Contents
 EPANET 2.0 Help Contents

EPANET is a program that performs extended period simulation of hydraulic and water quality behavior within drinking water distribution systems.

Introduction

EPANET's Workspace

Working with Projects

Working with Objects

Working with the Map

Running an Analysis

Viewing Results

Printing

Importing and Exporting

Frequently Asked Questions

Reference


Introduction

The following topics provide an introduction to using the EPANET modeling system.

What is EPANET

Hydraulic Modeling Capabilities

Water Quality Modeling Capabilities

Network Components

Water Quality Reactions

Steps in Using EPANET


What is EPANET

EPANET performs extended period simulation of hydraulic and water quality behavior within pressurized pipe networks.  A network can consist 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.

The Windows version of 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.

EPANET was developed by the Water Supply and Water Resources Division (formerly the Drinking Water Research Division) of the U.S. Environmental Protection Agency's National Risk Management Research Laboratory.


Network 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. Click on the name of an object  to learn more about it.

In addition to these physical components, an EPANET project can contain the following objects that describe the performance and operation of a distribution system:

 Curves

 Patterns

 Controls

 Analysis Options


Water Quality Modeling Capabilities

EPANET includes 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 (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

By employing these features, EPANET can be used to 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

Contaminant propagation events


EPANET's Workspace

The EPANET workspace consists of the following elements:

Menu Bar

Toolbars

Status Bar

Network Map

Database Browser

Map Browser

Property Editor

Aspects of the workspace appearance and other program features can be customized by setting Program Preferences.


Menu Bar

The Menu Bar located across the top of the EPANET workspace contains a collection of menus used to control the program. These menus include:

File	Edit	View	Project	Window	Help


Toolbars

Toolbars provide shortcuts to commonly used operations. There are two such toolbars:

General 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 | Toolbar.

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Network Map

The Network Map provides a planar schematic diagram of the objects comprising a water distribution network. Selected  properties of these objects, such as water quality at nodes or flow velocity in links, can be displayed by using different colors. New objects can be directly added to the map and existing objects can be clicked on for editing, deleting, and repositioning. 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.

See Also:

Working with the Map


Status Bar

The Status Bar appears at the bottom of the EPANET workspace and is divided into four sections:

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 - the faucet icon shows running water when results of an analysis are available

XY Location - displays coordinates of current map location


Working with Projects

Project files contain all of the information used to model a network. They are usually named with a .NET extension. This section describes how to create, open, and save EPANET projects and set certain default properties.

Creating a new project

Opening an existing project

Saving a project

Setting default properties

Registering calibration data

Viewing a project summary


Working with Objects

EPANET uses various types of objects to model a distribution system. This section describes what these objects are and how they can be created, selected, edited, deleted, and repositioned.

Types of objects

Adding objects

Selecting an object

Editing an object

Copying and pasting objects

Deleting an object

Moving an object

Selecting a group of objects

Editing a group of objects


Working with the Map

EPANET can display a map of the pipe network being modeled. This section describes how you can manipulate this map to enhance your visualization of the system being modeled.

Selecting a map view

Setting the map scale

Zooming in or out

Panning the map

Finding an object

Using the map legend

Using the Overview Map

Setting map display options


Analyzing a Network

After a network has been suitably described, its hydraulic and water quality behavior can be analyzed. This section describes how to specify options to use in the analysis, how to start the analysis and how to troubleshoot problems that might have occurred with the analysis.

Setting analysis options

Running an analysis

Troubleshooting results


Viewing Results

This section describes the different ways in which the results of an analysis as well as the basic network input data can be viewed.

Viewing results on the map

Viewing results with a graph

Viewing results with a table

Viewing a report


Printing

This section describes how to print 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.

Selecting a printer

Setting the page format

Previewing the page

Printing the current view


Importing and Exporting

This section describes EPANET's capabilities to import and export project scenarios and network maps as well as copy data and charts to file or to the clipboard.

Project scenarios

Importing a project scenario

Exporting a project scenario

Importing a partial network

Importing a network map

Exporting a network map

Exporting to a text file

Copying to file or to the clipboard


Reference

Table of Units

Error Messages


Types of Objects

EPANET models a pipe network using the following types of objects:

Nodes:

Junctions

Reservoirs

Tanks

Links:

Pipes

Pumps

Valves

Notation

Map Labels

Operational

Time Patterns

Curves

Controls

Analysis Options


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

water demand

initial water quality.

The output results computed for junctions are

hydraulic head

pressure

water quality.

Junctions can also:

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

be represented as an emitter (or sprinkler) where the outflow rate is dependent on the pressure

See Also:

Junction Properties


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 from a file
Export	Exports network data or map to a file
Page Setup	Sets page margins and orientation for printing
Print Preview	Previews the printed page
Print	Prints the current view
Preferences	Sets program preferences
Exit	Exits EPANET


View Menu

The View Menu controls how the network map and analysis results are viewed.

Command	Description
Full Extent	Redraws the map at full extent
Rescale Map	Rescales the map
Pan	Pans across the map
Zoom In	Zooms in on the map
Zoom Out	Zooms out on the map
Node Legend	Displays/modifies the Node legend
Link Legend	Displays/modifies the Link legend
Overview Map	Toggles the Overview Map on/off
Find	Locates a specific item on the map
Query	Searches for nodes/links on the map that meet specific criteria
Report	Generates a report on selected results
Graph	Provides a graph of results
Table	Provides a tabular view of results
Toolbars	Toggles the toolbars on/off
Options	Sets options for the active window


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 property for a reservoir is its piezometric head (equal to the water surface elevation if the reservoir is not under pressure)  and 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.

A reservoir cannot be directly connected by a link to another reservoir or tank. If such a connection is required then an intermediate junction must be used.

See Also:

Reservoir Properties


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

diameter (or shape if non-cylindrical)

minimum and maximum levels

initial water quality.

The principal computed outputs are:

head (water level)

water quality.

Tanks are required to operate within their minimum and maximum levels. EPANET will close off a tank's connecting pipes if it wants to drain when already at its minimum level or fill when at its maximum level.

Tanks can also serve as water quality source points.

A tank cannot be directly connected by a link to another tank or reservoir. If such a connection is required then an intermediate junction must be used.

See Also:

Tank Properties


Pipes

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

diameter

length

roughness coefficient

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

The latter parameter allows pipes to implicitly contain shutoff valves and check valves (which allow flow in only one direction).

The water quality inputs for pipes consist of

bulk reaction coefficient

wall reaction coefficient.

Computed outputs for pipes include

flow rate

velocity

head loss

friction factor

reaction rate

water quality.

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

Hazen-Williams Formula

Darcy-Weisbach Formula

Chezy-Manning Formula

Minor losses caused by bends and fittings can also be accounted for by assigning the pipe a minor loss coefficient.

Pipes can also be set open or closed at preset times, when tank levels fall below or above certain set-points, or when nodal pressures fall below or above certain set-points by the use of Controls.

See Also:

Pipe Properties


Pumps

Pumps are devices that impart energy to a fluid thereby raising its hydraulic head.

The principal input parameter for a pump is 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.

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.

Pumps can be turned on and off at preset times, when tank levels fall below or above certain set-points, or when nodal pressures fall below or above certain set-points through the use of controls and time patterns.

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.

EPANET can also compute the energy consumption and cost of a pump. Either pump-specific efficiency curves and energy pricing parameters can be supplied or global energy options will be used.

See Also:

Pump Properties


Valves

Valves are used to control the pressure or flow at a specific point in the network.

Shutoff and check valves, which completely open or close pipes, are not considered as separate valve components but are instead included as a property of the pipe in which they are placed (see Pipe Properties).

The different types of valves include:

PRV (Pressure Reducing Valve)

PSV (Pressure Sustaining Valve)

PBV (Pressure Breaker Valve)

FCV (Flow Control Valve)

TCV (Throttle Control Valve)

GPV (General Purpose Valve)

The General Purpose Valve (GPV) can be used to represent a link where the flow - head loss relationship is supplied by the user instead of following one of the standard hydraulic formulas.

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 Controls. (To restore a valve's control status after its status has been overridden to open or closed use a control that specifies a value for the valve setting.)

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.

See Also:

Valve Properties


Map Labels

Map Labels are text labels that can be placed anywhere on the network map to identify special locations or provide other information.

See also:

Map Label Properties


Time Patterns

A Time Pattern is a collection of multipliers that can be applied to a quantity to allow it to vary over time. Water 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 set with the project's Time Options. 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 interval. 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 periods 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	1	2	3	4	5	6
Multiplier	0.5	0.8	1.0	1.2	0.9	0.7
Then during the simulation the actual demand exerted at this node will be as follows:

Hour	0-4	4-8	8-12	12-16	16-20	20-24	24-28
Demand	5	8	10	12	9	7	5
See Also:

Adding a Time Pattern

Editing a Time Pattern


Curves

Curves are objects that contain data pairs representing a relationship between two variables. 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

See Also:

Adding a Curve,

Editing a Curve


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 depend on only a single condition in the network (e.g., a water level in a certain tank) while rule-based controls depend on a number of conditions occurring simultaneously.

