water throughout a system

              •   loss of chlorine residuals

              •   growth of disinfection by-products

              •   tracking contaminant propagation events.



1.4    Steps in Using EPANET

           One typically  carries out the following steps when using EPANET to model a water
           distribution system:
              1.  Draw  a network  representation of your distribution system (see
                  Section 6.1) or import a basic description of the network placed in a
                  text file (see Section 11.4).
              2.  Edit the  properties of  the objects that make  up the system (see
                  Section 6.4)

              3.  Describe how the system is operated (see Section 6.5)
              4.  Select a set of analysis options (see Section 8.1)
              5.  Run a hydraulic/water quality analysis (see Section 8.2)

              6.  View the  results of the analysis (see Chapter 9).


1.5    About This Manual

           Chapter 2  of this manual  describes how to install EPANET and offers up a quick
           tutorial on its use. Readers unfamiliar with the basics  of modeling distribution
           systems might wish to review Chapter 3 first before working through the tutorial.

           Chapter 3  provides  background  material  on  how  EPANET  models  a water
           distribution system. It discusses  the behavior of the physical  components  that
           comprise a distribution system as well as how additional modeling information, such
           as time variations and operational control, are handled.  It also provides an overview
           of how the numerical simulation of system hydraulics and water quality performance
           is carried out.

           Chapter 4 shows how the EPANET workspace is organized. It describes the functions
           of the various menu options and toolbar buttons, and how the three  main windows -
           the Network Map, the Browser,  and the Property Editor—are used.

           Chapter 5 discusses the project  files that store all of the information contained in an
           EPANET model  of a distribution system.  It shows how to create, open, and save
           these files as  well  as how to set  default project options. It also discusses how  to
           register calibration data that are used to compare simulation results against actual
           measurements.
                                         11

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Chapter 6 describes how one goes about building a network model of a distribution
system with EPANET. It shows how to create the various physical objects (pipes,
pumps,  valves, junctions, tanks, etc.) that make  up a system, how to edit  the
properties of these objects, and how to describe the way that system demands and
operation change overtime.

Chapter 7 explains how to use the network map that provides a graphical view of the
system  being  modeled. It  shows  how  to  view different design and  computed
parameters in color-coded fashion on the map, how to re-scale, zoom, and pan the
map, how to locate objects on the map, and what options are available to  customize
the appearance of the map.

Chapter 8 shows how to run a hydraulic/water quality analysis of a network model. It
describes the various options that control how the analysis is made and offers some
troubleshooting tips to  use when examining simulation results.

Chapter 9 discusses the various ways in which the results of an analysis can be
viewed. These include different views of the network map, various kinds of graphs
and tables, and several different types of special reports.

Chapter 10 explains how to print and copy the views discussed in Chapter 9.

Chapter 11  describes  how EPANET can import and export project scenarios. A
scenario is a subset of the data that characterizes the current conditions under which a
pipe network is being analyzed  (e.g., consumer demands, operating rules, water
quality reaction coefficients, etc.). It also discusses how to save a project's entire
database to a readable text file and how to export the network map to a variety of
formats.

Chapter 12 answers questions about how EPANET can be used to  model special
kinds of situations, such as modeling pneumatic tanks,  finding the maximum flow
available at a specific pressure, and modeling the growth of disinfection by-products.

The manual also contains several appendixes. Appendix A provides a table of units
of expression for all design and computed parameters. Appendix B is a list of error
message codes and their meanings that the program  can generate. Appendix C
describes  how EPANET can be run from a command  line prompt within a DOS
window, and discusses the  format of the files  that are used with this mode  of
operation. Appendix D provides details  of the procedures and formulas used by
EPANET in its hydraulic and water quality analysis algorithms.
                              12

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CHAPTER 2 -QUICK  START TUTORIAL
          This chapter provides a tutorial on how to use EPANET. If you are not familiar with
          the components  that comprise a water distribution system and  how these are
          represented in pipe network models you might want to review the first two sections of
          Chapter 3 first.
2.1     Installing EPANET

          EPANET Version  2 is designed to  run under the Windows 95/98/NT operating
          system of an IBM/Intel-compatible personal computer. It is distributed  as a single
          file, en2setup.exe,  which contains  a self-extracting setup  program.  To  install
          EPANET:

              l. Select Run from the Windows Start menu.
              2. Enter the full path and name of the en2setup.exe file or click  the
                 Browse button to locate it on your computer.

              3. Click the OK button type to begin the setup process.

          The setup program will ask you to choose a folder (directory) where the EPANET
          files will be placed. The default folder is c:\Program Files\EPANET2. After the
          files are installed your Start Menu will have a new item named EPANET 2.0. To
          launch EPANET simply select this item off of the Start Menu, then select EPANET
          2.0 from the submenu that appears. (The name of the executable file that runs
          EPANET under Windows is epanet2w.exe.)

          Should you wish to remove EPANET from your computer, you can use the following
          procedure:
              l. Select Settings from the Windows Start menu.
              2. Select Control Panel from the Settings menu.
              3. Double-click on the Add/Remove Programs item.
              4. Select EPANET 2.0 from the list of programs that appears.
              5. Click the Add/Remove button.
2.2    Example Network

          In this tutorial we will analyze the simple distribution network shown in Figure 2.1
          below. It consists of a source reservoir (e.g., a treatment plant clearwell) from which
          water is pumped into  a two-loop pipe network. There is also  a pipe leading to a
          storage tank that floats on the system. The ID labels for the various components are
          shown in the figure. The nodes in the network have the characteristics shown in
          Table 2.1. Pipe properties are listed in Table 2.2. In addition, the pump (Link 9) can
                                        13

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deliver 150 ft of head at a flow of 600  gpm, and the tank (Node 8) has a 60-ft
diameter, a 3.5-ft water level, and a maximum level of 20 feet.
                      PUMP
                                                    TANK
                     Figure 2.1 Example Pipe Network
                 Table 2.1 Example Network Node Properties
Node
1
2
3
4
5
6
7
8
Elevation (ft)
700
700
710
700
650
700
700
830
Demand (gpm)
0
0
150
150
200
150
0
0

Pipe
1
2
3
4
5
6
7
8
L?lSth_(ft)__
3000
5000
5000
5000
5000
7000
5000
7000
Diameter (inches)
14
12
8
8
8
10
6
6
C-Factor
100
100
100
100
100
100
100
100
                             14

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2.3    Project Setup
           Our first task is to create a new project in EPANET and make sure that certain
           default options are selected. To begin, launch EPANET, or if it is already running
           select File » New (from the menu bar) to create a new project. Then select Project
           » Defaults to open the dialog form shown  in Figure 2.2. We will use this dialog to
           have EPANET automatically label new objects with consecutive numbers starting
           from 1 as they are added to the network. On the ID Labels page of the dialog, clear
           all of the ID Prefix fields and set the ID Increment to 1. Then select the Hydraulics
           page of the dialog and set the choice of Flow Units to GPM  (gallons per minute).
           This implies that US Customary units will  be used  for all other quantities as well
           (length in feet, pipe  diameter in inches, pressure in psi,  etc.). Also select Hazen-
           Williams (H-W)  as the headless formula. If you  wanted to save these choices  for all
           future new projects you could check the Save box at the bottom of the form before
           accepting it by clicking the OK button.
                             Defaults
                               ID Labels I Properties 1 Hydraulics
                               Object
ID Piefix
                               Junctions
                               Reseivoirs
                               Tanks
                               Pipes
                               Pumps
                               Valves
                               Patterns
                               Cui₯cs
                               ID Inclement
1
                                 Save as defaults for all new projects

                                  OK         Cancel         Help
                                 Figure 2.2 Project Defaults Dialog
           Next we will select some map display options so that as we add objects to the map,
           we will see their ID labels and symbols displayed. Select View  » Options to bring
           up the Map Options dialog form. Select the Notation page on this form and check the
           settings shown in Figure 2.3 below. Then switch to the Symbols page and check all
           of the boxes. Click the OK button to accept these choices and close the dialog.
                                          15

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           Finally, before drawing our network we should insure that our map scale settings are
           acceptable.  Select View  » Dimensions to  bring up the Map Dimensions dialog.
           Note the default dimensions assigned for a new project. These settings will suffice
           for this example, so click the OK button.
                        (Map Options
                           Nodes

                           Links

                           Labels
                           Notation
                           Symbols

                           Flow Arrows

                           Background


                                  OK
 p*        Node ID's

 F*        Node Values

 IF*        Link ID1*

 IT*        Link Value*

 j~  U»B Trantparant Tart
Cancel
Main
                                  Figure 2.3 Map Options Dialog
2.4    Drawing the Network
           We are now ready to begin drawing our network by making use of our mouse and the
           buttons contained on the Map Toolbar shown below. (If the toolbar is not visible then
           select View » Toolbars » Map).

           First we will add the reservoir. Click the Reservoir button
                     . Then click the mouse
           on the map at the location of the reservoir (somewhere to the left of the map).
           Next we will add the junction nodes. Click the Junction button
           the map at the locations of nodes 2 through 7.
                          and then click on
           Finally add the tank by clicking the Tank button I "I and clicking the map where the
           tank  is located. At this  point the Network Map should look something like  the
           drawing in Figure 2.4.
                                         16

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        !* Network Map
                 Figure 2.4 Network Map after Adding Nodes
                   ripes. Let's begin with pipe 1 connecting node 2 to node 3. First
                       on the Toolbar. Then click the mouse on node 2 on the map
Next we will add the
click the Pipe button
and then on node 3. Note how an outline of the pipe is drawn as you move the mouse
from node 2 to 3. Repeat this procedure for pipes 2 through 7.

Pipe 8 is curved. To draw it, click the mouse first on Node 5. Then as you move the
mouse towards Node 6, click at those points where a change of direction is needed to
maintain the desired shape. Complete the process by clicking on Node 6.
Finally we will add the pump. Click the Pump button
on node 2.
                                                     click on node 1 and then
Next we will label the reservoir, pump and tank. Select the Text button
                                                                      on the
Map Toolbar and click somewhere close to the reservoir (Node 1). An edit box will
appear. Type in the word SOURCE and then hit the Enter key. Click next to the
pump and enter its label, then do the same  for the tank. Then click the Selection
           on the Toolbar to put the map into Object Selection mode rather than
button
Text Insertion mode.

At this point we have completed drawing the example network. Your Network Map
should look like the map in Figure 2.1. If the nodes are out of position you can move
them around by clicking the node to select it, and then dragging it with the left mouse
button held down to its new position. Note how pipes connected to the node are
moved along with the node. The labels can be repositioned in similar fashion. To re-
shape the curved Pipe 8:
    l.  First click on Pipe 8 to select it and then click the
                                                     H
button on the
       Map Toolbar to put the map into Vertex Selection mode.
                              17

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                   Select a vertex point on the pipe by clicking on it and then drag it to
                   a new position with the left mouse button held down.

                   If required, vertices can be added or deleted from the pipe by right-
                   clicking the mouse and selecting the appropriate  option from the
                   popup menu that appears.
               4.  When finished, click
to return to Object Selection mode.
2.5    Setting Object Properties

           As  objects are added to a project they are assigned a default set of properties.  To
           change the value of a specific property for an object one must select the object into
           the  Property Editor  (Figure 2.5). There are  several different ways to do this. If the
           Editor is already visible then you can simply click on the object or select it from the
           Data page of the Browser. If the Editor is not visible then you can make it appear by
           one of the following actions:
               •    Double-click the object on the map.

               •    Right-click on the object and select Properties from the pop-up
                   menu that appears.

               •    Select the  object from the Data  page of the Browser window and
                  then click the Browser's Edit button .

           Whenever the Property Editor has the focus you can press the Fl key to obtain fuller
           descriptions of the properties listed
Junction 2
Property j
'Junction ID
X-Coordinate ,
Y-Coordinate
Description
Tag
'Elevation |
Base Demand
Demand Pattern
Demand Categories
Emitter Coeff.
Initial Quality
Source Quality j

Value
2
528.46
7276.42

700
0
1



^^^

^

	
1
1




bJi
                                     Figure 2.5  Property Editor
                                          18

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Let us begin editing by selecting Node 2 into the Property Editor as shown above.
We would now enter the elevation and demand for this node in the appropriate fields.
You can use the Up  and Down arrows on the keyboard or the mouse to move
between fields.  We need only click on another object (node or link) to have its
properties appear next in the Property Editor. (We could also press the Page Down or
Page Up key to move to the next or previous object of the same type in the database.)
Thus we can simply move from object to object and fill in elevation and demand for
nodes, and length, diameter, and roughness (C-factor) for links.

For the reservoir you would enter its elevation (700) in the Total  Head field. For the
tank, enter 830 for its elevation, 4 for its initial level, 20 for its maximum level, and
60 for its diameter. For the pump, we need to  assign it a pump  curve (head versus
flow relationship). Enter the ID label 1 in the Pump Curve field.

Next we  will create Pump Curve 1. From the Data page of the Browser window,
                                                                 '*''•. I
select Curves from the dropdown list box and then click the Add  button -!f°J  A new
Curve 1 will be added to the database and the Curve Editor dialog form will appear
(see Figure 2.6). Enter the pump's design flow (600) and head (150) into this form.
EPANET automatically creates a complete pump curve from this single point. The
curve's equation is shown along with its shape. Click OK to close the Editor.
Curve Editor
Curve ID
I1
Curve Type

Description
I
Equation
^^^^^^^^^^^^EQ



   | PUMP
^]  | Head = 200.00-0.0001389(Flo«r2.00
                           Figure 2.6 Curve Editor
                              19

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2.6    Saving and Opening Projects

           Having completed the initial design of our network it is a good idea to save our work
           to a file at this point.
               i.  From the File menu select the Save As option.
               2.  In the  Save  As dialog that appears, select a folder  and file  name
                  under  which to save  this  project.  We suggest naming the file
                  tutorial.net. (An extension of .net will be added to the file name if
                  one is not supplied.)
               3.  Click OK to save the project to file.

           The project data is saved to the file in a special binary format. If you wanted to save
           the  network data to  file as readable text, use the  File » Export  » Network
           command instead.

           To open our project at some later time, we would select the Open command from the
           File menu.
2.7    Running a Single Period Analysis

           We now  have enough information to run a single  period (or snapshot) hydraulic
           analysis on  our  example network. To run the analysis select  Project  »  Run
           Analysis or click the Run button \-&-\ on the Standard Toolbar. (If the toolbar is not
           visible select View » Toolbars » Standard from the menu bar).

           If the run was unsuccessful then a Status Report window will appear indicating what
           the problem was. If it ran successfully you can view the computed results in a variety
           of ways. Try some of the following:

              •   Select Node Pressure from the Browser's Map page and observe how
                  pressure values at the nodes become color-coded. To view the legend
                  for the color-coding, select View  » Legends » Node (or  right-
                  click on an empty portion of the map and select Node Legend from
                  the popup menu). To change the legend intervals and colors,  right-
                  click on the legend to make the Legend Editor appear.

              •   Bring up the Property Editor (double-click on any node or link) and
                  note  how the computed  results are displayed at the end of the
                  property list.

              •   Create a tabular listing  of results by selecting Report » Table (or
                  by clicking the Table button     on the Standard Toolbar). Figure
                  2.7 displays such a table for the link results of this run. Note that
                  flows with negative signs means that the flow is  in the opposite
                  direction to the direction in which the pipe was drawn initially.
                                         20

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Hi Network Table - Links [~~ (
Link ID
Flow
GPM
Velocity
fps
Headloss
fl/KJt
Status _A_
617.42J 1 29
Pipe 2
Pipe 3
Pipe 4
Pipe 5
Pipe 6
Pipe?
Pipe 8
382.51
159.91
29.34
-90.09
292.42
55.58
1.09
1.02
0.19
0.57
1.19
0.63
-44.42 0.50
0.69
1.00
0.04
0.34
1.03
0.57
Open!
Open!
Open!
Open!
Open!
Open!
0.38 Open! T|
                             Figure 2.7 Example Table of Link Results
2.8    Running an Extended Period Analysis

           To make our network more realistic for analyzing an extended period of operation we
           will create a Time Pattern that makes demands at the nodes vary in a periodic way
           over the course of a day. For this simple example we will use a pattern time step of 6
           hours thus making  demands change at four different times of the day. (A  1-hour
           pattern time step is a more  typical number and  is the  default assigned to new
           projects.) We set the  pattern time step by  selecting Options-Times from  the Data
           Browser, clicking the Browser's Edit button to make the Property Editor appear (if its
           not already visible), and entering 6 for the value of the Pattern Time Step (as  shown
           in Figure 2.8 below). While we have the Time Options available we can also  set  the
           duration for which we want the extended period to  run. Let's use a 3-day period of
           time (enter 72 hours for the Duration property).
Tinas Options
Property
Total Duration
Hydraulic Time Step
Quality Time Step
Pattern Time Step
Pattern Stait Time


Mrs: Mm
\72
1:00
B:iS
""i 	
0:00



: .A.
_j

•v j

                                     Figure 2.8 Times Options
                                         21

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To create the pattern, select the Patterns category in the Browser and then click the
Add button  ^1 A new Pattern 1 will be created and the Pattern Editor dialog should
appear (see Figure 2.9). Enter the multiplier values 0.5,  1.3, 1.0, 1.2 for the time
periods 1 to 4 that will give our pattern a duration of 24 hours. The multipliers are
used to modify the demand from its base  level in each time period. Since we are
making a run of 72 hours, the pattern will wrap around to the start after each 24-hour
interval of time.
   Pattern Editor
    Pattern ID
  Description
Time Period
Multiplier
1
2
3
4
5
G
7
8
0.5 1.3 1.0 1.2
                                                                        ±J
      0

        0  1  2  3  4  5 6  7  8  9101112131415161718192021222324
                              Time (Time Period = 6 hrs)
      Load...
Save...
OK
Cancel
Help
                           Figure 2.9 Pattern Editor
We now need to  assign Pattern 1 to the Demand Pattern property of all of the
junctions in our network. We can utilize one of EPANET's Hydraulic Options to
avoid having to edit each junction individually. If you bring up the Hydraulic Options
in the Property Editor you will see that there is an item called Default Pattern. Setting
its value equal to 1 will make the Demand Pattern at each junction equal Pattern 1, as
long as no other pattern is assigned to the junction.
Next run the analysis (select Project » Run Analysis or click the     button on the
Standard Toolbar). For extended period analysis  you have  several more  ways in
which to view results:

    •   The scrollbar in the Browser's Time  controls is used to display the
        network map at different points in time. Try doing this with Pressure
        selected as the node parameter and Flow as the link parameter.
                               22

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•   The VCR-style buttons in the Browser can animate the map through
    time. Click the Forward button LLJ to start the animation and the Stop
    button
                 to stop it.

       Add flow direction arrows to the map (select View » Options,
       select the Flow Arrows page from  the  Map  Options dialog, and
       check  a style  of  arrow that you wish to use).  Then begin the
       animation again and note the change in flow direction through the
       pipe connected to the tank as the tank fills and empties over time.

       Create a time series plot for any node  or link. For example, to see
       how the water elevation in the tank changes with time:
       1 .   Click on the tank.
       2.  Select Report » Graph (or click the Graph button \±=-\ on the
           Standard Toolbar) which will display a Graph Selection dialog
           box.
       3.  Select the Time Series button on the dialog.
       4.  Select Head as the parameter to plot.
       5.  Click OK to accept your choice of graph.

Note the periodic behavior of the water elevation in the tank over time (Figure 2.10).
         Time Seiies Plot - Head for Node 8
                                                            Unix
                                    for       8
         838.0--
       t? 837.0
       13
       m
         835.0
         834.0
             0   5   10  15   20   25   30  35  40  45  50  55  60  65  70
                                     Time (hours)
                     Figure 2.10  Example Time Series Plot
                               23

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2.9    Running a Water Quality Analysis

           Next we show how to extend the analysis of our example network to include water
           quality. The simplest case would be tracking the growth in water age throughout the
           network over time. To  make  this analysis we only  have  to  select Age for the
           Parameter property in the Quality Options (select Options-Quality from  the Data
           page of the Browser, then click the Browser's Edit button to make the Property Editor
           appear). Run the analysis and select Age as the parameter to view on the map. Create
           a time series plot for Age in the tank. Note that unlike water level, 72 hours is not
           enough time for the tank to reach periodic behavior for water age. (The default initial
           condition is to start all nodes with  an age of 0.) Try repeating the simulation using a
           240-hour duration or assigning  an  initial age of 60  hours to the tank (enter  60 as the
           value of Initial Quality in the Property Editor for the tank).

           Finally we show how to simulate the transport and decay of chlorine through the
           network. Make the following changes to the database:
               i. Select Options-Quality to edit  from  the Data Browser.  In the
                  Property Editor's Parameter field type in the word Chlorine.
               2. Switch  to Options-Reactions in  the  Browser.  For Global  Bulk
                  Coefficient enter a value  of -1.0. This reflects  the rate  at  which
                  chlorine will  decay due to  reactions in the bulk flow over time. This
                  rate will apply to all pipes in the network. You could edit this value
                  for individual pipes if you needed to.
               3. Click on the reservoir node and set its Initial Quality to 1.0. This will
                  be the concentration of chlorine that continuously enters the network.
                  (Reset the initial quality in the Tank to 0 if you had changed it.)

           Now  run the example.  Use the Time controls on the Map Browser to  see  how
           chlorine levels change by location  and time throughout the simulation. Note how for
           this simple network, only junctions 5, 6, and 7 see depressed chlorine  levels because
           of being fed by low chlorine water from the tank. Create a reaction report for this run
           by selecting Report »  Reaction  from the main menu. The  report should  look like
           Figure 2.11. It  shows on average how much  chlorine loss  occurs in the  pipes as
           opposed to the tank. The term "bulk" refers to  reactions occurring in the bulk fluid
           while "wall" refers to reactions with material on the pipe wall. The latter reaction is
           zero because we did not specify any wall reaction coefficient in this example.
                                         24

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        Reaction Report

                                   Wail 0 %
                                                             Ed 0.4 Bulk
                                                             CT1 0.0 Wall
                                                             E3 0.1 Tanks
                                              Inflow Rate = 4
                     Figure 2.11 Example Reaction Report
We have only touched the surface of the various capabilities offered by EPANET.
Some additional features of the program that you should experiment with are:

    •  Editing a property for a group of objects that lie  within  a  user-
       defined area.

    •  Using Control statements to base pump operation on time of day or
       tank water levels.

    •  Exploring  different Map Options, such  as  making  node  size  be
       related to value.

    •  Attaching a backdrop map (such as a street map) to the network map.

    •  Creating different types of graphs, such as profile plots and  contour
       plots.

    •  Adding calibration data to a project and viewing a calibration report.

    •  Copying the map, a graph, or a report to the clipboard or to a  file.

    •  Saving and retrieving a design scenario (i.e., current nodal demands,
       pipe roughness values, etc.).
                               25

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              26

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CHAPTER  3 - THE  NETWORK  MODEL
           This chapter discusses how EPANET models the physical objects that constitute a
           distribution system as well as its operational parameters.  Details about how this
           information is entered into the program are presented in later chapters. An overview
           is also given on the computational methods that EPANET uses to simulate hydraulic
           and water quality transport behavior.
3.1    Physical Components
           EPANET models a water distribution system as a collection of links connected to
           nodes.  The links represent pipes, pumps, and control valves. The nodes represent
           junctions, tanks, and reservoirs. The figure below illustrates how these objects can be
           connected to one another to form a network.
                                                            Tank
                                                                 I
                    Figure 3.1  Physical Components in a Water Distribution System

           Junctions
           Junctions are points in the network where links join together and where water enters
           or leaves the network. The basic input data required for junctions are:
               •   elevation above some reference (usually mean sea level)
               •   water demand (rate of withdrawal from the network)
               •   initial water quality.
           The output results computed for junctions at all time periods of a simulation are:
               •   hydraulic head (internal energy per unit weight of fluid)
               •   pressure
               •   water quality.
                                         27

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Junctions can also:

    •  have their demand vary with time

    •  have multiple categories of demands assigned to them

    •  have negative demands indicating that water is entering the network

    •  be water quality sources where constituents enter the network

    •  contain emitters (or sprinklers) which make the outflow rate depend
       on the pressure.


Reservoirs

Reservoirs are nodes that represent an infinite external source or sink of water to the
network. They are used to model such things as lakes, rivers, groundwater aquifers,
and tie-ins to other systems. Reservoirs can also serve as water quality source points.

The primary input properties for a reservoir are its hydraulic head (equal to the water
surface elevation if the reservoir is not under pressure) and its initial quality for water
quality analysis.

Because a reservoir is a boundary point to  a network, its head and water quality
cannot be  affected by  what happens within the network.  Therefore  it has no
computed  output properties. However its head can be made to  vary with time by
assigning a time pattern to it (see Time Patterns below).


Tanks

Tanks are nodes with  storage capacity, where the volume of stored water can  vary
with time during a simulation. The primary input properties for tanks are:

    •  bottom  elevation (where water level is zero)

    •  diameter (or shape if non-cylindrical)

    •  initial, minimum and maximum water levels

    •  initial water quality.

The principal outputs computed overtime are:

    •  hydraulic head (water surface elevation)

    •  water quality.

Tanks are required to operate within their minimum and maximum levels. EPANET
stops outflow if a tank is at its minimum level and stops inflow if it is at its maximum
level. Tanks can also serve as water quality source points.
                               28

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Emitters

Emitters are devices associated with junctions that model the flow through a nozzle
or orifice that discharges to the atmosphere. The flow rate through the emitter varies
as a function of the pressure available at the node:
where q = flow  rate, p = pressure, C = discharge coefficient, and y =  pressure
exponent. For nozzles and sprinkler heads y equals 0.5 and the manufacturer usually
provides the value of the discharge coefficient in units of gpm/psi° 5 (stated  as the
flow through the device at a 1 psi pressure drop).

Emitters are used to model flow through sprinkler systems and irrigation networks.
They can also be used to simulate leakage in a pipe connected to the junction (if a
discharge coefficient and pressure exponent for the leaking crack or joint can be
estimated) or compute  a fire flow  at the junction (the flow available  at some
minimum residual pressure). In the latter case one would use a very high value of the
discharge coefficient (e.g., 100 times the maximum  flow  expected) and modify the
junction's elevation to include the  equivalent head of the  pressure target. EPANET
treats emitters as a property of a junction and not as a separate network component.


Pipes

Pipes are links that convey water from one point in the network to another. EPANET
assumes that all pipes are full at all times. Flow  direction is from the end at higher
hydraulic head (internal energy per weight of water) to that at lower head. The
principal hydraulic input parameters for pipes are:

    •   start and end nodes

    •   diameter

    •   length

    •   roughness coefficient (for determining headless)

    •   status (open, closed, or contains a check valve).

The status parameter allows pipes to implicitly contain  shutoff (gate) valves and
check (non-return) valves (which allow flow in only one direction).

The water quality inputs for pipes consist of:

    •   bulk reaction coefficient

    •   wall reaction coefficient.

These coefficients are explained more thoroughly in Section 3.4 below.
                               29

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Computed outputs for pipes include:

    •   flow rate

    •   velocity

    •   headless

    •   Darcy-Weisbach friction factor

    •   average reaction rate (over the pipe length)

    •   average water quality (over the pipe length).

The hydraulic head lost by water flowing in a pipe due to friction with the pipe walls
can be computed using one of three different formulas:

    •   Hazen-Williams formula

    •   Darcy-Weisbach formula

    •   Chezy-Manning formula

The Hazen-Williams formula is the most commonly used headless formula in the US.
It cannot be used  for liquids other than water  and was originally developed for
turbulent flow only. The Darcy-Weisbach formula is the most theoretically correct. It
applies over all flow regimes and to all liquids. The Chezy-Manning formula is more
commonly used for open channel flow.

Each formula uses the following equation to compute headless between the start and
end node of the pipe:

    hL = AqB

where  hL  = headless  (Length), q  = flow rate (Volume/Time),  A = resistance
coefficient, and B  = flow exponent. Table 3.1 lists expressions for the resistance
coefficient and values for the flow exponent for each of the formulas. Each formula
uses a different pipe roughness  coefficient that must be determined empirically.
Table 3.2 lists general  ranges of these coefficients for different types of new pipe
materials. Be aware that a pipe's roughness coefficient can change considerably with
age.

With the Darcy-Weisbach formula EPANET uses different methods to compute the
friction factor f depending on the flow regime:

    •   The Hagen-Poiseuille formula is used for laminar flow (Re < 2,000).

    •   The Swamee   and Jain  approximation to the Colebrook-White
       equation is used for fully turbulent flow (Re > 4,000).

    •   A   cubic  interpolation  from the  Moody  Diagram  is used  for
       transitional flow (2,000 < Re < 4,000) .

Consult Appendix D for the actual equations used.
                              30

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                Table 3.1 Pipe Headless Formulas for Full Flow
                     (for headloss in feet and flow rate in cfs)
Formula
Hazen-Williams
Darcy-Weisbach
Chezy-Manning
Notes:






Resistance Coefficient
(A)
4.727 C1-852 d-4871 L
0.0252 f(e,d,q)d-5L
4.66 n2 d'5 33 L
Flow Exponent
(B)
1.852
2
2
C = Hazen-Williams roughness coefficient
z = Darcy-Weisbach roughness coefficient (ft)
f = friction factor (dependent on e, d, and q)
n = Manning roughness coefficient
d = pipe diameter (ft)
L = pipe length (ft)
q = flow rate (cfs)
                Table 3.2  Roughness Coefficients for New Pipe
Material
Cast Iron
Concrete or
Concrete Lined
Galvanized Iron
Plastic
Steel
Vitrified Clay
Hazen-Williams C
(unitless)
130-140
120 - 140
120
140-150
140-150
110
Darcy-Weisbach e
(feet x Iff3)
0.85
1.0-10
0.5
0.005
0.15

Manning's n
(unitless)
0.012-0.015
0.012-0.017
0.015-0.017
0.011-0.015
0.015-0.017
0.013-0.015
Pipes can be set open or closed at preset times or when specific conditions exist, such
as when tank levels fall below or above certain set points, or when nodal pressures
fall below or above certain values. See the discussion of Controls in Section 3.2.
Minor Losses

Minor head losses (also called local losses) are caused by the added turbulence that
occurs at bends and fittings. The importance of including such losses depends on the
layout of the network and the degree of accuracy required. They can be accounted for
by assigning the pipe  a minor loss coefficient. The minor headloss  becomes  the
product of this coefficient and the velocity head of the pipe, i.e.,
                               31

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where  K = minor loss coefficient, v = flow velocity  (Length/Time), and  g =
acceleration of gravity (Length/Time2). Table 3.3 provides minor loss coefficients for
several types of fittings.
             Table 3.3  Minor Loss Coefficients for Selected Fittings
FITTING
Globe valve, fully open
Angle valve, fully open
Swing check valve, fully open
Gate valve, fully open
Short-radius elbow
Medium-radius elbow
Long-radius elbow
45 degree elbow
Closed return bend
Standard tee - flow through run
Standard tee - flow through branch
Square entrance
Exit
LOSS COEFFICIENT
10.0
5.0
2.5
0.2
0.9
0.8
0.6
0.4
2.2
0.6
1.8
0.5
1.0
Pumps

Pumps are links that impart energy to a fluid thereby raising its hydraulic head. The
principal input parameters for a pump are its start and end nodes and its pump curve
(the combination of heads and flows that the pump can produce). In lieu of a pump
curve, the pump could be represented as a constant energy device, one that supplies a
constant amount of energy (horsepower or kilowatts) to the fluid for all combinations
of flow and head.