See Also:

Editing Controls


Analysis Options

Analysis Options control the way in which a network is analyzed. There are five different categories of options:

Hydraulics Options

Quality Options

Reactions Options

Time Options

Energy Options


Creating a New Project

To create a new project:

1.	Select File | New or click the [image] button on the General toolbar.

2.	You will be prompted to save the exiting 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.


Opening an Existing Project

To open an existing project stored on disk:

1.	Either select File | Open or click the [image] button on the General 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 standard Open File dialog box.

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 can distinguish between the two types of files no matter what their naming.


Saving a Project

To save a project under its current name:

Either select File | Save or click the [image] button on the General toolbar.

To save a project using a different name:

1.	Select File | Save As.

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

Projects are always saved as binary .NET files. To save a project's data as readable ASCII text, use the File | Export Data command.


Program Preferences - General

The General page of the Program Preferences dialog box allows you to modify the following program preferences:

Property	Description
Bold Fonts	Uses bold fonts in all newly created windows.
Blinking Map Hiliter	Makes the selected node, link, or label on the map blink on and off.
Flyover Map Labeling	Displays the ID label and value of the current view variable in a hint-style box whenever the mouse is placed over a node or link on the network map.
Confirm Deletions	Displays a confirmation dialog box before deleting any object.
Automatic Backup File	Saves a backup copy of a newly opened project to disk named with a .bak extension.
Temporary Folder	Name of the folder where EPANET writes its temporary files
NOTE:	The temporary folder must be a folder (directory) 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 folder (usually c:\Windows\Temp).


Project Defaults - ID Labels

The ID Labels page of the Project Defaults dialog form is used to determine how EPANET will assign default ID labels to network components when they are first created.

For each type of object enter a label prefix (leave blank if an object's default ID will simply be a number).

Enter 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 its ID label can always be changed by using the Property Editor.


Project Defaults - Hydraulics

The Hydraulics page of the Project Defaults dialog contains the same set of hydraulic options as the project's Hydraulic Options accessed from the Browser. They are repeated on the Project Defaults dialog so that they can saved for use with future projects as well as with the current one.


Project Defaults - Properties

The Properties page of the Project Defaults dialog form sets default property values for newly created nodes and links. These properties include:

Elevation for nodes

Diameter for tanks

Maximum level for tanks

Length for pipes

Diameter for pipes

Roughness for pipes

After a node or link has been created its properties can always be modified by using the Property Editor.


Program Preferences - Formats

The Formats page of the Program Preferences dialog box controls how many decimal places are displayed when results for computed variables are reported.

Use the dropdown list boxes to select a specific Node or Link variable.

Use the spin edit boxes to select the number of decimal places to use when displaying computed results for the variable.


Analysis Options - Hydraulics

Option	Description
Flow Units	Units in which nodal demands and link flow rates are expressed. Choices are: CFS (cubic feet per second) GPM (gallons per minute) MGD (million gallons per day) LPS (liters per second) Choosing CFS, GPM, or MGD implies that the units for all other network quantities are Customary US. Choosing LPS 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.
Head Loss Equation	Equation used to compute head loss as a function of flow rate in a pipe. Choices are: Hazen-Williams Darcy-Weisbach Chezy-Manning
Specific Gravity	Ratio of the density of the fluid being modeled to that of water at 4 deg. C (unitless).
Relative Viscosity	Kinematic viscosity of the fluid being modeled relative to the viscosity of water at 20 deg. C (1.0 centistokes or 0.94 sq ft/day).
Maximum Trials	Maximum number of trials used to find a hydraulic solution for the current simulation time step.
Accuracy	Signals that a hydraulic solution has been reached when the sum of all flow changes at the current trial divided by the sum of all link flows is less than this value.
If Unbalanced	Action to take if Maximum Trials is exceeded. 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.
Default Pattern	ID label of a time pattern to be applied to demands at those junctions where no time pattern is specified. If no such time pattern exists then demands will not vary at these locations.
Status Report	Choices are NONE (no status report) YES (normal status reporting)  FULL (full reporting) Full reporting includes error results from each trial of the hydraulic analysis in each time period and is only useful for debugging purposes.


Analysis Options - Quality

Option	Description
Parameter	Type of water quality parameter being modeled. Choices include: None (no quality analysis), Chemical (compute chemical concentration), Age (compute water age), Trace (trace flow from a specific node). In lieu of Chemical, you can  enter the actual name of the chemical being modeled (e.g., Chlorine).
Mass Units	Mass units used to express concentration. Choices are mg/L or ug/L. Units for Age and Trace analyses are fixed at hours and percent, respectively.
Relative Diffusivity	Molecular diffusivity of the chemical being modeled relative 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 half as fast, etc. Only used when modeling pipe wall reactions.
Trace Node	ID label of the node whose flow is being traced. Applies only to flow tracing analyses.
Maximum Segments	Maximum number of sub-segments (or water parcels) that can exist within a pipe. If this number is exceeded a warning message is issued and the accuracy of the results might suffer. The default setting is 1000.
Quality Tolerance	Smallest change in quality that will cause a new parcel of water to be created in a pipe. Default setting is 0.01 for all types of analyses (chemical, water age, and flow 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.


Analysis Options - Reactions

Option	Description
Bulk Reaction Order	A non-negative number representing the order of reactions occurring in the bulk flow. See Bulk Flow Reaction Rates.
Wall Reaction Order	Reaction rate order for wall reactions. Can either be FIRST for first-order reaction or ZERO for constant rate reaction. See Pipe Wall Reaction Rates.
Global Bulk Coefficient	Default bulk reaction rate coefficient (Kb) assigned to all pipes. The global coefficient can be overridden by editing this property for specific pipes. Use positive number for growth, 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 reaction order.
Global Wall Coefficient	Wall reaction rate coefficient (Kw) assigned to all pipes. Can be overridden by editing this property for specific pipes. Use positive number for growth, 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.
Limiting Concentration	Minimum concentration that a chemical can decay to or maximum concentration that it can grow to. Leave blank if not applicable.
Wall Coeff. Correlation	Factor correlating wall reaction coefficient to pipe roughness. See Wall Reaction - Pipe Roughness Correlation for more details.


Wall Reaction - Pipe Roughness Correlation

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 has the ability to allow each pipe's wall reaction coefficient (Kw) be made a function of the coefficient used to describe its roughness. A different function applies depending on the formula used to compute head loss through the pipe:

Head Loss 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

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.


Analysis Options - Times

Option	Description
Total Duration	Total length of a simulation in hours. Use 0 to run a single period hydraulic analysis.
Hydraulic Time Step	Time interval between recomputation of system hydraulics in hours. Normal default is 1 hour.
Quality Time Step	Time interval between routing of water quality constituent in minutes. Normal default is 5 mins.
Pattern Time Step	Time interval used with all time patterns in hours. Normal default is 1 hour.
Pattern Start Time	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.
Reporting Time Step	Time interval between times at which computed results are reported in hours. Normal default is 1 hour.
Report Start Time	Hours into simulation at which computed results begin to be reported. Normal default is 0.
Starting Time of Day	Clock time  (e.g., 7:30 am, 10:00 pm) at which simulation begins. Default is 12:00 am (midnight).
Time Averaged	If selected, only time-averaged values (beginning at the Report Start Time) of computed results will be reported.
NOTE:	To run a single-period hydraulic analysis (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.


Analysis Options - Energy

Energy Analysis Options are default parameters used to compute pumping energy and cost when no specific energy parameters are assigned to a given pump.

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.
Demand Charge	Additional energy charge per maximum kilowatt usage.


Hydraulic Modeling Capabilities

Full-featured and accurate hydraulic modeling is a prerequisite for doing effective water quality modeling. EPANET includes the following  hydraulic modeling capabilities:

places no limit on the size of network that can be modeled

computes friction head loss using either Hazen-Williams, Darcy-Weisbach, or Chezy-Manning equations

includes minor head losses for bends, fittings, etc.

models constant or variable speed pumps

computes pumping energy and cost

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


Property Editor

The Property Editor (shown below) 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 Database Browser) and double-clicked or the Browser's Edit button is clicked.

The following points help explain how to use the Editor:

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.

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

- a text box where you type in a value

- a dropdown combo 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

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

The field in the Editor which 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 fields.

To begin editing the field 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 field; to cancel press the Esc key.

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

The window can be hidden by clicking the button in the upper right corner of its title bar.


General Toolbar

The General Toolbar contains speed buttons for commonly used commands on the File and View menus.

	Opens a new project
	Opens an existing project
	Saves the current project
	Prints the currently active window
	Copies selection to clipboard or to file
	Deletes currently selected item
	Finds a specific item on the map
	Runs a simulation
	Runs a visual query on the map
	Creates a new graph view of results
	Creates a new table view of results
	Modifies options for the currently active view


Map Toolbar

The Map Toolbar contains buttons for working with the Network Map.