The principal output  parameters are flow and head gain. Flow through a pump is
unidirectional and EPANET will not allow a pump to operate outside the range of its
pump curve.

Variable speed pumps can also be considered by specifying that their speed setting be
changed under these  same types of conditions.   By definition,  the  original pump
curve supplied to  the program has a relative speed setting of 1.  If the  pump speed
doubles, then the relative setting would be 2; if run at half speed, the relative setting
is 0.5 and so on. Changing the pump speed shifts the position and shape of the pump
curve (see the section on Pump Curves below).

As with pipes, pumps  can be  turned on and  off at preset times or when certain
conditions exist  in the network. A pump's  operation  can  also be described by
assigning it a time pattern of relative speed settings. EPANET can also  compute the
                              32

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energy consumption and cost of a pump. Each pump can be assigned an efficiency
curve and schedule of energy prices.  If these are not supplied then a set of global
energy options will be used.
Flow through a pump is unidirectional. If system conditions require more head than
the pump can produce, EPANET shuts the pump off. If more than the maximum flow
is required, EPANET extrapolates the pump curve to the required flow, even if this
produces a negative head. In both cases a warning message will be issued.

Valves
Valves are links that limit the pressure or flow at a specific point in the network.
Their principal input parameters include:
    •  start and end nodes
    •  diameter
    •  setting
    •  status.
The computed outputs for a valve are flow rate and headless.
The different types of valves included in EPANET are:
    •  Pressure  Reducing Valve (PRV)
    •  Pressure  Sustaining Valve (PSV)
    •  Pressure  Breaker Valve (PBV)
    •  Flow Control Valve (FCV)
    •  Throttle Control Valve (TCV)
    •  General Purpose Valve (GPV).
PRVs limit the pressure at a point in the pipe network. EPANET computes in which
of three different states a PRV can be in:
    •  partially  opened (i.e., active)  to  achieve its pressure setting on its
       downstream side when the upstream pressure is above the setting
    •  fully open if the upstream pressure is below the setting
    •  closed if the  pressure on the  downstream side  exceeds that on the
       upstream side (i.e., reverse flow is not allowed).
PSVs maintain a set pressure at  a specific point in the pipe network. EPANET
computes in which of three different states a PSV can be in:
    •  partially  opened (i.e., active) to maintain its  pressure setting on its
       upstream side when the downstream pressure is below this value
    •  fully open if the downstream pressure is above the setting
                              33

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              •   closed if the pressure on the downstream side exceeds that on the
                  upstream side (i.e., reverse flow is not allowed).

           PBVs force a specified pressure  loss to occur across the valve. Flow through the
           valve can be in either direction. PBVs are not true physical devices but can be used
           to model situations where a particular pressure drop is known to exist.

           FCVs limit the flow to a specified amount. The program produces a warning message
           if this flow cannot be maintained  without having to add additional head at the valve
           (i.e., the flow cannot be maintained even with the valve fully open).

           TCVs simulate a partially closed valve by adjusting the minor head loss coefficient of
           the valve.  A relationship between the degree to which a valve is closed and the
           resulting head loss coefficient is usually available from the valve manufacturer.

           GPVs are used to represent a link where the user supplies a special flow - head loss
           relationship instead of following one of the standard hydraulic formulas. They can be
           used to model turbines, well draw-down or reduced-flow backflow prevention valves.

           Shutoff (gate) valves and check (non-return) valves, which completely open or close
           pipes, are not considered as separate valve links but are instead included as a property
           of the pipe in which they are placed.

           Each type of valve has a different type of setting parameter that describes its
           operating point (pressure for PRVs, PSVs, and PBVs; flow for FCVs; loss coefficient
           for TCVs, and head loss curve for GPVs).

           Valves can  have their control  status overridden  by specifying  they  be  either
           completely open or completely closed. A valve's status and its setting can be changed
           during the simulation by using control statements.

           Because of the ways  in which valves are modeled the following rules apply when
           adding valves to a network:

              •   a PRV,  PSV or FCV cannot be directly connected to a reservoir  or
                  tank  (use a length of pipe to separate the two)

              •   PRVs cannot share the same downstream node or be linked in series

              •   two PSVs cannot share the same upstream node or be linked in series

              •   a PSV cannot be connected to the downstream node of a PRV.
3.2    Non-Physical Components

           In addition to physical components, EPANET employs three types of informational
           objects - curves, patterns, and controls - that describe the behavior and operational
           aspects of a distribution system.
                                         34

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Curves

Curves are objects that contain data pairs representing a relationship between two
quantities. Two or more objects can share the same curve. An EPANET model can
utilize the following types of curves:

    •  Pump Curve

    •  Efficiency Curve

    •  Volume Curve

    •  Head Loss Curve

Pump Curve

A Pump Curve represents the relationship between the head and flow rate that a
pump can deliver at its nominal speed setting. Head is the head gain imparted to the
water by the pump and is plotted on the vertical (Y) axis of the curve in feet (meters).
Flow rate is plotted on the horizontal (X) axis in flow units. A valid pump curve must
have decreasing head with increasing flow.

EPANET  will use a different shape of pump curve  depending on the number of
points supplied (see Figure 3.2):
          Single-Point Pump Curve
  Three-Point Pump Curve
              1000     2000
                 Flow (gpm)
                                               30011
      1000     2000
        Flow (gpm)
           Multi-Point Pump Curve
Variable-Speed Pump Curve

              1000     2000

                 Flow (gpm)

400


200
100
N = 2.0
~~---^^
N = 1.0 \.
N = 0.5 ^\ \
~ ~~^^^~^\ ^\ \
\ \
0 1000 2000 30
Flow (gpm)
                       Figure 3.2  Example Pump Curves
                               35

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Single-Point Curve - A single-point pump curve is defined by a single head-flow
combination that represents a pump's desired operating point. EPANET adds two
more points to the curve by assuming a shutoff head at zero flow equal to 133% of
the design head and a maximum flow at zero head equal to twice the design flow. It
then treats the curve as a three-point curve.

Three-Point Curve - A three-point pump curve is defined by three operating points: a
Low Flow point (flow and head at low or zero flow condition), a Design Flow point
(flow and head at desired operating point), and a Maximum Flow point (flow and
head at maximum flow). EPANET tries to fit a continuous function of the form

    h0 = A-Bqc

through the three points to define  the entire pump curve. In this function, hg = head
gain, q = flow rate, and A, B, and C are constants.

Multi-Point Curve - A multi-point pump curve  is defined by providing either a pair
of head-flow points or four or more such points. EPANET creates a complete curve
by connecting the points with straight-line segments.

For  variable  speed pumps,  the  pump  curve  shifts  as the speed changes. The
relationships between flow (Q) and head (H) at speeds Nl and N2 are


          NL            ^L
Efficiency Curve

An Efficiency Curve determines pump efficiency (Y in percent) as  a function of
pump flow rate (X in flow units). An example efficiency curve is shown in Figure
3.3.  Efficiency should  represent wire-to-water efficiency that takes into  account
mechanical losses in the pump itself as well as electrical losses in the pump's motor.
The  curve is used only  for energy calculations. If not supplied for a specific pump
then a fixed global pump efficiency will be used.
                              36

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Volume Curve
                             Pump Efficiency Curve


£
s-
n
'O


IUU
90

80

70
eo
sri 1




A- ^-m
/ ^,
/ ^
X ^
                                  1000     2000     3000
                                     Row [
                      Figure 3.3 Pump Efficiency Curve
A Volume  Curve determines how storage tank volume  (Y in cubic feet or cubic
meters) varies as a function of water level (X in feet or meters). It is used when it is
necessary to accurately represent tanks whose cross-sectional area varies with height.
The lower and upper water levels  supplied for the curve must contain the lower and
upper levels between which the tank operates. An example of a tank volume curve is
given below.
                                _
                                O
                                            Water Level
                       Figure 3.4 Tank Volume Curve
                              37

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Headloss Curve

A Headloss Curve is used to described the headless (Y in feet or meters) through a
General Purpose Valve (GPV) as a function of flow rate (X in flow units). It provides
the   capability  to  model devices  and  situations  with  unique  headloss-flow
relationships, such as reduced flow - backflow prevention valves, turbines, and well
draw-down behavior.
Time Patterns

A Time Pattern is a collection of multipliers that can be applied to a quantity to allow
it to vary over time. Nodal demands, reservoir heads, pump  schedules, and water
quality  source  inputs can all have  time  patterns associated with them. The time
interval used in all patterns is a fixed value, set with the project's Time Options (see
Section 8.1). Within this interval a quantity remains at a constant level, equal to the
product of  its  nominal value  and  the  pattern's  multiplier for that time  period.
Although  all time patterns must utilize the same time  interval, each can  have a
different number of periods. When the  simulation clock exceeds the number of
periods in a pattern, the pattern wraps around to its first period again.

As an example  of how time patterns work consider a junction node with an average
demand of 10 GPM. Assume that the time pattern interval has been set to 4 hours and
a pattern with the following multipliers has been specified for demand at this node:
Period
Multiplier
1
0.5
2
0.8
3
1.0
4
1.2
5
0.9
6
0.7
Then during the simulation the actual demand exerted at this node will be as follows:
Hours
Demand
0-4
5
4-8
8
8-12
10
12-16
12
16-20
9
20-24
7
24-28
5
Controls

Controls are statements that determine how the network is operated over time. They
specify  the status of selected links as a function of time, tank water levels,  and
pressures at select points within the network. There are two categories of controls
that can be used:

    •   Simple Controls

    •   Rule-Based Controls

Simple Controls

Simple controls change the status or setting of a link based on:

    •   the water level in a tank,

    •   the pressure at a junction,

    •   the time into the simulation,
                               38

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    •   the time of day.

They are statements expressed in one of the following three formats:

    LINK x  status  IF NODE  y  ABOVE/BELOW z
    LINK x  status  AT TIME  t
    LINK x  status  AT CLOCKTIME c AM/PM
where:

 x
 status

 y
 z
 t

 c
a link ID label,
OPEN or CLOSED, a pump speed setting, or a control valve
setting,
a node ID label,
a pressure for a junction or a water level for a tank,
a time since the start of the simulation in decimal hours or in
hours:minutes notation,
a 24-hour clock time.
Some examples of simple controls are:

 Control Statement

 LINK  12 CLOSED  IF NODE  23  ABOVE  20
 LINK  12 OPEN  IF  NODE 130 BELOW 30
 LINK  12  1.5  AT  TIME  16
 LINK  12 CLOSED AT CLOCKTIME 10 AM

 LINK  12 OPEN  AT  CLOCKTIME  8 PM
                                Meaning
                                (Close Link 12 when the
                                level in Tank 23 exceeds 20
                                ft.)
                                (Open Link 12 if the
                                pressure at Node 130 drops
                                below 30 psi)
                                (Set the relative speed of
                                pump  12 to 1.5 at  16 hours
                                into the simulation)
                                (Link 12 is repeatedly closed
                                at 10 AM and opened at 8
                                PM throughout the
                                simulation)
There is no limit on the number of simple control statements that can be used.

Note:  Level controls are  stated in terms of the  height of water above the tank
       bottom, not the elevation (total head) of the  water surface.

Note:  Using a pair of pressure controls to open and close a link  can cause the
       system to become  unstable if the pressure settings are  too close to one
       another. In this case using a pair of Rule-Based controls might provide more
       stability.
                              39

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           Rule-Based Controls

           Rule-Based Controls allow link status and settings to be based on a combination of
           conditions that might exist in the network after an initial hydraulic state of the system
           is computed. Here are several examples of Rule-Based Controls:

           Example 1:
           This set of rules shuts down a pump and opens a by-pass pipe when the level in a
           tank exceeds a certain value and does the opposite when the level is below another
           value.

              RULE 1
              IF   TANK    1 LEVEL  ABOVE  19.1
              THEN PUMP 335 STATUS  IS CLOSED
              AND  PIPE 330 STATUS  IS OPEN

              RULE 2
              IF   TANK    1 LEVEL  BELOW  17.1
              THEN PUMP 335 STATUS  IS OPEN
              AND  PIPE 330 STATUS  IS CLOSED

           Example 2:
           These  rules change the tank level at which a pump turns on depending on the time of
           day.

              RULE 3
              IF   SYSTEM CLOCKTIME >=  8  AM
              AND  SYSTEM CLOCKTIME < 6  PM
              AND  TANK 1 LEVEL  BELOW 12
              THEN PUMP 335 STATUS  IS OPEN

              RULE 4
              IF   SYSTEM CLOCKTIME >=  6  PM
              OR   SYSTEM CLOCKTIME < 8 AM
              AND  TANK 1 LEVEL  BELOW 14
              THEN PUMP 335 STATUS  IS OPEN

           A description of the formats used with  Rule-Based  controls can be found  in
           Appendix C, under the [RULES] heading (page 150).
3.3    Hydraulic Simulation Model

           EPANET's hydraulic simulation model computes junction heads and link flows for a
           fixed set of reservoir levels, tank levels, and water demands over a succession of
           points in time. From one time step to the next reservoir levels and junction demands
           are updated according to their prescribed time patterns while tank levels are updated
           using the current flow solution. The solution for heads and flows at a particular point
           in time  involves solving simultaneously the conservation of flow equation for each
           junction and the headless relationship across each link in the network. This process,
                                        40

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           known as "hydraulically balancing" the network, requires using an iterative technique
           to  solve the  nonlinear  equations  involved.  EPANET  employs  the  "Gradient
           Algorithm" for this purpose. Consult Appendix D for details.

           The hydraulic time step used for extended period simulation (EPS) can be set by the
           user.  A typical  value is  1  hour.  Shorter  time steps  than normal  will occur
           automatically whenever one of the following events occurs:

              •   the next output reporting time period occurs

              •   the next time pattern period occurs

              •   a tank becomes empty or full

              •   a simple control or rule-based control is activated.
3.4    Water Quality Simulation Model


           Basic Transport

           EPANET's water quality simulator uses a Lagrangian time-based approach to track
           the fate of discrete parcels of water as they move along pipes and mix together at
           junctions between  fixed-length time steps.  These water  quality time steps are
           typically much shorter than the hydraulic time step (e.g., minutes rather than hours)
           to accommodate the short times of travel that can occur within pipes.

           The method tracks the concentration and size of a series of non-overlapping segments
           of water that fills each link of the network. As time progresses, the size of the most
           upstream segment in a link increases as water enters the link while an equal loss in
           size of the most downstream segment occurs as water leaves the link. The size of the
           segments in between these remains unchanged.

           For each water quality time step, the contents of each segment are subjected to
           reaction, a cumulative account is kept of the total mass and flow volume  entering
           each node, and the  positions of the segments are updated. New node concentrations
           are then calculated, which  include the  contributions from any external  sources.
           Storage tank concentrations are updated depending on the type of mixing model that
           is used (see below). Finally, a new segment will be created at the end of each link
           that receives inflow from a node if the new node  quality differs by a user-specified
           tolerance from that  of the link's last segment.

           Initially each pipe in the network consists of a single segment whose quality equals
           the initial quality assigned to the upstream node. Whenever there is a flow reversal in
           a pipe, the pipe's parcels are re-ordered from front  to back.
                                         41

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Mixing in Storage Tanks

EPANET can use four different types of models to characterize mixing within
storage tanks as illustrated in Figure 3.5:

    •   Complete Mixing

    •   Two-Compartment Mixing

    •   FIFO Plug Flow

    •   LIFO Plug Flow
Different models can be used with different tanks within a network.
                if
                                               Main Zone
                                             Inlet-Outlet Zone
          if
          (A) Complete Mixing
(B) Two-Compartment Mixing
                                                  if
          (C) Plug Flow - FIFO
    (D) Plug Flow - LIFO
                      Figure 3.5 Tank Mixing Models

The Complete Mixing model (Figure 3.5(a)) assumes that all water that enters a tank
is instantaneously and completely mixed with the water already in the tank. It is the
simplest form of mixing behavior to assume, requires no extra parameters to describe
it, and seems to apply quite well to a large number of facilities that operate in fill-
and-draw fashion.

The Two-Compartment Mixing model (Figure 3.5(b))  divides the available  storage
volume in a tank into two compartments, both of which are  assumed completely
mixed. The  inlet/outlet pipes of the tank are assumed  to be located in the first
                             42

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compartment. New  water that enters the tank mixes  with the  water  in the first
compartment. If this compartment is full, then it sends its overflow to the  second
compartment where it completely mixes with the water already stored there. When
water leaves the tank, it exits from the first compartment, which  if full, receives an
equivalent amount of water from the second compartment to make up the difference.
The first compartment is capable of simulating short-circuiting between inflow and
outflow while  the second compartment can represent  dead zones. The user  must
supply a single  parameter, which is the fraction of the total tank volume devoted to
the first compartment.

The FIFO Plug  Flow model (Figure 3.5(c)) assumes that there is no mixing of water
at all  during its residence time  in a tank. Water parcels move through the tank in a
segregated fashion where the first parcel to enter is also the first to leave. Physically
speaking, this  model  is   most appropriate for  baffled tanks that  operate  with
simultaneous inflow and  outflow. There  are  no additional parameters needed to
describe this mixing model.

The LIFO Plug Flow model (Figure 3.5(d)) also assumes  that there is no  mixing
between parcels of water that enter a tank. However in  contrast to FIFO Plug Flow,
the water parcels stack up  one on top of another, where water enters and leaves the
tank on the bottom.  This type of model might apply to a tall, narrow standpipe with
an inlet/outlet pipe at the bottom  and a low momentum inflow.  It requires  no
additional parameters be provided.


Water Quality Reactions

EPANET can track the growth or  decay of a substance by reaction as it travels
through a distribution system. In order to do this it needs to know the rate at which
the substance reacts and  how  this rate might depend  on  substance concentration.
Reactions can occur both within the bulk flow and with material along the pipe wall.
This is illustrated in  Figure 3.6. In this example free chlorine  (HOC1) is shown
reacting with natural organic matter (NOM) in the bulk phase and is also transported
through a boundary layer at the  pipe wall to oxidize iron (Fe) released from pipe wall
corrosion. Bulk fluid reactions can also occur within tanks. EPANET allows a
modeler to treat these two reaction zones separately.
                                                       Bulk Fluid
                                        Kb
                                                  DBP
                                         ,  Fe+3  )    Boundary Layer
                   Figure 3.6 Reaction Zones Within a Pipe
                              43

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Bulk Reactions

EPANET models reactions occurring in the bulk flow with n-th order kinetics, where
the instantaneous  rate  of  reaction (R  in mass/volume/time)  is  assumed to  be
concentration-dependent according to

    R = KbC"

Here Kb = a bulk reaction rate coefficient, C = reactant concentration (mass/volume),
and n = a reaction order. Kb has units of concentration raised  to the (\-ri) power
divided by time. It is positive for growth reactions and negative for decay reactions.

EPANET can also consider reactions  where a limiting concentration exists on the
ultimate growth or loss of the substance. In this case the rate expression becomes

    R = Kh(CL-C}C("-l)        forn>Q,Kb>0

    R = Kb(C-CL)C("-l}        forn>Q,Kb 0, Kb > 0, n = 1       Trihalomethanes
 Zero-Order Kinetics             CL = 0,Kb<>0,n = 0     Water Age
 No Reaction                   CL = 0, Kb = 0            Fluoride Tracer

The Kb for first-order reactions can be estimated  by placing a sample of water in a
series of non-reacting glass bottles and  analyzing the contents of each bottle at
different points in time. If the reaction is first-order, then plotting the natural log
(C/Co) against time should result in a straight line, where Ct is concentration at time t
and Co is concentration  at time zero. Kb would then be estimated as the slope of this
line.

Bulk  reaction coefficients usually increase with increasing temperature. Running
multiple bottle tests at different temperatures will provide more accurate assessment
of how the rate coefficient varies with temperature

Wall Reactions

The  rate  of  water quality  reactions  occurring at or near the pipe wall  can  be
considered to be dependent on  the concentration in  the bulk  flow by using  an
expression of the form

    R = (AIV)KwCn
                               44

-------
where Kw = a wall reaction rate coefficient and (A/V) = the surface area per unit
volume  within a pipe (equal to  4  divided by the pipe diameter). The  latter term
converts the mass reacting per unit of wall area to a per unit volume basis. EPANET
limits the choice of wall  reaction order to either 0 or 1, so that the units of Kw are
either mass/area/time or length/time, respectively. As with Kb, Kw must be supplied to
the program by the modeler. First-order Kw values can range anywhere from 0 to as
much as 5 ft/day.

Kw should be adjusted to  account for  any mass transfer limitations  in moving
reactants and products between  the bulk flow  and the wall. EPANET does this
automatically, basing the adjustment on the molecular diffusivity of the substance
being modeled and on the  flow's Reynolds number. See  Appendix D  for details.
(Setting the molecular diffusivity  to zero will  cause  mass transfer effects to be
ignored.)

The wall reaction coefficient can depend on temperature and can also be correlated to
pipe  age and material. It is well known that as metal pipes age their roughness tends
to increase due to encrustation and tuburculation of corrosion  products on the pipe
walls. This increase in roughness produces a lower Hazen-Williams C-factor or a
higher Darcy-Weisbach roughness coefficient, resulting in greater frictional head loss
in flow through the pipe.

There is some evidence to  suggest that the same processes that increase a pipe's
roughness with age also tend to increase the reactivity of its wall with some chemical
species, particularly chlorine and  other disinfectants. EPANET can make  each pipe's
Kw be a function of the coefficient used to describe its roughness. A different function
applies depending on the formula used to compute headless through the pipe:

          Headloss Formula      Wall Reaction Formula
          Hazen-Williams        KW=F/C
          Darcy-Weisbach        Kw = -F /log(e/d)
          Chezy-Manning        Kw = F n

where C  = Hazen-Williams C-factor, e = Darcy-Weisbach roughness, d = pipe
diameter, n = Manning roughness coefficient, and F = wall reaction - pipe roughness
coefficient  The  coefficient F  must  be  developed  from site-specific  field
measurements and will have a different meaning depending  on which head  loss
equation is used. The advantage of using this approach is that it requires only a single
parameter, F, to allow wall reaction coefficients to vary throughout the network in a
physically meaningful way.


Water Age and Source Tracing

In addition to chemical transport, EPANET can also model the changes in the age of
water throughout a distribution system. Water age is the time  spent by  a parcel of
water in the network. New water  entering  the  network from  reservoirs or source
nodes enters with age of zero. Water age provides a simple, non-specific  measure of
the overall quality of delivered drinking water.  Internally,  EPANET treats age  as a
                               45

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reactive constituent whose growth follows zero-order kinetics with a rate constant
equal to 1 (i.e., each second the water becomes a second older).

EPANET can also perform  source tracing.  Source tracing tracks over time what
percent of water reaching any node in the network had its origin at a particular node.
The  source node  can be any node in the network,  including tanks  or reservoirs.
Internally, EPANET  treats   this  node  as  a  constant  source  of a  non-reacting
constituent that enters the network with a concentration of 100. Source tracing is a
useful  tool for analyzing distribution systems drawing water  from  two  or more
different raw water supplies.  It can show to what degree water from a given  source
blends with that from  other  sources,  and how the spatial pattern of this blending
changes overtime.
                               46

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CHAPTER  4-EPANET'S  WORKSPACE
           This chapter discusses the essential features of EPANET's workspace. It describes
           the main menu bar, the tool and status bars, and the three windows used most often -
           the Network Map,  the Browser,  and the Property Editor.  It also shows  how to set
          program preferences.
4.1     Overview

           The basic EPANET workspace is pictured below. It consists of the following user
           interface elements:  a Menu Bar, two Toolbars, a Status  Bar, the Network Map
           window, a Browser window, and a Property Editor window. A description of each of
           these elements is provided in the sections that follow.
             Menu Bar
       D
    Network Map
            Toolbars
                                       H  o
                                           Pipe 112
                                           Property    j Value
                                           "Pipe ID    J112
                                           •Start Node  12
                                           •Ind Mode   22
                                           Description
                                           Tag
                                           "Length

                                                                                 x
                                                                    Data  I Map

                                                                    Pipes
                                   10
                                   11
                                   12
                                   21
                                   22
                                   31
                                   110
                                   111
                                        X
      Auto-Length OH   6PM
100X    X,Y: 109.58,
92.93
                Status Bar
                  Property Editor
                    Browser
                                        47

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4.2    Menu Bar
          The Menu Bar located across the top of the EPANET workspace contains a collection
          of menus used to control the program. These include:
              •  File Menu
              •  Edit Menu
              •  View Menu
              •  Project Menu
              •  Report Menu
              •  Window Menu
              •  Help Menu

          File Menu

          The File Menu contains commands for opening and saving data files and for printing:

            Command      Description
            New            Creates a new EPANET project
            Open           Opens an existing project
            Save            Saves the current project
            Save As         Saves the current project under a different name
            Import          Imports network data or map from a file
            Export          Exports network data or map to a file
            Page Setup      Sets page margins, headers, and footers for printing
            Print Preview    Previews a printout of the current view
            Print            Prints the current view
            Preferences      Sets program preferences
            Exit            Exits EPANET
                                        48

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Edit Menu
The Edit Menu contains commands for editing and copying.
 Command
Description
 Copy To         Copies the currently active view (map, report, graph or table)
                  to the clipboard or to file
 Select Object     Allows selection of an object on the map
 Select Vertex     Allows selection of link vertices on the map
 Select Region     Allows selection of an outlined region on the map
 Select All        Makes the outlined region the entire viewable map area
 Group Edit       Edits a property for the group of objects that fall within the
                  outlined region of the map
View Menu
The View Menu controls how the network map is viewed.
 Command
 Description
 Dimensions
 Backdrop
 Pan
 Zoom In
 Zoom Out
 Full Extent
 Find
 Query
 Overview Map
 Legends
 Toolbars
 Options
 Dimensions the map
 Allows a backdrop map to be viewed
 Pans across the map
 Zooms in on the map
 Zooms out on the map
 Redraws the map at full extent
 Locates a specific item on the map
 Searches for items on the map that meet specific criteria
 Toggles the Overview Map on/off
 Controls the display of map legends
 Toggles the toolbars on/off
 Sets map appearance options
                              49

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Project Menu

The Project menu includes commands related to the current project being analyzed.

 Command          Description
 Summary          Provides a summary description of the project's
                    characteristics
 Defaults            Edits a project's default properties
 Calibration Data    Registers files containing calibration data with the project
 Analysis  Options    Edits analysis options
 Run Analysis       Runs a simulation


Report Menu

The Report menu has commands used to report analysis results in different formats.

 Command          Description
 Status             Reports changes in the status of links over time
 Energy             Reports the energy consumed by each pump
 Calibration         Reports differences between simulated and measured values
 Reaction           Reports average reaction rates throughout the network
 Full               Creates a full report of computed results for all nodes and
                    links in all time periods which is saved to a plain text file
 Graph             Creates time series, profile, frequency, and contour plots of
                    selected parameters
 Table              Creates a tabular display of selected node and link quantities
 Options            Controls the display style of a report, graph, or table
Window Menu

The Window Menu contains the following commands:

 Command           Description
 Arrange             Rearranges all child windows to fit within the main
                     window
 Close All            Closes all open windows (except the Map and Browser)
 Window List        Lists all open windows; selected window currently has
                     focus
                              50

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           Help Menu
           The Help Menu contains commands for getting help in using EPANET:
            Command
            Help Topics
            Units

            Tutorial
            About
              Description
              Displays the Help system's Help Topics dialog box
              Lists the units of measurement for all EPANET
              parameters
              Presents a short tutorial introducing the user to EPANET
              Lists information about the version of EPANET being
              used
           Context-sensitive Help is also available by pressing the Fl key.
4.3    Toolbars
           Toolbars  provide  shortcuts  to  commonly used  operations.  There are two  such
           toolbars:
              •   Standard Toolbar
              •   Map Toolbar
           The toolbars can  be  docked underneath the  Main Menu  bar  or  dragged  to any
           location on the EPANET workspace. When undocked, they can also be re-sized. The
           toolbars can be made visible or invisible by selecting View » Toolbars.

           Standard Toolbar
           The Standard Toolbar contains speed buttons for commonly used commands.
             D
            X
Opens a new project (File » New)
Opens an existing project (File » Open)
Saves the current project (File » Save)
Prints the currently active window (File » Print)
Copies selection to the clipboard or to a file (Edit » Copy To)
Deletes the currently selected item
Finds a specific item on the map (View » Find)
Runs a simulation (Project » Run Analysis)
Runs a visual query on the map (View » Query)
                                         51

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                  Creates a new graph view of results (Report » Graph)
                  Creates a new table view of results (Report » Table)
                  Modifies options for the currently active view (View » Options or Report
                  » Options)
           Map Toolbar
           The Map Toolbar contains buttons for working with the Network Map.
            m
            a
            H
            Cf
            H)
Selects an object on the map (Edit » Select Object)
Selects link vertex points (Edit » Select Vertex)
Selects a region on the map (Edit» Select Region)
Pans across the map (View » Pan)
Zooms in on the map (View » Zoom In)
Zooms out on the map (View » Zoom Out)
Draws map at full extent (View » Full Extent)
Adds a junction to the map
Adds a reservoir to the map
Adds a tank to the map
Adds a pipe to the map
Adds a pump to the map
Adds a valve to the map
Adds a label to the map
4.4    Status Bar
           The Status Bar appears at the bottom of the EPANET workspace and is divided into
           four sections which display the following information:
              •   Auto-Length  -  indicates whether automatic computation of pipe
                  lengths is turned on or off
              •   Flow Units - displays the current flow units that are in effect
              •   Zoom Level - displays the current zoom in level for the map (100%
                  is full scale)
              •   Run Status - a faucet icon shows:
                     no running water if no analysis results are available,
                                        52

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                      running water when valid analysis results are available,

                      a broken faucet when analysis results are  available but may be
                      invalid because the network data have been modified.

               •   XY Location - displays the map coordinates of the current position
                  of the mouse pointer.
4.5    Network Map
           The Network Map provides a planar schematic diagram of the objects comprising a
           water distribution network. The location of objects and the distances between them
           do not necessarily have to conform to their actual physical scale. Selected properties
           of these objects, such as water quality at nodes or flow velocity  in links, can be
           displayed by using different colors. The color-coding is described in  a Legend, which
           can be edited. New objects can  be directly added to the map and existing objects can
           be clicked on for editing, deleting, and repositioning. A backdrop drawing (such as a
           street or topographic map) can be placed behind the network map for reference. The
           map can be zoomed to any scale and panned from one position to another. Nodes and
           links  can  be drawn  at different sizes, flow direction arrows added, and  object
           symbols, ID labels and numerical property values displayed. The map can be printed,
           copied onto the Windows clipboard, or exported as a DXF file or Windows metafile.
4.6    Data Browser
           The Data Browser (shown below) is accessed from the Data tab on the Browser
           window.  It gives access to the various objects, by category (Junctions, Pipes, etc.)
           that are contained in the network being analyzed. The buttons at the bottom are used
           to add, delete, and edit these objects.
             ?P Browser
              Data   Map
              Junctions
              10
              11
              12
              13
              21
              23
              31
              32
Selects an object category
                                     Lists items in the selected category
                                    Add, Delete, and Edit buttons
                                         53

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4.7    Map Browser
           The Map Browser (shown below) is  accessed from the Map tab of the Browser
           Window. It selects the parameters and time period that are viewed in color-coded
           fashion on the Network Map. It also contains controls for animating the map through
           time.
             PP Browser
             Data   Map

             Nodes
             | Chlorine

             Links
             (Flo
             Time
             13:00 Mrs
— Selects a node variable for viewing
— Selects a link variable for viewing
                                 Selects a time period for viewing

                                 Animates the map display overtime

                                 Sets animation speed
           The animation control pushbuttons on the Map Browser work as follows:

           ffl  Rewind (return to initial time)
           LJJ  Animate back through time
           H  Stop the animation
           LLI  Animate forward in time
4.8    Property Editor
Pipe 21 Ml
Property
•Pipe ID
•Start Node
•End Node
Description
Tag
•Length
'Diameter
Value
21 [±
21 h-l
22

1365
5280
-|
10 I
•Roughness 100
:d
                                      The Property Editor (shown at the left) is used to edit
                                      the  properties  of network nodes,  links, labels, and
                                      analysis options.  It is  invoked when one of  these
                                      objects is selected (either on the Network Map  or in
                                      the   Data  Browser)  and  double-clicked  or the
                                      Browser's Edit button is clicked. The following points
                                      help explain how to use the Editor.
                                         54

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                  The Editor is a grid with two columns - one for the property's name
                  and the other for its value.

                  The columns can be re-sized by re-sizing the header at the top of the
                  Editor with the mouse.

                  The  Editor window can be moved and re-sized via  the  normal
                  Windows procedures.

                  An asterisk next to a  property name means that it is a required
                  property  - its value cannot be left blank.

                  Depending on the property, the value field  can be  one  of the
                  following:

                  •   a text box where you type in a value
                  •   a dropdown list box where you select from a list of choices
                  •   an ellipsis button which you click to bring up a specialized editor

                  •   a read-only label used to display computed results

                  The  property in  the  Editor  that currently  has focus will  be
                  highlighted with  a white background.

                  You can use both the mouse and the Up and Down arrow keys on the
                  keyboard to move between properties.

                  To begin editing the property with the focus, either begin typing a
                  value or hit the Enter key.

                  To have EPANET accept what you have entered, press the Enter key
                  or move to another property; to cancel, press the Esc key.

                  Clicking  the Close  button in the upper right corner of its title bar will
                  hide the Editor.
4.9    Program Preferences
           Program  preferences allow  you to customize  certain program features.  To  set
           program preferences select Preferences from the File menu. A  Preferences dialog
           form will appear containing two tabbed pages - one for General Preferences and one
           for Format Preferences.
                                         55

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General Preferences

The following preferences can be set on the General page of the Preferences dialog:
 Preference
 Bold Fonts
 Blinking Map Hiliter

 Flyover Map Labeling


 Confirm Deletions

 Automatic Backup File

 Temporary Directory
Description
Check to use bold fonts in all newly created windows
Check to make the selected node, link, or label on the
map blink on and off
Check to  display the ID label and current parameter
value in a hint-style box whenever the mouse is placed
over a node or link on the network map
Check to display  a confirmation dialog box before
deleting any object
Check to save  a  backup copy  of a newly  opened
project to disk named with a .bak extension
Name of the directory (folder) where EPANET writes
its temporary files
Note:  The Temporary Directory must be a file directory (folder) where the user has
       write privileges and must have sufficient space to store files which can easily
       grow to several tens of megabytes for larger networks and simulation runs.
       The  original  default  is   the   Windows   TEMP   directory  (usually
       c:\Windows\Temp).
                  Preferences
                    General  Formats ]

                         W Bold Fonts

                         fv7 Blinking Map Hiliter

                         p Flyover Map Labeling

                         P" Confirm Deletions

                         f~ Automatic Backup File

                         Temporary Directory
                                        _


                                         Select...
                       OK
         Cancel
Help
                               56

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Formatting Preferences

The Formats page of the Preferences dialog box controls how many decimal places
are displayed when results for computed parameters are reported. Use the dropdown
list boxes to select a specific Node or Link parameter. Use the spin edit boxes to
select the number of decimal places to use when displaying computed results for the
parameter. The number of decimal places displayed for any particular input design
parameter, such as pipe diameter, length, etc. is whatever the user enters.
                 Preferences

                         Node Variable
                         (Demand
                         Link Variable

                         Flow
        Decimals
        F^

        Decimals
                       Select number of decimal       In
                      use when
                       OIL
Cancel
Help
                              57

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(This page intentionally left blank.)
         58

-------
CHAPTER  5 - WORKING WITH  PROJECTS
           This chapter discusses how EPANET uses project files to store a piping network's
           data. It explains how to set certain default options for the project and how to register
           calibration data  (observed measurements)  with the project to use for  model
           evaluation.
5.1    Opening and Saving Project Files

           Project files contain all of the information used to model a network. They are usually
           named with a .NET extension.

           To create a new project:
               i.  Select File » New from the Menu Bar or click U=U on the Standard
                  Toolbar.

               2.  You will be prompted to save the existing project (if changes were
                  made to it) before the new project is created.
               3.  A new, unnamed project is created with all  options set to their
                  default values.

           A new project is automatically created whenever EPANET first begins.

           To open an existing project stored on disk:
               l.  Either select File » Open from the Menu Bar or click 1^1 on the
                  Standard Toolbar.
               2.  You will be prompted to save the current project (if changes were
                  made to it).
               3.  Select the file to open  from the Open  File dialog  form that will
                  appear. You can choose to open a file type saved previously as an
                  EPANET project (typically with a .NET  extension) or exported as a
                  text file (typically with a .INP extension). EPANET recognizes file
                  types by their content, not their names.
               4.  Click OK to close the dialog and open the selected file.

           To save a project under its current name:
                  Either select File » Save from the Menu Bar or click LJJg.1 on the
                  Standard Toolbar.
                                         59

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           To save a project using a different name:

               i.   Select File » Save As from the Menu Bar.

               2.   A  standard File Save dialog form will appear from which you can
                   select the folder and name that the project should be saved under.

           Note:   Projects are always saved as binary .NET files. To  save a project's data as
                   readable ASCII text, use the Export » Network command from the File
                   menu.
5.2    Project Defaults
           Each project has a set  of default values  that are used unless overridden  by the
           EPANET user. These values fall into three categories:

               •   Default ID labels (labels used to identify nodes and links when they
                  are first created)

               •   Default  node/link  properties  (e.g.,  node  elevation,  pipe length,
                  diameter, and roughness)

               •   Default hydraulic  analysis options (e.g.,  system of units, headless
                  equation, etc.)

           To set default values for a project:

               i.  Select Project » Defaults from the Menu Bar.
               2.  A  Defaults dialog form will appear with three pages, one for each
                  category listed above.

               3.  Check the box in the lower right of the dialog form if you want to
                  save your choices for use in all new future projects as well.
               4.  Click OK to accept your choice of defaults.

           The specific items for each category of defaults will be discussed next.


           Default ID Labels

           The ID Labels page of the Defaults dialog form is shown in Figure 5.1 below. It is
           used to determine how EPANET will assign default ID labels to network components
           when they are first created. For each type  of object one can enter a label prefix or
           leave the field blank if the default ID will simply be a number. Then one supplies an
           increment to be used when adding a  numerical  suffix to the default label. As an
           example, if J were used as a prefix  for Junctions along with an increment of 5, then as
           junctions are created they  receive  default labels of J5,  J10, J15 and so on. After an
           object has been created, the Property Editor can be used to modify its ID label if need
           be.
                                          60

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Defaults
ID Labels
Object
Junctions
Reseivoirs

Properties


Hydraulics |
ID Piefix






Tanks
Pipes
Pumps
Valves
Patterns












CUI₯CS
ID Inclement 1
n Save as defaults for
OK










all new projects
Cancel
Help

              Figure 5.1 ID Labels Page of Project Defaults Dialog
Default Node/Link Properties
The Properties page of the Defaults dialog form is shown in Figure 5.2. It sets default
property values for newly created nodes and links. These properties include:
    •   Elevation for nodes
    •   Diameter for tanks
    •   Maximum water level for tanks
    •   Length for pipes
    •   Auto-Length (automatic calculation of length) for pipes
    •   Diameter for pipes
    •   Roughness for pipes
When the Auto-Length property  is turned on, pipe  lengths will  automatically be
computed as pipes are added or repositioned on the  network map. A node or link
created  with these default properties can always be modified later on using the
Property Editor.
                               61

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Defaults
ID Labels
Property


Properties Hydraulics |
Default Value
Node Elevation 10 I
Tank Diameter iQ
Tank. Height 20
Pipe Length
Auio Length Off
Pipe Diameter 12
Pipe Roughness

n Save as c
OK

efaults for all m
Cancel

iw projects
Help


                       Figure 5.2 Properties Page of the Project Defaults Dialog
           Default Hydraulic Options

           The third page of the Defaults dialog form is used to assign default hydraulic analysis
           options. It  contains the same set of hydraulic options as the project's Hydraulic
           Options accessed from the Browser (see Section  8.1). They are repeated on the
           Project Defaults dialog so that they can be saved for use with future projects as well
           as with the current one. The most important Hydraulic Options to check when setting
           up a new project are Flow Units, Headless Formula, and Default Pattern. The choice
           of Flow  Units determines  whether all other network quantities are expressed in
           Customary  US units or in SI metric units. The choice of Headless Formula defines
           the type of the roughness coefficient to be supplied for each pipe in the network. The
           Default Pattern automatically becomes the time pattern used to vary  demands in an
           extended period simulation for all junctions not assigned any pattern.
5.3    Calibration Data
           EPANET allows you to compare results of a simulation against measured field data.
           This can be done via Time Series plots for selected locations in the network or by
           special Calibration Reports that consider multiple locations. Before EPANET can use
           such calibration data it has to be entered into a file and registered with the project.
                                          62

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Calibration Files

A Calibration File is a text file containing measured data for a particular quantity
taken over a particular period of time within a distribution system. The file provides
observed data that can be compared to the results of a network simulation. Separate
files should be  created for different parameters (e.g., pressure, fluoride, chlorine,
flow, etc.) and different sampling studies. Each line of the file contains the following
items:

    •  Location ID - ID label (as used in the network model) of the location
       where the measurement was made

    •  Time - Time (in hours) when the measurement was made

    •  Value - Result of the measurement

The  measurement time is with respect to time zero of the simulation to which the
Calibration File will be applied. It can be entered as either a decimal number (e.g.,
27.5) or in hours:minutes format (e.g., 27:30). For data to be used in a single period
analysis all time values can be 0. Comments can be added to the file by placing a
semicolon (;) before them. For a series of measurements made at the same location
the Location ID does not have to be repeated. An excerpt from a Calibration File is
shown below.

    ;Fluoride  Tracer Measurements
    /Location      Time     Value
Nl


N2

0
6.4
12.7
0.5
5. 6
0.5
1.2
0. 9
0.72
0.77
Registering Calibration Data

To register calibration data residing in a Calibration File:
    i.  Select Project » Calibration Data from the Menu Bar.
    2.  In the Calibration Data dialog form shown in Figure 5.3, click in the
       box next to the parameter you wish to register data for.
    3.  Either type in the name of a Calibration File for this parameter or
       click the Browse button to search for it.
    4.  Click the  Edit button if you want to open the Calibration  File in
       Windows Note Pad for editing.
    5.  Repeat steps 2-4 for any other parameters that have calibration data.
    6.  Click OK to accept your selections.
                              63

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                    jCalibration Data
Parametei
Demand
Total Head
Pknon
Quality
Flow
Velocity
Name of Calibration Fila



Nel2-FL.dat


                                                                         "
                                                                      Browse
                                                                       Edit
                                                       Cancel
Help
                                  Figure 5.3 Calibration Data Dialog
5.4    Project Summary
           To view a summary description of the current project select Project » Summary
           from the Menu Bar. The Project Summary dialog form will appear in which you can
           edit a descriptive title for the project as well as add notes that further describe the
           project. When you go to open a previously saved file, the Open File dialog box will
           display both of these items as different file names are selected. This makes them very
           useful for locating specific network analyses. The form also displays certain network
           statistics, such as the number of junctions, pipes, pumps, etc.
                                          64

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CHAPTER 6  - WORKING  WITH  OBJECTS
           EPANET uses various types of objects to model a distribution system. These objects
           can be accessed either directly  on the network map or from the Data page of the
           Browser window.  This chapter describes what these objects are and how they can be
           created, selected,  edited, deleted, and repositioned.
6.1     Types of Objects
           EPANET contains both physical objects that can appear on the network map, and
           non-physical objects that encompass design  and operational information. These
           objects can be classified as followed:
           (1) Nodes
              (a)  Junctions
              (b)  Reservoirs
              (c)  Tanks
           (2) Links
              (a)  Pipes
              (b)  Pumps
              (c)  Valves
           (3) Map Labels
           (4) Time Patterns
           (5) Curves
           (6) Controls
              (a)  Simple
              (b)  Rule-Based
6.2    Adding Objects

           Adding a Node
           To add a Node using the Map Toolbar:
              l.  Click the button for the type of node (junction
m
    reservoir
                 or
                  tank mi) to add from the Map Toolbar if it is not already depressed.
              2.  Move the mouse to the desired location on the map and click.
                                         65

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To add a Node using the Browser:
    i.   Select the type of node (junction, reservoir, or tank) from the Object
        list of the Data Browser.
    2.   Click the Add button.
    3.   Enter map coordinates with the Property Editor (optional).
Adding a Link
To add a straight or curved-line Link using the Map Toolbar:
    l.  Click the button for the type of link to add (pipe      pump     or
       valve      ) from the Map Toolbar if it is not already depressed.
    2.  On the map, click the mouse over the link's start node.
    3.  Move the mouse in the direction of the link's end node, clicking it at
       those intermediate points where it is  necessary to  change the link's
       direction.
    4.  Click the mouse a final time over the link's end node.
Pressing the right mouse button or the Escape key while drawing a link will cancel
the operation.
To add a straight line Link using the Browser:
    l.  Select the type of link to add  (pipe, pump, or valve) from the Object
       list of the Data Browser.
    2.  Click the Add button.
    3.  Enter the From  and To nodes of the link in the Property Editor.
Adding a Map Label
To add a label to the map:
    l.  Click the Text button LU on the Map Toolbar.
    2.  Click the mouse on the map where label should appear.
    3.  Enter the text for the label.
    4.  Press the Enter key.

Adding a Curve
To add a curve to the network database:
                               66

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               i.  Select Curve from the object category list of the Data Browser.
               2.  Click the Add button.

               3.  Edit the curve using the Curve Editor (see below).


           Adding a Time Pattern

           To add a time pattern to the network:
               i.  Select Patterns from the object category list of the Data Browser.
               2.  Click the Add button.
               3.  Edit the pattern using the Pattern Editor (see below).



           Using a Text File

           In addition to adding individual objects  interactively,  you can import a text file
           containing a list of node ID's with their coordinates as well as a list of link ID's and
           their connecting nodes (see Section 11.4 - Importing a Partial Network).
6.3    Selecting Objects
           To select an object on the map:

               i.  Make sure that the map is in Selection mode (the mouse cursor has
                  the shape of an arrow pointing up to the left). To switch to this mode,
                  either click the  Select Object button I	iLJ on the Map  Toolbar or
                  choose Select Object from the Edit menu.

               2.  Click the mouse over the desired object on the map.

           To select an object using the Browser:

               i.  Select the category  of object from the  dropdown list of the Data
                  Browser.

               2.  Select the desired object from the list below the category heading.
6.4    Editing Visual Objects
           The Property Editor (see Section 4.8) is used to edit the properties of objects that can
           appear on the Network Map (Junctions, Reservoirs, Tanks, Pipes, Pumps, Valves, or
           Labels). To edit one of these objects, select the object on the map or from the Data
           Browser, then click the Edit button JJJJ on the Data Browser (or simply double-click
           the object on the map). The properties associated with each of these types of objects
           are described in Tables 6.1 to 6.7.
                                          67

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        Note:   The unit system in which object properties are expressed  depends on the
                choice  of units for flow  rate. Using a flow rate  expressed in cubic feet,
                gallons or acre-feet means that US units will be used for all quantities. Using
                a flow rate expressed in liters or cubic meters means that SI metric units will
                be used. Flow units are selected from the project's Hydraulic Options which
                can be  accessed from the Project » Defaults menu. The units used for all
                properties are summarized in Appendix A.
PROPERTY
Junction ID


X-Coordinate


Y-Coordinate

Description

Tag

Elevation


Base Demand



Demand Pattern
DESCRIPTION
Demand
Categories
Emitter
Coefficient
Initial Quality

Source Quality
A unique label used to identify the junction. It can consist of a combination
of up to 15 numerals or characters. It cannot be the same as the ID for any
other node. This is a required property.
The horizontal location of the junction on the map, measured in the
map's distance units. If left blank the junction will not appear on the
network map.
The vertical location of the junction on the map, measured in the map's
distance units. If left blank the junction will not appear on the network map.
An optional text string that describes other significant information about the
junction.
An optional text string (with no spaces) used to assign the junction to a
category, such as a pressure zone.
The elevation in feet (meters) above some common reference of the
junction. This is a required property. Elevation is used only to compute
pressure at the junction. It does not affect any other computed quantity.
The average or nominal demand for water by the main category of consumer
at the junction, as measured in the current flow units. A negative value is
used to indicate an external source of flow into the junction. If left blank
then demand is assumed to be zero.
The ID label of the time pattern used to characterize time variation in
demand for the main category of consumer at the junction. The pattern
provides multipliers that are applied to the Base Demand to determine actual
demand in a given time period.  If left blank then the Default Time Pattern
assigned in the Hydraulic Options (see Section 8.1) will be used.
Number of different categories of water users defined for the junction. Click
the ellipsis button (or hit the Enter key) to bring up a special Demands
Editor which will let you assign base demands and time patterns to multiple
categories of users at the junction. Ignore if only a single demand category
will suffice.
Discharge coefficient for emitter (sprinkler or nozzle) placed at junction.
The coefficient represents the flow (in current flow units) that occurs at a
pressure drop of 1 psi (or meter).  Leave blank if no  emitter is present. See
the Emitters topic in Section 3.1 for more details.
Water quality level at the junction at the start of the simulation period. Can
be left blank if no water quality analysis is being made or if the level is zero.
Quality of any water entering the network at this location. Click the ellipsis
button (or hit the Enter key) to bring up the Source Quality Editor (see
Section 6.5 below).
                                          68

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                             Table 6.2 Reservoir Properties
PROPERTY
DESCRIPTION
Reservoir ID    A unique label used to identify the reservoir. It can consist of a combination of
                up to 15 numerals or characters. It cannot be the same as the ID for any other
                node. This is a required property.
X-Coordinate    The horizontal location of the reservoir on the map, measured in the map's
                distance units. If left blank the reservoir will not appear on the network map.
Y-Coordinate    The vertical location of the reservoir on the map, measured in the map's distance
                units. If left blank the reservoir will not appear on the network map.
Description     An optional text string that describes other significant information about the
                reservoir.
Tag            An optional text string (with no spaces) used to assign the reservoir to a
                category, such as a pressure zone
Total Head      The hydraulic head (elevation + pressure head) of water in the reservoir in feet
                (meters). This is a required property.
Head Pattern    The ID label of a time pattern used to model time variation in the reservoir's
                head. Leave blank if none applies. This property is useful if the reservoir
                represents a tie-in to another system whose pressure varies with time.
Initial Quality    Water quality level at the reservoir. Can be left blank if no water quality analysis
                is being made or if the level is zero.
Source          Quality of any water entering the network at this location. Click the ellipsis
Quality         button (or hit the Enter key) to bring up the Source Quality  Editor (see Section
                6.5 below).
                                Table 6.3  Tank Properties
PROPERTY
     DESCRIPTION
Tank ID             A unique label used to identify the tank. It can consist of a combination of
                     up to 15 numerals or characters. It cannot be the same as the ID for any
                     other node. This is a required property.
X-Coordinate         The horizontal location of the tank on the map, measured in the map's
                     scaling units. If left blank the tank will not appear on the network map.
Y-Coordinate         The vertical location of the tank on the map, measured in the map's scaling
                     units. If left blank the tank will not appear on the network map.
Description          Optional text string that describes other significant information about the
                     tank.
Tag                 Optional text string (with no spaces) used to assign the tank to a category,
                     such as a pressure zone
Elevation            Elevation above a common datum in feet (meters) of the bottom shell of
                     the tank. This is a required property.
Initial Level          Height in feet (meters) of the water surface above the bottom elevation of
                     the tank at the start of the simulation. This is a required property.
Minimum Level      Minimum height in feet (meters) of the water surface above the bottom
                     elevation that will be maintained. The tank will not be allowed to drop
                     below this level. This is a required property.
                                           69

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Maximum Level
Diameter
Minimum Volume
Volume Curve
Mixing Model
Mixing Fraction
Reaction
Coefficient
Initial Quality


Source Quality
Maximum height in feet (meters) of the water surface above the bottom
elevation that will be maintained. The tank will not be allowed to rise
above this level. This is a required property.
The diameter of the tank in feet (meters). For cylindrical tanks this is the
actual diameter. For square or rectangular tanks it can be an equivalent
diameter equal to 1.128 times the square root of the cross-sectional area.
For tanks whose geometry will be described by a curve (see below) it can
be set to any value. This is a required property.
The volume of water in the tank when it is at its minimum level, in cubic
feet (cubic meters). This is an optional property, useful mainly for
describing the bottom geometry of non-cylindrical tanks where a full
volume versus depth curve will not be supplied (see below).

The ID label of a curve used to describe the relation between tank volume
and water level. If no value is supplied then the tank is assumed to be
cylindrical.

The type of water quality  mixing that occurs within the tank. The choices
include

    •   MIXED (fully mixed),

    •   2COMP (two-compartment mixing),

    •   FIFO (first-in-first-out plug flow),

    •   LIFO (last-in-first-out plug flow).

See the Mixing Models topic in Section 3.4 for more information.

The fraction of the tank's total volume that comprises the inlet-outlet
compartment of the two-compartment (2COMP) mixing model. Can be left
blank if another type of mixing model is employed.

The bulk reaction coefficient for chemical reactions in the tank. Time units
are I/days. Use a positive value for growth reactions and a negative value
for decay. Leave blank if the Global Bulk reaction coefficient specified in
the project's Reactions Options will apply. See Water Quality Reactions in
Section 3.4 for more information.

Water quality level in the  tank at the start of the simulation. Can be left
blank if no water quality analysis is being made or if the level is zero.

Quality of any water entering the network at this location. Click the ellipsis
button (or hit the Enter key) to bring up the Source Quality Editor (see
Section 6.5 below).
                                          70

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                              ^Table 6.4  Pipe Properties
PROPERTY
DESCRIPTION
Pipe ID          A unique label used to identify the pipe. It can consist of a combination of up
                 to 15 numerals or characters. It cannot be the same as the ID for any other link.
                 This is a required property.
Start Node        The ID of the node where the pipe begins. This is a required property.
End Node        The ID of the node where the pipe ends. This is a required property.
Description       An optional text string that describes other significant information about the
                 pipe.
Tag             An optional text string (with no spaces) used to assign the pipe to a category,
                 perhaps one based on age or material
Length           The actual length of the pipe in feet (meters). This is a required property.
Diameter         The pipe diameter in inches (mm). This is a required property.
Roughness        The roughness coefficient of the pipe. It is unitless for Hazen-Williams or
                 Chezy-Manning roughness and has units of millifeet (mm) for Darcy-Weisbach
                 roughness. This is a required property.
Loss             Unitless minor loss coefficient associated with bends, fittings, etc. Assumed 0
Coefficient       if left blank.
Initial Status      Determines whether the pipe is initially open, closed, or contains a check
                 valve. If a check valve is  specified then the flow direction in the pipe will
                 always be from the Start node to the End node.
Bulk             The bulk reaction coefficient for the pipe. Time units are I/days. Use a positive
Coefficient       value for growth and a negative value for decay. Leave blank if the Global
                 Bulk reaction coefficient  from the project's Reaction Options will apply. See
                 Water Quality Reactions  in Section 3.4 for more information.
Wall             The wall reaction coefficient for the pipe. Time units are I/days. Use a positive
Coefficient       value for growth and a negative value for decay. Leave blank if the Global
                 Wall reaction coefficient  from the project's Reactions Options will apply. See
                 Water Quality Reactions  in Section 3.4 for more information.


    Note:   Pipe lengths can be automatically computed as pipes are added or repositioned on
            the network map  if the Auto-Length setting is turned on. To toggle this setting
            On/Off either:

            *   Select Project  » Defaults and edit the  Auto-Length field on the
                Properties page of the Defaults dialog form.

            *   Right-click over the  Auto-Length section of the Status Bar and then
                click on the popup menu item that appears.

            Be sure to provide  meaningful dimensions for the network map before
            using the Auto-Length feature (see  Section 7.2).
                                         71

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PROPERTY
             Table 6.5 Pump Properties
DESCRIPTION
Pump ID          A unique label used to identify the pump. It can consist of a combination of up
                  to 15 numerals or characters. It cannot be the same as the ID for any other link.
                  This is a required property.
Start Node        The ID of the node on the suction side of the pump. This is a required property
End Node         The ID of the node on the discharge side of the pump. This is a required
                  property
Description        An optional text string that describes other significant information about the
                  pump.
Tag              An optional text string (with no spaces) used to assign the pump to a category,
                  perhaps based on age, size or location
Pump Curve       The ID label of the pump curve used to describe the relationship between the
                  head delivered by the pump and the flow through the pump. Leave blank if the
                  pump will be a constant energy pump (see below).
Power            The power supplied by the pump in horsepower (kw). Assumes that the pump
                  supplies the same amount of energy no matter what the flow is. Leave blank if
                  a pump curve will be used instead. Use when pump curve information is not
                  available.
Speed            The relative speed setting of the pump (unitless). For example, a speed setting
                  of 1.2 implies that the rotational speed of the pump is 20% higher than the
                  normal setting.
Pattern            The ID label of a time pattern used to control the pump's operation. The
                  multipliers of the pattern are equivalent to speed settings. A multiplier of zero
                  implies that the pump will be shut off during the corresponding time period.
                  Leave blank if not applicable.
Initial Status       State of the pump (open or closed) at the start of the simulation period.
Efficiency         The ID label of the curve that represents the pump's wire-to-water efficiency
Curve             (in percent) as a function of flow rate. This information is used only to
                  compute energy usage. Leave blank if not applicable or if the global pump
                  efficiency supplied with the project's Energy Options (see Section 8.1) will be
                  used.
Energy Price       The average or nominal price of energy in monetary units per kw-hr. Used
                  only for computing the cost of energy usage. Leave blank if not applicable or if
                  the global value supplied with the project's Energy Options (Section 8.1) will
                  be used.
Price Pattern       The ID label of the time pattern used to describe the variation in energy price
                  throughout the day. Each multiplier in the pattern is applied to the pump's
                  Energy Price to determine a time-of-day pricing for the corresponding period.
                  Leave blank if not applicable or if the global pricing pattern specified in the
                  project's Energy Options (Section 8.1) will be used.
                                          72

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PROPERTY
             Table 6.6 Valve Properties
DESCRIPTION
ID Label


Start Node

End Node

Description

Tag

Diameter
Type

Setting
Loss
Coefficient
Fixed Status
A unique label used to identify the valve. It can consist of a combination of up
to 15 numerals or characters. It cannot be the same as the ID for any other link.
This is a required property.
The ID of the node on the nominal upstream or inflow side of the valve. (PRVs
and PSVs maintain flow in only a single direction.)  This is a required property.
The ID of the node on the nominal downstream or discharge side of the valve.
This is a required property.
An optional text string that describes other significant information about the
valve.
An optional text string (with no spaces) used to assign the valve to a category,
perhaps based on type or location.
The valve diameter in inches (mm). This is a required property.
The valve type (PRV, PSV, PBV, FCV, TCV, or GPV).  See Valves in Section
6.1for descriptions of the various types of valves. This is a required property.
A required parameter that describes the valve's operational setting.
Valve Type	Setting Parameter
                 PRV
                 PSV
                 PBV
                 FCV
                 TCV
                 GPV
                Pressure (psi or m)
                Pressure (psi or m)
                Pressure (psi or m)
                Flow (flow units)
                Loss Coefficient (unitless)
                ID of head loss curve
Unitless minor loss coefficient that applies when the valve is completely
opened. Assumed 0 if left blank.
Valve status at the start of the simulation. If set to OPEN or CLOSED then the
control setting of the valve is ignored and the valve behaves as an open or
closed link, respectively. If set to NONE, then the valve will behave as
intended. A valve's fixed status and its setting can be made to vary throughout a
simulation by the use of control statements. If a valve's status was fixed to
OPEN/CLOSED, then it can be made active again using a control that assigns a
new numerical setting to it.
                                          73

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                             _Table 6.7  Map Label Properties
    PROPERTY   DESCRIPTION
    Text
    X-Coordinate
              The label's text.
              The horizontal location of the upper left corner of the label on the map, measured
              in the map's scaling units. This is a required property.
Y-Coordinate   The vertical location of the upper left corner of the label on the map, measured in
              the map's scaling units. This is a required property.
Anchor Node   ID of node that serves as the label's anchor point (see Note 1 below). Leave blank
              if label will not be anchored.
Meter Type    Type of object being metered by the label (see Note 2 below). Choices are None,
              Node, or Link.
Meter ID      ID of the object (Node or Link) being metered.
Font          Launches a Font dialog that allows selection of the label's font, size, and style.
       Notes:
               A label's anchor node property is used to anchor the label relative to a
               given location on the map. When the map is zoomed in, the label will
               appear the same distance from its anchor node as it did under the  full
               extent view. This feature prevents labels from wandering too far away
               from the objects they were meant to describe when a map is zoomed.

               The Meter Type and ID properties determine if the  label will act as a
               meter. Meter labels display the value of the current viewing parameter
               (chosen from the Map Browser)  underneath the  label text. The Meter
               Type  and ID must refer to an existing node or link in the network.
               Otherwise, only the label text appears.
6.5    Editing Non-Visual Objects

           Curves, Time Patterns, and Controls have special editors that are used to define their
           properties. To edit one of these objects, select the object from the Data Browser and
           then click the Edit button  ^ I In addition, the Property Editor for Junctions contains
           an ellipsis button in the field for Demand Categories that brings up a special Demand
           Editor when clicked.  Similarly, the Source Quality field in the Property Editor for
           Junctions, Reservoirs, and Tanks has a button that launches a special Source Quality
           editor. Each of these specialized editors is described next.
                                          74

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Curve Editor

The Curve Editor is a dialog form as shown in Figure 6.1. To use the Curve Editor,
enter values for the following items:
 Item
Description
 Curve ID          ID label of the curve (maximum of 15 numerals or characters)
 Description       Optional description of what the curve represents
 Curve Type       Type of curve
 X-Y Data         X-Y data points for the curve

As you move between cells in the X-Y data table (or press the Enter key) the curve is
redrawn  in  the preview  window. For single-  and three-point pump  curves,  the
equation generated for the curve will be displayed in the Equation box. Click the OK
button to accept the curve  or the Cancel button to cancel your entries. You can also
click the Load button to load in curve data that was previously saved to file or click
the Save button to save the current curve's data to a file.
   Curve Editor
    Curve ID
  Description
    Curve Type
  Equation
    [PUMP
 | Head = 200.00-0.00013S9(Flowr2.00
                           Figure 6.1  Curve Editor
                               75

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Pattern Editor

The  Pattern Editor, displayed in Figure 6.2, edits the properties  of a time pattern
object. To use the Pattern Editor enter values for the following items:
 Item
 Description
 Pattern ID          ID label of the pattern (maximum of 15 numerals or
                    characters)
 Description        Optional description of what the pattern represents
 Multipliers         Multiplier value for each time period of the pattern.