	Selects an item on the map
	Selects a group of items on the map
	Pans across the map
	Zooms in on the map
	Zooms out on the map
	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


Setting Program Preferences

To set program preferences:

1.	Select File | Preferences.

2.	A Preferences dialog form will appear allowing you to select preferences for the following categories:

General Preferences

Formatting Preferences


Junction Properties

Property	Description
Junction ID	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.
X-Coordinate	The horizontal location of the junction on the map, measured in the map's scaling units. If left blank the junction will not appear on the network map.
Y-Coordinate	The vertical location of the junction on the map, measured in the map's scaling units. If left blank the junction will not appear on the network map.
Description	An optional text string that describes other significant information about the junction.
Tag	An optional text string used to assign the junction to a category, such as a pressure zone.
Elevation	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.
Base Demand	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.
Demand Pattern	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 demand remains constant at its base level.
Demand Categories	When the ellipsis button is clicked a Demand Category Editor is displayed that allows base demands and time patterns to be assigned to other categories of users at the junction.
Emitter Coeff.	Discharge coefficient for emitter (sprinkler or nozzle) placed at junction. Units are gpm/psi or lps/m. Leave blank if no emitter is present. See Emitters for more details.
Initial Quality	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.
Source Quality	When the ellipsis button is clicked a Source Quality Editor appears in which the quality of any water entering the network at this location can be specified.


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 scaling 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 scaling 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 used to assign the reservoir to a category, such as a pressure zone
Total Head	The piezometric head (elevation + pressure head) of water in the reservoir. This is a required property.
Head Pattern	The ID label of a time pattern used to model time variation in the reservoir's piezometric 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	When the ellipsis button is clicked a Source Quality Editor appears in which the quality of water entering the network at this location can be specified.


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	An optional text string that describes other significant information about the tank.
Tag	An optional text string used to assign the tank to a category, such as a pressure zone
Elevation	The elevation above a common datum in feet (meters) of the bottom shell of the tank. This is a required property.
Initial Level	The 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	The 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.
Maximum Level	The 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.
Diameter	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.
Minimum Volume	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).
Volume Curve	The ID label of a curve used to describe the relation between tank volume and water level. This property is useful for characterizing irregular-shaped tanks. If no value is supplied then the tank is assumed to be cylindrical.
Mixing Model	The type of water quality mixing that occurs within the tank. The choices include fully mixed (MIXED), two-compartment mixing (2COMP), first-in-first-out plug flow (FIFO), last-in-first-out plug flow (LIFO). See the Mixing Models topic for more information.
Mixing Fraction	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.
Reaction Coeff.	The bulk reaction coefficient for chemical reactions in the tank. Use a positive value for growth reactions and a negative value for decay. Leave blank if the Global Bulk reaction coefficient will apply. See Water Quality Reactions for more information.
Initial Quality	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.
Source Quality	When the ellipsis button is clicked a Source Quality Editor appears in which the quality of water entering the network from the tank can be specified (regardless of what the actual quality in the tank is).


Mixing Models

EPANET can use four different types of models to characterize mixing within storage tanks:

Complete Mixing

Two-Compartment Mixing

FIFO Plug Flow

LIFO Plug Flow


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 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 Coeff.	Unitless minor loss coefficient associated with bends, fittings, etc. Assumed 0 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 any flow in the pipe must be from the From node to the To node.
Bulk Coeff.	The bulk reaction coefficient for the pipe. Use a positive value for growth and a negative value for decay. Leave blank if the Global Bulk reaction coefficient will apply (see Reaction Options).  See Bulk Flow Reaction Rates  for further description of this parameter.
Wall Coeff.	The wall reaction coefficient for the pipe. Use a positive value for growth and a negative value for decay. Leave blank if the Global Wall reaction coefficient will apply (see Reaction Options). See Pipe Wall Reaction Rates for further description of this parameter.


Pump Properties

Property	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 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.
Effic. Curve	The ID label of the curve that represents the pump's wire-to-water efficiency (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 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 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 will be used.


Valve Properties

Property	Description
ID Label	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.
Start Node	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.
End Node	The ID of the node on the nominal downstream or discharge side of the valve. This is a required property.
Description	An optional text string that describes other significant information about the valve.
Tag	An optional text string used to assign the valve to a category, perhaps based on type or location.
Diameter	The valve diameter in inches (mm). This is a required property.
Type	The valve type (PRV, PSV, PBV, FCV, TCV, or GPV). See Valves for descriptions of the various types of valves. This is a required property.
Setting	A required parameter that describes the valve's operational setting. Valve Type      Setting Parameter PRV                 Pressure (psi or m) PSV                 Pressure (psi or m) PBV                 Pressure (psi or m) FCV                 Flow (flow units) TCV                 Loss Coeff. (unitless) GPV                ID of head loss curve
Loss Coeff.	Unitless minor loss coefficient that applies when the valve is completely opened. Assumed 0 if left blank.
Fixed Status	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.
NOTE:	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.


Setting Project Defaults

To set default values for a project:

1.	Select Project | Defaults.

2.	A Defaults dialog form will appear with three pages of default categories which you can edit:

Default ID Labels

Default Node/Link Properties

Default Hydraulic Options

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.


Viewing a Project Summary

To view a summary description of the current project:

1.	Select Project | Summary.

2.	A Project Summary dialog box will appear in which you can edit a descriptive title for the project as well as add notes that further describe the project.

3.	The dialog also displays certain network statistics, such as the number of junctions, pipes, pumps, etc.


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,

or the time of day.

They are text statements using one of the following three formats:

LINK linkID status IF NODE nodeID 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
nodeID	=	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 hours
clocktime	=	a 24-hour clock time

Some examples of simple controls are:

Control Statement	Meaning
LINK 12 CLOSED IF NODE 23 ABOVE 20	(Link 12 will be closed when the level in Tank 23 exceeds 20 ft.)
LINK 12 OPEN IF NODE 130 BELOW 30	(Link 12 will be opened if the pressure at Node 130 drops below 30 psi)
LINK PUMP02 1.5 AT TIME 16	(The relative speed of pump PUMP02 is set to 1.5 at 16 hours into the simulation)
LINK 12 CLOSED AT CLOCKTIME 10 AM LINK 12 OPEN AT CLOCKTIME 8 PM	(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:	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.


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. The use of rule-based controls is explained in the following topics:

Rule Format

Condition Clauses

Action Clauses

Example Rules

Rule Evaluation


Selecting a Map View

Use the Map Page of the Map Browser to select a node and link variable to view on the map. Variables are viewed on the map by using colors, as specified in the Map Legends, to display different ranges of values.

Node variables available for viewing include

Elevation

Base Demand (nominal or average demand)

Initial Quality (water quality at time zero)

*Actual Demand (actual demand at current time)

*Total Head

*Pressure

*Water Quality

Link variables available for viewing include:

Diameter

Roughness Coeff.

Bulk Reaction Coeff.

Wall Reaction Coeff.

*Flow Rate

*Velocity

*Head Loss (per 1000 feet (or meters) of pipe)

*Friction Factor (where H = f*(L/d)*v**2/2g)

*Reaction Rate (average over length of pipe)

*Water Quality (average over length of pipe)

The variables marked with asterisks are computed quantities whose values will only be available if a successful analysis has been run on the network (see Running an Analysis).


Setting the Map Scale

To set the map's scaling:

1.	Select View | Map Scale.

2.	Enter new scaling information into the Map Scale Dialog that appears.

3.	Click the OK button to re-scale the map.


Zooming the Map

To Zoom In on the map:

1.	Select View | Zoom In or click the [image] button 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:

1.	Select View | Zoom Out or click the [image] button 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.


Panning the Map

To pan the map across the Map window:

1.	Select View | Pan or click the [image] button 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:

1.	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.


Overview Map

The Overview Map, as pictured below, 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.


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	Allows selection of an object on the map
Select All	Selects all objects currently visible on the map
Group Select	Allows selection of a group of objects on the map
Group Edit	Edits a property for a selected group of objects


Project Menu

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

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


Running an Analysis

To run a hydraulic/water quality analysis:

1.	Select Project | Run Analysis or click the [image] button on the General 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 [image] 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.


Status Report

EPANET writes all error and warning messages generated during an analysis to a Status Report.

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 View | Report | Status.

The contents of the Status Report can be printed or copied to a file or to the Clipboard (see Printing and Copying).


Registering 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 registered first.

To register calibration data residing in a text file:

1.	Select Project | Calibration Data

2.	In the Calibration Data dialog box, 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 NotePad for editing.

5.	Repeat steps 2 - 4 for any other parameters that have calibration data.

6.	Click OK to accept your selections.


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 Adding Objects)

2.	Edit the properties of the objects that make up the system (see Editing Objects)

3.	Describe how the system is operated (see Curves, Time Patterns, and Controls)

4.	Select a set of analysis options (see Setting Analysis Options)

5.	Run a hydraulic/water quality analysis (see Running an Analysis)

6.	View the results of the analysis (see Viewing Results).


Adding an Object

  To add a node ...

  To add a link ...

  To add a map label ...

  To add a curve ...

  To add a time pattern ...

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 Importing a Partial Network).