As multipliers are entered, the preview chart is redrawn to provide a visual depiction
of the pattern.  If you  reach the end of the available Time Periods when entering
multipliers,  simply hit the  Enter  key to add  on another period. When finished
editing, click the OK button to accept the pattern or the Cancel button to cancel your
entries. You can also click the  Load button to load in pattern data that was previously
saved to file or click the Save button to save the current pattern's data to a file.
   Pattern Editor
    Pattern ID
  Description
  L.
    Time Period
    Multiplier
0.5
1.3
1.0
1.2
      0
        0  1  2  3  4  5 6  7  8 91011121314151617 13 19 20 21 22 23 24
                              Time (Time Period = 6 hrs)
  ~
      Load.
Save.
             OK
                  Cancel
                         Help
                           Figure 6.2  Pattern Editor
                                76

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Controls Editor

The Controls Editor, shown in Figure 6.3, is a text editor window used to edit both
simple and rule-based controls. It has a standard text-editing menu that is activated
by right-clicking anywhere in the Editor. The menu contains commands for Undo,
Cut, Copy, Paste, Delete, and Select All.
              ijl Simple Controls Editor
               LINK 9 OPEN II NODI 2 BELOW 110
                              II  NODI 2 ABOVE  140
                            Undo

                            tuj
                            Copy

                            Delete

                            Select All
                        OK
Cancel
Help
               Click Help to review formal of Controls statements
                          Figure 6.3 Controls Editor
Demand Editor
The Demand Editor is pictured in Figure 6.4. It is used to assign base demands and
time patterns when there is more than one category of water user at a junction. The
editor is invoked from the Property Editor by clicking the ellipsis button (or hitting
the Enter key) when the Demand Categories field has the focus.

The editor is a table  containing three columns. Each category of demand is entered as
a new row in the table. The columns contain the following information:


    •  Base Demand:  baseline  or average  demand  for  the  category
       (required)

    •  Time Pattern: ID label of time pattern used to allow demand to vary
       with time (optional)

    •  Category: text label used to identify the demand category (optional)
                               77

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                Demands for Junction 22
                          Figure 6.4 Demand Editor
The table initially is sized for 10 rows. If additional rows are needed select any cell in
the last row and hit the Enter key.

Note:  By convention,  the demand placed in the first row of the editor will be
       considered the main category for the junction and will appear in the Base
       Demand field of the Property Editor.


Source Quality Editor

The Source Quality Editor is a pop-up dialog used to describe the quality of source
flow entering the network at a specific node. This source might represent the main
treatment  works, a well head or satellite  treatment facility,  or  an  unwanted
contaminant intrusion. The dialog form, shown in Figure 6.5, contains the following
fields:
               Source Editor for Node 3
                 Source Quality
                 Time Pattern
                   Source Type
                     Concentration

                   C Mass Booster

                   C Flow Paced Booster

                     Setpoint Booster
Help

                       Figure 6.5 Source Quality Editor
                               78

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            Field                 Description
            Source Type           Select either:
                                    - Concentration
                                    - Mass Booster
                                    - Flow Paced Booster
                                    - Setpoint Booster
            Source Quality         Baseline or average concentration (or mass flow rate per
                                  minute) of source - leave blank to remove the source
            Quality Pattern         ID label of time pattern used to make source quality vary
                                  with time - leave blank if not applicable

           A water quality source can be designated as a concentration or booster source.

               •   A concentration source  fixes the  concentration of any  external
                  inflow entering the network, such as  flow from a reservoir or from a
                  negative demand placed at a junction.

               •   A mass booster source adds a fixed mass flow to that entering the
                  node from other points in the network.

               •   A flow paced booster source adds a fixed concentration to that
                  resulting from the mixing of all inflow to the node from other points
                  in the network.

               •   A setpoint  booster source fixes the  concentration of any  flow
                  leaving the  node (as long as  the concentration resulting from all
                  inflow to the node is below the  setpoint).

           The concentration-type source  is  best used  for nodes  that represent source water
           supplies or treatment works (e.g.,  reservoirs  or nodes assigned a negative demand).
           The booster-type source is best used to model direct injection of a tracer or additional
           disinfectant into the network or  to model a contaminant intrusion.
6.6    Copying and Pasting Objects

           The properties of an object displayed on the Network Map can be copied and pasted
           into another object from the same category. To copy the properties of an object to
           EPANET's internal clipboard:
               i.  Right-click the object on the map.
               2.  Select Copy from the pop-up menu that appears.

           To paste copied properties into an object:
               i.  Right-click the object on the map.
               2.  Select Paste from the pop-up menu that appears.
                                         79

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6.7    Shaping and Reversing Links

           Links can be drawn as polylines containing any number of straight-line segments that
           add change of direction and curvature to the link. Once a link has been drawn on the
           map, interior points that define these line segments can be added, deleted, and moved
           (see Figure 6.6). To edit the interior points of a link:
                  Select the link to edit on the Network Map and click U^-l on the Map
                  Toolbar (or select Edit » Select Vertex from the Menu Bar, or
                  right-click on the link and select Vertices from the popup menu).
               2.  The  mouse pointer will change  shape to  an arrow tip, and any
                  existing vertex points on the  link will  be displayed with small
                  handles around them.  To select a particular vertex, click the mouse
                  over it.

               3.  To add a new vertex to the link, right-click the mouse and select Add
                  Vertex from the popup menu (or simply press the Insert key on the
                  keyboard).
               4.  To delete the currently selected vertex, right-click the mouse and
                  select Delete  Vertex  from the popup menu (or simply  press the
                  Delete key on the keyboard).
               5.  To move a vertex to  another location, drag it with the left mouse
                  button held down to its new position.
               6.  While in Vertex Selection mode you can begin editing the vertices
                  for another link by clicking on the link. To  leave Vertex Selection
                  mode,  right-click on  the map  and select Quit Editing from the
                  popup menu, or select any other button on the Map Toolbar.
                         !" Network Map

                                          Add Vertex
                                          Delete Vertex

                                          Quil Editing
                                    Figure 6.6  Reshaping a Link
                                         80

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           A link can also have its direction reversed (i.e., its end nodes switched) by right-
           clicking on it and selecting Reverse from the pop-up menu that appears. This is
           useful for re-orienting pumps and valves that originally were added in the wrong
           direction.
6.8    Deleting an Object
           To delete an object:
               i.  Select the object on the map or from the Data Browser.
               2.  Either:
                      click
on the Standard Toolbar,
                  •   click the same button on the Data Browser,

                  •   press the Delete key on the keyboard.
            Note:  You can require that all deletions be confirmed before they take effect. See
                  the  General  Preferences page  of the Program Preferences dialog  box
                  described in Section 4.9.
6.9    Moving an Object
           To move a node or label to another location on the map:
               i.  Select the node or label.
               2.  With the left mouse button held down over the object, drag it to its
                  new location.
               3.  Release the left button.

           Alternatively, new X and Y coordinates for the object can be typed in manually in the
           Property  Editor. Whenever a node  is moved all links connected to it are moved as
           well.
6.10   Selecting a Group of Objects

           To select a group of objects that lie within an irregular region of the network map:

               i.  Select Edit» Select Region or click 1=1 on the Map Toolbar.
               2.  Draw a polygon fence line around the region  of interest on the map
                  by clicking the left mouse button at each successive vertex of the
                  polygon.
               3.  Close the polygon by clicking the  right button or by pressing the
                  Enter key; Cancel the selection by pressing the Escape key.
                                          81

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           To select all objects currently in view on the map select Edit » Select All. (Objects
           outside the current viewing extent of the map are not selected.)
           Once a group of objects has been selected, you can edit a common property (see the
           following section) or delete the selected objects from the network.  To do the latter,
           click
                 X
or press the Delete key.
6.11   Editing a Group of Objects
           To edit a property for a group of objects:
               i.  Select the region of the map that will contain the group of objects to
                  be edited using the method described in previous section.
               2.  Select Edit » Group Edit from the Menu Bar.
               3.  Define what to edit in the Group Edit dialog form that appears.
           The Group Edit dialog form, shown in Figure 6.6, is used to modify a property for a
           selected group of objects. To use the dialog form:
               i.  Select a category of object (Junctions or Pipes) to edit.
               2.  Check the  "with" box if you want to add a filter that will limit the
                  objects selected for editing. Select a property, relation and value that
                  define the filter. An example might be "with Diameter below 12".
               3.  Select the type of change to make - Replace, Multiply, or Add To.
               4.  Select the property to change.
               5.  Enter the value that  should replace, multiply, or be added to  the
                  existing value.
               6.  Click OK to  execute the group edit.
                Group Edit
For all
|7 with
(Replace **


1 Pipes T 1 within the outlined area

|Tag j*j (Equal To J^J JCasl_lion
j | 'Roughness J with J90
DK | Canc.| |






                                    Figure 6.7 Group Edit Dialog
                                          82

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CHAPTER 7 -  WORKING  WITH  THE  MAP
           EPANET displays a map of the pipe network being modeled. This chapter describes
           how you can manipulate this map to enhance your visualization of the system being
           modeled.
7.1     Selecting a Map View
           One uses the Map Page of the Browser (Section 4.7) to select a node and link
           parameter to view on the map. Parameters are viewed on the map by using colors, as
           specified in the Map Legends (see below), to display different ranges of values.
           Node parameters available for viewing include:
              •   Elevation
              •   Base Demand (nominal or average demand)
              •   Initial Quality (water quality at time zero)
              •   * Actual Demand (total demand at current time)
              •   *Hydraulic Head (elevation plus pressure head)
              •   *Pressure
              •   *Water Quality
           Link parameters available for viewing include:
              •   Length
              •   Diameter
              •   Roughness Coefficient
              •   Bulk Reaction Coefficient
              •   Wall Reaction Coefficient
              •   *Flow Rate
              •   *Velocity
              •   *Headloss (per 1000 feet (or meters) of pipe)
              •   * Friction Factor (as used in the Darcy-Weisbach headless formula)
              •   * Reaction Rate (average over length of pipe)
              •   * Water Quality (average over length of pipe)
           The items marked with asterisks are computed quantities whose values will only be
           available if a successful analysis has been run on the network (see Chapter 8 -
           Analyzing a Network).
                                         83

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7.2    Setting the Map's Dimensions

           The physical dimensions of the map must be defined so that map coordinates can be
           properly scaled to the computer's video display. To set the map's dimensions:
              i.  Select View » Dimensions.
              2.  Enter new dimension information into the  Map Dimensions dialog
                  that appears (see Figure 7.1) or click the Auto-Size button to have
                  EPANET compute dimensions based on the  coordinates  of objects
                  currently included in the network.
              3.  Click the OK button to re-size the map.
                   Map Dimensions
                     Lower Left
                      X-coordinate:

                      Y-coordinate:
             Upper Right
              X-coordinate: 173.00

              Y-coordinate: |94.
                                                 C Degrees    (•  None
                                 Figure 7.1 Map Dimensions Dialog
           The information provided in the Map Dimensions dialog consists of the following:
            Item
Description
            Lower Left Coordinates    The X and Y coordinates of the lower left point on the
                                     map.
            Upper Right Coordinates   The X and Y coordinates of the upper right point on
                                     the map.
            Map Units                Units used to measure distances on the map. Choices
                                     are Feet, Meters, Degrees, and None (i.e., arbitrary
                                     units).

           Note:  If you  are  going to use a backdrop map with  automatic  pipe length
                  calculation,  then  it  is  recommended that  you  set the map dimensions
                  immediately after creating a new project. Map distance units can be different
                  from pipe length units. The latter (feet or meters) depend on whether flow
                  rates are expressed  in  US  or metric units. EPANET will automatically
                  convert units if necessary.
                                         84

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7.3    Utilizing a Backdrop Map

           EPANET can display a backdrop map behind the pipe network map. The backdrop
           map might be a street map, utility map, topographic map, site development plan, or
           any other picture or drawing that might be useful. For example, using a street map
           would simplify the process of adding pipes to the network since one could essentially
           digitize the network's nodes and links directly on top of it.
                         !" Network Map
                                                                    •Q
           The backdrop map must be a Windows enhanced metafile or bitmap created outside
           of EPANET.  Once imported, its features cannot be edited, although its scale and
           extent will  change as the  map window is zoomed and  panned.  For this reason
           metafiles work better than bitmaps since they will not loose resolution when re-
           scaled.  Most CAD and GIS programs have the ability to save their drawings and
           maps as metafiles.

           Selecting View » Backdrop from the Menu Bar will display a sub-menu  with the
           following commands:

              •   Load (loads a backdrop map file into the project)

              •   Unload (unloads the backdrop map from the project)

              •   Align (aligns the pipe network with the backdrop)

              •   Show/Hide (toggles the display of the backdrop on and off)

           When first loaded, the backdrop image is placed with its upper left corner coinciding
           with that of the network's  bounding rectangle. The backdrop can be re-positioned
           relative to the network map by selecting View » Backdrop » Align. This allows
           an outline of the pipe network to  be moved across the backdrop  (by moving the
           mouse with  the left button held down) until one decides that it lines up properly with
           the backdrop. The name of the backdrop file and  its current alignment are  saved
           along with the rest of a project's data whenever the project is saved to file.
                                         85

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          For best results in using a backdrop map:

              •  Use a metafile, not a bitmap.

              •  Dimension the network map so that its bounding rectangle has the
                 same aspect ratio (width-to-height ratio) as the backdrop.
7.4    Zooming the Map

          To Zoom In on the map:
              i.   Select View » Zoom In or click
on the Map Toolbar.
              2. To zoom in 100%, move the mouse to the center of the zoom area
                 and click the left button.
              3. To perform a custom zoom, move the mouse to the upper left corner
                 of the zoom  area and with the left  button pressed  down, draw a
                 rectangular outline  around the  zoom  area.  Then release the left
                 button.

          To Zoom Out on the map:
              i.   Select View » Zoom Out or click 1    on the Map Toolbar.
              2.  Move the mouse to the center of the new zoom area and click the left
                 button.
              3.  The map will be returned to its previous zoom level.
7.5    Panning the Map

          To pan the map across the Map window:
              i.   Select View » Pan or click I-*-1 on the Map Toolbar.
              2.  With the left button held down over any point on the map, drag the
                 mouse in the direction you wish to pan in.

              3.  Release the mouse button to complete the pan.

          To pan using the Overview Map (which is described in Section 7.7 below):
              i.  If not already visible, bring up the Overview Map by selecting View
                 » Overview Map.
              2.  Position the mouse  within the zoom window  displayed on the
                 Overview Map.
              3.  With the left button  held down, drag the  zoom window to a  new
                 position.
              4.  Release the  mouse button and the main map  will be  panned to an
                 area corresponding to that of the Overview Map's zoom window.
                                        86

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7.6
Finding an Object

    To find a node or link on the map whose ID label is known:

       i.  Select View » Find or click
                                                I on the Standard Toolbar.
              2.  In the Map Finder dialog box that appears, select Node or Link and
                  enter an ID label.

              3.  Click Find.

           If the node/link exists it will be highlighted on the map and in the Browser. If the
           map  is  currently zoomed  in  and the  node/link  falls outside  the  current map
           boundaries, the map will be panned so that the node/link comes into view. The Map
           Finder dialog will also list the ID labels of the links that connect to a found node or
           the nodes attached to a found link.

           To find a listing of all nodes that serve as water quality sources:

              i.  Select View » Find or click
                                         I on the Standard Toolbar.
              2.  In the Map Finder dialog box that appears, select Sources.
              3.  Click Find.

           The ID labels of all water quality source nodes will be listed in the Map Finder.
           Clicking on any ID label will highlight that node on the map.
7.7    Map Legends
               Chlorine

               0.20
               0.40
               0.60
               0.80
               rngrt.
                    There are three types of map legends that can be displayed. The
                    Node and Link Legends associate a color with a range of values
                    for the current parameter being viewed  on the map. The Time
                    Legend displays the clock  time of the  simulation time period
                    being viewed.  To display or hide any of these legends check or
                    uncheck the legend from  the View » Legends menu or right-
                    click over the  map and do the same from the popup menu that
                    appears. Double-clicking the mouse over it can also hide a visible
                    legend.
           To move a legend to another location:
               i.  Press the left mouse button over the legend.
               2.  With the button held down, drag the legend to its new location and
                  release the button.
                                         87

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To edit the Node Legend:
    i.  Either select View » Legends » Modify » Node or right-click
       on the legend if it is visible.
    2.  Use the Legend Editor dialog form that appears (see Figure 7.2) to
       modify the legend's colors and intervals.

A similar method is used to edit the Link Legend.

The  Legend Editor (Figure 7.2) is used to  set numerical ranges to which different
colors are assigned for viewing a particular parameter on the network map. It works
as follows:

    •  Numerical values, in increasing order, are entered in the edit boxes to
       define the ranges. Not all four boxes need to have values.

    •  To change a color, click on its color band in the Editor and then
       select a new color from the Color Dialog box that will appear.

    •  Click the Equal Intervals button to assign ranges based on dividing
       the range of the parameter at the current time period into equal
       intervals.

    •  Click the Equal Quantiles button to assign ranges so that there are
       equal numbers of objects within each range, based on values that
       exist at the current time period.

    •  The Color Ramp button is used to  select from a list of built-in color
       schemes.

    •  The Reverse Colors button reverses the ordering of the current set of
       colors (the color in the lowest range becomes that of the highest
       range and so  on).

    •  Check Framed if you want a frame drawn around the legend.
             Legend Editor
                Quality
                 CL20
                 OL40
                JOJBO
                 L80

                mg/L
Equal Intervals

Equal Jjuanlila*

Color Ramp .„ I
Reverse Colors
               Click on color    with to change
                                                      Cancel
                        Help
                    p" Framed
                       Figure 7.2 Legend Editor Dialog
                               88

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7.8    Overview Map
             a*0verview Map
The  Overview Map allows you to see where in
terms of the overall system the main network map
is currently focused. This zoom area is depicted by
the   rectangular  boundary  displayed  on  the
Overview Map.  As you drag this rectangle to
another position the view within the main map will
follow suit. The Overview Map can be toggled on
and  off by selecting View »  Overview Map.
Clicking the mouse on its title bar will update its
map image to match that of the main network map.
7.9    Map Display Options
           There are several ways to bring up the Map Options dialog form (Figure 7.3) used to
           change the appearance of the Network Map:
              •   select View » Options,

              •   click the Options button
                  window has the focus,
    on the Standard Toolbar when the Map
                  right-click on any empty portion of the map and select Options from
                  the popup menu that appears.
                        Map Options
                          Links

                          Label*

                          Notation

                          Symbols

                          Flow Airows

                          Background


                                 OK
                                                 Node Size
        I*** Propoitional In Value
        p* Display Border
           Display Junctions
      Cancel

                                  Figure 7.3 Map Options Dialog
                                         89

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The dialog contains a separate page, selected from the panel on the left side of the
form, for each of the following display option categories:

    •   Nodes (controls size of nodes and making size  be proportional to
       value)

    •   Links  (controls  thickness  of  links  and  making thickness be
       proportional to value)

    •   Labels (turns display of map labels on/off)

    •   Notation (displays or hides node/link ID labels and parameter values)

    •   Symbols (turns display of tank, pump, valve symbols on/off)

    •   Flow Arrows (selects visibility and style of flow direction arrows)

    •   Background (changes color of map's background)


Node Options

The Nodes page of the Map Options dialog controls how nodes are displayed on the
Network Map.

 Option	^£?£^E^!1.	
 Node Size          Selects node diameter
 Proportional to     Select if node size should increase as the viewed parameter
 Value             increases in value
 Display Border     Select  if a  border  should  be  drawn around  each  node
                    (recommended for light-colored backgrounds)
 Display Junctions   Displays junction nodes (all junctions will be hidden unless
                    this option is  checked).
Link Options

The  Links page of the Map Options dialog controls how links are displayed on the
map.

_Option	D?s,£!2Pl!°!l,	
 Link Size            Sets thickness of links displayed on map
 Proportional to       Select if link thickness should increase as the viewed
 Value               parameter increases in value
                               90

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Label Options

The Labels page of the Map Options dialog controls how labels are displayed on the
map.
 Option _ ^£^£3^i^
 Display Labels        Displays map labels (labels will be hidden unless this
                      option is checked)
 Use Transparent      Displays label with a transparent background (otherwise an
 Text                 opaque background is used)
 At Zoom Of          Selects minimum zoom at which labels should be
                      displayed; labels will be hidden at zooms smaller than this
                      unless they are meter labels
Notation Options

The  Notation  page of the Map  Options  dialog  form determines what kind of
annotation is provided alongside of the nodes and links of the map.
 Display Node IDs        Displays node ID labels
 Display Node Values     Displays value of current node parameter being viewed
 Display Link IDs         Displays link ID labels
 Display Link Values      Displays values of current link parameter being viewed
 Use Transparent Text     Displays text with a transparent background (otherwise
                         an opaque background is used)
 At Zoom Of             Selects minimum zoom at which notation should be
                         displayed; all notation will be hidden at zooms smaller
                         than this

Note:  Values of the current viewing parameter at only specific nodes and links can
       be displayed by creating Map Labels with meters for those objects.  See
       Sections 6.2 and 6.4 as well as Table 6.7.
                              91

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Symbol Options

The Symbols page of the Map Options dialog determines which types of objects are
represented with special symbols on the map.

^Option	D^l£nPli£IL	
 Display Tanks          Displays tank symbols
 Display Pumps          Displays pump symbols
 Display Valves         Displays valve symbols
 Display Emitters        Displays emitter symbols
 Display Sources         Displays + symbol for water quality sources
 At Zoom Of            Selects minimum zoom at which symbols should be
                        displayed; symbols will be hidden at zooms smaller than
                        this
Flow Arrow Options
The Flow Arrows  page of the Map  Options  dialog controls how flow-direction
arrows are displayed on the network map.
 Arrow Style        Selects style (shape) of arrow to display (select None to hide
                    arrows)
 Arrow Size         Sets arrow size
 At Zoom Of        Selects minimum zoom at which arrows should be
                    displayed; arrows will be hidden at zooms smaller than this

Note:  Flow direction  arrows  will only be displayed  after a network has been
       successfully analyzed (see Section 8.2 Running an Analysis).
Background Options
The Background page of the Map Options dialog offers a selection of colors used to
paint the map's background with.
                              92

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CHAPTER 8  - ANALYZING  A  NETWORK
           After a network has been suitably described, its hydraulic and water quality behavior
           can be analyzed. This chapter describes how to specify options to use in the analysis,
           how to run the analysis and how  to trouble shoot problems that might have occurred
           with the analysis.
8.1    Setting Analysis Options

           There are five categories of options that control how EPANET analyzes a network:
           Hydraulics, Quality, Reactions, Times, and Energy. To set any of these options:

               i.  Select the Options category from the Data Browser or select Project
                   » Analysis Options from the menu bar.

               2.  Select Hydraulics, Quality, Reactions, Times,  or Energy from the
                   Browser.

               3.  If the Property Editor is not already visible, click the Browser's Edit

                   button     I (or hit the Enter key).

               4.  Edit your option choices in the Property Editor.

           As you are editing a category of options in the Property Editor you can move to the
           next or previous category by  simply hitting the Page  Down or Page Up keys,
           respectively.


           Hydraulic Options

           Hydraulic  options control how the hydraulic computations  are carried out. They
           consist of the following items:


            Option                Description

              .      .              Units in which nodal demands and link flow rates are expressed.
               w                  Choosing units in gallons, cubic feet,  or acre-feet implies that the
                                  units for all other network quantities are Customary US.
                                  Selecting liters or cubic meters causes all other units to be SI
                                  metric. Use caution when changing flow units as it might affect
                                  all other data supplied to the project. (See Appendix A, Units of
                                  Measurement.)

            Headless Formula      Formula used to compute headless as a function of flow rate in a
                                  pipe. Choices are:
                                    •   Hazen-Williams
                                    •   Darcy-Weisbach
                                    •   Chezy-Manning
                                  Because each formula measures pipe roughness differently,
                                  switching formulas might require that all pipe roughness
                                  coefficients be updated.
                                           93

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 Specific Gravity


 Relative Viscosity


 Maximum Trials



 Accuracy
 If Unbalanced
Note:
                Ratio of the density of the fluid being modeled to that of water at
                4 deg. C (unitless).

                Ratio of the kinematic viscosity of the fluid to that of water at 20
                deg. C (1.0 centistokes or 0.94 sq ft/day) (unitless).

                Maximum number of trials used to solve the nonlinear equations
                that govern network hydraulics at a given point in time.
                Suggested value is 40.

                Convergence criterion used to signal that a solution has been
                found to the nonlinear equations that govern network hydraulics.
                Trials end when the sum of all flow changes divided by the sum
                of all link flows is less than this number. Suggested value is
                0.001.

                Action to take if a hydraulic solution is not found within the
                maximum number of trials. Choices are STOP to stop the
                simulation at this point or CONTINUE to use another 10 trials,
                with no  link status changes allowed, in an attempt to achieve
                convergence.

                ID label of a time pattern to be applied to demands at those
                junctions where no time pattern is specified. If no such pattern
                exists then demands will not vary at these locations.

                Global multiplier applied to all demands to make total system
                consumption vary up or down by a fixed amount. E.g., 2.0
                doubles all demands, 0.5 halves them, and 1.0 leaves them as is.

                Power to which pressure is raised when computing the flow
                through an emitter device. The textbook value for nozzles and
                sprinklers is  1A. This may not apply to pipe leakage. Consult the
                discussion of Emitters in Section 3.1 for more details.

                Amount of status information to report after an analysis is made.
                Choices are:
                   •   NONE (no status reporting)
                   •   YES (normal status reporting - lists all changes in link
                       status throughout the simulation)
                   •   FULL (full reporting - normal reporting plus the
                       convergence error from each trial of the hydraulic
                       analysis made in each time period)

                Full status reporting is only useful for debugging purposes.
Choices for Hydraulic Options can also be set from the Project » Defaults
menu and saved for use with all future projects (see Section 5.2).
 Default Pattern



 Demand Multiplier



 Emitter Exponent




 Status Report
                                  94

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Water Quality Options

Water Quality Options  control how the water quality analysis is carried out. They
consist of the following:
 Option
 Parameter
 Mass Units
 Relative
 Diffusivity
 Trace Node
 Quality Tolerance
Description
Type of water quality parameter being modeled. Choices include:
•   NONE (no quality analysis),
•   CHEMICAL (compute chemical concentration),
•   AGE (compute water age),
•   TRACE (trace the percent of flow originating from a specific
    node).

In lieu of CHEMICAL, you can enter the actual name of the
chemical being modeled (e.g., Chlorine).

Mass units used to express concentration. Choices are mg/L or (o,g/L.
Units for Age and Trace analyses are fixed at hours and percent,
respectively.

Ratio of the molecular diffusivity of the chemical being modeled to
that of chlorine at 20 deg. C (0.00112 sq ft/day). Use 2 if the
chemical diffuses twice as fast as chlorine, 0.5 if hah" as fast, etc.
Applies only when modeling mass transfer for pipe wall reactions.
Set to zero to ignore mass transfer effects.

ID label of the node whose flow is being traced. Applies only to flow
tracing analyses.

Smallest change in quality that will cause a new parcel of water to be
created in a pipe.  A typical setting might be 0.01 for chemicals
measured in mg/L as well as water age and source tracing.
Note:   The Quality Tolerance determines when the quality of one parcel of water is
        essentially the same  as another parcel. For chemical analysis this might be
        the detection limit of the procedure used to measure the chemical, adjusted
        by a suitable factor of safety. Using too large a value for this tolerance might
        affect simulation accuracy. Using too small a value will affect computational
        efficiency. Some experimentation with this setting might be called for.
                                 95

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Reaction Options

Reaction Options set the types of reactions that apply to  a water quality analysis.
They include the following:
 Option
Description
 Bulk Reaction
 Order
 Wall Reaction
 Order
 Global Bulk
 Coefficient
 Global Wall
 Coefficient
 Limiting
 Concentration
 Wall Coefficient
 Correlation
Power to which concentration is raised when computing a bulk flow
reaction rate. Use 1 for first-order reactions, 2 for second-order
reactions, etc. Use any negative number for Michaelis-Menton
kinetics. If no global or pipe-specific bulk reaction coefficients are
assigned then this option is ignored.

Power to which concentration is raised when computing a bulk flow
reaction rate. Choices are FIRST (1) for first-order reactions or
ZERO (0) for constant rate reactions. If no global or pipe-specific
wall reaction coefficients are assigned then this option is ignored.

Default bulk reaction rate coefficient (Kb) assigned to all pipes. This
global coefficient can be overridden by editing this property for
specific pipes. Use a positive number for growth, a negative number
for decay, or 0 if no bulk reaction occurs. Units are concentration
raised to the (1-n) power divided by days, where n is the bulk
reaction order.

Wall reaction rate coefficient (Kw) assigned to all pipes. Can be
overridden by editing this property for specific pipes. Use a positive
number for growth, a negative number for decay, or 0 if no wall
reaction occurs. Units are ft/day (US) or m/day (SI) for first-order
reactions and mass/sq ft/day (US) or mass/sq m/day (SI) for zero-
order reactions.

Maximum concentration that a substance can grow to or minimum
value it can decay to. Bulk reaction rates will be proportional to the
difference between the current concentration and this value. See
discussion of Bulk Reactions in Section 3.4 for more details. Set to
zero if not applicable.

Factor correlating wall reaction coefficient to pipe roughness.  See
discussion of Wall Reactions in Section 3.4 for more details. Set to
zero if not applicable.
                                  96

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Times Options

Times options set values for the various  time steps used  in  an extended period
simulation. These  are  listed below  (times can be  entered as decimal  hours or in
hours:minutes notation):
 Option
Description
 Total Duration


 Hydraulic Time Step


 Quality Time Step


 Pattern Time Step


 Pattern Start Time



 Reporting Time Step


 Report Start Time


 Starting Time of Day


 Statistic
Total length of a simulation in hours. Use 0 to run a single
period (snapshot) hydraulic analysis.

Time interval between re-computation of system hydraulics.
Normal default is 1 hour.

Time interval between routing of water quality constituent.
Normal default is 5 minutes (0:05 hours).

Time interval used with all time patterns. Normal default is 1
hour.

Hours into all time patterns at which the  simulation begins
(e.g., a value of 2 means that the simulation begins with all
time patterns starting at their second hour). Normal default is 0.

Time interval between times at which computed results are
reported. Normal default is 1 hour.

Hours into simulation at which computed results begin to be
reported. Normal default is 0.

Clock time (e.g., 7:30 am, 10:00 pm) at  which simulation
begins. Default is 12:00 am (midnight).

Type of statistical processing used to summarize the results of
an extended period simulation. Choices are:

    •   NONE (results reported at each reporting time step)

    •   AVERAGE (time-averaged results reported)

    •   MINIMUM (minimum value results reported)

    •   MAXIMUM (maximum value results reported)

    •   RANGE (difference between maximum and minimum
        results reported)

Statistical processing is applied to all node and link results
obtained between the Report Start Time  and the Total
Duration.
Note:   To run a single-period hydraulic analyses (also called a snapshot analysis)
        enter 0 for Total Duration.  In  this case entries for all of the  other time
        options, with the exception of Starting Time  of Day, are not used. Water
        quality analyses always require that a non-zero  Total Duration be specified.
                                 97

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           Energy Options

           Energy Analysis Options provide default values used to compute pumping energy
           and cost when no specific energy parameters are assigned to a given pump. They
           consist of the following:


            Option                   Description

            Pump Efficiency (%)       Default pump efficiency.

            Energy Price per Kwh      Price of energy per kilowatt-hour. Monetary units are not
                                    explicitly represented.

            Price Pattern              ID label of a time pattern used to represent variations in
                                    energy price with time. Leave blank if not applicable.

            Demand Charge           Additional energy charge per maximum kilowatt usage.
8.2    Running an Analysis

           To run a hydraulic/water quality analysis:
              i.  Select  Project  » Run  Analysis or click I ^ I on  the  Standard
                  Toolbar.

              2.  The  progress of the analysis will be displayed in a Run Status
                  window.
              3.  Click OK when the analysis ends.
           If the analysis runs successfully the m I icon will appear in the Run Status section
           of the Status Bar at the bottom of the EPANET workspace. Any error or warning
           messages will appear in a Status Report window. If you edit the properties of the
           network after a  successful run has been made, the faucet icon changes to a broken
           faucet indicating that the  current  computed results no longer apply to the modified
           network.
8.3    Troubleshooting Results

           EPANET  will issue specific Error and  Warning  messages when problems are
           encountered in running a hydraulic/water quality analysis (see Appendix B for a
           complete listing). The most common problems are discussed below.


           Pumps Cannot Deliver Flow or Head

           EPANET will issue a warning message when a pump is asked to operate outside the
           range of its pump curve. If the pump is required to deliver more head than its shutoff
           head, EPANET will close the pump down. This might lead to portions of the network
           becoming disconnected from any source of water.
                                         98

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Network is Disconnected

EPANET classifies a network as being disconnected if there is no way to provide
water to all nodes that have demands. This can occur if there is no path of open links
between a junction with demand and either a reservoir,  a tank, or a junction with a
negative  demand.  If the problem is caused by a  closed  link  EPANET  will still
compute a hydraulic solution (probably with extremely large negative pressures) and
attempt to identify the problem link in its Status Report. If no connecting link(s) exist
EPANET will be unable to solve the hydraulic equations for flows and pressures and
will return an Error 110 message when an  analysis is made.  Under an  extended
period simulation it is  possible for nodes to become disconnected as links change
status overtime.


Negative  Pressures Exist

EPANET will issue a  warning message when it encounters negative pressures at
junctions  that have  positive  demands. This usually indicates  that there is some
problem with the way the network has been designed or operated. Negative pressures
can occur when portions of the network can only receive  water through links that
have been closed off. In such cases an additional warning message about the network
being disconnected is also issued.


System Unbalanced

A System Unbalanced condition can  occur when EPANET  cannot converge to a
hydraulic solution in some time period within its allowed maximum number of trials.
This situation can occur when valves, pumps, or pipelines keep switching their status
from  one trial  to  the  next as the search for a hydraulic solution proceeds. For
example, the pressure limits that control the status of a  pump may be set too close
together.  Or a pump's head curve might be too flat causing it to keep shutting  on and
off.

To eliminate the unbalanced condition one can try to increase the allowed maximum
number of trials  or loosen the convergence accuracy requirement. Both of these
parameters are set with the project's Hydraulic Options.  If the unbalanced condition
persists, then another hydraulic option, labeled "If Unbalanced", offers two ways to
handle it.  One is to terminate the entire analysis once the condition is encountered.
The other is to continue seeking a hydraulic solution for another  10 trials with  the
status of all links frozen to their current values. If convergence is achieved then a
warning message is issued about the system possibly being  unstable. If convergence
is not achieved then a  "System Unbalanced" warning message is issued.  In either
case, the analysis will proceed to the next time period.

If an analysis in a given time period ends with the system unbalanced then the user
should recognize  that  the hydraulic results produced for  this  time  period  are
inaccurate. Depending on circumstances, such as errors in flows into or out of storage
tanks, this might affect the accuracy of results in all future periods as well.
                               99

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Hydraulic Equations Unsolvable

Error 110 is issued if at some point in an analysis the set of equations that model flow
and energy balance in the network cannot be solved. This can occur when some
portion of a system demands water but has no links physically connecting it to any
source  of water. In such a case EPANET will also  issue warning messages about
nodes being disconnected. The equations might also be unsolvable  if unrealistic
numbers were used for certain network properties.
                              100

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CHAPTER 9 - VIEWING  RESULTS
           This chapter describes the different ways in which the results of an analysis as well
           as the basic network input data can be viewed. These include different map views,
           graphs, tables, and special reports.
9.1     Viewing Results on the Map

           There are several ways in which database values and results of a simulation can be
           viewed directly on the Network Map:

              •   For the current settings on the Map Browser (see Section 4.6), the
                  nodes and links of the map will be colored according to the color-
                  coding used in the  Map  Legends  (see Section 7.6).  The map's
                  coloring will be updated as a new time period is  selected in the
                  Browser.

              •   When the Flyover Map Labeling program preference is selected (see
                  Section 4.9), moving the mouse over any node or link will display its
                  ID label and the value of the current viewing parameter for that node
                  or link in a hint-style box.

              •   ID labels and viewing parameter values can be displayed next to all
                  nodes and/or  links by selecting the  appropriate options on  the
                  Notation page of the Map Options dialog form (see Section 7.8).

              •   Nodes or  links meeting a  specific  criterion can be identified by
                  submitting a Map Query (see below).

              •   You can animate the display  of results on the  network map either
                  forward or backward  in time by using the Animation buttons on the
                  Map Browser. Animation  is  only  available  when a node or  link
                  viewing parameter is a computed value (e.g., link flow rate can be
                  animated but diameter cannot).

              •   The map can be printed, copied to the Windows clipboard, or saved
                  as a DXF file or Windows metafile.


           Submitting a Map Query

           A Map Query identifies nodes or links  on the network map that meet a specific
           criterion (e.g., nodes with pressure less than 20 psi, links with velocity above 2 ft/sec,
           etc.). See Figure 9.1 for an example. To submit a map query:
                                         101

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                                       Dai 1, 3:00 PM
                  Figure 9.1 Results of a Map Query
l.  Select a time period in which to query the map from the  Map
    Browser.
                                    on the Map Toolbar.
    2.  Select View » Query or click
    3.  Fill in the following information  in the Query dialog  form that
       appears:

       •   Select whether to search for Nodes or Links

       •   Select a parameter to compare against

       •   Select Above, Below, or Equals

       •   Enter a value to compare against
    4.  Click the Submit button. The objects that meet the criterion will be
       highlighted on the map.
    5.  As a new time period is selected in the Browser, the query results are
       automatically updated.
    6.  You can submit another query using the  dialog box or close it by
       clicking the button in the upper right corner.

After the Query box is closed the map will revert back to its original display.
                           102

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9.2    Viewing Results with a Graph
           Analysis results, as well as  some design parameters, can be viewed using several
           different types of graphs. Graphs can be printed, copied to the Windows clipboard, or
           saved as a data file or Windows metafile. The following types of graphs can be used
           to view values for a selected parameter (see Figure 9.2 for examples of each):
            Type of Plot
            Time Series Plot

            Profile Plot

            Contour Plot


            Frequency Plot

            System Flow
Description
Plots value versus time

Plots value versus distance

Shows regions of the map
where values fall within
specific intervals
Plots value versus fraction of
objects at or below the value
Plots total system production
and consumption versus time
Applies To
Specific nodes or links
over all time periods
A list of nodes at a
specific time
All nodes at a specific
time

All nodes or links at a
specific time
Water demand for all
nodes over all time periods
           Note:  When only a single node or link is graphed in a Time Series Plot the graph
                  will also display any measured data residing in a Calibration File that has
                  been registered with the project (see Section 5.3).
           To create a graph:

               i.  Select Report » Graph or click
                     on the Standard Toolbar.
               2.  Fill in the choices on the Graph Selection dialog box that appears.
               3.  Click OK to create the graph.

           The Graph Selection dialog, as pictured in Figure 9.3, is used to select a type of graph
           and its  contents  to display.  The choices available  in  the  dialog consist of the
           following:
            Item
            Graph Type
            Parameter
            Time Period

            Object Type

            Items to Graph
 Description
 Selects a graph type
 Selects a parameter to graph
 Selects a time period to graph (does not apply to Time
 Series plots)
 Selects either Nodes or Links (only Nodes can be graphed
 on Profile and  Contour plots)
 Selects items to graph (applies only to Time Series and
 Profile plots)
                                          103

-------
u Time Series Plot - Pressure lor Node 12
    126.0

   J24.0

    122.0-
  
-------
1 & System Flow i
2000.0-
g> 1500.0
Q_
2-iooo.o
S. 500.0-
0.0

D 	 D 	 D 	 D-
A A
A A

=0= Produced A Consumed |
n 	 n
o 	 D 	 g-g-Q 	 n 	 Q 	 D 	 p i i
A A A A '
A A ;; ;
A- A i i' A
" A A : A:A
i A A A A ::
. 1 :
0
5 10 15 20
Time (hours)

• Contour Plot - at 1 6:00 Mrs |~~ 1
— ~x
N
^1
\ /"\
^ \

1
~^




;
\ l^_





\ m Quality
1
I n 0.^0
-0.40

- 0.60
j - 0.80
y' U mgi;|_
I
\
\
\v
\
«.
Figure 9.2  Continued From Previous Page
                 105

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           (•  Time Series

              Profile Plol

           C  Contour Plot

           f~"  Frequency Plot

               yslem Flow
                       Figure 9.3  Graph Selection Dialog
Time Series  plots and Profile  plots require one or more objects be  selected for
plotting. To select items into the Graph Selection dialog for plotting:
    i.   Select the object (node or link) either on the Network Map or on the
        Data Browser. (The Graph Selection  dialog  will remain visible
        during this process).
    2.   Click the Add button  on the  Graph  Selection dialog to add the
        selected item to the list.

In place of Step 2, you can also drag the object's label from the Data Browser onto
the Form's title bar or onto the Items to Graph list box.

The other buttons on the Graph Selection dialog form are used as follows:
 Button
Purpose
 Load (Profile Plot Only)
 Save (Profile Plot Only)
 Delete
 Move Up
 Move Down
Loads a previously saved list of nodes
Saves current list of nodes to file
Deletes selected item from list
Moves selected item on list up one position
Moves selected item on list down one position
                               106

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To customize the appearance of a graph:
    i.  Make the graph the active window (click on its title bar).
    2.  Select Report » Options, or click
on the Standard Toolbar, or
       right-click on the graph.

    3.  For a Time Series, Profile, Frequency or System Flow plot, use the
       resulting Graph Options dialog (Figure 9.4) to customize the graph's
       appearance.
    4.  For a Contour plot  use  the  resulting  Contour Options dialog to
       customize the plot.

Note:  A Time Series, Profile, or Frequency plot can be zoomed by holding down
       the Ctrl key while drawing a zoom rectangle with the  mouse's left button
       held down. Drawing the rectangle from  left to right zooms in, drawing from
       right  to left zooms out.  The  plot can also be  panned in any  direction by
       holding down the Ctrl key and moving the mouse across the plot with the
       right button held down.

The Graph Options dialog form (Figure 9.4) is used to customize the appearance of
an X-Y graph. To use the dialog box:

    i.  Select from among the five tabbed pages that cover the following
       categories of options:

       •   General

       •   Horizontal Axis

       •   Vertical Axis

       •   Legend

       •   Series
    2.  Check the Default box  if you wish  to use the current settings as
       defaults for all new graphs as well.
    3.  Select OK to accept your selections.

The items contained on each page of the Graph Options dialog are as follows:


General Page
 Option              Description
 Panel Color         Color of the panel which surrounds the graph's plotting area
 Background Color    Color of graph's plotting area
 View in 3D          Check if graph should be drawn in 3D
 3D Effect Percent    Degree to which 3D effect is drawn
 Main Title           Text of graph's main title
 Font                Changes the font used for the main title
                              107

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          Graph Options
            General  Horizontal Axis  Vertical Axis  Legend  Series
                    Lines   Markers  Patterns  Labels
            r"el
Default
Cancel
Help
                      Figure 9.4  Graph Options Dialog
Horizontal and Vertical Axis Pages
 Option
     Description
 Minimum

 Maximum

 Increment
 Auto Scale

 Gridlines
 Axis Title
 Font
     Sets minimum axis value (minimum data value is shown in
     parentheses). Can be left blank.
     Sets maximum axis value (maximum data value is shown in
     parentheses). Can be left blank.
     Sets increment between axis labels. Can be left blank.
     If checked then Minimum, Maximum, and Increment
     settings are ignored.
     Selects type of gridline to draw.
     Text of axis title
     Click to select a font for the axis title.
                              108

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Legend Page

 Option              Description
 Position             Selects where to place the legend.
 Color               Selects color to use for legend background.
 Symbol Width       Selects width to use (in pixels) to draw symbol portion of
                     the legend.
 Framed             Places a frame around the legend.
 Visible              Makes the legend visible.


Series Page

The Series page (see Figure 9.4) of the Graph Options dialog controls how individual
data series (or curves) are displayed on a graph. To use this page:

    •   Select a data series to work with from the Series combo box.

    •   Edit the title used to identify this series in the legend.

    •   Click the Font button to change the font used for the legend. (Other
       legend properties are selected on the Legend page of the dialog.)

    •   Select a property of the data series you would like to modify. The
       choices are:
           •   Lines

           •   Markers

           •   Patterns

           •   Labels

(Not all properties are available for some types of graphs.)

The data series properties that can be modified include the following:
                               109

-------
Category
Lines



Option
Style
Color
Size
Visible
Description
Selects line
Selects line
Selects line
Determines

style.
color.
thickness (only for solid
if line is visible.



line style).

 Markers
Style
Color
Size
Visible
Selects marker style.
Selects marker color.
Selects marker size.
Determines if marker is visible.
 Patterns      Style            Selects pattern style.
              Color            Selects pattern color.
              Stacking         Not used with EPANET.

 Labels       Style            Selects what type of information is displayed in
                               the label.
              Color            Selects the color of the label's background.
              Transparent      Determines if graph  shows through label or not.
              Show Arrows     Determines if arrows are displayed on pie  charts.
              Visible           Determines if labels are visible or not.
The Contour Options dialog form (Figure 9.5) is used to customize the appearance of
a contour graph. A description of each option is provided below:
                               110

-------
          Contour Plot Options
             Legend
               jDisplay Legend:

                   Modify Legend...
             Network Backdrop
             Foreground
                            Style
                            |>" Filled Contours

                            |'" Line Contours
                             Contour Lines
                             Thickness   |1 ^|
                     Figure 9.5 Contour Plot Options Dialog
Category
Option
Description
Legend

Network
Backdrop
Display Legend
Modify Legend

Foreground
Background
Link Size
Toggles display of legend on/off
Changes colors and contour intervals

Color of network image displayed on plot
Background color used for line contour plot
Thickness of lines used to display network
Style
Filled Contours
Line Contours
Plot uses colored area-filled contours
Plot uses colored line contours
Contour Lines    Thickness
                Lines per Level
                  Thickness of lines used for contour intervals
                  Number of sub-contours per major contour
                  level
Default
                  Saves choices as defaults for next contour
                  plot
                              111

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9.3    Viewing Results with a Table

           EPANET allows you to view selected project data and analysis results in a tabular
           format:

               •   A Network Table lists properties and results for all nodes or links at
                  a specific period of time.

               •   A Time Series Table lists properties and results for a specific node or
                  link in all time periods.

           Tables can be printed, copied to the Windows clipboard, or saved to file. An example
           table is shown in Figure 9.6.

           To create a table:
               i.  Select View » Table or click     on the Standard Toolbar.
               2.  Use the Table Options dialog box that appears to select:

                  •   the type of table

                  •   the quantities to display in each column

                  •   any filters to apply to the data
m Nelwoik Table - at 4:00 Mrs H 1
Node ID
Demand
GPM
Head
ft
Piessuie
psi
Chloiine *. 1
mi/L p
0,00 1010,17
June 11
June 12
June 13
June 21
June 22
June 23
June 31
210-00
210.00
140.00
210.00
200.00
210.00
f^olii
992-42
980.17
977.08
977.24
976.29
975.76
g^O^
122.37
121.40
122.23
120.13
121.88
123.82
117.13
0.85
0.78
0.30
0.74
0.49
0.30
0.53 ^J
                              Figure 9.6  Example Network Nodes Table
           The Table Options dialog form has three tabbed pages as shown in Figure 9.7. All
           three pages are available when a table is first created. After the table is created, only
           the Columns and Filters tabs will appear. The  options available on each page are as
           follows:
                                          112

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              Table Selection
                        Columns I Filters
                    (•" Nrtmik       at

                    f*" Network Links at
10:00 Mrs
                    (*"* Time      For node

                    ''~" Time      for link
10
                                   Cancel

                       Figure 9.7 Table Selection Dialog
Type Page

The  Type page of the Table Options dialog is used to select the type of table to
create. The choices are:

    •  All network nodes at a specific time period

    •  All network links at a specific time period

    •  All time periods for a specific node

    •  All time periods for a specific link

Data fields are available for selecting the time period or node/link to which the table
applies.


Columns Page

The  Columns page  of the  Table Options  dialog  form  (Figure  9.8)  selects  the
parameters that are displayed in the table's columns.

    •  Click the checkbox next to the name of each parameter you wish to
       include in the table, or if the item is already selected, click in the box
       to deselect it. (The keyboard's Up and Down Arrow keys can be used
       to move between the parameter names, and the spacebar can be used
       to select/deselect choices).
                               113

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       To sort a  Network-type  table with  respect  to  the values of  a
       particular parameter, select the parameter from the list and check off
       the Sorted By box at the bottom of the form. (The sorted parameter
       does not have to be selected as one of the columns in the table.) Time
       Series tables cannot be sorted.
              Table ielection
                 If pa           J Filtori (

                    Select which columns to include in the
                            |~~ Elevilion
                            |~~      Demand
                               Initial Quality
                               Demand
                               Head

                            K Chlorine
                               Soiled bf Pressure
                                    Cancel
Help
             Figure 9.8 Columns Page of the Table Selection Dialog
Filters Page

The  Filters  page of the Table Options dialog form (Figure  9.9) is used to define
conditions for selecting items to appear in a table. To filter the contents of a table:

    •  Use the controls at the top of the page to create a condition (e.g.,
       Pressure Below 20).

    •  Click the Add button to add the condition to the list.

    •  Use the Delete button to remove a selected condition from the list.

Multiple  conditions used to  filter the table are connected by AND's. If a table has
been filtered, a re-sizeable panel will appear at the bottom indicating how many items
have satisfied the filter conditions.
                               114

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1 Table Selection
T,
H» | Fillers |


Pressure J j Below jj
Pressure Below 20
^^AdH^J

OK 1 Cancel





20
Delete







LJfeJE_l



                         Figure 9.9  Filters Page of the Table Selection Dialog

           Once a table has been created you can add/delete columns or sort or filter its data:
                                                       on the Standard Toolbar or
Select Report » Options or click
right-click on the table.
Use the Columns and Filters pages of the Table Selection dialog
form to modify your table.
9.4    Viewing Special Reports
           In addition to  graphs  and tables, EPANET can generate  several other specialized
           reports. These include:
               •   Status Report
               •   Energy Report
               •   Calibration Report
               •   Reaction Report
               •   Full Report
           All of these reports can be printed, copied to  a file, or copied to the  Windows
           clipboard (the Full Report can only be saved to file.)
                                          115

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Status Report

EPANET writes all error and warning messages generated during an analysis to a
Status Report (see Figure 9.10). Additional information on when network objects
change status is also written to this report if the Status Report option in the project's
Hydraulics  Options was set to Yes or Full.  To view a status report  on the most
recently completed analysis select Report » Status from the main menu.
 Status Report
 12:00:  Balanced after 3 trials

 12:33:  Pump 9 changed by Tank 2 control
 12:33:  Balanced after 4 trials
 12:33:  Reservoir 9 is closed
 12:33:  Tank 2 is Emptying at 140.00  ft
 12:33:  Pump 9 changed from open to closed

 13:00:  Balanced after 1 trials

 14:00:  Balanced after 2 trials

 15:00:  Balanced after 1 trials

 16:00:  Balanced after Z trials

 17:00:  Balanced after 1 trials

 18:00:  Balanced after 2 trials

 19:00:  Balanced after 1 trials

 20:00:  Balanced after 2 trials
                   Figure 9.10 Excerpt from a Status Report
Energy Report

EPANET can generate an Energy Report that displays statistics about the energy
consumed by each pump and the cost of this energy usage over the duration of a
simulation (see Figure 9.11). To generate an Energy Report select Report » Energy
from the main menu. The report has two tabbed pages. One displays energy usage by
pump in a tabular format. The second compares a selected energy statistic between
pumps using a bar chart.
                              116

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g Energy Report
Table Chart
P*
Pump Uti
10 1
335
Total Cost |
Demand Charge j


ircenl Average
ization Efficiency
58.33 75-00
29-51 75-00



Kw-hr Average
/Mgal KwaKs
314-07 62-01
394-83 309.49



Peak Cost
KwaHs /day
62-73 0-00
310-86 0-00
I 0.00
0.00
                      Figure 9.11  Example Energy Report
Calibration Report

A Calibration Report can  show how  well EPANET's simulated results  match
measurements taken from the system being modeled. To create a Calibration Report:
    l.  First  make  sure  that  Calibration  Data for the  quantity  being
       calibrated has been registered with the project (see Section 5.3).
    2.  Select Report » Calibration from the main menu.
    3.  In the Calibration Report Options form that appears (see Figure
       9.12):

       •   select a parameter to calibrate against
       •   select the measurement locations to use in the report
    4.  Click OK to  create the report.

After the report  is created the Calibration Report Options form can be recalled to
change report options by  selecting Report » Options  or by clicking
                                                                       on the
Standard Toolbar  when  the  report is the current  active window in EPANET's
workspace.

A sample Calibration Report is shown  in Figure 9.13. It contains three tabbed pages:
Statistics, Correlation Plot, and Mean Comparisons.

Statistics Page

The  Statistics page of a Calibration  Report lists various error  statistics  between
simulated and observed values at each measurement location and for the network as a
whole. If a  measured value at a location was  taken  at a time in-between the
simulation's reporting time intervals then a simulated value for that time is found by
interpolating between the simulated values at either end of the interval.
                               117

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                  Calibration Report Options
                    "Calibrate Against
                                                 OK
                     Measured at Nodes:
                                                Cancel
                    PTT
                    F?19
                 Figure 9.12  Calibration Report Options Dialog
ji Calibration Report - Fluoride

Statistics j] Coin
'

Calibration

Location
11
19
25
34
Metnork
Correlation
U
Nation Plot ]

Statistics
Hum
Oils
19
20
20
19
70
Mean


Compaiisons ]



for Fluoride ±_
atts
Mean
0.49
0.15
0.15
0.92
0.13
Between Means:


Camp
Mean
0.44
0.54
0.69
0.95
0.65
0.895

Mean
Error
0.064
0.254
0.084
0.104
0.121


IMS
Error
0.102
0.371
0.145
0.180
0.229
i
_T
                    Figure 9.13 Example Calibration Report


The statistics listed for each measurement location are:
    •   Number of observations
    •   Mean of the observed values
    •   Mean of the simulated values
    •   Mean absolute error between each observed and simulated value
    •   Root mean square error (square root of the mean of the squared
       errors between the observed and simulated values).
                              118

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These statistics are also provided for the network as a whole (i.e., all measurements
and model errors pooled together). Also  listed is the correlation  between means
(correlation coefficient between the mean observed value and mean simulated value
at each location).

Correlation Plot Page

The Correlation Plot  page  of a Calibration Report displays  a scatter plot of the
observed and simulated values for each measurement  made at each location. Each
location is assigned a different color in the plot. The closer that the points come to the
45-degree angle line  on  the plot the closer is the match between observed and
simulated values.

Mean Comparisons Page

The Mean Comparisons  page of a Calibration  Report presents a bar chart that
compares the mean observed and mean simulated value for a calibration parameter at
each location where measurements were taken.
Reaction Report

A Reaction Report, available when modeling the fate of a reactive water quality
constituent, graphically  depicts  the  overall  average reaction  rates  occurring
throughout the network in the following locations:

    •  the bulk flow

    •  the pipe wall

    •  within storage tanks.

A pie chart shows what percent of the overall reaction rate is occurring in each
location. The  chart legend displays the average rates in  mass units per  hour. A
footnote on the chart shows the inflow rate of the reactant into the system.

The  information in the Reaction Report can show at  a glance what mechanism is
responsible for the majority of growth  or decay of a substance in the network. For
example, if one observes that most of the chlorine decay in a system is occurring in
the storage tanks and not at the walls of the pipes  then  one might infer that a
corrective  strategy  of pipe cleaning  and  replacement will  have  little  effect in
improving chlorine residuals.

A Graph Options dialog box can be called  up to modify the appearance of the pie
chart by selecting Report » Options or by clicking
by right-clicking anywhere on the chart.
on the Standard Toolbar, or
                               119

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Full Report
When the • • icon appears in the Run Status section of the Status Bar, a report of
computed results for all nodes, links  and time periods can be saved to file by
selecting Full  from the Report menu. This report, which can be viewed or printed
outside of EPANET using any text editor or word processor, contains the following
information:

    •  project title and notes

    •  a table listing the end nodes, length, and diameter of each link

    •  a table listing energy usage statistics for each pump

    •  a pair of tables for each time period listing computed values for each
       node (demand, head, pressure, and quality)  and for each link (flow,
       velocity, headless, and status).

This feature is useful mainly for documenting the final results of a network analysis
on small to moderately sized networks (full report files for large networks analyzed
over many time periods can easily consume dozens of megabytes of disk space). The
other reporting tools described in this chapter are available  for viewing computed
results on a more selective basis.
                               120

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CHAPTER  10 - PRINTING AND COPYING
           This chapter describes how to print, copy to the Windows clipboard, or copy to file
           the  contents of the currently active window in the EPANET workspace.  This can
           include the network map, a graph, a table, a report, or the properties of an object
           selected from the Browser.
10.1   Selecting a Printer
           To select a printer from among your installed Windows printers and set its properties:
               i.  Select File » Page Setup from the main menu.
               2.  Click the Printer button on the Page Setup dialog that appears (see
                  Figure  10.1).
               3.  Select a printer from the choices available in the  combo box in the
                  next dialog that appears.
               4.  Click the Properties button to select the printer's properties (which
                  vary with choice of printer).
               5.  Click OK on each dialog box to accept your selections.
10.2   Setting the Page Format
           To format the printed page:
              i.  Select File » Page Setup from the main menu.
              2.  Use the Margins page of the Page Setup dialog form that appears
                  (Figure 10.1) to:
                  •   Select a printer
                  •   Select the paper orientation (Portrait or Landscape)
                  •   Set left, right, top, and bottom margins
              3.  Use the Headers/Footers page of the dialog box to:
                  •   Supply the text for a header that will appear on each page
                  •   Indicate whether the header should be printed or not
                  •   Supply the text for a footer that will appear on each page
                  •   Indicate whether the footer should be printed or not
                  •   Indicate whether or not pages  should be numbered
              4.  Click OK to accept your choices.
                                         121

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                   Pago Setup
                     Margins I Headers/Footers j
                          Piintoi,
                       "Pop»i Sea	
                             B.5 "
                       Height: 11.0"
                       "0 rienlalion~~~~
                       
-------
10.5   Copying to the Clipboard or to a File

           EPANET can copy the text and graphics of the current window being viewed to both
           the Windows clipboard and to a file. Views that can be copied in this fashion include
           the Network Map, graphs,  tables,  and reports.  To copy the current view to the
           clipboard or to file:
                  Select Edit » Copy To from the main menu or click
              2.  Select choices from the Copy dialog that appears (see Figure 10.2)
                  and click its OK button.

              3.  If you selected to copy-to-file, enter the name of the file in the Save
                  As dialog box that appears and click OK.

           Use the Copy dialog as follows to define  how you want your data copied and to
           where:

              i.  Select a destination for the material  being copied (Clipboard or File)

              2.  Select a format to copy in:

                  •   Bitmap (graphics only)

                  •   Metafile (graphics only)

                  •   Data (text, selected cells in a table, or data used to construct a
                      graph)

              3.  Click OK to accept your selections or Cancel to cancel the copy
                  request.
                              Copy Contour Plot
                               ~Copy To	

                                 (• Clipboard


                                 r Filn
    -Copf At
     r
     r  Data (Tent)
                                    OK
Cancel
Help
                                     Figure 10.2 Copy Dialog
                                         123

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         124

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CHAPTER  11  -IMPORTING AND  EXPORTING
           This chapter introduces the concept of Project Scenarios and describes how EPANET
           can import and export these and other data, such as the network map and the entire
           project database.
11.1   Project Scenarios

           A Project  Scenario consists of a subset of the data that characterizes the current
           conditions under which a pipe network is being analyzed. A scenario can consist of
           one or more of the following data categories:

              •   Demands (baseline demand plus time patterns  for all categories) at
                  all nodes

              •   Initial water quality at all nodes

              •   Diameters for all pipes

              •   Roughness coefficients for all pipes

              •   Reaction coefficients (bulk and wall) for all pipes

              •   Simple and rule-based controls

           EPANET can compile a scenario  based on some or all of the data categories listed
           above, save the scenario to file, and read the scenario back in at a later time.

           Scenarios can provide more efficient and systematic analysis of design and operating
           alternatives. They can be used to examine the impacts of different loading conditions,
           search for optimal parameter estimates, and evaluate changes in operating  policies.
           The scenario files are saved as ASCII text and can be created or modified outside of
           EPANET using a text editor or spreadsheet program.
11.2   Exporting a Scenario

           To export a project scenario to a text file:

              l.  Select File » Export » Scenario from the main menu.

              2.  In the Export Data dialog form that appears (see Figure 11.1) select
                  the types of data that you wish to save.

              3.  Enter an optional description of the scenario you are saving in the
                  Notes memo field.
              4.  Select the OK button to accept your choices.

              5.  In the Save dialog box that next appears select a folder and name for
                  the scenario file. Scenario files use the default extension .SCN.

              6.  Click OK to complete the export.
                                         125

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                      Export Data
-Data to Eipnt	

  f~~  Nodal Demands

  |~*  Pipo Diameter!