Adding a Node

To add a Node using the Map Toolbar:

1.	Select the type of node (junction [image], reservoir [image], or tank [image] ) to add from the MapToolbar

2.	Move the mouse to the desired location on the map and click.

To add a Node using the Browser:

1.	Select the type of node (junction, reservoir, or tank) from the Object list of the Database Browser

2.	Click the Add button.

3.	Enter map coordinates with the Property Editor (optional).


Adding a map label

To add a label to the map:

1.	Select the [image] button 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:

1.	Select Curve from the Object list of the Database Browser.

2.	Click the Add button.

3.	Edit the curve using the Curve Editor.


Adding a time pattern

To add a time pattern to the network:

1.	Select Patterns from the Object list of the Database Browser.

2.	Click the Add button.

3.	Edit the pattern using the Pattern Editor.


Selecting an Object

To select an object on the map:

1.	Select Edit | Select or click the [image] button on the Map Toolbar.

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

To select an object using the Browser:

1.	Select the type of object from the Object listbox of the Database Browser.

2.	Select the desired object from the Item listbox.


Adding a link

To add a Link using the Map Toolbar:

1.	Select the type of link to add (pipe [image], pump [image], or valve [image] ) from the Map Toolbar

2.	Click the mouse over the link's start node

3.	Click the mouse again over the link's end node

To add a Link using the Browser:

1.	Select the type of link to add  (pipe, pump, or valve) from the Object list of the Database Browser

2.	Click the Add button.

3.	Enter the From and To nodes of the link in the Property Editor.


Editing an Object

To edit an object appearing on the map

select the object on the map, then click the Edit button on the Database Browser (or simply double-click the object on the map).

To edit an object appearing in the Browser

select the object from the Database Browser and then click the Edit button (or simply double-click the item in the Browser).


Map Legends

	Map Legends associate a color with a range of values for the current variable being viewed on the map. There are two legends - one for the network's nodes and another for its links.
  To display or hide a legend...

  To edit a legend ...

  To move a legend ...


Finding an Object

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

1.	Select View | Find or click the [image] button on the General Toolbar

2.	In the Map Finder dialog box that appears, select Node or Link and enter an ID label

3.	Click OK.

If the node/link exists it will be highlighted on the map and in the Browser. If the map is 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.


Map Display Options

To change the appearance of the network map:

Either

select View | Options when the Map window has focus,

-or-

click the [image] button on the General Toolbar when the Map window has focus,

-or-

right-click on any empty portion of the map.

A Map Display Options dialog box will appear with a page for each of the following display 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 labels on/of)

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

Arrows (selects visibility and style of flow direction arrows on links)

Notation (displays or hides node/link ID labels and view variable values)

Background (changes color of map's background)


Map Options - Nodes

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

Option	Description
Node Size	Selects node diameter
Proportional to Value	Select if node size should increase as node variable increases in value
Display Junctions	Displays junction nodes (all junctions will be hidden unless this option is checked).


Map Options - Links

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

Option	Description
Link Size	Sets thickness of links displayed on map
Proportional to Value	Select if link thickness should increase as link variable increases in value


Map Options - Labels

The Labels page of the Map Options dialog box controls how labels are displayed on the map.

Option	Description
Display Labels	Displays map labels (labels will be hidden unless this option is checked)
At Zoom Of	Selects minimum zoom at which labels should be displayed; labels will be hidden at zooms smaller than this


Map Options - Symbols

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

Option	Description
Display Tanks	Displays tank symbols
Display Pumps	Displays pump symbols
Display Valves	Displays valve 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


Map Options - Arrows

The Arrows page of the Map Options dialog box controls how flow direction arrows are displayed on the network map.

Option	Description
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:	When a link design variable (diameter, roughness, reaction coefficient) is viewed on the map, arrows show direction from the link's From-node to its To-node. When an output variable (flow, velocity, head loss, etc.) is viewed, arrows indicate the actual direction of flow.


Map Options - Notation

The Notation Page of the Map Options dialog box determines what kind of annotation is provided alongside of the nodes and links of the map.

Option	Description
Display Node IDs	Displays node ID labels
Display Node Values	Displays values of current node variable
Display Link IDs	Displays link ID labels
Display Link Values	Displays values of current link variable
At Zoom of	Selects minimum zoom at which notation should be displayed; all notation will be hidden at zooms smaller than this


Map Options - Background

The Background page of the Map Options dialog box is used to select a choice of background color for the network map.


Deleting an Object

To delete an object:

1.	Select the object on the map or from the Database Browser.

2.	Either:

A.	click the [image] button on the General Toolbar,

B.	click the Del button on the Database Browser,

C.	press the Del key.

Note:	You can require that all deletions be confirmed before they take effect. See the General Preferences page of the Program Preferences dialog box.


Moving an Object

To move a node or label to another location on the map:

1.	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.


Selecting a Group of Objects

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

1.	Select Edit | Group Select or click the [image] button 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.

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.)

See also:

Editing a Group of Objects


Editing a Group of Objects

To edit a property for a group of objects:

1.	Draw a polygon region around the group of objects to be edited if one does not already exist (see Selecting a Group of Objects) or select Edit | Select All to select all object currently in view on the map.

2.	Select Edit | Group Edit.

3.	Define what to edit in the Group Edit Dialog Box that appears:


Viewing Results on the Map

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

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

2.	When the Flyover Map Labeling program preference is selected, moving the mouse over any node or link will display its ID label and the value of the current view variable for that node or link in a hint-style box.

3.	ID labels and view variable 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 box.

4.	Nodes or links meeting a specific criterion can be identified by submitting a Map Query.

5.	You can animate the display of results on the network map either forward or backward in time by using the [image] and [image] buttons on the Browser. The [image] button stops the animation while the button [image] returns you to time zero. Animation is only available when a node or link view variable is a computed value (e.g., link flow rate can be animated but diameter cannot).

6.	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.).

To submit a map query:

1.	Select a time period in which to query the map from the Map Browser.

2.	Select View | Query or click the [image] button on the Map Toolbar.

3.	Fill in the following information in the Query dialog box that appears:

Item	Action
Object	Select Nodes or Links
Variable	Select a variable to compare against
Relation	Select Above, Below, or Equals
Value	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.


Viewing Results with a Graph

Analysis results, as well as some database variables, can be viewed using several different types of graphs. Graphs can be printed, copied to the Windows clipboard, or saved as data file or Windows metafile.

Types of graphs

Creating a graph

Customizing a graph


Types of Graphs

The following types of graphs can be used to view values for a selected variable:

Type of Plot	Description	Applies To
Time Series Plot	Plots value versus time	Specific nodes or links over all time periods
Profile Plot	Plots value versus distance	A list of nodes at a specific time
Contour Plot	Shows regions of the map with equal values	All nodes at a specific time
Frequency Plot	Plots value versus fraction of objects not exceeding the value	All nodes or links at a specific time
System Flow	Plots total system production and consumption flow versus 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, and Calibration Data have been registered for that node or link, the graph will also display any observed values of the variable being plotted that have been supplied with the Calibration Data


Creating a Graph

To create a graph:

1.	Select View | Graph or click the [image] button on the General Toolbar.

2.	Fill in the choices on the Graph Selection Dialog box that appears:

3.	Click OK to create the graph.


Water Age
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.


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 storage nodes.  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 over time.


Water Quality Reactions

The water quality module of 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. Bulk fluid reactions can also occur within tanks. EPANET allows a modeler to use different reaction rates for the two zones of reaction.

Bulk Flow Reaction Rates

Pipe Wall Reaction Rates


Customizing a Graph

To customize the appearance of a graph:

1.	Make the graph the active window (click on its title bar).

2.	Select View | Options, or click the [image] button on the General Toolbar, or right-click on the graph.

3.	For a Time Series, Profile, or Frequency plot use the resulting  Graph Options dialog box to customize the graph's appearance.

4.	For a Contour plot use the resulting Contour Options dialog box 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.


Viewing Results with a Table

EPANET allows you to view selected database 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.

Creating a table

Modifying a table


Selecting Items to Graph

Time Series plots and Profile plots require one or more objects be selected for plotting. To select items into the Graph Selection Dialog box for plotting:

1.	Select the object (node or link) either on the Network Map or on the Database Browser. (The Graph Selection Dialog box will remain visible during this process).

2.	Click the Add button on the Graph Selection Dialog to add the selected item to the list.

3.	Another way to add items to a graph is to minimize the Graph Selection Dialog box, select the object as in Step 1, and then drag the object label from the Browser onto the title bar of the minimized dialog box. The advantage of this method is that it avoids having the Graph Selection Dialog box hide a large portion of the network map from view.

The other buttons on the Graph Selection dialog form are used as follows:

Button	Purpose
Load (Profile Plot Only)	Loads a previously saved list of nodes
Save (Profile Plot Only)	Saves current list of nodes to file
Delete	Deletes selected item from list
Move Up	Moves selected item on list up one position
Move Down	Moves selected item on list down one position


Frequently Asked Questions

1.	How can I import a pipe network created from a CAD or GIS program?

2.	How do I model a groundwater pumping well?

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

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

5.	How can I compute fire flows (maximum flow available from a node at a specific pressure)?

6.	How do I model a reduced pressure backflow prevention valve?

7.	How do I model a pressurized pneumatic tank?

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

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

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

11.	How can I model a chlorine booster station?

12.	How would I model THM growth in a network?

13.	Can I run multiple EPANET sessions at the same time?


Demand Editor

The Demand Editor is used to assign base demands and time patterns to additional categories of water users at a junction. The editor is invoked when the junction appears in the Property Editor by clicking the ellipsis button (or hitting the Enter key) when the Demand Editor 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)

The table initially is sized for 6 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.