  IT"  Pipo
                                                   Initial Quality

                                                   Reaction Coefficients
                        -Notes-
                         (Case 1: Baseline WQ Calibration
                                        OK
                            Cancel
Help
                                  Figure 11.1  Export Data Dialog
           The exported scenario  can be imported back into the  project at  a  later  time  as
           described in the next section.
11.3   Importing a Scenario
           To import a project scenario from a file:

              l.  Select File » Import » Scenario from the main menu.

              2.  Use the Open File dialog box that appears to select a scenario file to
                  import. The dialog's Contents panel will display the first several lines
                  of files as they are selected, to help locate the desired file.

              3.  Click the OK button to accept your selection.

           The data contained in the scenario file will replace any existing of the same kind in
           the current project.
11.4   Importing a Partial Network

           EPANET has the ability to import a geometric description of a pipe network in a
           simple text  format.  This description simply  contains the  ID labels  and  map
           coordinates of the nodes and the ID labels and end nodes of the links. This simplifies
           the process of using  other programs,  such as CAD and GIS  packages, to digitize
           network geometric data and then transfer these data to EPANET.
                                         126

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          The format of a partial network text file looks as follows, where the text between
          brackets (< >) describes what type of information appears in that line of the file:

           [TITLE]
          

           [JUNCTIONS]
          

           [PIPES]
          

           [COORDINATES]
          

           [VERTICES]
          

          Note that only junctions and pipes are represented. Other network elements, such as
          reservoirs and pumps, can either be imported as junctions or pipes  and converted
          later on or simply be added in later on. The user is responsible for transferring any
          data generated from a CAD or GIS package into a text file with the format shown
          above.

          In addition to this partial representation, a complete specification of the network can
          be placed in a file using the format described in Appendix C. This is the same format
          EPANET uses when a project is exported to a text file (see Section 11.7 below). In
          this case the file would also contain information on node and link properties, such as
          elevations, demands, diameters, roughness, etc.
11.5   Importing a Network Map

          To import the coordinates for a network map stored in a text file:
              l.  Select File » Import » Map from the main menu.
              2.  Select the file containing the map information from the Open File
                  dialog that appears.
              3.  Click OK to replace the current network map with the one described
                  in the file.
11.6   Exporting the Network Map

          The current view of the network map can be saved to file using either Autodesk's
          DXF (Drawing Exchange Format) format, the Windows enhanced metafile (EMF)
          format, or EPANET's own ASCII text (map) format. The DXF format is readable by
          many Computer Aided Design (CAD) programs. Metafiles can be inserted into word
                                        127

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           processing documents and loaded into drawing programs for re-scaling and editing.
           Both formats are vector-based and will not loose resolution when they are displayed
           at different scales.

           To export the network map at full extent to a DXF, metafile, or text file:
               l.  Select File » Export » Map from the main menu.
               2.  In the Map Export dialog form that appears (see Figure  11.2) select
                  the format that you want the map saved in.
               3.  If you select DXF format, you have a choice of how junctions will be
                  represented in the DXF file. They can be drawn as open circles, as
                  filled circles, or as filled squares. Not all DXF readers can recognize
                  the commands used in the DXF file to draw a filled circle.
               4.  After choosing a format, click OK and enter a name for the file in the
                  Save As dialog form that appears.
                        Map Export
                          -Eiporl Map To:
                             f  Tent File [.mapj

                             if*  Enhanced Metafile ( emf)

                             i*»'  Drawing Exchange File [.dxf]

                                ""Draw Junctions As: —
                                (*" Open

                                f* Filled circles

                                f* Filled squares
Cancel
        1
••^^•••'^'••••••"'•••fm
                                   Figure 11.2  Map Export Dialog
11.7   Exporting to a Text File
           To export a project's data to a text file:
               l.  Select File » Export » Network from the main menu.
               2.  In the Save dialog form that appears enter a name for the file to save
                  to (the default extension is .INP).
               3.  Click OK to complete the export.

           The  resulting file will  be written in  ASCII  text format, with the  various data
           categories and property  labels  clearly identified. It can be read back into EPANET
                                          128

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for analysis at another time by using either the File » Open or File » Import »
Network commands. Complete network descriptions using this input format can also
be created outside of EPANET using any text  editor or  spreadsheet program. A
complete specification of the .INP file format is given in Appendix C.

It is a good idea to  save an archive version  of your database in this format so you
have access to a human readable version of your data. However, for day-to-day use
of EPANET it is more efficient to save your data using EPANET's special project file
format (that creates a .NET file) by using the File » Save or File » Save As
commands. This format contains additional project information, such as the colors
and ranges chosen for the map legends, the set of map display options in effect, the
names of registered calibration data files, and any  printing options that were selected.
                              129

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              130

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CHAPTER 12 - FREQUENTLY ASKED  QUESTIONS



       How can I import a pipe network created with a CAD or GIS program?

           See Section 11.4.


       How do I model a groundwater pumping well?

           Represent the  well as a reservoir whose  head equals the piezometric head  of the
           groundwater aquifer. Then connect your pump from the reservoir to the rest of the
           network. You can add piping ahead of the pump to represent local losses around the
           pump.

           If you know the rate at which the well  is  pumping then an alternate approach is to
           replace the well - pump combination with a junction assigned a negative demand
           equal to the pumping rate. A time pattern  can also be assigned to the demand if the
           pumping rate varies overtime.


       How do I size a pump to meet a specific flow?

           Set the status of the pump to CLOSED. At the suction (inlet) node of the pump add a
           demand equal  to the required pump flow and place  a negative demand of the same
           magnitude at the discharge node. After analyzing the  network, the difference in heads
           between the two nodes is what the pump needs to deliver.


       How do I size a pump to meet a specific head?

           Replace the pump with a Pressure Breaker Valve oriented in the opposite direction.
           Convert the design head to an equivalent pressure and use this as the setting for the
           valve. After running the analysis the flow through  the valve becomes the pump's
           design flow.


       How can I enforce a specific schedule of source flows into the network from my
       reservoirs?

           Replace  the reservoirs with  junctions  that have negative  demands  equal  to the
           schedule of source flows. (Make sure there is at least one tank or remaining reservoir
           in the network, otherwise EPANET will  issue an error message.)


       How can I analyze fire flow conditions for a particular junction node?

           To determine the  maximum pressure available at a  node when the flow demanded
           must be increased to suppress a fire, add the fire flow to the node's normal demand,
           run the analysis, and note the resulting pressure at the node.
                                        131

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   To determine the maximum flow available at a particular pressure, set the emitter
   coefficient at the node to a large value (e.g., 100 times the maximum expected flow)
   and add the  required pressure head (2.3 times the pressure in psi) to the node's
   elevation.  After running the analysis, the available fire flow  equals the actual
   demand reported for the node minus any consumer demand that was assigned to it.


How do I model a reduced pressure backflow prevention valve?

   Use a General Purpose Valve with a headless curve that shows increasing head loss
   with decreasing flow. Information from the valve manufacturer should provide help
   in constructing the  curve. Place  a check valve (i.e., a short length of pipe whose
   status is set to CV) in series with the valve to restrict the direction of flow.


How do I model a pressurized pneumatic tank?

   If the pressure variation  in the tank  is negligible, use  a  very short, very wide
   cylindrical tank whose elevation is set close to the pressure head rating of the tank.
   Select the tank  dimensions so that  changes in  volume produce  only  very  small
   changes in water surface elevation.

   If the pressure  head  developed  in  the  tank  ranges  between HI and H2,  with
   corresponding volumes VI and V2, then use a cylindrical tank whose cross-sectional
   area equals (V2-V1)/(H2-H1).


How do I model a tank inlet that discharges above the water surface?

   Use the configuration shown below:
           Inlet

     O	M	(X        Outlet
           PSV
                       .
                      TJ
                              CV

   The tank's inlet consists of a Pressure Sustaining Valve followed by a short length of
   large diameter pipe. The pressure setting of the PSV should be 0, and the elevation of
   its end nodes should equal the elevation at which the true pipe connects to the tank.
   Use a Check Valve on the tank's outlet line to prevent reverse flow through it.


How do I determine initial conditions for a water quality analysis?

   If simulating existing  conditions monitored as part of a calibration study, assign
   measured values to the nodes where measurements were made and interpolate (by
   eye) to assign values to other locations. It is highly recommended that storage tanks
   and source  locations be included in the  set of locations where measurements are
   made.

   To simulate future conditions start with arbitrary initial values (except at the tanks)
   and run the analysis for a  number  of repeating demand pattern cycles  so  that the
                                  132

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    water quality results begin to repeat in a periodic fashion as well. The number of such
    cycles can be reduced if good initial estimates are made for the water quality in the
    tanks. For example, if modeling water age the initial value could be set to the tank's
    average residence time, which is approximately equal to the  fraction of its volume it
    exchanges each day.


How do I estimate values of the bulk and wall reaction coefficients?

    Bulk reaction coefficients can  be  estimated by performing a  bottle  test in the
    laboratory (see  Bulk Reactions  in  Section  3.4). Wall reaction rates  cannot  be
    measured directly. They must be back-fitted against calibration data collected from
    field studies  (e.g., using trial  and error to  determine coefficient values that produce
    simulation results that best match field observations). Plastic pipe and relatively new
    lined iron pipe are not expected to exert any significant wall demand for disinfectants
    such as chlorine and chloramines.


How can I model a chlorine booster station?

    Place the booster station at a junction node with zero or positive demand or at a tank.
    Select the node  into the Property Editor and click the ellipsis button in the Source
    Quality field to  launch the Source Quality Editor. In the editor,  set Source Type to
    SETPOINT BOOSTER and  set Source Quality to the chlorine  concentration that
    water leaving the node will be boosted to. Alternatively, if the booster station will use
    flow-paced addition of chlorine then set Source Type to FLOW PACED BOOSTER
    and Source Quality to the concentration  that will be  added to the  concentration
    leaving the node. Specify  a time pattern ID in the Time Pattern field if you wish to
    vary the boosting level with time.


How would I model THM growth in a network?

    THM growth can be modeled using first-order saturation kinetics. Select Options -
    Reactions from the Data Browser. Set the bulk  reaction order to  1 and the limiting
    concentration to the maximum THM level that the water can produce, given a long
    enough holding time. Set the bulk reaction coefficient to a positive number reflective
    of the rate of THM production (e.g., 0.7 divided by the THM doubling  time).
    Estimates of the reaction coefficient and the limiting  concentration can be obtained
    from laboratory testing.  The reaction coefficient will increase with increasing water
    temperature.  Initial concentrations at all network nodes should  at least equal the
    THM concentration entering the network from its source node.


Can I use a text editor to edit network properties while running EPANET?

    Save the network to file as ASCII text (select File » Export » Network). With
    EPANET still running, start up your text editor program. Load the saved network file
    into the  editor.  When you are  done editing the file, save it to disk. Switch to
    EPANET and read in the  file  (select File  » Open). You can keep switching back
    and forth between the editor program and EPANET, as more changes  are needed.
    Just remember to save the file after modifying it in the editor, and re-open it again
                                  133

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   after switching to EPANET. If you use a word processor (such as WordPad) or a
   spreadsheet as your editor, remember to save the file as plain ASCII text.


Can I run multiple EPANET sessions at the same time?

   Yes. This could prove useful in  making side-by-side comparisons of two or more
   different design or operating scenarios.
                                 134

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APPENDIX A - UNITS OF  MEASUREMENT
PARAMETER
Concentration
Demand
Diameter (Pipes)
Diameter (Tanks)
Efficiency
Elevation
Emitter Coefficient
Energy
Flow
Friction Factor
Hydraulic Head
Length
Minor Loss Coeff.
Power
Pressure
Reaction Coeff. (Bulk)
Reaction Coeff. (Wall)
Roughness Coefficient
Source Mass Injection
Velocity
Volume
Water Age
US CUSTOMARY
mg/L or |og/L
(see Flow units)
inches
feet
percent
feet
flow units / (psi)1/2
kilowatt - hours
CFS (cubic feet / sec)
GPM (gallons / min)
MOD (million gal / day)
IMGD (Imperial MOD)
AFD (acre-feet / day)
unitless
feet
feet
unitless
horsepower
pounds per square inch
I/day (Ist-order)
mass / L / day (0-order)
ft /day (Ist-order)
10"3 feet (Darcy-Weisbach),
unitless otherwise
mass / minute
feet / second
cubic feet
hours
SI METRIC
mg/L or |og/L
(see Flow units)
millimeters
meters
percent
meters
flow units / (meters)172
kilowatt - hours
LPS (liters / sec)
LPM (liters / min)
MLD (megaliters / day)
CMH (cubic meters / hr)
CMD (cubic meters / day)
unitless
meters
meters
unitless
kilowatts
meters
I/day (Ist-order)
mass / L / day (0-order)
meters / day (Ist-order)
millimeters (Darcy-Weisbach),
unitless otherwise
mass / minute
meters / second
cubic meters
hours
   Note:  US Customary units apply when CFS, GPM, AFD, or MOD is chosen as flow
          units. SI Metric units apply when flow units are expressed using either liters or
          cubic meters.
                                       135

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              136

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APPENDIX B  -  ERROR  MESSAGES
      ID	 Explanation
      101       An analysis was terminated due to insufficient memory available.
      110       An analysis was terminated because the network hydraulic equations could
                not be solved. Check for portions of the network not having any physical
                links back to  a tank or reservoir or for unreasonable values for network input
                data.
      200       One or more  errors were detected in the input data. The nature of the error
                will be described by the 200-series error messages listed below.
      201       There  is a syntax error in a line of the input file created from your network
                data. This is most likely to have occurred in .INP text created by a user
                outside of EPANET.
      202       An illegal numeric value was assigned to a property.
      203       An object refers to undefined node.
      204       An object refers to an undefined link.
      205       An object refers to an undefined time pattern.
      206       An object refers to an undefined curve.
      207       An attempt is made to control a check valve. Once a pipe is assigned a Check
                Valve  status with the Property Editor, its status cannot be changed by either
                simple or rule-based controls.
      208       Reference was made to an undefined node.  This could occur in a control
                statement for example.
      209       An illegal value was assigned to a node property.
      210       Reference was made to an undefined link. This could occur in a control
                statement for example.
      211       An illegal value was assigned to a link property.
      212       A source tracing analysis refers to an undefined trace node.
      213       An analysis option has an illegal value (an example would be a negative time
                step value).
      214       There  are too many characters in a line read from an input file. The lines in
                the .INP file are limited to 255 characters.
      215       Two or more nodes or links share the same  ID label.
      216       Energy data were supplied for an undefined pump.
      217       Invalid energy data were supplied for a pump.
      219       A valve is illegally connected to a reservoir or tank. A PRV, PSV or FCV
                cannot be directly connected to a reservoir or tank. Use a length of pipe to
                separate the two.
                                         137

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220        A valve is illegally connected to another valve. PRVs cannot share the same
           downstream node or be linked in series, PSVs cannot share the same
           upstream node or be linked in series, and a PSV cannot be directly connected
           to the downstream node of a PRV.
221        A rule-based control contains a misplaced clause.
223        There are not enough nodes in the network to analyze. A valid network must
           contain at least one tank/reservoir and one junction node.
224        There is not at least one tank or reservoir in the network.
225        Invalid lower/upper levels were specified for a tank (e.g., the lower lever is
           higher than the upper level).
226        No pump curve or power rating was supplied for a pump. A pump must either
           be assigned a curve  ID in its Pump Curve property or a power rating in its
           Power property. If both properties are assigned then the Pump Curve is used.
227        A pump has an invalid pump curve. A valid pump curve must have
           decreasing head with increasing flow.
230        A curve has non-increasing X-values.
233        A node is not connected to any links.
302        The system cannot open the temporary input file. Make sure that the
           EPANET Temporary Folder selected has write privileges assigned to it (see
           Section 4.9).
303        The system cannot open the status report file. See Error 302.
304        The system cannot open the binary output file. See Error 302.
308        Could not save results to file. This can occur if the disk becomes full.
309        Could not write results to report file. This can occur if the disk becomes full.
                                   138

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APPENDIX C - COMMAND  LINE  EPANET
C.1    General Instructions

          EPANET can also be run as a console application from the command line within a
          DOS window. In this case network input data are placed into a text file and results
          are written to a text file. The command line for running EPANET in this fashion is:

          epanet2d   inpfile   rptfile  outfile

          Here inpfile is the name of the input file, rptfile is the name of the output
          report file, and outfile is the name of an optional binary output file that stores
          results in a special binary format. If the latter file is not needed then just the input and
          report file names should be supplied. As written, the above command assumes that
          you are working in the  directory in which EPANET was installed or  that this
          directory has been added to the PATH statement in your AUTOEXEC.BAT file.
          Otherwise  full pathnames for the executable epanet2d.exe and the  files on the
          command line must be used. The error messages for command line EPANET are the
          same as those for Windows EPANET and are listed in Appendix B.
C.2    Input File Format

          The input file for command line EPANET has the same format as the text file that
          Windows EPANET generates from its File » Export » Network command. It is
          organized  in  sections, where each section begins with a keyword  enclosed in
          brackets. The various keywords are listed below.
Network
Components
[TITLE]
[JUNCTIONS]
[RESERVOIRS]
[TANKS]
[PIPES]
[PUMPS]
[VALVES]
[EMITTERS]
System
Operation
[CURVES]
[PATTERNS]
[ENERGY]
[STATUS]
[CONTROLS]
[RULES]
[DEMANDS]
Water
Quality
[QUALITY]
[REACTIONS]
[SOURCES]
[MIXING]
Options and
Reporting
[OPTIONS]
[TIMES]
[REPORT]
Network
Map/Tags
[COORDINATES]
[VERTICES]
[LABELS]
[BACKDROP]
[TAGS]
          The order of sections is not important. However, whenever a node or link is referred
          to in  a  section it must  have already  been defined in the  [JUNCTIONS],
          [RESERVOIRS], [TANKS], [PIPES], [PUMPS], or [VALVES] sections. Thus it is
          recommended that these sections be placed first, right after the [TITLE] section. The
          network map and tags sections are not used by command line EPANET and can be
          eliminated from the file.
                                       139

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Each section can contain one or more lines of data. Blank lines can appear anywhere
in the file and the semicolon (;) can be used to indicate that what follows on the line
is a comment, not data. A maximum of 255 characters can appear on a line. The ID
labels used to identify nodes, links, curves and patterns can be any combination of up
to 15 characters and numbers.

Figure C.I displays the input file that represents the tutorial network discussed in
Chapter 2.
    [TITLE]
    EPANET TUTORIAL

    [JUNCTIONS]
    ;ID   Elev   Demand
          0
          710
          700
          695
          700
         0
         650
         150
         200
         150
    [RESERVOIRS]
    ;ID   Head
    f
    1      700

    [TANKS]
    ;ID  Elev   InitLvl   MinLvl   MaxLvl   Diam  Volume
    7
850
         0
          15
   70
0
    [PIPES]
    ;ID  Nodel   Node2   Length   Diam  Roughness
         2
         3
         3
         4
         5
         6
        3
        6
        4
        5
        6
        7
        3000
        5000
        5000
        5000
        5000
        7000
         12
         12
         10
100
100
100
100
100
100
    [PUMPS]
    ;ID  Nodel   Node2   Parameters
    7
1
2
HEAD  1
       Figure C.I Example EPANET Input File (continued on next page)
                            140

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    [PATTERNS]
    ;ID   Multipliers
    r
    1        0.5  1.3  1  1.2
    [CURVES]
    ;ID  X-Value  Y-Value
    f
    1    1000      200

    [QUALITY]
    ;Node InitQual
    [REACTIONS]
   Global  Bulk  -1
   Global  Wall  0

    [TIMES]
   Duration            24:00
   Hydraulic Timestep 1:00
   Quality Timestep   0:05
   Pattern Timestep   6:00

    [REPORT]
   Page       55
   Energy     Yes
   Nodes      All
   Links      All

    [OPTIONS]
   Units              GPM
   Headloss           H-W
   Pattern           1
   Quality           Chlorine  mg/L
   Tolerance         0.01

    [END]
    Figure C.I Example EPANET Input File (continued from previous page)
On the pages that follow the contents and formats of each keyword section are
described in alphabetical order.
                           141

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[BACKDROP]
Purpose:
Identifies a backdrop image and dimensions for the network map.

Formats:
   DIMENSIONS      LLx   LLy   URx   URy
   UNITS             FEET/METERS/DEGREES/NONE
   FILE             filename
   OFFSET           X    Y

Definitions:
    DIMENSIONS provides the X and Y coordinates of the lower-left and upper-right corners of the map's
    bounding rectangle. Defaults are the extents of the nodal coordinates supplied in the
    [COORDINATES] section.
    UNITS specifies the units that the map's dimensions are given in. Default is NONE.
    FILE is the name of the file that contains the backdrop image.
    OFFSET lists the X and Y distance that the upper-left corner of the backdrop image is offset from the
    upper-left corner of the map's bounding rectangle. Default is zero offset.

Remarks:
a.   The [BACKDROP] section is optional and is not used at all when EPANET is run as a console
    application.
b.   Only Windows Enhanced Metafiles and bitmap files can be used as backdrops.
                                           142

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[CONTROLS]

Purpose:

Defines simple controls that modify links based on a single condition.


Format:

One line for each control which can be of the form:
     LINK linkID  status IF NODE nodelD ABOVE/BELOW value

     LINK linkID  status AT TIME time

     LINK linkID  status AT CLOCKTIME clocktime AM/PM

where:
     linkID      =  a link ID label
     status      =  OPEN or CLOSED, a pump speed setting, or a control
                    valve setting
     node ID      =  a node ID label
     value       =  a pressure for a junction or a water level for a tank
     time        =  a time since the start of the simulation in decimal
                    hours or in hours:minutes format
     clocktime  =  a 24-hour clock time (hours:minutes)


Remarks:

a.   Simple controls are used to change link status or settings based on tank water level, junction pressure,
    time into the simulation or time of day.

b.   See the notes for the [STATUS] section for conventions used in specifying link status and setting,
    particularly for control valves.


Examples:

 [CONTROLS]
 ;Close  Link 12 if  the level in Tank 23  exceeds  20  ft.
LINK 12 CLOSED IF  NODE 23 ABOVE  20

 ;0pen Link  12 if pressure  at  Node 130  is  under  30  psi
LINK 12 OPEN IF  NODE  130  BELOW 30

 ;Pump PUMP02's speed  is  set to 1.5  at  16  hours  into
 ;the simulation
LINK PUMP02 1.5  AT  TIME  16

 ;Link 12  is closed  at 10  am and  opened  at  8 pm
 ;throughout the  simulation
LINK 12 CLOSED AT  CLOCKTIME 10 AM
LINK 12 OPEN AT  CLOCKTIME  8 PM
                                       143

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[COORDINATES]
Purpose:
Assigns map coordinates to network nodes.

Format:
One line for each node containing:
    •   Node ID label
    •   X-coordinate
    •   Y-coordinate

Remarks:
a.   Include one line for each node displayed on the map.
b.   The coordinates represent the distance from the node to an arbitrary origin at the lower left of the map.
    Any convenient units of measure for this distance can be used.
c.   There is no requirement that all nodes be included in the map, and their locations need not be to actual
    scale.
d.   A [COORDINATES] section is optional and is not used at all when EPANET is run as a console
    application.

Example:
[COORDINATES]
;Node         X-Coord.      Y-Coord
   1           10023         128
   2           10056         95
                                           144

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[CURVES]

Purpose:

Defines data curves and their X,Y points.


Format:

One line for each X,Y point on each curve containing:

    •   Curve ID label

    •   X value

    •   Y value


Remarks:

a.   Curves can be used to represent the following relations:
    •   Head v. Flow for pumps
    •   Efficiency v. Flow for pumps
    •   Volume v. Depth for tanks
    •   Headless v. Flow for General Purpose Valves

b.   The points of a curve must be entered in order of increasing X-values (lower to higher).

c.   If the input file will be  used with the Windows version of EPANET, then adding a comment which
    contains the curve type and description, separated by a colon, directly above the first entry for a curve
    will ensure that these items appear correctly in EPANET's Curve Editor. Curve types include PUMP,
    EFFICIENCY, VOLUME, and HEADLOSS. See the examples below.


Example:
 [CURVES]
 ;ID    Flow     Head
 ;PUMP:  Curve for  Pump 1
Cl      0         200
Cl      1000     100
Cl      3000     0

 ;ID    Flow     Effic.
 /EFFICIENCY:
El      200      50
El      1000     85
El      2000     75
El      3000     65
                                          145

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[DEMANDS]
Purpose:
Supplement to [JUNCTIONS] section for defining multiple water demands at junction nodes.

Format:
One line for each category of demand at a junction containing:
    •   Junction ID label
    •   Base demand (flow units)
    •   Demand pattern ID (optional)
    •   Name of demand category preceded by a semicolon (optional)

Remarks:
a.   Only use for junctions whose demands need to be changed or supplemented from entries in
    [JUNCTIONS] section.
b.   Data in this section replaces any demand entered in [JUNCTIONS] section for the same junction.
c.   Unlimited number of demand categories can be entered per junction.
a.   If no demand pattern is supplied then the junction demand follows the Default Demand Pattern
    specified in the [OPTIONS] section or Pattern 1 if no default pattern is specified. If the default pattern
    (or Pattern 1) does not exist, then the demand remains constant.

Example:

 [DEMANDS]
 ;ID     Demand    Pattern     Category
Jl       100         101      /Domestic
Jl       25          102      ;School
J256    50          101      /Domestic
                                          146

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[EMITTERS]
Purpose:
Defines junctions modeled as emitters (sprinklers or orifices).

Format:
One line for each emitter containing:
    •   Junction ID label
    •   Flow coefficient, flow units at 1 psi (1 meter) pressure drop

Remarks:
a.   Emitters are used to model flow through sprinkler heads or pipe leaks.
b.   Flow out of the emitter equals the product of the flow coefficient and the junction pressure raised to a
    power.
c.   The power can be specified using the EMITTER EXPONENT option in the [OPTIONS] section. The
    default power is 0.5, which normally applies to sprinklers and nozzles.
d.   Actual demand reported in the program's results includes both the normal demand at the junction plus
    flow through the emitter.
e.   An [EMITTERS] section is optional.
                                            147

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[ENERGY]
Purpose:
Defines parameters used to compute pumping energy and cost.

Formats:
   GLOBAL           PRICE/PATTERN/EFFIC   value
   PUMP    PumpID   PRICE/PATTERN/EFFIC   value
   DEMAND CHARGE   value

Remarks:
c.   Lines beginning with the keyword GLOBAL are used to set global default values of energy price, price
    pattern, and pumping efficiency for all pumps.
d.   Lines beginning with the keyword PUMP are used to override global defaults for specific pumps.
e.   Parameters are defined as follows:
    •   PRICE = average cost per kW-hour,
    •   PATTERN = ID label of time pattern describing how energy price varies with time,
    •   EFFIC = either a single percent efficiency for global setting or the ID label of an efficiency curve
       for a specific pump,
    •   DEMAND CHARGE = added cost per maximum kW usage during the simulation period.
f   The default global pump efficiency is 75% and the default global energy price is 0.
g.   All entries in this section are optional. Items offset by slashes (/) indicate allowable choices.

Example:

 [ENERGY]
GLOBAL PRICE        0.05    ;Sets  global  energy price
GLOBAL PATTERN     PAT1    ;and  time-of-day pattern
PUMP   23  PRICE   0.10    ;Overrides price for  Pump 23
PUMP   23  EFFIC   E23     ;Assigns effic.  curve to Pump 23
                                         148

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[JUNCTIONS]

Purpose:

Defines junction nodes contained in the network.


Format:

One line for each junction containing:

    •   ID label

    •   Elevation, ft (m)

    •   Base demand flow (flow units) (optional)

    •   Demand pattern ID (optional)


Remarks:

b.   A [JUNCTIONS] section with at least one junction is required.

c.   If no demand pattern is supplied then the junction demand follows the Default Demand Pattern
    specified in the [OPTIONS] section or Pattern 1 if no default pattern is specified. If the default pattern
    (or Pattern 1) does not exist, then the  demand remains constant.

d.   Demands can also be entered in the [DEMANDS] section and include multiple demand categories per
   junction.


Example:

 [JUNCTIONS]
 ;ID     Elev.     Demand    Pattern
Jl      100        50         Patl
J2      120        10                 ;Uses default demand  pattern
J3      115                           ;No demand  at this  junction
                                          149

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[LABELS]
Purpose:
Assigns coordinates to map labels.

Format:
One line for each label containing:
    •   X-coordinate
    •   Y-coordinate
    •   Text of label in double quotes
    •   ID label of an anchor node (optional)

Remarks:
a.   Include one line for each label on the map.
b.   The coordinates refer to the upper left corner of the label and are with respect to an arbitrary origin at
    the lower left of the map.
c.   The optional anchor node anchors the label to the node when the map is re-scaled during zoom-in
    operations.
d.   The [LABELS] section is optional and is not used at all when EPANET is run as a console application.
Example:
 [LABELS]
 ;X-Coord.
Y-Coord.
Label
Anchor
   1230
   34.57
3459
12.75
"Pump  1"
"North  Tank'
T22
                                           150

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[MIXING]

Purpose:
Identifies the model that governs mixing within storage tanks.


Format:
One line per tank containing:

    •   Tank ID label

    •   Mixing model (MIXED, 2COMP, FIFO, or LIFO)

    •   Compartment volume (fraction)


Remarks:
a.   Mixing models include:
    •   Completely Mixed (MIXED)
    •   Two-Compartment Mixing (2COMP)
    •   Plug Flow (FIFO)
    •   Stacked Plug Flow (LIFO)

b.   The compartment volume parameter only applies to the two-compartment model and represents the
    fraction of the total tank volume devoted to the inlet/outlet compartment.
c.   The [MIXING] section is optional. Tanks not described in this section are assumed to be completely
    mixed.


Example:

 [MIXING]
 ;Tank       Model
T12          LIFO
T23          2COMP      0.2
                                          151

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[OPTIONS]
Purpose:
Defines various simulation options.
Formats:
   UNITS

   HEADLOSS
   HYDRAULICS
   QUALITY
   VISCOSITY
   DIFFUSIVITY
   SPECIFIC GRAVITY
   TRIALS
   ACCURACY
   UNBALANCED
   PATTERN
   DEMAND MULTIPLIER
   EMITTER EXPONENT
   TOLERANCE
   MAP
CFS/GPM/MGD/IMGD/AFD/
LPS/LPM/MLD/CMH/CMD
H-W/D-W/C-M
USE / SAVE   filename
NONE/CHEMICAL/AGE/TRACE  id
value
value
value
value
value
STOP/CONTINUE/CONTINUE n
id
value
value
value
filename
Definitions:
    UNITS sets the units in which flow rates are expressed where:
       CFS      =  cubic feet per second
       GPM      =  gallons per minute
       MGD      =  million gallons per day
       IMGD    =  Imperial MGD
       AFD      =  acre-feet per day
       LPS      =  liters per second
       LPM      =  liters per minute
       MLD      =  million liters per day
       CMH      =  cubic meters per hour
       CMD      =  cubic meters per day
    For CFS,  GPM,  MGD,  IMGD, and AFD other input quantities are expressed in US Customary Units.
    If flow units are in liters or cubic meters then Metric Units must be used for all other input quantities as
                                         152

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well. (See Appendix A. Units of Measurement). The default flow units are GPM.

HEAD LOSS selects a formula to use for computing head loss for flow through a pipe. The choices are
the Hazen-Williams (H-W), Darcy-Weisbach (D-W), or Chezy-Manning (C-M) formulas. The default is
H-W.

The HYDRAULICS option allows you to either SAVE the current hydraulics solution to a file or USE a
previously saved hydraulics solution. This is useful when studying factors that only affect water
quality behavior.

QUALITY selects the type of water quality analysis to perform. The choices are NONE, CHEMICAL,
AGE, and TRACE. In place of CHEMICAL the actual name of the chemical can be used followed by its
concentration units  (e.g., CHLORINE mg/L). If TRACE is selected it must be followed by the ID label
of the node being traced. The default selection is NONE (no water quality analysis).

VISCOSITY is the kinematic viscosity of the fluid being modeled relative to that of water at 20 deg. C
(1.0 centistoke). The default value is 1.0.

DIFFUSIVITY is the molecular diffusivity of the chemical being analyzed relative to that of chlorine
in water. The default value is 1.0. Diffusivity is only used when mass transfer limitations are
considered in pipe wall reactions. A value of 0 will cause EPANET to ignore mass transfer limitations.

SPECIFIC  GRAVITY is the ratio of the density of the fluid being modeled to that of water at 4 deg.
C (unitless).

TRIALS are the maximum number of trials used to  solve network hydraulics at each hydraulic time
step of a simulation. The default is 40.

ACCURACY prescribes the convergence criterion that determines when a hydraulic solution has been
reached. The trials end when the sum of all flow changes from the previous solution divided by the
total flow in all links is less than this number.  The default is 0.001.

UNBALANCED determines what happens if a hydraulic solution cannot be reached within the
prescribed number of TRIALS at some hydraulic time step into the simulation. "STOP" will halt the
entire analysis at that point. "CONTINUE" will continue the analysis with a warning message issued.
"CONTINUE n" will continue the search for a solution for another "n" trials with the status of all
links held fixed at their current settings. The simulation will be continued at this point with a message
issued about whether convergence was achieved or not. The default choice is "STOP".

PATTERN provides the ID label of a default demand pattern to be applied to all junctions where no
demand pattern was specified. If no such pattern exists in the [PATTERNS] section then by default the
pattern consists of a single multiplier equal to  1.0. If this option is not used, then the global default
demand pattern has a label of "1".

The DEMAND MULTIPLIER is used to adjust the values of baseline demands for all junctions and all
demand categories.  For example, a value of 2  doubles all baseline demands, while a value of 0.5 would
halve them. The default value is 1.0.

EMITTER EXPONENT specifies the power to which the pressure at a junction is raised when
computing the flow issuing from an emitter. The default is 0.5.

MAP is used to supply the name of a file containing coordinates of the network's nodes so that a map of
the network can be drawn. It is not used for any hydraulic or water quality computations.
                                         153

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    TOLERANCE is the difference in water quality level below which one can say that one parcel of water
    is essentially the same as another. The default is 0.01 for all types of quality analyses (chemical, age
    (measured in hours), or source tracing (measured in percent)).
Remarks:

a.   All options assume their default values if not explicitly specified in this section.

b.   Items offset by slashes (/) indicate allowable choices.


Example:


 [OPTIONS]
UNITS         CFS
HEADLOSS      D-W
QUALITY       TRACE   Tank23
UNBALANCED   CONTINUE   10
                                            154

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[PATTERNS]

Purpose:

Defines time patterns.


Format:

One or more lines for each pattern containing:

    •  Pattern ID label

    •  One or more multipliers


Remarks:

a.   Multipliers define how some base quantity (e.g., demand) is adjusted for each time period.

a.   All patterns share the same time period interval as defined in the [TIMES] section.

b.   Each pattern can have a different number of time periods.

c.   When the simulation time exceeds the pattern length the pattern wraps around to its first period.

d.   Use as many lines as it takes to include all multipliers for each pattern.


Example:

 [PATTERNS]
 ;Pattern  PI
PI      1.1     1.4    0.9     0.7
PI      0.6     0.5    0.8     1.0
 ;Pattern  P2
P2      1       1       1       1
P2      0       0       1
                                           155

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[PIPES]
Purpose:
Defines all pipe links contained in the network.

Format:
One line for each pipe containing:
    •    ID label of pipe
    •    ID of start node
    •    ID of end node
    •    Length, ft (m)
    •    Diameter, inches (mm)
    •    Roughness coefficient
    •    Minor loss coefficient
    •    Status (OPEN, CLOSED, or CV)

Remarks:
a.   Roughness coefficient is unitless for the Hazen-Williams and Chezy-Manning head loss formulas and
    has units of millifeet (mm) for the Darcy-Weisbach formula. Choice of head loss formula is supplied in
    the [OPTIONS] section.
b.   Setting status to CV means that the pipe contains a check valve restricting flow to one
    direction.
c.   If minor loss coefficient is 0 and pipe is OPEN then these two items can be dropped form the
    input line.

Example:

 [PIPES]
 ;ID    Nodel   Node2    Length    Diam.   Roughness   Mloss     Status
PI
P2
P3
Jl
J3
Jl
J2
J2
J10
1200
600
1000
12
6
12
120
110
120
0.2
0

OPEN
CV

                                          156

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[PUMPS]
Purpose:
Defines all pump links contained in the network.

Format:
One line for each pump containing:
    •   ID label of pump
    •   ID of start node
    •   ID of end node
    •   Keyword and Value (can be repeated)

Remarks:
a.   Keywords consists of:
    •   POWER - power value for constant energy pump, hp (kW)
    •   HEAD - ID of curve that describes head versus flow for the pump
    •   SPEED - relative speed setting (normal speed is 1.0, 0 means pump is off)
    •   PATTERN - ID of time pattern that describes how speed setting varies with time
b.   Either POWER or HEAD must be supplied for each pump. The other keywords are optional.

Example:

 [PUMPS]
 ;ID     Nodel     Node2    Properties
 i
Pumpl    N12      N32      HEAD  Curvel
Pump2    N121     N55      HEAD  Curvel  SPEED 1.2
PumpS    N22      N23      POWER 100
                                         157

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[QUALITY]
Purpose:
Defines initial water quality at nodes.

Format:
One line per node containing:
    •   Node ID label
    •   Initial quality

Remarks:
a.   Quality is assumed to be zero for nodes not listed.
b.   Quality represents concentration for chemicals, hours for water age, or percent for source tracing.
c.   The [QUALITY] section is optional.
                                             158

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[REACTIONS]
Purpose:
Defines parameters related to chemical reactions occurring in the network.

Formats:
   ORDER  BULK/WALL/TANK  value
   GLOBAL BULK/WALL       value
   BULK/WALL/TANK          pipelD value
   LIMITING  POTENTIAL     value
   ROUGHNESS CORRELATION value

Definitions:
    ORDER is used to set the order of reactions occurring in the bulk fluid, at the pipe wall, or in tanks,
    respectively. Values for wall reactions must be either 0 or 1. If not supplied the default reaction order
    is 1.0.
    GLOBAL is used to set a global value for all bulk reaction coefficients (pipes and tanks) or for all pipe
    wall coefficients. The default value is zero.
    BULK,  WALL, and TANK are used to override the global reaction coefficients for specific pipes and
    tanks.
    LIMITING POTENTIAL specifies that reaction rates are proportional to the difference between the
    current concentration and some limiting potential value.
    ROUGHNESS CORRELATION will make all default pipe wall reaction coefficients be related to pipe
    roughness in the following manner:
            Head Loss Equation        Roughness Correlation
            Hazen-Williams           F / C
            Darcy-Weisbach           F / log(e/D)
            Chezy-Manning           F*n
    where F = roughness correlation, C = Hazen-Williams C-factor, e = Darcy-Weisbach roughness, D =
    pipe diameter, and n = Chezy-Manning roughness coefficient. The default value computed this way
    can be overridden for any pipe by using the WALL format to supply a specific value for the pipe.

Remarks:
a.   Remember to use positive numbers for growth reaction coefficients and negative numbers for decay
    coefficients.
b.   The time units for all reaction coefficients are I/days.
c.   All entries in this section are optional. Items offset by slashes (/) indicate allowable  choices.
                                             159

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Example:

 [REACTIONS]
ORDER WALL    0     ;Wall reactions  are  zero-order
GLOBAL BULK  -0.5   ;Global bulk decay coeff.
GLOBAL WALL  -1.0   ;Global wall decay coeff.
WALL   P220  -0.5   ;Pipe-specific wall  coeffs.
WALL   P244  -0.7
                                   160

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[REPORT]

Purpose:
Describes the contents of the output report produced from a simulation.


Formats:
   PAGE SIZE         value

   FILE              filename
   STATUS            YES/NO/FULL
   SUMMARY           YES/NO
   ENERGY            YES/NO

   NODES             NONE/ALL/nodel node2 ...

   LINKS             NONE/ALL/linkl Iink2 ...
   parameter        YES/NO

   parameter        BELOW/ABOVE/PRECISION    value


Definitions:

    PAGE s IZE sets the number of lines written per page of the output report. The default is 0, meaning
    that no line limit per page is in effect.

    FILE supplies the name of a file to which the output report will be written (ignored by the Windows
    version of EPANET).

    STATUS determines whether a hydraulic status report should be generated. If YES is selected the
    report will identify all network components that change status during each time step of the simulation.
    If FULL is selected, then the status report will also include information from each trial of each
    hydraulic  analysis. This level of detail is only useful for de-bugging networks that become
    hydraulically unbalanced. The default is NO.

    SUMMARY determines whether a summary table of number of network components and key analysis
    options is generated. The default is YES.

    ENERGY determines if a table reporting average energy usage and cost for each pump is provided. The
    default is NO.

    NODES identifies which nodes will be reported on. You can either list individual node ID labels or use
    the keywords NONE or ALL. Additional NODES lines can be used to continue the list. The default is
    NONE.

    LINKS identifies which links will be reported on. You can either list individual link ID labels or use
    the keywords NONE or ALL. Additional LINKS lines can be used to continue the list. The default is
    NONE.

    The "parameter" reporting option is used to identify which quantities are reported on, how many
    decimal places are displayed, and what kind of filtering should be used to limit output reporting. Node
    parameters that can be reported on include:
                                            161

-------
    •  Elevation

    •  Demand

    •  Head

    •  Pressure

    •  Quality.

    Link parameters include:

    •  Length

    •  Diameter

    •  Flow

    •  Velocity

    •  Headloss

    •  Position (same as status - open, active, closed)

    •  Setting (Roughness for pipes, speed for pumps, pressure/flow setting for valves)

    •  Reaction (reaction rate)

    •  F-Factor (friction factor).

    The default quantities reported are Demand,  Head,  Pressure, and Quality for nodes and
    Flow,  Velocity, and Headloss for links. The default precision is two decimal places.


Remarks:

a.   All options assume their default values if not explicitly specified in this section.

b.   Items offset by slashes (/) indicate allowable choices.

c.   The default is to not report on any nodes or links, so a NODES or LINKS option must be supplied if
    you wish to report results for these items.

d.   For the Windows version of EPANET, the only [REPORT] option recognized is STATUS. All others
    are ignored.


Example:

The following example reports on nodes Nl, N2, N3, and N17 and all links with velocity above 3.0. The
standard node parameters (Demand, Head, Pressure, and Quality) are reported on while only Flow,
Velocity, and F-Factor (friction factor) are displayed for links.


 [REPORT]
NODES Nl N2 N3 N17
LINKS ALL
FLOW YES
VELOCITY PRECISION  4
F-FACTOR PRECISION  4
VELOCITY ABOVE 3.0
                                          162

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[RESERVOIRS]
Purpose:
Defines all reservoir nodes contained in the network.

Format:
One line for each reservoir containing:
    •    ID label
    •    Head, ft (m)
    •    Head pattern ID (optional)

Remarks:
a.   Head is the hydraulic head (elevation + pressure head) of water in the reservoir.
b.   A head pattern can be used to make the reservoir head vary with time.
c.   At least one reservoir or tank must be contained in the network.

Example:

 [RESERVOIRS]
 ;ID     Head     Pattern
 Rl     512                  ;Head  stays  constant
 R2     120      Patl       ;Head  varies  with time
                                          163

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[RULES]
Purpose:
Defines rule-based controls that modify links based on a combination of conditions.

Format:
Each rule is a series of statements of the form:
  RULE rulelD
  IF  condition  1
  AND condition  2
  OR  condition  3
  AND condition  4
  etc.
  THEN action_l
  AND  action_2
  etc.
  ELSE action_3
  AND  action_4
  etc.
  PRIORITY value
where:
   rulelD
   conditon n
   action_n
   Priority
=  an ID label assigned to the rule
=  a condition clause
=  an action clause
=  a priority value (e.g., a number from 1 to 5)
Condition Clause Format:

A condition clause in a Rule-Based Control takes the form of:
    object  id attribute  relation value
where
object =
id
attribute =
relation =
value =
a category of network object
the object's ID label
an attribute or property of the object
a relational operator
an attribute value
Some example conditional clauses are:
                                        164

-------
       JUNCTION 23  PRESSURE  > 20
       TANK T200 FILLTIME BELOW 3.5
       LINK 44  STATUS IS OPEN
       SYSTEM  DEMAND >=  1500
       SYSTEM  CLOCKTIME  = 7:30 AM
The Object keyword can be any of the following:
       NODE          LINK          SYSTEM
       JUNCTION     PIPE
       RESERVOIR    PUMP
       TANK          VALVE

When SYSTEM is used in a condition no ID is supplied.

The following attributes can be used with Node-type objects:
       DEMAND
       HEAD
       PRESSURE
The following attributes can be used with Tanks:
       LEVEL
       FILLTIME (hours needed to fill a tank)
       DRAINTIME (hours needed to empty a tank)

These attributes can be used with Link-Type objects:
       FLOW
       STATUS  (OPEN, CLOSED,or ACTIVE)
       SETTING (pump speed or valve setting)

The SYSTEM object can use the following attributes:
       DEMAND (total system demand)
       TIME (hours from the start of the simulation expressed either as a decimal number or in
       hours:minutes format)
       CLOCKTIME (24-hour clock time with AM or PM appended)
                                         165

-------
Relation operators consist of the following:
               IS
        <>     NOT
        <      BELOW
        >      ABOVE
        <=     >=
Action Clause Format:
An action clause in a Rule-Based Control takes the form of:
        object id STATUS/SETTING  IS  value
where
        ob j ect    =   LINK, PIPE, PUMP, or VALVE keyword
        id         =   the object's ID label
        value     =   a status condition (OPEN or CLOSED), pump speed setting, or valve
                       setting
Some example action clauses are:
        LINK  23  STATUS  IS  CLOSED
        PUMP  P100 SETTING  IS  1.5
        VALVE 123 SETTING  IS  90

Remarks:
a.   Only the RULE,  IF and THEN portions of a rule are required; the other portions are optional.
b.   When mixing AND and OR clauses, the OR operator has higher precedence than AND, i.e.,
        IF A  or  B and C
    is equivalent to
        IF  (A or  B)  and C.
    If the interpretation was meant to be
        IF A  or  (B and  C)
    then this can be expressed using two rules as in
        IF A  THEN . . .
        IF B  and  C THEN . . .
c.   The PRIORITY value is used to determine which rule applies when two or more rules require that
    conflicting actions be taken on a link.  A rule without a priority value always has a lower priority than
    one with a value. For two rules with the same priority value, the rule that appears first is given the
    higher priority.
                                           166

-------
Example:

 [RULES]
RULE 1
IF   TANK    1  LEVEL  ABOVE 19.1
THEN PUMP 335  STATUS IS  CLOSED
AND  PIPE 330  STATUS IS  OPEN

RULE 2
IF   SYSTEM  CLOCKTIME >= 8 AM
AND  SYSTEM  CLOCKTIME <  6 PM
AND  TANK 1  LEVEL  BELOW  12
THEN PUMP 335  STATUS IS  OPEN

RULE 3
IF   SYSTEM  CLOCKTIME >= 6 PM
OR   SYSTEM  CLOCKTIME <  8 AM
AND  TANK 1  LEVEL  BELOW  14
THEN PUMP 335  STATUS IS  OPEN
                                   167

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[SOURCES]
Purpose:
Defines locations of water quality sources.

Format:
One line for each water quality source containing:
    •   Node ID label
    •   Source type (CONCEN,  MASS,  FLOWPACED, or SETPOINT)
    •   Baseline source strength
    •   Time pattern ID (optional)

Remarks:
a.   For MASS type sources, strength is measured in mass flow per minute. All other types measure source
    strength in concentration units.
b.   Source strength can be made to vary over time by specifying a time pattern.
c.   A CONCEN source:
    •   represents the concentration of any external source inflow to the node
    •   applies only when the node has a net negative demand (water enters the network at the node)
    •   if the node is a junction, reported concentration is the result of mixing the source flow and inflow
        from the rest of the network
    •   if the node is a reservoir, the reported concentration is the source concentration
    •   if the node is a tank, the reported concentration is the internal concentration of the tank
    •   is best used for nodes that represent source water supplies or treatment works (e.g., reservoirs or
        nodes assigned a negative demand)
    •   should  not be used at storage tanks with simultaneous inflow/outflow.
d.   A MASS,  FLOWPACED, or SETPOINT source:
    •   represents a booster source, where the substance is injected directly into the network irregardless
        of what the demand at the node is
    •   affects  water leaving the node to the rest of the network in the following way:
            a MASS booster adds a fixed mass flow to that resulting from inflow to the node
            a FLOWPACED booster adds a fixed concentration to the resultant inflow concentration at the
            node
            a SETPOINT booster fixes the concentration of any flow leaving the node (as long as the
            concentration resulting from the inflows is below the setpoint)
    •   the reported concentration at a junction or reservoir booster source is the concentration that results
        after the boosting is applied; the reported concentration for a tank with a booster source is the
        internal concentration of the tank
                                              168

-------
    •   is best used to model direct injection of a tracer or disinfectant into the network or to model a
       contaminant intrusion.
e.   A [SOURCES] section is not needed for simulating water age or source tracing.
Example:

 [SOURCES]
 ;Node  Type     Strength  Pattern
 f
  Nl    CONCEN     1.2       Patl     ;Concentration varies  with  time
  N44  MASS       12                  /Constant mass injection
                                        169

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[STATUS]
Purpose:
Defines initial status of selected links at the start of a simulation.

Format:
One line per link being controlled containing:
    •   Link ID label
    •   Status or setting

Remarks:
a.   Links not listed in this section have a default status of OPEN (for pipes and pumps) or ACTIVE (for
    valves).
b.   The status value can be OPEN or CLOSED. For control valves (e.g., PRVs, FCVs, etc.) this means that
    the valve is either fully opened or closed, not active at its control setting.
c.   The setting value can be a speed setting for pumps or valve setting for valves.
d.   The initial status of pipes can also be set in the [PIPES] section.
e.   Check valves cannot have their status be preset.
f.   Use [CONTROLS] or [RULES] to change status or setting at some future point in the simulation.
g.   If a CLOSED or OPEN control valve is to become ACTIVE again, then its pressure or flow setting must
    be specified in the control or rule that re-activates it.

Example:
[STATUS]
;  Link   Status/Setting
    L22      CLOSED         ;Link L22 is  closed
    P14      1.5             ;Speed  for pump  P14
    PRV1    OPEN            ;PRV1 forced  open
                             ;(overrides normal operation)
                                           170

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[TAGS]

Purpose:
Associates category labels (tags) with specific nodes and links.


Format:
One line for each node and link with a tag containing
    •   the keyword NODE or LINK
    •   the node or link ID label
    •   the text of the tag label (with no spaces)


Remarks:
a.   Tags can be useful for assigning nodes to different pressure zones or for classifying pipes by material
    or age.
b.   If a node or link's  tag is not identified in this section then it is assumed to be blank.
c.   The [TAGS] section is optional and has no effect on the hydraulic or water quality calculations.
Example:

 [TAGS]
 ;0bject   ID
           Tag
 NODE
 NODE
 NODE
 LINK
 LINK
1001
1002
  45
 201
 202
Zone_A
Zone_A
Zone_B
UNCI-1960
PVC-1985
                                           171

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[TANKS]

Purpose:

Defines all tank nodes contained in the network.


Format:

One line for each tank containing:

    •   ID label

    •   Bottom elevation, ft (m)

    •   Initial water level, ft (m)

    •   Minimum water level, ft (m)

    •   Maximum water level, ft (m)

    •   Nominal diameter, ft (m)

    •   Minimum volume, cubic ft (cubic meters)

    •   Volume curve ID (optional)


Remarks:

a.   Water surface elevation equals bottom elevation plus water level.

b.   Non-cylindrical tanks can be modeled by specifying a curve of volume versus water depth in the
    [CURVES] section.

c.   If a volume curve is supplied the diameter value can be any non-zero number

d.   Minimum volume (tank volume at minimum water level) can be zero for a cylindrical tank or if a
    volume curve is supplied.

e.   A network must contain at least one tank or reservoir.


Example:

 [TANKS]
 ;ID    Elev.   InitLvl   MinLvl   MaxLvl  Diam  MinVol  VolCurve
 r
 /Cylindrical  tank
Tl      100      15         5         25      120    0
 /Non-cylindrical  tank with  arbitrary diameter
T2    100      15         5         25      1       0          VC1
                                          172

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[TIMES]
Purpose:
Defines various time step parameters used in the simulation.

Formats:
    DURATION                Value (units)
    HYDRAULIC  TIMESTEP   Value (units)
    QUALITY TIMESTEP      Value (units)
    RULE TIMESTEP          Value (units)
    PATTERN TIMESTEP      Value (units)
    PATTERN START          Value (units)
    REPORT  TIMESTEP       Value (units)
    REPORT  START           Value (units)
    START CLOCKTIME       Value (AM/PM)
    STATISTIC               NONE/AVERAGED/
                              MINIMUM/MAXIMUM
                              RANGE
Definitions:
    DURATION is the duration of the simulation. Use 0 to run a single period snapshot analysis. The
    default is 0.
    HYDRAULIC TIMESTEP determines how often a new hydraulic state of the network is computed. If
    greater than either the PATTERN or REPORT time step it will be automatically reduced. The default is
    1 hour.
    QUALITY TIMESTEP is the time step used to track changes in water quality throughout the network.
    The default is 1/10 of the hydraulic time step.
    RULE TIMESTEP is the time step used to check for changes in system status due to activation of
    rule-based controls between hydraulic time steps. The default is 1/10 of the hydraulic time step.
    PATTERN TIMESTEP is the interval between time periods in all time patterns. The default is 1 hour.
    PATTERN START is the time offset at which all patterns will start. For example, a value of 6 hours
    would start the simulation with each pattern in the time period that corresponds to hour 6. The default
    isO.
    REPORT  TIMESTEP sets the time interval between which output results are reported. The default is 1
    hour.
    REPORT  START is the length of time into the simulation at which output results begin to be reported.
    The default is 0.
    START CLOCKTIME is the time of day (e.g., 3:00 PM) at which the simulation begins. The default is
    12:00 AM midnight.
                                           173

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    STATISTIC determines what kind of statistical post-processing should be done on the time series of
    simulation results generated. AVERAGED reports a set of time-averaged results, MINIMUM reports only
    the minimum values, MAXIMUM the maximum values, and RANGE reports the difference between the
    minimum and maximum values. NONE reports the full time series for all quantities for all nodes and
    links and is the default.
Remarks:

a.   Units can be SECONDS  (SEC), MINUTES  (MIN) , HOURS, or DAYS. The default is hours.

b.   If units are not supplied, then time values can be entered as decimal hours or in hours:minutes notation.

c.   All entries in the [TIMES] section are optional. Items offset by slashes (/) indicate allowable choices.


Example:


 [TIMES]
DURATION             240  HOURS
QUALITY TIMESTEP   3 MIN
REPORT  START        120
STATISTIC            AVERAGED
START  CLOCKTIME    6:00 AM
                                           174

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[TITLE]
Purpose:
Attaches a descriptive title to the network being analyzed.

Format:
Any number of lines of text.

Remarks:
The [TITLE] section is optional.
                                           175

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[VALVES]
Purpose:
Defines all control valve links contained in the network.

Format:
One line for each valve containing:
    •   ID label of valve
    •   ID of start node
    •   ID of end node
    •   Diameter, inches (mm)
    •   Valve type
    •   Valve setting
    •   Minor loss coefficient
Remarks:
a.   Valve types and settings include:
    Valve Type	
    PRV (pressure reducing valve)
    PSV (pressure sustaining valve)
    PB V (pressure breaker valve)
    FCV (flow control valve)
    TCV (throttle control valve)
    GPV (general purpose valve)
Setting
Pressure, psi (m)
Pressure, psi (m)
Pressure, psi (m)
Flow (flow units)
Loss Coefficient
ID of head loss curve
b.  Shutoff valves and check valves are considered to be part of a pipe, not a separate control valve
    component (see [PIPES])
                                             176

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[VERTICES]
Purpose:
Assigns interior vertex points to network links.

Format:
One line for each point in each link containing such points that includes:
    •   Link ID label
    •   X-coordinate
    •   Y-coordinate

Remarks:
a.   Vertex points allow links to be drawn as polylines instead of simple straight-lines between their end
    nodes.
b.   The coordinates refer to the same coordinate system used for node and label coordinates.
c.   A [VERTICES] section is optional and is not used at all when EPANET is run as a console
    application.

Example:
[COORDINATES]
;Node         X-Coord.      Y-Coord
   1           10023         128
   2           10056         95
                                           177

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C.3    Report File Format
           Statements supplied to the [REPORT] section of the input file control the contents of
           the report file generated from a command-line run of EPANET. A portion of the
           report generated from the input file of Figure C.I is shown in Figure C.2. In general a
           report can contain the following sections:

              •   Status Section

              •   Energy Section

              •   Nodes Section

              •   Links Section


           Status Section

           The Status Section  of the output report lists the initial status of all reservoirs, tanks,
           pumps, valves,  and closed pipes  as well  as  any  changes in the  status of these
           components as they occur over time in  an extended period simulation. The status of
           reservoirs and tanks indicates whether they are filling or emptying. The status of
           links indicates whether they are open or closed and includes the relative speed setting
           for pumps and  the pressure/flow  setting for  control  valves. To include a Status
           Section in the report use the command STATUS YES in the [REPORT] section of
           the input  file.

           Using STATUS FULL will also produce  a full listing of the convergence results for
           all iterations of each hydraulic analysis made during a simulation. This listing will
           also show which components are changing status during the iterations. This level of
           detail is only useful when one is trying to debug a run that fails to converge because a
           component's status  is cycling.


           Energy Section

           The Energy Section of the output report lists overall energy consumption and cost for
           each pump in the network. The items listed for each pump include:

              •   Percent Utilization (percent of the time that the pump is on-line)

              •   Average Efficiency

              •   Kilowatt-hours  consumed  per million gallons  (or  cubic  meters)
                  pumped

              •   Average Kilowatts consumed

              •   Peak Kilowatts used

              •   Average cost per day

           Also listed is the total cost per day for pumping and the total demand charge (cost
           based on  the peak energy usage) incurred. To include an Energy Section in the report
           the command ENERGY YES must appear in the [REPORT] section of the input file.
                                         178

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 *                            EPANET                          *
 *                    Hydraulic and Water Quality                  *
 *                    Analysis for Pipe Networks                   *
 *                            Version 2.0                          *
 ******************************************************************

 EPANET  TUTORIAL

     Input  Data File 	 tutorial. inp
     Number of Junctions	 5
     Number of Reservoirs	 1
     Number of Tanks 	 1
     Number of Pipes 	 6
     Number of Pumps 	 1
     Number of Valves 	 0
     Headloss  Formula 	 Hazen-Williams
     Hydraulic Timestep 	 1.00 hrs
     Hydraulic Accuracy 	 0.001000
     Maximum Trials  	 40
     Quality Analysis 	 Chlorine
     Water  Quality Time Step 	 5.00 min
     Water  Quality Tolerance 	 0.01 mg/L
     Specific  Gravity 	 1.00
     Relative  Kinematic Viscosity 	 1.00
     Relative  Chemical Diffusivity 	 1.00
     Demand Multiplier 	 1.00
     Total  Duration  	 24.00 hrs
     Reporting Criteria:
        All Nodes
        All Links

 Energy  Usage:

            Usage    Avg.     Kw-hr      Avg.       Peak      Cost
 Pump      Factor  Effic.     /Mgal        Kw        Kw      /day

 7          100.00   75.00    746.34     51.34      51.59      0.00

                                        Demand Charge:      0.00
	Total Cost:	0. 00

         Figure C.2 Excerpt from a Report File (continued on next page)
                                179

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Node Results at 0

Node
2
3
4
5
6
1
7
Link Results at

Link
1
2
3
4
5
6
7
Node Results at

Node
2
3
4
5
6
1
7
Link Results at

Link
1
2
3
4
5
6
7
:00 hrs :
Demand
gpm
0.00
325.00
75.00
100.00
75.00
-1048.52
473.52
0: 00 hrs :
Flow
gpm
1048.52
558.33
165.19
90.19
-9.81
473.52
1048.52
1:00 hrs:
Demand
gpm
0.00
325.00
75.00
100.00
75.00
-1044.60
469.60
1:00 hrs:
Flow
gpm
1044.60
555.14
164.45
89.45
-10.55
469.60
1044.60

Head
ft
893.37
879.78
874.43
872.69
872.71
700.00
855.00

Velocity
fps
2.97
1.58
1.05
0.58
0.06
1.93
0.00

Head
ft
893.92
880.42
875.12
873.40
873.43
700.00
855.99

Velocity
fps
2.96
1.57
1.05
0.57
0.07
1.92
0.00

Pressure
psi
387.10
73.56
75.58
76.99
74.84
0.00
2.17

Headloss
/1000ft
4.53
1.41
1.07
0.35
0.01
2.53
-193.37

Pressure
psi
387.34
73.84
75.88
77.30
75.15
0.00
2.59

Headloss
/1000ft
4.50
1.40
1.06
0.34
0.01
2.49
-193.92

Chlorine
mg/L
0.00
0.00
0.00
0.00
0.00
1.00
0.00









Pump

Chlorine
mg/L
1.00
0.99
0.00
0.00
0.00
1.00
0.00









Pump








Reservoir
Tank


















Reservoir
Tank










Figure C.2 Excerpt from a Report File (continued from previous page)
                              180

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           Nodes Section

           The Nodes Section of the output report lists simulation results for those nodes and
           parameters identified in the [REPORT]  section of the input file. Results are listed for
           each reporting time step of an extended period simulation. The reporting time step is
           specified in the [TIMES] section of the input file. Results at intermediate times when
           certain hydraulic events occur, such as pumps turning on or off or tanks closing
           because they become empty or full, are not reported.

           To have nodal results reported the [REPORT] section of the input file must contain
           the  keyword NODES followed by a listing of the ID  labels of the nodes  to be
           included in the report. There can be several  such NODES lines in the file. To report
           results for all nodes use the command NODES ALL.

           The default set of reported quantities for nodes includes Demand, Head,  Pressure,
           and Water Quality. You can specify how many decimal places to use when listing
           results for a parameter by using commands  such as PRESSURE PRECISION 3 in
           the  input file (i.e.,  use 3  decimal places  when  reporting results for  pressure). The
           default precision is 2 decimal places for all quantities. You can filter the report to list
           only the occurrences of values below or above  a certain value by adding statements
           of the  form PRESSURE BELOW 20 to the input file.