Legend Editor

The Legend Editor (pictured below) is used to set numerical ranges to which different colors are assigned for viewing a particular variable on the network map.

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 variable 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 Default Colors button is used to restore the original default colors to a legend.

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).


Editing a Time Pattern

To edit a time pattern:

1.	Select the pattern to edit from the Database Browser.

2.	Click the Browser's Edit button.

3.	Edit the pattern's properties in the Pattern Editor.


Editing a Curve

To edit a curve:

1.	Select the curve to edit from the Database Browser.

2.	Click the Browser's Edit button.

3.	Edit the curve's properties in the Curve Editor.


Roughness Coefficient
Roughness Coefficients for New Pipe

Material	Hazen-Williams C (unitless)	Darcy-Weisbach ε(millifeet)	Manning's n (unitless)
Cast Iron	130 - 140	0.85	0.012 - 0.015
Concrete or Concrete Lined	120 - 140	1.0 - 10	0.012 - 0.017
Galvanized Iron	120	0.5	0.015 - 0.017
Plastic	140 - 150	0.005	0.011 - 0.015
Steel	140 - 150	0.15	0.015 - 0.017
Vitrified Clay	110		0.013 - 0.015


Setting Analysis Options

To set Analysis Options:

1.	Select Options from the Object list of the Database Browser.

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

3.	If the Property Editor is not already visible, click the Edit button.

4.	Edit your option choices in the Property Editor.


Editing Controls

To edit either Simple or Rule-Based Controls:

1.	Select Controls from the Object list of the Database Browser.

2.	Select Simple or Rule-Based from the Item list.

3.	Click the Edit button.

4.	Type and edit your control statements in the Controls Editor dialog box that appears.

5.	Click the Editor's OK button to save your edits.

See Also:

Controls


Rule Format

Rule-based Controls are statements of the form:

RULE ruleID

IF  condition_1

AND condition_2

OR  condition_3

AND condition_4

etc.

THEN action_1

AND  action_2

etc.

ELSE action_3

AND  action_4

etc.

PRIORITY priority

where

ruleID	=	an ID label assigned to the rule

conditon_n	=	a condition clause

action_n	=	an action clause

priority	=	a priority value (e.g., a number from 1 to 5)

The following conventions apply to rule statements:

1.	Only the RULE, IF and THEN portions of a rule are required; the other portions are optional.

2.	Any number and combination of AND and OR clauses can be used in a rule.

3.	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 ...

4.	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.

5.	There is no limit on the number of rule statements that can be added to a project.


Rule Condition Clauses

A condition clause in a Rule-Based Control takes the form of:

object id attribute relation value

where

object	=	a category of network object
id	=	the object's ID label
attribute	=	an attribute or property of the object
relation	=	a relational operator
value	=	an attribute value

Some example conditional clauses are:

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)

CLOCKTIME (24-hour clock time with AM or PM appended)

Relation operators consist of the following:

=	IS

<>	NOT

<	BELOW

>	ABOVE

<=	>=


Rule Action Clauses

An action clause in a Rule-Based Control takes the form of:

object id STATUS/SETTING IS value

where

object	=	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


Rule Examples

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


Rule Evaluation

Rule-Based Controls are implemented during the hydraulic analysis portion of a simulation as follows:

1.	Controls are evaluated at a sub-hydraulic time step equal to 1/10 of the normal hydraulic time step (e.g., if hydraulics are updated every hour, then rules are evaluated every 6 minutes).

2.	Over this sub-hydraulic time step, clock time is updated as are the water levels in storage tanks (based on the last set of pipe flows computed).

3.	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.

4.	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.

5.	The action list is cleared and the next sub-hydraulic time step is checked.


Constant Energy Pump

A constant energy pump is a pump that operates at a constant horsepower or kilowatt rating over all combinations of flow and head.


Single-Point Pump Curve
	A single-point pump curve is defined by a single head-flow combination that represents a pump's desired operating point. EPANET fills in the rest of the curve by assuming: a shutoff head at zero flow equal to 133% of the design head a maximum flow at zero head equal to twice the design flow.


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


Multi-Point Pump 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.


Graph Options Dialog Box

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

1.	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.


Contour Options Dialog Box

The Contour Options dialog box controls the appearance of a contour plot.

Option	Description
Legend
Display Legend	Toggles display of legend on/off
Modify Legend	Changes colors and contour intervals
Network Backdrop
Foreground	Color of network image displayed on plot
Background	Background color used for line contour plot
Link Size	Thickness of lines used to display network
Style
Filled Contours	Plot uses colored area-filled contours
Line Contours	Plot uses colored line contours
Contour Lines
Thickness	Thickness of lines used for contour intervals
Lines per Level	Number of sub-contours per major contour level
Default	Saves choices as defaults for next contour plot


Curve Editor

The Curve Editor edits the properties of a curve object. To use the Curve Editor:

1.	Enter values for the following dialog items:

Item	Description
Curve ID	ID label of the curve (maximum of 15 characters)
Description	Optional description of what the curve represents
Curve Type	Type of curve
X-Y Data	X-Y data points for the curve
2.	As you move between cells in the X-Y data table (or press the Enter key) the curve is redrawn in the preview window.

3.	Press OK to accept the curve.


Pattern Editor

The Pattern Editor edits the properties of a time pattern object. To use the Pattern Editor:

1.	Enter a pattern ID label of 15 or less characters in the Pattern ID field

2.	Enter an optional description of the pattern in the Description field

3.	Enter multipliers for each time period of the pattern. The length of the time period is supplied as one of the project's Time Options. Its current value is displayed on the preview chart.

4.	As multipliers are entered the preview chart is redrawn to provide a visual depiction of the pattern.

5.	Click the OK button to accept the pattern.


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.

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:

Single-Point Curve

Three-Point Curve

Multi-Point Curve

For variable speed pumps, the pump curve shifts as the speed changes. The relationships between flow (Q) and head (H)  at speeds N1 and N2 are

EPANET will shut a pump down if the system demands a head higher than the first point on the curve (i.e., the shutoff head).

A pump curve must be supplied for each pump in the system unless the pump is a constant energy pump.


Efficiency Curve

An Efficiency Curve determines pump efficiency (Y in percent) as a function of pump flow rate (X in flow units). Efficiency should represent wire-to-water efficiency which 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, then the global pump efficiency (a single number) in the project's Energy Options is used instead.


Volume 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.


Head Loss Curve

A Head Loss Curve is used to described the head loss (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 head loss - flow relationships, such as reduced flow backflow prevention valves, turbines, and well drawdown behavior.


Complete Mixing

	This mixing  model 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.


Two-Compartment Mixing

This mixing model divides the available storage volume in a tank into two compartments, both of which are assumed to be completely mixed. The inlet/outlet pipes of the tank are assumed to be located in the first 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 volume devoted to the first compartment.


FIFO Plug Flow
First-In-First-Out (FIFO) Plug Flow

	This mixing model 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.


LIFO Plug Flow
Last-In-First-Out (LIFO) Plug Flow

	This mixing model 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. Physically speaking this type of model might apply to a tall, narrow standpipe with an inlet/outlet pipe at the bottom and a low momentum discharge. It requires no additional parameters be provided.


Source Quality Editor

The Source Quality Editor is a pop-up dialog box 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 box contains the following fields:

Field	Description
Source Type	Select either Concentration or Mass Injection - see note below
Source Quality	Baseline or average concentration/mass flow rate 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
Source quality can be specified either in terms of concentration or mass injection rate (in mass units per minute, where mass units depend on the units being used for concentration - either milligrams or micrograms).

The way in which a concentration source is handled at a junction node depends on the type of demand exerted at the node:

If the net demand is negative, meaning that water is entering the network, then the source flow enters with the specified concentration and mixes with any other flows brought into the junction from connecting links.

If the net demand is zero or positive, then the concentration source acts like a satellite booster facility. Water leaving the node through connecting links will have a quality equal to the source quality as long as the quality entering the node from connecting links is less than this value. If the water entering the node from the network has a higher concentration than the source then the effect of the source is ignored.


Minor Losses

Minor head losses (also called local losses) can be associated with the added turbulence that occurs at bends, junctions, meters, and valves. The importance of such losses will depend on the layout of the pipe network and the degree of accuracy required.  Minor losses are proportional to the velocity head of water flowing through a pipe or valve. The proportionality constant is termed the "loss coefficient" and its value depends on the geometry and type of fitting.


Pressure Reducing Valve

A Pressure Reducing Valve (PRV) is used to limit the pressure at a point in the pipe network. The valve can be in one of three states:

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).


Pressure Sustaining Valve

A Pressure Sustaining Valve (PSV) is used to maintain a set pressure at a specific point in the pipe network. The valve can be in one of three states:

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

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


Pressure Breaker Valve

A Pressure Breaker Valve (PBV) forces a specified pressure loss to occur across the valve. Flow through the valve can be in either direction. PBV's are not true physical devices but can be used to model situations where a particular pressure drop is known to exist.


Flow Control Valve

A Flow Control Valve (FCV) limits the flow through itself 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).


Throttle Control Valve

A Throttle Control Valve (TCV) simulates 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.


General Purpose Valve

A General Purpose Valve (GPV) provides the capability to model devices and situations with unique head loss - flow relationships, such as reduced pressure backflow prevention valves, turbines, and well drawdown behavior. The valve setting is the ID of a Head Loss Curve.


Graph Options - General

The following options can be set on the General page of the Graph Options dialog box:

Option	Description
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


Graph Options - Axes

The Horizontal Axis and Vertical Axis pages of the Graph Options dialog box adjust the way that the axes are drawn on a graph.

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


Graph Options - Legend

The Legend page of the Graph Options dialog box controls how the legend is displayed on the graph.

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.


Graph Options - Series

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

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

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

3.	Click the Font button to change the font used for the legend.

(Other legend properties are selected on the Legend page of the dialog.)

4.	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.)


Graph Options - Series - Lines

Option	Description
Style	Selects line style.
Color	Selects line color.
Size	Selects line thickness (applies only to solid line style).
Visible	Determines if line is visible.


Graph Options - Series - Markers

Option	Description
Style	Selects marker style.
Color	Selects marker color.
Size	Selects marker size.
Visible	Determines if marker is visible.


Graph Options - Series - Patterns

Option	Description
Style	Selects pattern style.
Color	Selects pattern color.
Stacking	Not used with any of the graph types generated by EPANET.


Graph Options - Series - Labels

Option	Description
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 or not.
Visible	Determines if labels are visible or not.


Troubleshooting Results

EPANET will issue specific Error and Warning messages when problems are encountered in running a hydraulic/water quality analysis. The most common problems are:

Pumps cannot deliver head or flow

Network is disconnected

Negative pressures exist

System unbalanced

Hydraulic equations cannot be solved


Pump Problems

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.


Disconnected Network

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 a demand node is not connected by a path of open links to a reservoir or tank. 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 flow and energy 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 over time.


Negative Pressures

EPANET will issue a warning message when it encounters negative pressures after a hydraulic analysis has been made. 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 keep shutting on and off.

The project's Hydraulic Options offer two ways to handle System Unbalanced conditions. 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 possible 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.


Hydraulic Equations Unsolveable
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 there is a portion of the system that 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.


Table Options Dialog Box

The Table Options dialog box is used to create a tabular display of a network's database and computed results. The dialog has three tabbed pages as follows:

Type

Columns

Filters

All three pages are available when the table is first being created. After the table is created, only the Columns and Filters tabs will appear.


Table Options - Type

The Type page of the Table Options Dialog Box 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.


Table Options - Columns

The Columns page of the Table Options dialog box selects the columns that are displayed in a table.

Click the checkbox next to the name of each variable you wish to include in the table, or if the variable is already selected, click in the box to unselect it (the keyboard's spacebar can be used in lieu of clicking the mouse).

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


Table Options - Filters

The Filters page of the Table Options dialog box is used to define criteria 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 criterion (e.g., Pressure Above 50)

Click the Add button to add the criterion to the list

Use the Delete button to remove a selected criterion from the list

Multiple criteria used to filter the table are connected by AND's.


Viewing a Report

EPANET can create a variety of specialized reports. These include:

Status Report

Energy Report

Calibration Report

Reaction 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.

To generate an Energy Report select View | Report | Energy.


Calibration Report

A Calibration Report can show how well EPANET's simulated results match measurements taken from the system being modeled.

Creating a Calibration Report

Viewing a Calibration Report

Note: 	Calibration data must be registered with the project before a Calibration Report can be generated (see Registering Calibration Data).


Calibration Report - Statistics

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.

The statistics listed for each measurement location and the network as a whole 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)

In addition the following overall statistics are also provided:

Correlation between means (correlation coefficient between the mean observed value and mean simulated value at each location)

Measurement Error (percent error in the method used to measure the variable being reported on as supplied in the Calibration Report Options)

Degrees of Freedom (number of non-zero observations)

Chi-Squared Statistic (sum of squared errors divided by square of measurement error)

Chi-Squared Probability (measure of goodness of fit between model and data).

The higher the Chi-Squared probability, the better is the fit between the model and the data. Models with probabilities above 0.001 are usually deemed acceptable. Increasing the value of the measurement error will push up the Chi-Squared probability.


Calibration Report - Correlation Plot

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.


Calibration Report - Mean Comparisons

The Mean Comparisons page of a Calibration Report presents a bar chart that compares the mean observed and mean simulated value for a calibration variable 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 View | Options or by clicking the [image] button on the General Toolbar, or by right-clicking anywhere on the chart.


Selecting a Printer

To select a printer from among your installed Windows printers and set its properties:

1.	Select File | Page Setup.

2.	Click the Printer button on the Page Setup dialog that appears

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.


Setting the Page Format

To format the printed page:

1.	Select File | Page Setup.

2.	Enter values for the left, right, top, and bottom margins in the appropriate fields of the Page Setup dialog box that appears.

3.	A desired paper size and paper orientation (Portrait or Landscape) can also be chosen from the dialog box.

4.	Click OK to accept your choices.


Print Preview

To preview a printout:

Select File | Print Preview.

A Preview form will appear which shows how each page of the object being printed will appear when printed.


Printing the Current View

To print the current object being viewed:

Select File | Print or click the [image] button on the General Toolbar.

The following objects can be printed:

Database Browser (properties of the currently selected object)

Network Map (at the current zoom level)

Graphs (Time Series, Profile, Contour, and Frequency plots)

Tables (Network and Time Series tables)

Reports (Status, Energy, Calibration, and Reaction)


Importing a Scenario

To import a project scenario from a file:

1.	Select File | Import | Scenario.

2.	Use the File Open dialog box that appears to select a scenario file to import. Use the dialog's Preview window to view the initial contents of files as they are selected.

3.	Click the OK button to accept your selection.

The data contained in the scenario file will replace that in the current project.


Exporting a Scenario

To export a project scenario to a text file:

1.	Select File | Export | Scenario.

2.	In the Export Scenario dialog box that appears select the types of data that you wish to save.

3.	Enter a 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 appears enter a name for the file under which your scenario should be saved.

6.	Click OK to complete the export

The exported scenario can be imported back into the project at a later time (see Importing a Scenario).


Exporting the Map

The current view of the network map can be saved to file using either Autodesk's DXF (Drawing Exchange Format) format or the Windows metafile (WMF) format. The DXF format is readable by many Computer Aided Design (CAD) programs. Metafiles can be inserted into word 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 to a DXF or metafile:

1.	Select File | Export | Map.

2.	In the Save As dialog box that appears, use the Save as Type combo box to select either DXF file or WMF file.

3.	Enter a name for the file and click OK to save the map or Cancel to cancel the save.


Modeling Additions

1.	A new input file format (.NET file) has been introduced to work more efficiently with the new user interface. This is a binary file that the user does not edit directly. The old Version 1.1-style text files (.INP files) can still be opened and written to (mainly to provide a readable hardcopy of a network's input data).

2.	The ID's used to identify network objects no longer have to be numbers - they can contain any combination of up to 15 letters and numerals.

3.	A new Reservoir category of object has been added to distinguish reservoirs from storage tanks. A time pattern can be assigned to the reservoir elevation (or head) to simulate time variation in boundary conditions. See Reservoirs for more details.

4.	A new Curve object has been added to model relationships between two variables  (see Curves).

5.	Pumps have been updated to allow the use of multi-point, user-defined pump curves and to assign time patterns to control a pump's status or speed (see Pump Properties).

6.	Computation of pumping energy and cost has been added. One can either use pump-specific efficiency curves and electricity rate schedules for these computations (see Pump Properties) or a set of default values (see Energy Options).

7.	Non-cylindrical storage tanks can be modeled by specifying a volume versus water level curve for the tank (see Volume Curve and Tank Properties).

8.	Multiple demand categories ( base demand plus time pattern) can now be assigned to junctions (see Junction Properties and Demand Editor).

9.	Old-style control statements are now called Simple Controls and have been extended to allow a link to be controlled based on the time of day (see Simple Controls).

10.	A new category of controls, called Rule-Based controls, allows the control of links to be based on a combination of conditions  (see Rule-Based Controls).

11.	The ability to model emitters (sprinklers or orifices) placed at junctions has been added. With these devices the outflow from the junction becomes a function of the pressure available. (See Junction Properties and Emitters).

12.	A General Purpose Valve has been introduced to model a link which obeys a user-defined curve of head loss versus flow instead of one of the standard head loss formulas (see Valves and Head Loss Curve).

13.	Improved options for dealing with disconnected and hydraulically unbalanced conditions have been added (see Troubleshooting Analysis Results).

14.	The water quality solver has been replaced with a more efficient Lagrangian Time Driven method. The key user-supplied parameters for this method are the Water Quality Time Step (see Time Options) and the Quality Tolerance (see Quality Options).