           Links  Section

           The Links Section  of the output report lists simulation results for those links and
           parameters identified in the [REPORT] section  of the input file. The reporting times
           follow the same convention as was described for nodes in the previous section.

           As with nodes, to have any results for links reported you must include the keyword
           LINKS followed by a list of link ID labels in the [REPORT] section of the input file.
           Use the command LINKS ALL to report results for all links.

           The default parameters reported on for links includes Flow, Velocity, and Headless.
           Diameter, Length, Water Quality, Status, Setting, Reaction Rate, and Friction Factor
           can be  added to  these  by  using commands such  as  DIAMETER  YES  or
           DIAMETER PRECISION 0. The same conventions used with node  parameters for
           specifying reporting precision and filters also applies to links.
C.4    Binary Output File Format

           If a third file name is supplied to the command line that runs EPANET then the
           results for all parameters for all nodes and links for all reporting time periods will be
           saved to this file in a special binary format. This file can be used for special post-
           processing purposes. Data written to the file are 4-byte integers, 4-byte floats, or
           fixed-size strings whose size  is a multiple of 4 bytes. This allows the file to be
           divided conveniently into 4-byte  records. The file  consists of four sections of the
           following sizes in bytes:
                                         181

-------
 Section
 Prolog
 Energy Use
 Extended Period
 Epilog
where

Nnodes
Nlinks
Ntanks
Npumps
Nperiods
        Size in bytes
        852 + 20*Nnodes + 36*Nlinks + 8*Ntanks
        28*Npumps + 4
        (16*Nnodes + 32*Nlinks)*Nperiods
        28
number of nodes (junctions + reservoirs + tanks)
number of links (pipes + pumps + valves)
number of tanks and reservoirs
number of pumps
number of reporting periods
and all of these counts are themselves written to the file's Prolog or Epilog sections.

Prolog Section

The prolog section of the binary Output File contains the following data:
Item
Magic Number ( = 5 161 14521)
Version (= 200)
Number of Nodes
(Junctions + Reservoirs + Tanks)
Number of Reservoirs & Tanks
Number of Links
(Pipes + Pumps + Valves)
Number of Pumps
Number of Valves
Water Quality Option
0 = none
1 = chemical
2 = age
3 = source trace
Index of Node for Source Tracing
Flow Units Option
0 = cfs
1 =gpm
2 = mgd
3 = Imperial mgd
4 = acre -ft/day
5 = liters/second
6 = liters/minute
7 = megaliters/day
8 = cubic meters/hour
9 = cubic meters/day
Type
Integer
Integer
Integer
Integer
Integer
Integer
Integer
Integer
Integer
Integer
Number of Bytes
4
4
4
4
4
4
4
4
4
4
                             182

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Pressure Units Option
0 = psi
1 = meters
2 = kPa
Statistics Flag
0 = no statistical processing
1 = results are time-averaged
2 = only minimum values reported
3 = only maximum values reported
4 = only ranges reported
Reporting Start Time (seconds)
Reporting Time Step (seconds)
Simulation Duration (seconds)
Problem Title (1st line)
Problem Title (2nd line)
Problem Title (3rd line)
Name of Input File
Name of Report File
Name of Chemical
Chemical Concentration Units
ID Label of Each Node
ID Label of Each Link
Index of Start Node of Each Link
Index of End Node of Each Link
Type Code of Each Link
0 = Pipe with CV
1 = Pipe
2 = Pump
3=PRV
4 = PSV
5=PBV
6 = FCV
7 = TCV
8 = GPV
Node Index of Each Tank
Cross-Sectional Area of Each Tank
Elevation of Each Node
Length of Each Link
Diameter of Each Link
Integer
Integer
Integer
Integer
Integer
Char
Char
Char
Char
Char
Char
Char
Char
Char
Integer
Integer
Integer
Integer
Float
Float
Float
Float
4
4
4
4
4
80
80
80
260
260
16
16
16
16
4*Nlinks
4*Nlinks
4*Nlinks
4*Ntanks
4*Ntanks
4*Nnodes
4*Nlinks
4*Nlinks
There is a one-to-one correspondence between the order in which the ID labels for
nodes and links are written to the file and the index numbers of these components.
Also, reservoirs are distinguished from tanks by having their cross-sectional area set
to zero.


Energy Use Section

The  Energy Use section of the binary output  file immediately follows the Prolog
section. It contains the following data:
                               183

-------
Item
Repeated for each pump:
• Pump Index in List of Links
• Pump Utilization (%)
• Average Efficiency (%)
• Average Kwatts/Million Gallons (/Meter3)
• Average Kwatts
• Peak Kwatts
• Average Cost Per Day
Overall Peak Energy Usage
Type

Float
Float
Float
Float
Float
Float
Float
Float
Number of Bytes

4
4
4
4
4
4
4
4
The statistics reported in this section refer to the period of time between the start of
the output reporting period and the end of the simulation.
Extended Period Section

The Extended Period section of the binary Output File contains simulation results for
each reporting period of an analysis (the reporting start time and time step are written
to the Output File's Prolog section and the  number of steps is written to the Epilog
section). For each reporting period the following values are written to the file:
Item
Demand at Each Node
Hydraulic Head at Each Node
Pressure at Each Node
Water Quality at Each Node
Flow in Each Link
(negative for reverse flow)
Velocity in Each Link
Headless per 1000 Units of Length for Each Link
(Negative of head gain for pumps and total head
loss for valves)
Average Water Quality in Each Link
Status Code for Each Link
0 = closed (max. head exceeded)
1 = temporarily closed
2 = closed
3 = open
4 = active (partially open)
5 = open (max. flow exceeded)
6 = open (flow setting not met)
7 = open (pressure setting not met)
Setting for Each Link:
Roughness Coefficient for Pipes
Speed for Pumps
Setting for Valves
Reaction Rate for Each Link (mass/L/day)
Friction Factor for Each Link
Type
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Size in Bytes
4*Nnodes
4*Nnodes
4*Nnodes
4*Nnodes
4*Nlinks
4*Nlinks
4*Nlinks
4*Nlinks
4*Nlinks
4*Nlinks
4*Nlinks
4*Nlinks
                               184

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Epilog Section

The Epilog section of the binary output file contains the following data:
Item
Average bulk reaction rate (mass/hr)
Average wall reaction rate (mass/hr)
Average tank reaction rate (mass/hr)
Average source inflow rate (mass/hr)
Number of Reporting Periods
Warning Flag:
0 = no warnings
1 = warnings were generated
Magic Number ( = 5 161 14521)
Type
Float
Float
Float
Float
Integer
Integer
Integer
Number of Bytes
4
4
4
4
4
4
4
The mass units of the reaction rates both here and in the Extended Period output
depend on the concentration units assigned to the chemical being modeled. The
reaction rates listed in this section refer to the average of the rates seen in all pipes (or
all tanks) over the entire reporting period of the simulation.
                               185

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(This page intentionally left blank.)
              186

-------
APPENDIX  D - ANALYSIS  ALGORITHMS
D.1    Hydraulics

           The method used in EPANET to solve the flow continuity and headless equations
           that characterize the hydraulic state of the pipe network at a given point in time can
           be termed a hybrid node-loop approach.  Todini and Pilati (1987) and later Salgado et
           al. (1988)  chose to call it the  "Gradient Method".  Similar approaches have been
           described by Hamam and Brameller (1971) (the "Hybrid Method) and by  Osiadacz
           (1987)  (the "Newton Loop-Node  Method").  The only difference between these
           methods is the way in which link  flows are updated after a new trial solution for
           nodal heads has been found. Because Todini's approach is simpler, it was chosen for
           use in EPANET.

           Assume we have a pipe network with N junction nodes and NF fixed grade nodes
           (tanks and reservoirs). Let the flow-headloss relation in a pipe between nodes i and j
           be given as:

               Ht-H^h^rQl+mQt                                   D.I

           where H = nodal head, h = headless, r = resistance coefficient, Q = flow rate, n =
           flow exponent, and m = minor loss coefficient. The value of the resistance coefficient
           will depend on which friction headless formula is being used (see below). For pumps,
           the headless (negative of the head  gain) can be represented by a power law of the
           form

               hj]=-(o\h0-r(Qj]l(o)n)

           where h0 is the shutoff head for the pump, co is a relative speed setting, and r and n
           are the pump curve coefficients. The second set of equations that must be satisfied is
           flow continuity around all nodes:

                    •-=°      fori = l,...N.                            D.2
           where Dt is the flow demand at node i  and by convention, flow into  a node is
           positive. For a set of known heads at the fixed grade nodes, we seek a solution for all
           heads Hi and flows Qy that satisfy Eqs. (D.I) and (D.2).

           The Gradient solution method begins with an initial estimate of flows in each pipe
           that may not necessarily satisfy flow continuity. At each iteration of the method, new
           nodal heads are found by solving the matrix equation:

               AH = F                                                     D 3
                                         187

-------
where A = an (NxN) Jacobian matrix, H = an (Nxl) vector of unknown nodal heads,
and F = an (Nxl) vector of right hand side terms

The diagonal elements of the Jacobian matrix are:
while the non-zero, off-diagonal terms are:
where py is the inverse derivative of the headless in the link between nodes i and
with respect to flow. For pipes,
    * y
while for pumps
                  1
                    2m
    Pa =
         nco2r(Q  /coy
Each right hand side term consists of the net flow imbalance at a node plus a flow
correction factor:
where the last term applies to any links connecting node i to a fixed grade node f and
the flow correction factor jy is:
for pipes and
for pumps, where sgn(x) is  1 if x > 0 and -1 otherwise. (Qtj is always positive for
pumps.)

After new heads are computed by solving Eq. (D.3), new flows are found from:

                                                                D.4
                              188

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If the sum of absolute flow changes relative to the total flow in all links is larger than
some tolerance (e.g., 0.001), then Eqs. (D.3) and (D.4) are solved once again.  The
flow update formula (D.4) always results in flow continuity around each node after
the first iteration.

EPANET implements this method using the following steps:
    l.  The linear system of equations D.3 is solved using  a sparse matrix
       method based on node re-ordering (George and Liu,  1981). After re-
       ordering the nodes to minimize the amount of fill-in for matrix A, a
       symbolic factorization  is carried  out  so  that only the non-zero
       elements of A  need be stored and  operated on in memory. For
       extended period simulation this re-ordering and factorization is only
       carried out once at the start of the analysis.
    2 .  For the very first iteration, the flow in a pipe is chosen equal to the
       flow corresponding to a velocity of 1 ft/sec, while the flow through a
       pump equals  the  design  flow   specified  for  the pump.  (All
       computations are made with head in feet and flow in cfs).
    3 .  The resistance coefficient for a pipe (r) is computed as described in
       Table 3.1. For the Darcy-Weisbach headless  equation, the friction
       factor /is computed by different equations  depending on the flow's
       Reynolds Number (Re):

       Hagen - Poiseuille formula for Re < 2,000 (Bhave, 1991):
               Re
       Swamee and Jain approximation to the Colebrook - White equation for Re >
       4,000 (Bhave, 1991):

                       °'25
                 ,  (  £     5.74
                Ln\
                              09
                  \3.1d  Re

       Cubic Interpolation From Moody Diagram for 2,000 < Re < 4,000 (Dunlop,
       1991):

           / = (XI + R(X2 + R(X3 + X4)))
               2000
           X\ = 1FA-FB
           X2 = 0.128-17FA +
           X3 = -0.128 + 13FA-2FB
           X4 = R(0.032 - 3FA + 0.5FB)
           FA = {Y3\2
                              189

-------
                     0.00514215
             3. Id  Re09
                            £      5.74
        73 = -0.86859Zw -
                            .     400009J

    where e = pipe roughness and d = pipe diameter.


4.   The minor loss coefficient based on velocity head (K) is converted to
    one based on flow (m) with the following relation:

            0.02517^
        m =	
                d4
5.   Emitters at junctions are  modeled as a fictitious  pipe between the
    junction and a fictitious reservoir. The pipe's headless parameters
    are n = (1/y), r = (l/C)n, and m = 0 where C is the emitter's discharge
    coefficient and y is its pressure exponent. The head at the fictitious
    reservoir is the elevation of the junction. The computed flow through
    the fictitious pipe becomes the flow associated with the emitter.
6.   Open valves are assigned an r-value by assuming the open valve acts
    as a smooth pipe (f = 0.02) whose length is twice the valve diameter.
    Closed links are assumed to  obey a  linear headless relation with a
    large resistance factor, i.e., h =  108<2, so that/? = 10"8 and y = Q. For
    links where (r+m)Q < W7,p = 107 and y = Q/n.
7.   Status checks on pumps,  check valves  (CVs), flow control valves,
    and pipes connected to full/empty tanks are made after every other
    iteration, up until the 10th iteration. After this,  status checks are
    made only after convergence is achieved. Status checks on pressure
    control valves (PRVs and PSVs) are made after each iteration.
8.   During status checks, pumps are  closed if the head  gain is greater
    than the shutoff head (to prevent reverse flow).  Similarly,  check
    valves  are closed if the  headless through  them  is  negative (see
    below). When these conditions are not present, the link is re-opened.
    A similar  status  check is made for links connected to empty/full
    tanks. Such links are closed if the difference in head across the link
    would cause an empty tank to drain or a full tank to fill. They are re-
    opened at the next status check if such conditions no longer hold.
9.   Simply checking if h < 0 to determine if a check valve should  be
    closed or open was found to cause cycling between these two states
    in  some networks  due  to  limits  on  numerical  precision. The
    following procedure was devised to provide a more robust test of the
    status of a check valve (CV):
                           190

-------
       if |/?|> Htol then
           if h < -Htol then   status = CLO SED
           if Q < -Qtol then   status = CLO SED
           else              status = OPEN
       else
           if Q < -Qtol then   status = CLO SED
       else                  status = unchanged

   where Htol = 0.0005 ft and Qtol = 0.001 cfs.

10. If the status check closes an open pump, pipe, or CV, its flow is set
   to 10"6 cfs. If a pump is re-opened, its flow is computed by applying
   the current head gain to its characteristic curve.  If a pipe or CV is re-
   opened, its flow is determined by solving Eq. (D.I) for Q under the
   current headless h, ignoring any minor losses.
11. Matrix coefficients for pressure breaker valves (PBVs) are set to the
   following: p = 10s and y = 108Hset, where Hset is the pressure drop
   setting for the valve (in feet).  Throttle control valves (TCVs) are
   treated as pipes with r as described in item 6 above and m taken as
   the converted value of the valve setting (see item 4 above).
12. Matrix coefficients for pressure reducing, pressure  sustaining,  and
   flow control valves (PRVs, PSVs, and FCVs) are computed after all
   other links have been analyzed. Status checks  on PRVs and PSVs
   are made as described in item  7 above. These valves  can either be
   completely open,  completely closed,  or active  at their pressure or
   flow setting.

is. The logic used to test the status of a PRV is as follows:

       If current status = ACTIVE then
           if Q < -Qtol               then new status = CLOSED
           if Hi < Hset + Hml - Htol   then new status = OPEN
                                    else new status = ACTIVE

       If curent status = OPEN then
           if Q < -Qtol               then new status = CLOSED
           if Hi > Hset + Hml + Htol  then new status = ACTIVE
                                    else new status = OPEN

       If current status = CLOSED then
           if Hi > Hj + Htol
           and Hi < Hset - Htol       then new status = OPEN
           ifHi>Hj+Htol
           and Hj <  Hset - Htol       then new status = ACTIVE
                                    else new status = CLOSED

   where Q is  the current flow through the valve, Hi is its upstream
   head, Hj is its  downstream  head,  Hset  is  its pressure  setting
   converted to head, Hml is the minor loss when the valve is open (=
   mQ2), and Htol and Qtol are the same values used for check valves in
                          191

-------
    item 9 above.  A similar set of tests is used for PSVs, except that
    when testing against Hset, the i and j subscripts are switched as are
    the > and < operators.
14 .  Flow through an active PRV is  maintained to force continuity at its
    downstream node while flow through a PSV does the same  at its
    upstream node. For an active PRV from node i to j :
    This forces the head at the downstream node to be at the valve setting Hset.
    An equivalent assignment of coefficients is made for an active PSV except
    the subscript for F and A is the upstream node i. Coefficients for open/closed
    PRVs and PSVs are handled in the same way as for pipes.
15 .  For an active FCV  from node i to j with flow setting Qset, Qset is
    added  to the  flow  leaving node i  and entering  node j, and is
    subtracted from Ft and added to Fj. If the head at node i is less than
    that at node j, then the valve cannot deliver the flow and it is treated
    as an open pipe.
16.  After initial convergence  is  achieved  (flow convergence plus no
    change  in  status for PRVs and  PSVs), another status check on
    pumps, CVs, FCVs, and links to tanks is made. Also, the  status of
    links controlled by pressure switches (e.g., a pump controlled by the
    pressure at a junction node) is checked.  If any status change occurs,
    the iterations must  continue for at least two more iterations (i.e., a
    convergence check is skipped on the very next iteration). Otherwise,
    a final solution has been obtained.
17 .  For extended period simulation (EPS), the following procedure is
    implemented:
    a.  After a solution is found for the current time period,  the time
       step for the next solution is the minimum of:

       •   the time until a new demand period begins,

       •   the shortest time for a tank to fill or drain,

       •   the  shortest time  until a tank level reaches  a point  that
           triggers a change in status for some  link (e.g.,  opens or
           closes a pump) as stipulated in a simple control,

       •   the next time until a simple timer control on a link kicks in,

       •   the next time at which a rule-based control causes a status
           change somewhere in the network.

       In  computing the  times  based on tank levels, the latter are
       assumed to change in a linear fashion based on the current flow
       solution. The activation time of rule-based controls is computed
       as follows:
                           192

-------
                      •   Starting at the current time, rules are evaluated at a rule time
                          step. Its default value  is 1/10 of the normal hydraulic time
                          step (e.g., if hydraulics are updated every hour, then rules are
                          evaluated every 6 minutes).

                      •   Over this rule  time step, clock time is updated,  as are the
                          water levels in  storage tanks (based on the last set of pipe
                          flows computed).

                      •   If a rule's conditions are satisfied, then its actions are  added
                          to a list.  If an action  conflicts with one  for the  same link
                          already on the  list then the action  from  the  rule with the
                          higher priority stays on the  list and the other is removed. If
                          the priorities are the same then the original action stays on
                          the list.

                      •   After all rules are  evaluated, if the list is not empty then the
                          new actions are taken. If this causes the status of one or more
                          links to change then a new hydraulic solution is computed
                          and the process begins anew.

                      •   If no status changes were called for, the action list is cleared
                          and the next rule time step  is taken unless the normal
                          hydraulic time step has elapsed.
                      Time is advanced by the computed time step, new demands are
                      found, tank  levels are adjusted based on  the  current flow
                      solution, and link control rules are checked to determine  which
                      links change status.
                      A new set of iterations with Eqs. (D.3) and (D.4) are begun at the
                      current set of flows.
D.2    Water Quality
           The  governing equations for  EPANET's water quality solver  are  based on the
           principles of conservation of mass coupled with reaction kinetics. The following
           phenomena are represented (Rossman et al., 1993; Rossman and Boulos, 1996):


           Advective Transport in Pipes

           A dissolved substance will travel down the length of a pipe with the same average
           velocity as the carrier fluid while at the  same time reacting (either growing or
           decaying) at  some given rate.  Longitudinal dispersion is usually not an important
           transport mechanism under most  operating conditions. This means there is  no
           intermixing  of mass between adjacent parcels  of water traveling  down  a pipe.
           Advective transport within a pipe is represented with the following equation:

                                          193

-------
where Ct = concentration (mass/volume) in pipe i as a function of distance x and time
t,  tt, =  flow  velocity (length/time)  in  pipe  i,  and  r  =  rate  of  reaction
(mass/volume/time) as a function of concentration.


Mixing at Pipe Junctions

At junctions receiving inflow from two or more pipes, the mixing of fluid is taken to
be complete and instantaneous. Thus the  concentration of a substance  in water
leaving the junction is simply the flow-weighted sum  of the concentrations from the
inflowing pipes. For a specific node k one can write:
where i = link with flow leaving node k, Ik = set of links with flow into k, Z; = length
of link j, Qj = flow (volume/time) in link j, Qk,ext = external source flow entering the
network at node k, and Ckext = concentration of the external flow entering at node k.
The notation Cj\x=0 represents the concentration at the start of link i, while C^X=L is the
concentration at the end of the link.
Mixing in Storage Facilities

It is convenient to assume that the contents of storage facilities (tanks and reservoirs)
are completely mixed. This is a reasonable assumption for many tanks operating
under fill-and-draw conditions providing that sufficient momentum flux is imparted
to the inflow (Rossman and Grayman, 1999). Under completely mixed conditions the
concentration throughout the tank is a blend of the current contents and that of any
entering water. At the same time, the internal concentration could be changing due to
reactions. The following equation expresses these phenomena:
                                                                   D.7
where Vs = volume in storage at time t, Cs = concentration within the storage facility,
Is = set of links providing flow into the facility, and Os = set of links withdrawing
flow from the facility.


Bulk Flow Reactions

While a substance moves down a pipe or resides in storage  it can undergo reaction
with constituents in the water column. The rate of reaction can generally be described
as a power function of concentration:

    r = kC"
                               194

-------
where  k =  a reaction  constant and n = the reaction  order. When  a limiting
concentration exists on  the ultimate growth or loss  of a substance then the rate
expression becomes

    R = Kh(CL-C)C("-l)        forn>Q,Kb>0

    R = Kb(C-CL)C("-l}        forn>Q,Kb 0, Kb > 0, n = 1):

           R = Kh(CL-C)

       This model can be applied to the growth of disinfection by-products,
       such as trihalomethanes, where the  ultimate formation of by-product
       (CL) is limited by the amount of reactive precursor present.


    •   Two-Component, Second Order Decay (CL ^ 0, Kb < 0, n = 2):

           R = KhC(C-CL)

       This model assumes that substance A reacts with substance B in
       some unknown  ratio  to  produce  a  product  P.  The  rate  of
       disappearance of  A is  proportional to the  product of A and B
       remaining. CL can be either  positive or  negative, depending  on
       whether either component A or B  is in excess, respectively. Clark
       (1998) has had success in applying this model to chlorine decay data
       that did not conform to the simple first-order model.


    •   Michaelis-Menton Decay Kinetics (CL > 0, Kb < 0, n < 0):
                CL-C

       As a special case, when a negative reaction order n is specified,
       EPANET will utilize the Michaelis-Menton rate equation, shown
       above for a decay reaction. (For growth reactions the denominator
       becomes CL + C.) This rate equation is  often used  to  describe
       enzyme-catalyzed reactions and microbial growth. It produces first-
       order behavior at low concentrations  and zero-order  behavior at
       higher concentrations. Note that for decay reactions, CL must be set
       higher than the initial concentration present.
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       Koechling  (1998) has applied Michaelis-Menton kinetics to model
       chlorine decay in a number of different waters and found that both Kb
       and  CL could be related to the  water's  organic  content and  its
       ultraviolet absorbance as follows:


           Kb=-032UVA-^WOUVA^
             b                   DOC

           CL =4.9WVA-\.9\DOC

       where UVA = ultraviolet absorbance at 254 nm (I/cm) and DOC =
       dissolved organic carbon concentration (mg/L).

       Note: These expressions apply only for values of Kb and CL used
       with Michaelis-Menton kinetics.


    •  Zero-Order growth (CL = 0, Kb = 1, n = 0)

              R = 1.0

       This special case can be used to model water age, where with each
       unit of time the "concentration" (i.e., age) increases by one unit.


The relationship between the bulk rate constant seen at one temperature (Tl) to that
at another temperature (T2) is often expressed using a  van't Hoff - Arrehnius
equation of the form:

     V     V  f\T2-Tl
where 6 is a constant. In one investigation for chlorine, 9 was estimated to
be 1.1 when Tl was 20 deg. C (Koechling, 1998).


Pipe Wall Reactions

While flowing through pipes, dissolved substances can be transported to the pipe wall
and react with material such  as corrosion products or biofilm that are on or close to
the wall. The amount of wall area available for reaction and the rate of mass transfer
between the bulk fluid and the wall will also influence the overall  rate  of this
reaction. The  surface area per unit volume, which for a pipe equals  2 divided by the
radius, determines the former factor. The latter factor can be represented by a mass
transfer coefficient whose value depends on the molecular diffusivity of the reactive
species  and on the Reynolds number of the flow (Rossman et. al,  1994). For first-
order kinetics, the rate of a pipe wall reaction can be expressed as:
    r=
                               196

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where kw = wall reaction rate constant (length/time), kf= mass transfer coefficient
(length/time), and R = pipe radius. For zero-order kinetics the reaction rate cannot be
any higher than the rate of mass transfer, so

    r=MIN(kw,kfC)(2/R)

where kw now has units of mass/area/time.

Mass transfer  coefficients are  usually  expressed  in terms  of  a dimensionless
Sherwood number (Sh):
    i     w
    kf = Sh —
     f      d

in which D = the molecular diffusivity of the species being transported (Iength2/time)
and d  = pipe  diameter.  In fully developed laminar flow, the  average Sherwood
number along the length of a pipe can be expressed as
       — J . O J ~
                   0.04[(W/Z)Re&]2/3
in which Re = Reynolds number and Sc = Schmidt number (kinematic viscosity of
water divided by the diffusivity of the chemical) (Edwards et.al, 1976). For turbulent
flow the empirical correlation of Notter and Sleicher (1971) can be used:
                   0'88
    Sh = 0.0149 Re
System of Equations

When applied to a network as a whole, Equations D.5-D.7 represent a coupled set of
differential/algebraic equations with time-varying coefficients that must be solved for
Ct in each pipe  i and Cs in  each storage facility s. This solution is subject to the
following set of externally imposed conditions:

    •  initial conditions that specify Ct for all x in each pipe i and Cs in each
       storage facility s at time 0,

    •  boundary conditions that specify values for Ckext and  Qkext for all
       time t at each node k which has external mass inputs

    •  hydraulic conditions which specify the volume  Vs  in each storage
       facility s and the flow Qt in each link i at all  times t.
                               197

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Lagrangian Transport Algorithm

EPANET's water quality simulator uses a Lagrangian time-based approach to track
the fate of discrete parcels of water as they move along pipes and mix together at
junctions between fixed-length time steps (Liou and Kroon, 1987).  These water
quality time  steps are  typically much shorter than  the hydraulic time  step (e.g.,
minutes rather than hours) to accommodate the short times of travel that can occur
within pipes.  As time progresses, the size of the most upstream segment in a pipe
increases as water enters the pipe while an equal loss in size of the most downstream
segment occurs as water leaves the link. The size of the segments in between these
remains unchanged. (See Figure D.I).

The following steps occur at the end of each such time step:
    i. The water quality in  each segment is updated to reflect any reaction
       that may have occurred over the time step.
    2. The water from the leading segments of pipes with flow into  each
       junction is blended together to compute a new water quality value at
       the junction.  The volume contributed from each segment equals the
       product of its pipe's flow rate and the time step. If this volume
       exceeds that  of the segment then the segment is destroyed and the
       next one in line behind it begins to contribute its volume.
    3. Contributions from outside  sources are added to the quality values at
       the junctions. The quality in storage tanks is updated  depending on
       the method used to model mixing in the tank (see below).
    4. New  segments are created  in pipes with flow out of each junction,
       reservoir, and tank. The segment volume equals the product of the
       pipe flow and the time step. The segment's water quality equals the
       new quality value computed for the node.

To cut down  on the number of segments, Step 4 is only carried out if the new node
quality differs by a  user-specified tolerance from that of the last segment  in the
outflow pipe. If the difference  in quality is below the tolerance then the size of the
current last segment in the outflow pipe is simply increased by the volume flowing
into the pipe over the time step.

This process is then repeated for the next water-quality time step. At the start of the
next hydraulic time step the  order  of segments in any links that experience a flow
reversal is switched.  Initially each pipe in the network consists of a single segment
whose quality equals the initial quality assigned to the upstream node.
                               198

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                                                 Time t
                                                Time t + At
                 Figure D.I  Behavior of Segments in the Lagrangian Solution Method
D.3    References
          Bhave, P.R. 1991. Analysis of Flow in Water Distribution Networks.  Technomic
              Publishing. Lancaster, PA.

          Clark, R.M.  1998.  "Chlorine demand and Trihalomethane formation  kinetics: a
              second-order model", Jour. Env. Eng.,Vo\. 124, No. l,pp. 16-24.

          Dunlop, E.J.  1991.  WADI Users Manual. Local  Government Computer Services
              Board, Dublin, Ireland.

          George, A. & Liu, J. W-H. 1981. Computer Solution of Large Sparse Positive
              Definite Systems. Prentice-Hall, Englewood Cliffs, NJ.

          Hamam, Y.M, & Brameller, A. 1971.  "Hybrid  method for the solution of piping
              networks", Proc. IEE, Vol. 113, No. 11, pp. 1607-1612.
                                        199

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Koechling, M.T. 1998. Assessment and Modeling of Chlorine Reactions with Natural
    Organic Matter: Impact of Source Water Quality and Reaction Conditions, Ph.D.
    Thesis, Department of Civil and Environmental Engineering,  University of
    Cincinnati, Cincinnati, Ohio.

Liou, C.P. and Kroon, J.R.  1987. "Modeling  the  propagation  of waterborne
    substances in distribution networks", J. AWWA, 79(11), 54-58.

Notter, R.H. and Sleicher, C.A. 1971. "The eddy diffusivity in the turbulent boundary
    layer near a wall", Chem.  Eng. Sci., Vol. 26, pp. 161-171.

Osiadacz, A.J.  1987. Simulation and Analysis of Gas Networks. E.  & F.N. Spon,
    London.

Rossman, L.A., Boulos, P.P., and  Airman, T. (1993).  "Discrete  volume-element
    method for network water-quality models", J.  Water Resour. Ping, and Mgmt,,
    Vol. 119, No. 5, 505-517.

Rossman, L.A., Clark, R.M.,  and  Grayman, W.M.  (1994). "Modeling  chlorine
    residuals in drinking-water distribution systems", Jour. Env. Eng., Vol.  120, No.
    4, 803-820.

Rossman, L.A. and Boulos,  P.P.  (1996). "Numerical methods for modeling water
    quality in  distribution  systems:  A comparison", J.  Water Resour. Ping,  and
    Mgmt, Vol. 122, No. 2, 137-146.

Rossman, L.A. and Grayman, W.M. 1999.  "Scale-model  studies  of mixing in
    drinking water storage tanks", Jour. Env. Eng., Vol. 125, No. 8, pp. 755-761.

Salgado, R., Todini, E., & O'Connell, P.E. 1988. "Extending the gradient method to
    include pressure regulating valves in pipe networks". Proc. Inter. Symposium on
    Computer Modeling of Water Distribution Systems, University of Kentucky, May
    12-13.

Todini, E. & Pilati, S. 1987. "A gradient method for the analysis of pipe networks".
    International Conference on Computer Applications for Water  Supply  and
    Distribution, Leicester Polytechnic, UK, September 8-10.
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