15.	Water quality sources can now be defined in terms of mass inflow rate in addition to concentration level (see Source Quality Editor).

16.	Bulk flow reactions can now be modeled with n-th order kinetics.

17.	Pipe wall reactions can be modeled with either zero- or first-order kinetics.

18.	A water quality constituent's growth or decay can be modeled up to a limiting potential (see Water Quality Reactions).

19.	Pipe wall reaction coefficients can be correlated to pipe roughness coefficients (see Wall Reaction - Pipe Roughness Correlation).

20.	Several different models are available for characterizing mixing in storage tanks (see Mixing Models).

21.	Extended period simulation results can be displayed as a single set of time-averaged values for each node and link in the network (see Time Options).

22.	Calibration statistics can be computed showing how well simulated values compare with measured ones (see Calibration Report).


Group Edit Dialog Box

The Group Edit dialog box is used to modify a property for a selected group of objects (see Selecting a Group of Objects). To use the dialog box:

1.	Select a type of object (Junctions or Pipes) to edit.

2.	Check the "with" box to add a filter that will limit the objects selected for editing. Select a property and value that define the filter. An example might be "with Diameter equal to 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.


Map Label Properties

Map Labels have the following properties that can be edited in the Property Editor:

Property	Description
Text	The label's text.
X-Coordinate	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 below). Leave blank if label will not be anchored.
Font	Launches a Font dialog that allows selection of the label's font, size, and style.
NOTE:	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 on 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.


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)
List of Open Windows	Lists all open windows; selected window currently has focus


Calibration File

A Calibration File is a text file that contains measured data for a particular variable taken over a particular period of time within a distribution system. The file is used to provide observed data against which the results of a network simulation can be compared. Separate files should be created for different variables (e.g., pressure, fluoride, chlorine, flow) and different sampling studies.

Each line of the file contains the following items:

Item	Description
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 entered as either a decimal number (e.g., 27.5) or in hrs:min format (e.g., 27:30). For data taken 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 as shown below:

;Fluoride Tracer Measurements

;Location    Time    Value

;--------------------------

   N1         0       0.5

              6.4     1.2

             12.7     0.9

   N2         0.5     0.72

              5.6     0.77


Graph Selection Dialog Box

The Graph Selection Dialog Box is used to select a type of graph and its contents to display. The choices available in the dialog box consist of the following

Choice	Description
Graph Type	Select a graph type
Variable	Select a variable to graph
Time Period	Select a time period to graph (does not apply to Time Series plots)
Object Type	Select either Nodes or Links (only Nodes can be graphed on Profile and Contour plots)
Items to Graph	Select items to graph (applies only to Time Series and Profile plots) -- see Selecting Items to Graph


Map Scale Dialog Box

The Map Scale dialog box is used to change the scaling used for the Network Map.

Item	Description
Lower Left Coordinates	The X,Y coordinates of the lower left point on the map
Upper Right Coordinates	The X,Y coordinates of the upper right point on the map
Distance Units	Units used to measure distances on the map. The choices are: Feet Meters Decimal Degrees User Units


User Interface Enhancements

1.	A Visual Editing system has been implemented for using point-and-click methods to add and modify system elements directly on the network map.

2.	Special editors have also been provided for entering data for node/link properties, junction demands, time pattern factors, pump and other curves, control rules, and analysis options.

3.	A Group Editing feature has been added which allows the user to select objects within an irregular shaped portion of the network and apply such editing operations as "For all pipes with Tag equal to CLASS-A replace roughness with 110."

4.	A Flyover Map Labeling feature is available that displays a node or link's ID label and current property value whenever the mouse is placed over it.

5.	A Map Query function can be called on to highlight those nodes or links on the map that meet a specific user-defined criterion (e.g., it will show all nodes where the pressure is below 20 psi and hide the rest).

6.	Enhanced map display options are available including the ability to make node or link size be proportional to property value and to hide symbol, flow arrow and notation display until a certain map scale is zoomed in to.

7.	The map display can be animated to move either forward or backward in time at a user-adjustable speed.

8.	Energy Reports can be generated that compare energy consumption and cost between all pumps in the system.

9.	A Reaction Report can be generated that shows what fraction of network-wide water quality reactions occur in the bulk flow, at the pipe wall, and in storage tanks.

10.	Calibration Reports can be produced that statistically evaluate a model's goodness of fit to measured data.

11.	Profile, Frequency and System Flow plots have been added to Time Series and Contour plots for graphical display of simulation results.

12.	Multiple nodes or links can be plotted on the same time series graph.

13.	An enhanced set of formatting options is available to make graphs of publication quality.

14.	The tabular display of results has been enhanced by allowing the user to choose which variables should appear in a table, which variable should be sorted on, and how the table entries should be filtered with respect to one or more conditions.

15.	The number of decimal places displayed for each computed variable can be set by the user.

16.	The current set of reports, graphs, and tables being displayed are updated automatically after a new network analysis is made.

17.	The network map can be saved to disk as a DXF file, a Windows metafile, or as an ASCII text file (node coordinates and property values).

18.	Graphs can be saved to file or copied to the clipboard as bitmaps, metafiles, or ASCII data.

19.	Page setup and print preview functions have been added.

20.	Different data scenarios (demands, initial quality, pipe roughness, reaction coefficients, system controls) can be saved from and read in to a project.


Displaying a Legend
To display/hide a node (link) legend:

select/unselect View | Node Legend | Show  (View | Link Legend | Show)

-or-

right-click on an empty portion of the Network Map and click Node Legend (Link Legend) from the pop up menu.


Editing a Legend
To edit a node (link) legend:

1.	Either select View | Node Legend | Modify (View | Link Legend | Modify) or right-click on the legend if it is visible.

2.	Use the Legend Editor dialog form that appears to modify the legend's colors and intervals.


Moving a Legend
To move a legend to another location:

1.	Press the left mouse button over an empty area of the legend

2.	With the button held down, drag the legend to its new location and release the button.


Controls Editor

The Controls Editor is a text editor window used to edit Controls statements. 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.

See Also:

Simple Controls

Rule-Based Controls


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) at all nodes

Initial water quality at all nodes

Roughness coefficients for all pipes

Reaction coefficients (bulk and wall) for all pipes

Simple and rule-based controls

EPANET has the facility to 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 modified outside of EPANET using a text editor or spreadsheet program.


Emitters

Emitters are devices associated with junctions that model the flow through a nozzle or orifice. In these situations the demand (i.e. the flow rate through the emitter) varies in proportion to the square root of the pressure at the junction. The constant of proportionality is termed the "discharge coefficient". For nozzles and sprinkler heads the manufacturer usually provides the value of the discharge coefficient in units of gpm/psi (flow through the device at a 1 psi pressure drop).

Emitters are needed 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 for the leaking crack or joint can be estimated) and 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., 10000) and modify the junction's elevation to include the head equivalent of the pressure target.

When both an emitter and a normal demand are specified for a junction, the demand that EPANET reports in its output results includes both the normal demand and the flow through the emitter.


Units
Units of Measurement

NOTE: US Customary units apply when CFS, GPM, or MGD are chosen as flow units. SI Metric units apply when flow units are LPS.

Parameter	US Customary	SI Metric
Concentration	mg/L or ug / L	mg/L or ug / L
Demand	CFS, GPM, or MGD	LPS
Diameter (Pipes)	inches	millimeters
Diameter (Tanks)	feet	meters
Efficiency	percent	percent
Elevation	feet	meters
Emitter Coeff.	GPM per psi	LPS per meter
Energy	kwatt - hours	kwatt - hours
Flow	CFS, GPM, or MGD	LPS
Friction Factor	unitless	unitless
Head	feet	meters
Length	feet	meters
Minor Loss Coeff.	unitless	unitless
Power	horsepower	kwatts
Pressure	psi	meters
Reaction Coeff. (Bulk)	1/day (1st-order)	1/day (1st-order)
Reaction Coeff. (Wall)	mass/L/day (0-order) ft/day (1st-order)	mass/L/day (0-order) meters/day (1st-order)
Roughness Coeff.	millifeet (D-W) unitless otherwise	mm (D-W) unitless otherwise
Source Mass Injection	mass/minute	mass/minute
Velocity	ft/sec	meters/sec
Volume	cubic feet	cubic meters
Water Age	hours	hours


Minor Loss Coefficients

Globe valve, fully open	10.0
Angle valve, fully open	5.0
Swing check valve, fully open	2.5
Gate valve, fully open	0.2
Short-radius elbow	0.9
Medium-radius elbow	0.8
Long-radius elbow	0.6
45 degree elbow	0.4
Closed return bend	2.2
Standard tee - flow through run	0.6
Standard tee - flow through branch	1.8
Square entrance	0.5
Exit	1.0


Hazen-Williams Formula
Hazen-Williams Head Loss Formula

where:

HL	=	head loss in feet
Q	=	flow in cfs
L	=	pipe length in feet
d	=	pipe diameter in feet
C	=	Roughness coefficient (Hazen-WIlliams C-factor)


Darcy-Weisbach Formula

where:

HL	=	head loss in feet
g	=	acceleration of gravity in ft/sec/sec
L	=	pipe length in feet
d	=	pipe diameter in feet
v	=	flow velocity in ft/sec
f	=	friction factor (unitless)
The friction factor is a function of (ε/d) and the Reynolds number, where ε is a relative roughness coefficient with units of length. The above formula can be used with any consistent set of units.


Chezy-Manning Formula

where

HL	=	head loss in feet
Q	=	flow in cfs
L	=	pipe length in feet
d	=	pipe diameter in feet
n	=	Manning roughness coefficient


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 detected in the input data (see below).
201	Syntax error in a line of the input file created from your network data.
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.
208	Reference made to an undefined node.
209	An illegal value was assigned to a node property.
210	Reference made to an undefined link.
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.
214	Too many characters in a line read from file.
215	Two or more nodes or links share the same ID label.
216	Energy data supplied for an undefined pump.
217	Invalid energy data supplied for a pump.
218	Attempt to connect two tanks or reservoirs together.
219	Misplaced clause in a control rule.
220	Not enough nodes in the network to analyze.
221	There is not at least one tank or reservoir in the network.
222	More than one node with the same ID.
223	More than one link with the same ID.
224	More than one curve with the same ID.
225	Invalid lower/upper levels specified for a tank.
226	No pump curve or power rating was supplied for a pump.
227	Pump has an invalid pump curve.
228	A valve is illegally connected to a tank or reservoir.
229	A valve is illegally connected to another valve.
230	A curve has non-increasing X-values.
231	A volume curve has non-increasing Y-values.
232	A pump curve has non-decreasing head values.
233	A node is not connected to any links.
234	Report start time is greater than the simulation duration.
235	A water quality source refers to an undefined node
302	System cannot open the temporary input file.
303	System cannot open the status report file.
304	System cannot open binary output file.
308	Could not save results to file.
309	Could not write results to report file.


Exporting to Text File

To export a project's data  to a text file:

1.	Select File | Export | Network.

2.	In the Save dialog box 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 for analysis at a another time by using either the File | Open or File | Import | Network commands.

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 by using the File | Save or File | Save As commands.


Copying To

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:

1.	Select Edit | Copy To or click the [image] button.

2.	Select choices from the Copy Dialog box that appears and click OK

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

See Also:

Copying and Pasting Objects


Copy Dialog

The Copy Dialog box appears when the Edit | Copy To command is selected. To use the dialog box:

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

2.	Select what format to copy in. The choices are:

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.


Importing a Network Map

To import the coordinates for a network map stored in a text file:

1.	Select File | Import | Map.

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.


Copying and Pasting Objects
Copying and Pasting Object Properties

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:

1.	Right-click the object on the map.

2.	Select Copy from the pop-up menu that appears.

To paste copied properties into an object:

1.	Right-click the object on the map.

2.	Select Paste from the pop-up menu that appears.


What's New
What's New in Version 2

Modeling Additions

User Interface Enhancements


Database Browser

The Database Browser (shown below) is accessed from the Database tab on the Browser window. It provides functions for navigating, adding, deleting, and editing the various objects in an EPANET database.

The Database Browser contains the following controls:

Control	Purpose
Object	Selects an object category
Item	Selects a particular item
Add	Add a new item to the database
Del	Deletes the selected item
Edit	Edits the properties of the selected item


Map Browser

The Map Browser (shown below) is accessed from the Map tab of the Browser Window. It controls which variables and time period are viewed on the Network Map. It also contains controls for animating the map through time.

The Map Browser contains the following controls:

Control	Purpose
Nodes Combo Box	Selects a node variable for viewing
Links Combo Box	Selects a link variable for viewing
Time Combo Box and Scroll Bar	Selects a time period for viewing
Push Buttons	Controls automatic map redisplay as time moves forward or backward (i.e., animation)
Slider Bar	Sets animation speed
The animation control push buttons work as follows:

	Rewind (return to time 0)
	Animate back through time
	Stop the animation
	Animate forward in time


Help Menu

The Help Menu contains commands for getting help in using EPANET.

Command	Description
Help Topics	Displays the Help system's Help Topics dialog box
Units	Lists the units of measurement for all EPANET parameters
About	Lists information about the version of EPANET being used


Creating a Calibration Report

To create a Calibration Report:

1.	First make sure that Calibration Data for the variable being calibrated has been registered with the project (see Registering Calibration Data).

2.	Select View | Report | Calibration.

3.	In the Calibration Report Options form that appears

select a variable to calibrate against

select the measurement locations to use in the report

supply a relative measurement error (standard deviation of measurement method as a percent of the mean) or set to zero if not known

4.	Click OK to create the report.

After the report is created the The Calibration Report Options form can be recalled to change report options by selecting View | Options or by clicking the [image] button on the General Toolbar.


Viewing a Calibration Report

The Calibration Report contains three tabbed pages with the following information on each:

Statistics

Correlation Plot

Mean Comparisons


Bulk Flow Reaction Rates

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

where  Kb = a bulk reaction rate coefficient, C = chemical concentration (mass/volume), and n = a reaction order. Kb has units of concentration raised to the (1-n) power divided by time. It is positive for growth reactions and negative for decay reactions. Many bulk reactions can be modeled adequately as first-order reactions where n has value of 1.0. Estimates of Kb and n can be made by placing a sample of water in 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 (Ct/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.

EPANET can also consider reactions where a limiting concentration exists on the ultimate growth or loss of the substance. For growth reactions this can be expressed as

where Clim = the limiting concentration. A similar expression holds for decay reactions except that (Clim - C) is replaced by (C - Clim). This type of expression is particularly applicable to modeling the growth of disinfection by-products such as Trihalomethanes, where the ultimate formation of by-product is limited by the amount of reactable precursor present. Bottle tests can also be used to estimate Kb in this type of rate expression if the test is carried out long enough to measure Clim directly. (For 1-st order growth plot log [(Clim - Ct)/Co] versus time.)   EPANET will use this type of rate expression whenever a non-zero value is supplied for the limiting concentration.

Bulk reaction coefficients increase with increasing temperature. A rule of thumb is that reaction rates will double with every 10 deg. C rise in temperature. Running multiple bottle tests at different temperatures will provide more accurate assessment of how the rate coefficient varies with temperature.


Pipe Wall Reaction Rates

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

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 diameter). The latter term converts the mass reacting per unit of wall area to a per unit volume basis. EPANET limits the wall reaction order to either 0 or 1, so that the units of Kw are either mass/area/time or length/time, respectively.

The parameter Kw appearing in the above rate expression 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.

The wall rate coefficient can depend on temperature and can also be correlated to pipe age and material. See Wall Reaction - Pipe Roughness Correlation.

Note: 	EPANET requires that water be flowing in a pipe for a wall reaction to occur. Pipes with no flow have no computed wall reaction.


Importing a Partial Network

EPANET has the ability to import a geometric description of a pipe network in a format similar to that in which it exports a full network database to a text file. 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.

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]

<optional description of the file>

[JUNCTIONS]

<ID label of each junction>

[PIPES]

<ID label of each pipe and the ID labels of its end junctions>

[COORDINATES]

<Junction ID and its X and Y coordinates>

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.


FAQ-1
See Importing a Partial Network.


FAQ-2
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.


FAQ-3
Set the status of the pump to CLOSED. At the suction node 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.


FAQ-4
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.)


FAQ-5
Set the emitter coefficient at the junction of interest to a large value (e.g., 100000) and add the required pressure head (2.3 times the pressure in psi) to the junction's elevation. After running the analysis the actual demand at the junction equals the fire flow.


FAQ-6
Use a General Purpose Valve with a head loss 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.


FAQ-7
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.


FAQ-8
Add a Pressure Sustaining Valve to the end of the inlet pipe to the tank with pressure setting of 0. The elevation of the valve's nodes should equal the elevation at which the true pipe connects to the tank and should be higher than the maximum water elevation in the tank. Connect the discharge node of the valve to the tank with a short length of large diameter pipe.


FAQ-9
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 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.


FAQ-10
Bulk reaction coefficients can be estimated by performing a bottle test in the laboratory (see Bulk Flow Reaction Rates). 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 which produce simulation results that best match field observations).


FAQ-11
Add the booster station at a junction with zero or positive demand or at a tank. Use the Source Quality Editor to set the Source Type to CONCENTRATION and the Source Quality to the chlorine concentration that water leaving the node will be boosted to. Add the ID of a time pattern if you wish to vary the boosting level with time.


FAQ-12
THM growth can be modeled using first-order saturation kinetics. In the Reaction Analysis Options 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 be at least equal to the THM source concentration.


FAQ-13
Yes. This could prove useful in making side-by-side comparisons of two or more different design or operating scenarios.


Creating a Table

To create a table:

1.	Select View | Table or click the [image] button on the General Toolbar.

2.	Use the Table Options Dialog box that appears to select:

the type of table

the variables to display

any filters to apply to the data


Modifying a Table

To add/delete columns or to sort or filter the data in an existing table:

1.	Select View | Options or click the [image] button on the General Toolbar

2.	Use the Table Options dialog box to modify your table.

If a table has been filtered, a re-sizeable panel will appear at the bottom indicating how many items have satisfied the filter criteria.